GCA-TR-81-32-G
Prepared for
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Pesticides and Toxic Substances
Washington, D.C.
Submitted in Partial Fulfillment of
Contract No. 68-02-3168
Technical Service Area 3
Work Assignment Nos. 7 and 18
EPA Project Officer
James Bulman
ASBESTOS SUBSTITUTE
PERFORMANCE ANALYSIS
Revised Final Report
February 1982
Prepared by
Nancy Krusell
David Cogley
GCA CORPORATION
GCA/TECHNOLOGY DIVISION
Bedford, Massachusetts
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DISCLAIMER
This Revised Final Report was prepared for the Environmental Protection
Agency by GCA Corporation, GCA/Technology Division, Burlington Road, Bedford,
Massachusetts 01730, in partial fulfillment of Contract No. 68-02-3168,
Technical Service Area 3, Work Assignments No. 7 and 18. The opinions,
findings, and conclusions expressed are those of the authors and not
necessarily those of the Environmental Protection Agency. Mention of company
or product name is not to be considered as an endorsement by the Environmental
Protection Agency.
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CONTENTS
Figures v
Tables vi
Acknowledgments xi
1. Introduction 1
References 4
2. Paper Products 5
Introduction 5
Flooring Felt 7
Roofing Felt 12
Beater-Add Gaskets 18
Pipeline Wrap 23
Millboard and Rollboard 26
Specialty Papers 33
Commercial Papers 41
Electrical Insulation 46
Beverage and Pharmaceutical Filters 52
Cost Comparison 56
Current Trends 60
Conclusion 63
References 67
3. Friction Materials 75
Asbestos Product 75
Substitute Products 86
Cost Comparison 103
Current Trends 104
Conclusion 106
References 109
4. Asbestos Cement Pipe 114
Asbestos Product 114
Substitute Product 122
Cost Comparison 140
Current Trends 141
Conclusion 144
References 146
5. Asbestos-Cement Sheet 149
Asbestos Product 149
Substitute Products 152
Cost Comparison 164
Current Trends 165
Conclusion 167
References 169
iii
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CONTENTS (continued)
6. Flooring Products 172
Asbestos Product 172
Substitute Product 176
Cost Comparison 179
Current Trends 179
Conclusion 179
References 181
7. Gaskets and Packings 183
Asbestos Product 183
Substitute Product 187
Cost Comparison 210
Current Trends 212
Conclusion 214
References 216
8. Paints, Coatings, and Sealants 221
Asbestos Product 221
Substitute Products 226
Cost Comparison 240
Conclusion 243
References 245
9. Reinforced Plastics 248
Asbestos Product 248
Substitute Product 250
Cost Comparison 258
Current Trends 258
Conclusion 262
References 264
10. Textiles 266
Asbestos Product 266
Substitute Product 271
Cost Comparison 284
Current Trends 287
Conclusion 287
References 289
11. Miscellaneous Uses 292
Introduction 292
Drilling Muds (Fluids) 292
Cost Comparison 298
Current Trends 300
Conclusion 301
Shotgun Shell Base Wads 301
Asphalt/Asbestos Cement 301
Foundry Sands 303
Sprayed-On Insulation 304
Artificial Fireplace Ashes and Artificial Snows 305
References 306
12. Discussion, Results and Conclusion 309
Discussion 309
Results 311
Conclusion 317
iv
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FIGURES
Number Page
1 Section through a slim line pipe 135
2 The effect of temperature on the tensile strength of Kevlar®
29 Aramid 202
3 A circulatory system for a rotary drilling rig 293
v
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TABLES
Number
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
Estimated Current Annual Consumption of Asbestos Fiber in
Paper Products
Manufacturers of Asbestos Roofing Felt
Asbestos Roofing Company Production and Market Shares (1975)
Manufacturers of Asbestos Beater-Add Gasket Paper
Industrial, Commercial and Residential Use of Asbestos Mill-
board and Individual Applications
Manufacturers of Asbestos Specialty Paper
Manufacturers of Nonasbestos Specialty Papers
Manufacturers of Asbestos Beverage and Pharmaceutical Filters
Roofing Costs
Cost of Asbestos Millboard and Substitute Products ($ per
square foot)
Unique Properties of Asbestos Applicable to Friction
Materials
Typical Ingredients Used for Some Friction Materials (In
Weight %)
Property Modifiers in Friction Materials
Uses of Asbestos-Containing Friction Materials
U.S. Manufacturers of Asbestos-Bearing Friction Materials. .
Asbestos Consumption by the Friction Materials Industry
(Thousand Metric Tons)
Value of Asbestos Friction Material Shipments (In Millions of
1979 Dollars)
Page
6
14
14
20
28
37
41
53
57
58
76
78
79
81
83
85
85
VI
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TABLES (continued)
Number Page
18 Reinforcing Fibers and Other Materials for Friction
Materials 89
19 Brake Lining Treatment Formulation for Vermiculite-Based
Brakes 90
20 Cermet Friction Materials, Wt % 93
21 Passenger Car and Light Truck Usage of Nonasbestos Disc
Brake Pads 94
22 Police and Taxi Usage of Nonasbestos Disc Brake Pads on
Fronts 98
23 Nonasbestos Brake Manufacturers 103
24 Costs of Materials Proposed as Substitutes for Asbestos in
Friction Materials 104
25 Types of Water Main Pipe Now in Place (1975)-National
Projections of Mileage 117
26 Water Main Size Ranges by Type of Pipe Now in Place-Projected
Totals (1975) 118
27 Type of Sewer Main Pipe Now in Place-National Projections of
Mileage (1975) 119
28 Sewer Main Size Ranges by Type of Pipe Now in Place-Projected
Totals (1975) 120
29 Properties of Various Fibers for Use in Pipe Products .... 124
30 Vitrified Clay Sewer Pipe Production Figures 1973-1978. . . . 129
31 Typical Physical Properties of Major Thermoplastic Piping
Materials 131
32 Chemical Resistance Guide at Ambient Temperatures 132
33 Total Plastic Pipe and Fittings Production Volume Estimates
1960-1978 134
34 Estimated Production Volumes for Various Types of Pipe -
1974-1978 135
35 GRC Pipe Forms 137
36 Properties of Ductile Iron Pipe . . . 137
vii
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TABLES (continued)
Number page
37 Production Volumes for Cast Iron Pipe and Fittings 1973-1978 140
38 Pipe Price Estimates (Feb-1980) 142
39 Major Manufacturers of Asbestos-Cement Sheet Products .... 151
40 Performance of Possible Fiber Substitutes for Asbestos in
Cement Sheet 155
41 Comparison of Ebonized A/C with Hardboard 157
42 Cement Sheet Product Comparison 159
43 Substitute Product Manufacturers 163
44 Comparison of Cement Sheet Product Prices 166
45 Comparison of Siding Product Costs 166
46 Major U.S. Manufacturers of Asbestos Flooring 175
47 Manufacturers of Substitutes to Vinyl/Asbestos Floor Tile . . 179
48 U.S. Asbestos Gasket and Packing Manufacturers 188
49 Chracteristics of Fibers. 192
50 Fiber Usage Chart 193
51 PV Factors 197
52 pH Factor Determines Correct Factor Materials 198
53 Experimental Preference Rating Chart 199
54 Chemical Resistance of Yarn of Kevlar® 29 Aramid 203
55 Nonasbestos Raw Materials for Gaskets and Packings 205
56 Nominal Physical Properties of Nu-Board 1800 207
57 Typical Uses of Nu-Board 1800 207
58 Gylon® Physical Properties 208
59 Cost Comparison Between Asbestos Fibers and Substitutes
(1976 Dollars) 210
viii
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TABLES (continued)
Number Page
60 Costs of Asbestos and Substitute Gasketing 211
61 Cost of Various Packings 212
62 Unique Properties of Chrysotile Asbestos 222
63 Asbestos Uses in the Sealants Category 224
64 National Manufacturers of Asbestos Sealant Products 227
65 Substitutes for Asbestos in Resistant Linings and Coatings . . 235
66 Costs of Fibrous Materials for Roofing Coatings Compared
With Grade 7 Chrysotile 240
66a Pulpex Versus Asbestos Prices, $115 241
67 Costs of Substitutes in Resistant Linings and Coatings .... 241
68 Costs of Some Substitutes for Asbestos in Texture Paints . . . 242
69 Primary Manufacturers of Phenolic Molding Compounds 250
70 Cost Comparison 259
71 Forms of Asbestos Textiles Used in Asbestos Products 267
72 Asbestos Textile Grades 267
73 Asbestos and Substitute Fiber Property Comparison for Textile
Products , . . . 274
74 Characteristics of High Temperature Materials 276
75 Manufacturers of Nonasbestos Textile Fibers 278
75a Weavers and Fabricators of Textured and Other Fiber Glass
Yarn Products 279
75b Composition of E-Glass Fiber Substitute 281
76 Production Volumes of Nonasbestos Textile Materials 282
77 Substitute Product Property Comparison 283
78 Manufacture of Nonasbestos Textile Products 285
ix
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TABLES (continued)
Number Page
79 Cost Comparison Between Asbestos Fibers and Substitutes Used
in Textiles 286
80 Viscosifiers Used in Drilling Muds 297
81 Loss-Circulation Materials 299
82 Cost Comparison of Drilling and Mud Viscosifiers 300
83 Costs of Common Loss-Circulation Materials 300
84 Potential Substitute Products 318
85 Substitute Product Characteristics 321
x
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ACKNOWLEDGMENTS
Many GCA/Technology Division personnel contributed to the preparation of
this report. We wish to acknowledge the assistance of Ronald Bell,
Gene Bergson, Dave Cook, Timothy Curtin, Samuel Duletsky, Thomas Henderson,
Robert Mclnnes, E. Fred Mussler and Lester Pilcher. The following U.S. EPA
personnel reviewed the manuscript and provided technical guidance:
Richard Guimond, Robert Liss and James Bulman.
XI
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SECTION 1
INTRODUCTION
Asbestos is a generic term for a number of naturally occurring hydrated
silicate minerals that, when crushed or processed, separate into flexible
fibers made up of fibrils. There are six common asbestos forms: chrysotile
(or "white asbestos"), anthophylite, amosite, crocidolite (or "blue asbestos"),
tremolite/actinolite. Chrysotile asbestos is the form most commonly used,
since it is in ample supply. It accounts for about 95 percent of all the
asbestos commercially consumed. In addition to the different forms of asbes-
tos, there are varying grades, as well. Chrysotile asbestos is graded accord-
ing to the length of its raw fiber. The fibers are distinguished by separation
into eight groups numbered 1 through 8. Group 1 contains relatively long
fibers (up to 6 inches in length), while successive groups contain progres-
sively shorter fibers. The length of the fiber as well as the form of
the asbestos determine the specific properties of the asbestos and therefore
the uses to which the fibers are put. All forms of asbestos exhibit proper-
ties which make them useful in the production of industrial, commercial and
consumer goods. Specifically, asbestos fibers are strong, durable, resilient,
chemically and thermally stable, and resistant to heat, corrosion, rot, vermin
and chemicals. This diversity of properties has led to the widespread use of
asbestos in select mass-produced consumer items. Today, an average United
States resident could expect to find asbestos around his home in such products
as: floor tile, house siding, automobile brakes, appliance insulation, roof-
ing sealants, municipal water supply pipe, sewer mains and fireproofing for the
family wood stove. In all, approximately 1.6 kg (3.6 Ibs) of asbestos are
used in the country annually (1980) for every man, woman and child.*
Asbestos use is typically reported by major product categories. These
categories and their relative asbestos consumption rates are as follows:
Metric tons Percent of U.S.
Product category consumed, 1980 consumption
Asbestos paper 90,020 25.1
Friction products 43,700 12.2
Asbestos-cement pipe 144,000 40.2
Asbestos-cement sheet 7,900 2.2
Floor tile 36,080 10.1
Gaskets and packing 12,300 3.4
Paints, coatings and
Sealants 10,900 3.0
Plastics 1,500 0.4
Textiles 1,900 0.5
Miscellaneous 10,400 2.9
Total 358,700 100
*Assumes 1980 U.S. population of 210 million.
1
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These data were extracted from the Bureau of Mines asbestos consumption
figures for 1980.1 It should be noted that 1978 figures were 619,400 metric
tons total1 consumption, or a 42 percent decrease in asbestos consumed during
this 2-year period. Individual product categories differ slightly from those
reported by the Bureau of. Mines. For this report, the paper category includes
paper products, thermal and electrical insulation, and roofing felt. In addi-
tion, that portion of the flooring products asbestos consumption which is
attributable to flooring felt (approximately 60 percent),2 has also been de-
fined here as "paper products." These changes were made to consolidate the
presentation and group together all products which are manufactured by conven-
tional paper-making equipment.
Public health concerns over excessive exposure to asbestos fibers and
increasing regulation of the handling and use of raw asbestos have prompted
manufacturers to seek substitutes for asbestos containing products. These
substitutes take the form of fiber replacement in the original asbestos
product or a completely new asbestos-free alternative. This report details
the status of these substitutes.
A section of this report is dedicated to each major product category.
Each section considers both the asbestos product and the potential substitutes.
For both the substitute and the asbestos product, the following items are
addressed:
• Special qualities required,
• Product composition,
• Uses and applications, and
0 Product manufacturing summary, including a description of
the manufacturing process, plant locations, and production
volumes.
In addition, each section lists:
• Methodology, including search strategy and a summary of
contacts,
• Cost comparison (asbestos and nonasbestos) product,
9 Current trends,
0 Conclusion, and
e References.
Substitutes are grouped into both fiber and product descriptions for each
category. Sections which discuss multiple asbestos-containing products first
address each product, its manufacturing description, and its substitutes inde-
pendently. The cost comparison information, trends, and conclusions for all
products is kept apart and discussed at the end of the section.
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When available, the cost data are reported in 1980 dollars. These data
should be used for comparison purposes only, as actual costs are dependent upon
a variety of locally influenced factors. Every effort has been made to include
the major asbestos product substitutes that are commercially available. How-
ever, due to constant changes in this area, the list of substitutes for any
section may not be exhaustive. Nonetheless, this report covers, in detail,
the current status of asbestos product substitutes.
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REFERENCES
1. Clifton, R. A. U.S. Bureau of Mines, Mineral Industry Surveys. Asbestos
in 1978. August 22, 1979, and Clifton, R. A., Preprint from the 1980
Bureau of Mines Minerals Yearbook. Asbestos, p. 4.
2. The Resilient Floor Covering Institute. Comments on the Advanced Notice
of Proposed Rulemaking on the Commercial and Industrial Use of Asbestos
Fibers. Submitted to the U.S. EPA, Washington, D.C. February 18, 1980.
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SECTION 2
PAPER PRODUCTS
INTRODUCTION
Asbestos Paper Products are many and varied but may be defined in terms
of nine general categories, listed in order of descending annual (1980)
consumption rates:
• Flooring felt
• Roofing felt
• Beater-add gaskets
• Pipeline wrap
• Millboard and rollboard
• Specialty papers
• Commercial papers
• Electrical insulation
• Beverage and pharmaceutical filters
U.S. Bureau of Mines estimates indicate that, as a whole, asbestos paper
products consumed 90,020 metric tons of asbestos in 1980. This represents 25
percent of all asbestos consumed in the United States for this year.-'- Each
category within the general paper products scope is covered separately in this
section; commercial papers include general insulation, muffler paper, and
corrugated paper; specialty papers covers cooling tower fill, transmission
paper, chlorine electrolytic diaphragms and decorative laminates. The only
available estimate on relative asbestos use in the paper products category* is
presented in Table 1.
*Note: the breakdown of descending annual consumption rates given on this
page is derived from this table.
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TABLE 1. ESTIMATED CURRENTA ANNUAL CONSUMPTION
OF ASBESTOS FIBER IN PAPER PRODUCTS2
Category
Flooring felt
Roofing felt
Beater-add gaskets
Pipeline wrap
Millboard
Electrical insulation
Commercial paper
General insulation
Muffler paper
Corrugated paper
Specialty papers
Cooling tower
Transmission paper
Chlorine electrolytic diaphragms
Decorative laminates
Beverage and pharmaceutical filters
Total paper products
Metric tons
consumed
40,500
29,700
8,100
5,040
2,700
360
1,170
—
—
810
360
990
—
30
90,020*
Percent of
consumption
45
33
9
5.6
3.0
0.4
1.3
NA
NA
0.9
0.4
1.1
NA
0.03
100
NA = Not available but considered small.
*Total should be increased slightly to include subcategories without
figures.
Based on data from a 1979 report (Gordon & Riddle), a 1976 A. D. Little
report, industry contact in 1979, and 1980 Bureau of Mines figures.
Assumptions include the postulation that the percentage breakdown for
consumption remained approximately the same for 1980.
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This table has been revised from original 1979 format, to agree with the noted
downward trend in asbestos consumption. In 1979, for example, flooring felt
accounted for 118,000 metric tons of asbestos, roofing felt for 82,000 and
total consumption for the paper products category rested at 260,000 metric
tons. One year later, Bureau of Mines figures report total paper consumption*
at only 90,020 metric tons, with flooring felt decreased to 40,500 mt and
roofing to 29,700 mt. This table carries the same percentages of use into
1980, as data on varied percentages does not currently exist. However,
figures should be used accordingly.
Asbestos consumption appears to be declining for several reasons. One is
a noted downturn in the U.S. economy as a whole. This has led to a building
slump which further reduces the need for asbestos materials. In addition,
competition from the expanding substitutes market cannot be ignored.
Within this section each individual category is broken down into:
• Asbestos product
- Special qualities—product composition
- Uses and applications
Manufacturing summary—process, name and number of
manufacturers, and production volumes
• Substitute product
- Methodology—search strategy and summary of contacts
- Special qualities—product composition
- Uses and applications
- Manufacturing summary—process, name and number of
manufacturers and production volumes
In addition, an overall cost comparison, current trends, and conclusion are
presented at the end of the section.
FLOORING FELT
Asbestos Product
Special Qualities—
Asbestos is used in flooring felts to add dimensional stability and other
important properties necessary in flooring such as high moisture, rot, and
*Figures arrived at by product mix of BOM figures by GCA.
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heat resistance. These qualities have allowed asbestos to successfully
compete with previously successful flooring felt materials—organic and jute
felt—such that asbestos has now largely replaced them as a backing material.
It should be understood that this category covers the asbestos paper
product, felt, which, in the past was used extensively, by itself, as an
underlay for other flooring surfaces but now is used mostly in a combined form
as flooring carrier to vinyl-asbestos sheet flooring. This sheet flooring
product is covered under the Floor Tile section of this report as substitutes
to the floor tile and sheet products are similar.
Product Composition—
Asbestos flooring felts are composed of about 85 percent asbestos and 15
percent latex binder.-> The latex binder is normally a styrene-butadiene
type, although acrylic latexes have been used in the past.^ Chrysotile
asbestos is used with the shorter fibers, grades 5 through 7 predominating.
These grades are normally obtained from Canada although limited quantities are
available domestically. The domestic grades are mostly used, however, to make
vinyl-asbestos floor tiles in which the asbestos fibers are used as a
reinforcing agent for the vinyl and not as a backing (see Floor Tile section).
Uses and Applications—
Most asbestos flooring felt is sold commercially and is used in
residential applications. Due to its special qualities, asbestos felt backing
is used with vinyl sheet flooring as a general floor surfacing medium.
Asbestos backing is particularly useful in prolonging floor life when moisture
from below the surface is a problem.
A small quantity of flooring felt is produced for use without vinyl
coating.^ The rolls are made in smaller sizes than the rolls intended for
vinyl coating. This uncoated asbestos flooring felt is directly bonded (with
adhesives mopped on) to the floor deck at the job site and the final flooring,
which may be vinyl tiles, sheet vinyl, or carpeting is applied on top of the
felt. This particular use of asbestos felt is normally associated with
concrete bases where moisture exists. The asbestos paper helps to transfer
the water to the walls. The use of asbestos flooring felt without a vinyl
coating represents only a small fraction of its total use. However, it
appears that this use is becoming more popular."
Asbestos Product Manufacturing Summary—
Manufacturing process—Asbestos flooring felt is formed on conventional
papermaking machines with the end product in latex coated rolls. The felt is
then manufactured into a final consumer product by coating one side of the
felt with a resilient vinyl type surfacing, typically a plastisol or an
organisol. Plastisols are dispersions of homopolymers and vinyl acetate
copoymers of vinyl chloride in conventional polyvinyl chloride plasticizers;
an organisol is a plastisol containing a volatile diluent that lowers
viscosity.^ These vinyl surfaces are applied to the asbestos felt by
various extrusion coating, laminating, and spread coating methods.
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The basic operations steps in coating asbestos flooring felt with vinyl
include the following. The base asbestos felt roll is unwound and fed
continuously into the coating machinery. The vinyl surface is placed onto the
asbestos felt by the coaters; this process may also include various printing
techniques to enhance the appearance of the final flooring surface. The vinyl
plastisol, which is surface applied, can be colored by various additives or
techniques. Vinyl-coated felt is passed through a fusion oven because
plastisols cannot air dry; they require fusion temperatures of at least 121°C
for the copolymers, and 149°C for the homopolymers. Most of the heat from the
laminate is removed by chill rolls made of chrome-plated steel within which
high-velocity water is circulated. The sheet surface may be further decorated
by various chemical or printing methods before or after cooling. The vinyl
sheet structure is then edge-trimmed by razor, score, or shear cutting and
wound into a roll which is sold to customers, primarily in the construction
and floor-laying industry.
Name and number of manufacturers—Two major producers of asbestos
flooring felt are listed below:
Manufacturer* Location
Armstrong Cork Fulton, New York
Congoleum Industries Cedarhurst, Maryland
Armstrong Cork ships its product to their Lancaster, Pennsylvania,
factory for vinyl coating. The bulk of Congoleum's felt is sent to other
Congoleum plants for coating, although some is sold to a number of independent
flooring companies.
Brown Company of Berlin, New Hampshire, made asbestos flooring felt in
the past, but terminated their production a few years ago.^** GAF
Corporation formerly manufactured asbestos flooring felt in Erie,
Pennsylvania, but announced a commitment to end sales of asbestos paper
products effective April 1, I960.8 This has been confirmed by April 1981
phone contact."
Production volumes—Asbestos flooring felt is currently estimated to
consume about 40,500 metric tons, or approximately 45 percent of the asbestos
used in this product category each year placing it topmost among paper
products in annual fiber consumption.
*Nicolet Industries' plant at Norristown, PA, once manufactured asbestos
flooring felt but is now closed. New owners have bought out Nicolet and are
apparently working mainly on the production of nonasbestos products such as
sheet packing, millboard and monolithic products.'
**From this phone contact, it can be assumed that this means 1975-1976.
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Substitute Product
Methodology—
Search nlrM Logy---Informal Ion tibout a«bi:8to« flooring Celt was obtained
through both a literature search and phone contact with industry
representatives.
Summary of contacts—The following companies were contacted in the
process of researching this section of the report. Attempts were made to
reach other industry representatives, such as GAP, Erie, Pennsylvania, and
Fabri-Glass Incorporated, Moline, Illinois, but were unsuccessful.
• Mr. M. Schaum, Congoleum Incorporated, Cedarhurst, Maryland, August
1979
« Mr. H. Davies, Nicolet Industries, Norristown, Pennsylvania, July
1979
• Mr. E. Morse, Brown Company, Berlin, New Hampshire, July 1979
Special Qualities—
The advantage of asbestos-backed vinyl, as mentioned previously, lies in
its dimensional stability and moisture resistance. Dimensional stability
refers to the ability of the flooring to stretch and contract with temperature
changes and "settling" of the floor deck. The flooring should be able to
withstand these conditions without cracking, warping, or otherwise
deteriorating.
The recent development of backless vinyls is putting market pressure upon
asbestos-backed vinyl. "Backless" sheet vinyl is actually a sheet flooring
with a special vinyl backing; this special backing has excellent elastic
properties which allow the flooring to stretch and contract under the most
severe applications. Also, this backless vinyl is easier and faster to
install than asbestos-backed vinyl. It requires a minimum of adhesive deck
bonding, usually only around the edges, and can be stapled into place.
Foam-cushioned backings, formed by attaching a cellulose foam layer to
sheet vinyl surfacing, are also actively competing with asbestos backings.
Here again, the backing has very good dimensional stability and moisture
resitance. Also produced is a flooring system "sandwich" consisting of a
vinyl surface, a foam cushion midsection, and an elastic vinyl backing.
Backless vinyl and foam-cushioned backings appear to be good, commercially
available alternatives to asbestos-backed vinyl flooring.
Lextar reports that they have a very active program to replace asbestos
felt in roll vinyl flooring and have designed a performance effective felt for
this purpose. Information on the composition and potential cost of this
product may be found in subsequent sections.^
10
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The choice between carpeting and wood floors is usually made by customer
preference. Linoleum is rarely used at this time; there are no domestic
producers of linoleum, only importers. Residential customers also have the
option of buying the successful "place and press" vinyl tile squares instead
of a system which may include asbestos-backed vinyl.
An alternative such as organic floor backing has proven unacceptable
where moisture is present, and cannot be recommended for on or below grade use.
Product Composition—
Industry sources have begun research on other fibrous materials that
could replace asbestos; potential substitutes that have been studied include
fiberglass, cellulose, Nomex, and other polymeric fibers. At present, none of
these have been found to be an acceptable substitute for asbestos, and
therefore there do not appear to be any commercially available substitutes for
asbestos-backed flooring vinyl at this time. However, Lextar of Wilmington,
Delaware, reports active research towards production of flooring felt composed
of their Pulpex fiber, glass fiber, fillers, and binder resins.^^
Uses and Applications—
As previously discussed, asbestos substitute materials are used as
flooring coverings, replacing the need for asbestos felt backing in vinyl
floors, either by providing a complete covering in and of itself as in
carpeting, wood floors, and vinyl tile squares ("place and press") or by
providing another type of backing as in foam-cushioned backings and even
backless sheet vinyl. These floor coverings all display various properties
which must be considered and weighed by the customer before final product
selection.
Substitute Product Manufacturing Summary—
Name and number of manufacturers—Substitutes to flooring felt include
the various types of flooring systems commercially available. Fiber
substitutes are not a viable option at this time; however, companies such as
Lextar, a Hercules/Solvay Company, are performing extensive research in this
area. Such options as carpeting, backless vinyl flooring, foam
cushioned-backed vinyls, wood, vinyl-asbestos floor tiles, and linoleum all
act as readily available substitutes to asbestos flooring felt. The consumer
choice between these products and asbestos for flooring rests on personal
tastes, availability, ease and type of application, cost, etc. There are many
different manufacturers of these competitive products.
Production volumes—The production volumes of each of the substitute
products were not available at this time. For widely used floor coverings
such as carpeting and wood floors, the production volumes are expected to be
high. In contrast, production volumes of the newer replacement products are
only sufficient for testing purposes at this date.
11
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ROOFING FELT
Asbestos Product
Special Qualities —
Asbestos is used in roofing felts because of its dimensional stability
and resistance to rot, fire, and heat. Rot resistance is particularly
important due to roofing felt's use on flat or nearly flat roofs with poor
drainage. Given the rapid heating and cooling of roof surfaces some cracking
may occur, allowing for water penetration, particularly in damper climates or
in areas where snow, subject to periodic melting, has accumulated on the
rooftop. Asbestos felt resists cracking, perhaps better than any competing
product .
Asbestos roofing is considered by many roofers to have an exceedingly
long life. Some contractors contacted estimated that it would last
indefinitely. H»12 fo date, it has been in use for over 100 years with many
individual applications lasting up to 40
Product composition —
Asbestos roofing felts are composed principally of asbestos fibers (85 to
87 percent). 3 Other materials, such as wet and dry strength polymers, kraft
fibers, fiberglass, and mineral wool, are also often used as fillers. Sheets
are saturated with coal tar or asphalt. The paper is made in either single or
multilayered grades and may have fiberglass filaments or wire strands embedded
between paper layers for reinforcement. Usually grade 6 or 7 chrysotile fiber
imported from Canada is used in roofing felt.
Uses and Applications —
Two types of built-up roofs are used on flat surfaces. The most common
system, sometimes called a hot roof, involves the application of several plys
or layers of roofing felt alternating with asphalt or tar, often with a top
layer of gravel imbedded in the asphalt. The layers used may be organic,
fiberglass or asbestos felts. The second system is a cold roof not requiring
the application of hot tar or asphalt. Another, newer system of roofing,
which has been marketed in the United States for only 3 to 4 years, is a
single-ply membrane made of rubberized asphalt, PVC, or butyl rubber. Gravel
may be applied on the top surface as a ballast.
Asbestos roofing is primarily used for built-up roofing and as an under
layer for other roofing products. Roofing, the top cover of building
structures, includes the roof deck, insulation (if any), and the overall
weather protection surface. Asbestos roofing felts go back to the 1870s and
the orginal product line produced by H. W. Johns. ^ In 1968 the American
Society for Testing and Materials issued a recommendation for the use of
asbestos felt on built-up roofs^ which helped asbestos felts penetrate the
roofing market. However, the growth of asbestos roofing felts has tapered off
and is expected to continue to decline due to competition from substitute
materials. ^
12
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Built-up roofing is commonly prepared at the job site by cutting lengths
from product rolls to the required sizes and shapes. "Built-up" refers to the
practice of layering paper lengths on top of each other while hot roofing tar
is mopped between layers for adhesion and/or additional weather protection.
Built-up roofing is attached to the roof deck by adhesive tars or by nailing
if the roof deck can accept nails. There are three basic types of built-up
roofing: gravel surface, smooth-surface, and mineral surf ace. -^ Gravel
surface roofs and smooth-surface roofs are constructed similarly except in the
final surfacing; instead of the light mopping of asphalt used in
smooth-surface roofs, for gravel roofs a flood coat of hot asphalt is applied
and covered with aggregate gravel which serves more for appearance than for
actual protection. In mineral surface roofs, roofing paper is sealed with
weather grade asphalt embedded with opaque, noncombustible mineral granules
resulting in a roof in a choice of colors. In all built-up asbestos roofing,
saturated roofing felt is further coated with asphalt and tar during
installation, minimizing any potential fiber release during the roofing life
cycle.
As an under layer for other roofing products, asbestos roofing paper is
attached to the roof deck, again by tar adhesives or by nailing. It is then
covered by shingles, cement sheets or other forms of common roofing. Asbestos
paper, used as an underlayer, is generally applied in industrial and
commercial roofing rather than for residential
According to various industry sales persons, at least 60 percent of
asbestos roofing is applied during reroofing jobs while the remainder is
applied to new construction. In reroofing, removal of the old roof is
contingent upon several factors: the type and condition of the old roof and
customer perference. Aggregate roofs, such as gravel surface, must normally
be removed because they lack a smooth surface onto which the new roofing can
be attached. A badly damaged or warped roof must be removed for the same
reasons and because of the possibility that the roof deck itself has been
damaged and requires repair. On roofing jobs where the new roof may be built
over the old roof, the customer may want the old roof removed to reduce roof
weight. Conversely, the customer may not want the old roofing removed due to
added costs of disposal.
Asbestos Product Manufacturing Summary —
Manufacturing process — Roofing paper is a felted asbestos sheet
manufactured with varying formulations on conventional papermaking machines,
then converted into roofing felt by saturation with asphalt or coal tar. The
felt is pulled through a bath of hot asphalt or coal tar until It is
thoroughly saturated. After saturation, the paper passes over a series of hot
rollers to set the asphalt or coal tar into the paper. It may, on occasion,
be coated with extra surface layers of asphalt. The felt's thickness or grade
and the amount of asphalt coating required depend upon the product's intended
use. After saturation and coating, the paper passes over a series of cooling
rollers that reduce the paper temperature and provide a smooth surface
finish. Paper given extra coats of asphalt must be treated to prevent
adhesion between layers when the paper is rolled. The felt is then air-dried,
rolled and packaged for marketing.
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Name and number of manufacturers—There are two major domestic
manufacturers of asbestos roofing felt, as seen In Table 2. In the past, GAF
and Johns-Manville also manufactured roofing felt, but this product line has
been discontinued.9,17* plants listed make base felt which is later
saturated with asphalt. Saturation plants are not necessarily located at the
sites where the base felts are made; manufacturers of base felts may have a
number of saturation plants.
TABLE 2. MANUFACTURERS OF ASBESTOS
ROOFING FELT
Manufacturer
Celotex Corporation Lockland, OH
A subsidiary of Linden, NJ
Jim Walters Co.
Johns-Manville *
Corp.
Nicolet Industries Ambler, PA
Production volumes—Production of asbestos roofing felt in 1980 was
estimated at 29,700 metric tons, or 33 percent of the asbestos paper market.
Table 3 gives estimated company production and market shares for 1975.
Johns-Manville Corporation and GAF Corporation, which together produced
two-thirds of the asbestos roofing felt in 1975 will no longer produce
asbestos paper products after 1980**,16,18 (however, as stated previously,
J/M will continue to saturate asbestos felt).
TABLE 3. ASBESTOS ROOFING COMPANY PRODUCTION
AND MARKET SHARES (1975)3
Estimated Market
production share
Company (metric tons) (percent)
Johns-Manville Corporation
Celotex Corporation
Nicolet Industries
GAF Corporation
80,000
17,200
12,500
10,300
120,000
67
14
10
9
100
*Johns-Manville does not produce asbestos roofing felt in the U.S.; it is
produced in a Kinsey Falls, Montreal, J/M plant. However, J/M does saturate
asbestos felts (from Canada) with asphalt at the following U.S. locations:
Manville, NJ; Waukeegan, IL; Pittsburg, CA; Los Angeles, CA; Savannah, GA.16
14
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Substitute Products
Methodology—
Search strategy—The methodology utilized to research substitutes for
asbestos roofing felt consisted of both primary and secondary data
collection. In primary data collection, major manufacturers, distributors,
and roofing contractors dealing with organic, fiberglass, and single-ply
membrane roofing systems were contacted by phone- Manufacturers were a
primary source of technical data on roofing systems including the composition,
qualities, and performance of roofing felts, single-ply materials, historical
trends, market characteristics, and material costs. Roofing contractors
within the Boston area were contacted to determine regional costs,
construction practices, market demand, and perceived health problems
associated with various roofing felts. A building distributor was called to
cross-check regional trends of demand for these products and to identify
contractors using organic, asbestos, and fiberglass felts.
Summary of contacts—The following individuals were contacted by phone to
obtain information for this section.
• Mr. Charles McLaughlin, Estimator, Card M. Roofing, Somerville, MA
• Mr. Andy Noble, Assistant Sales Manager, Koppers Company, Eastern
Division, W. Orange, NJ
• Mr. Greg Perkins, R-625 Products Marketing Manager, Owens-Corning
Company, Toledo, OH
• Representative, Water Guidance Systems, Brainford, CT
• Representative, Carlisle Tire and Rubber Division of Carlisle
Corporation, Carlisle, MA
• Mr. Bob Mclntyre, Gates Engineering Company, Wilmingon, DE
• Salesman, Bradeo Supply Corporation, Woburn, MA
• Mr. S. Mullincamp, Research Director for Roofing Products,
Owens-Corning Company, Granville, OH
• Sales Manager, Asbestos Roofing Felts, Johns-Manville Corporation,
Manville, NJ
• Estimator, Gilbert and Becker Roofing, Dorchester, MA
• Estimator, McGrath Roofing Company, Dorchester, MA
• Dr. Philip Enterline, University of Pittsburgh, Pittsburgh, PA
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« Mr. A. Padavani, Johns-Manville Corporation, Denver, CO
• Mr. Jim Contorno, Bird & Son Co., Chicago, IL
• Mr. Henry Molvt, Koppers Company, West Orange, NJ
• Ms. Jayne Porter, Monier Company, Orange, CA
• Mr. Henry Chess, PPG Industries, Pittsburgh, PA
• Mrs. McKinney, Reichold Chemical Co., Irwindale, CA
Special Qualities—
Alternatives to asbestos roofing felt include organic felt, fiberglass
felt and a rubberized single-ply membrane roofing system. A well-installed,
built-up roof with an organic felt, good insulation and proper expansion
joints may last 20 years or more. As single-ply membrane systems are new to
the market their durability is not yet assured.
Organic felts, fiberglass felts and asbestos felts are all saturated with
coal tar or asphalt before use. Fiberglass felt is stronger, more durable,
longer wearing and more heat resistant than organic felt, but according to
some, because the material is so new, conversion will require both
manufacturing experience and applicator training.^
Single-ply membrane roofing is applied to the roof deck cold, an
important attribute when city ordinances or other considerations prohibit hot
tar. Some central business districts have ordinances to prevent installation
of built-up roofing due to the dangers associated with tar kettles. At 343°C
to 399°C the tar or asphalt mixture will burn and has, in some cases, exploded
causing damage to property and pedestrians. In these instances only the
newest of the systems (the single-ply membrane system) could be applied
because it does not require hot tar or asphalt.
Johns-Manville produces the Glas Ply built-up roofing system, a specially
constructed three-ply membrane with exceptional uniformity and natural venting
characteristics. The asphalt-impregnated fiberglass ply felts meet the 200
psi (at -18°C) tensile strength preliminary performance criteria recommended
by the National Bureau of Standards. It requires less mopping asphalt than
other systems because more asphalt is impregnated during manufacturing. The
material is compatible with asbestos base felts and Johns-Manville Asbestile®
flashing system. Uniform porosity allows deep penetration of asphalt leading
to improved interply adhesion.^0
Product Composition—
Organic felt is made primarily from cellulose fibers on papermaking
machines and, as with all roofing felts, is saturated with coal tar or asphalt.
Fiberglass roofing felt is made of glass or refractory silicate mixed
with binder. The exact composition is not available.^1 There are three
16
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basic manufacturing processes. Owens-Corning invented the continuous filament
process in 1964. The other processes involve shorter fibers; one uses a steam
blown process and the other employs a wet slurry process similar to the basic
papermaking process.
Single-ply membrane roofing is a laminate of a modified bitumen or rubber
and plastic or PVC. Typical is Koppers KMM System, a I60.-mil, five-layer
laminate composed of a thick plastic core protected on each surface by a layer
of modified bitumen and an outer film of polyethylene. Such a membrane is
loosely laid (i.e., without layers of tar) with a covering of loose gravel or
with a base surface where protection from the elements is afforded by other
means. The edges of the membrane are sealed together through the application
of heat, essentially ironing them together, or through the application of a
cold adhesive.
Uses and Applications—
Organic felts have been used in the United States in built-up roofing
systems for 25 years. Fiberglass roofing, although invented more than 15
years ago, has only recently has been accepted for widespread use. The
rubberized single-ply membrane roofing system has been used in the United
States for only 5 to 6 years but has been employed in Europe for 20 to 25
years.
Although in terms of strength and durability organic felt rates lowest
of the three felts, it is still the most widely used. Of the small sample of
roofing contractors contacted, it was estimated that 80 to 90 percent of their
built-up roofs utilized organic felts. Four or five other roofing companies
contacted used organic felts exclusively. The primary reasons for this
include the fact that organic felt is the lowest cost system and has been on
the market longest. Its qualities are well known.
Currently there are at least four companies manufacturing single-ply
membrane roofing systems.22-24 Q^Q of t^e chief advantages of this system,
as mentioned earlier, is that it can be applied to the roof deck cold and thus
avoids the need for hot tar or asphalt. Due to the dangers associated with
hot tar roofs in central business districts, some cities have considered
prohibiting the use of hot tar, encouraging the use of cold membrane systems.
Tile roof, becoming more common in the west and southwest, can be
installed when the roof surface is pitched but is unsuitable for flat,
built-up roofs. Where tiles are used there is no need for any type of
underlay.
Substitute Product Manufacturing Summary—
Name and number of manufacturers—At present, the fiberglass roofing felt
market is dominated by Owens-Corning. Other companies such as PPG Industries
and Reichold Chemical Company manufacture the basic fiberglass strand and sell
this to the paper manufacturers. Most of the producers of asbestos roofing
felt have diversified to manufacture competing nonasbestos products along with
their original output. Both Johns-Manville and Celotex produce organic
17
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felts, with Johns-Manville being one of the biggest manufacturers. Bird & Son
of Chicago, Illinois, Koppers Company in West Orange, New Jersey, and
CertainTeed Corporation also make organic roofing felts. The three major
companies produce both types of felt products, depending on market conditions
and consumer demand.*• 5
Single-ply membrane roofing is made by Carlisle Tire and Rubber Company,
a Division of Carlisle Corporation in Carlisle, Massachusetts; Water Guidance
Systems, a subsidiary of Plymouth Rubber Company in Brainford, Connecticut;
Koppers Company, Eastern Division, West Orange, New Jersey; and Gates
Engineering Company, Wilmington, Delaware.
Production volumes—Owens-Corning is the largest producer of the nation's
fiberglass roofing felt. When the conpany's organic felt sales are included,
it is responsible for a good portion of the total roofing felt market.^6*
Owens-Corning has presented a continuous filament Permaply product called
R-265 which was developed in 1964.21 Several other companies apparently
imitate this product with their own.
BEATER-ADD GASKETS
Asbestos Product
This subsection considers beater-add gaskets, so named because of the
process used in their manufacture—asbestos fibers and binders are added in
the beaters of the papermaking process. Other types of asbestos gaskets, such
as compressed sheet gaskets, are not paper products and are discussed
elsewhere, in the Packing and Gaskets segment of this report.
Special Qualities—
Asbestos is used in beater-add gaskets because of its unique combination
of qualities. It is not only heat resistant, resilient, and strong, but is
also chemically inert, which is important for many chemical applications.
Metal sheathed or jacketed gaskets take particular advantage of the resilience
of asbestos.** No other material currently available possesses all of these
characteristics for beater-add gasket applications. However, Rogers^'
reports that there are several commerically viable substitutes for asbestos
gasket papers available at the current time (see the Substitutes section),
both through their company and the other companies listed in the Substitute
Product Name and Number of Manufacturers section; other comments to the Draft
version of this report such as those from Victor Products Division of the Dana
Corporation substantiate this finding.
*Due to the competitive nature of this industry, phone contact with
Owens-Corning (11-17-81) indicated that the company prefers not to relate
production volume percentages. Therefore, adjectives are used to describe
production versus specific percentages.
**Inforraation from unpublished OSHA document on asbestos.
18
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Product Composition—
Beater-add gasket papers are composed of 60 to 80 percent asbestos fibers
and 20 to 40 percent binders, usually latex. The latex polymer used
determines the material's suitability for use in water, aqueous solutions,
oils, fuels, or chemical environments. Polymers used as binders in addition
to latex include natural rubber, various synthetic rubbers, neoprene, nitrile,
and other elastomers.
Nearly all domestic beater-add gaskets are formulated with various grades
of chrysotile asbestos although in the past, small amounts of crocidolite
asbestos were used on customer request since crocidolite is preferable to
chrysotile in applications involving strong mineral acids and alkalis. At
present, no domestic manufacturers report using crocidolite asbestos in gasket
paper.
Uses and Applications—
Gaskets are installed to obtain tight, nonleaking connections in piping
and other joints. Asbestos gaskets are used mainly by the automotive industry
in a variety of applications, including heat gaskets, carburetor gaskets,
manifold gaskets, and oil and transmission gaskets. In addition, asbestos
gaskets are widely used in other transportation applications, such as trains,
airplanes, and ships. Further, they are used in industrial and commercial
equipment of all varieties, including heat exchangers, boilers, furnaces, and
pipe connections. The chemical industry uses asbestos gaskets extensively for
piping, reactors, and equipment connections because of the high chemical
inertness of asbestos. Chrysotile gaskets are used when hostile environments
require glass reactors and piping; the gaskets are sometimes jacketed with a
polytetrafluoroethylene (teflon) sheath. A small number of crocidolite
gaskets have been made in the past, primarily for use in the chemical industry
because crocidolite, or blue asbestos, is even more inert to certain chemicals
than chrysotile. Blue asbestos gasket paper has also been used as a layering
material in sulfuric acid towers; chrysotile asbestos is no longer believed to
be used in this application.
Asbestos Product Manufacturing Summary—
Manufacturing process—Beater-add gaskets are manufactured on papermaking
machines as described previously and are considered paper products.
"Beater-add" gaskets are so named due to the fact that the binder is added
during the beater process in the production stages. Compressed sheet gaskets
are covered in the Gaskets and Packings section of this report.
Beater-add asbestos gasket paper is usually produced in a sheet or a
sheet roll that can vary in thickness from that of very thin paper to that of
millboard. The manufacturing process is similar to that of all asbestos paper
products. Gaskets fall into a product category (along with insulation paper,
flooring carrier, commercial and specialty papers, and electrical insulation
paper) requiring no further processing after the original paper forming
process other than cutting to size.
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While some manufacturing plants making beater-add gasket paper may
convert this intermediate product into a final product, most production is
sold to fabricators who make the final gasket. Gasket fabrication takes many
forms. Die-cutting is normally the first step. Here the gasket sheet is
machine cut to customer specified sizes and dimensions. However, die-cut
gaskets may be further processed by reinforcing the gasket with wire
insertions or by sheathing the paper with various metals, foils, plastics, or
cloth. Specific fabrication is, of course, dependent upon the final use.
Name and number of manufacturers—Domestic manufacturers of beater-add
gasket paper are listed in Table 4. Most gasket paper produced is sold to
fabricators who make the final consumer product. The 1978 edition of the
Thomas Register lists almost 200 fabricators of asbestos gaskets, but this
includes fabricators working with compressed sheet gaskets in addition to
those working with beater-add gaskets. :
TABLE 4. MANUFACTURERS OF ASBESTOS BEATER-ADD BASKET PAPER
Armstrong Cork Fulton, NY
Hollingsworth & Vose E. Walpole, MA
Boise Cascade Beaver Falls, NY
Colonial Fiber Company* Covington, TN
Nicolet Industries Norristown, PA
29
Johns-Manville Manville, NJ
30+
Rogers Corp. Rogers, CT
_
Manufacturers asbestos gasket paper, but not the
final product. °
tSome lines have been discontinued; plans are to con-
vert to nonasbestos in the near future (Telecon,
April 1981).
Production volumes—Annual asbestos fiber consumption in beater-add
gasketing was approximately 9 percent of the paper total, making it the third
largest use of asbestos in the paper products group. Only flooring felt and
roofing felt use more asbestos. Demand for asbestos gasket paper was expected
to increase in the future, but, due to the downsizing of automotive engines,
there may be a downturn in the use of asbestos gasket paper rather than
growth. The annual growth rate through the 1970s was developed through
technological change to asbestos paper gaskets from metallic gaskets. This
technological change is complete and cannot be counted on to bring about
further growth.13,31 Although a recent study^ expects an upward trend to
continue, industry sources anticipate slightly lower growth (assuming the
market to be free of competition from substitute products). The growth rate
for asbestos gasket paper in the late 1970's was one of the highest of all
asbestos products.
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Substitute Products
Methodology—
Search strategy—The search stategy used in compiling gasket information
included a literature review and telephone contacts with several leading
producers of substitute products.
Summary of contacts—The following companies were contacted by phone for
this subsection.
• Mr. Bill Brunner, Customer Service Manager, Chicago Gasket Co.,
Chicago, IL
• Mr. Barry Reznic, Applicatons Engineer, Cotromics Corp., Brooklyn, NY
• Sales personnel, Carborundum Corporation, Niagara Falls, NY
Special Qualities—
Alternatives to asbestos gaskets are made by the paper process with
asbestos being replaced by some type of mineral filler and/or fiber and/or a
high temperature-resistant organic fiber.27 Three basic alternatives to
asbestos beater-add gaskets exist: ceramic paper, teflon, and all-metal
products. Silicone rubber is also a potential substitute as it is serviceable
to 316°C; however, its applications are limited because it cannot be used in
the presence of certain oils and fluids. It should also be noted that many
facings may be made using the beater-add (Fourdrinier) process, with other
materials used in conjunction with this to produce a final gasket product
which, metal reinforced, etc., may be found in the Gaskets and Packings
section of this report. Specifically, this includes information on recent
developments in this field by Victor Products, a division of Dana Corporation.
Ceramic paper has the heat resistance of asbestos, but is not
particularly resilient and is deteriorated by oil,32 effectively eliminating
it from possible use in automobile gaskets. Ceramic paper does have good
resistance to some chemicals and in some high temperature applications has
even been shown to outlast asbestos paper as a layering paper in sulfuric acid
production. 33 Fiberfrax paper, composed of ceramic fibers, inert fillers,
and organic bonding agents can be used as a direct substitute for some
asbestos gaskets.-^
Teflon is not a resilient, rubbery material as is asbestos; rather it is
plastic, tending to deform and flow under loads. Due to its nonsticking
properties, teflon is difficult to retain in joints so it is commonly used
with an asbestos paper filler.
As with teflon, all-metal gaskets are not resilient, but are usable in
limited applications. Because of the lack of resilience, all-metal gaskets
cannot be substituted directly in most automotive applications.
Reports currently indicate that test results show asbestos-free materials
work very adequately in asbestos gasket applications and compare favorably
21
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with the asbestos-based product. Alternative materials that are commercially
reliable are being approved by OEM manufacturers and are equal in service life
to asbestos beater-add gaskets.31
Product Composition—
The substitutes for asbestos gaskets discussed include ceramics, teflon,
and metals. Teflon material is used especially by the chemical industry. The
Teflon Envelope Gasket manufactured by the Chicago .Gasket Company is composed
of fluorocarbon resins.35 For metal gaskets, a surface-to-surface seal is
accomplished by a ribbing in the metal surface which creates an airtight
connection when sealed. Ceramic papers, such as those produced by Cotromics
Corporation, are based on aluminum oxide,33 DUt exact formulas are an
industry secret. Fiberfrax paper is composed of ceramic fiber, inert fillers,
and organic bonding agents.
Rogers is reported to have offered the first nonasbestos gasket paper to
the market in January 1979. This grade was NOBESTOS D-7102, designed as a
nonasbestos substitute for Rogers GP/duroid 3102. In June 1979, a second
grade was introduced, NOBESTOS D-7280, designed as a substitute for Rogers
GP/duroid 3280. At present, Rogers has a total of ten grades of NOBESTOS
gasket materials, four of which (7101, 7201, 7301, 7701) are designed to
replace compressed asbestos (see also Gaskets and Packings section).^'
Hollingsworth and Vose reports similar developments in the nonasbestos
beater-add gasket field. This company has developed and supplied a wide
variety of nonasbestos beater-add papers to all of its gasket manufacturing
customers. In the Hollingsworth and Vose product, asbestos is replaced with
other materials which completely meet the physical requirements for gasket
papers. At this time, Hollingsworth and Vose (H & V) is commerically
producing a variety of gasket materials as asbestos substitutes, along with
exploration on applications of these products in other fields. The U.S.
Patent Office has recently granted a patent to H & V covering the technology
used to produce these alternative products.36
Substitute Product Manufacturing Summary—
Name and number of manufacturers—There are several manufacturers of
nonasbestos gaskets made from ceramic fiber papers, teflon, and metal. Three
prominent manufacturers of these products were contacted: Cotromics
Corporation of Brooklyn, NY; Carborundum Corporation of Niagara Falls, NY; and
Chicago Gasket Company of Chicago, IL. The Cotromics Corporation product is
called simply "ceramic paper," Carborundum's is called "Fiberfrax," and
Chicago Gasket's is called "Teflon Envelope Gasket." In addition, Rogers
Corporation provided comments to this report along with information on their
product. Other reported producers of nonasbestos beater-add gaskets are:
Garlock, Armstrong-Cork, Nicolet, Hollingsworth and Vose, and
Johns-Manville.27 Also, Victor Products Div. of the Dana Corp. in Lisle,
IL, makes asbestos-free gaskets. 37
Production volume—Production voluems are thought to be small, but
increasing. This will be subject to a greater increase as substitute products
gain market hold. Company representatives-^, 35 were not willing to reveal
present production volumes.
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PIPELINE WRAP
Proclucl
Special Qualities —
Asbestos paper has been successful as pipeline wrap due to the ability of
asbestos to resist soil chemicals, rotting, and decay, while maintaining
dimensional stability throughout its lifetime. These qualities are very
important for underground pipeline wrap, as well as for the few times that
asbestos pipe wrap may be applied above ground.
Product Composition —
Asbestos pipe wrapping papers contain a minimum of 85 percent asbestos,
are commonly reinforced with parallel strands of fiberglass for strength, and
are saturated with either coal tar or asphalt. They also may contain
cellulose and starch binders.
Uses and applications —
Asbestos pipe wrap protects underground pipelines from corrosion. The
wrapping paper is normally attached to the outside circumference of the pipe
by machine winding. On occasion, it is attached via hand winding during
special field fabrication of damage repairs. The wrap can be attached or
bonded to the pipe surface by special adhesive coatings or by hot enamels that
are coated onto one side of the paper. The coatings or enamels also aid in
the corrosion protection of the pipe.
The oil and gas industry is the largest user of asbestos pipe wrap for
their underground piping networks. The chemical industry also uses pipe wrap
in underground protection of hot water and steam piping (conventional
organic-Kraft-wraps rot away quickly in this function). Above-ground
applications are minimial — special piping in cooling towers is one such use.
Asbestos Product Manufacturing Summary —
Manufacturing process- — Asbestos pipe wrap is manufactured in similar
fashion to asbestos roofing paper. For pipe wrap, the felt is commonly
reinforced with parallel strands of fiberglass and saturated with either coal
tar or asphalt. The final product is normally a roll containing less tar and
coating than conventional asbestos roofing paper.
Pipe wrap is sold directly to pipeline construction companies such as
Williams and Mapco, and to pipe coating
Name and number of manufacturers — Manufacturers of asbestos pipe wrap and
their plant locations are listed below. Nicolet is reported to produce pipe
wrap in much larger quantities than is Celotex.-^
Manufacturer Location
Nicolet Industries Amber, PA
38
Celotex Lockland, OH
Johns-Manville^ Waukegan, IL
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Production volumes—Asbestos pipe wrap consumed 5.6 percent of asbestos
fiber used in paper products in 1979, placing it between millboard and gasket
use among the asbestos paper subcategories for that year. Exact production
volumes of individual manufacturers are not known.
Substitute Products
Methodology—
Search strategy—Industry contacts and an extensive literature search
were the two main approaches used to obtain information.
Summary of contacts—Below is a list of contacts made for this paper
category.
• Mr. Tony Silva, Johns-Manville Corporation, Denver, CO
• Mr. Bentle, New England Tape Company, Hudson, MA
• Mr. Bob Smith, Pyramid Plastics, Incorporated, Hope, AR
• Mr. Richard Dokmo, Tapecoat Company, Evanston, IL
• Mr. William Tinsley, Maror-Kelly Company, Houston, TX
• Mr. Terry Wright, D. E. Stearns Company, Houston, TX
• Mr. Chuck Lang, H. C. Price Company, Fairless Hills, PA
• Mr. Bill Power, PolyKen Pipeline Coating, Divison of Kendall
Company, Boston, MA
Special Qualities—
Saturated fiberglass is becoming more and more competitive with asbestos
in pipe protection because it has many of the characteristic advantages of
asbestos. A comparison of the pipeline protection of fiberglass and asbestos
is very similar to the discussion of fiberglass roofing felt versus asbestos
roofing felt. Fiberglass is more dimensionally stable, rot resistant, and
stronger than organic materials, yet asbestos still enjoys slight advantages
In these qualities. Asbestos also has a better fire rating than fiberglass.
Fiberglass has the advantage of requiring less asphalt saturation than
asbestos and, given the escalating cost of petroleum products, this may
eventually mean a lower cost.
In addition to fiber replacement In pipeline wrap, there are a variety of
asbestos-free coating materials which are potential substitutes. These
coating materials, which are discussed in Section 8, include:
• Enamels
• Extruded plastics—polyethylene and polypropylene
24
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• Fusion bonded thermosetting powder resins
• Liquid epoxy and phenolics
• Tapes
• Wax coatings
« Polyurethane foam insulations
• Concrete
Several of these materials have been on the market for years while others
have been introduced fairly recently. Although wax coatings, polyurethane
foam insulations and concrete may be used only in special situations, other
coatings such as extruded plastics provide excellent moisture, rot, and
chemical resistance as well as strength and therefore can be used in most
general applications.
®
Another potential substitute in this area is Fibercoat by Textured
Products, Inc., which lists pipe coverings as a potential application; in fact
this company reports that they have had major indications for Fibercoat use in
the duct and pipe installation industry.39 Information on this product may
be found under "Electrical Insulation."
Plastic tapes, although not adapted for use as pipeline wrap to date,
display excellent moisture resistance. However, some can be attacked by
various soil chemicals (depending upon application). Research in this area
may be applicable in the future if the use of plastic in pipe wraps looks
viable as an alternative; plastic has been used in this area in the past.
Product Composition—
Alternative systems include saturated fiberglass, plastic coatings, and
extruded epoxys and resins. More specific compositions are not available at
this time.
Uses and Applications—
Saturated fiberglass is used for the same applications as asbestos pipe
wrap. Plastic tapes have been used in pipeline protection for more than 20
years,^ although by themselves, they would probably not be a total
substitute for asbestos pipe papers because they can be attacked by various
soil chemicals in some instances and can crack or warp in others. Piping
layered with an extruded coating of epoxy resin has only recently become
commercially available. It must be time-proven during actual use if potential
users are to be convinced of its advertised properties.
Substitute Product Manufacturing Summary—
Name and number of manufacturers—Alternatives to asbestos pipe wrap
include saturated fiberglass, extruded epoxy resins, and, possibly in the
future, a type of plastic tape wrap. Plastic coatings are now available.
25
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Saturated fiberglass Is made by Johns-Manville corporation, which
headquarters at Denver, Colorado. Pyramid Plastics Incorporated in Arkansas
produces extruded epoxy resin coatings, and the New England Tape Company makes
plastic tapes, but to date, these are not applicable to pipeline use; instead
they are for coating smaller tubes and yarns. It is believed that plastic
tape coatings are available through other sources, such as PolyKen Pipeline
Coating Company, a Division of Kendall Company in Boston, MA.3
MILLBOARD AND ROLLBOARD
Asbestos Product
Special Qualities—
Due to the presence of asbestos fibers in millboard, it, like all
asbestos paper products, provides protection from fire, heat, and corrosion as
well as resistance to rot. In structure and texture, most millboard is
similar to a heavy cardboard. Asbestos millboard can be cut or drilled and
nailed or screwed to a supporting structure.
Millboard varieties differ in their ability to withstand elevated
temperatures—standard millboard is good to 427°C and high quality millboard
Is rated to 538°C. Above 566°C even high quality millboard becomes brittle.
The chrysotile fibers used to impart resilience, strength and heat resistance
suffer of major loss of strength in the region of 302°C to 496°C. It is rare
that a continuous working temperature in excess of 566°C can be withstood even
In unstressed situations.
Differences between grades are due largely to the different fibers used;
longer, higher quality fibers can resist higher temperatures. Also, high
quality millboard uses a calcium silicate binder as opposed to the starch
binder used in less expensive boards.^ However, premium grade millboards
capable of withstanding higher temperatures attain increased thermal
resistance at the expense of reduced strength.
As evidenced in numerous thermal Insulation applications, millboard has a
long service life. For example, once installed behind or beneath a wood stove
for heat and flame protection, millboard Is expected to last indefinitely.
Similarly, in industrial uses, such as linings for refractory brick in furnace
floors, long lasting thermal insulation is required, so millboard is
frequently used.
Rollboard differs from millboard in that it is thin enough to be rolled
to its thickness. It is usually sold in flat sheets." Both millboard and
rollboard contain a starch binder. Rollboard, being thin, is flexible, but
has a lower upper temperature limit of 177°C.
Insulating board, a high temperature resistant millboard manufactured
with amosite rather than chrysotile fibers has better board integrity and
lower shrinkage when exposed to fire. The boards are light weight, acid
resistant and easily machined.
26
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Product Composition—
Asbestos millboard is composed primarily of asbestos fibers; asbestos
content ranges from 68 to 95 percent by weight, with 70 percent considered
typical.4*»52 Group 5 chrysotile fibers are preferred. Binders, which may
be starches, elastomers, or silicates or, less frequently, glue, cement and
gypsum, usually account for 3 to 25 percent by weight. Mineral wool,
fiberglass, and cellulose are commonly used as filler.
Insulating board is a similar paper product consisting of asbestos with a
calcium silicate (lime/silica) binder. In this product, amosite is used
instead of chrysotile because it provides a higher degree of reinforcement at
low board densities and has favorable drainage properties-
Uses and Applications—
Asbestos millboard is rot-resistant, will stand up to many corrosive
gases and liquids, and is fire and temperature resistant. This makes
millboard particularly important as a lining in floors, partitions, ceilings,
and fire doors, and as an insulating barrier in stoves, ovens, and heated
appliances. It has important uses in metal and chemical industries as well.
Table 5 illustrates industry applications; each use is discussed in more
detail in the paragraphs that follow.
Asbestos Product Manufacturing Summary—
Manufacturing Process—Millboard is considered an asbestos paper product
because it is manufactured in essentially the same process as paper, using a
wet cylinder paper machine usually equipped with one or two cylinder screens,
conveying felts, pressure rolls and a cylinder mold. While paper produced on
a cylinder machine is made as a continuous sheet, millboard is not. A
cylinder rotating in a vat of slurry picks up a thin coating of fiber which is
removed from the cylinder and drawn through a press for partial dewatering.
The sheet is wound continuously onto a cylinder mold, a drum about 4 feet wide
and usually about 4 feet in circumference. The cylinder mold rotates,
collecting layers of fibers until the desired thickness is obtained. The
cylinder is then momentarily stopped as workers cut the built-up layer of
material lengthwise, removing one thick sheet of damp millboard. Once the
sheet is removed the cylinder starts rotating to build up another sheet. The
wet millboard, containing about 50 percent water, is air-dried or moved into
an autoclave or oven for rapid curing. Finished millboard usually contains 5
to 6 percent water.^l
Millboard is produced in a standard size in the United States, 42 x 48
inches, and ranges in thickness from 1/32-3/4-inch. The most popular
thicknesses are 1/4- and 1/2-inch. Thicker sheets are produced by laminating
sheets together. Rollboard is a lamination of two 1/6-inch or thinner sheets.
Name and number of manufacturers—Celotex, Johns-Manville (Waukeegan,
IL), and Quin-T Corp. (Tilton, NH) manufacture asbestos millboard.29>^3,44
GAF discontinued production of asbestos paper and rollboard as of April 1,
1980.8>18»^5 Nicolet has closed their Norristown, PA plant but may still
manufacture millboard elsewhere.7>43 Asbestos millboard products are
considered to be a mature or aging product group; sales growth is expected to
be slow to nonexistent.^
27
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TABLE 5. INDUSTRIAL, COMMERCIAL AND RESIDENTIAL USE OF ASBESTOS
MILLBOARD AND INDIVIDUAL APPLICATIONS2
Uaer
Individual application
Industrial
General
Electrical
Appliance
Aluminum
Marine, shipyard,
aircraft
Foundry
Steel
Metallurgical
Ceramic
Glass
Commercial
Metal-clad doors
Office partitions
In boilers, as gaskets, which may be metal rein-
forced, as flame and heat barriers, as slip-
planes for furnace linings, as rolls or discs to
convey a material from one point in the manufac-
turing process to another.
Thermal protection in large circuit breakers
Fire-proofing agent for commercial and home
security boxes, safes, and files
Pouring trough cover and trough liner
Liner for container that catches hot metal from
cutting operations
Trough liner and iron trough cover
Backup insulation for furnace lining
Used between the hot mandcel and the bearing
shell in molten babbitt operation
Low mass kiln cars
As insulation in glass tank crowns, melter,
refiner, sidewalls, etc.
Between outside metal and wood core
Between metal sheets, valued as a fireproofing
and sound deadening material. Very large
potential market
Soldering fixtures and
soldering blocks
Spark and glare shields
in welding shops
Fireproof wallboard
Washers in electrical
apparatus
Linings for safes, dry-
cleaning machines, incin-
erators, heater rooms
Garage paneling
Residential
Linings for home safes,
stoves, heaters and
electric switch boxes
Tent shields
Stove pipe rings
Stove mats, table pads*
Perfume rings for oil lamps
*Millboard is no longer used in toasters as element boards for wire insula-
tion. It has been replaced by reconstituted mica.
28
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Production volumes—The current level of asbestos millboard production is
estimated to be about 3 percent of paper products asbestos use. Research
Triangle Institute has estimated annual 1979 use for millboard to total 1500
tonB (1360 metric tons);4" 1980 figures used here indicate thut this figure
may be 2700 metric tons.-*-
Substitute Products
Methodology—
Search strategy—Data on asbestos and substitute millboard were gathered
through contacts with a number of companies that provided useful data on
product specifications, uses, prices, and market trends. In addition,
secondary sources provided information on general product trends and
substitute materials. An extensive literature search was also conducted.
Summary of contacts—The following individuals and companies were
contacted in the course of researching asbestos millboard.
« Mr. Carl Weber, Market Manager, Industrial Products Division,
Johns-Manville Sales Corp., Denver, CO
• Mr. Gary Morganson, Customer Services, Insulation Division,
Carborundum Corp., Niagara Falls, NY
• Ms. Carol Stein, Sales Representative, Pars Manufacturing Co.,
Ambler, PA
« Mr. Edmund Fenner, Director, Environmental Services, Johns-Manville
Corp., Denver, CO
o Mr. William F. Kiser, Marketing Manager, Ceraform Products,
Johns-Manville Corp., Manville, NJ
• Mr. Peter Heckman, Nicolet, Ambler, PA
• Mr. Neil Newell, Pyrotex, Carlisle, PA
Special Qualities—
The principal substitutes for asbestos millboard and rollboard are
fiberglass, mineral wool, and ceramic boards. When considering the
substitutes to asbestos millboard, it should be kept in mind that direct
comparisons are difficult, since the substitute specifications do not always
mesh exactly with the particular asbestos product specifications for a given
use in terms of temperature, resistance to corrosion, etc; they may instead
not match up to the asbestos product, or, in some cases, surpass the asbestos
product. For example, even though Carborundum's Fiberfrax boards can be seen
as an asbestos substitute, in actuality they can outperform asbestos at
temperatures above 538°C and thus fill a need that asbestos cannot. All of
the Fiberfrax millboards (trade-named "Duraboard," GH Boards," and "Hot
Board") have low thermal shock and chemical corrosion. GH Board and Duraboard
can withstand continuous temperatures of 1260°C without shrinking; Hot Board
is good to 1093°C.47
29
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Pars Manufacturing Company also makes a nonasbestos product called No. 9
millboard. This is good to 850°F, which is comparable to asbestos millboard.
Industry sources have indicated that this product is comparable in many other
respects to asbestos millboard, but more specific data are not available.^"
Johns-Manville Corp. produces a substitute to asbestos millboard named
Ceraforra 102 Board which has a continuous use limit of 1260°C. Other Ceraform
boards are Types 103, 126, 130, 141, and 143. In addition to the differences
in the binder used, the other products may be stronger than Type 102 or have
other specialized characteristics that make them suitable for specific
applications such as in molten metal containment.^' Ceraform board
applications overlap with the uses of the asbestos millboard but also fulfill
more diverse higher temperature uses for which asbestos millboard is not
suitable. Johns-Manville has designed a Ceraform type board that is suitable
for temperatures up to 816°C to 871°C. Ceraform 102 possesses low heat
storage, is corrosion resistant and has excellent thermal shock resistance,
much as the Carborundum Fiberfrax products.^
Babcock and Wilcox manufacture a ceramic substitute for asbestos in
millboard, Kaowool. For applications where thermal conditions are not severe
enough to warrant ceramic fibers, several types of mineral block and slab
products are available.50 Ceramic board uses overlap with those of asbestos
but may also be used in higher temperature range applications for which
asbestos is unsuitable.
Nicolet of Ambler, PA, is marketing two nonasbestos products, both under
the name of Millboard. Details on their qualities are not known, 51
Pyrotex of Carlisle, PA, is also manufacturing asbestos-free millboard,
but details on this product were not available.->2
Ceramic fiberboards mentioned here cannot substitute for asbestos
millboard in most gasket applications. They are not resilient enough and also
are deteriorated by oils.
Alumina-silicate boards, made by Pars Manufacturing Company and
Carborundum, are available in thicknesses of up to 50 mm. If purchased with a
special high temperature silica binder, these boards may be used successfully
in applications such as process rollers for plate glass manufacture as a
direct substitute for asbestos millboard.
Vermiculite may be a substitute in insulation boards, as it has both
insulation and protection properties. Usually it is combined with glass fiber
to achiever greater structural integrity.
Another possible replacement for areas such as duct insulation is
Fibercoat® by Textured Products, described in "Electrical Insulation."
30
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Janos Industrial Insulation Corporation calls its asbestos millboard
replacement NuBoard. It will not burn and is resistant to temperatures up to
982°C, depending upon application.^3
Victor Products Division of Dana Corporation markets a Mineral Board,
which, when used with overlaps, flanges, and grommets to enclose the board, is
resistant to fluids as well as heat and pressure. Typical applications
include cylinder heads, manifolds, and other areas where pressure resistance
Is required.54
Product Composition—
The substitute product "Fiberfrax," by Carborundum, is composed of
alumina-silicate (ceramic) fiber and inorganic binders. The Pars
Manufacturing Company's nonasbestos "No. 9 millboard," is made of an
alumina-slicate high temperature refractory material.^° More specific data
on these products are not available.
Johns-Manville's Ceraform 102 Board is similar to the other substitutes,
composed primarily of a refractor fiber consisting of silica and alumina with
a small amount of organic material. Ceraform boards are vacuum formed from a
slurry of raw materials and dried to a predetermined hardness. Organic
materials present in the Type 102 board burn out at 260°C, but a more
expensive board containing only inorganic binders and suitable for
temperatures up to 816°C to 871°C is available for applications where this may
present a problem.
The mineral board produced by Victor Products contains mostly inorganic
materials with minimal organics present. It is white in color.^^
Vermiculite encompasses a group of hydrated alumina silicates resembling
mica in appearance. Bulk material costs are low, but costs rise after
vermiculite undergoes exfoliation, an expansion that occurs upon heating.
Exfoliated granules may be delaminated to form vermiculite plates for
insulation boards or alkali-resistant glass fibers may be added in a
lime-silica matrix to combine the insulation and fire protection properties of
vermiculite with the structural integrity of glass fibers. Perlite, similar
to vermiculite, may also be used as a substitute for this application. It is
a naturally occuring noncrystalline silicate of volcanic origin.
Information on the composition of both the Pyrotex and the Nicolet
products was not available to the writers at the time of issue of this report.
Uses and Applications—
Carborundum's Fiberfrax is used in a variety of ways to substitute for
asbestos paper products including millboard, rollboard, commercial paper,
textiles, and insulation fibers (covered in other sections). Various boards
differ in density, thicknesses, hardness, and strength; uses of these products
31
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vary according to the need for strength and hardness-55,56 Fiberfrax board
is currently being used in place of asbestos millboard in the following
applications:
• Thermal protection in large circuit breakers
• Fireproofing agent for commercial and home security boxes, safes,
and files
• Molten aluminum pouring trough covers and liners
• Liners for catching hot metals being cut in shipyards
• Trough covers and liners in the steel and foundry industries
• Backup insulation for furnace linings
• Heat shields for personnel protection
• Rigid, high-temperature gaskets
• High-temperature baffles and muffles
e Chimney and furnace linings
« Hot gas duct linings
• Expansion joint material
Pars Manufacturing Company's No. 9 millboard has uses similar to asbestos
millboard. The Johns-Manvilie product, Ceraform 102 Board, is similar to
Fiberfrax. Typical applications include furnace and kiln linings and as
backup insulation. •*
Special applications for the Pyrotex and Nicolet products are unknown at
this time.
Substitute Product Manufacturing Summary—
Name and number of manufacturers—Several companies have developed
substitutes for asbestos millboard and similar asbestos paper products.
Examples are ceramic fiberboards by Carborundum Company and ceramic board with
Kaowool by Babcock and Wilcox. Johns-Manville^^ ^ and Pars
Manufacturing^® also have nonasbestos millboards. The Johns-Manville
product is trade named "Ceraform 102 Board." Nicolet has also developed
nonasbestos millboard substitutes as well as the Pyrotex Company of Carlisle,
Pennsylvania. In addiiton, Janos Industrial Insulation Corp. of Moonachie,
NJ, makes NuBoard as an asbestos millboard replacement, and Victor Products
Division of Data Corporation makes a mineral board replacement.
32
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Production volume—Nonasbestos substitutes for asbestos millboard are
being used in place of asbestos millboard in some applications- As tbere are
many individual uses, each with individual requirements, the current
production volume of substitute products could not be quantified at this time,
although it is expected to grow.
SPECIALTY PAPERS
Asbestos Product
Special Qualities—
There are six major classes of asbestos specialty papers:
• Cooling tower fill
« Transmission paper
« Beverage and pharmaceutical filters*
• Electrolytic diaphragms
• Decorative and industrial laminates
e Metal linings
These classes were chosen after extensive discussions with industry
representatives; although other types of specialty papers may be produced, the
quantity of asbestos used in their manufacture is minimal.
Asbestos is used in specialty papers primarily due to its chemical and
heat resistant properties.
Asbestos is used in cooling tower fill for its heat and chemical
resistance. In applications where high heat resistance is necessary, asbestos
paper will continue to be used, because of its proven durability and heat
resistant qualities. Extensive government testing at governmental facilities
at Oak Ridge-^ found asbestos fill (Asbedek) superior in performance to
alternatives.
Asbestos is used in transmission papers for its excellent friction
characteristics and oil resistance as, during use, the paper-lined disks are
normally coated with transmission oil. Asbestos has been found to be durable
in this application.
*Covered separately in last Paper Products section.
33
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For beverage and pharmaceutical filters, asbestos represents a mineral
medium that does not degrade or otherwise affect liquid quality while acting
as a suitable filter. In the electrolytic diaphragm, it provides strength and
the appropriate properties needed for manufacturing this product. In the
electrolytic process, cathode surfaces are generally lined with a layer of
asbestos either in the form of paper or as vacuum-deposited fibers.^9 The
asbestos maintains the caustic strength and minimizes the diffusional
migration of hydroxyl ions. All diaphragms gradually clog with residual
impurities in the brine and particles of graphite from the anode, and
therefore must be renewed at regular intervals (approximately every 100
days).60
High-pressure industrial laminates are a significantly more durable form
of the decorative product. Asbestos is no longer being used in any
significant quantity in making decorative laminates.6^ Asbestos paper was
used to produce a speical fire-retardant decorative laminate; fire retardant
laminates are used for interior surfacing and paneling in public buidings,
buses, railcars, and ships requiring a Class 1 fire-resitant rating."^
Decorative laminates are thin, rigid sheet materials that have been resin
saturated to press the layers together. They are faced with decorative colors
or patterns and characterized by showing resistance to damage from scuffing or
scratching.61 Industrial laminates are sheets produced from asbestos
electrical paper fused at high temperatures. Asbestos electrical paper is
used here to allow for effective insulation and to protect the conductor from
fire.
Asbestos is used in metal lining paper to provide corrosion-resistance
and strength.
Product Composition—
The base for cooling tower fill consists of a blend of two grades of
chrysotile asbestos bound with DuPont neoprene latex; the content is 90 to 91
percent asbestos and 9 to 10 percent binder.6^ Baltimore Air Coil asbestos
fill (MNA) is composed of a base asbestos paper saturated with melamine, a
thermosetting resin."
Asbestos transmission paper is a latex-bound product currently made with
chrysotile asbestos. Although it has been reported in a survey of consumers
that this paper was made with crocidolite (blue) asbestos,6^ it is currently
believed to be made solely with chrysotile asbestos due to supply and health
problems associated with crocidolite.6->
Electrolytic diaphragms are made from mixing asbestos fibers and water to
form a slurry. Decorative laminates are produced by impregnating asbestos
electrical paper with thermosetting resins and then fusing multiple layers
together at high temperature and pressure. They are made up of asbestos paper
which contains asbestos and a phenolic or melamine resin and is formed in
thin, rigid sheets and then colored or patterned accordingly. Industrial
laminates consist basically of asbestos fibers, combined to make electrical
paper with thermosetting resins added.
34
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Metal lining paper is manufactured like commercial asbestos paper except
that the metal lining paper contains a higher percentage of binder and a small
percentage of clay.
Uses and Applications—
The major use of asbestos fill in cooling towers is in applications where
high heat resistance is necessary. One such application is in gaseous
diffusion as performed at the governmental facilities in Oak Ridge. The
Hunters Corporation produces a fill, "Asbesdek," used mainly in mechanical
draft towers.
Automobiles equipped with automatic transmission get their drive from
metal transmission disks covered with a super-tough asbestos paper.^4 Four,
six, and eight cylinder autos with power shift contain from 8 to 12 of these
paper-lined disks.
Asbestos beverage filter paper is used by beer, wine and liquor
distilling industries to remove microorganisms and fine solids from the liquid
medium. Pharmaceutical and cosmetic industries use the paper as well.
Asbestos is used as a diaphragm in production of chlorine via brine
electrolysis. Asbestos paper sheets were used in diaphragm cells through the
1930s and 1940s but now almost all diaphragm cells made with asbestos use a
slurry"^ of water mixed with asbestos, rather than as a paper. The slurry
is vacuum—deposited onto a cathode pole, and the diaphragm is built—up inside
the electrolysis cell.
Decorative laminates can be bonded to plywood, fiberboard, or metals and
can be sawed, drilled or sanded with conventional woodworking equipment.
Decorative laminates appear generally in wall or ceiling paneling, desk tops,
counter tops, and worktable tops- Asbestos is only one of many materials from
which decorative laminates can be made; the bulk of decorative laminates are
made with kraft papers. Industrial laminates are used for telephone
switchboard construction, television circuit boards, and other electronic
applications. Tube and rod laminate can also be used as core or winding
barriers for such equipment. The sheets can also be stamped or fabricated
into specialty spacers or washers.
Metal lining paper is used as a corrosion-resistant liner for both metal
sidings and culvert pipe. Culvert pipe is in turn used for landfill drainage
and water treatment applications.
Asbestos Product Manufacturing Summary—
Manufacturing process—A wet cooling tower dissipates heat from water by
maximizing the water-air interface, either with splash-type fill or with
film-type fill. Splash-type fill which can consist of asbestos paper,
polyvinyl or polypropylene plastics, cellulose, asbestos-cement sheets,
aluminum or steel creates small liquid droplets which drip down onto another
surface, splash, and reform."^ Film-type fill, made of similar materials,
spreads the water over large areas in a thin film, exposing it to the air.
35
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The Munters process for fill production impregnates fluted sheets of
asbestos paper with about 20 percent of a saturant formulated on a chlorinated
rubber base. The fluted sheets are bonded together with neoprene latex to
form packs with 3/4—inch deep neoprene reinforced edges. The maximum size of
individual packs is 12 x 12 x 72 inches.63 The cooling tower fill made by
Munters is trade named "Asbesdek" and looks like a stack of corrugated sheets.
Baltimore Air Coil manufactures asbestos fill (MNA) for use mainly in
air-conditioned buildings, machinery, and computers. The base asbestos paper
is saturated with the thermosetting resin Melamine.63
• In transmission paper, the base paper is saturated with phenolic resins
to create a very hard and resilient product in a saturation process similar to
that described for cooling tower fill. The saturated and hardened paper
product is then cut to the required size.
Beverage and pharmaceutical paper is made on conventional papermaking
euqipment; metal lining paper is manufactured similarly to commercial paper
discussed previously.
Currently, almost all commerical asbestos diaphragm cells use a slurry
instead of the paper sheets mentioned previously. The slurry is made by
mixing fibers with water, then vacuum depositing the slurry through a
perforated plate onto the cathode pole. Happ (Hasker asbestos Plus Polymer)
diaphragms are basically the same but add a fluoropolymer resin to the slurry
to help diaphragm bonding while reducing voltage load. The use of paper
sheets has diminished because the voltage load is significantly higher with
paper as opposed to vacuum deposited slurry.
Decorative laminate sheet is formed by saturating successive layers of
paper with either a phenolic or melamine resin. The layers are then pressed
and cured. Industrial laminates are made by impregnating asbestos electrical
paper with thermosetting resins and then fusing multiple layers together at
high temperature and pressure.
Name and number of manufacturers—There are reported to be approximately
11 domestic manufacturers of asbestos specialty papers. Munters Corporation
of Fort Myers, FL, and Baltimore Air Coil of Baltimore, MD, are secondary
manufacturers of cooling tower fill but the base asbestos paper stock is
manufactured by Nicolet in Ambler, PA, and GAF Corporation in Erie, PA. A
large amount of asbestos transmission paper is sold to the Delco-Moran
Division of General Motors for fabrication. Johns-Manville was to have
discontinued manufacturing of specialty asbestos paper in April 1980."7,68
Westinghouse's Decorative Micarty Division markets decorative laminates, but
reports that asbestos is no longer used in any significant quantity."-*- The
manufacturers of individual asbestos specialty products may be found in Table
6. In addition to the manufacturers listed, Johns-Manville makes specialty
papers in Manville, NJ, and Waukegan, IL; and Lydall (Colonial Fiber) produces
them in Covington, TN, and Rochester, NH. J/M and Nicolet produce asbestos
paper which is sent to secondary processors for further fabrication.
36
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TABLE 6. MANUFACTURERS OF ASBESTOS SPECIALTY PAPER
Type of specialty paper
Manufacturer
Cooling tower fill
Transmission paper
Electrolytic diaphragms
Decorative laminates
Industrial laminates
Metal lining paper
Munters Corp., FL*69
Baltimore Air Coil, MD*
NA
NA
Westinghouse - Decorative Micarty Div.**
NA
Jim Walter - Armco Steel Co. of Ohio
(Celotex),
Linden, NJ and Lockland. OH
GAF, H. H. Robertson Co.^
Erie, PA
NA = Not available.
*
Secondary processors.
**
No longer produced in any significant quantity—in fact, reports
indicate that asbestos is no longer used in this product at this
location.70
The first company listed manufactures the base felt and sells this
product to the second company which uses it to line pipes.
37
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Production volumes—The major use of asbestos fill has been in general
cooling tower applications; however, the asbestos fill is becoming too
expensive compared to readily available plastic fills and the volume of
asbestos paper used for cooling tower fill is decreasing.58 It has been
estimated that several thousand tons of asbestos fiber were formerly consumed
annually to make cooling tower fill.3 Currently about 810 metric tons are
used in cooling tower applications.
Other specialty paper products use much less asbestos. In 1980, an
estimated 360 metric tons of asbestos fiber were consumed in the production of
automatic transmission paper (updated from 1977 estimate referenced).65
This figure was probably only 360 metric tons in 1980 (see Table 1). As
indicated, decorative laminates made with asbestos are no longer produced in
any significant volume. The specialty grade of asbestos paper manufactured
for use as a diaphragm in electrolytic cells uses minor quantities of
asbestos. '*• While no production volumes for this specialty item are
available, it is estimated that less than 990 metric tons of asbestos are used
annually (1981 data) About 0.54 kg of asbestos is consumed during
electrolytic cell operations to produce 0.9 metric tons of chlorine.59
Annual production of chlorine is on the order of 9 million metric tons'^ and
about 70 percent of the American chlorine is produced by the diaphragm cell
process, •* indicating that approximately 38 thousand metric tons of asbestos
were estimated to be consumed annually in electrolytic cells (1977). Almost
all of this asbestos is in the form of slurry, not paper.
In sum, with estimated tower fill consumption of about 810 metric
tons/yr, transmission paper use of 360 metric tons, electrolytic diaphragms
requiring approximately 990 metric tons, decorative laminates and other
miscellaneous categories with no available figures, but considered small by
industry sources, the most recent estimate of total consumption of specialty
papers would be about 2106 metric tons annually.-*-
Substitute Product
Methodology—
Search strategy—A combination of a literature review and a telephone
survey of industry representatives was used to gather data on asbestos
specialty papers and their potential substitutes.
Summary of contacts —
• Mr. J. Skold, Hunters Corp., Fort Myers, FL, August 1979
0 Mr. M. Lai, Hooker Chemical Co., Niagara Falls, NY, August 1979
« Mr. B. Pedersen, Sales, E.I. DuPont de Nemours, Co., Wilmington, DE,
March 1980
9 Mr. D. Cannady, Decorative Mircarty Division Manager, Westinghouse,
Corporation, Hampton, SC, August 1979
38
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• Mr. J. F. Reis, Johns-Manville Corporation, Denver, CO
• Mr. E. M. Fenner, Johns-Manville Corporation, Denver, CO, July 1979
• H. H. Roberston Co., sales personnel
Special Qualities of Product—
Substitutes for specialty papers include:
Specialty paper Substitute product
cooling tower fill polyvinyl and polypropylene plastics
cellulose
aluminum
steel
transmission paper none, but research and development
currently underway in this area
beverage and pharmaceutical cellulose and glass fibers (see next
filters section for detail)
electrolytic diaphragms Nafion membrane cell
PTFE
laminates chemically treated papers
glass and ceramic papers
kraft papers
metal linings paper Veriscore
Asbestos-cement sheet use as cooling tower fill is rapidly decreasing due
to its potential for wear and fiber release under extreme conditions. A wide
variety of substitute materials are currently available for cooling tower fill
including polyvinyl and polypropylene plastics, cellulose, aluminum, and
steel.58,63 Metal substitutes are more durable; fire resistant metal
laminates are.economical and are now on the marketplace. Fill substitutes
must be chemical resistant as well as flame resistant.
Tests have shown it to be difficult to find a material capable of
substituting for asbestos in diaphragms for brine electrolysis which can
perform as well. At present, an asbestos diaphragm has a useful life of 6 or
7 years.^ Electrolytic diaphragm substitutes have been tested by Hooker
Chemical in Tacoma, Washington, and by Diamond Shamrock Chemical in Muscle
Shoals, Alabama, ^-> and show the new membrane cell to have a number of
advantages over the asbestos diaphragm. It produces a stronger caustic
solution, reducing evaporation required to make a concentrate, lowers the salt
content of the caustic and the chlorine produced contains no hydrogen
impurities. However, the membrane cell developed by DuPont is not as
efficient electrically as asbestos diaphragms. This ion exchange method has
39
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shown less energy efficiency than the percolating diaphragm method used in the
past. For example, Hooker's electrolytic cell with membrane consumes 3110
kWh/metric ton of chlorine produced compared with 2780 kWh/metric ton for
asbestos.°6 Membrane materials are not interchangeable with asbestos
diaphragms. Such modification would be feasible only when a new plant is
being built or an entire plant is being reworked. Similarly, mercury cells
which eliminate asbestos diaphragms entirely are available, but are not
interchangeable with existing electrolytic diaphragm cells.?6 About 0.5
percent of chlorine is thought to be produced by ion exchange and 19.5 percent
by a mercury-amalgam method.
Product Composition—
For most applications any of the materials mentioned for cooling tower
fill substitutes are adequate. An alternative to asbestos electrolytic
diaphragms is DuPont's Nafion membrane mentioned previously. It consists of a
film of perfluorosulfonic acid resin (copolymer of tetrafluoroethylene) and
another monomer to which negative sulfonic acid groups are attached.
Promising results have also been obtained with a 2-layer diaphragm
polypropylene (PTFE). This cell has a resistance inside the electrolysis cell
which is comparable to that of asbestos. Tests carried out over a period of
1100 hours did not show significant deterioration.
As for metal linings, H. H. Robertson Co. has produced "Veriscore," which
is manufactured in the same manner as their Galbestos sheet-siding which
contains asbestos phper, except that the asbestos paper lining is replaced
with a 3 mil thick layer of epoxy resin. Various types of specially painted
sheets can also be used as a siding substitute for Galbestos.
Economical, fire-resistant laminates that use chemically treated papers
as a laminated substrate and/or laminating resins containing flame-retardant
chemicals are available. Also, glass and ceramic paper substrates are used
when the extra cost is acceptable. For decorative laminates, asbestos papers
have been replaced by Kraft papers.
The fiber size distribution of specialty paper substitutes varies from
product to product. Most substitutes mentioned, such as the Nafion membrane,
aluminum tower fill and glass paper substrates do not contain fibers.
Specific fiber sizes for substitutes containing fibers were not available.
Uses and Applications—
Nonasbestos cooling tower fill is a direct substitute of the asbestos
product. New diaphragm products substitute for asbestos products, and supply
some advantages such as a stronger caustic solution for producing concentrate
to offset the disadvantage of higher energy costs. Metal lining substitute
products enjoy uses similar to their asbestos counterparts, as do decorative
laminates. No substitutes for asbestos transmission paper appear to be
available.
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Substitute Product Manufacturing Summary—
Name and number of manufacturers—Two manufacturers of nonasbestos
substitutes are listed in Table 7. An alternative to asbestos diaphragms in
eletrolytic cells is a membrane cell formed from DuPont's Nafion
membrane^O'^ which has been developed and demonstrated by Hooker Chemical
Company•
TABLE 7. MANUFACTURERS OF NONASBESTOS SPECIALTY PAPERS
Asbestos product Substitute Manufacturer
diaphragm membrane cell- DuPont de Nemours & Co./
Nafion Hooker Chemical Co.
metal lining Versicore H. H. Robertson Co.
paper
The H. H. Robertson Company has developed and markets "Veriscore" as a
substitute for their asbestos-containing Galbestos sheet siding.
Data on manufacturers of nonasbestos transmission paper and cooling fills
are not available.
Production volume—Little information is available on the production
volumes of substitute products for specialty paper.
COMMERCIAL PAPERS
Included under this heading are the following types of products
e general insulation paper
• muffler paper
e corrugated paper
Only small amounts of asbestos muffler paper are now thought to be produced
and asbestos corrugated paper is no longer believed to be manufactured.
Asbestos Product
Special Qualities—
Asbestos is used in commercial papers because of its resistance to fire
and corrosion. It provides commercial papers with the strength and durability
needed for numerous applications.
Commercial asbestos paper exhibits fine durability properties, allowing
it to meet Federal Specifications requirements. For example, commercial grade
41
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paper is good for temperatures up to 316°C or 427°C where loss of strength is
not critical. Nonburn paper is suitable for continuous service at
temperatures of 316°C, and doublex asbestos paper has high wet strength and a
slightly elevated temperature limit of 427°C (or 649°C where some
embrittlement and loss of strength is not critical).
Nearly all of the current production of commercial asbestos paper falls
into the subclass of general insulation papers. Types of insulation available
include:
• Commercial Grades; A medium length fiber paper with minimum 95
percent fiber content. Available in 10, 12, 16, 32, and 64 lb/100
sq. ft. weights in widths of 18, 36, and 72 inches in 25, 50 and 100
Ib rolls. Suitable for most general purposes in industry. Good for
temperatures up to 316°C or 427°C where loss of strength is not
critical. Meets Federal Specification HH-P-1784.
• Nonburn Paper: A medium length fiber paper with high fiber
content. Available in a weight of 4 lb/100 sq.ft., 36 inches wide
in 50 and 100 Ib rolls. Suitable for continuous service at
temperatures of 316°C.
e Long Fiber Paper; Made with a high-grade, long asbestos fiber;
minimum fiber content 98 percent on 6 Ib and heavier papers. For
use as a thermal insulation, gasketing, and base sheet for
saturating.
« Doublex Asbestos Paper: Completely inorganic; will not burn, char,
or smoke. Has high wet strength. Available in a weight of 10
lb/100 sq. ft., 36 inches wide in 50 or 100 Ib rolls. Developed for
use as a neon sign pattern paper. Also used as liner for foundry
funnels and pouring gates. Temperature limit 427°C or 649°C where
some embrittlement and loss of strength is not critical.
Product Composition—
The commercial asbestos paper category encompasses a broad range of
papers that differ primarily in weight and thickness. The product is normally
composed of 95 to 98 weight percent asbestos fiber and 2 to 5 percent starch
binder.3 Short and medium grades of chrysotile are used.
Muffler paper contains a very high percentage of asbestos fiber and only
a small percentage of starch binder. The surface of the product is waffled or
indented.
Corrugated asbestos paper is a commercial paper product corrugated and
cemented to a flat paper backing, sometimes laminated with aluminum foil.
Corrugated paper is manufactured with a high chrysotile asbestos content and a
starch binder.
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Uses and Applications—
The principal use of commercial asbestos paper is to provide maximum
insulation against fire, heat and corrosion with minimum product thickness.
Commercial papers fall into three subclasses based on use: (1) general
insulation papers, (2) muffler paper, and (3) corrugated paper.
General asbestos insulation papers have the following major uses in steel
and aluminum factories:
• Thermal insulation in annealing furnaces
• Trough lining for smelting process
• Refractory lining
• Expansion joints between brick layers of furnace
• Backing insulation
• Insulation to catch molten metal drippings and hot metal
In foundries, asbestos paper is used as mold liners, as refractory
liners, and as expansion joint material on induction coil heaters. In the
glass/ceramic industry, commercial paper is used for kiln insulation, linings,
and as a separator for hot and cold flat glass sheets. GAF Corporation makes
a grade of commercial paper that is laminated to steel decks for
fireproofing. ^ Johns-Manville sells commerical paper to a large electric
parts and appliance manufacturer for electrical insulation not requiring the
high purity of asbestos electrical insulation. Commercial paper is used for
dielectric and thermal protection of transformers for fluorescent tubes^^
and in mercury vapor lamp housings.
Muffler paper is used by the automotive industry primarily in the
construction of catalytic converters for exhaust emission control systems.
The paper is applied as a wrap between the inner and outer skins of the
converter or muffler for two reasons: First, it maintains the high
temperatures required for pollution control within the converter reaction
chamber; second, it insulates the outer skin, preventing it from becoming too
hot. In a less common application, muffler paper is used as a heat shield
between the muffler and the automobile body.3
Corrugated asbestos paper is used as a thermal insulator for pipe
coverings, block insulation, and specialty panelings- Applications of
corrugated asbestos paper include appliance insulation up to 149°C, hot-water
and low-pressure steam pipe insulation, process line insulation, and panel
insulation, such as paneling in elevators.5>/l,78
It should be noted that a large portion of the commercial paper produced
is sold to distributors and/or converters who, in turn, sell to their
43
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customers. Thus, due to the large number of people involved in the production
and conversion process, it is nearly impossible to identify all of the
specific end uses which might arise.
Asbestos Product Manufacturing Summary—
Manufacturing process—General asbestos insulation and muffler paper are
manufactured on conventional papermaking machines producing sheet rolls or
tapes as end products. The manufacturing operation for corrugated paper also
employs conventional papermaking equipment but adds a corrugation machine to
produce the desired corrugated molding of the paper suface.
Name and number of manufacturers—Commercial paper is manufactured in the
United States by Nicolet (Ambler and Norristown, PA) and Celotex (Lockland OH,
and Linden, NJ). GAF and Johns-Manville were due to discontinue the
manufacture of commercial paper in 1980.8,18 Commercial asbestos paper is
normally sold by the manufacturer to independent distributors, converters and
some original equipment manufacturers. There are about 300 distributors
and/or converter companies in the U.S.3 Two of the larger
distributor-converters are Grant Wilson (Chicago, IL) and Janos Industrial and
Insulation (Moonachie, NJ). Original equipment manufacturers include General
Electric, Ford, and Caloric.79
Muffler paper is made by Celotex in Lockland, OH. At present only small
quantities are being manufactured, primarily for export.5»71 Corrugated
paper was formerly produced by Johns-Manville Corporation and Nicolet
Industries but is not being manufactured at present, apparently due to the
availability of reasonably priced substitutes and customer desires to avoid
products containing asbestos.
Production volumes--As noted above, it is believed that corrugated paper
is no longer produced3' '^- and asbestos muffler paper is only produced in
small amounts.
In 1975, 3500 tons of asbestos were used to manufacture asbestos muffler
paper, making it the fastest growing segment of the asbestos paper industry at
that time. It is also estimated that about 3500 tons of asbestos went into
corrugated asbestos paper.3 By 1977, corrugated asbestos paper demand had
declined to 2500 tons.80 Presently, the entire category of general
commercial insulation papers are believed to consume 1170 tons annually;
individual muffler and corrugated paper production figures are not available,
but production volumes are believed to be minimal.
Substitute Products
Methodology—
Search strategy--Information on asbestos commercial papers was gained
both from contact with industry representatives and literature review.
-------
Summary of contacts—
• Mr. E. Cavicchio, GAF Corporation, Erie, PA, August 1979
« Mr. B. Reznick, Cotronics Corporation, Brooklyn, NY, March 1980
• Representative, Johns-Manville Corporation, Denver, CO, March 1980
e Representative, Celotex Corporation, Linden, NJ, March 1980
Special Qualities—
Substitutes which may be used in place of asbestos commercial paper
include ceramic, cellulose and fiberglass products. Applications vary, and
those products demonstrating high temperature resistance appear to lack the
ability to couple this with sustained strength. Ceramic paper can be used at
higher temperatures than asbestos; it can withstand a continuous temperature
of 1260°C. At 1760°C it will melt.81 However, it has not been proven to be
as strong or resilient as asbestos paper. Cellulose and fiberglass papers
generally lack the heat resistance and dimensional stability required for heat
and flame resistance.
A Johns-Manville product, called Cerafiber, may be used for general
insulating, and flameproofing applications to 1316°C. These low-density
papers do not store heat and thus may be heated or cooled almost
instantaneously. In addition, they possess unusually low thermal
conductivitiy, can be safely cycled from cryogenic temperatures to their
highest operating temperature, and offer outstanding tensile strength,
flexibility, and resiliency. They can be easily die-cut, rolled, folded,
bent, or wrapped.°^
(Si
In addition, Fibercoat^ by Textured Products, Inc. is suggested as a
possible alternative for some commercial papers, including aircraft engine
exhaust system wrap and furnace linings.39 Detailed information on
Fibercoat may be found in the secton titled "Electrical Insulation."
Product Composition—
Substitutes may be made from ceramics, cellulose or fiberglass.
Cotronics' ceramic paper is made from high purity refractory fibers.°^
Despite the widespread public belief that ceramic products are hard and
brittle, these ceramic papers can be cut with scissors, folded, wrapped,
rolled and formed into free standing shapes. The J/M product is also made
from pure refractory fibers; the binder content varies from 5-6 percent
depending upon the type of paper.82
Uses and Applications—
Commercial asbestos paper is primarily used as a general insulation for
heat and flame applications. For many of these applications, ceramic paper
could be substituted for asbestos paper, but the cost would be greater.
45
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Specifically, ceramic paper can be substituted for asbestos papers in the
following applications:^6,83 (^) liners, covers, and insulation for the
aluminum and steel industry; (2) molds, liners, and insulation in foundries;
(3) similar applications in the glass making industry; (4) fire protection
barriers; and (5) welding insulation. Domestically, ceramic paper has already
replaced asbestos paper in mufflers and catalytic converters.5>71 it is
being used in kiln and furnace construction, high temperature filters, lab
ovens, arcing prevention, high temperature gaskets, instant crucibles,
acoustical insulation (inside mufflers), expansion joints, casting alloys,
lamphouse insulation, and chromatography. Glass, ceramic, chemical,
electrical, metal, optics, welding, and instrumentation applications have all
been developed.-*®
Ceramic materials display advantages over asbestos commercial papers,
primarily an ability to withstand a greater temperature range and a lack of
any identified negative health effects. Yet they also have disadvantages
including greater cost, and second, less dimensional stability.
Substitute Product Manufacturing Summary—
Name and number of manufacturers—At present, the only commercially
available alternatives to commercial asbestos paper are ceramic mineral fiber
papers and glass papers. The ceramic papers are marketed by such companies as
Carborundum Corporation (Niagara Falls, NY), Cotronics Corporation (Brooklyn,
NY), and Johns-Manville (Denver, CO). The J/M product comes in rolls of 12
in. , 24 in. , and 36 in.28
Production volume—The exact production volume of products substituting
for asbestos commercial paper is not known. However, it is known that ceramic
paper has already replaced asbestos paper in many muffler and catalytic
converter applications domestically.->> '»8
ELECTRICAL INSULATION
Asbestos Product
Special Qualities—
Asbestos is used in electrical paper insulation because of its high
thermal and electrical resistance, which permits the paper to act effectively
as an insulator and protects the conductor from fire. However, despite the
special properties of asbestos utilized in electrical insulation, it appears
that substitutes are now available which retain these properties while
reducing the associated risk of asbestos fiber exposure to employees.
Product Composition—
The composition of absestos electrical insulation paper varies with the
intended application but generally contains chrysotile asbestos fibers and
cellulose bound with latex polymers. Small amounts of amosite and tremolite
are also used occasionally. Quin-T's high purity asbestos paper uses
chrysotile fibers obtained from Johns-Manville, chemically treated to remove
impurities (trace elements).-'-
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Electrical insulation is frequently impregnated with solid resins to
increase dielectric strength, improve mechanical properties .and provide
moisture-proofing characteristics offsetting the hygroscopic property of
asbestos fiber. Depending upon the expected temperature of service,
resin-bonded papers or boards may use phenol, formaldehyde, polyvinyl acetal,
epoxy, or silicone resins. Glass or other fibers may also be present.->0
Uses and Applications—
Asbestos is widely used in the electrical industry in the form of paper,
tape, cloth, and board. It may be applied as a felted material or as a filter
for natural and synthetic insulating resins. The largest use of asbestos
electrical paper is as insulation for dry transformers, for layer insulation,
and cross-over insulation.°^>85 Asbestos paper tapes are used as a general
wire wrap, as turn insulation for various industrial equipment, and to a much
lesser extent, in appliances. Electrical equipment subjected continuously to
high temperatures is the most typical use of asbestos paper insulation. For
example, electrolifting magnets used in steel mills to pick up and move
billets have asbestos paper as turn insulation"^ and steel mill drive motors
have asbestos insulation. Asbestos materials are not suited for high-voltage
insulation nor for high-frequency insulation, due to a high dielectric loss
even when dry. Therefore, their main electrical use is in low-voltage, high
temperature situations, and for confinement of arcs.^0
Appliances that use asbestos papers for wire insulation include stoves
and toasters. The extent to which asbestos paper is currently used for these
applications is not clear, but use has dropped significantly due to asbestos
concern from manufacturers and the availability of substitutes. For example,
toaster boards made with asbestos in the past are currently being made with
mica-board or some other substitute material.
Asbestos paper is used in grade A industrial laminate for low-voltage
applications, such as household current.°° Other uses include low-voltage
transformers, armature slot wedges, furnace parts and domestic heating
equipment.^8 Industrial laminates generally refer to a class of electrical
insulating materials produced by impregnating fibrous webs of materials with
thermosetting resins and then fusing multiple layers together under high
temperature and pressure. Asbestos paper is only one of many materials used
to make these laminates; other materials include cellulose paper, cotton,
nylon, and glass. Grade A paper currently has only limited applications for
thermoset resin products.87,88 ^he sheets may be stamped or fabricated into
specialty spacers and washers used in small appliances for electrical and
thermal insulation where temperatures are too high for cellulose based
laminates.
Asbestos Product Manufacturing Summary—
Manufacturing process—Asbestos electrical insulation paper is formed on
conventional papermaking machines. The paper products include rolls, tapes,
tubes, or sheets, all of various thicknesses and various sizes. Electrical
papers are sold to fabricators in the electrical and electronics industries
who sH6raEa&e the paper with resin to produce an industrial laminate.
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Name and number of manufacturers—Asbestos paper for electrical
insulation is currently manufactured by the Quin-T Corporation (Tilton, NH),
formerly owned and operated by Johns-Manville.^ Nicolet Industries
(Norristown, PA, and Hamilton, OH) no longer produces asbestos electrical
paper.^ The- Norristown, PA, plant has closed.'
Production volumes—Electrical insulation accounts for approximately 0.4
percent of the asbestos consumed in the paper products category annually,
placing it sixth in asbestos consumption, behind flooring felt, roofing felt,
gaskets, pipeline wrap, and millboard. Estimated consumption in 1980 for this
category is 360 metric tons.l
Substitute Products
Methodology—
Search Strategy—Both a literature review and telephone interviews with
substitute manufacturers were used to discover more about asbestos electrical
insulation and available or potential replacement products.
Summary of contacts—The following companies were contacted in
researching this topic:
o Mr. J. Hayman, DuPont, Wilmington, DE, July 1979
• Sales Secretary, Carborundum Corporation, Niagara Falls, NY,
September 1979
c Mr. N. Highes, Quin-T Corporation, Tilton, NH, July 1979
« Mr. R. Wilmore, National Electrical Manufacturing Association
(NEMA), Washington, DC, August 1979
• Mr. W. Lair, NVF Company, Yorklyn, DE, August 1979
• Mr. L. Heid, Manning Paper Company, Green Island, NY, March 1980,
and Mr. S. Wong, July 1979
• Mr. S. Delheim, Crane and Co., Inc., Dalton, MA, March 1980
e Mr. B. Hardy, DuPont, Wilmington, DE, September 1979
a Mr. A. W. McGowen, Masonite Corporation, Laurel, MI, February 1980
Special Qualities—
Substitute products presently available include DuPont's Nomex paper,
Carborundum Corporation's ceramic Fiberfrax paper, Manning Paper's Manniglass,
and Masonite's Benelex 402. in addition, a product called Fibercoat is
produced by Textured Products, Inc., and, as its main use currently appears to
be in this category, it will be discussed here.
48
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Nomex papers have qualities of thermal stability, flame resistance, and
electrical properties that allow it to compete directly with asbestos paper.
Underwriters Laboratories (UL) recognizes Nomex paper as suitable for
continuous use at temperatures up to 204°C; it can also be used for short
durations at much higher temperatures."^ Other polymeric materials used as
cable coatings may be suitable for temperatures as high as 260°C and can
withstand soldering temperatures for short time intervals.50
Fiberfrax 110 ceramic paper exhibits good dielectric strength, is
somewhat stiff, and can be cut and handled easily. Ceramic fiber cloth has
excellent temperature resistance, operating well up to 524°C.
Glass fabrics like Manniglass, are not affected by temperatures up to
204°C. At 3A3°C, however, their strength is halved. Glass fabrics wrapped
tightly onto wire and treated with resins are more vulnerable to abrasion than
most other wire coverings and are not suited for applications involving severe
flexing.
Benelux 402 is a mechanical-electrical grade able to withstand abrasive
action, acidic conditions and steam cleaning.^9 it weighs half as much as
aluminum and one-sixth as much as steel. It also holds precise dimensions
despite temperature and humidity fluctuations.
Special qualities of Fibercoat, a knitted glass product, include its
ability to fuse with ceramic coatings (applied for industrial uses), becoming
a dense, true ceramic at 1093 C (2000°F) or greater,* with no combustion,
toxic fumes or gases. It can also be coated with abrasion resistant materials
such as urethane, while still retaining fire retardant and insulating
properties. Fibercoat can be produced in an essentially dimensionally stable
configuration, or with a built-in stretchability of as much as 5 percent.
This stretchability is vital for important uses such as spiral-wrapping of
pipe and electrical cables. Fibercoat can be made considerably more flexible
than typical asbestos weaves. Insulating factors of Fibercoat vary with the
type of knit and the thickness of the inorganic coatings; they are, however,
reported to be comparable or superior to asbestos of similar thickness and
cost. Fibercoat, like asbestos, will resist flame temperatures of 1093°C
(2000°F) or more and its inorganic binder is not affected by organic solvents,
most acids, or water. In addition, Fibercoat can be tailored to withstand a
temperature of 2200°C (4000°F) or higher, at a higher cost. One example of
this is to knit Kevlar, then coat with a high-alumina ceramic mix. Fibercoat
maintains its heat insulating ability after prolonged exposure to flame in the
1200°C (2200°F) range, where, after 3-5 minutes of exposure, it changes to a
ceramic as described, and maintains this structural integrity indefinitely.
Even if the fire is brought under control with water, foam, or Halon gas, the
strong, but now brittle, Fibercoat wrapping protects and insulates the cable.
There is no afterburn with Fibercoat and no propagation of flame by the
material.-^"
*Glass loses some strength at 315-430°C (600-800°F).
49
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Other specific properties of Fibercoat include the fact that it does not
absorb water, either before or after exposure to high temperatures, although
it does pass water vapor in small amounts in most applications. For toxicity,
no material used in Fibercoat is considered highly toxic. The components
remain tightly bound together in use. Cleanup after a fire is facilitated by
the coating's tendency to pull cleanly away in dry chunks. Tensile strength
is reported to be fundamentally the same as the glass fiber from which it is
knit, which is superior to asbestos. Fibercoat can be laminated to some
substances, including ceramic cores. Hydrofluorous and phosphoric acid and
concentrated alkalis are the only substances Fibercoat' will not resist. It
does resist oxidation and reduction and all common organic solvents. Its
dielectric strength is similar to asbestos in 110/220V applications, and is
thought to be similar at much higher voltages but has not yet been tested.
Abrasion resistance is similar to asbestos weaves and paper, but it may not be
used in highly abrasion-resistant applications such as automotive brake
linings.39
Another potential substitute is wet ground mica, which meets ASTM
Standard Specifications D-607-42. Wet ground mica is extensively used as a
dry powder and in various products due to its dielectric and heat resistant
properties.^O
Polyimide and polyethersulphone are also examples of high temperature
polymeric materials which may be used in place of asbestos. In addition,
ceramic fibercloth, tape or sleeving, used with glass filament inserts (to
maintain high temperature strength) may be used in cable and wire
insulation, "-l-
Product composition—
Nomex paper is an aramid paper composed mostly (85 percent) of a highly
aromatic polyamide synthetic material formed on a Fourdinier machine."2 xhe
smallest fiber size used in Nomex paper is 1/4-inch long. Fiberfrax® is a
homogeneous product composed primarily of silica and alumina held together
with an organic binder."-'- Benelux 402 is a dense lignin-resin cellulose
laminate. Manniglass is a glass fabric. Fibercoat is a fabric of knitted
(versus woven) glass, representing what is reported to be one of the world's
few production uses for knitted glass in a process developed by Textured
Products, Inc. The glass fiber is coated with a proprietary blend of ceramic
and inorganic binders.39*
Uses and Applications—
For dry transformer insulation, Nomex can directly substitute for
asbestos paper; it already enjoys a high market share. Nomex papers have also
replaced asbestos as wire and turn insulation for most industrial motor and
generator applications.
Substitutes are also available for industrial laminates using asbestos
no
paper. Nomex paper can be used to prepare industrial laminates5-5 and glass
papers are currently being used to replace asbestos in various laminated
products."^
*The U.S. Patent for this material was applied for in September 1979.
50
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Carborundum Corporation stated that their ceramic paper, Fiberfrax, can
be used as dielectric and thermal insulation for transformer coils.->6 The
extent of any commercial application of Fiberfrax for this purpose is not
clear.
Benelux 402 has been used for insulation barriers in air insulated
switching and control devices. Its properties make it usable in a wide range
of utility-oriented electrical apparatus.^9
Fibercoat has been most extensively tested for use in low-voltage cable
as insulating and fireproofing wrap. One major cable manufacturer has found
that Fibercoat provides excellent protection for 25 pair 24 AWG PVC-insulated
control cable. It can be wrapped around wire as small as 14 AWG equivalent,
and can also be used to insulate phone wire. It is also approved for use by a
major chemical company to protect 300/600V underground cable (see Pipeline
Wrap section), and is speculated for use in other applications noted briefly
in other sections of this report.39
Wet ground mica is used in the rubber industry as an insulation powder
and compounds for electric wire and cables."*^
Substitute Product Manufacturing Summary—
Manufacturing process—Glass fabrics of all kinds (cloth, tape, cords,
tubes) may be woven from yarn and used in resin-bonded laminates as a
substitute for asbestos. For molded or hand-load composites, glass chopped
strand mat may be used; in high temperature windings, glass fiber is wrapped
tightly onto wire and treated with suitable resins.91
Benelux is made from clean wood chips reduced to fibers by a steam
explosion process. Unwanted elements are driven off, leaving only cellulose
fibers and lignin, a natural bonding agent. After processing to refine the
fibers and form panels of controlled densities, thicknesses and sizes, the
panels are placed in steam heated ultra high pressure presses where the fibers
and lignin are welded to form the hard, smooth laminate.^9
Fibercoat can be produced in a variety of configurations ranging from
ribbons less than half an inch wide and as thin as 10 mils, to 72 inch wide
sheets as thick as a tenth of an inch. The same technology used to knit the
glass fiber can also be used to knit more temperature-resistant substrate
materials, such as polyimides, with appropriate high-temperature resistant
coatings. In addition, Fibercoat can be built into rigid structures much as a
fiberglass and resin composite can be. When coated, the coatings such as
urethane, polyvinyl chloride and acrylics form mechanical rather than chemical
bonds with the woven glass.^9
Wet ground mica is made most often from Muscovite type mica
[K.2Al4Al2Si602o(OH)4 ], selected, blended, and treated to obtain
maximum color, brightness and purity. While several types of wet ground mica
are produced, nominal 325 mesh is most widely used. This is approximately 46
percent silica, 36 percent alumina, 10 percent potassium oxide, and 2 percent
ferric oxide.
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Name and number of manufacturers—Substitute product manufacturers
include: DuPont (Nomex papers), Carborundum Corporation (Fiberfrax), Manning
Paper Company (Manniglass), Masonite (Benelux 402) and Textured Products, Inc.
(Fibercoat).
Production volume—The exact production volumes of substitute products
are unknown; specific information Js proprietary. However, it is known that
Nomex paper is produced at the rate of several million pounds per year and is
readily available.93'94
BEVERAGE AND PHARMACEUTICAL FILTERS
Asbestos Product
Special Qualities—
Asbestos is used in filters because it has an exceptionally large surface
area per unit of weight and a very unusual natural positive electrical
charge.95 This positive charge is very desirable for removing particles
from beverages as the particles are usually negatively charged. Although
other substances may be used as filter materials, asbestos appears to provide
one property required by some beverage manufacturers which its competitors
lack—that of the removal of haze from liquid beverages. The filtering
efficiency of nonasbestos sheets is considered about equal to that of
asbestos, aside from haze removal capabilities. Substitutes for asbestos
filters are readily available and will likely undergo further improvements as
they are developed. As far as is known, substitutes seem to equal asbestos in
durability and service life.
Product Composition—
The major difference between asbestos beverage filters and other asbestos
paper products is the formula. Asbestos beverage filters may contain, in
addition to asbestos, cellulose fibers, various types of latex resins and,
occasionally, diatomaceous earth. The asbestos content varies from a high of
50 percent for pharmaceutical filters to as low as 5 percent for rough
filtering applications. In general, the higher the asbestos content, the
better the filtering qualities. The grade of asbestos used is a very
high-purity grade (longer fiber; thus in the lower grade numbers) obtained,
when available, from Arizona mines; a usable grade is also available from
Canada. This particular high-purity grade of chrysotile must be free of trace
minerals such as iron and calcium.
Uses and Applications—
Asbestos filter sheets are primiarily used by the beer, wine, and liquor
distilling industries to filter (remove) microorganisms, fine, or very fine
solids from liquids. In the beverage industry, there are several filtration
steps; asbestos filter papers have most commonly been applied for "sterile"
filtration, the complete removal of all yeast cells and microorganisms, both
aerobic and anaerobic, that might have survived previous filtration.9"
Asbestos filters are also used for haze clarification, removing cloudiness
from the liquid product and giving it a sparkling clarity.
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At present, about 30 percent of the wine industry, 10 percent of the beer
industry, and 25 percent of the distilling industry use some form of asbestos
filtration."' Asbestos filter paper is also used for specialty applications
In the cobmeties nnd Pharmaceuticals industries and for the filtration of
various fruit juices, such as apple juice.
Asbestos Product Manufacturing Summary—
Manufacturing process—Asbestos filter paper is made on a conventional
cylinder or Fourdrinier papermaking machine. Because demand for this product
is low, the machine is used to produce beverage filters infrequently; for the
most part, the machine is employed to produce more popular products.
Name and number of manufacturers—The main companies manufacturing
asbestos filter paper as part of their product lines are listed in Table 8.
TABLE 8. MANUFACTURERS OF ASBESTOS BEVERAGE
AND PHARMACEUTICAL FILTERS
Alsop Engineering98 Milldale, CT
Cellulo Co." Fresno, CA
Sandusky, OH
Ertel Engineering100 Kingston, NY
Filter Products Co. Richmond, CA
(H&K Filters)
For the companies listed, asbestos filter production represents only a
small fraction of their total business. For example, Filter Products Co.
makes asbestos filters only once or twice a year for specialty
customers.I-01 Cellulo Co. is the largest domestic producer of asbestos
filters, supplying much of the amount needed by the beverage and
pharmaceutical industries."'
Production volumes—Asbestos filters (beverage and pharmaceutical) are a
subject of the larger asbestos specialty paper category. About 30 metric tons
of asbestos are used in filters; most of the remainder of the metric tons used
in specialty papers goes into cooling tower fill and transmission paper.2
Because such a small amount is produced, most producers of asbestos filters
make filters only once or twice a year, then revert to other products that are
their main earning staples. Thirty metric tons per year is a significant
decline from the consumption levels in the late 1960s and early 1970s when
over 900 metric tons of fiber were being consumed; projections call for a
virtual disappearance of asbestos filters.
Substitute Products
Methodology—
Search strategy—Source material for asbestos filters consisted of
literature sources supplemented by industry contacts.
53
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Summary of contacts—The following companies and individuals were
contacted during preparation of this section:
• Mr. Don Wheaton, Cellulo Co., Fresno, CA
• Mr. Rumain, Plant Sales Representative, Cellulo Co., NJ
• Mr. Frank Lavery, Mr. Hallet, Ertel Engineering Co., Kingston, NY
9 Mr. John Gusmer, President, Cellulo Co., Waupaca, WI
• Mr. Held, Filter Products Co., Richmond, CA
• Company Representative, Alsop Engineering, Milldale, CT
Special Qualities—
Substitute fibers which may be used in place of asbestos fibers in
filters include cellulose and glass. According to industry sources, these
nonasbestos substitutes have the durability of asbestos filters, but above
grade 70 (an indication of filter porosity), asbestos filters are more
efficient.102,103 xhe service life of any filter is difficult to estimate
because of its dependence upon a variety of parameters, including viscosity,
temperature, color, clogging rate, and foreign substances. For example, Ertel
Engineering's filters (both asbestos and nonasbestos are made) are reported to
Last longer filtering white wine than red wine.1*^ The Cellulo Company's
Cellupore nonasbestos filter pads have a shelf life of 1 year versus asbestos
filters which are believed to have a slightly longer life.
Chemical treatments can be used to affix a positive electrical charge to
substitute fibers, but asbestos filters have other characteristics which have
not as yet been incorporated in these filter substitutes. To date, asbestos
filters have been able to be made with lower porosity than nonasbestos
filters. Cellupore filters (made from cellulose) are available in a variety
of "tightnesses" or porosities up to grade 70, but asbestos filters are
available through grade 100.10^ Further, nonasbestos filters absorb more
liquid than asbestos filters and thus operate at a lower throughput. Evanite
literature describes their product in terms of air resistance, air
permeability, chemical resistance of the C or B glass fiber used, acid and
alkaline resistance and thermal resistance, apparently with satisfactory
results.
Product Composition—
A nonasbestos beverage filter made by Filter Products Company of
Richmond, CA, is made from two types of specially prepared cellulose fibers,
three types of diatomaceous earth and melamine resin, -^l As mentioned
earlier, the fibers substituting for asbestos must be chemically treated to
give the filter the desired positive charge.
Evans Products Company, Forest Fiber Products Group in Corvallis, Oregon,
produces Evanite glass fiber from either a standard borosilicate glass
54
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composition or a specially formulated acid resistant grade with significantly
higher silica content. Formulations are comprised of various combinations of
sand, feldspar, Hodn ash, borax, dolomite, limestone, barium carbonate, and
zinc oxide. These ingredients are first introduced into a glass furnace for
melting and glass conditioning. The glass stream then passes through an
electrically controlled platinum bushing which regulates the flow into a
rotary fiberizer or "spinner." The primary fibers are immediately attenuated
by a blast of hot gas into the desired fiber diameter. They are then
collected, under partial vacuum, on a moving screen located within a forming
chamber. From here the fibers are removed, compacted to a uniform weight, and
'packaged at a specific density to minimize fiber breakage. The Evanite fiber
grades have been developed for use on conventional papermaking equipment to
deal with differences in drainage rates, drying time, and shinkage
characteristics. *-Q->
The Cellulo Company produces two lines of nonasbestos beverage filters in
addition to their asbestos and acid-washed cellulose filters. One, trade
named Cellupore®, is made primarily from cellulose fibers. The other, the 700
Series, combines cellulose, nonfibrous filter aids, and an absorptive binder
system. Each is graded by porosity from 10 to 70 in increments of 10, but
asbestos filters can attain higher standards. Asbestos filters are available
graded from 70 to 100 in increments of 5. All beverage filters are inert,
chemically pure and conform to Federal Food and Drug Regulations for food and
beverages.
Ertel Engineering manufactures filters in 360 different sizes out of
asbestos and cellulose fiber, cellulose and diatomaceous earth, or a mix of
cellulose from wood pulp and paper. Each product composition results in a
different porosity and density level.102
Major purchasers of nonasbestos beverage filters are the pharmaceutical,
cosmetic and food industries. The fiber size distribution in filters used in
these industries is not known. However, grades used vary with the intended
application and higher grades contain shorter fibers.
Uses and Applications—
Nonasbestos substitute filters can be used almost interchangeably with
asbestos filters in most applications. Cellupore filter pads are available in
sizes to fit virtually all commerical filter holder assemblies, including
plate and frame assemblies and stacked disc holders. Like asbestos filters,
the substitutes have high wet strength and ca-n clarify, polish, and sterilize
a wide variety of liquids, including acids, alkalis, antibiotics, antiseptics,
aperitifs, beer, wine, whiskies, cider, cosmetics, detergents, drinking water,
fruit juices, hair tonics, inks, insecticides, perfumes, vaccines, and
photographic solutions. Applications for Evanite include fluid and air
filters, surgical masks, industrial respirator media, and high efficiency
thermal and accoustical insulation.
55
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Substitute Product Manufacturing Summary —
Name and number of manufacturers — Tv/o manufacturers of nonasbestos
beverage filter products were contacted:
0 Cellulo, Inc., NJ and WI, and
• Ertel Engineering Company, Kingston, NY
Evans Products Co. , Corvallis, Oregon, is also known to sell its
nonasbestos product, Evanlte, to AMF, which may manufacture nonasbestos
beverage filters. ^-^^
Production volumes — The production volumes of nonasbestos beverage
filters are not known; however, they appear to dominate the beverage filter
industry at present.
COST COMPARISON
Flooring Felt
Costs of flooring felt vary widely since the number and type of
substitutes themselves differ greatly. The range of substitute costs is
perhaps the greatest of any of the paper products, and rests very much upon
consumer taste and choice. Substitutes which are less expensive than asbestos
and those more expensive are both available. An exact cost comparison for
each substitute product is not included in this report. However, it is
reported that the Lextar product under development currently costs 10-15
percent more than asbestos felt; Lextar is working actively with the major
commerical asbestos felt producers to reduce this cost to an equivalent
asbestos
Roofing Felt
Table 9 provides two cost comparisons. First, there is a comparison of
the basic roofing material costs of organic, asbestos and fiberglass felts,
and the membrane material. Since rolls come in different sizes and the number
of layers installed on the roof will vary, the basic unit of comparison in
this table is the square, a 100 square foot area of roofing. In terms of
material cost per completed square, only organic felt is less expensive than
asbestos. More meaningful comparisons, however, are the costs for installed
units. Asbestos and fiberglass are nearly equal in quality and durability,
but a fiberglass square is 5.6 percent more expensive than a comparable
asbestos square. A membrane roof is 13 percent more costly than an asbestos
unit. Thus although the membrane roofing is considerably more expensive than
any of the felts, the considerable savings in labor and other materials such
as tar or asphalt is evident in the comparisons between material and installed
costs. A company that manufactures both conventional organic asphalt roofing
and the membrane systems estimated that the cost difference between the two
systems, installed, is only 5 to 10 percent
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TABLE 9. ROOFING COSTS11'12>21>106»107
Retail
cost
per roll
($) Squares
Organic 10.00 4
felt
Asbestos 23.50 4
felt
Fiberglass 28.50 5
felt
Single-ply 35.70 1
membrane
Single
square
(one layer) Material cost
($) per square ($)
2.50
5.75
5.60
35.70
7.50
(three layers)
11.50
(two layers)
16.80
(three layers)
35.70
(one layer)
Installed cost
per square ($)
Range Average
100-160 126.00
115-160 132.50
110-160 140.00
150.00
Beater-Add Gaskets
Currently, substitutes for asbestos gaskets are more expensive than the
asbestos product. Both ceramic and teflon gaskets fit this description. The
cost of Cotromics Corportation's ceramic paper varies depnding on the desired
thickness, from 20 to 50 cents per square foot.33 One-eighth inch thick
Fiberfrax is available for 50 to 85 cents per square foot or 3.5 to 5.9 mils
per square inch with the exact price dependent upon the quantity
ordered.1^ Comparable teflon gaskets may be purchased for about 8.5 cents
per square inch placing them at the high end of the cost scale.35
Hollingsworth and Vose reports, however, that, although currently more
expensive, as substitute products obtain wider acceptance and use,
manufacturing volumes will increase, thereby diminishing the price gap between
the materials.36
Pipeline Wrap
In future years, it is thought that the cost advantage of fiberglass
systems will improve relative to asbestos pipeline use, making it more
competitive with the asbestos product. More specific information, as well as
cost information for plastic coatings and extruded coatings of epoxy resin was
not available through industry contacts.
Millboard
Substitutes discussed here generally have insulating qualities equal or
superior to asbestos board, but most have significantly higher prices.
Vermiculite boards, although meeting required specifications, are generally
57
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inferior to asbestos products and cost about 30 percent more. Cobalt rollers
have been used as a millboard substitute in steel heat treatment applications,
but are considerably more expensive than comparable asbestos products--*0
Table 10 provides a price comparison between asbestos millboard and the most
frequently proposed substitute products. Johns-Manville has been working to
develop a product suitable for temperatures up to 816° to 870°C to sell for 15
percent less than their Ceraform 102. It should be closer to a direct
substitute for asbestos millboard.
TABLE 10. COST OF ASBESTOS MILLBOAPD AND SUBSTITUTE PRODUCTS—
$ per square foot (square meter)
Thickness
(inches)
1/8
1/4
1/2
Asbestos4"
0.32
(3.55)
0.61
(6.75)
1.15
(12.75)
Pars
No. 948
0.86
(9.55)
1.44
(16.00)
2.82
(31.35)
Johns-
Manville 49
Ceraform 102*
0.96
(10.65)
1.16
(12.90)
1.63
(18.10)
Carborundum Fiberfrax32
Dur aboard
-
-
2.16
(24.00)
Hotboard*
_
-
1.30
(14.45)
GH Boardt
-
3.08
(34.20)
-
*Price for 1000 ft2 or more.
+Price for 75 ft2 lots.
Commercial Papers
Ceramic paper is a great deal more expensive than asbestos paper,
averaging 5 to 10 times as costly. Cellulose and fiberglass paper substitutes
such as Nomex by DuPont are also more expensive.
Electrical Insulation
While Nomex paper can replace asbestos paper in most electrical
insulations, the resultant price is higher. For most applicatons, Nomex
generally costs two to four times as much as asbestos electrical paper
Nomex is priced as follows for the four sizes of paper manufactured:
84
Thickness
(mil)
Price i/yd2
(*/m2)
3
5
8
10
1.84 (2.30)
2.92 (3.65)
4.40 (5.50)
5.47 (6.85)
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Fiberfrax is available in two thicknesses. Its cost varies in accordance
with the quantity ordered. Large volume purchasers can achieve a savings of
as much as 42 percent."1
Thickness Price Range
(inches) *
1/16 (62.5 mils) 2.70 - 4.59 (3.40 - 5.75)
1/8 (125 mils) 4.50 - 7.65 (5.65 - 9.55)
The cost of Fibercoat by Textured Products is comparable to woven
asbestos products, but slightly more than asbestos paper. The literature
cites a typical cost for 25 mil flexible sheets as 50-75 cents per square
foot.39
Polymeric materials used in cable coating are available at relatively
high cost, but may be justified by their ability to withstand high
temperatures, their durabiliy and their flexibility.^0
Mica is milled by a relatively costly, slow friction process.90
Sepcific cost comparisons are not available.
Electrolysis Cell Diaphragm
The membrane cell product by DuPont consumes 2540 KWh/metric ton of
chlorine as compared to 2270 KWh/metric ton for asbestos. With escalating
energy costs, the cost differential may be significant. Industry research is
directed at reducing this difference.
Cooling Tower Fill
Calbestos is somewhat less costly than its nonasbestos substitute,
"Veriscore," with product applications about the same. No substitutes for
asbestos transmission paper were identified.
Beverage Filters
Cellupore filters cost approximately 10 to 15 percent more than
comparable asbestos filters. No blanket statement applies to the Ertel
products. At present, the cost of asbestos is increasing rapidly (from
$365/metric ton in 1975 to $1090/metric ton in 1979), but so is the cost of
wood pulp, making it difficult to determine exactly how costs will compare
even in the short run.
Summary
Summarizing the substitutes cost data one notes that for virtually every
paper category the commercially available substitutes are more expensive than
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the asbestos product. The only exceptions to this rule are certain types of
flooring and organic felt roofing. For all other asbestos-containing paper
products, the substitutes cost from 5 percent to upwards of 40 times more than
the aubustos product they are intended to replace. This cost differential may
change (decrease) as the substitutes market matures, and production techniques
are refined. For the present, however, it appears that the conversion from an
asbestos-containing paper product to an available substitute would not be made
were there no other considerations except for cost; that is, based on cost
alone, the move to total replacement of asbestos products with substitutes
would be prohibitive.
CURRENT TRENDS
Flooring Felt
Although asbestos flooring felt is in a high consumption category, future
growth is expected to diminish,^ due to a stabilization of the product mix
because the changeover (which has been occuring in the recent past) from jute
backing to the newer asbestos backing, is nearly complete. This means that
the asbestos product has now replaced the jute in most every application.
From 1970 through 1975, growth of the asbestos backing was estimated at 14.8
percent annually, whereas the same source projects that the annual growth
through 1980 will be 5 percent and only 2.9 percent from 1980 to 1985. The
market currently (1979/80) backs this up with a small positive growth rate.
In addition, new substitutes to the asbestos product, particularly foam
cushion backings, backless sheet flooring, and new developments using Pulpex*
fiber are providing increasing competition for the asbestos flooring felt
market, indicating that there may well be yet another transitional growth
stage at some time in the future, with the development of suitable
alternatives•
Roofing Felt
Industry sources feel that the asbestos roofing felt market is currently
stable, but a decline is expected in the near future for two major reasons.
First, asbestos roofing is beginning to feel competitive market pressures from
fiberglass roofing, and, second, labor unions and the construction industry
are becoming more apprehensive about using asbestos products. Fiberglass has
many of the same technical advantages and characteristics of asbestos and is
less expensive for initial installation. Furthermore, fiberglass requires
less saturation than asbestos and as petroleum and asbestos prices climb, the
cost differential between fiberglass and asbestos roofing will shift more and
more in favor of fiberglass. However, asbestos roofing is considered more
durable than fiberglass, possibly making asbestos more cost effective in the
long run.
*This is expected to be a future possibility, pending present testing results.
Pulpex is also currently used in other paper products such as filter and
decorative papers, thermoformable paperboards, and corrugated paperboard.
More information on PUlpex may be found in the Sealants section of this
report.
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Arthur D. Little-^ expected demand for asbestos roofing to decline at an
average rate of 2.8 percent through 1980 and by about 5 percent from 1980 to
1985. Industry sources feel the actual decline will be slightly less.
Beater-Add Gaskets
Although only a marginal increase is projected for asbestos gasket
substitutes, 1980 reports indicate that this increase is ongoing. Industry
contacts^ pointed to the fact that substitutes are often not used by
industries due to ther expense, but if concern over the use of asbestos
products grows and substitute products obtain wider acceptance and use, this
attitude could change. Already, marketable substitutes have increased
markedly, as noted by industry comments to the Draft version of this report.
There have been tremendous changes in this area from late 1980 through 1981
and significant, large new families of materials do exist as replacements to
the asbestos product, although their cost is high.31
Pipeline Wrap
Saturated asbestos pipe wraps are presently the preferred corrosion
protection system for oil and gas pipelines due to their time-tested
durability and relatively low cost. However, the market for pipeline
corrosion protection is competitive and alternatives to asbestos felt are
available.
As might be expected, potential growth in demand for asbestos pipe wrap
(or substitutes to it) is a function principally of new pipeline construction
and availablility of competitive materials.3 New pipeline construction has
historically experienced rapid growth and this is expected to continue.
Competitive alternatives to asbestos wrap, which are becoming more available,
will most likely exert some downward pressure on the growth of the asbestos
pipe wrap market.
At present, most industry sources view the asbestos pipeline wrap market
as stable; however, in the near term, a slight downward shift of the market
can be expected, primarily due to the competitive pressures of the relatively
new fiberglass pipe wraps and new epoxy resins and extruded coatings that are
just becoming commercially available. Cost effectiveness still favors
asbestos pipe wraps; however, with the rapidly rising costs of asbestos fiber
and petroleum products (asphalt and coal tar), the advantage may shift away
from asbestos.
Millboard
Substitute millboard products have been developed to meet the variety of
temperature, corrosion, and other environmental conditions imposed on the
asbestos product. Thus, asbestos millboard production is not expected to
increase significantly in the future. The annual growth rate for asbestos
millboard and commercial papers is projected to be only 0.9 to 1.0 percent
through 1985,3 but it is anticipated that U.S. firms producing millboard
will cease production of the product as acceptable, economical substitutes are
61
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developed.^ Industry is likely to maintain minimal production capacity for
specific applications where alternatives are not available. Nonasbestos
products becoming available are generally in heat and flame protection
applications.
Commercial Papers
The overall growth rate for asbestos commercial paper is slightly
negative and is not expected to change, indicating that substitute products
will have an opportunity to establish themselves in this area. Asbestos
muffler paper has already been replaced by ceramic and glass papers in the
United States, apparently due to concern exhibited by automotive muffler and
converter producers about using asbestos-containing materials. As for
corrugated paper, the current outlook indicates that it may not be made in the
future. Substitute products like ceramic paper can replace asbestos
commercial paper in the future if the greater cost of such products is
accepted.
Electrical Insulation
Transformer manufacturers are constantly using more substitutes for
asbestos electrical insulation papers. Nomex papers are already extensively
used by electrical and transformer manufacturers,"^ while Fiberfrax and
other replacement industrial laminates are already on the market. Therefore,
the market for asbestos electrical paper is declining, although the rate of
decline is not known at present. The market for substitute products such as
Nomex paper has been steadily growing since it became available in 1965.^
Fibercoat, although developed through research begun in 1978 on fiberglass as
a potential fireproof upholstery and wallcovering fabric, is a relative
newcomer to replacement applications in electrical insulation. Nonetheless,
its qualities demonstrate that it is indeed another suitable substitute in
this area-39
Speciality Papers
Saturated asbestos paper is becoming too expensive compared to the
readily available plastic substitutes for cooling tower fill;-*° thus the
market should favor replacement of the asbestos fill presently in use, with
new substitute products. However, in specialty applications, such as cooling
for gaseous diffusions, asbestos fill is used rather than other materials
because of its superior heat and chemical resistant characteristics. The use
of asbestos-cement sheet as a cooling tower fill is rapidly decreasing due to
its potential for wear under extreme pH conditions creating a potential health
risk. Nonmetal fills are generally lighter than metal fills and, therefore,
have advantages in transport costs and handling ease. Asbestos paper is
considered the best fill material in terms of chemical and heat resistance,
but for most aplications, the extra chemical and heat resistance is not
critical. As indicated, plastic fills are becoming the most popular for
general applications.
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The advantages and disadvantages of DuPont's Nafion membrane product
substitute for electrolytic diaphragms have been covered under substitute
properties in this section. Even though there are many advantages, the
disadvantages in the lack of electrical efficiency as compared to asbestos
dictates further research and development before this product is a fully
acceptable substitute to asbestos. Clearly, this would affect the demand for
membrane cells vis-a-vis asbestos diaphragms, especially with rising energy
costs.
For substitutes to asbestos transmission paper, data are not available,
but indications are that substitute materials would probably not have the
requisite characteristics of asbestos and would be more costly.
Beverage Filters
Nonasbestos substitutes have already replaced asbestos filters in most
commercial applications. This trend will most likely continue until asbestos
is no longer used commercially for filtration. As indicated, the total
quantity of asbestos fiber currently used in making asbestos filters is
estimated to be only 30 metric tons annually-*-* 2 down significantly from the
late 1960s and early 1970s when over 907 metric tons of fiber was being
consumed. The future outlook points to the virtual disappearance of asbestos
filters. This is attributed to the concern of the beverage industry in
employing asbestos-containing products and the cost effectiveness of the
available substitutes.
Summary
Overall, the trend for asbestos paper products is in a state of flux.
Almost all categories show a stable or marginal decrease in the amount of
asbestos to be used. Only in a few instances, such as some specialty papers,
where the specific qualities of asbestos are absolutely essential, is there a
slight increase in asbestos consumption predicted. This "leveling off" of
asbestos use is generally attributed to the availability of acceptable, if not
closely identical alternatives. Changes in substitute quality and
availability will directly affect asbestos use in the paper products sector,
especially if the prices of substitute materials become more competitive with
asbestos. At the current time, prices of nonasbestos products are higher in
almost every paper product category.
CONCLUSION
Flooring Felt
In recent years, asbestos flooring felts have enjoyed an excellent growth
rate. During the period of 1971 to 1975, the growth was estimated at 14.8
percent annually, but this is projected to drop in the future, both because
asbestos has now replaced jute backings and substitute materials are providing
competition.
63
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A diversity of substitutes to asbestos flooring felt currently exist.
These substitutes are in the form of alternative floor materials and include
foam cushion backed flooring, backless sheet flooring, wood, and carpet.
"Place and Press" vinyl tile squares also enjoy high popularity with the
consumer. In addition, Pulpex flooring felt is currently being developed by
Lextar, which is working actively with major commercial asbestos felt
producers to reduce the cost of Pulpex to an equivalent asbestos cost.10
Roofing Felt
Since only organic felt roofs have been used for more than 20 years in
the United States, it is difficult to draw firm conclusions concerning the
long-term durability of the various roofing systems. Industry representatives
contacted differed in their opinions of the superiority of asbestos versus
fiberglass felts. One problem stems from the apparent variability in
fiberglass felts. Also, conversion to fiberglass felt mats requires
manufacturing experience and applicator training. Nevertheless, the major
manufacturer of fiberglass roofing reports significant gains for their product
in the total built-up roofing market. Due to rising asbestos costs, it is
expected that fiberglass felts will reduce the demand for asbestos roofing
felt. The newest system, the single-ply modified bitumen/plastic membrane, is
expected to further reduce the demand for asbestos felt, despite reported
performance and application problems, less fire resistance, and greater
sensitivity to weathering.3>19,21,106 problems with alternative materials
are being addressed by manufacturers; many difficulties will be minimized when
installers become more familiar with their use. In addition, the cost of
asbestos felt may increase relative to the other alternatives as it involves
the use of a greater amount of petroleum products.
Beater-Add Gaskets
Very recently, nonasbestos gaskets have been developed which are now in
the marketplace. Although alternatives are generally considerably more costly
than their asbestos gasket counterparts, and may not fill all of the product
niches that asbestos gaskets have created, this is likely to change as the
substitutes gain acceptance. For instance, it is reported that asbestos-free
materials are currently available that match existing material for cylinder
head and hard gasket applications.3? Companies originally dealing mainly
with asbestos products such as Rogers Company and Hollingsworth and Vose, now
produce adequate nonasbestos gasketing materials.
Pipeline Wrap
Although competitive products are occasionally used in the oil and gas
industry in place of asbestos pipeline wrap, this product is currently
preferred because of its cost and proven effectiveness. In addition, this
wrap is only needed with demand for new pipeline construction, so this
variable must be taken into account. The oil and gas industries currently
prefer the hot enamel system of pipeline wrap application which requires
either asbestos or fiberglass wrap. If the price of asbestos increases, this
64
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preference could well turn to fiberglass. In any case, the magnitude of any
drop in demand for asbestos pipeline wrap will not likely exceed several
percent annually, since most alternatives need additional product development
before they will be able to match the performance of asbestos pipeline wrap at
comparable costs.
Millboard
A number of substitutes for asbestos millboard are available which have
already led to a decline in demand for asbestos millboard and rollboard.
Moreover, substitutes are being developed that may be cheaper than some of
those now on the market. Many substitutes, composed of high temperature
alumina-silicate refractory materials, can withstand significantly higher
temperatures than asbestos and are stronger at higher temperatures as well.
Nonetheless, available substitutes are currently two to three times more
costly than conventional millboard. With the development of lower cost,
lower temperature substitutes, it is likely that, given the current level of
regulation and its effect on the costs of asbestos, these prices will approach
equality in the near future. In addition, the higher cost, higher temperature
substitutes will continue to fulfill needs that asbestos millboard cannot meet.
Commercial Papers
Historically, the growth rate for commercial asbestos paper has been very
slow, in fact, in 1975, the growth rate was estimated to be about zero,^ and
it is now slightly negative. The bulk of commercial paper produced is general
insulation paper. Industry concern about working with asbestos-containing
materials and the availability of some substitutes, although at greater
expense, has created the negative growth rate.
All of the primary manufacturers of asbestos commercial paper, except
Nicolet, Inc., have now diversified into substitute product lines for this
category. In the future, the market for nonasbestos commercial papers is
expected to improve, although it appears that the demand for such products is
not extensive. Substitute costs are very high at present, but should decline
as more research is performed and more substitute products infiltrate the
market. In addition, the performance of substitute products should improve as
increased knowledge is gained with use of these products.
Electrical Insulation
It appears that this category of asbestos paper products has several
viable substitute products available. The substitutes are described as
matching asbestos in the special qualities required in this application, but,
to date, have generally not matched asbestos in price. Higher prices of the
alternative products may become more competitive with consumer acceptance as
the length of time the products are on the market increases.
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Specialty Papers
This category includes transmission paper, electrolytic diaphragms,
filter paper, cooling tower fill, metal lining paper, and laminates. Many of
the products developed to replace asbestos specialty papers seem to be readily
available. The only exception is transmission paper where there are currently
no nonasbestos alternatives available, although research and development is
underway in this field. In electrolytic diaphragms, substitutes exist, but
are not equal to asbestos in properties and quality. Nonasbestos products
have already replaced asbestos in many filter papers and industrial laminates,
and comparably priced nonasbestos cooling tower fill and metal lining paper
are increasing in market share. There remain some deficiencies to correct;
research in such areas as disposal and handling of spent paper generated in
electrolytic chlorine production may also be desirable. Some asbestos
specialty papers are already being produced in lower volumes. With the many
alternative products available, this category appears to have the potential
for rapid reductions in asbestos consumption.
Beverage Filters
Asbestos beverage and pharmaceutical filters are not only produced and
consumed in very small amounts, but also will likely be totally replaced with
available substitutes in the not-too-distant future. However, as this is only
a small segment of the asbestos paper products industry, it is unlikely to
have any great effect. It has been concluded^, 96 that nonasbestos filter
sheets have reached the stage where they can be considered a full substitute
for asbestos filters. Further,'6 the comparative economics may favor the
nonasbestos filters since the filtering efficiency of the nonasbestos sheets
in some applications is considered equal to that of asbestos. However, for
haze removal from beverages, asbestos appears superior at present and some
beverage manufacturers still require this quality.°'
The major advantage of asbestos use in the past was its high positive
charge which attracts negatively charged ions. In Pharmaceuticals, bacteria
must be removed from products, and since most bacteria have negatively charged
ions, only asbestos filters were able to attract such ions.-'-O^ However,
newly developed products can receive such a charge and consequently act
similarly.
66
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REFERENCES
1. Clifton, R. A. Asbestos. 1980 Minerals Yearbook. U.S. Bureau of Mines,
Washington, B.C. 1981, p.4.
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6. Telecon. Schaum, M., Congoleum Ind., Cedarhurst, MD, with SRC, August
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11. Telecon. McLaughlin, C., Estimator, C and M Roofing, Somerville,
Massachusetts, (617) 623-3042, with D. Ramsay, GCA Corporation, August
20, 1979.
12. Telecon. Estimator, Matick Roofing Company, Chelsea, Massachusetts.
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67
-------
13. AIA comments to GCA's Draft Substitutes Performance Analysis Report,
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14. Syracuse Research Corporation. Communications to GCA/Technology
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15. Anonymous. Manual for Built-Up Roofs. Published by Johns-Manville
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16. Telecon. Frank LaMonica, Johns-Manville Corp., Denver, CO, with N.
Krusell, GCA/Technology Division, November 12, 1981. Notebook
#1-619-018-012, p. 7.
17. Telecon. Loretta Ferguson, Johns-Manville Corp., Denver, CO. (303)
979-1000, with Anne Duffy, GCA Corporation/Technology Division, April 13,
1981. Call #2.
18. Johns-Manville Asbestos Paper and Rollboard Specifications, including A.
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19. Belcher, Louis, GAP Corporation, letter to Joni Repasch, EPA OTS,
February 7, 1980.
20. Johns-Manville, Fact Sheet for Glas Ply Built-up Roofing Systems, 1979.
21. Telecon. Perkins, G., R-625 Products Marketing Manager, Owens-Corning
Company, Toledo, OH, with D. Ramsay, GCA Corporation, August 29, 1979.
22. Telecon. Company Representative, Water Guidance Systems (Susidiary of
Plymouth Rubber company), Brainford, Connecticut, (203) 481-4231, with D.
Ramsay, GCA Corporation, August 1979.
23. Telecon. Company Representative, Carlisle Tire and Rubber Division of
Carlisle Corp., PA, (717) 249-1000, with D. Ramsay, GCA Corporation,
August 1979.
24. Telecon. Company Representative, Gates Rubber Company, Denver, CO, (303)
744-1911, with D. Ramsay, GCA Corporation, August 1979.
25. Telecon. Company Representative, Bradco Supply Corp., Woburn,
Massachusetts, with N. Roy, GCA Corporation, August 23, 1979.
26. Telecon. Mr. Dennis Lupert, Owens-Corning Co., Roofing Division, Toledo,
OH. (419) 248-8775, with N. Krusell, GCA/Technology Division, November
17, 1981, Notebook //1-619-018-012, p. 15.
27 Lee, Robert F., Manager, Environmental Engineering, Rogers Corporation,
letter to Mr. Larry Longanecker, U.S. EPA, September 8, 1981.
68
-------
28. Telecon. Pat Thurber. Colonial Fiber Company, Division of Lydall Corp.,
Manchester, CT, (203) 646-1233, with Anne Duffy, CCA
Corporation/Technology Division, April 14, 1981. Call #9.
29. Telecon. Mrs. Loretta Ferguson. Johns-Manville Corp., Denver, CO, (303)
979-1000, with Anne Duffy, GCA Corporation/Technology Division. April
13, 1981, Call #2.
30. Telecon. Dot Hebert. Rogers Corp., Rogers, CT. (203) 774-9605, with
Anne Duffy, GCA Corporation/Technology Division. April 14, 1981. Call
#4.
31. Zeitz, John E., Division Chief Engineer for the Victor Products Division
of Dana Corporation, Lisle, IL, letter to Mr. Richard Guimond, U.S. EPA,
August 11, 1981.
32. Telecon. Sales Personnel, Carborundum Corporation, Niagara Falls, NY,
with D. Ramsay, GCA Corporation, August 1979.
33. Telecon, B. Reznic. Applications Engineer, Cotromics Corporation, 3379
Shore Parkway, Brooklyn, NY, (212) 646-7996, with M. Shah, GCA
Corporation, September 1979.
34. (PWC) Carborundum Corporation. Fiberfrax 110 Paper Product
Specifications. March 1979.
35. Telecon. Brunner, B., Customer Service Manager, Chicago Gasket Co.,
1277 West North Avenue, Chicago, IL, (312) 486-3060, with M. Shah, GCA
Corporation, September 1979.
36. Fry, Franklin, H., Vice President, Research and Development,
Hollingsworth and Vose Company, E. Walpole, MA, letter to Mr. Richard
Guimond, U.S. EPA, August 21, 1981.
37. Zeitz, John E. et al., Victor Products Division, Dana Corp., Lisle, IL.
Designing with the New Asbestos-Free Gasket Materials. SAE Technical
Paper Series 810366, 1981.
38. Production verified by Telecon. Company Representative, Celotex Corp.,
Tampa FL, (813) 871-4811, with Anne Duffy, GCA Corporation/Technology
Division, April 13, 1981. Call #3.
39. Miranker, Sam, letter to MaryAnne Chillingworth, GCA/Technology Division,
November 16, 1981, including product literature on Fibercoat by Textured
Products, Inc., 141 S. Central Ave., Hartsdale, NY.
40. Telecon. Weber, C., Market Manager, Industrial Products Division,
Johns-Manville Sales Corporation, Denver, CO, (303) 979-1000, with D.
Ramsay, GCA Corporation, August 29, 1979.
69
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41. Carton, R. J. Development Document for Effluent Limitations Guidelines
and New Source Performance Standards for the Building, Construction and
Paper Segment of the Asbestos Manufacturing Point Source Category. NTIS,
PB-238, 320. U.S. KPA, February 1974.
42. Gordon, W. A., and W. E. Riddle. Industry Profile and Background
Information on Asbestos Cement Products, Millboard and Lumber-Related
Products. U.S. Consumer Product Safety Commission CPSC-C-78-0091, Task
2, Subtask 2.02, February 1979.
43. Telecon. Pat Yoder. Nicolet, Inc., Norristown, PA, (215) 646-4000, with
Anne Duffy, GCA Corporation/Technology Division, April 14, 1981.
44. Telecon. Company Representative, Quin-T Corp., Tilton, NH, (603)
286-4362, with N. Krusell, GCA Corporation/Technology Division, April 23,
1981.
45. GAF no longer manufactures asbestos-containing products. Telecon.
Harvey Loud's office, GAF Corp., New York, NY, (212) 621-5000, with Anne
Duffy, GCA Corporation/Technology Division, April 13, 1981. Call #1.
46. Telecon. David Kendall, Research Triangle Institute, with P. LaShoto,
GCA/Technology Division, July 1979.
47. Anonymous. Fiberfrax Duraboard. Form C739-A, published by Carborundum
Corp., Niagara Falls, NY, 1979.
48. Telecon. Stein, C., Sales Representative, Pars Manufacturing Co.,
Ambler, PA, (215) 646-1300, with D. Ramsay, June 24, 1979.
49. Telecon. Kiser, W. F., Marketing Manager, Ceraform Products,
Johns-Manville Corp., Manville, NJ, (201) 725-5000, with D. Ramsay, GCA
Corporation, August 12, 1979.
50. Pye, A. M. A Review of Asbestos Substitute Materials in Industrial
Applications. Journal of Hazardous Materials (Netherlands) 3:137-138.
51. Telecon. Peter Heckman, Nicolet Co., Ambler, PA, (215) 646-4000, with S.
Bianchetti, GCA Corporation/Technology Division, June 27,.1980. Call #9.
52. Telecon. Neil Newell, Pyrotex, Carlisle, PA, (717) 249-2075, with S.
Bianchetti, GCA Corporation/Technology Division, June 27, 1980. Call #10.
53. Janos Industrial Insulation Corp. NU-Board 1800. Product literature.
54. Zeitz, John E. Division Chief Engineer, Victor Products Division of Dana
Corp., Lisle, IL, letter to Mr. Larry Dorsey, U.S. EPA, October 21, 1981,
including 12 attached exhibits.
70
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55. Telecon. Moganson, G., Customer Services, Insulation Division,
Carborundum Corp., Niagara Falls, NY, (716) 278-6389, with D. Ramsay, GCA
Corporation, August 1979.
56. Anonymous. Fiberfrax Ceramic Fiber Insulation. Form C544-5/78,
published by Carborundum"Corp., Niagara Falls, NY, 1978.
57. Telecon. Fenner, E., Director, Environmental Services, Johns-Manville
Corporation, Denver, CO, (303) 979-1000, with D. Ramsay, GCA Corporation,
July 26, 1979.
58. Telecon. Skold, J., Hunters Corporation, Fort Meyers, FL, with SRC,
August 1979.
59. Deutsch, Z. C., C. C. Brumbaugh, and F. H. Rockwell. Alkali and
Chlorine. Kirk-Othmer Encycl. Chem. Tech. (2nd ed.), 1^:681-699, 1963.
60. Dahl, S. A. Chlor-Alkali Cell Features, New Ion Exchange Membrane.
Chemical Engineering. August 18, 1975, p. 60-61.
61. Telecon. Cannady, D., Westinghouse Corp., Hampton, SC, with SRC, August
1979.
62. Cannady, D. Decorative Laminates. Modern Plastics Encylopedia, 77-78;
pp. 124-125. Published in conjunction with Modern Plastics, 54(10A),
McGraw-Hill Publication. October 1977.
63. Lewis, B. G. Asbestos in Cooling Tower Waters. Argonne National
Laboratory, Argonne, IL, NTIS No. ANL/ES-63, December 1977.
64. Clifton, R. A. Asbestos. Preprint from Bulletin 667, Mineral Facts and
Problems. 1975 ed. U.S. Department of Interior, Bureau of Mines, 1975;
and Personal Communication with SRC, 1979.
65. Telecon. Reis, J. F., Johns-Manville Corp., Denver, CO with RTI
(Research Triangle Institute), 1979.
66. Telecon. Lai, M., Hooker Chemical Company, Niagara Falls, NY, with SRC,
August 1979.
67. Anonymous. Asbestos Paper and Rollboard. Technical data sheet published
by Johns-Manville Corp., Denver CO, 1978.
68. Telecon. Company Representative, Johns-Manville, with Lester Y. Pilcher,
GCA Corporation, March 1980.
69. Telecon. Matt Smith, Munters Corp., Florida, (813) 321-6500, with Anne
Duffy, GCA Corporation, GCA/Technology Division, April 17, 1981, Call #26.
71
-------
70. Telecon. Mr. Cannady. Westinghouse—Decorative Micarty Division, (803)
943-2311, with Anne Duffy, GCA Corporation, GCA/Technology Division,
April 17, 1981, Call #31.
71. Telecon. Fenner, E. M., Johns-Manville Corp., Denver, CO, with SRC, July
1979.
72. Bureau of the Census, U.S. Department of Commerce, Industry Division.
Inorganic Chemicals. Current Industrial Reports, Publication
M28A(77)-4. Washington, D.C., April 1977.
73. Tresken, D. J. Mercury Consumption. Chemicals Economics Handbook.
Stanford Research Institute, Menlo Park, CA 1976.
74. Hausmann, E. Amelioration of Asbestos-Based Diaphragms and the
Possibility of Their Replacement with Semi-Permeable Membranes.
Commission of the European Communities, Luxembourg. October 3, 1978.
75. Anonymous. New Membranes Cut Chlor-Alkali Costs. Chemical Week. p. 33,
36, March 24, 1976.
76. Modi, David T. E. I. DuPont DeNemours and Company, letter to Joni T.
Respach, EPA. December 13, 1979.
77. Telecon. Cavicchio, E. , GAF Corp., Erie, PA, with SRC, August 1979.
78. Neisel, R. H., and H. F. Remde. Insulation-Thermal. Kirk-Othmer Encycl.
Chem. Tech., (2nd ed.) 11^832-833, 1966.
79. Anonymous. World Wide Directory of Products and Operations 1979.
Published by Johns-Manville Corp., 1979.
80. Telecon. Reis, J. F., Johns-Manville Corp., Denver, CO, with SRC, 1979.
81. Cotromics Corporation, Ceramic Paper Data Sheet, undated.
82. Johns-Manville product literature. Refrasil Fiber Papers—Cerafiber® and
Cerawool®. Ken-Caryl Ranch. Denver, CO. IND-242, 11-79.
83. Anonymous. Ceramic Paper. Engineering Data Sheet, published by
Cotromics Corp., Brooklyn, NY, August 1978.
84. Telecon. Hayman, J., Technical Service Representative, DuPont,
Wilmington, DE, with SRC, July 1979.
85. Telecon. Hughes, N., Quin-T Corp., Tilton, NH, with SRC, July 1979.
86. Telecon. Wilmore, R., National Electrical Manufacturing Association
(NEMA), Washington, D.C., with SRC, August 1979.
72
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87. Lair, W. Industrial Laminates. Modern Plastics Encyclopedia 77-78, pp.
128-134, published in conjunction with Modern Plastics JK10A);
McGraw-Hill Publication, October 1977.
8H. Tclccon. Lair, W., NVF Corp., Yorklyn, DK, with SRC, August 1979.
89. Masonite Corp. Benelex 402 Physical Properties.
90. Wet Ground Mica Association, Inc. Wet Ground Mica—A Unique and
Versatile Pigment. Newtown, CT.
91. Carborundum Corporation. Fiberfrax Ceramic Fiber.
92. Anonymous. Nomex Aramid. Bulletin NX-7, published by DuPont,
Wilmington, DE. November 1977.
93. Anonymous. Nomex Aramid. Bulletin NX-5, published by DuPont,
Wilmington, DE. December 1976.
94. Telecon. Hardy, B., Technical Service Specialty Dept., DuPont,
Wilmington, DE, (302) 999-3622, with M. Shah, GCA Corporation, September
13, 1979.
95. Fiore, J. V., and R. A. Babineau. Filtration—An Old Process with a New
Look. Food Technology. 3_3_(4) :67-72, 1979.
96. Held, R. Nonasbestos Filter Sheets. The Brewers Digest. December 1978,
pp. 38-42.
97. Telecon. Varleriote, S., Cellulo Co., Fresno, CA, with SRC, July 1979.
98. Telecon. Company Representative. Alsop Engineering, Milldale, CT, (203)
628-9661, xtfith Anne Duffy, GCA Corporation, GCA/Technology Division,
April 17, 1981, Call #30.
99. Telecon. Don Wheaton, Cellulo Co., Fresno, CA, (209) 485-2692, with Anne
Duffy, GCA Corporation, GCA/Technology Division, April 17, 1981, Call #27.
100. Telecon. Mr. Hallet, Ertel Engineering, Kingston, NY, (212) 226-6023,
with Anne Duffy, GCA Corporation, GCA/Technology Division, April 17,
1981, Call #28.
101. Telecon. Held, R., Filter Products Co., Richmond, CA, with SRC, August
1979.
102. Telecon. Lavery, F., Sales Manager, Ertel Engineering Company, Kingston
NY, (212) 226-6023, with M. Shah, GCA Corporation, September 1979.
73
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103. Telecon. Gusmer, J., President, Cellulo Company, Waupaca, Wisconsin,
with M. Shah, CCA Corporation, (715) 258-552(>, September 1979.
104. Letter from J. Gusmer, Cellulo Company, to M. Shah, GCA Corporation/
Technology Division, September 10, 1979.
105. Telecon. Sales Representative, Evans Products Co., Forest Fiber Products
Group, Glass Fiber Division, Corvallis, Oregon, with R. Bell, GCA
Corporation/Technology Division, September 21, 1980.
106. Telecon. Noble, A., Assistant Sales Manager, Koppers Company, Eastern
Division, West Orange, NJ, (201) 736-9150, with D. Ramsay, GCA
Corporation, August 30, 1979.
107. Telecon. Salesman, Bradco Supply Corporation, Woburn, Massachusetts,
with D. Ramsay, GCA Corporation, August 17, 1979.
108. Carborundum Corporation. Fiberfrax Paper 110 Series Price Schedule. May
1979.
109. Telecon. Sales Secretary, DuPont, Wilmington, DE, (302) 744-2421, with
M. Shah, GCA Corporation, September 1979.
74
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SECTION 3
|
FRICTION MATERIALS
ASBESTOS PRODUCT
Special Qualities
All products containing friction materials rely on the coefficient of
friction between mating surfaces to transmit or stop motion. Brakes convert
kinetic energy into heat, absorb the heat, and gradually dissipate it into
the atmosphere. Brakes consist of two parts, the rotor which is connected to
the wheel, and the stator on which the friction material is mounted.* Clutches
transfer kinetic energy from a rotating crankshaft to the transmission and
wheels. Both brakes and clutches may operate wet or dry. In dry systems, the
heat is conducted to the air and surrounding structure while wet systems oper-
ate within oil or another fluid which absorbs the heat to maintain temperatures
below 200°C (392°?).^ The special qualities required by friction materials
include:
• Possession of the appropriate coefficient of friction for
the desired application
• Ability to withstand the high temperatures generated at
friction interfaces
• Dimensional stability
*This basic description of a brake applies to automotive disc brakes; other
friction products including drum brakes and clutches, cone brakes and
clutches, band brakes and clutches, centrifugal brakes and clutches, and
plate clutches, although composed of different parts, require the same
special qualities listed.
In dry brakes, the heat at the friction surface can be dissipated by convec-
tion and/or conduction and/or radiation. In high energy stops on automotive
disc brakes or in continual braking coming down mountain slopes, a major
amount of heat is lost by radiation from the exposed hot disc.1 Tempera-
tures at this time may reach 400°C. »
75
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• Strength
0 Durability
• Lack of abrasive characteristics which could lead to
scoring of mated surfaces.
In addition, most friction materials also require:1
• Low wear rate
• Lack of noise
o Lack of compressibility
• A very high coefficient of friction under cool, humid
conditions at low rubbing speeds
• Ability to be manufactured in high volumes with consistent
physical properties
• No "rust bonding"; i.e., the material will not become
bonded to metal disc or drum while in pressure contact,
especially under wet conditions.
Asbestos is used in friction materials because of the properties listed
in Table 11. The most important properties are thermal stability, reinforc-
ing abilities, relatively high friction, fiber flexibility, and relatively
low cost.
TABLE 11. UNIQUE PROPERTIES OF ASBESTOS APPLICABLE TO FRICTION MATERIALS3
Properties Comments
Fibrous form Flexibility contributes to forming characteristics.
Fibers interlace and interlock, enhancing strength.
Flexibility reduces wear at friction interfaces.
Fine fiber diameter Provides strong reinforcing characteristics because
of the large number of fibers per unit weight.
High tensile strength Provides strength and durability to friction
products.
Temperature resistance Chrysotile unaffected by T <200°C (400°F). Able to
withstand high temperatures generated at friction
interfaces, up to 400°C (750°F). The temperature
of maximum ignition loss is 1000°C (1800°F).
Cost Provides low cost/performance or cost/physical
property ratio.
76
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Product Composition
Friction materials for automotive brakes and clutches are complex com-
posites of three general types of ingredients:
• reinforcing fibers,
• property modifiers, and
• organic binders.
Historically, asbestos fibers have been the major constituent of nearly all
organic friction materials, so chosen because of their thermal stability, fric-
tion level, reinforcing properties, availability and relatively low cost.
Small quantities of other fiber reinforcement may also be used. Because asbes-
tos alone does not provide all of the properties required for friction mate-
rials, property modifiers are added to provide various degrees of friction,
wear, fade, recovery, noise, and rotor compatibility. A resin binder is used
to hold materials together and contributes to the friction characteristics
of the mixture. Table 12 lists common ingredients found in several patent
formulae.* Following is a more detailed description of the raw materials used
in organic friction material.
Binders—
In wet mix processing, a viscous material (usually a creosol) is used.
In dry-mix processing, a powdered material (usually a novolac) is used.
Phenolic and cresylic reins (both synthetic) are the most commonly used binders
and are normally modified with drying oils, rubber, cardanol, or epoxy.
Fibrous Reinforcements—
The asbestos normally used in friction material is chrysotile. The size
distribution of asbestos fiber consumed by the friction materials industry in
1980 consisted of chrysotile grades 3 through 7 (predominantly grades 7 and 5).6
A total of 43,700 metric tons was consumed. Long-fiber asbestos (grades 3, 4,
and 5) is used in dry-mix processing and short-fiber asbestos (grades 6 and 7)
is used for wet-mix processing. The longer fibers permit the bending of linings
from flat to curved segments. Clutch materials contain additional continuous-
strand reinforcements including cotton, asbestos, yarn, brass wire, and copper
wire. .
Property Modifiers—
Property modifiers can be classed as nonabrasive and abrasive. Table 13
lists property modifiers and their functions in organic friction materials.
*The formulations shown in Table 12 contain little or no resin and therefore
could not be made commercially through the dry mold process discussed, but
would instead be made by extrusion or in some cases by the sheeter process.1
These formulations are not for organic linings but rather for more heavy-
.duty applications requiring less resin.
77
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TABLE 12. TYPICAL INGREDIENTS USED FOR SOME FRICTION MATERIALS
(IN WEIGHT %)">a
Cupol ymers
A
B
C
I)
E
F
r,
H
T
.1
K
L
M
N
0
P
Q
R
22
11
17
15
15
15
15
15
15
15
13
13
15
15
15
17
17
17
c
Asbestos
49
63
54
58
58
79
69
69
79
69
55
64
15
69
69
49
65
69
Sul fur
2
1
2
2
1
1
1
1
]
1
1
1
ZinC; Cardolit/
oxide
4
2
3
3
3
3
3
5
3
3
2
3
6
3
4
4
4
4
10
10
9
10
10
30
10
10
Resin ll;irite Rotcenstone .,....,
additives
12 12
12 12
12 12 I6
12 12
13 12
2
2
2 10f
2 178
6 lh
5 401
2 10f
2
4k
As these ingredients consist of only small amounts of resin for the formulas given, the
friction materials arising from these formulas are assumed to be for stiffer, heavy-duty
applications which require less resin content than organic linings.
Acrylonitrile-butadiene copolymer
Grade 5K chrysotile.
Friction dust made from cashew-nut shell oil (3M tradename).
g
Abundum (600 x) - aluminum oxide.
Unidentified friction particle.
8Zinc dust.
F"araformaldehyde (curing agent).
Steel wool.
Iron oxide.
^
Orion fiber.
78
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TABLE 13. PROPERTY MODIFIERS IN FRICTION MATERIALS
5,7-9
Modifier
Function
Nonabrasivi:
Ciirdo I i Lc (cashew friction dust)
Ground rubber
Carbon bl ack
Petroleum coke flour
Graphite
l!i I sonite
Abrasive
Brass chips
Copper powder
Rottenstone (decomposed siliceous limestone)
Q ua r t z
Wol last-unite
Zinc
A Iuminum
Xinc i:liips
Limes Lone
Clays
l-'inely divided stl icas
liar ill.'
Noise, wear and abrasion control
A I uniina
S i I icon carbi.dt!
Kyaivi Lc
Mn 1 y bdc'ii itc
Ca 1 c i uin I" 1 nor ido
Load and compounds
AnLimony cumpounds
Calcium compounds
Barium hydroxide
I'oLassluni ilichromato
Matin's i urn carbonate
I run iix ido
CryoI i Lo
Nickel
Sulfur
/!OU mesh
Scavengers, breakup surface films
Recovery of normal performance after fade
Improve wear resistance
Increase friction level
Lubricant
Use not defined
79
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Uses and Applications
The primary uses for friction materials are brakes for light- and heavy-
duty vehicles, aircraft, railcars, and various types of heavy equipment. Clutch
facings are another important friction material product. Minor uses include
braking mechanisms for bicycles, presses, hoists, lift trucks, mining and drill-
ing equipment, chain saws, tape recorders, spinning and knitting equipment,
typewriters, snowblowers, and washing machines. In addition, many business
machines require clutch mechanisms. These applications are very diverse and
demanding. Out of hundreds of formulations either tested or developed to meet
such standards in the past several years, only a very few nonasbestos composi-
tions have proven suitable.1
The primary uses for asbestos-containing friction materials in automotive
and railcar applications are listed in Table 14. Additional applications in-
clude the use of asbestos friction products in agriculture, construction, mining,
logging, marine, oil well drilling equipment, and industrial work.1
Product Manufacturing Summary
Manufacturing Process—
Production methods and raw materials used in the manufacture of friction
materials vary, depending on the intended application of the final product.
Organic linings, which must bend, require high resin contents and long
fibers. Stiffer, heavy-duty materials with less resin require molding for
shape and clutch materials require special fiber-forming methods. Major manu-
facturing methods are described below.
Linings—Most linings are produced from resin wet-mix by extrusion or in
rolling processes.* Asbestos and various property modifiers are mixed with
liquid resin at 50°C (120°F), then binder solvent is added to yield a putty-
like mass with good wet strength. In the extrusion process, the mix is heated
to 90°C (195°F) and extruded as a flat, pliable sheet which is dried for 2
hours at 80°C (175°F). In the rolling process, the partially dried mix is fed
between two rolls that align the fibers into flat, pliable "green lining."
Linings are then cut to length, formed at 150°C (300°F), and molded for 4 to
8 hours at 180° to 250°C (360° to 480°F). The final product is ground to pro-
duce finished brake linings.
Linings for heavy-duty use are produced by a dry-mix process. Asbestos,
modifiers, and resin are mixed and formed into 60 x 90 cm (24 x 35 inches)
briquets that are pressed for 3 to 10 minutes at 140° to 160°C (340° to 375°F),
and cured in molds for 4 to 8 hours at 220° to 280°C (425° to 540°F). The
brake linings are finished after grinding.
*Although most linings are made with these processes, other processes used
should be noted. These include the rotting, sheeter, and millboard processes.
Linings made by last two processes have characteristics that are hard to find
in materials made by the other three processes.1
80
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TABLE 14. USES OF ASBESTOS-CONTAINING FRICTION MATERIALS
Product
Characteristics
Applications
oo
Drum brake linings
Non-servo linings
Class A disc pads
Class B disc pads
Truck segments
Class C brake blocks
Clutch friction materials
High and stable friction at temperatures
up to 250°C (480°F). Tensile strength
of 4000 to 5000 psi.
Stable friction, wear resistant, tensile
strength of 4000 to 5000 psi.
Nonabrasive friction and wear, quiet,
wear resistant up to 300°C (570°F), low
coefficient of friction, tensile strength
of 4000 to 5000 psi, rotor compatibility.
Higher friction, wear resistant up to
350°C (660°F) but less wear resistant at
lower temperatures, less quiet, tensile
strength of 4000 to 5000 psi.
Stable friction, wear resistant, tensile
strength of 4000 to 5000 psi.
High friction minimal fade, wear resis-
tance to 400°C (750°F) at the expense of
other brake characteristics.
Stable friction, good wear up to 250°C
(480°F), quiet, very high tensile
strength of 10,000 psi.
Automobiles and light trucks.
Rear wheel drum brakes of small
front-wheel drive vehicles, K-car,
Citation, etc.
Large and medium-sized
United States-made automobiles.
European-made automobiles and
light trucks.
Front drum brakes of medium-duty
trucks (10,000-15,000 Ibs).
Heavy-duty trucks.
Automobiles.
Table compiled from Reference 2 and Reference 7.
Listing goes from light-duty applications to heavy duty.
r*
"It should be noted that this category includes both "primary" and "secondary" drum brake linings in
servo drum brakes. The primary essentially activates the secondary and both linings are exposed to
the same environment; i.e., temperature, and since they are in the same brake they fit the same
applications. This servo brake is declining in usage.1
-------
Disc pads—A dry-mix is prepared as for hcavy-duLy linings. The mix is
formed into briquets at room temperature and 27.6 to 41.4 MPa (4000 to 6000
psi). The briquets are pressed at 160° to 180°C (320° to 355°F) and 27.6 to
55.2 MPa (4000 to 8000 psi) for 5 to 15 minutes and are then cured at 220° to
300°C (430° to 570°F) for 4 to 8 hours. Grinding produces the final product.
Blocks—Asbestos reinforced brake blocks are prepared by a dry-mix process.
Briquets are formed at 10.3 to 17.2 MPa (1500 to 2500 psi) and heated to 90°C
(195°F) for 15 to 30 minutes to reduce blistering during hot processing. Blocks
are formed at 130° to 150°C (265° to 300°F) and 13.5 to 20.7 MPa (2000 to 3000
psi) for 10 to 30 minutes. The blocks are then cut and ground to shape. Final
curing takes place in confined or unconfined form. After grinding, drilling,
and chamferring, the block is finished.
Clutch materials—A primary concern in one manufacturing method of clutch
materials is the placement of the wire reinforcement within the matrix. A dry-
mix is used in molding without wire or molding around wire preforms. Another
method is to prepare a wet mix and run a wire through the viscous material.
The surface is ground to final shape after pressing and curing.
Woven bands—Woven bands for heavy-duty uses are produced by a process
that begins with asbestos cord (which may be reinforced with wire) being passed
through a wet-mix to pick up resin and modifiers. The saturated cord is then
woven into tapes that pass through heated rolls to partially cure the resin.
The material can be post-cured at 160°C (320°F) to remain as a flexible roll
lining or post-cured at 280° to 230°C (355° to 445°F) to form rigid segments.
Such materials are found in large band brakes used to control large machinery.
Name and Number of Manufacturers—
There are 30 major manufacturers of asbestos-bearing friction materials,
listed in Table 15. Both large diversified companies such as Raybestos-Manhattan
and small single product companies are included in this list. The first few
companies listed in this table accounted for a majority of the total estimated
sales of asbestos-containing friction materials in 1975, a pattern consistent
with the industry's historical trend. From 1954 to 1967, the eight larger
companies together accounted for 86 to 91 percent of the industry's value of
shipments.
Production Volumes—
Table 16 gives the consumption of asbestos in friction products for the
years 1969 to 1980. Figures for production volumes were not available, but
a breakdown of the value of asbestos-bearing friction materials projected to
1981 from 1972 values given by Meylan is provided in Table 17.
82
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TABLE 15. U.S. MANUFACTURERS OF ASBESTOS-BEARING FRICTION MATERIALS10"36
OJ
Plant
Company location(s)
••.•vh-.-'srob-:; '.nhr.r.tan, Inc.'* Stratford, CI
RM Friction Materials Co. Mannheim, PA
Crawfordsville, IX
Marshville, NC
N. Charleston, SC
t
Bendix Corporation* * Troy, NY
Automotive GRP Cleveland, TN
South Bend, IX
Abex Corporation''1 Cleveland, OH
Friction Products Group Troy, MI
Winchester, VA
General Motors1'' Dayton, OH
Delco-Moraine Dtv., Inland Div.
H. K. Porter Company15 Huntington, IN
Thermoid Div.
Chrysler Corporation12 Tenton, MI
Cycleweld Div.
Borg-Warner Corporation1* Bellwood, IL
Nuturn Company" Nashville, TN
(formerly World Bestos Co.) Paulding, OH
Maremont Corp. , Grizzly
Products, Div.
National Friction Products Logansport , IN
Corporation1 9
Auto Specialties Manufacturing St. Joseph, MI
Company1 9
Standee Industries'" Houston, TX
Friction Products Company21 Medina, OH
Royal Industrial Brake Products Danville. KY
2 2
Inc.
Reddaway Manufacturing Company'1 Newark, NJ
Molded Industrial Friction Prattville, AL
Corporation2" -
Wheeling Brake Block Manu- Wheeling, WV
facturing Co.25 Bridgeport, OH
F r • 2 6
~ — - ~=^,
Products
Brakes Clutches
Automobile Heavy • In- Ve- In- Estimated
and duty Rail- dus- hi- dus- 1978 sales*
lighc truck truck car trial cle trial Comments (S million)
Drum, disc Disc •• > 165-0
segment ,
block
Drum, disc Block » > Brakes - machine tools, off-highway 9--V.5
equipment
Drum, disc Block »"' 66.6
Drum, disc ' 16.2
Drum, disc »•' 26. 5
Drum, disc
Drum, disc /
Block ' 21.5
*f -' -' Off-road vehicles, cranes, shovels, 12.0
travel trailers, mobile homes,
plant machinery, appliances.
Drum, disc ' „•' / Off-road vehicles, agricultural 0.66
equipment .
-' *' Off-road equipment, winches, cranes, 8.7
drilling rigs.
Block / ,' ,-' 4.0
Drum, disc Assembly of parts from Canadian 16.0
manufacturers .
•' •' 3.0
Block -Tractors and trailers. 3.6
Block 40
• ^ Disc and plate brakes, railcar and
diesel engine brakes, tramways,
off-road vehicles.
(continued)
-------
TABLE 15 (continued)
Company
Brassbestos Manufacturing
Corporation' '
Auto Friction Corporation" ' *a
Gatke Corporation' '
Lasco Brake Products Company"
MGM Brakes, Incorporated5'
Carlisle Corporation"
Thiokol Chemical Corporation'3
Eaton Corporation11*
Scan-Pac Manufacturing
Company"
OO Guardian Corporation, Inc. Jt
•P- ,,
H. Krasne Mfg. Co.
U.S. Automotive Manufacturing56
Products
Brakes
Automobile Heavy In-
Plant and duty Rail- dus-
location(s) light truck truck car trial
Patterson, NJ Drum, disc
Lawrence, MA Drum Drum
Warsaw, IN
Oakland, CA Drum, disc Block
Cloverdale, CA Block
Ridgeway, PA Block
Trencon, NJ Drum, disc
Kenosha, WI Block,
disc
Menomonee Falls, WI
Brighton, MA Disc
Los Angeles, CA Disc
Tappahannock, VA Disc
Tappahannock , VA Disc
Clutches
Ve- In-
hi- dus-
cle trial Comments
Rebuilt
Custom manufacturing
Off-road vehicles, buses, rail-
cars, mining equipment, towing
vehicles.
Buses, off-road vehicles.
Rebuilt for replacement, as well as
original equipment
Off-road nonautomotive brake
linings
Also, brake noise inhibitors
Eszi^atec
197S sales'
(s 3i::icr...
i.j
26.5
•2.0
3.6
.;
IS . 2
5.7
-
:.6
Vr.knevr.
I'r.kncwr.
1'r.knot.T.
I'r.icr.ovr.
This is also called P. T. Brake Lining Company, Inc.
-------
37
1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980
TABLE 16. ASBESTOS CONSUMPTION BY THE FRICTION MATERIALS INDUSTRY
(THOUSAND METRIC TONS)
64
60
62
66
72
73
60
58
83
82
61 43.7
TABLE 17. VALUE OF ASBESTOS FRICTION MATERIAL SHIPMENTS
(IN MILLIONS OF 1981 DOLLARS)3
Final product
Total product
shipments, including
interplant transfers
1981
1972
Percentage
of
total
Brake linings
Woven, containing asbestos 27.8
yarn, tape or cloth
Molded, including all 308.4
nonwoven types
Disc brake pads 38.8
Clutch facings
Woven, containing asbestos 54.2
yarn, tape or cloth
Molded, including all 132.2
nonwoven types
Other 9.8
Total asbestos friction material 571.2
10.2
113.1
14.2
19.9
48.5
3.6
209.5
4.9
54.0
6.8
9.5
23.1
1.7
100.0
Projected by Meylan et al. 1972 data adjusted to 1981,10 p. 61,
using September 1981 Engineering and Mining Journal cost index factors.
The 1972 breakdown was the best available data, but it should be noted
that corresponding percentages of total, for example with disc brakes,
may have changed more than this table shows.
85
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SUBSTITUTE PRODUCTS
Methodology
Search Strategy—
Twenty of the largest United States asbestos product manufacturers, as
listed in Meylan,10 were investigated to determine which friction materials
are being produced. These manufacturers were questioned regarding both asbes-
tos and substitute materials. Relevant trade associations were also contacted.
Several sources in the literature were recommended by the above contacts. The
section in the Encyclopedia of Chemical Technology entitled Brake Linings and
Clutch Facings7 was very useful in the writing of this section.
Summary of Contacts—
The following individuals and companies provided useful information con-
cerning friction materials.
Robert A. Clifton
U.S. Bureau of Mines
2401 E St., NW
Washington, DC 20241
Robert Curran, Chief Engineer
Spring Division
Borg-Warner Corporation
700 South 25th Ave.
Bellwood, IL 60104
George Bason
Director of Advertising and
Public Relations
Abex Corporation
530 Fifth Avenue
New York, NH 10036
Jack Reynolds
Johns-Manville Corp.
Ken-Caryl Ranch
Denver, CO 80217
Leon Kopyt
Mass Transit Systems Corp.
Suite 1428
Suburban Station Building
Philadelphia, PA 19103
Walter Nichols
Sales Representative
Midland-Ross Corporation
55 Public Square
Cleveland, OH 44113
Eugene Connor, National Sales Manager
Johns-Manville Corp.
Ken-Caryl Ranch
Denver, CO 80217
Joe Minsky
P.T. Brake Lining Co., Inc.
18 Shepard St.
Lawrence, MA 01842
Mr. Baltz, President
Baltz Co., Inc.
28 Robinson Rd.
Lexington, MA 02173
Raybestos-Manhattan, Inc.
100 Oakview Drive
Trumbull, CN 06611
Kevin Peppard
Asst. Dir. of Business Planning
Automotive Group
Bendix Corporation
40 North Bendix Dr.
P.O. Box 4001
South Bend, IN 46634
Mr. Anderson, Sales Mgr.
Royal Industries, Inc.
Brake Products Division
Stewarts Lane
Danville, KY 40422
86
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Edward W. Drislane
Executive Director
Friction Materials
Standard Institute
East 210, Route 4
Paramus, NH 07652
Michael Jacko
Bendix Materials Center
Bendix Center
Southfield, MI 48037
Mr. Gorney, Mr. Alek
Griffin Wheel Co. (Division
of Amsted Industries, Inc.)
200 W. Monroe St.
Chicago, IL 60606
Terry Blaine
Spring Division
Borg-Warner Corporation
700 South 25th Ave.
Bellwood, IL 60104
Paul Biondo
Auto Friction Corp.
652 Andover St.
Lawrence, MA 01842
Robert Randolf
Gatke Corp.
E. Winona Ave.
Warwaw, IN 46580
Lasco Brake Products Corp., LTD
26th & Magnolia Sts.
Oakland, CA 94607
Mr. Apollogene, Sales Representative
MGM Brakes
21800 Greenfield St.
Detroit, MI 48236
Carlisle Corporation
511 Watnut St.
Cincinnati, OH 45202
Thiokal Corporation/Chemical Div.
P.O. Box 1296
Trenton, NJ 08607 .
Jack Payton, Shop Superintendent
Friction Products Co.
922 Lake Rd.
Medina, OH 44256
Standee Industries, Inc.
P.O. Box 87
Houston, TX 77001
Bill Shine, Sales Administrator
Auto Specialties Mfg. Co.
P.O. Box 8
St. Joseph, MI 49085
Donna Craven, Customer Service
Scandura, Inc.
P.O. Box 949
1801 N. Tryon St.
Charlotte, NC 28231
Brassbestos Mfg. Corp.
45 E. 5th St.
Paterson, NJ 07524
Earl Fygert
Sales Manager
National Friction Products Corp.
1441 Holland St.
Logansport, IN 46947
Mr. Sleeth
H.K. Porter Co., Inc.
Thermold Division
315 Porter Bldg.
Pittsburgh, PA 15219
Mr. Montgomery, General Manager
Stanley Belting Co. (Distributors
for Reddaway Mfg. Co.)
28 Euclid Ave.
Neward, NJ 07105
Wheeling Brake Block Mfg. Co.
3602 Jacob St.
Wheeling, WV 26003
Reginald Kelley, General Sales Manager
Force Control Industries, Inc.
3656 Dixie Highway
Hamilton, OH 45014
87
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Roy Huckabee, Sales Representative
Nuturn Co. (formerly World
Bestos Co.)
1112 S. 25th St.
New Castle, IN 47362
Fiber Substitutes
Most companies have pursued the development of both fiber and product
substitutes to ensure asbestos-free products at the earliest possible date.
Both naturally occurring and synthetic materials have been evaluated as sub-
stitutes to asbestos in friction products. Evaluations are made on the basis
of friction stability, wear, effect on opposing surfaces and noise. In addi-
tion, some manufacturers are currently placing equal emphasis on the evalua-
tion of safe materials to eliminate potential health hazards. In many cases,
direct substitution of the alternatives mentioned here has resulted in poor
friction levels, friction instability, roughness, structural failure, in-
creased noise, mating surface deterioration and/or front to rear brake im-
balance, such that complete reformulation is necessary as a further course of
action.38 Processing nonasbestos fibers is difficult as most fibers are very
brittle, have little or no surface adsorptivity, and are difficult to handle.
Often the nonasbestos product is noisy in use. Whereas asbestos fiber bundles
open during mixing to entrap the friction modifiers and resin, giving a con-
sistent mix, nonasbestos fibers often spring back and their low tack leads
to weak structures. Asbestos has a high, stable friction level, good adsorp-
tivity for strength and wear resistance and does not contribute significantly
to noise; substitute fibers generally show greater frictional instability,
little or no surface adsorptivity, and/or a significant contribution both to
the noise factor and to mating-surface degradation.38
Substituting a class A organic disc pad for a semimetallic, for example,
results in greater wear (especially in compact cars with solid rotors). Many
factors such as these influence the special quality attributes of asbestos
versus substitute materials in this area.
Special Qualities and Product Composition—
These are given for the following materials, which have been proposed as
substitutes for asbestos in various friction materials. Some have been suc-
cessful in replacing organic friction materials for some applications. Table
18 summarizes the advantages and potential problems with these materials as
compared to asbestos.
Glass fiber—The overall strength of glass fiber is lower than that of
asbestos but strong enough for friction material applications. Although
currently produced, problems with glass fiber use include melting at the
temperatures reached at braking interfaces even in depths below the operating
surface, causing fade. Glass also looses its fibrous form in high shear
mixing, has low wear resistance, and wears aggressively.
Steel wool1°—Compared to asbestos, the overall strength of steel is
lower and its cost is higher. The material hardness of steel wool can result
in damage to the brake rotors, and special formulating techniques are required
to control the friction and adhesive wear properties. Class B organic disc
pads usually are more aggressive to the rotor and noisier than semimetallic disc
pads.9
88
-------
TABLE 18. REINFORCING FIBERS AND OTHER MATERIALS FOR FRICTION MATERIALS'
Fiber
Advantages
Potential problems
Asbestos High strength and modulus
Thermal stability
Infusible
Good wear
Also acts as filler
Aramid (Kevlar®) High strength and modulus
Thermal stability
Nonaggressive wear
characteristics
Steel Fiber
Adequate strength and modulus
Thermal stability
Glass
Adequate strength and modulus
Controllable fiber dimensions
Cermets-Sintered High thermal stability
Materials
Silicon Nitride
Noroloid Fibers
Carbon Fibers
Mineral Wool
Semimetallic
Materials
Vermiculite
Long service life, high
,thermal conductivity
Highly insulating, flame-
retardant, nonmelting
High strength, very high
modulus
Infusible
High thermal stability
Low density
Inexpensive
Thermal stability
Excellent wear resistance
High temperature strength
Linked to health problems
due to effects of some
fiber sizes
Needs special attention in
mixing
Noisy
Corrosion
Low cold friction
Costly
High density
Melts at very high tempera-
tures causing fade
Loses fiber form in high
shear mixing
Molding spring back
Low wear resistance
Aggressive wear
characteristics
High cost, insufficient wear
resistance, high thermal
conductivity
Exp en s iv e, h eavy
Loses fiber form in mixing
Costly
Low temperature and impact
strengths
Low strength, brittle
Expensive
Halvar Y. Loken, Industrial Fibers Div., E.I. duPont de Nemours & Co., Inc.,
Wilmington, DE,39 in combination with GCA literature reviews.
89
-------
Mineral wool—The overall strength of mineral wool is very low and
brittle to the extent of limiting mixing processes.
Potassium titanate fibers—The National Aeronautical and Space Adminis-
tration (NASA) has investigated new friction materials and their applica-
tions outside the space program. As part of this effort an improved friction
material was developed that utilized potassium titanate fibers with the DuPont
tradename FYBEX for lightweight cars and trucks. However, unfavorable toxi-
cological effects and other market considerations caused DuPont to withdraw
FYBEX from the market.
Silicon nitride** —This material was used for the brake pads in proto-
types of the Concorde. It has a longer service life than asbestos and higher
thermal conductivity (desirable in this application) but is more expensive
and heavier than the carbon composites eventually adopted.
IL J_
Noroloid fibers —Noroloid fibers were invented by the Carborundum
Company in the late 1960s. Made from novolak (phenol-formaldehyde) resin,
the fibers are compatible with many resin and rubber matrices. The manufac-
turer claims the highly insulating, flame-retardant and nonmelting fibers
are finding increased acceptance as a replacement for asbestos in, among
other applications, friction materials.
Carbon fiber7—The main properties of carbon fibers are good, espe-
cially for carbon-composite friction materials and rotors ("carbon brakes");
in other applications, however, they remain somewhat inferior to asbestos.9
A major consideration is cost, which is a great deal higher than for asbestos.
It is more efficient than asbestos under high service temperature conditions,
but heat flow is uneven and the tensile and impact strengths are relatively
low. It has high thermal stability and low density, making it especially
attractive for aircraft brakes. Abex Corporation of New York, NY took out a
patent for a nearly pure carbon article for replacement of brakes or clutch
discs in 1971. Abex makes tiger composition brake shoes containing fiber,
rubber, resinous material and fillers.
Vermiculite—A British patent was recently issued for a vermiculite-
based brake lining. The composition of this product is given in Table 19.
Vermiculite is ground and sieved to a grade of fineness, or aspired to a higher
grade of fineness, and.then cold treated with the ingredients found in this
table. Although not produced in volume, it serves as an example of continuing
research and development activity aimed at replacing asbestos in brake linings.
TABLE 19. BRAKE LINING TREATMENT FORMULATION
FOR VERMICULITE-BASED BRAKES'*2
Material % Composition
4% solution of rubber 40
Calcium carbonate 15
Barium sulphate 15
Synthetic rubbers 20
Iron oxide, zinc oxide,
chromium oxide 10
90
-------
Delaminated vermiculite is used in friction materials commercially avail-
able throughout Europe. They maintain strength at high temperatures, are com-
patible with phenolic resins, require little attention in manufacturing methods,
and may be used with asbestos to help reduce asbestos content.1*0
Aramid fibers—Kevlar® aramid fiber is made of an infusible aromatic poly-
amide polymer. Inert fillers are then selected on the basis of thermal and
wear characteristics, with less concern about other properties due to Kevlar's
efficient strengthening. One brake mix tested consisted of: 50 percent wol-
lastonite, 20 percent barium sulfate, 15 percent dry phenolic resin, 15 per-
cent cashew friction particles, strengthened with different forms of Kevlar
at the 5 percent level. Kevlar can be bought as cut fiber, which can be pro-
cessed in a mixer to any length. Kevlar can also come as a continuous fila-
ment whch gives the highest strength conversion, or as a pulp which is more
fibrillated and shorter than cut fiber and can be readily processed into fric-
tion paper.39
Aramid fibers are being researched for use in high performance dry clutch
facings, automatic transmissions and asbestos-free brakes. Kevlar, for exam-
ple, has high tensile strength and is reported to be five times stronger than
steel on a weight basis.39 Composites have good resistance to external abra-
sion, high frictional stability, excellent durability and much better high
temperature properties than common organic fibers. They are used in disc
brake pads with wear levels between asbestos and semimetallics, and are now
in experimental use in drum brake linings and wet friction papers. They do
not score mating surfaces and can presently be found in manual transmissions
for Mercedes, Audi and Porsche.1*3 However, the fibers are not easily dispersed
in mixing as they tend to clump together. E.I. duPont de Nemours & Co., Inc.
of Wilmington, DE produces Kevlar aramid fiber; however, to date this has not
been used in commercial brake pads or linings. In the future, it might be a
potential candidate for reinforcement of friction materials, if present ex-
perimental tests prove successful.
Other1*0—Various other fibers have been used in phenolic binders, such as
aluminosilicates (wollastonite). However, all have drawbacks and not one of
them is yet as good as asbestos, especially for higher-temperature applications
such as disc brake pads.
Product Substitutes
Special Qualities and Product Composition—
The following materials are currently under development and/or produc-
tion as direct substitutes for asbestos-friction products. Some of these
presently occupy a significant share of the friction materials market for
some applications.
Carbon composites —These materials are made of carbon fiber - reinforced
carbon matrix composites. The fibers are produced by graphitization of organic
or pitch fibers by techniques resulting in parallel alignment of carbon chains
with fiber length providing maximum tensile strength. In one description, the
article is wound up from one or more filaments, resin soaked, and then the
whole part is ultimately carbonized by sintering. The carbonized reinforcing
91
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filaments used here are described as having a greater strength than the car-
bonized resin binder. These filaments can be used for strength alone and to
back an all-carbon friction facing which has no filaments.'*'*
Semimetallics—The major constituent of nearly all semimetallics is iron
which may be in the form of iron particles, steel fiber, or a mixture of both.
For some semimetallics, iron powder is used in conjunction with a small amount
of steel fiber. Property modifiers are added to provide desired performance
characteristics and a resin binder is added to hold the materials together.
Nonabrasive modifiers including cardolite, ground rubber, carbon black, pe-
troleum coke flour, and natural and synthetic graphite are added to control
friction, improve wear, and reduce noise. Abrasive modifiers such as alumina,
silicon carbide, and kyanite are also used to control friction. A typical
semimetallic friction formula may include metallic powder, sponge iron par-
ticles, ceramic powder, steel fiber, rubber particles, graphite powder, and
phenolic resin. Because of the ferrous nature of the product, rust inhibitors
may be added.
Semimetallics were first introduced in the 1960s, primarily to meet
heavy-duty disc brake and extreme duty truck block applications, although they
operate satisfactorily against the ventilated cast-iron rotors in the smaller
brakes of downsized cars and against the solid rotors found in the lighter
brakes of new front wheel drive vehicles. They rely on steel fiber and powder
metallurgy techniques for reinforcement without asbestos. Semimetallics are
stable to temperatures of 400°C (750°F) and exhibit excellent wear resistance.7
Cermets7—Cermet friction materials are composed of metal bonded cera-
mic particles. The metal matrix may be copper or iron. Typical formulae are
presented in Table 20.
Cermets have extremely high thermal stability. Friction is not sufficient
for automobile use and cost is high. They are used extensively in aircraft
and high-speed train brakes. Both carbon fiber and cermet materials are stable
to 700°C (1290°F). One problem is high thermal conductivity, which can exces-
sively heat hydraulic brake fluid causing erratic performance.'l6 This problem
may be avoided by proper design.^ The major problem is low friction. 9
Other—Raybestos-Manhattan Inc. manufactures RAYFLEX, a nonasbestos friction
material for use in oil-cooled transmissions and brake applications in large,
off-the-road vehicles.1*8
Uses and Applications—
Semimetallic, ceremetalics, and carbon composite materials are used in the
friction materials industry as substitutes for asbestos-based friction materials
for heavy-duty applications. 9
The Friction Materials Standards Institute polled its membership early
in 1980 to obtain information on the use of nonasbestos disc brakes.1*9 Results
of this survey are presented in Tables 21 and 22. However, the data does not
specify the exact type of nonasbestos lining used nor the actual prevalence of
92
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TABLE 20. CERMET FRICTION MATERIALS, WT %"*5
Material
Matrix
copper
zinc
tin
nickel
titanium
brass chips
iron
1 23456789 10
47.1 49.6 44.6 44.7 44.9 46.2 52.4 43.6 18.6 46.2
5.5
7.4 3.3
7.1 7.1 7.1 7.0 6.6 6.6 7.1
3.6 3.6 3.6 3.5 3.3 3.3 3.6
28.6
15.0 15.0 8.8
Total 57.8 60.3 55.3 59.7 59.9 56.7 62.3 60.9 57.9 63.8
Friction Material
calcined kyanite 26.1 26.1 26.1 24.9 19.9 25.6 24.0 24.2 26.1 22.0
silica 4.8 4.8 4.8 4.6 4.6 4.8 4.4 4.5 4.8 4.4
Total 30.9 30.9 30.9 29.5 24.5 30.4 28.4 28.7 30.9 26.4
Lubricant
graphite 1.2 1.2 1.2 1.1 6.1 1.1 1.1 1.1 1.2 8.8
lead 2.0 3.7
Total 1.2 1.2 1.2 1.1 6.1 3.1 4.8 1.1 1.2 8.8
Antioxidant
molybdenum 10.0 7.5 12.5 9.5 9.5 9.8 4.6 9.3 10.0 1.0
Total 10.0 7.5 12.5 9.5 9.5 9.8 4.6 9.3 10.0 1.0
-------
TABLE 21. PASSENGER CAR AND LIGHT TRUCK USAGE OF NONASBESTOS DISC BRAKE
PADS1*9 (See Table 22 for Police/Taxi option usage)
Vehicle type
Nonasbestos
lining (with
asbestos back)
Nonasbestos
lining only
American Motors
1980, Spirit, Concord 4's
1980, Spirit, Concord, Eagle 6's
1979, AMX
Buick
1980, Buick Electra
1979-80, Riviera
1980, Regal, Century
1980, Skylark (Power brakes)
1980, Skylark (Manual brakes)
1976-80, Skyhawk
1978-79, Regal, Century (Power brakes)
1978-79, Regal, Century (Manual brakes)
1976-79, Skylark
1976-77, Century (Manual brakes)
1973-75, Apollo (Manual brakes)
Cadillac
1979-80, Eldorado (Diesel)
1979-80, Seville (Diesel)
1968-80, Commercial
Chevrolet
1980, Monte Carlo, Malibu
1980, Citation (Power brakes)
1980, Citation (Manual brakes)
1976-80, Monza
1980, Chevette
1976-80, Camaro
1978-79, Monte Carlo, Malibu (Power brakes)
1978-79, Monte Carlo, Malibu (Manual brakes)
1976-79, Nova
1976-77, Malibu (Manual brakes)
1976-77, Vega
1973-75, Nova (Manual brakes)
Outer only
Outer only
Outer only
I & 0
I & 0
I & 0
Outer only
or
I & 0
I & 0
I & 0
Inner only
I & 0
Outer only
Outer only
Outer only
I & 0
I & 0
I & 0
I & 0
I & 0
or
Outer only
I & 0
I & 0
I & 0
Inner only
Outer only
Outer only
I & 0
Outer only
Outer only
Outer only
(continued)
94
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TABLE 21 (continued)
Vehicle type
Chevrolet Truck
1978-80, El Camino
1979-80, C-, K-, P-20
1979-80, C-, P-30
1979-80, K-30
1979-80, P-30 (JF-9) (Front & Rear)
1979-80, G-30
19.76-78, C-, K-, P-20
1976-78, C-, G-, P-30
Dodge
1978-80, Omni
Dodge Truck
1976-78, Mini Bus
1976, W-300
Ford
1979-80, Fairmont V8
1980, Thunderbird
1979-80, Mustang V8, Turbo 4
1979-80, Fiesta
1980, Mustang V6
Ford Truck
1976-80, F-100 (4 x 4)
1977-80, F-150 (4 x 4)
1976-80, Bronco
1976-78, F-250 (Lt)
1976-80, E-250, F-250 (HD) , E-350, F-350
1980, E-350 School Bus
CMC Truck
1978-80, Caballero
1979-80, C-, K-, P-2500
1979-80, C-, P-3500
1979-80, K-3500
1979-80, P-3500 (JF-9) (Front & Rear)
(continued)
95
Nonasbestos
lining (with Nonasbestos
asbestos back) lining only
I & 0 or
I & 0 or
I & 0
I & 0
I & 0 or
I & 0 or
I & 0
1 & 0
I & 0
1 & 0
I & 0
I & 0
Outer only
I & 0
I & 0
I & 0
I & 0
Inner only
I & 0
I & 0 or
I & 0 or
I & 0
I & 0
I & 0
I & 0
I & 0
I & 0
I & 0
I & 0
I & 0
I & 0
I & 0
-------
TABLE 21 (continued)
1979-80,
1976-78,
1976-78,
Mercury
1979-80,
1980,
1979-80,
1980,
Vehicle type
G-3500
C-,K-,P-2500
C-,G-,P-3500
Zephyr V8
Cougar
Capri V8, Turbo 4
Capri V6
Nonasbestos
lining (with
asbestos back)
I & 0 or
I & 0 or
I & 0
I & 0
I & 0
I & 0
Nonasbestos
lining only
I & 0
I & 0
I & 0
Oldsmobile
1980,
1979-80,
1980,
1980,
1980,
1976-80,
1978-79,
1978-79,
1976-79,
1976-78,
1976-77,
1969-75,
1974-75,
1973-75,
Plymouth
1978-80,
Pontiac
1980,
1980,
1980,
1976-80,
1976-80,
1979-80,
1978-79,
1978-79,
Oldsmobile 98
Toronado
Cutlass
Omega (Power brakes)
Omega (Manual brakes)
Starfire
Cutlass (Power brakes)
Cutlass (Manual brakes)
Omega
Toronado
Cutlass (Manual brakes)
Oldsmobile Commercial
Toronado
Omega (Manual brakes)
Horizon
LeMans , Grand Prix
Phoenix (Power brakes)
Phoenix (Manual brakes)
Sunbird
Firebird (drum rears)
Firebird (organic disc rears)
LeMans, Grand Prix (Power brakes)
LeMans , Grand Prix (Manual brakes)
I & 0
I & 0 or
I & 0
Outer only
Outer only
I & 0
I & 0
I & 0
I & 0 or
I & 0
I & 0
I & 0
I & 0
I & 0
Inner only
I & 0
Outer only
Outer only
Outer only
I & 0
I & 0
Inner only
Outer only
I & 0
Outer only
(continued)
96
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TABLE 21 (continued).
1978-79,
1976-77,
1976-77,
1976-77,
1973-75,
Vehicle type
Phoenix
Ventura
LeMans (Manual brakes)
Astre
Ventura (Manual brakes)
Nonasbestos
lining (with
asbestos back)
Outer only
I & 0
Nonasbestos
lining only
Outer only
Outer only
Outer only
Toyota
1980, Corolla Coupe
I & 0
Key: I
0
Inner Lining
Outer Lining
97
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TABLE 22. POLICE AND TAXI USAGE OF NONASBESTOS DISC BRAKE
PADS ON FRONTS3'"9
Vehicle type
Nonasbestos lining
(with asbestos backing)
American Motors
1978, Concord Police, Taxi
1975-78, Matador Police
Outer only
Both I & 0
Buick
1971-80
1979-80
Chevrolet
Buick Police, Taxi
Century Police
Both I & 0
Both I & 0
1971-80,
1977-79,
1979-80,
Chrysler
1976-80,
1978-80,
1977-80,
Chevrolet Police, Taxi
Nova Police
Malibu Police
Chrysler Police, Taxi
Cordoba Police
LeBaron Police, Taxi
Both I & 0
Both I & 0
Both I & 0
Both I & 0
Both I & 0
Both I & 0
1977-80, Aspen Police, Taxi
1979-80, St. Regis Police, Taxi
1977-80 Diplomat Police, Taxi
1977-78, Monaco Police, Taxi
1977, Royal Monaco Police, Taxi
Both I & 0
Both I & 0
Both I & 0
Both I & 0
Both I & 0
Ford
1978-80, Fairmont Police, Taxi
1976-80 Ford Police, Taxi
1976-80, Granada Police, Taxi
1978-79, LTD II Police, Taxi
Both I & 0
Both I & 0
Both I & 0
Both I & 0
Mercury
1978-80,
1976-80,
1976-80,
Zephyr Police, Taxi
Mercury Police, Taxi
Monarch Police, Taxi
Both I & 0
Both I & 0
Both I & 0
(continued)
98
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TABLE 22 (continued).
Vehicle type
Nonasbestos lining
(with asbestos backing.)
Oldsmobile
1971-80,
1979-80,
Plymouth
1977-80,
1977-80,
1978,
Pontiac
1971-80,
1979-80,
Oldsmobile Police
Cutlass.Police
Volare Police, Taxi
Gran Fury Police, Taxi
Fury Police, Taxi
Pontiac Police, Taxi
Phoenix Police
Both I & 0
Both I & 0
Both I & 0
Both I & 0
Both I & 0
Both I & 0
Both I & 0
Police and Taxi usage of nonasbestos disk brake linings was
as a Police/Taxi option — actual usage depended on customers
ordering that option. Ford-Mercury in 1976-78 also had non-
asbestos disk rears for the Police/Taxi option.
Key: I = Inner Lining
0 = Outer Lining
99
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the asbestos substitute.* In other cases, such as for police cars and taxis,
nonasbestos brake linings were a buyer option, with actual usage depending on
the number of orders placed.
Semimetallic or resin bonded metallic friction materials are presently
used in heavy-duty automotive applications such as police cars and taxis.
Semimetallic disc pads were able to attain overall excellent properties at
both low and high temperatures which ordinary Class A or Class B organics
could not accomplish. Downsizing of vehicles, resulting in smaller front
brakes and higher operating temperatures, mandated the use of semimetallics;
Class A organics gave poor performance and Class B organics made with
asbestos were noisy and scored the rotors. Semimetallics gained acceptance
initially because of their improved performance in spite of a premium price.
Further acceptance came about more recently due to performance combined with
their asbestos-free nature.
Semimetallic drum blocks, first used in air brakes in heavy-duty trucks
used in the logging industry (an extremely severe application), have been
attempted to be scaled down to small drum brakes, but the basic nature of
semimetallics has not lent itself to the accurate segment configuration required
in this application. Here, semimetallics do not possess the necessary green
strength, are difficult to bend into the proper shape, and are more brittle
in cured form and therefore subject to cracking. Modifications to date have
generally resulted in a product that cannot achieve commercially-acceptable
performance characteristics. Work in this area therefore continues. The
first generation of asbestos-free drum linings is currently under evaluation
by vehicle manufacturers.38 While their performance may be superior to asbes-
tos drum brake linings, Semimetallic drum brake linings tend to perform errat-
ically in different temperatures, fade, and produce more noise than asbestos-
based linings. They are more aggressive than asbestos-based linings, that is,
they have higher friction levels and cause more wear. Currently, semimetallics
are 50 to 60 percent more expensive than asbestos linings but with increased
production it is estimated that costs would drop to within 25 percent of as-
bestos brake linings. Approximately 20 percent of passenger cars using disc
brakes in 1977 were equipped with Semimetallic disc brakes as original equip-
ment, ° and it is estimated that in 1985 most original equipment disc brakes
in passenger cars and light trucks will be equipped with semimetallics.
As Table 21 shows, General Motors, in the past, has used a hybrid brake
consisting of one semimetallic and one organic asbestos lining in some mass-
produced passenger cars and light trucks.^ There are actually several ways
in which (asbestos) organic backing materials may be combined with semi-
metallic friction materials. .One combination is the CM hybrid brake discussed,
where there is solid semimetallic friction material on one side of the rotor
and solid organic friction material on the other side. This combination has
*In some years, semimetallics were being phased in and were not included on
all models.
This should not be confused with the use of semimetallic friction materials/
organic backing layers on both the inner and outer pads of some disc brakes.
100
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provided good performance. GM also uses friction materials with no organic
backing layers; instead they are 100 percent semimetallic materials on both
.sides of the rotor and strength is provided by the addition of more fiber,
which allows them to simplify the tooling process. Beyond this, Bendix
makes several types of combinations of friction materials. One is the use
of a semimetallic friction material with an organic backing layer, both of
which are placed on both sides of the rotor. The organic layer helps:
(1) insulate, (2) provide strength to this layer for riveting, and (3) slightly
reduces cost. Bendix also produces a combination featuring 100 percent orga-
nic friction material on one side of the rotor and the semimetallic friction layer
with the organic backing layer, on the other.2 Compared to disc brakes with
asbestos-based friction materials, the hybrid brakes have a higher coefficient
of friction, higher heat resistance, and longer life. This combination is a
compromise in cost and performance compared to a full semimetallic or full
Class B. While some industry sources feel that hybrid brakes will capture
the market because of superior performance, others believe that trends to
lower speed limits and lighter weight cars will reduce the need for high per-
formance brakes. Still others state that fuel-efficient vehicles and front-
wheel drive have increased the need for heavier-duty and smaller brakes that
need the improved performance that only semimetallics have been able to
offer.9 This trend is reflected in Table 21 where, for example,
American Motors reports using a nonasbestos brake lining with an asbestos
back on outer brake positions only on their 1980 Spirits (rear wheel drive) while
Chrysler uses nanasbestos linings with an asbestos back on both inner and outer
brake positions on their 1980 Dodge Omnis (front wheet drive).
The high landing speeds and heavy weights of modern aircraft and high-
speed trains require friction materials with high thermal stability. Cermet
materials possess this property and, for this reason, their share of the air-
craft brake market continues to grow. Currently, nearly 100 percent of all
new commercial aircraft use cermet brake linings.* At the other end of the
spectrum, nearly all new military aircraft use carbon composites, due to the
weight they save and high pressure for performance in these uses.51 As the use
of cermets and full sintered metallics in aircraft brakes began in the 1940s,
they are not new replacements for asbestos; in addition, cermets are not likely
candidates for highway brakes or small clutch facings.1
Cermet materials have also been used for railcar brakes, but, in the
last several years, nearly all railcar brakes have been made of rubber poly-
meric binders with various friction modifiers.52 In general, asbestos and
lead are not present in these brakes.53
Substitute Product Manufacturing Summary—
Manufacturing process—Semimetallic disc pads are made using a dry-mix
process. Ingredients are blended, then formed into briquets at room temperature
and 27.6 to 41.4 MPa (4000 to 6000 psi). The briquets are then hot-pressed at
160° to 180°C (320° to 360°F) for 5 to 15 minutes at 27.6 to 55.2 MPa (4000 to
*0nly the Concorde and possibly one Soviet model use carbon composite.51
101
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8000 psi). The pads are then cured at 220° to 300°C (430° to 570°F) for 4 to
8 hours. Final grinding produces the finished disc pads. Briquets are formed
at 10.3 to 17.2 MPa (1500 to 2500 psi). Briquets may be heated to 90°C
(195°F) for 15 to 30 minutes to reduce blistering during hot pressing. Blocks
are formed by heating at 130°C to 150°C (265° to 300°F) at 13.8 to 20.7 MPa
(2000 to 3000 psi) for 10 to 30 minutes. After cutting to size, blocks are
ground to the appropriate size, followed by curing [unconfined for 15 hours
at 180°C (355°F) or confined for 6 hours at 280°C (535°F)]. The final block
requires grinding, drilling and chamferring.
Cermet materials are manufactured using the powder metallurgy technique.
Desired amounts of individual ingredients are weighed, mixed, compacted, sin-
tered, and coined (or recompacted). The sintering is performed in a reducing
or neutral atmosphere, and the sintering temperature has to be high enough so
that the metal ingredients will adhere to each other.
In carbon composites, carbon or graphite fibers are embedded in a carbon
or graphite matrix. The matrix can be formed by.two methods: chemical vapor
deposition and coking. In the case of chemical vapor deposition, a hydro-
carbon gas is introduced into a reaction chamber in which carbon formed from
the decomposition of the gas condenses on the surface of carbon fibers. An
alternative method is to mold a carbon fiber-resin mixture into shape and
coke the resin precursor at high temperatures. In both of the methods the
process has to be repeated until a desired density is obtained.
Name and number of manufacturers—Table 23 lists nonasbestos brake manu-
facturers, their locations, and the substitute materials they use. Semimetal-
lic disc brake pads and blocks were originally designed and produced by Bendix
Corporation. Bendix has reported that some new equipment was required for their
manufacture.54 Abex Corporation and Raybestos-Manhattan, Inc. also make semi-
metallic disc brake pads.
Cermet materials are manufactured by Bendix Corporation and Abex Corpora-
tion. Abex also makes fiberglass disc brake materials. Carbon composite
brakes are manufactured by Dunlop, Bendix, Goodrich, and Goodyear.9 American
Filler and Abrasives has been marketing an asbestos substitute called Kay-0-Cel,
made primarily of cellulose and clay wastes, which is being tested in brake
linings.45 Kevlar® aramid fiber products are made by E.I. DuPont de Nemours
and Co., Inc., Wilmington, DE. Raybestos-Manhattan makes Rayflex for brakes
in off-the-road vehicles.
Production volumes—Although production figures for individual firms are
not available, it is known that in 1980 semimetallic materials were used in
40 percent of all front disc brakes.55 Cermet materials are used almost ex-
clusively for commercial aircraft brakes and control almost 100 percent of the
current market.51 Kevlar® products are available from a commercial production
facility which is being expanded to 20 million kg/yr capacity. '
*This expansion is for production of aramid fiber products which are not
necessarily friction materials. At present, no company uses Kevlar® in
pads or linings for brake products.9
102
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TABLE 23. NONASBESTOS BRAKE MANUFACTURERS
Manufacturer
Location
Substitute material
Bendix Corp.
Abex Corp.
Raybestos-Manhattan, Inc.
Dunlop
American Filler & Abrasives
Delco-Moraine Div., General
Motors Corporation
E.I. DuPont de Nemours
and Company
Southfield, MI
Troy, NYa
Cleveland, TN
Cleveland, OH
Troy, MI
Winchester, VA
Stratford, CT
Trumbull, CT
England
Bangor, MI
Dayton, OH
Wilmington, DE
Semimetallies
Cermets
Semimetallics
Cermets
Fiberglass
Semimetallics
Carbon composite
Kay-0-Cel
(cellulose and clay)
Semimetallics
Kevlar (aramid)
jDesigned at this location.
This company does not currently manufacture brakes or brake-linings;
rather it is a materials manufacturer who is attempting to evaluate
a new product for friction applications in the experimental stage.1
COST COMPARISON
The basic cost of the substitute friction products involves many complex
factors, including the amount and types of materials used and the basic raw
materials cost. The fixed and variable costs of manufacturing can differ
greatly, based on the type of process and its complexity as well as production
volumes, labor costs, energy costs, and process yield. Administrative costs
and handling/distribution costs are also significant variables as are imple-
mentation costs. Here, it appears that timing of test programs will be impor-
tant as expenses could be minimized by converting to asbestos-free materials
as part of the scheduled new vehicle design programs, where significant brake
system testing is already necessary. Life cycle costs are also a necessary
I consideration; Semimetallics have higher life cycle costs than organics, yet they
are needed on the smaller and lighter vehicles, and these possess better fuel
economy.5
Although exact costs for semimetallic friction materials are not available,
their improved performance compensates for their higher costs due to more
expensive ingredients, higher specific gravity, and more costly processing
103
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requirements. Currently, they are good candidates and have replaced organic
friction materials in disc brakes. Preliminary cost estimates indicate that
asbestos-free brake lining may cost 20 to 25 percent more than current linings
with disc brakes at 20 to 100 percent greater cost. These preliminary esti-
mates are highly dependent on the characteristics of semimetallics making them
extremely difficult and costly to process as drum lining segments. Consequently,
a new class of friction materials is currently under development to suit this
application.38
Cermets cost three to five times as much as asbestos friction materials.
Costs for carbon composites are not available but they are considerably more
expensive than cermets. Kevlar® (aramid) fiber is available in a short pulp
form at $3.75/lb ($8.25/kg). Only small amounts of this fiber are reported to
be required with deep filler materials, making the cost between 20 and 40
percent greater than for asbestos, with lifetime costs approaching those of
asbestos. Table 24 lists the costs of various fibers proposed as substi-
tutes for asbestos in friction material.
TABLE 24. COSTS OF MATERIALS PROPOSED AS SUBSTITUTES
FOR ASBESTOS IN FRICTION MATERIALS
57,a
Material
Price - $/lb ($/kg)
Asbestos
Fibrous glass
Mineral wool
Potassium titanate fibers
Graphite and carbon fibers
Wollastonite
Aramid fibers
0.05 - 0.15 (0.11 - 0.33)
0.50 - 0.75 (0.11 - 1.65)
0.15 (0.33)
1.00 - 1.25 (2.20 - 2.75)
10.00 - 12.00 (22.00 - 26.50)
0.15 (0.33)
3.75 - 8.00 (8.25 - 17.65)
Prices should be used for comparison only. Dollars are 1978 U.S.
CURRENT TRENDS
The need for more energy-efficient automobiles and trucks has put an in-
creased demand on friction materials. Major trends are towards smaller,
lighter, more efficient vehicles with manual transmissions and smaller brakes.
Although organic friction materials will continue to serve the drum brake in-
dustry, more and more vehicles are being equipped with ventilated disc brakes.
Ventilated brakes may be replaced by solid rotor disc brakes to save weight. As
brakes become smaller, braking temperatures become higher. Class B organic
and semimetallic friction materials will replace Class A organics because they
have higher thermal stability. Heavy vehicles are using more and more effi-
cient disc brakes. More cermet friction materials will be used in heavy-duty
clutches. The trend in aircraft brakes may be toward lighter carbon composite
materials.
104
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Because of present and future health standards, some automobile manu-
facturers are in favor of removal of asbestos and lead from brakes.58 U.S.
automakers have cut the average asbestos content of disc brake linings from
0.45 kg to about 28 grams, with the remaining asbestos present in the backing
layer.9 Both General Motors and Ford have asked their suppliers to seek
ways to totally eliminate asbestos from disc brakes. Because of the curved
shape required for drum brakes, no suitable substitute for asbestos is readily
available. However, Rockwell International Corporation, manufacturer of about
60 percent of the brakes used in heavy trucks, has a major development effort
aimed at obtaining asbestos-free friction materials from suppliers.58
Borg-Warner Corporation,59 Bendix,3" and Abex Corporation13 (among others)
have developed proprietary substitutes for automobile brake friction materials.
Some are in the consumer testing stage, but no additional information is avail-
able at this time. A company such as Bendix is not aggressively pursuing
licensing policies but does have many license agreements for the international
market which usually include territorial exclusions. Significant company* funds
have been expended to develop this new technology. Borg-Warner has spent
several million dollars to develop asbestos-free friction materials for em-
ployee safety and may enter license agreements or manufacture in Brazil.59
Although Raybestos-Manhattan, Inc. stated publicly in May 1979 that the company
would "halt" the manufacture of brake linings and other parts that contain
asbestos by using a blend of 10 to 15 components (40 percent fiber, 20 percent
resin binder, and 40 percent friction modifiers), discussions with company
representatives revealed that this was not strictly true.11 The company has
developed some nonasbestos substitute products for certain applications and
has committed itself to a search for nonasbestos substitutes, but the complete
removal of asbestos from their friction materials is not expected in the
foreseeable future. Small brake lining manufacturers have a real problem with
capital equipment and financing of nonasbestos friction products.5
Part of the problem in designing new brake systems is simply that it takes
time. Both the materials used and their properties are a result of optimiza-
tion procedures, with extensive testing programs both by the material supplier
and by the customer to ensure suitability, quality, and regulatory confonnance.
For evolutionary changes, an example of which would be an improved organic disc
pad utilizing the same basic components (asbestos, resin, and modifers) but
with better wear, improved fade resistance and the same friction and noise
properties, years are required. In this case, asbestos organic linings are
essentially the product of 40 years of evolutionary changes. Supplier develop-
ment and validation testing requires 18 to 24 months, consumer application
testing 12 to 18 months, and 6 months manufacturing lead-time, or, a total of
3 to 4 years for one evolutionary change. In addition, there are revolution-
ary changes, which actually advance the state-of-the-art, that are more dif-
ficult to come by, and are even longer in the developmental phases. It is
*Bendix Corporation.36
105
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unrealistic to apply a timetable to inventions, but for establishing the fea-
sibility of a new concept, 12 to 18 months is a reasonable time period to be
expected. Reducing that concept to a product with some or most of the basic
characteristics can take another 12 to 24 months. Formulation development
for commercial application and validation of properties adds 24 to 36 months.
An additional 12 to 18 months is required for customer application testing
plus 6 months manufacturing lead-time, or a total change-over requiring 5% to
8% years. Eliminating asbestos from automotive friction materials is consid-
ered a revolutionary change. As ideas on substitute products came into being
around 1975 and later, the first evolutionary changes are now underway to
help develop a second generation of materials which have improved properties
and the multiple types and assortment of formulations necessary for different
applications.38
As indicated, semimetallic disc brake pads without asbestos in either
the friction material or the backing layer are currently in use, but cannot
be used in all vehicle applications. An orderly transition is expected to
occur, approaching 100 percent utilization by 1985. Development of asbestos-
free organic disc-brake pads and semimetallic drum brake linings is contin-
uing at Bendix with production implementation not yet able to be predicted.
In addition, Bendix and others are in the final development stage of work on
first generation asbestos-free organic drum-brake linings and some asbestos-
free blocks are available commercially for heavy-duty applications, with the
first significant production release expected in 1982. All of these new de-
velopments show continued effort from industry to move towards a dominance of
asbestos-free products in the friction materials area.
CONCLUSION
Semimetallic disc brake friction materials, originally designed and pro-
duced by Bendix Corporation and now also manufactured by Delco-Morraine, Abex,
and Raybestos-Manhattan, are expected to increase market share relative to
asbestos disc brake materials. In fact, it is projected50 that in 1985 nearly
all original equipment disc brakes made for passenger cars and light trucks
will be equipped with semimetallics.
At the present time a nonasbestos product for drum brake linings for pass-
enger cars is not available commercially. However, intense research in this
area is underway, with specifics still proprietary at this time. The first
commercially-available nonasbestos drum lining may contain some combination
of steel fibers, synthetic fibers, cotton, ceramic, carbon, natural materials, glass,
and mineral fibers. For this model year 1980, commercial nonasbestos linings
were not available50 for drum brakes; however, Bendix Corporation is appar-
ently very close to marketing this kind of product.
As for cermet brake linings, once the problem of their interaction with
hydraulic brake fluid can be solved, their use may grow in the heavy-duty
clutch field. Cermets are not likely candidates for replacement of passenger
car or light-truck brakes.1 With all of the current research into brake
lining substitutes, a nonasbestos product for more universal use should become
available in the future.
106
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Clearly, the design of the entire braking system has a great influence
on the types of friction material that can be used. The lack of readily avail-
able nonasbestos drum brake linings contrasted with the progress toward totally
asbestos-free disc brake pads underscores this point. However, redesign
appears to be given less consideration than the search for a material to re-
place asbestos for the following reasons:
• Brake systems in use have been time tested and proven
effective. Changes in the existing systems would
require that the system and the asbestos replacement
both be tested intensively.* Problems could result if
replacements are not made of materials similar to those
of the original equipment, as the entire brake system is
designed as a unit. Without careful study, substitution
may cause safety or wear problems. Time is often needed
to heal these faults. Testing requirements are signifi-
cantly reduced if only the asbestos substitute is to be
evaluated.
• Any new brake system must be suitable to be maintained
by automobile dealers and service stations. Any complex
new system or radical changes in brake system construc-
tion that would be difficult to maintain properly would
be unacceptable.
« Equipment designed to produce brake systems currently in use
would either have to be replaced or modified to produce a
new brake system, possibly necessitating large capital expen-
ditures at a time the automotive industry is feeling finan-
cial constraints.
• The many manufacturers of brake linings must respond to the
needs of their customers. Until the automobile manufacturers
supply different product specifications, as for the friction
material component of a new braking system, the brake lining
manufacturers will continue to supply a traditional product.
Brake system changes must be initiated by original equipment
manufacturers. "I"
*This problem is reported to be even greater for suppliers and users of fric-
tion materials in the nonautomotive field. In many instances, these clutches
and brakes were manufactured 10 to 40 years ago and the testing facilities of
the manufacturer have been dismantled. In other cases the volume of replace-
ment friction materials is so low that the manufacturer of the clutches and
brakes cannot afford to set up test programs to evaluate friction materials
even if the test facilities were available. This is true for commercially
acceptable asbestos-based friction materials and probably even more true for
untried nonasbestos friction materials.1
The information presented here is taken in part from Reference 38.
107
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It is much easier, more readily acceptable and much less risky for brake
lining manufacturers to attempt to find a substitute for asbestos rather than
effect a complete redesign of braking systems. Consequently, most research
is focussed on the search for substitutes.
The outlook for the use of asbestos in friction material is, at best,
mixed. The majority of the industry's products are used in passenger auto-
mobiles and, as such, are influenced by the vagaries of the buying public:
if a lot of new cars are being sold, a lot of new brakes will be required.
Conversely, if fewer new cars are sold, more used cars in the marketplace
will result in more sales of replacement brake friction materials. Further
uncertainty is introduced by the American automobile manufacturers' avowed
intentions to eliminate asbestos from original equipment brakes by the 1985*
model year. If successful substitutes are found, asbestos consumption in
friction materials will drop precipitously. The target date set for 1985
represents the culmination of a carefully thought-out phased production pro-
cess on the part of friction materials producers. The use of asbestos in
friction materials is likely to continue in industrial equipment such as
brake blocks and clutch facings for lathes, presses, hoists, etc. (more limited
demand) while asbestos-free products are developed for the automotive industry.
*Raybestos-Manhattan plans to eliminate asbestos from its friction material
products by 1982.6°
108
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REFERENCES
1. AIA comments to GCA Draft Final Asbestos Substitutes Performance
Analysis Report. Received October 22, 1981.
2. Telecon. M. G. Jacko, Bendix Materials Center, with Nancy Krusell,
GCA/Technology Division, November 23, 1981. Notebook No. 1-619-018-012,
p. 5.
3. Michaels, L., and S. S. Chissick. Asbestos - Volume 1: Properties
Applications and Hazards. New York. John Wiley and Sons. 1979.
pp. 95-103.
4. Twiss, S. B., and E. J. Sydor. U.S. Patent 3,007,890. November 7, 1961.
Rewarded to Chrysler Corporation.
5. Jacko, M. G., and R. T. Du Charme. Brake Emissions: Emission Measure-
ments from Brake and Clutch Linings From Selected Mobile Sources. U.S.
Nat. Tech. Information Service, PB-222-372.
6. Clifton, R. A. Preprint from the 1980 Bureau of Mines Minerals Yearbook.
Asbestos. U.S. Department of the Interior, p. 4.
7. Jacko, M. G., and S. K. Rhee. Brake Linings and Clutch Facings. Encyclo-
pedia of Chemical Technology, Third Edition, Volume 4. New York.
John Wiley and Sons. 1979, pp. 202-212.
8. Bark, L. S., D. Moran, and S. J. Percival. Chemical Changes in Asbestos-
Based Friction Materials During Performance - A Review. Wear. 34:131-139.
1975.
9. Jacko, M. G., Bendix Materials Center. Review of Friction Materials
Section of GCA Draft Final Asbestos Substitutes Performance Analysis Report.
July 16, 1981.
10. Meylan, W. M., et al. Chemical Market Input/Output Analysis of Selected
Chemical Substances to Assess Sources of Environmental Contamination:
Task III - Asbestos. EPA-560/6-78-005. August 1978. pp. 61, 63-65, 100.
11. Telecon. Raybestos-Manhattan, Inc. with David Cook, GCA. February 28,
1980. Friction products manufactured.
12. Telecon. Kevin Peppard, Bendix Corporation, with David Cook, GCA.
February 28, 1980. Notebook No. 1-619-007-02, p. 66. Friction product
manufactured.
109
-------
13. Telecon. George Bason, Abex Corp., with David Cook, GCA. February 11,
1980. Asbestos substitutes in friction materials.
14. Telecon. Tom Nick. Delco-Moraine Division of General Motors Corporation,
Dayton, OH. (513) 227-5000, with Anne Duffy, GCA Corporation, GCA/Tech-
nology Division. April 14, 1981, Call No. 7.
15. Telecon. Mr. Sleeth, H. K. Porter Company, with Robert Bouchard, GCA.
February 29, 1980. Friction products manufactured.
16. Telecon. Terry Elaine, Borg-Warner Corporation, Spring Division with
Robert Bouchard, GCA. March 4, 1980. Friction products manufactured.
17. Telecon. Roy Huckabee, Nuturn Company, with Robert Bouchard, GCA.
February 29, 1980. Friction products manufactured.
18. Telecon. Earl Fygert, National Friction Products Corporation, with
Robert Bouchard, GCA. February 29, 1980. Friction products manufactured.
19. Telecon. Bill Shine, Auto Specialists Manufacturing Company, with
Robert Bouchard, GCA. February 29, 1980. Friction products manufactured.
20. Telecon. Standee Industrial with Robert Bouchard, GCA. February 28,
1980. Friction products manufactured.
21. Telecon. Jack Payton, Friction Products Company, with Robert Bouchard,
GCA. February 29, 1980. Friction products manufactured.
22. Telecon. Andrews, Royal Industrial Brake Products, Inc. with Robert
Bouchard, GCA. February 28, 1980. Friction products manufactured.
23. Telecon. Montgomery, Reddaway Manufacturing Company with Robert
Bouchard, GCA. February 29, 1980. Friction products manufactured.
24. Telecon. Molded Industrial Friction Corporation with Robert Bouchard,
.GCA. March 3, 1980. Friction products manufactured.
25. Telecon. Wheeling Brake Block Manufacturing Company with Robert
Bouchard, GCA. February 29, 1980. Friction products manufactured.
26. Telecon. Reginal D. Kelley, Force Control Industries, with Robert.
Bouchard, GCA. March 3, 1980. Friction products manufactured.
27. Telecon. Brassbestos Manufacturing Corp. with Robert Bouchard, GCA.
March 3, 1980. Friction products manufactured.
28. Telecon. Paul Biondo, Auto Friction Corp., with Robert Bouchard, GCA.
March 3, 1980. Friction products manufactured.
29. Telecon. Robert Randolf, Gatke Corporation, with Robert Bouchard, GCA.
March 3, 1980. Friction products manufactured.
110
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30. Telecon. Lasco Brake Products Company with Robert Bouchard, GCA.
March 3, 1980. Friction products manufactured.
31. Telecon. Appollageno, MGM Brakes, Inc., with Robert Bouchard, GCA.
March 3, 1980. Friction products manufactured.
32. Telecon. Carlisle Corporation with Robert Bouchard, GCA. March 3, 1980.
Friction products manufactured.
33. Telecon. Thiokal Chemical Corporation with Robert Bouchard, GCA.
March 3, 1980. Friction products manufactured.
34. Telecon. Mr. Baltz, Baltz Company, Inc. (distributors for Eaton Cor-
poration), with Robert Bouchard, GCA. March 4, 1980. Friction products
manuf ac t ur ed.
35. Telecon. Bill Ferk, Scan-Pac Manufacturing Company, Mequon, WI
(414) 241-3890, with Nancy Krusell, GCA Corporation, GCA/Technology
Division. April 22, 1981. They also have a plant in Lexington, KY
but do not use asbestos there.
36. Additional company information added October 1981, from Telecons to
Bob Pigg, AIA, and Ed Drislane, Friction Materials Standards Institute,
with Nancy Krusell, GCA/Technology Division. Notebook No. 1-619-007-9,
p. 148.
37. Clifton, R. A. Asbestos. United States Bureau of Mines. Washington,
D.C. Mineral Commodity Profile. July 1979, p. 9; also, preprint from
Clifton's 1978-79, and 1980 Bureau of Mines Minerals Yearbook.
38. Jacko, M. G., C. M. Brunhofer, and F. W. Aldrich. Nonasbestos Friction
Materials. Speech presented at the EPA/CPSC Substitutes to Asbestos
Conference, July 14-16, 1980, Arlington, VA. Found in Proceedings of
the National Workshop on Substitutes for Asbestos. GCA, November 1, 1980.
39. Loken, H. Y. (E.I. DuPont de Nemours & Co., Inc.). Asbestos Free Brakes
and Dry Clutches Reinforced with Kevlar Aramid Fiber, SAE Technical Paper
Series. Paper presented at Earthmoving Industry Conference, Peoria, IL,
April 14-16, 1980.
40. Pye, A. M. A Review of Asbestos Substitute Materials in Industrial
Applications. Journal of Hazardous Materials. (Netherlands). _3:137-138.
1979.
41. Hayes, J. S., American Kyanol Incorporated, letter to George A. Peters,
Registered Professional Engineer, November 20, 1979.
42. U.K. Patent Application GB2018806A, filed 22 August 1978.
Ill
-------
43. Moulton, E.I. DuPont de Nemours & Co., Discussion During Friction
Products Roundtable Session, EPA/CPSC "Substitute to Asbestos"
Conference, Arlington, VA, July 14-16, 1980.
44. U.S. Patent No. 3,552,533. Carbonized Friction Article. Inventors:
J. Nitz, G. Graham. Patented January 5, 1971. Assignee: Abex Corp.,
New York, N.Y.
45. Allen, A. W., and R. H. Herron. U.S. Patent 2,948,955. August 16, 1960.
46. Green, A. K., and A. M. Pye. Asbestos Characteristics, Applications,
and Alternatives. Fulmer Research Institute, Fulmer Special Report
No. 5, ISSN 0427-7457. 1976.
47. Telecon. Wayne Quasar, Westinghouse Air Brake Company, with Nancy Krusell,
GCA. November 19, 1979. Cermet brakes.
48. /'Annual Reports - 1979 Raybestos-Manhattan." Asbestos, V. 61,
N. 11, p. 14, May 1980.
49. Drislane, E. W., Executive Director, Friction Materials Standards
Institute, letter to Richard Guimond, EPA OPTS, undated, received at
EPA April 21, 1980.
50. Telecon. M. G. Jacko, Bendix Materials Center, with Nancy Krusell, GCA.
August 1979. Semimetallic Disc Brake pads.
51. Telecon. Norris A. Hooton, Director of Engineering, Bendix Brake &
Strutt, (219) 237-2801, with Nancy Krusell, GCA/Technology Division,
November 25, 1981. Notebook No. 012, p. 25.
52. Telecon. Jack Reynolds, Johns-Manville, with David Cook, GCA.
February 19, 1980. Railcar brakes.
53. Telecon. Leon Kopyt, Mass Transit Systems Corporation, with David Cook,
GCA. February 19, 1980. Railcar brakes.
54. Proceedings of the National Workshop on Substitutes for Asbestos
July 14-16, 1980. Friction Roundtable Session, remark made by
Mr. Brunhofer of Bendix, p. 197.
55. Telecon. M. G. Jacko, Bendix Materials Center, with David Cook, GCA.
March 3, 1980. Brake compositions.
56. Drislane, M. Friction Materials Standards Institute (FMSI), Mr. Ward
(GM) and Mr. Brunhofer (Bendix). Roundtable Discussion for Friction
Products, USEPA/CPSC. "Alternatives to Asbestos" Conference, Arlington,
VA. July 14-16, 1980. Presented in Proceedings of the National Work-
shop on Substitutes to Asbestos. GCA, November 1980.
57. Telecon. Eugene Conner, Johns-Manville, with David Cook, GCA.
January 17, 1980. Asbestos prices.
112
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58. Business Week. "The Growing Need for Asbestos Substitutes." Business
Week, December 3, 1979, p. 98D.
59. Telecon. Robert Curran, Borg-Warner Corp. , with David Cook, GCA.
February 11, 1980. Asbestos substitutes in friction materials.
60. Castleman, Barry, and S. L. Berger. Asbestos Substitute Technology.
July 8, 1980.
113
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SECTION 4
ASBESTOS CEMENT PIPE
ASBESTOS PRODUCT
Special Qualities
Asbestos Cement (A/C) pipe products are strong, resilient, flexible,
durable, and corrosion resistant. A/C.pipe may also be said to be nearly
inert (it is subject to certain corrosive media).and, when used inside
buildings for drain, waste and vent applications, it is fire resistant.
Asbestos imparts not only important flexural strength in pipe (allowing for a
certain amount of deflection without failure) but also gives the pipe
structural integrity so that it may withstand crushing loads and constant and
transient hydrostatic pressure.^ The laminar structure of the pipe, which
results from the basic method of manufacturing, also contributes to greater
strength.* This allows for easy tapping for lateral lines or other connectors
without a loss of strength. Because of the nature of the raw materials
(Portland cement, ground silica and asbestos fibers) used to manufacture A/C
pipe, it resists corrosion and most chemical action and is not subject to
electrolysis.
The primary purpose of asbestos fibers in A/C pipe is to act as a
reinforcing agent. The properties that make asbestos suitable as a
reinforcing agent are its high fiber strength, resistance to alkali attack and
adhesion to cement. The raw fibers are also readily wetted and thus
contribute favorable and controllable drainage properties to an asbestos
cement mix, enabling A/C pipe to be produced by a relatively simple and
flexible process similar to that used in paper-making.2 Asbestos can also
withstand the autoclave (heat and pressure) process used in the manufacture of
pipe and resists the alkali attack of Portland cement. The large surface area
of asbestos fibers promotes good adhesion between the cement mixture and the
fiber surface.
*Data from unpublished OSHA report on asbestos,
114
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Product Composition
The AWWA^ defines A/C pipe as a mixture of either:
1. Portland cement or Portland blast furnace slag cement and asbestos
fiber, with or without silica.
2. Portland pozzolana cement and asbestos fiber.
If the pipe material simply sets under relatively normal ambient
conditions* (Type I), representative formulations are 15 to 25 percent
asbestos and 75 to 85 percent cement; however, if the pipe is "cured" by
autoclave (Type II) (as is practiced in the U.S.) silica is added so that the
representative formulation becomes 15 to 25 percent asbestos, 42 to 53 percent
cement, and 34 to 40 percent silica. Finely ground solids from crushed
damaged pipe may be added in quantities up to 6 percent as filler material.**
In 1980, it was estimated that 83 percent of the asbestos used in A/C pipe was
chrysotile (119,700 metric tons), 17 percent was crocidolite (24,100 metric
tons), and 0.1 percent was amosite (200 metric tons).^
A/C water pipe is classified on the basis of its design internal pressure
ranging from 2070 to 6200 kPa and its chemical composition as follows:
• Type I - No limit on uncombined calcium hydroxide
e Type II - 1 percent or less uncombined calcium hydroxide
There is a separate classification for A/C sewer pipe based on resistance to
external crushing loads. The chemical composition of the pipe bears no
revelance to its pressure class rating, but rather to its method of
manufacture. •"- The pipe's ability to withstand attack (which might result in
the release of asbestos fibers) from "aggressive""'" water depends on chemical
type. Only Type II is recommended for moderately aggressive water whereas
either can be used for nonaggressive water. In aggressive water applications,
the serviceability of Type II pipe must be established by the purchaser in
conjunction with the manufacturer (AWWA spec. C-400).^- For external
corrosion from ground water, in addition to acidity, soluble sulfate is an
important parameter.-'
Conditions for this pipe to set include total immersion in water for a period
of approximately 28 days.
**Data from unpublished OSHA report on asbestos.
tAggressiveness is computed from pH + log (AH) where A is the total alkalinity
and H the total hardness, both expressed as ppm
115
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Uses and Applications
The majority of the A/C pipe produced is used for water mains (pressure
pipe) and sewer lines (nonpressure pipe). An indeterminate, smaller amount of
A/C pipe is also used as conduits for electrical and telephone cables and for
laterals from street mains to the consumer. The exact historical accounting
of A/C pipe is unavailable as this information is considered confidential or
unknown.
Over the 6-year period from 1974 to 1980, asbestos-cement pipe jumped
from 10.8 percent of pipe in place in 1975 to 13.9 percent in 1980. More
dramatically, while in 1974, 29.8 percent of all pipe installed was A/C, by
1980, A/C pipe jumped to 40.4 percent.5 Most (72 percent) of the A/C pipe
installed as water main is 6 to 12 inches in diameter. Tables 25 and 26 show
a comparison of the different types of pipe used as water mains."
The mileage of sewer mains in systems serving more than 2,500 people was
estimated to be 737,100 km by a 1975 American City Magazine study.? The
study did not make a distinction between sanitary, storm, or combined sewers
while estimating that A/C pipe accounted for only 5.4 percent or 40,200 km of
this total. Over 77 percent of the A/C pipe was in the 8 to 14 inch
category. Tables 27 and 28 provide a comparison of the pipes in use.
Product Manufacturing Summary
Manufacturing Process—
The manufacture of A/C pipe is a wet process, similar to cellulose paper
production. The ingredients—asbestos fibers, Portland cement, silica
sand—are weighed and added to a dry mixer. The mixed ingredients are added
to a beater; water is added producing an A/C slurry containing about 97
percent water.
This slurry is filtered through rotating screens, forming a cement-fiber
ply which is picked up by continuous felt, dewatered by vacuum boxes and
accumulated on a steel cylinder called a mandrel. The plys are wound around
the mandrel under several tons of pressure and compressed into a dense,
homogeneous pipe wall. At the proper thickness, the rolling up process
stops. The pipe, now in 3 meter (10 foot) or 4 meter (13 foot) lengths, is
then precured under controlled heat and humidity. After mandrel removal, it
is final cured by water immersion (for Type I) or high pressure steam
autoclaving (for Type II). Autoclaving reduces the free lime content,
enhancing corrosion resistance to high sulfate soils .and waters. The pipe is
then finished by precision machining the ends.^
A/C pipe may be lined prior to final shipment. The pipe is lined to
protect the pipe from aggressive or corrosive fluids. Although a vinyl lining
was often employed in the past, the use of vinyl for lining material has
virtually ceased in favor of gilsonite, asphaltic-based or proprietary
coatings.1
116
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TABLE 25. TYPES OF WATER MAIN PIPE NOW IN PLACE (1975)-NATIONAL PROJECTIONS
OF MILEAGE*5
Population range
served
Over 1,
500,000
250,000
100,000
50,000
25,000
10,000
000,000
- 999
- 499
- 249
- 99
- 49
- 24
2,500 - 9
Total Mileage
Percent
,999
,999
,999
,999
,999
,999
,999
of Total
Cast
and
ductile
iron
43
46
43
65
54
56
84
87
481
75
,388
,176
,628
,431
,905
,870
,044
,373
,815
.3
Asbestos
cement
2,982
11,150
7,552
7,703
7,793
11,660
15,008
20,023
83,871
13.1
Steel
1,292
4,158
5,992
3,230
3,862
5,235
6,559
7,524
37,852
5.9
Reinforced
concrete
1
1
1
1
1
1
1
10
,441
,197
,498
,325
,545
,348
,001
728
,083
1.6
Plastic
1
1
250
1,408
211
714
2,334
2,063
6,982
1.1
Other
596
315
3,495
3,727
1,895
3.490
2,223
3,641
19,382
3.0
Total
48,700
62,997
62,415
82,824
70,211
,317
111,169
121,352
639,985
100.0
*For comparison with the 1975 data presented here, Installed A/C pipe accounted
for 40 percent of the water pipe business in 1980, with cast iron at 44 percent.1
NOTE: Cast iron is the predominate type of pipe now in place, accounting for
three-fourths of the total. Part of the reason for this large amount may
also be credited to the fact that cast iron pipe has been sold for 200
years. Asbestos cement has a 13 percent share with none of the other types
having more than 6 percent; A/C has been on the market for 50 years.1
-------
TABLE 26. WATER MAIN SIZE RANGES BY TYPE OF PIPE NOW IN PLACE-PROJECTED
TOTALS (1975) (Percentage of Total in Parentheses)°
Type
Cast and ductile
iron
Asbestos Cement
Steel
Reinforced concrete
Plastic
Other
Under
6"
75,701
(15.1)
8,088
( 9.7)
20,223
(53.4)
17
( 0.2)
4,330
(62.0)
7,510
(38.7)
6" - 12"
369,761
(76.7)
72,402
(86.3)
11,171
(29.5)
416
( 4.1)
2,607
(37.3)
8,829
(45.6)
13" _ 24"
31,645
( 6.6)
3,365
( 4.0)
4,049
(10.7)
4,374
(43.4)
40
( 0.6)
2,477
(12.8)
Over
24"
4,709
( 1.0)
16
( * )
2,409
( 6.4)
5,276
(52.3)
4
( 0.1)
566
( 2.9)
Total
481,816
(100.0)
83,871
(100.0)
37,852
(100.0)
10,083
(100.0)
6,981
(100.0)
19,382
(100.0)
*Less than one-tenth of 1 percent.
NOTE: The great majority of cast iron and asbestos cement pipe
falls within the 6" to 12" range. Larger sizes predominate
in reinforced concrete with over half of this mileage over
24" in diameter. Plastic pipe lies almost exclusively in
the two smallest ranges with negligible mileage over 12".
Somewhat more than half of the steel total is under 6"
but this type also has significant mileage of large-sized
pipe.
118
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TABLE 27. TYPE OF SEWER MAIN PIPE NOW IN PLACE-NATIONAL PROJECTIONS
OF MILEAGE (1975)7
Population range
served
Over 500,000
250,000
100,000
50,000
25,000
10,000
- 499
- 249
- 99
- 49
- 24
2,500 - 9
Total Mileage
Percent
,999
,999
,999
,999
,999
,999
of Total
Cast
and
ductile
iron
547
434
802
1,129
1,512
1,606
9,067
15,097
3.3
Asbestos
cement
1,504
521
601
2,207
6,317
4,435
9,182
24,767
5.4
Vitrified
clay
41
33
28
36
30
55
80
306
66
,631 .
,456
,109
,393
,722
,211
,913
,435
.8
Reinforced
concrete
17,
2,
14,
10,
9,
10,
9,
74,
16
979
343
080
369
395
782
411
359
.2
Plastic
205
521
1,002
616
1,998
918
4,132
9,392
2.1
Other
6,494
6,118
5,512
616
4,049
3,517
2,066
}
28,372
6.2
Total
68,360
43,393
50,106
51,330
53,993
76,469
114,771
458,422
100.0
NOTE: Vitrifi'ed clay is the predominate type of pipe now in place, ac-counting for
two-thirds of the total. Reinforced concrete has a 16 percent share with
none of the other types having more than 6 percent if the total. The
majority of pipe within the "other" category is of the unreinforced con-
crete category.
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TABLE 28. SEWER MAIN SIZE RANGES BY TYPE OF PIPE NOW IN PLACE-PROJECTED
TOTALS (1975) (Percentage of Total in Parentheses)7
Type
Cast and ductile
iron
Asbestos cement
Vitrified clay
Reinforced concrete
Plastic
Other
Under
8"
4,006
(26.5)
3,171
(12.8)
55,626
(18.2)
4,256
( 5.7)
864
( 9.2)
6,354
(22.4)
8" - 14"
8,805
(58.3)
19,248
(77.7)
208,498
(68.0)
29,283
(39.4)
7,756
(82.6)
13,864
(48.9)
15" - 24"
1,958
(13.0)
2,071
( 8.4)
33,341
(10.9)
17,587
(23.7)
447
( 4.7)
4,182
(14.7)
Over
24"
328
( 2.2)
277
( 1.1)
8,970
( 2.9)
23,233
(31.2)
325
( 3.5)
3,972
(14.0)
Total
15,097
(100.0)
24,767
(100.0)
306,435
(100.0)
74,359
(100.0)
9,392
(100.0)
28,372
(100.0)
NOTE: Over half of reinforced concrete sewer pipe in place is
over 14" in diameter. At the other extreme, plastic pipe
is almost all under 15" with 83 percent between 8" to 14".
The size distributions for cast iron, asbestos cement, and
vitrified clay are more representative of sewer main pipe
as a whole.
120
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Name and Location of Manufacturers—
The primary domestic producers of A/C pipe are listed below:
• Johns-Manville
Ken-Caryl Ranch
Denver, CO 80217
• CertainTeed Corporation
120 E. Lancaster Avenue
Ardmore, PA 19003
* CAPCO Pipe Co., Inc.
P. 0. Box 3435
Birmingham, AL 35205
A/C pipe is produced by J/M in:°
• Denison, TX
• Long Beach, CA
• Stockton, CA
CertainTeed locations include:
• Santa Clara, CA
• Hillsboro, TX
• Ambler, PA
• Riverside, CA
CAPCO is located in Ragland, AL and Van Buren, AR.^
Production Volumes—
Recent A/C pipe production figures are unavailable. A request for such
figures from the A/C Pipe Producers Association was not answered. ^ The
producers regard this information as proprietary, and are reluctant to provide
exact numbers.
Searches through literature and government reports showed a wide
disparity between production and fiber use. One estimate, by the Bureau of
Mines^ places the 1980 fiber use at approximately 144,000 metric tons.
121
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SUBSTITUTE PRODUCT
Methodology
Search Strategy—
The primary objective of this survey was to gather current information on
substitute product properties and availability. The survey began with a
review of the available secondary sources to obtain a background as to what is
known about A/C pipe and its substitutes and what must be verified to complete
the assessment.
Journals and magazines were searched for industry contacts and a listing
of the applicable Trade Associates was obtained. Calls to the Trade
Association provided necessary information and new contacts. Every possible
effort was made to obtain and verify the most recent information.
No plant trips were made during this task. However, under a previous GCA
contract, a plant visit was made to an A/C pipe plant and the trip report was
reviewed for applicable information.
Summary of Contacts—
A partial list of the primary contacts is as follows:
• Mr. Steve Shea
Boston Sewer and Water Commission
Boston, MA
• Mr. Stan Mruk
Plastic Pipe Institute
New York, NY
« Mr. Richard Bogdanovich
American Waterworks Association
Denver, CO
• Mr. John Matticks
Department of Commerce
Washington, D.C.
9 Mr. Phil Caldwell
Cem-Fil Corporation
Nashville, TN
• Mr. Robert Walker
Uni-Bell Plastic Pipe Association
Dallas, TX
• Mr. Gene Owen
American Cast Iron Pipe Company
122
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• Mr. John 0"Conner
American City Magazine
Pittsfield, MA
• Mr. Mike Higgins
Ductile Iron Pipe Research Association
1301 W. 22 St.
Oakbrook, IL 60521
a Mr. Harry Miles
Ductile Iron Pipe Research Association
Jericho, VT
• Mr. Russell Preuit
American Concrete Pipe Association
Vienna, VA
• Mr. Ed Sikora
National Clay Pipe Association
Crystal Lake, IL
Fiber Substitutes
Manufacturers of pipe products have searched for fibers which could be
substituted for asbestos as a concrete reinforcing agent. For general
applications, a substitute fiber should be strong, resistant to alkali attack,
compatible with current manufacturing equipment, and cost competitive. Of the
fibers considered here, only special glass fibers have been employed in a
commercial product. A comparison of properties of asbestos and four
substitute fibers was tabulated and is presented in Table 29.
Asbestos demonstrates excellent reinforcing ability. Steel fibers also
have demonstrated outstanding reinforcement abilities. Carbon fibers have
strength, elasticity, and chemical resistance but lack the cohesion necessary
for proper binding.*
Steel Fibers—
Special qualities—As Table 29 shows, steel fibers have many properties
which could make them suitable as a replacement for asbestos including high
strength and good cohesion properties.
*Source is an unpublished document by OSHA on asbestos,
123
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TABLE 29. PROPERTIES OF VARIOUS FIBERS FOR USE IN PIPE PRODUCTS*
Type of , , , Fiber _ , . Critical Age
y,v.. E-modulus Strength - Cohesion .. ' °
fiber surface length resistance
Steel +
Asbestos +
Carbon +
Glass +
Organic fibers —
NOTE: + = positive reinforcement.
— = negative reinforcement.
Steel fibers have been used in the production of cement pipe.^** The
use of steel fibers is certainly more convenient than the use of traditional
steel reinforcement. They are, however, more expensive per ton of
reinforcement than conventional steel reinforcement. The result of using
steel fibers is not readily predictable. An exact knowledge of the amount of
reinforcement imparted by randomly oriented fibers is not known. Steel fibers
also have a drawback in that unless a sufficient cover of cement is present
they will be susceptible to corrosion, thus weakening the pipe wall.
Product composition—Steel fibers are not currently used in the
commercial production of an A/C pipe substitute.
Uses and applications—Steel fibers are not currently commercially used
as a replacement for asbestos in a pipe product.
Manufacturing summary—Steel fibers are not used in a commercial pipe
product.
Glass Fibers—
Special qualities—The glass fiber reinforcement reduces the weight of
material in a product and therefore the energy requirement associated with
that weight. The energy needed for glass fiber production is roughly one half
that of steel per half metric ton; thus the total energy consumption per foot
^Although steel fibers have been used in producing conventional cement pipe,
it should be noted that this does not necessarily mean that they are auto-
matically suitable in A/C pipe; there are significant processing differences
between the two products.
**Source is an unpublished OSHA document on asbestos.
124
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of pipe is lower than that required for most other pipes.H* in addition
glass fiber does not rust and is generally compatible with cement provided it
can be made resistant to alkali attack. It is a fine, continuous, flexible,
uniform filament which makes it relatively easy to handle with automatic
equipment .^
CertainTeed products, an asbestos cement pipe producer, reports that
alkali resistant glass has only about 60 percent of the tensile strength of
asbestos. This company's experience is that glass reinforcing strength is not
retained over long periods of time, and some glass fiber is believed to
disintegrate during autoclaving. ^ In addition, glass is currently more
expensive than asbestos and compatibility with the A/C pipe manufacturing
process must be dealt with.^
Product composition—Conventional "E" glass fiber, commonly used in
reinforced plastics, is severely degraded by highly alkaline cement. However,
an alkaline-resistant glass fiber has been developed by Building- Research
Establishment, Gaston, England. The fiber is marketed by Pilkington Brothers
Ltd., of St. Helens, England under the name Cem-FIL. Cem-FIL Corp. of
Nashville, Tennessee, is the licensed American manufacturer of Cem-FIL fiber
products. The fiber is a high-zirconia, alkali-resistant glass fiber which
can be used with the highly alkaline cement commonly used for pipe
construction. (See "Glass Reinforced Concrete Pipe" in Pipe Substitute
subsection).
Uses and applications—See "Glass Reinforced Concrete Pipe" in Pipe
Substitute subsection.
Manufacturing Summary—See "Glass Reinforced Concrete Pipe" in Pipe
Substitute subsection.
Other Fibers—
Special qualities—Other fibers which have been examined for use in
cement and concrete composites include alumina, plastic, and carbon. Fibers
such as nylon, rayon, rockwool, mineral, cotton, acrylic, polyester,
Kevlar™, and other organic fibers have been studied, but not seriously
considered, due either to high cost, low effectiveness, or inadequate
resistance to the alkaline cement environment in Portland cement.**
*However, asbestos may not be in the class with "most other pipes" as it is a
natural product and not energy intensive.^-
**Source is unpublished OSHA document on asbestos.
125
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Product Substitutes—
A/C pipe is used primarily in the water and sewer main (including
laterals) areas. Water main substitutes for A/C pipe are ductile iron,
fiberglass reinforced plastic pipe, PVC, and reinforced concrete. Sewer main
substitutes for A/C pipe are vitrified clay, concrete, plastic, and ductile
iron.
In the more minor areas of conduits, drainage and irrigation pipe, these
various types of pipe are also competitive. There is no readily available
information on these areas. Less emphasis will be placed on these categories
since what applies to water and sewer lines could easily be extended to
include these areas.
Concrete Pipe—
Special qualities—Concrete pipe, reinforced and nonreinforced, has
qualities which are similar to those of A/C pipe, with steel replacing
asbestos as a reinforcing agent. Concrete is a durable, natural material with
excellent longevity. It is amenable to specialty uses with only minor
adjustments. This pipe is not used for pressure applications with the
exception of low pressure agricultural uses.
Product composition—Concrete is an aggregate of sand, gravel, and
cement. Concrete pipe may be produced without reinforcement, which is common
in the smaller sizes. Reinforced pipe consists of concrete reinforced,
circumferentially, with steel bars and/or one or more layers of welded wire
mesh.
Uses and applications—Concrete pipe, reinforced and nonreinforced is
used for water mains, storm and sanitary sewer mains, irrigation and
subdrains. In 1974, concrete pipe accounted for only 1.6 percent of the
nation's water mains; however, over 95 percent of this pipe was over 13 inches
in diameter." (See Tables 25 and 26). Concrete is used more often as sewer
mains, as shown by over 16 percent of the nation's sewers being concrete in
1974. The largest portion is over 24 inches in size (see Tables 27 and 28).^
Advantages/limitations—A primary advantage of concrete sewer pipe is its
availability, since it is often made out of local materials. This type of
pipe has excellent longevity, exceeding 50 to 100 years.^ Also, at sizes
greater than 24 inches, it costs less than A/C pipe. For deep, buried uses
this equals properly specified A/C pipe for strength.*-
Reinforced concrete pipe may also be cast in elliptical or arch
shapes. ^ These shapes allow for the same cross-sectional area with a
smaller effective height, thus it may be buried in shallower trenches compared
to circular pipes. This can contribute to lower installation costs. These
shapes also give a design advantage since their hydraulic properties differ
from those of circular pipes. This is important since sufficient velocity
must be maintained to prevent the settling out of suspended solids from
sewerage, and to prevent excess velocities which could lead to increased
126
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abrasion of pipe surfaces. Control of the flowing fluids occurs as a result
of the changing cross-sect.ional areas.*
Concrete pipe is also versatile in that it may be designed for a
particular use. ^ When stronger pipe is necessary, more steel reinforcement
may be added and/or the wall thickness increased. Aggressive fluid or soil
conditions may be counteracted with thicker walls or by adjusting the chemical
composition of the concrete.**
The primary limitation of all concrete/cement pipes, including A/C, is
that they are susceptible to attack by acids. ^ Industrial wastes may
contain aggressive substances. High sulfate soils, when they become moist may
release sulfates which can attack the pipe. Septic conditions in a sewer pipe
can lead to hydrogen sulfide formation, which also reacts with water to form
acid, and attacks the inner wall of the pipe. Hydrogen sulfide formation is
of particular concern in the warmer southern sectors of the country.
Product manufacturing summary—Non-reinforcing sewer pipe is found in
diameters ranging from 6 inches to 26 inches. Reinforced concrete sewer pipe
is generally available in sizes from 12 inches to 144 inches, and it is not
uncommon to use reinforced concrete for mains in excess of 20 feet in
diameter. ^ Pipe length is determined by the standards, uses, and weight of
the pipe. The handling of the pipe is a particular design consideration for
unreinforced pipe, since the pipe must be strong enough to withstand
handling. Six to eight inch diameter pipe is common in 4 feet to 6 feet
lengths. The standard length for reinforced pipe is about 8 feet, although
pipe may be custom produced in lengths exceeding 20 feet.
There are approximately 375 manufacturers of concrete pipe in 47
states. *••* Production volume information is published by the American
Concrete Pipe Association.1
Vitrified Clay Pipe (V/C) —
Special qualities—V/C pipe's primary qualities which make it attractive
as a replacement pipe include the fact that it is constructed from inert
materials (clay). However, its cost is greater than A/C, concrete, or PVC
pipe.1
*It should be noted that, although such casting of shapes is useful, they
represent only a very small portion of the total pipe market.1
**Asbestos is also versatile - three classes of A/C distribution pipe are
produced and nine classes of A/C transmission pipe.1
127
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Product composition—V/C pipe is manufactured from shales and clay which
are inert materials. °Hydrous aluminum silicates are the clays most
suitable for the manufacture of V/C. They have the plasticity essential for
the extrusion process, they are stable at high temperatures and have good
drying and firing properties.
Uses and applications—Vitrified clay pipe (V/C) is used primarily in
non-pressure applications such as sanitary and storm sewers, septic tank
drainage fields, and underground collection systems. ? Over two-thirds'
of all sewer mains currently in the ground are V/C pipe.* The majority of the
pipe is in the 8 to 14 inch range, while only 3 percent is reported to be over
24 inches in diameter (see Tables 27 and 28).
Advantages and limitations—Among V/C pipe's qualities is the fact that
it is one of man's oldest known pipe materials. ^° > *•' Clay has a proven
record of performance, it has been used for centuries. Clay has been used in
the United States since 1815.^^ Vitrified clay is an inert material and
thus unaffected by most normal components in domestic and industrial
sewerage.^ it also has a long life expectancy, good flow characteristics,
and abrasion-resistance. In addition, V/C pipe is produced with domestic
materials.
The main limitation of V/C is weight, as it is extremely heavy. It also
is a rigid pipe and thus needs extra care in handling and bed preparation.
Its lack of flexibility could be a limiting factor, particularly in high
stress situations. It also is only manufactured in short lengths which
results in the use of more joints per mile of pipe.
Product manufacturing summary—V/C pipe is produced from clays and shales
(see Product Composition). The mined clay is mixed and ground to obtain the
proper mixture and consistency.-''" The clay pipe is extruded, finished and
air dried. This green pipe is vitrified by heating in a kiln at approximately
2000°F (1100°C). Finished pipe is then tested according to ASTM procedures.
V/C pipe is commonly found with nominal diameters from 3 to 42
inches. ° The length varies, but 6 to 7 feet is common, with some of the
smaller sizes available in lengths up to 10 feet. ^
Name and location of manufacturers—A list of V/C manufacturers who are
members of the National Clay Pipe Institute was provided by the National Clay
Pipe Institute ' and is included below. These companies may operate several
plants.
9 Can-Tex Industries
Division of Harsco Corporation
P. 0. Box 340
Minerals Wells, TX 76067
*However, less than 50 percent of sewer pipe currently being installed is
vitrified clay.
128
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• Clow Corporation
Clay Products Division
300 S. Gary Avenue
Carol Stream, IL 60187
• Denver Brick and Pipe Company
P. 0. Box 2329
Denver, CO 80201
• W. S. Dickey Company
P. 0. Box 6
Pittsburg, KS 66762
• The Logan Clay Products Company
P. 0. Box 698
Logan, OH 43138
• Mission Clay Products Corporation
P. 0. Box 391
Whittier, CA 90608
• Pacific Clay Products, Inc.
9500 S. Norwalk Boulevard
Sante Fe Springs / CA 90670
• Pomona Pipe Products Company
P. 0. Box 20400
Greensboro, NC 27420
• Superior Clay Corporation
Uhrichsville, OH 44683
Production volumes—Pipe production figures in terms of kilometers of
pipe and size distribution could not be located. Yearly production figures
reported by the Department of Commerce in its publication Construction
Review,18 are included in Table 30.
TABLE 30. VITRIFIED CLAY SEWER
PIPE PRODUCTION
FIGURES 1973-197818
(thousand metric tons)
Year
1973
1974
1975
1976
1977
1978
Production
1,578
1,355
1,126
1,006
970
921
Shipments
1,494
1,319
1,080
996
1,004
855
129
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Plastic Pipe—
Special qualities—This section on plastic* emphasizes polyvinyl chloride
(I'VC) although the properties of all plastic pipe are fairly similar. Table
31 is a list of the physical properties of the major thermoplastics. PVC is
inert to inorganics such as acids, alkalis, and salts. Plastic is not subject
to electrochemical or galvanic action. Ultraviolet radiation can effect the
polymer bonds, but is not a concern in pipe which is not exposed to direct
sunlight. Table 32 is a listing of the chemical resistance of plastic pipe to
various chemicals.
Plastics are viscoelastic, that is, they respond to stress as if they
were a combination of elastic solids and very viscous fluids. Consequently,
they have elasticity, strength and form stability, as well as flow and
sensitivity to time under load, rate of loading, and temperature. The viscous
component tends to dampen the response between stress and strain. As a
result, material cracking or failure versus creep or excessive deformation,
usually becomes the controlling performance criteria for plastics under long
term stress. This must be accounted for in the safe design of pipe subjected
to continuous loading, such as pressure pipe.
Smooth walled thermoplastic pipes behave as hydraulically smooth pipes.
The flow characteristics do not deteriorate with time since plastic is
noncorrosive.
Product composition—There are literally thousands of plastic materials.
These polymers are formed from reactions with many of the carbon chain
molecules found in petroleum products or synthesized in the laboratory.
Polyvinyl chloride is formed from the reaction of vinyl chloride monomers, to
form the PVC polymer.
Uses and applications—Many types of plastic have been created by polymer
chemists, which may be formed into pipes. These include polyvinyl chloride
(PVC), polyethylene (PE), acrylonitrile-butadiene-styrene (ABS), and
polybutylene (PB), which have a range of characteristics and properties as
great if not greater than any other category of traditional piping material.
Plastic piping has a broad range of applications including^ ,20,21.
hot and cold water supply; drain, waste and vent lines; abrasive slurry lines;
gas distribution; water mains and services; well casings; communications and
power ducts; and vacuum lines. Rural water distribution and private sewerage
systems are almost exclusive applications of plastic piping. Well over half
the piping used for gas transmission and telephone conduits is plastic.
*Note: Except where otherwise referenced, the material in this section was
obtained from: "Thermoplastic Piping, A Report by the ASCE Task
Committee on Plastic Pipe." Stanley A. Mruk, Technical Director, PPI.
(ASCE Annual Convention, San Francisco, October 17-21, 1977.) 52 p.
130
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TABLE 31. TYPICAL PHYSICAL PROPERTIES OF MAJOR THERMOPLASTIC PIPING MATERIALS
19
Property @ 75-F
ASTM
test
ABS
PVC
PE
CPVC
PB
PP
SR
Specific Gravity D-792 1.04 1.08 1.40 1.36 1.54 0.92 0.94 0.95 0.92 0.92 1.06
Tensile Strength PSI (103) D-638 4.5 7.0 8.0 7.0 8.0 2.0 2.4 3.2 4.2 3.5 3.8
Tensile Modulus PSI (105) D-638 3.0 3.4 4.1 3.6 4.2 0.90 1.20 1.2 0.55 1.1 3.2
Strength, isod
ft-lbs/inch notch
r— tt —
3'2
Specific Heat Btu/lb - °F — 0.32 0.34 0.25 0.23 0.20 0.50 0.54 0,55 0.45 0.45 0.33
Approx. Operating Limit
°F, non-pressure
F, pressure
180 180 150 130 210 100 130 160 210 200 140
160 160 130 110 180 90 120 140 180 150 -
*Exact operating limit may vary for each particular commercial plastic material. Effects
of environment should also be considered.
Key: ABS - Acrylonitrile-butadiene-styrene
PVC - Polyvinyl chloride
CPVC - Chlorinated polyvinyl chloride
PE - Polyethylene
PB - Polybutylene
PP - Propylene Plastic (polypropylene)
SR - Styrene Rubber
-------
TABLE 32. CHEMICAL RESISTANCE GUIDE AT AMBIENT TEMPERATURES
19
Compounds
ASS
PVC
I II
CPVC PE PB PP SR CAB POP
Chlorinated
polyether
Fluorocarbon
TFE/FEP PVF
Inorganic
Acids, dilute G G L
Acids, cone. 80% L L L
Alkalies, dilute G G G
Alkalies, cone. 80% L G L
Gases, Acid (HC1 & HF) Dry L L L
Cases, Acid (HC1 & HF) Wet L C- L
Gases, Ammonia, Dry L G L
Gases, Halogens, Dry L L L
Gases, Sulphur gases, Dry P G L
Mineral Oil G G G
Salts, Acidic G G G
Salts, Basic G G G
Salts, Neutral G G G
Salts, Oxidizing L L L
Organic
C
G
G
C
L
G
G
L
/•*
\J
C
G
G
G
L
C
L
G
G
G
G
G
L
G
I,
L
C
C
C
C
L
G
G
G
G
G
L
L
G
G
G
C
G
G
L
C
G
G
G
G
P
P
G
C
G
G
G
G
P
G
L
L
L
L
L
P
L
L
G
G
L
L
P
L
p
P
P
P
P
P
G
G
G
G
G
L
G
l,
L
C
L
L
L
G
G
G
G
L
G
G
G
G
G
G
G
L
G
G
G
G
G
G
G
G
G
G
G
G
G
L
G
G
G
G
G
G
G
G
G
G
L
L
G
L
G
G
G
G
G
L
Acids
Acid anhydrides
Alcohols, glycols
Estors, Ethers, Ketones
Hydrocarbons, Alphalic
Hydrocarbons, Aromatic
Hydrocarbons, Halogenated
Natural Gas, (fuel)
SyntnGtic Gss (Fuel)
Oils, Animal & Vegetable
G
L
L
P
L
L
G
G
G
L
G
P
L
L
G
G
G
I,
L
P
L
L
G
G
L
P
G
P
G
L
G
G
G
L
L
L
L
P
G
L
G
L
G
L
L
P
G
G
G
L
C
L
L
P
G
G
L
L
P
?
P
P
p
L
L
P
P
P
P
P
G
G
G
L
L
L
L
P
G
G
L
L
G
L
L
L
G
G
G
G
G
L
G
G
L
G
G
G
L
L
L
L
L
L
L
G
G
G
*Exact chemical resistance depends upon particular commercial grade of plastic, specific chemical
compound and conditions of exposure. Consult piping manufacturers for more detailed listings.
G = Good resistance (Recommended for most cases)
L = Limited resistance (Has many uses; tests recommended)
P = Poor to No resistance (Not recommended for most cases)
Key: AES - Acrylonitrile-butadiene-styrene
PVC - Polyvlnyl chloride
CPVC - Chlorinated polyvinyl chloride
PE - Polyethylene
PB - Polybutylene
PP - Propylene Plastic (polypropylene)
SR - St.yrene Rubber
CAB - Cellulose acetate-butyrate
POP - Polyethylene oxide
-------
An American City and County Magazine survey (1974) estimated PVC pipe is
used for almost 7,000 miles (11,265 km) of water main,° of which 62 percent
was under 6 in. (15 cm) in diameter. The same study for sewer mains' showed
2 percent or over 9,000 miles (14,485 km) of sewer mains were plastic pipe, of
which 82 percent was in the 8 to 14 inch size range. In a 1981 study by the
same source, it was noted that growth of plastic pipe did not measure up to
the 1974 projections. Even though plastic pipe accounted for nearly 6 percent
more installed miles in 1980 as compared to 1974, it was reported as only one
percent more of in-place pipe mileage - not a significant gain.^
Advantages/Iimitations—PVC and other plastic pipe materials have many
properties which make them suitable, or superior, for use in a wide range of
applications. Considered beside traditional piping material, thermoplastics
are less rigid and less strong, their maximum service temperatures are lower
and their thermal coefficients of expansion are higher. However, they do not
corrode, are biologically inert, and resist chemical attack. They are
sufficiently strong and their temperature limits.are quite adequate for most
applications.*•"
Traditional pipes have stiffness values which are an order of magnitude
greater than those of plastics. Plastic pipes, being flexible, have unique
design considerations. Their flexibility is an asset because the maximum
deflection to preclude pipe failure is not as stringent a constraint as it is
with other pipe materials. PVC has demonstrated its ability to retain its
serviceability of deflections greater than 5 percent, the limit often imposed
on traditional pipes. "
Because of its high strength and light weight, PVC pipe may be produced
in lengths much longer than its traditional counterparts. This means
installation is easier since fewer joints are needed. Sizes under 4 inches in
diameter are available in 20 foot lengths, while 6 inches and up are available
in 10 foot lengths. PVC ranges in size from very small (1/2-inch or less) to
15 inches in diameter. Recently (1978), some manufacturers have made sewer
pipe available in the 18 to 27 inch range.2*
A limitation of plastic piping materials is that cyclic loading, which
often results from water hammer or pump vibration, can cause plastics to
fail. The maximum stress, temperature, and frequency are all determining
factors. The amplitude of the stress is often the primary
9071
determinant.•i(J'z Such stress causes fluctuations in the pipe diameter
which leads to fatigue and ultimately, failure.
These limitations are easily overcome by proper design. Normal practice
is to choose a pipe whose rated working pressure is not exceeded by the static
plus surge pressure. For example, a 200 psi (1380 KN/m2) pipe is chosen
when 160 psi (1100 KN/m2) is required. AWWA C-900 standards include a built
in surge pressure allowance.
Product manufacturing summary—PVC pipe is a thermoplastic as opposed to
thermosetting material. As its name (thermoplastic) implies, the material
133
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softens when heated and hardens upon cooling. Thermoplastic pipe is
manufactured by the extrusion process. There are numerous manufacturers of
plastic pipe. Among the largest manufacturers of plastic pipe for water and
sewer use (a direct competitor to A/C pipe) is Johns-Manville Corporation.
Production volumes—PVC accounted for 72 percent or 850 million kilograms
of the total 1,170 million kilograms of pipe material manufactured in 1978.
PVC also accounted for 86 percent of the plastic pressure pipe shipped in
1978.22
PVC pipe is not as new a product as is commonly thought. By 1948 a small
thermoplastic piping industry in the U.S. produced about 450,000 kg of
product. Phenomenal growth followed and the almost one billion kilograms
produced in 1976 is estimated to have accounted for almost 25 percent of the
footage of all types of piping. Most of this footage is in the small diameter
pipes. Some estimates of PVC pipe in use in 1980 are given as 57,000 miles
(91,735 km) of sewer pipe and 1.3 million miles (2.1 million km) of water
pipe.21
Production Figures for the last few years are given in Tables 33 and 34.
Glass Fiber Reinforced Concrete Pipe—
Special qualities—ARC Concrete, a subsidiary of Amy Roadstone Corp.
Ltd., produces a glass fiber reinforced concrete pipe of special construction
which they market (in the United Kingdom) under the designation ARC Slimline
Glass Reinforced Concrete Pipe.11>23-25
TABLE 33. TOTAL PLASTIC PIPE AND FITTINGS PRODUCTION VOLUME
ESTIMATES 1960-1978 (millions of kilograms)*22
Year
1960
1961
1962
1963
1964
1965
1966
1967-
1968
Pipe
Production
27.2
40.0
50.6
59.7
75.7
91.8
124.4
140.3
193.2
Year
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
Pipe
Production
237.7
318.0
445.4
611.4
792.4
800.0
668.1
891.6
Committee estimate -
Committee estimate -
1163.1
1253.0
Committee estimates total pipe and fittings poundage.
134
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TABLE 34. ESTIMATED PRODUCTION VOLUMES FOR VARIOUS TYPES OF PIPE - 1974-197822
Pipe, cube &
conduit by
material
PVC
ABS
PE (non-
corrugated
PE (corrugated)
SR
CPVC
Total
1974
(est.)
540
60
55
70
20
2.5
747.5
1975
(est.)
MILLIONS
475
65
40
55
9
3
647
1976
(est.)
OF KILOGRAMS
595
85
60
85
2
4
831
1976
(est.)
770
100
75
95
0.7
5
1045.7
1978
Reported
800
80
70
*
*
4
954
(est.)
845
85
75
155
*
4.3
1164.3
Key: PVS = Polyvinyl chloride
ABS = Acrylonitrile-butadiene-styrene
PE = Polyethylene
SR = Styrene Rubber
CPVC = Chlorinated polyvinyl chloride
*Actual production unknown; total number at bottom reflects original author's
estimates for these figures.
-CONTINUOUS FILAMENT GLASS
FIBER REINFORCED
FINE CONCRETE
LINING LAYER
Figure 1. Section through a slim line pipe.11'21*
135
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In the development of this concrete product one of the first observations
was that the fiber appears to act as a crack arrester rather than
reinforcement in the normal sense. ^ When the fiber is placed near the
surface of concrete products it arrests cracks by evening out high stress
concentrations, thus raising overall stress tolerance.
This is a significant property difference in the behavior of glass
reinforced concrete as opposed to glass reinforced cement. In glass
reinforced cement the dominant failure mechanism is that of bond slippage
rather than fiber failure, preventing the full use of the high fiber tensile
strength.11
Product composition — The ARC product consists of a centrifugally spun,
high strength concrete core, with integrally cast, alkali-resistant glass
fiber reinforcement adjacent to the inner and outer surfaces, and an internal
unreinforced lining of fine aggregate concrete (Figure 1).
Uses and applications — ARC Slimline Glass Reinforced Concrete Pipe is
suitable for use in conveying sewerage or surface water under gravity at
atmospheric pressure.11 The pipes are considered equivalent to
conventionally reinforced concrete pipes in terms of strength, hydraulic flow
characteristics and durability. Slimline pipes should have .a service life
equivalent to conventional spun concrete.
Advantages/ limitations — Glass reinforced concrete (GRC) combines several
of the advantages of concrete and steel reinforced pipe. The properties of
concrete (good compression strength and corrosion resistance) allow it to be
combined with the fiber to produce a product suitable for use in non-pressure
applications.
Because of the nature of GRC, savings can be achieved in areas of
material and energy. A strong pipe can be produced which is thinner and
lighter than conventional concrete pipe which makes for easier handling.
The slim form of the pipe enables it to be handled and laid in trenches
of lower widths than normal. This can show a significant reduction in the
amount of excavation and bedding materials necessary, thus lowering
installation costs (see Table
Product manufacturing summary — The pipe is centrifugally molded as are
most cement pipes. Glass fiber is continuously injected onto the mold where
it is helically wound onto the mold surface. 22,23 cement is added. The
body concrete is then added, vibrated, and centrifugally dewatered. The
internal GRC is then injected. A final coating of fine concrete is then
applied. The pipes are steam cured and allowed to mature at least 4 weeks
before delivery. Quality control includes checks on raw materials, visual
dimension checks and hydraulic and crushing load tests. The pipes may be made
with ordinary Portland cement or sulphate resisting cement, depending upon
soil conditions. 24-
136
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TABLE 35. GRC PIPE FORMS24
Internal
diameter
(mm)
600
675
750
825
900
975
1050
1125
1200
Outside
diameter
(mm)
700
788
880
963
1050
1138
1225
1313
1400
Name and location
Effective
length
(m)
2.44
2.44
2.44
2.44
2.44
2.44
2.44
2.44
2.44
Wall
thickness
(mm)
50.0
56.5
65.0
69.0
75.0
81.5
87.5
94.0
100.0
Approx.
weight
pipe
(kg)
620
864
1010
1178
1395
1642
1900
2187
2480
of manufacturers — There are no
Traditional
recommended
overall
trench
width
(m)
1.35
1.45
1.50
1.60
1.90
2.00
2.05
2.19
2.30
Slimline
recommended
overall
trench
width
(m)
1.00
1.09
1.18
1.27
1.35
1.44
1.53
1.62
1.70
domestic manufacturers
currently producing a glass fiber reinforced cement pipe. Cem-FIL Corp., of
Nashville, Tennessee, is the domestic representative of ARC concrete.2" but
they are not currently producing glass-fiber reinforced cement pipe.
Production volumes—No GRC pipe has been produced domestically but as of
1979 over 13 km is reported in use in Europe. -*
Cast and Ductile Iron Pipe—
Special qualities—Ductile iron results from the addition of magnesium to
the molten iron, which causes a change in the internal grain structure of the
iron. The carbon in ductile iron is in the form of nodules rather than the
flakes prevalent in gray cast iron. As a result stresses are more easily
dispersed. The resulting product is stronger and more ductile than gray cast
iron.
Table 36 is a summary of some of the properties of ductile iron.
TABLE 36. PROPERTIES OF DUCTILE IRON PIPE27'28
Property
(psi)
Tensile strength 60,000
Yield strength 42,000
Elongation 10%
Elasticity modulus 24,000,000
137
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Product composition — Ductile iron is a ferrous product consisting
primarily of iron. Magnesium is added to enhance a change in the carbon in
the internal grain structure as explained above. Other materials may be added
to adjust the chemistry of the resulting steel.
Uses and applications — Iron pipe is used primarily for the transmission
of gas, water, and sewerage. The first recorded use of cast iron pipe was in
Germany in 1455. Between 1664 and 1688 the French laid cast iron pipe to
supply water to Versailles; this pipe is still in use today. Cast iron pipe
was first introduced in the United States in Philadelphia in 1804.^7
A process for commercial production of ductile iron was developed in
1948. Ductile iron was first used for the commercial production of pipe about
1955. 27,29 xoday ductile iron pipe has virtually replaced gray cast iron
pipe in the market. 27,29 Much gray cast iron pipe is now in place but
essentially all new iron pipe being installed is ductile iron
Iron pipe production is expressed in two categories: pressure and
soil.1" Pressure pipe is the pipe commonly used for water distribution and
transmission, gas distribution and transmission, and sewer force mains. ^°
Soil pipe is used primarily indoors or as laterials (non-pressure). These
uses might include bathroom plumbing mains or the connection to the sewer
main. In 1975 it was reported that cast iron pipe accounted for 75 percent of
the nation's water mains, primarily in the 6 to 12 inch range (Tables 25 and
26).° Cast iron is not popular for sewer mains - only 3 percent of the
nation's mains were reported to be iron.^ However, cast iron was used
almost exclusively as sewer laterals until the introduction of plastic pipe.
Advantages/ limitations — Ductile iron pipe's high tensile strength allows
the use of diameter to thickness ratios in which the deflection of the pipe,
under trench loads, is of sufficient magnitude that the principles of flexible
pipe design are applicable. Ductile iron pipe can handle excessive stresses
due to water hammer, highway traffic, etc., and service repair is
infrequent. 1.27,28,32,33 Ductile iron pipe also has high machineability to
facilitate and expedite installation and appurtenance installation.-^
There are some limitations to the use of iron pipe. Its ability to
corrode is often mentioned as a limitation; its proven track record disputes
any major objections due to added coating materials. Iron corrodes under
severe service conditions like aggressive soils (found in less than 5 percent
of the nation) or saltwater. 28 proper internal linings and external
protection (including plastic wrap) can offset most corrosive conditions. 2°
Iron pipe is almost always lined with cement mortar to prevent internal
corrosion and to improve flow characteristics. Plastics such as polyethylene
are used as encasements when necessary to prevent external corrosion due to
aggressive soils or electrolysis. Specialized cases may be treated with
coatings like asphalt, coal tars, or glass liners. 27, 33
138
-------
Iron is also susceptible to electrolytic action. The joining of another
metal line, like copper, aluminum, or galvanized steel, will induce galvanic
reactions although proper design considerations can minimize any adverse
effects on the pipe. Cathodic monitoring stations may be required for ductile
iron pipe installations, depending on local soils conditions.^
Product manufacturing summary—Ductile iron pipe is produced primarily
from natural, domestic resources. The iron is mainly scrap and the coke is
produced from domestic coal. Ductile iron pipe is cast centrifugally in 18 to
20 foot laying lengths using the deLavaud-' process. Molds are lined with a
mixture of thermosetting plastic and sand. Molten iron flows from a cupola to
ladles to electric induction furnaces where the chemistry and temperature is
adjusted. The quantity of molten metal introduced to the rotating mold
controls the pipe thickness. The force generated by rotation holds the metal
to the walls of the mold and forces lighter impurities to the inside surface
of the pipe from which they can be cleaned. After the iron solidifies, the
pipe is removed, annealed in ovens, cleaned, lined, and tested.
Pipe is cast from 3 to 54 inches in diameter in 18 to 20 foot lengths.
The wall thickness is dependent upon the use and ranges from 0.25 inches for 3
inch diameter pipe to over 1 inch for 54 inch diameter pipe.
Asbestos industry sources^ maintain that cast iron in pressure pipe
consumes approximately eight times more total energy in manufacture than A/C
pipe, with cast iron in sewer pipe consuming ten times the energy.
List of manufacturers—The primary manufacturers of ductile iron pipe are
also members of the Ductile Iron Pipe Research Association. They include:
• American Cast Iron Pipe Company
Birmingham, AL
• Atlantic States Cast Iron Pipe Company
Phillipsburg, NJ
• Clow Corporation
Oakbrook, IL
• McWane Cast Iron Pipe Company
Birmingham, AL
• Pacific States Cast Iron Pipe Company
Provo, UT
• U.S. Pipe and Foundry
Birmingham, AL
Production volumes—Construction Review^-", a Department of Commerce
publication, compiles monthly and yearly production figures for cast (ductile)
iron pipe. They are given in Table 37.
139
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TABLE 37. PRODUCTION VOLUMES FOR CAST
IRON PIPE AND FITTINGS 1973-
197818 (thousands of metric tons)
Year Pressure Soil
1973 1900 865
1974 1775 700
1975 1140 540
1976 1210 600
1977 1455 620
1978 1545 665
COST COMPARISON
Fiber Substitutes*
The most promising route for achieving the objective of a universal
replacement for asbestos-cement is the development of glass-reinforced cement
technology. With the increasing concern over the rising price of steel for
reinforcement and the relatively high energy consumption for its
manufacture, 1 glass fibers promise to offer an attractive alternative to
both steel and asbestos as cement reinforcement.
During Farahar's studies,*-*- which began in 1971, it was noted that
although glass fiber was (at that time) more than six times more expensive per
ton (compared to steel), it was theoretically capable of providing more than
three times the usable tensile strength and its lower specific gravity, at
2.5, suggested that the cost per unit of tensile strength from glass fiber
could be less than 2/3 that of steel. ^
"E" glass fibers could be used with alumina cement to prevent the
alkaline attack of regular Portland cement, but the high cost of materials
(glass and cement) prohibits all but specialized use. The high-zirconia
alkali-resistant glass fiber marketed by Cem-FIL Corp. or a similar product
(e.g., a low-zirconia alkali-resistant glass fiber recently patented by
*It should be noted that it is the opinion of the AIA that current technology
does not provide a fiber resistant to a cementitous environment, the A/C pipe
manufacturing process, or its curing cycle.*•
140
-------
Johns-Manville Corporation)34 seem to be the most likely candidates for
glass fiber substitute development, although continued testing now indicates
that products may lose strength with time and cannot be used for external or
load-bearing applications.
Product Substitutes
Table 38 shows some of the substitute products for A/C pipe may be
economically competitive at initial cost comparisons. Other costs which
should be determined include: excavation, foundation requirements,
maintenance and installation costs including labor, and replacement schedule.
Pipe prices are known to fluctuate widely depending upon proximity to
manu-facturing sites and market conditions .-*•
The rising cost of energy is playing an increasingly important part in
the design and operation of municipal services (water and sewerage
treatment). Ductile iron pipe can show significant savings not only in repair
and replacement costs, but in the energy costs for pumping as well.-^9
Pipe sizing may also affect cost. Pipe sizes are given in terms of a
nominal diameter. However, the internal diameter of a pipe is not the same as
its nominal diameter. For instance, for a nominal diameter of 8 inches the
corresponding internal diameters for various types of pipe are: Ductile iron
- 8.39", A/C pipe - 7.85", PVC pipe - 8.044".3^ This shows ductile iron
pipe to have a larger internal diameter than that of the other pipes, for the
same nominal size. Thus, savings can be accrued since less energy is needed
to pump water through an iron pipe, as opposed to pumping an equivalent volume
of water through a non-iron pipe.
Other ferrous products including steel pipe can be viable substitutes for
asbestos in specialty applications. Steel pipe is generally not used in water
or sewer mains, but is employed in such uses as 40-foot diameter penstocks for
dams and power plants. Steel pipe is considerably more expensive than A/C
pipe but can be used as a very acceptable substitute. ^
CURRENT TRENDS
Current trends in the pipe industry as a whole are difficult to judge.
The demand for pipe is a function of new installations and replacement
schedules. Current economic situations have led to a decrease in new housing
starts and tightening financial situations in the nation's cities may lead to
a decline in the rate of pipe replacement. The reduction in use of one type
of pipe may be offset by an increase in another pipe type.
For instance, the production of V/C pipe appears to be decreasing. This
may be attributed to several factors. The amount of all types of pipe may be
reduced as the installation of new sewers is completed. Henceforth, the
majority of new pipe would be needed only for replacement and maintenance.
V/C pipes' share of the market may also be assumed by another type of pipe,
probably plastic.
141
-------
TABLE 38. PIPE PRICE ESTIMATES (Feb. 1980)
Approximate price per foot (meter)
Water
Material
Asbestos cement
8" (20 cm) 15
4.50 (15.00)f 13.
II
00
(16",
g
Ductile iron
Vitrified clayf
Reinforced concrete
Nonreinforced concrete
PVCJ
Fiberglass "reinforced
PVC1
6.00 (19.75) 14.
(16
-
-
10.
4.25 (14.00) 9.
(12
6.25 (20.50) 12.
(12
50
II
t
50
75
II
»
25
It
»
(38 cm) 24" (61 cm)
(43.30)^ _b
41 on)
(47.50) 24.50 (80.40)
41 cm)
-
15.508(51.00)*
(34.50)*
(32.00)
31cm)
(40.00)
31 cm)
8" (20
3.00 (9
6.00 (19
2.50 (8
-
2.25 (7
2.75k (9
-
cm)
.80)
.75)
.20)
.40)
.00)
15"
10.00-14.00
14.50
(16",
9.75
6.00
4.00
10.50
(18",
-
Sewer
(38 cm)
(32.80-46.00)
(47.
41 cm)
(32.
(19.
(13.
(3,4'
46 cm)d
-
50)
00)
75)
00)
50)
24"
20. 00-21. OOc
24.50
29.00d
11.50d>h
8.00d
16.00
(18",
(61 cm)
,dx (82. 00-98. 50)
(80.
(95.
(37.
(26.
(52.
46cm) d
-
50)
00)
75)
25)
50)
All prices rounded to nearest $.25.
J.M. Translte pipe - Coupling and rings with belled ends - 13' (4 meter) lengths. For vinyl coating add: ?.18/ft (0.60 meter)
for 8" and $.32/ft (1.05 meters) for 16" (41 cm) pipe.
J.M. Translte pipe - Coupling and rings with belled ends - 13' (4 meter) lengths.35
• May be used as drainage pipe also. (All sizes).
eAmerican Cast Iron Pipe - Ductile iron, cement liner, class 50, Pushon Fastite Coupling. 3(>
f T7
Bell & Spigot with rubber gasket, by the truckload.J/
fleets ASTM 7678, max price includes freight to furthest point. Suitable for sanitary sewers or pressure mains.38
Includes freight for furthest point.3**
Tlortar joint - length 4' (1.2 meters) for 8" (20 cm) and 6' (1.8 meters) for 15" (38 cm) and 24" (61 cm).30
-'j.M. - SDR-26 (160 psi) for use in low pressure areas (no fire hydrants). ASTM D1748, 20' (6 meters) lengths. Much thicker walls
are available.31
kJ.M. - SDR-35, ASTM D30334. 12.5 ft (3.8 meter) lengths - sewer pipe.31
J.M. - Permanstrain.
*These are not pressure pipes.
tA.l.A comments.
NOTE: This table presents 1980 data which were the best available at time of issue of this report; change in
market conditions to the current time period should be noted. In addition, prices may differ according
to specific pipe required. Costs presented here should only serve for very general comparison purposes.
-------
Plastic pipe growth in the rural market has reached a steady growth
plateau and dominates this market. With the issuance of AWWA C-900, PVC can
be expected to enter a high growth phase in the municipal market.21 The
plastic pipe industry expects to account for half of all pipe installed by
1985.22
The relatively high price and low availability of some products, such as
carbon fiber substitute or Kevlar^ pipe substitute, is largely a function
of the early development stage of these materials. As fiber substitutes
improve and become more available and cost effective, the evolution of a new
generation of asbestos-free pipes could occur. Changes in product demand are
likely to influence availability and/or the manufacturer's expected return
from the high capital expenditures associated with new product development,
hence cost.
Overall, trends can be summed up from review of a June 1981 article in
Americal City and County which focuses on a water main pipe survey (1981) and
is titled "Cost, not material, shifting pipe choice". Ductile iron is quoted
as being the predominant choice of pipe for water main use by 65 percent of
the respondants, while A/C pipe claimed 15 percent and plastic pipe, 11
percent. The South Central and Western States prove to be the bastions of A/C
pipe use, where there is a far greater proportion of A/C pipe in place than in
other regions and also a greater percentage of 1980 pipe installed was A/C,
although the preference did not run true in states such as Washington and
Oregon. The South also continues to use A/C pipe prolifically (A/C got its
start here in the postwar economy). It appears that, where A/C pipe is being
installed, it is being laid in greater quantities, in areas of the country
expanding their water systems. This accounts for the fact that 70 percent of
the replies nationwide indicated that they installed ductile iron pipe last
year, yet it made up only 38 percent of total mileage installed whereas A/C
pipe made up 40 percent of the mileage installed yet was only installed by 23
percent of the responding utilities. A/C pipe, according to South Central and
Western respondants, is chosen over ductile iron due to the fact that, in
smaller diameters, it is as much as 50 percent less expensive per foot. They
also noted that it was easier to tap than ductile iron, which was much more
competitive at larger diameters due to strength characteristics. A/C pipe was
suggested as the pipe to specify up to 12 inches, with ductile iron required
in the larger sizes. The South Central and Western respondants felt A/C pipe
was necessary due to soil electrolytic conditions there which tend to corrode
iron pipe.-*
In general, the trend is towards larger diameter pipe (14 inches or
greater) to replace hastily installed undersized mains. With labor costs
currently the major factor, pipe costs are a bit less important such that
larger diameters may be laid. In addition, the survey revealed that 1981
estimates indicate that, in this year, utilities will install only a little
more pipe than in 1980. Replacement, not expansion may be the case in many
areas (replacements accounted for approximately 21 percent of all pipe
installed in 1980-81).5
143
-------
Data breaking down use of pipe by region points to the Northeast as
putting in the smallest number of new pipe, with a large proportion as
replacement. They also reported the smallest percentage of plastic pipe in
place and installed the smallest percentage of it in 1980. The Southeast, by
contrast, reported the largest percentage of in-place and 1980 installed
plastic pipe, and showed the strongest preference for plastic. This region
has the largest percentage of new pipe. The North Central region reported the
highest proportion of cast or ductile iron in place and the smallest
proportion of A/C pipe both in-place and installed in 1980. North Central
prefers iron pipe over A/C and plastic. The South Central states put in more
A/C pipe and much less iron in 1980, and show the weakest preference for iron
and the strongest for reinforced concrete. The Great Plains fall between,
with only a small amount of pipe being installed, and that consisting of A/C
and plastic pipe. The West did not use much iron compared to the others and
more A/C and steel are found in the ground there. The West showed the
strongest preference for A/C pipe for 1981 construction.5
Overall, the survey reflected the influence of budgetary constraints on
U.S. water systems, and indicated that the predicted growth of plastic pipe
may still be yet to come.-'
CONCLUSION
The use of substitutes for asbestos cement pipe in new construction or
for replacement service is covered extensively in the trends section,
especially for water pipe uses. Available substitutes include:
• ductile iron
• concrete pipe
• glass reinforced concrete pipe
» plastic pipe
• vitrified clay pipe
For intermediate size range pipe diameters (6 to 24 inches), asbestos
cement pipe is most commonly used, although some regions prefer the use of
iron pipe when diameter exceeds 12 inches.5 Depending on the requirements
of each individual case, the alternatives listed offer strong competition,
especially outside of this range. For instance, plastic pipe, vitrified clay
pipe, and iron pipe are all applicable in the small pipe diameter range. For
diameters greater than 24 inches and heads higher than 200 feet, the
substitute pipes compare very favorably or are more economical than asbestos
cement pipe. In addition, glass reinforced pipe, though not currently
produced in the United States, might possibly find use as a direct substitute
for A/C pipe, even in the intermediate range pipe size. This might occur in
those cases where high strength, resistance to corrosion, and low price are
all simultaneously required.
144
-------
In addition to the diameter size range, cetain other properties show
themselves to be important in pipe selection for certain uses. Ductile iron
is more suited for situations involving shock loads, vibration, and ground
movement in general. For nonpressure applications, vitrified clay pipe is
less expensive. Another possible advantage of substitutes may be the small
number of asbestos cement pipe manufacturing facilities which lead to greater
transportation costs for this product than those for pipes manufactured near
to the point of use.
It should be noted that none of the alternative products can substitute
for asbestos in all of the uses that it has now become established in.
However, as a group, they can meet all of the technical requirements placed on
A/C pipe. As both the water and sewer pipe markets appear to be in a state of
flux in varying regions due to different preferences, soils, and the general
state of the economy, this area is probably one in which significant change
could occur in the future.
145
-------
REFERENCES
1. AIA Comments on the Draft Substitutes to Asbestos Report, Submitted to
GCA 10/22/81.
2. Michaels, L. and Chissick, s. S., eds. Asbestos; Volume 1, Properties,
Applications, and Hazards. John Wiley and Sons. New York, NY. 1979.
3. American Water Works Association. AWWA Standard for Asbestos-Cement
Transmission Pipe, 18 in. through 42 in. for Water and Other Liquids.
AWWA C402-77. January 30, 1977.
4. Clifton, R. A. Mineral Industry Survey, Asbestos Industry 1978. U.S.
Bureau of Mines, August 22, 1979, and Clifton, Preprint from the 1980
Bureau of Mines Minerals Yearbook, Asbestos, p. 4.
5. American City & County, 1981 Water Main Pipe Survey, "Cost, not material,
shifting pipe choice", June 1981, p. 41-44.
6. Survey of Water Main Pipe in U.S. Utilities Over 2,500 Population.
American City. Morgan-Grampian Pub. Co., Pittsfield, MA. August, 1975.
52 p.
7. Survey of Sewer Main Pipe in U.S. Utilities Over 2,500 Population.
American City. Morgan-Grampian Pub. Co., Pittsfield, MA. August, 1975.
33 p.
8. Telecon. Mrs. Loretta Ferguson, Johns-Manville Corp., Denver, CO, (303)
979-1000, with Nancy Krusell, GCA Corporation, GCA/Technology Division,
April 22, 1981.
1
9. Telecon. Sharon Jackson, CAPCO, Ragland, AL, (205) 472-2111, with Anne
Duffy/Nancy Krusell, GCA Corporation, GCA/Technology Division, 4/15/81
and 4/22/81, respectively.
10. Letter from Ed Mussler, GCA Corporation to Joe Jackson of Asbestos Cement
Pipe Producers Association. January 30, 1980. Notebook 3. Call 3.
11. Farahar, R. M. "Glass Reinforced Concrete." Publication of Unknown
Origin. Received from Cem-FIL Corp., Nashville, TN, in response to phone
call from Ed Mussler, GCA Corporation. GCA No. 7-03-007-0035. 6 p.
146
-------
12. CertainTeed Products' answers to question of John DeKany, U.S. EPA,
concerning Asbestos Rulemaking. Received at GCA on July 14, 1980.
13. Preuit, Russell. American Concrete Pipe Association, 703/821-1990.
Personal communication with Ed Mussler, GCA Corporation. February 11,
1980. Notebook 3. Call 17.
14. Simonds, R. A. and J. L. Warden. Water and Power Resources Service,
"Substitutes for Asbestos Cement Pipe" speech, at EPA/CPSC Substitutes
for Asbestos Conference, Arlington, VA. July 14-16, 1980.
15. American Concrete Pipe Association. American Concrete Pressure Pipe
Association. Membership Directory. Vienna, VA.
16. Clay Pipe Engineering Manual. National Clay Pipe Institute. Washington,
D.C. 1978.
17. Telecon. Sikora, Ed. National Clay Pipe Association, 815/459-3330, with
E. Mussler, GCA Corporation. February 11, 1980. Notebook 3. Call 20.
18. Construction Review. DOC. 25:9. September-October 1979. p. 48, 50, 52.
19. Mruk, Stanley A. "Thermoplastic Piping, A Report by the ASCE Task
Committee on Plastic Pipe." PPI. (ASCE Annual Convention, San
Francisco. October 17-21, 1977.) 52 p.
20. Telecon. Mruk, Stanley. Plastic Pipe Institute, 212/574-9400, with E.
Mussler, GCA Corporation. February 1, 1980. Notebook 3. Call 9.
21. Telecon. Walker, Robert. Uni-Bell Plastic Pipe Association,
214/243-3902, with E. Mussler, GCA Corporation. February 5, 1980.
Notebook 3. Call 16.
22. Statistics and Market Analysis Committee Report. PPI Annual Meeting.
The Plastic Pipe Institute. New York, NY. March 1979. 7 p.
23. The Agreement Board. ARC Slimline Glass Reinforced Concrete Pipes for
the Conveyance of Liquids under Gravity Flow (sic). Certificate No.
77/499. Garston, England. November 1977. 4 p.
24. Slimline Pipes. ARC Concrete. Company Brochure provided by Cem-FIL
Corporation. Nashville, TN.
25. The Specification and Performance of Slimline Glass Fiber Reinforced
Concrete Pipes. ARC Concrete. (Series presented at Technical Seminar
held at ARC Concrete Research Centre, St. Ives, (England) February 8,
1979).
26. Telecon. Caldwell, Phil. Cem-FIL Corporation, 615/883-7563, with Ed
Mussler, GCA Corporation. January 3, 1980. Notebook 3. Call 7.
147
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27. American Pipe Manual, 15 ed. American Cast Iron Pipe Company.
Birmingham, AL. 1979.
28. Telecon. Higgins, Mike. Ductile Iron Pipe Research Association,
312/654-2945, with E. Mussler, GCA Corporation. February 6, 1980.
Notebook 3. Call 16.
29. Telecon. Niles, Harry. Ductile Iron Pipe Research Association, with E.
Mussler, GCA Corporation. February 15, 1980. Notebook 3. Call 21.
30. Hoffman, Richard. Scituate Concrete Pipe Company, 617/545-0564.
Personal communication with Ed Mussler, GCA Corporation. February 23,
1980. Notebook 3. Call 25.
31. Chaisson, Roger. Portland Plastic Pipe. 207/774-0364. Personal
communication with Ed Mussler, GCA Corporation. February 28, 1980.
Notebook 3. Call 26.
32. Shea, Steve. Engineer, Boston Water and Sewer Commission, 617/426-6046.
Personal communication with Ed Mussler, GCA Corporation. January 29,
1980. Notebook 3. Call 2.
33. Handbook: Ductile Iron Pipe, Cast Iron Pipe. 5th Edition. Cast Iron
Research Association. Oak Brook, IL. 1978.
34. Patent No. 4118239, Johns-Manville Corporation, Denver, Colorado.
October 3, 1978.
35. Transite Class Pressure Pipe on Transite Sewer Pipe. Pricing Schedule.
Johns-Manville, Denver, Colorado. January 1980.
36. Owen, Gene. American Cast Iron Pipe Company, 201/845-5440. Personnel
communication with Ed Mussler, GCA Corporation. February 26, 1980.
Notebook 3. Call 22.
37. McKanna, Robert. Portland Stoneware, 617/864-7523. Personal
communication with Ed Mussler, GCA Corporation. February 26, 1980.
Notebook 3. Call 23.
38. Andrews, Charles. New England Concrete Pipe, 617/969-0220. Personal
communication with Ed Mussler, GCA Corporation. February 26, 1980.
Notebook 3. Call 24.
39. Manual for Computation of Energy Savings with Ductile Iron Pipe. Cast
Iron Pipe Research Association. Oak Brook, IL.
148
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SECTION 5
ASBESTOS-CEMENT SHEET
ASBESTOS PRODUCT
Special Qualities
Asbestos is used as a reinforcing material in cement sheet products
because of its high tensile strength, flexibility, resistance to heat, chem-
ical inertness, and large aspect ratio (ratio of length to diameter).
Asbestos fiber in cement sheet adds to the strength, stiffness, and tough-
ness of the material, resulting in a product that is rigid, durable, non-
combustible, resistant to heat, weather, and attack by corrosive chemicals,
as well as being stable. A significant feature of the asbestos-cement (A/C)
sheet is that it has sufficient wet strength to be molded into complex shapes
at the end of the production process.1
This section addresses four product categories of A/C sheet:
• flat sheet
• corrugated sheet
• siding shingles
• roofing shingles
Although these categories reflect differences between the .products, they can
be readily covered in one section because the composition and manufacturing
processes used are the same for each of these products.
Product Composition
Asbestos-cement sheet is made from a mixture of Portland cement and
asbestos fiber. Sometimes an additional fraction of finely ground inert filler
and pigment may be included. Sheets contain between 15 and 40 percent asbestos
fiber. In 1980, the Bureau of Mines reports that 7,900* metric tons of chryso-
tile asbestos were used in A/C sheet production, with most chrysotile of grades
6 and 7. One hundred metric tons of grade 5 was also used. No other asbestos :
types were used in A/C sheet production.3
*Down from 35,800 metric tons in 1978.4
149
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Uses and Applications
Today the use of A/C sheet is narrowing toward applications where its
special properties of durability and heat and chemical resistance are not
duplicated by other sheet materials.2
Flat A/C sheet has been used in the construction industry as soffit
material (covering the underside of structural components), roof deck, wall
linings in factories and agricultural buildings, industrial partitions, fire-
resistant walls, curtain walls, and decorative paneling in both exterior and
interior applications. It is also used as cooling tower fill sheets, lab-
oratory table tops and fume hoods, electrical equipment mounting panels, and
as a component of vaults, ovens, safes, heaters, and boilers.' It is found in
schools as well as residential construction.
Asphalt-impregnated flat sheet is used for switchboards, controller
plates, and as an insulating spacer in a wide variety of electrical apparatus.
Corrugated A/C sheet is used primarily in industrial and agricultural
applications, serving as siding and roofing for factories, warehouses, and
agricultural buildings. It is also used as a lining for waterways, canal
bulkheads, and as end paneling for cooling towers.5
Flat sheet can be textured and cut for special use as siding shingles
and as roofing shingles. These shingles are extremely durable, and are
available in a range of styles and colors.6 Another advantage of A/C
shingles is their U.L. Class A fire rating.
Product Manufacturing Summary
Manufacturing Process —
A/C sheet is manufactured by using a dry, a wet, or a wet mechanical
process.
Dry Process — In the dry process, plastic bags containing asbestos
fiber are slit and dumped into a mixer where cement and filler are added.
The resulting dry mixture is uniformly distributed onto a flat conveyor
belt, sprayed with water, then compressed by steel rolls to the desired
thickness. The moving sheet is cut into individual sheets which are removed
from the conveyor and steam cured in an autoclave.7 Cut off saws using
diamond or carborundum wheels are then used to trim the cured sheet to the
desired size or into shingles..8
Wet Process — The wet process begins with the mixing of asbestos
fiber, cement, and additives as in the dry process. Water is added to the
dry mixture and the mix is put in a form where excess water is squeezed out
by a press. After the sheets are formed one at a time in the press, they
are stacked and air cured for 3 to A days, at which time they become rigid..
The sheets may then be steam cured to speed up the curing process.9.
150
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Wet-mechanical process—Used in both A/C sheet and A/C pipe production,
the wet-mechanical process is similar in principle to some papermaking processes.
Asbestos fiber is combined with cement, silica, and other filler material in
a dry mixer and then transferred to a wet mixer. There, underflow solids and
water from the saveall (material being recycled from previous operations) are
added to form a slurry that is pumped to cylinder vats for deposition onto one
or more screen cylinders. Water is removed from the underside of the slurry
layer through fine wire mesh screening around the circumferential surface of
each cylinder.x °
A layer of A/C material from 0.02 to 0.10 inch (0.05 to 0.25 cm) thick is
produced by the above process. This layer is transferred to an endless felt
conveyor so a mat can be built up. More water is removed from the matted
material by a vacuum box prior to transfer of the material to a mandrel, or
accumulator roll. The mandrel winds the mat into a layer of the desired
thickness, and pressure rollers bond the mat to stock already deposited on the
mandrel or roll and help remove additional water as well. As the layer of A/C
material builds up to the desired thickness, it is cut and peeled away. The
resultant sheet can be shaped or molded either by hand or by press roller, and
can then be cut into the desired sheet size. Any of the four product types can
be made by this process.10
Manufacturers use methods such as cylinder showers to clean both the
cylinder screen and the felt conveyor, insuring satisfactory operation of
the process. Cement and fiber particles are washed out of the holes to
prevent "blinding."10
Name and Number of Manufacturers—
There are four major companies currently manufacturing asbestos-cement
sheet products. They are listed in Table 39.
Production Volumes—
Exact production volumes are not known, although it is known that 7,900
metric tons of asbestos was used in 1980 for the production of all types of
A/C sheet products.3
TABLE 39. MAJOR MANUFACTURERS OF ASBESTOS-CEMENT SHEET PRODUCTS
6 > 7
Manufacturer Location A/C products
Johns-Manville Waukegan, IL Flat sheet
Nashua, NH Flat sheet
International New Orleans, LA Flat sheet, corrugated
Building Prod- sheet, siding shingles
ucts, Inc.*
Nicolet, Inc. Ambler, PA Flat sheet
Supradur Mfg. Wind Gap, PA Roofing and siding
Corporation shingles.
*This used to be called Gold Bond Building Products, a Division of
National Gypsum. It was bought out by the new owners this spring.
(Asbestos Magazine, March 1981. p. 32).
151
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SUBSTITUTE PRODUCTS
Methodology
Search Strategy—
Information about A/C sheet products and suitable substitutes was obtained
from special available literature, telephone conversations, and manufacturer's
product specification information.
Summary of Contacts—
Asbestos-Cement Products
• Edmund M. Fenner
Director of Environmental Services
Johns-Manville Corp.
Denver, CO (303) 979-1000
• Richard Mahoney
Gold Bond Building Products
Charlotte, NC (704) 365-0950
e Mr. Kaufman, Assistant Manager
GAF Corporation
South Bound Brook, NJ (201) 356-3000
e Mrs. Smith, Personnel Secretary
GAF Corporation
St. Louis, MO (314) 867-7800
e Judy Gardner
GAF Corporation
Mobile, AL (205) 478-6311
• Bob Muderspach
Celotex Corporation
Lockland, OH (513) 821-3000
• Kurt Schwarz, Senior Vice-President
Supradur Mfg. Corp.
New York, NY (212) 697-1160
e Sales Secretary
Nicolet, Inc.
Ambler, PA (215) 646-4000
Substitute Materials (Flat Sheet)
• John Jones
Cem-FIL Corp.
Nashville, TN (615) 883-7563
152
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• Bill Lewis
GRC Products, Inc.
Schertz, TX (512) 651-6773
• Clare Swanson, Manager of New Applications Division
Conwed Corporation
St. Paul, MN (612) 221-1188
• George Aim
International housing Corp.
Sacramento, CA (916) 456-5343
• Bob Baker
W.B. Arnold and Company
West Caldwell, NJ (201) 575-0880
• Craig Hamling, Sales Manager
Zircar Products, Inc.
Florida, NY (914) 651-4481
• Art McGowen
Masonite Corp.
Laurel, MI (601) 425-3611
Substitute Materials (Corrugated Sheet)
« John Jones
Cem-FIL Corp.
Nashville, TN (615) 883-7563
• William Tyler
Aluminum Company of America
Pittsburgh, PA (412) 553-3922
Substitute Materials (Siding Shingles)
• Art McGowen
Masonite Corp.
Laurel, MI (601) 425-3611
t> Dave Horner
Publishers Forest Products/Cladwood Division
Portland, OR (503) 775-6711
Substitute Materials (Roofing Shingles)
• Jayne Porter, Marketing Assistant
Monier Company
Orange, CA (714) 538-8822
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Substitute Materials (Fibers)
• Jim Ford
Owens-Corning Fiberglass Corp.
Toledo, OH (419) 248-7321
e Dr. Chuck Chaille
Babcock & Wilcox Refractories Division
Augusta, GA (404) 798-8000
• Joe Volk
Gold Bond Building Products/Research Division
Buffalo, NY (716) 873-9750
There are two approaches to replacing asbestos in asbestos-cement sheet.
Either the asbestos fiber can be replaced by a different kind of fiber rein-
forcement, or an entirely different sheet material can be substituted for the
A/C sheet. In any application the qualities or characteristics required of a
sheet material must be considered. Quite often all of the qualities of A/C
sheet are not demanded of a material for a particular application. Consequently,
the suitability and feasibility of a substitute either for the asbestos fiber
or for the whole A/C sheet will be determined to an extent by the demands of
the application in question.
Fiber Substitutes
The most promising substitute fibers for use in place of asbestos in
cement sheet are the specially treated wood fibers used in the cement/wood
board mentioned previously, and alkali-resistant glass used in GRC.
A listing of fibers and their performance characteristics appears in
Table 40.
Product Substitutes
This section includes both the special qualities and the uses and applica-
tions of substitute products for:
• Flat sheet
e Corrugated sheet
e Siding shingles, and
• Roofing shingles
Substitutes for Flat Sheets—
Several cement sheet products containing nonasbestos reinforcing material
were identified as potential A/C sheet substitutes. At least three of these,
a cement/wood board, a glass fiber-reinforced cement sheet, and a plastic-
reinforced concrete sheet, compare favorably with A/C sheet with respect to
density, strength, corrosion and weather resistance, noncombustibility, and
workability.5'12 Others should be useful in more specialized applications.
154
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TABLE 40. PERFORMANCE OF POSSIBLE FIBER SUBSTITUTES FOR
ASBESTOS IN CEMENT SHEET
Fiber Performance and Comments
Alkali-resistant Can be used in Portland cement; better impact
glass resistance than asbestos; product loses strength
with time; commercial feasible.13
Mineralized wood Lightweight; not as heat resistant as asbestos;
superior impact resistance; abundant supply
available; commercially competitive.12
Steel fibers Good reinforcement; high impact strength; problems
with processing and machining; problems with rust,
less expensive than A/C sheet.
Mineral wool Weak product; does not work well in cement.
Carbon fibers Increases modular strength of cement sheet; is
resistant to alkali attack; no increase in impact
strength; very expensive.
Nylon Provides impact strength; lacks reinforcement.
Ceramic fibers No success to date; work is continuing.15
Glass fiber-reinforced cement (GRC) sheet—GRC is presently finding use
in coffin liners, fabrication of fume hoods, cooling towers, permanent formwork
for bridge construction, as fascia and soffit panel, electrical closet liner,
fireproof partitions, wall panels, permanent form boards, storage sheds and
garages, wall liner in factories, decorative trim, and even as road signs and
behind woodstoves if it is U.L. rated.13'16'17 It is now available in commer-
cial quantities in a wide range of thicknesses, from 1/8-inch to 4-inch thickness,
and in basic 4 feet by 8 feet sheets. Corrugated sheets are available in
either the standard U.S. 4.2 corrugation or specialized corrugations such as
the type being developed for bulkhead construction.18
GRC, when compared to A/C sheet, exhibits superior overall strength
characteristics, especially in resisting damage from impacts (it is more im-
pact resistant than asbestos cement over a 28-day period). A/C sheet tends
to crack or break when impacted, while GRC will fail only at the point where it
is struck. GRC sheets have been found to possess an initial strength of 4,000
psi, which stabilizes to 2,000 psi, after 4 to 5 years. This has been improved
to 3,000 psi in new GRC. Industry is debating whether GRC weakens to the
strength of unreinforced cement over time. The asbestos industry claims that
GRC, with the alkali resistant glass, looses impact resistance and strength
with time.19 GRC sheet is noncombustible, weatherproof, rot proof and
corrosion-resistant, although the cement itself may break down eventually in
highly corrosive environments.17 It can be drilled and nailed as well as A/C
155
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sheet, and can also be painted, screwed, glued or bolted. Recent improvements
have been made in the overall strength of the sheet by treating the glass fiber
with a coating that enhances bonding between the fiber and the cement.7 GRC
is lightweight and the raw materials needed for manufacture are readily avail-
able, along with exact, accurate processing techniques.16 GRC satisfies
ASTM-136 and ASTM-E84, and, by changing the density of GRC, thermal conductiv-
ity can be improved.18 However, it is not suitable for all of the corrosion
and heat resistant applications that A/C sheet is used for.19
On the negative side, because GRC has a much lower percentage of fiber
reinforcement than A/C sheet, it shows greater strength loss at 316°C (600°F),
the maximum recommended service temperature for both sheets. Therefore, it is
considered to be less heat-resistant than A/C sheet. Where GRC is exposed for
a short duration with a low rate of temperature rise it probably equals A/C but
with prolonged or high temperature applications such as furnaces and ovens, the
GRC with portland cement will not perform satisfactorily. However, there may
be a possibility of using different cements (such as refractory types) to
provide a GRC for this application. Tests on this are presently underway.18 . _.
GRC does not machine as well as A/C sheet. When cut, the edge tends to
chip, making it unattractive for uses such as lab tables, where appearance is
important. About the only nonasbestos substitute for lab tables is slate,
which is expensive. Tests have shown that GRC suffers about a 30 percent loss
of strength (decrease in value of modulus of rupture) over a period of 30
years, but designing with a proper safety factor could prevent this from
being a serious problem.7'20 As GRC has been marketed for 12 years, production
and marketing technology are well understood, and a wide variety of processes
are now available for high volume production. In addition, work is now pro-
gressing towards production of GRC sheets on standard A/C plant equipment,
although at present, the product (termed hot check made) does not compare in
performance with A/C or with the sprayed GRC. However, it does machine easier
and thus has been adopted by a couple of companies for fume hood construction
for chemical laboratories and industrial plants.17
Cement/wood board—which the manufacturer claims combines the best prop-
erties of wood and cement, has been in use in Europe and the Middle East as
an all-purpose building board for a number of years.12 The cement/wood board
has been rated as noncombustible and is said by some to be virtually impervious
to the influence of any weather condition. However, some argue that cement/
wood boards manufactured in Europe during World War II show poor weather
resistance. Further, they may be susceptible to excessive expansion due to
absorption of water by the wood component during wet weather. This may make
its suitability as exterior cladding questionable, although this tendency
could be combatted through resin saturation, painting, special fasteners
to allow expansion, or incorporation of mica to reduce expansion.17 Its
modulus of rupture and resistance to impact are greater than asbestos-cement
board, and unlike A/C sheet, it can be glued and laminated. Cement/wood
board has good heat and sound insulating properties, is easily machined, and
has surfaces suitable for multipurpose treatment. It also has good elastic
properties under s static load.12 Its weathering characteristics are reported
to be similar to those of marine plywood.17
156
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Applications of the cement/wood board in construction are numerous,
including use as external claddings, sound attenuating walls, balcony parapets
and floors, walls separating gardens, partitions, noncombustible wall and
ceiling linings, roof soffits, roof underlayment (notably in countries with
low supplies of wood), refuse shafts, ceilings, fascia, and lining for farm
stables. It has also been used to build prefabricated houses and pavilions.12
It is often used for interior applications because it is light and flexible.
It is similar to masonite except that it has a portland cement binder rather
than a resin binder. When used as a fill in cooling towers, it may ruin the
efficiency of the tower if it warped. Cement-wood board used in one northwest
U.S. cooling tower is reportedly being replaced by A/C sheet.17
Polypropylene layered cement sheet—A relatively new A/C sheet substi-
tute, this product is comparable to A/C sheet in its resistance to freezing,
thawing, combustibility, and aging. Because it is a type of plastic cement
board, it is flexible and will not fracture as easily as A/C sheet. It is
used for construction of cooling towers, buildings, and other large
structures.21
Alumina-Sheet®—An alumina-silica product made by Zircar Products, Inc.,
this exceeds A/C sheet's resistance to heat. It is available in either a
moldable or rigid form and is being used as an insulator in induction core
applications, as a molten metal transport trough, and as a material for
repairing holes in furnaces. The possibility of using the material for labor-
atory table tops exists as well. Alumina-Sheet is not as strong as A/C sheet,
but has an upper temperature limit several times greater. It is also very
tough and abrasion resistant.22
Benelex —Benelex is a laminated hardboard product produced by Masonite
Corporation, Laurel, Mississippi. It is readily available and is used as lab-
oratory table tops, for floors of locomotives and cabooses, and as a phase bar-
rier in electrical switchgear and control apparatus.23 It is not intended for
uses requiring resistance to weather or high temperature. Laminated hardboard
such as Benelex could replace ebonized asbestos in many electrical applications.
A comparison of selected properties is listed in Table 41.
TABLE 41. COMPARISON OF EBONIZED A/C WITH HARDBOARD:
,24,25
Property Asbestos Ebony® Benelex®
Density, kg/m3 (lbs/ft3)
Rockwell hardness (M scale)
Maximum operating temp. °C (°F)
Arc resistance (seconds)
Insulation resistance (megohms)
1842 (115)
23-85
120 (250)
125
—
1394 (87)
90
90 (194)
85
85.5
Forton—Forton combines GRC with a polymer modified cement matrix. The
polymer adds toughness to the matrix, improves compatibility, and supresses
attack by strongly alkaline hydration products. This technology was developed
by DSM, a Netherland based company with interests in chemicals and building
materials. Fibers used in the U.S. come from PPG's plant in North Carolina.*
^'Information from a letter dated Nov. 17, 1981 to Mr. James Bulman, U.S.EPA,
from Mr. Hiram R. Ball, Jr., Director, North American Operations of Forton.
Product literature was included.
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Monolux®—Monolux is an asbestos-free, noncombustible industrial insulating
board, available from W. B. Arnold and Company. Manufactured by Cape Boards
and Panels Limited (Uxbridge, England), it is rigid, nonfriable, durable,
inert, and resistant to attack by insects and vermin. The board is noncaustic,
unaffected by dilute acids and alkalis, brine, chlorine, or volatile solvents.
It will not disintegrate, warp, or swell under prolonged immersion in water,
and it is more resistant to heat than -A/C sheet. It can be used to make small
ovens and dryers, high temperature ducts, oven shelves and interleaves, and
as secondary insulat-ion for furnaces and kilns.26
Table 42 lists cement sheet products and their characteristics for
comparison with A/C sheet.
Other—Materials such as masonry, galvanized steel, aluminum sheet,
fiberglass-reinforced plastics (especially in cooling towers and even indus-
trial skylights), and wood can compete with A/C sheet in various applications.17
A product such as fiberglass-reinforced plastic is thought to be stronger than
A/C sheet, but flexes more. Polyurethane sandwich panel has also been sug-
gested as a substitute and is apparently used in housing projects in the
southern U.S. for both interior and exterior walls, covered with an aluminum
skin. However, this product may have extremely toxic byproducts upon com-
bustion as the urethane foam might be exposed if the metal sandwich protector
was to fall off. . Alcoa also uses asbestos-free marionite as a substitute
to asbestos-containing marionite (except in the largest diameter mold sizes);
however, this product made by Marietta Resources, Inc., may degrade more quickly
than its asbestos counterpart.30 In this case, suzorite mica replaces the as-
bestos fiber. Wollastonite is also used in some areas; it is reported to be
used in Denmark for example, as a substitute to A/C sheet, but it is not con-
sidered to have the properties required of asbestos at this date. Wollastonite
tends to act like a ceramic.17
Substitutes for Corrugated Sheet—
Corrugated glass-reinforced concrete is already being purchased by
industry to replace damaged A/C panels on buildings. Recent advances in the
glass-reinforcing fiber have improved the wet strength of GRC which has made
the manufacturer more confident of its performance in wet as well as dry
applications. Such uses include canal bulkheads, waterway liners, and as end
panels on cooling towers.5
Depending upon the application, products such as aluminum, galvanized
steel, masonry, or reinforced plastics can be used in place of corrugated
A/C sheet.
Substitutes for Siding Shingles—
Hardboard siding shingles and paneling are available in styles that are
comparable to certain A/C siding shingles. They are very durable, easily
worked, and attractive.31'32
Other siding products popular in the United States are wood, wood
shingles, aluminum, stucco or concrete block, and brick. These products may
or may not be suitable as substitutes for A/C shingles, depending upon the
preference of the customer and the requirements of the application.
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TABLE 42. CEMENT SHEET PRODUCT COMPARISON5'12'22'26'27 29
VO
Product
J/M Transite® (A/C)
J/M Flexboard® (A/C)
Cera-FIL 125 /S
(High density GRC)
Cem-FIL TAG board
(Low density GRC)
Cement /wood board
Mono lux® 500
Alumina-Sheet®
Density
kg An3
(lb/ft3)
1,762
(110)
1,602
(100)
2,000
(125)
1,300
(81)
1,200
(75)
768
(48)
1280 - 1440
(80 - 90)
Maximum
service
temperature
°C (CF)
316
(600)
316
(600)
260
(500)
482
(900)
1,482
(2,700)
Modulus of
rupture
kPa
(psi)
27,580
(4,000)
31,030
(4,500)
27,580
(4,000)
6,895
(1,000)
Young's
modulus
x 106
kPa (psi)
10.34
(1.5)
13.8
(2.0)
13.8
(2.0)
20.7
(3.0)
Tensile
strength
kPa
(psi)
9,650
(1,400)
12,410
(1,800)
11,030
(1,600)
— _
Compressive
strength
kPa
(psi)
82,740
(12,000)
96,500
(14,000)
68,950
(10,000)
41,370
(6,000)
Impact
strength
Nnno/mm
(ft-lb/in2)
4.8
(2)
—
24.0
(10)
~_
__
-------
Substitutes for Roofing Shingles—
Several asbestos-free roofing products are available which have a U.L.
Class A fire rating (the equivalent of A/C shingles). Unreinforced cement
shingles are available in Mediterranean and shake styles. The roof looks
neat and precise and is able to withstand all climatic conditions. No under-
layment is needed in mild climates, and the roof comes with a 50-year warranty.
Asphalt shingles made from a fiberglass base are available. A roof using these
shingles uses two layers of shingles for a thicker, random look, and is fire-
resistant. This type of shingle is made by Johns-Manville and Lunday-Thagard.
An imitation wood shake called CeDurShake® is available from Trim Products.
It is light weight and has a foam backing that acts as an insulator.34
Substitute Product Manufacturing Summary
Product Composition and Manufacturing—
Cement/wood board—is composed of specially treated wood fibers bound by
Portland cement. Wood fibers are treated with various chemicals including
ammonium chloride, sodium and sodium silicate to remove the resins, acids,
and sugars in a process called "mineralization."12 Wet fibers are mixed with
Portland cement and deposited as a mat on individual cauls on a moving belt.
A saw or shear separates the continuous mat into mats whose length corresponds
to the length of the supporting caul. Each caul with its mat of fiber and
cement is transferred to a press where pressure is applied until the cement
has set. A series of mats may be stacked and pressure applied to the stack
by means of retaining clamps for a period of time. When the pressure is re-
leased, the boards are dried.12
Glass fiber-reinforced cement sheet—is basically a composite of a
hydraulic binder (that is, one which required the use of water in order to
get it to set) and materials such as Portland cement reinforced with alkali
resistant glass fibers which are randomly distributed throughout the board.
GRC may or may not require the use of other fillers or additives. If required,
inert fillers such as fine sand or fine silica sand or limestone fines (marble
dust) may be used. Glass fibers are specially formulated to resist the
alkaline attack of the Portland cement. They are typically 1.3 to 3.8 centimeters
long and 13 microns in diameter. These fibers constitute about 5 percent of
the weight of the sheet.27 Additionally, a very small percentage of wood
fiber is used in Cem-FIL Corporation's lightweight TAG® board. Like asbestos
cement, GRC is not just one material but instead a whole spectrum of different
materials, each with performance characteristics varying with the type of
cement used. For example, Portland cement dehydrates at temperatures above
260-316°C, whereas high-aluminum or refractory cement has been tested to
538°C and is good at 316°C, which is similar to J/M asbestos transite board.
Performance can also be affected by the glass fiber content, the type and
quantity of any filler or additive or other mixture that is used, and partic-
ularly the resulting density of the composite.18
GRC sheet can be made by two methods. In the spray-up process used by
Cem-FIL, a gun is used which simultaneously sprays a cement slurry and chops
up a continuous roving of glass fiber into a predetermined length. This
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material is sprayed into a form on a vacuum dewatering bed which draws off the
excess water. The sheet produced can be molded, or stacked and cured.27
Another method of production involves the use of a continuous felt conveyor
belt upon which the cement slurry and chopped glass fibers are sprayed.
Excess water is removed by vacuum boxes attached to the underside of the
conveyor belt. The mat of cement sheet is cut and removed at the end of
the conveyor, then stacked and cured. Corrugated sheets are made by placing
the wet sheet on a form for shaping before curing begins. Sheets are normally
air cured for 28 days.13 GRC sheets have been found to possess an initial
strength of 4000 psi which stabilizes to 2000 psi after 4 to 5 years. This has
been improved to 3000 psi in new GRC.17 Industry is debating whether GRC
weakens the strength of unreinforced cement over time.
Monolux—is made of calcium silicate cement and selected filler rein-
forced with alkali-resistant glass and wood fibers.25 No information about
its manufacture was made known.
Alumina-Sheet—consists of 92 percent aluminum oxide and 8 percent
silica fibers.22 Nothing was learned about manufacturing methods as the
patent is still outstanding.
Benelex—is made from wood. Wood chips are first reduced to fibers by
a steam explosion process. The unwanted elements in the wood are driven
off, leaving cellulose fibers and lignin, a natural bonding agent. The
fiber is refined and then formed into panels on a moving screen. These
panels are placed in steam heated, high pressure presses where the fibers
and lignin are welded together into a dense, hard material.25
Cladwood®—is a medium-density particleboard covered by a refined wood
overlay.2s Hardboard siding such as that manufactured by Masonite Corporation
consists of wood fibers combined with natural bonding agents under high pres-
sure.31 No information about the manufacture of these or other siding products
was obtained.
Monier Company's Monray Roof Tile—is manufactured on a conveyor-type
process from Portland cement, sand and water. A continuous cement mat is
formed on a plastic conveyor, sprayed with the desired color, then cut into
individual tiles at the end. These tiles are cured at 66°C (150°F) for
24 hours, then sprayed with a sealer to prevent salts from rising.35
CeDurShake—is made of fiberglass-reinforced polyester resin.31*
Forton—contains a sand/cement ratio of 0.2 m/m; water/cement ratio of
0.3 m/m; polymer fraction of 0.15 v/v; and glass fraction of 0.05 v/v.
Other—Fiberglass felt is used as the base mat of the new asphalt shingles
made by Johns-Manville and Lunday-Thagard. 31* Other manufacturers of this prod-
uct include: GAF, Celotex, CertainTeed, Bird & Son, and Owens Corning.11
All hough patent status is unsure, Australian Consolidated Industries have
V \ 1 oil fox- an Invention based on clay reinforced with glass fiber. Findings
indicate that the clay matrix does not have the high degree of alkalinity of
cement, such that there is no need to use an alkali-resistant fiber and instead
E-glass fiber is quite satisfactory. Properties substantially conform to
basic requirements of low raw material costs, ready availability of raw
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material, ability to adapt to rapid mass production techniques, physical and
chemical stability and modulus of rupture, density and other physical properties
similar to A/C sheet. Ingredients include glass fiber (generally 5-15 percent) ,
bentonite, ball clays, fillers, fluxes, deflocculants, clay and water. Termed
glass-reinforced stabilized clay (GRSC), not only can this product meet many
A/C product needs, but refutedly, it could possibly be used for such items as
window frames and sills, floor planks, pottery ware and outdoor furniture.36
Still another idea for an A/C sheet substitute, this time in the form of
roofing sheets, comes from the British Intermediate Technology Industrial
Services (ITIS) in Rugby, England. Using ingredients like Portland cement,
sand and natural fibers including human hair cuttings, common grasses, crop
waste from banana, oil palm and coconut plantations or more costly artificial
fibers, developing countries are currently testing out such products to deter-
mine such factors as tensile strength, interaction of the cement and fibers,
and local weathering ability. The production process is kept as simple as
possible for low cost and unskilled labor. Production equipment is fabricated
on-the-spot out of basic components. Reportedly, with good arrangements, it
takes a two-man project team 15 to 20 days to bring about the construction and
operation of a complete sheetmaking unit producing up to 100 sheets a week.
Name and Number of Manufacturers—
Glass fiber-reinforced cement flat sheet is made by Cem-FIL Corporation
in Nashville, TN.* In addition, 60 other companies, such as Concrete Design
Specialties of East St. Paul, MN, make GRC for other specific applications
(here, for use behind wood stoves), some of which would not directly substitute
for. A/C sheet.17 The International Housing Corporation (Sacramento, CA) is
planning to build the first plant in the United States to manufacture cement/
wood board. Monolux is made in England by Cape Boards and Panels, Ltd. (Uxbridge)
and is marketed in the U.S. by W. B. Arnold and Company. Zircar Products, Inc.
(Florida, NY) is the manufacturer of high temperature Alumina-Sheet. Benelex
is manufactured by the Masonite Corporation (Laurel, MI). Other flat sheet
products such as metal, wood and concrete are available from well-known large
manufacturers.
Corrugated glass fiber-reinforced cement sheet is available from the
Cem-FIL Corporation (Nashville, TN). Other possible substitutes for corrugated
A/C sheet as ordinary siding are made by major steel, aluminum and fiberglass
companies.
There are many manufacturers of a variety of siding products. Hard-
board siding shingles and paneling are known to be made by the Masonite
Corporation (Chicago, IL) and Publishers Forest Products, Inc. (Portland, OR).
Unreinforced cement roofing tiles called Monray® Roof Tiles are made by
the Monier Company (Orange, CA). Fiberglass-based asphalt shingles are
currently available from Johns-Manvilie Corp. (Denver, CO) and Lunday-
Thagard (Southgate, CA) and will be available from most major asphalt roof-
ing manufacturers by the end of the year. 31* CeDurShake® is made by Trim
Products (Torrance, CA). Table 43 presents a summary of substitute manufac-
turers and products.
*GRC Products, Inc. of Schertz, TX once made GRC sheet but has since gone out
of business.lx»37
162
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TABLE 43. SUBSTITUTE PRODUCT MANUFACTURERS
5>12>13>22»23»26>32-3i»
Manufacturer
Cem-FIL Corporation
Forton
Location
Product and name
Nashville, TN Flat and corrugated glass-reinforced
cement sheet (125S, TACboard®)
Dallas, TX*
Forton-GRC plus polymer
International Housing Sacramento, CA Cement/wood board flat sheets
Corporation
Cape Boards and Panels, Uxbridge, U.K. Calcium silicate cement sheet
Limited (Monolux®)
Zircar Products, Inc.
Masonite Corporation
Publishers Forest
Products, Inc.
Monier Company
Johns-Manville
Corporation
Lunday-Thagard
Trim Products
Florida, NY
Laurel, MI
Chicago, IL
High-temperature alumina-silica
sheet (Alumina-Sheet®)
High-density wood laminate (Benelex®)
Hardboard siding shingles and
paneling
Portland, OR Hardboard siding shingles and
paneling (Cladwood®)
Orange, CA Unreinforced cement roof tiles
(Monray® Roof Tiles)
Denver, CO Fiberglass-reinforced asphalt
shingles
Southgate, CA Fiberglass-reinforced asphalt
shingles
Torrance, CA
Fiberglass-reinforced polyester
shingles (CeDurShake®)
*Currently, Forton has plants and warehouses in New Jersey and Texas, where all
the materials are stored. The polymer compound will be made in the Dallas
area, with the possiblity of producing it in five other U.S.locations as the
market develops. Fibers are provided from PPG in North Carolina. (Forton
letter of Nov. 17, 1981 to James Bulman, U.S. EPA.)
163
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Fiber reinforcing materials for cement sheet are being investigated by
several companies, including Babcock & Wilcox (Augusta, GA), Conwed Corp.
(St. Paul, MN), and Gold Bond Building Products (Buffalo, NY). No informa-
tion about actual production has been released; Conwed has, however, just
received a patent for their product.
GAF Corp. filed a patent in 1975 for a cotton-cement sheet product
consisting of cement, cotton fiber, inorganic filler, silica and water.38
There is also a Swiss patent, filed in 1978, for a fiber reinforced cement
material using short polyvinyl alcohol fibers..39
Production Volumes—
The International Housing Corporation has not yet begun to produce
cement/wood board, but plans to manufacture 11,150 m2/day (120,000 ft2/day)
when production begins.1*0
GRC Products, Inc. is currently able to manufacture 557,700 to 929,500 m2
(6 to 10 million ft2) of flat sheet per year.13 Cem-FIL Corp. has not yet
begun to produce large quantities of GRC, but currently manufacturers to fill
orders.18
No other information on production volumes is known. However, plywood,
particleboard, hardboard, steel, fiberglass, and concrete are fairly abundant.
COST COMPARISON
Costs are broken down into sheet categories for comparison, including
flat sheets, corrugated sheets, siding shingles and roofing shingles.
Flat Sheet Substitutes
According to a product cost comparison between cement/board and A/C
sheet done by the cement/wood board manufacturer, the most expensive mill
price of cement/wood board is less than half the cost of J/M Flexboard® A/C
sheet and less than one-fourth the price of J/M Transite® A/C sheet.12
Glass fiber-reinforced cement sheet is expected to be competitive with
A/C sheet in the future,13 although the price of glass fiber is higher than
asbestos fiber at present.17 Like many other materials, the economics depend
very much upon the volume of production. With low-volume production of quar-
ter inch spray GRC sheet, costs run about $1.20 per square foot, whereas this
price can be lowered to 80
-------
Alumina-Sheet is more than 10 times as expensive as Transite, but the
price is expected to be cut in half as production increases this year.
Although the cost is high for Alumina-Sheet, in one instance, the Alumina-
Sheet was used to replace asbestos rollboard as a pouring trough liner for
zinc alloys. The Alumina-Sheet lasted 6 months while the asbestos rollboard
was replaced every other day. Because Alumina-Sheet is fairly new on the
market, additional comparisons are not currently available.
Table 44 snows a comparison of prices.
Corrugated Sheet Substitutes
Steel is less expensive than A/C sheet and aluminum is competitive.7
Corrugated GRC is more expensive, at 2 to 2-1/2 times the cost of A/C sheet.5
Table 45 shows a price comparison between siding products from quotations
made in California in 1979.12
Roofing Shingle Substitutes
Monier Monray roof tile, CeDurShake, and the new fire-resistant asphalt
shingles cost between $100 and $130 for a square (a 100 ft roof surface),
installed. Supradur asbestos-cement shingles would cost (per square) about
the same as these substitutes.12
CURRENT TRENDS
There is a growing interest in substitutes for A/C sheet. A large manu-
facturer of laboratory fume hoods is buying GRC panels for construction mate-
rial, and a major manufacturer of appliances is actively seeking substitutes
for A/C sheet in pizza ovens.5 Cooling tower companies are seeking products
that can replace A/C sheet in cooling tower construction (in fact, the first
full scale use of GRC in a large cooling tower is currently underway in
Kentucky),18 and owners of factories are purchasing corrugated GRC to replace
damaged A/C sheets at their facilities.5 GRC is used quite extensively on
the West Coast in high-rise buildings where it is designed and has been
tested out to be capable of taking shocks such as seismic loading.18 The
representatives of companies either producing substitute cement sheet or
planning to make asbestos-free cement sheet report a growing positive interest
from other parties using or needing A/C sheet. 5 5l 3 5lfo
The construction of a plant producing large quantities of flat glass-
reinforced concrete sheet has shown that a nearly equivalent (and in some
respects superior) substitute for A/C sheet can be produced at a competitive
price.13 This has occurred in the face of predictions that GRC would not be
able to compete with A/C sheet. The move by International Housing Corporation
to introduce cement/wood board to the United States will bring to the market-
place a material that has the potential to replace A/C sheet in general con-
struction applications, not only from the viewpoint of material performance
characteristics but also because of its relatively low cost. Cement/wood
board could also easily be made into textured siding and roofing shingles that
165
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TABLE 44. COMPARISON OF CEMENT SHEET PRODUCT
PRICES 12>13>18'22»26»'*1»1*2
Cost ($) per m2 (ft2)
Product
J/M Flexboard (A/C)
J/M Transite
(A/C)
Cement/wood board
High density
Low density
For ton
GRC
GRC
Alumina Sheet
6
25
2
8
8
3.90-4.
160
1/4 in.
.50
.00
.70
.60
.60
90
.00
(0.
(2.
(0.
(0.
(0.
60)
30)
25)
80)
80)
15
35
5
21
16
1/2 in.
.00
.00
.40
.00
.00
(1
(3
(0
(1
(1
.40*)
.28)
.50)
.95)
.50)
(0.36-0.45)
(15.
00)
—
*Prices are given at the distribution level; they depend on the
quantity of the material ordered. Here, a quantity of over
1000 sq ft is assumed for the J/M products.
TABLE 45. COMPARISON OF SIDING PRODUCT
COSTS12
Total cost ($)
Product perm2 (ft2)3
Wood siding, 5/8 in. 8.75 (1.00)
Wood shingle 15.75 (1.50)
Asbestos-cement shingle 13.50 (1.25)
Fiber board 10.75 (1.00)
Brick or stone 61.75 (5.75)
Stucco or concrete block 18.00 (1.75)
Aluminum 13.50 (1.25)
o
All costs include material price for
plywood sheathing of $0.25 ft2, except
the wood siding cost.
166
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would likely be a substantial challenge to A/C roofing and siding shingles, if
they were produced.12 Other roofing materials that are fire-resistant are
prominent in California where fire is a persistent threat.31* Some of these
products have the potential to replace A/C roofing shingles. Aluminum and
vinyl siding have reportedly forced A/C siding from the residential market
except where special fire protection is required or where a slate-like
appearance is desired.31
In the past 2 years, GAP Corporation and Celotex Corporation have phased
out the manufacture of all A/C sheet, and National Gypsum has just sold
its Gold Bond Building Products A/C sheet plant in Louisiana (see
Table 39).5 As previously mentioned, several large companies, including two
manufacturers of A/C sheet, are developing or experimenting with fibers that
would effectively serve as substitutes for asbestos in cement sheet. The
current trend seems to be a move towards the use of asbestos-free sheet
materials.
CONCLUSION
Asbestos-cement sheet still stands as a versatile, all-purpose material
that is relied upon for its excellent durability, heat resistance, work-
ability, and relatively low cost. This unique combination of qualities has
until now given it an unrivaled niche in various markets in the United States.
Glass-reinforced concrete appears to be suitable for most corrosion and
heat resistant applications where A/C is currently employed, and work to
improve the resistance of GRC sheet to heat is continuing.5* Cement/wood board,
once it is actually under production, should be a cheaper material than A/C
sheet for general construction purposes. This product has been used in Europe
for a number of years, thus allowing time to test its performance. Unique
properties include its ability to be glued and laminated (A/C sheet cannot);
it also has a greater modulus of rupture and resistance to impact than A/C
sheet. Questions of weather resistance capabilities now being debated may be
combatted by solutions such as resin saturation or special paints in the future.
Substitutes are available for many specialized applications as well.
No material that can adequately match A/C sheet's qualities as a lab
table is available, though other products are currently used. (Slate is one
of the materials used here but it is inordinately expensive.) At this time
no single material could replace ebonized asbestos sheet in all electrical
applications, but Benelex® has been shown to be a usable substitute for some.
In the past there have been no economical, physically comparable substi-
tutes for A/C sheet, but the products described in this section have changed
that. While no single product matches A/C sheet's qualities exactly (companies
such as Johns Manville claim that all nonasbestos sheets degrade more rapidly
than asbestos), there are products that can be identified as suitable sub-
stitutes for A/C sheet for most applications. With new replacements, some
recognition of the performance requirements of the end use has to be clarified
*In addition, the Forton product discussed is both available and suitable in
this product line.
167
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with the user; such requirements have often been neglected in favor of the
ease of A/C in that the decision has been made in the past. However, with
properly defined requirements, many of these substitute products can adequately
fulfill niches delegated to asbestos in the past, even though this may require
a certain amount of testing and design work to come up with the right thickness
and formulation to make the alternative product work. Most substitutes are
currently more expensive than A/C but the differential is shrinking. In the
case of GRC, it has shrunk from approximately a 5 to 1 price differential, to
a current cost of about one and a half times that of the asbestos product.
168
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REFERENCES
1. Pye, A. M. A Review of Asbestos Substitute Materials in Industrial
Applications. Journal of Hazardous Materials (Amsterdam), v. 3: 125-147.
1979.
2. Telecon. E. M. Fenner, Director of Environmental Services, Johns-
Manville Corp., Denver, Colorado, (303) 979-1000, with S. Duletsky,
GCA/Technology Division, February 4, 1980. Notebook No. 05, Phone call
No. 35.
3. Clifton, R. A. Preprint from the 1980 Bureau of Mines Minerals Yearbook,
U.S. Department of the Interior, p. 4.
4. Clifton, R. A. Asbestos in 1978. United States Department of the Interior,
Bureau of Mines. Division of Non-Metallic Minerals, Washington, D.C.,
Annual Advance Summary. August 1979.
5. Telecon. J. Jones, Assistant General Manager, Cem-FIL Corp., Nashville,
Tennessee, (615) 883-7563, with S. Duletsky, GCA/Technology Division,
January 31, 1980. Notebook No. 05, Phone call No. 25.
6. Supradur Manufacturing Corporation, New York, N.Y. Manufacturer's liter-
ature on Mineral Fiber Shingles.
7. Meylan, W. M., et al. Chemical Market Input/Output Analysis of Selected
Chemical Substances to Assess Sources of Environmental Contamination:
Task HI. Asbestos. Prepared for OTS, EPA, Washington, D.C., August 1978.
8. Weston, Roy F., Environmental Consultants. Technological Feasibility and
Economic Impact of OSHA Proposed Revision to the Asbestos Standard
(Construction Excluded). Asbestos Information Association/North America.
March 26, 1976.
9. Roy, N. Final Trip Report to Johns-Manville Corporation A/C Plant in
Nashua, New Hampshire. GCA/Technology Division, Bedford, Massachusetts.
October 23, 1979.
10. U.S. Environmental Protection Agency. Development Document for Effluent
Limitation Guidelines and New Source Performance Standards for the Building,
Construction, and Paper Segment of the Asbestos Manufacturing Point Source
Category. February 1974.
11. AIA Comments on May 1981 Substitutes to Asbestos Report by GCA Corporation/
Technology Division Received by GCA 10/22/81.
169
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12. International Housing Corporation. Notebook containing information about
Cement/Wood Board. Sacramento, California. 1979.
13. Telecon. W. H. Lewis, GRC Products, Inc., Schertz, Texas (512) 651-6773,
with S. Duletsky, GCA/Technology Division, February 11, 1980. Notebook
No. 05, Phone Call No. 50.
14. Cogley, D. R. speech entitled "Other Substitutes for Asbestos-Cement
Sheet" presented at the July 1980 EPA/CPSC Conference "Substitutes
to Asbestos." Found in "Proceedings of the National Workshop on
Substitutes for Asbestos," p. 133.
15. Telecon. C. Chaille, Babcock & Wilcox Refractories Division, Augusta,
Georgia, (404) 798-8000, with S. Duletsky, GCA/Technology Division,
January 30, 1980. Notebook No. 05, Phone call No. 20.
16. "Now! A Strong, Fireproof, Weather Proof, Nonasbestos, Construction
Board" GRC Products Inc. 17051 I.H. 35 N. Shertz, TX 78154.
17. EPA/CPSC Substitutes Conference, July 14-16, 1980, Arlington, VA. A/C
Sheet Roundtable Discussion.
18. Jones, John, Cem-FIL Corporation, Speech presented at EPA/CPSC Substi-
tutes to Asbestos Conference, Arlington, VA. July 14-16, 1980.
19. Pigg, B. J., A.I.A., Letter to R. Guimond, EPA, August 12, 1980.
20. Fiberglass Limited. Cem-FIL 2 Alkali Resistant Glass Fibre. Cem-FIL
Product Leaflet Yf2. St. Helens, Merseyside, England. October 1979.
4 pages.
21. Telecon. C. Swanson, Conwed Corporation, with S. Dultesky, GCA/
Technology Division.
22. Telecon. C. Hamling, Zircar Products, Inc., Florida, New York,
(914) 651-4481, with S. Duletsky, GCA/Technology Division, February 5,
1980. Notebook No. 05, Phone Call No. 38.
23. Telecon. A. McGoweri, Manager Sales Administration, Central Hardboard
Division, Masonite Corporation, Laurel, Mississippi, (601) 425-3611,
with S. Duletsky, GCA/Technology Division, February 14, 1980. Note-
book No. 05, Phone Call No. 56.
24. Johns-Manville Corporation. New Asbestos Ebony and Ohmstone®. J-M Product
Leaflet IN-229A 10-61. Denver, Colorado. 4 pages.
25. Masonite Corporation. Benelex<§> 402: Industrial Laminate Electrical
Insulation. Product Description and Specification Sheet Form 908304.
Laurel, Mississippi. 2 pages.
26. Cape Boards and Panels, Ltd. Monolux® Industrial Handbook. M1077914.
Uxbridge, England.
170
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27. Jones, J., and T. Lutz. Glass Fiber Reinforced Concrete Products—
Properties and Applications. Journal of the Prestressed Concrete
Institute, v. 22 (3). May-June 1977.
28. Johns-Manville Corporation. Flat Transite—The Basic Building Material
of 1001 Uses. BSD-31A. Denver, Colorado. March 1976. 4 pages.
29. Johns-Manville Corporation. Flexboard Mineral Fiber Sheets, BSD-23A.
Denver, Colorado. 4 pages.
30. Vaudreuil, Michael, ALCOA Corp., Lauren Choate, NYCO, and Irv. Huseby,
General Electric. Roundtable discussion during EPA/CPSC "Substitutes
to Asbestos" Conference, Arlington, VA. July 14-26, 1980.
31. Masonite Corporation. Siding: 1980. Form 902180. Towanda, Pennsylvania.
20 pages.
32. Publishers Forest Products. Cladwood Quality Siding—Durable, Beautiful,
Economical, Pub. 101678 ML 40M 3/79. Portland, Oregon.
33. Monier Company. Monray Roof Tile Information Package. Orange, California.
34. Smaus, R. Roofing Reaches New Heights. Home, a Supplement of the Los
Angeles Times. January 27, 1980. pp. 8-11.
35. Telecon. J. Porter, Marketing Assistant, Monier Company, Orange,
California (714) 538-8822, with S. Duletsky, GCA/Technology Division.
February 15, 1980. Notebook No. 05, Phone call No. 70.
36. Castleman, B. I., and S. L. Berger. Asbestos Substitutes Technology.
July 8, 1980.
37. Telecon. N. Krusell, GCA/Technology Division, 11/30/81. Notebook No.
012, p. 29.
38. U.S. Patent No. 4,040,851, "Cotton-Cement Articles," B. R. Ziegler,
Inventor. Filed May 30, 1975.
39. U.S. Patent No. 4,199,366, "Fiber Reinforced Cement-Like Material,"
P. Schaefer, Inventor. Field November 20, 1978.
40. Telecon. G. Aim, International Housing Corporation, Sacramento,
California, (916) 456-5343, with S. Duletsky, GCA/Technology Division.
January 29, 1980. Notebook No. 05, Phone call No. 11.
41. Telecon, J. Bostian, Asbestos Fabricators, Inc., Charlotte, North
Carolina (704) 377-3461, with S. Duletsky, GCA/Technology Division,
March 7, 1980. Notebook No. 05, Phone call No. 90.
42. Telecon. M. Flachbart, Kenneth Industrial, Marblehead, Massachusetts,
(617) 631-6866, with N. Roy, GCA/Technology Division, September 22, 1980.
Price is for a 1 x 1 foot piece.
171
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SECTION 6
FLOORING PRODUCTS
ASBESTOS PRODUCT
Two asbestos-containing flooring products are considered here: vinyl-
asbestos floor tile and sheet vinyl flooring with asbestos backing. The felt
carrier for the vinyl flooring was covered as a paper product previously.
Although the vast majority of asbestos used in this category is for vinyl-
asbestos products, there is also a very small amount of asphalt-asbestos floor
tiles produced. Potential substitutes for floor tile and sheet vinyl products
are discussed. It will be noted that different asbestos fiber grades and
different manufacturing methods are used in the production of these two
products, although they are treated together in one report section.
Special Qualities
Asbestos has been used in flooring production chiefly because of its
qualities in two areas: end use (consumer product) properties and manufac-
turing properties. In the consumer field, asbestos offers floor tile and
sheet flooring the following advantages:
• dimensional stability,
e durability,
9 resilience,
o flexibility,
« resistance to moisture, chemicals, fire, fungus, etc., and
• good indentation strength.1
Dimensional stability is provided by the continuous web of asbestos fibers
within the floor tile, which help to prevent shrinkage or expansion from
change in temperature. Durability is also important in floor tile, as it may
be in place for up to 30 years in heavily trafficked areas. Asbestos not
only provides an interlocking matrix that offers this needed durability, but
also gives the tile resilience due to the nature of the fiber itself
(especially the shorter grades) and provides indentation strength to the
tile surface. The fibers impart flexibility to the tile, preventing
cracking and breaking during installation or use. Resistance to moisture,
chemicals, fire and fungus, as well as chemicals and oils and other
potentially damaging substances which can effect floors, is also inherent
in asbestos.
172
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In addition to benefiting the floor tile in the manner delineated above
(during use), asbestos is also essential in the manufacturing process cur-
rently used. Here, asbestos fibers provide mill tack, heat resistance, and
dimensional stability. The mill tack allows the tile material to adhere to the
roll mills; the heat resistance protects the product from potential cracking in
the manufacturing process, and the dimensional stability is critical to prevent
the sheet from appreciably shrinking or expanding. Without these qualities,
production techniques and machinery would have to be altered or replaced to
provide for continuous production.
Product Composition
Vinyl-asbestos tile compositions vary with manufacturers and the type of
tile produced, but the asbestos content of the tile usually ranges from 8 to
30 percent by weight, or up to 0.13 pounds of asbestos per square foot of tile.2
Grades 5 and 7 are normally used. Tiles are typically produced in 9 x 9 or
12 x 12 inch sizes, with thickness ranging from 1/32 to 3/32 inches. PVC resin
serves as the binder and makes up from 15 to 25 percent of the tile. Chemical
stabilizers usually vary little from 1 percent of the total formulation. Lime-
stone and other fillers represent 43 to 73 percent of the weight (depending on
reference used), while pigment content usually averages about 5 percent, but
may vary widely depending upon the materials required to produce the desired
color.2'3
Sheet backing for vinyl flooring is composed of about 85 percent asbestos
and 15 percent latex binder.2
Uses and Applications
In 1975* asbestos flooring commanded a 91 percent share of the resilient
floor covering market.3 Of this total, 38 percent was floor tile and 53 per-
cent was sheet flooring. Only 9 percent of the resilient floor covering mar-
ket was held by nonasbestos-containing products, mainly solid vinyl flooring.
Vinyl-asbestos floor tiles and sheet vinyl flooring are installed in
industrial, commercial, institutional, and residential buildings.2'3 They may
be installed on concrete, prepared wood floors, or over old tile floors, and ;
are often specified for heavily trafficked areas such as kitchens, entry ways,
restrooms, supermarkets, commercial plants and offices. Their chief competi-
tors in the flooring market are hard surface floors, such as terrazo, ceramic
tile, brick and stone, as well as wood floors and carpet.
Product Manufacturing Summary
Manufacturing Process—
Vinyl-asbestos floor tile—Vinyl-asbestos floor tile is an outgrowth of
asphalt composition sheet and, as a result, has been conventionally formulated
with asbestos so that its processing and performance characteristics would
match those of the asphalt composition as closely as possible. ** The manufac-
ture of vinyl-asbestos floor tiles varies from company to company. However, the
general flow of raw and finished materials is similar throughout the industry.3'5
*Data for more recent years were not available.
173
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Ingredients for tile production, including raw asbestos fiber, pigment,
and fillers, are weighed and mixed dry in a Banbury mixer. The mixer works
the dry materials into an agglomerated plastic mass. As the material is
sheared in the Banbury, the asbestos, fillers, and pigments are dispersed
throughout the vinyl mass. Liquid constituents, if required, are then added
and thoroughly blended into the batch. While the mechanical working of the
material itself generates heat, more heat may be added, if required, to raise
the batch temperature to 300°F (150°C) and flux the polymer resin.
The warm plastic mass is then fed to a mill where it is joined with
recycled scrap and undergoes final mixing. From this point on, the process
is continuous. The mill consists of a series of hot rollers that squeeze
the mass of raw tile material down to a desired thickness. During the milling
operation, surface decoration in the form of small colored chips of tile
(mottle) may be sprinkled onto the top of the raw tile sheet and pressed in
to become a part of the sheet. Some tile has a surface decoration embossed
and inked into the tile surface during the rolling operation.
After milling, the tile passes through calendars until it reaches the
required final thickness and is ready for cooling. Tile cooling is accom-
plished in many ways and a given tile plant may use one of several methods.
Direct water contact in which the tile is immersed in, or sprayed by water,
is one method. Indirect water cooling utilizing water-filled rollers is
another. Some plants pass the tile through a refrigeration unit to cool the
tile surface. After cooling, the tile is waxed, stamped into squares, in-
spected, and packaged.. Trimmings and rejected tile squares are chopped up
and reused. Asbestos in the floor tile is thought to be completely encap-
sulated when it is shipped,
Sheet vinyl flop-ring (flooring carrier, flooring felt) — is an asbestos
paper product which forms the underlayer of sheet vinyl flooring. The backing
is produced on a paper machine, following production techniques outlined in
Section 2 of this report. During manufacture, the asbestos fibers are coated
with latex and are reported to be fully encapsulated when the sheet backing
is readied for use in the manufacture of sheet vinyl flooring. The major
steps in the manufacture of sheet vinyl flooring are coating, printing, fusion,
trimming and packaging. The flooring may be manufactured in the same plant
as the sheet backing or in a separate facility.2
Production of sheet vinyl flooring begins with a coating operation. Here
the sheet backing is coated with a latex and/or plastisol coating. These
coats are applied by reverse roll coaters or blade coaters. Once the coatings
are applied, the sheet is passed through an oven where these layers are dried
and jelled. The coated sheet is then transported to a printing operation where
one or more engraved cylinders transfers designs to the coated sheet. In some
cases, there will be several printing stations which separately apply one color
or aspect of the design patterns. The printed sheet then goes to a fusion step
where the sheet is coated with another layer of material called the "wearlayer."
The wearlayer is a homogeneous polymer application that provides an impervious
surface for the finished product. The coated and printed sheet is next fed
through an oven where the backing itself, the layers of latex and plastisol
and the wearlayer are fused into a single product. After fusion, these layers
174
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remain distinct but are no longer chemically or mechanically separable.
vinyl sheet is then cooled, cut to size, packed and shipped.
The
Name and Location of Manufacturers—
The major manufacturers of asbestos-containing resilient floor covering
and their plant locations are presented in Table 46. The manufacturers sell
floor tile directly to retailers, lumber yards, etc.; there are no secondary
fabricators in this industry.
TABLE 46. MAJOR U.S. MANUFACTURERS OF ASBESTOS FLOORING
2 » 3 >6
Plant location
Manufacturer
Vinyl asbestos tile*
Sheet backing
American Biltrite, Inc.
Amtico Flooring Division
Armstrong World In-
dustries, Inc.
Congoleum Corporation
Resilient Flooring
Division
GAF Corporation
Consumer Products Group
Kentile Floors
Mannington Mills, Inc.
Uvalde Rock Asphalt
Azrock Floor Products
Division
Trenton, New Jersey
Norwood, Massachusetts
South Gate, California Fulton, New York
Kankakee, Illinois
Jackson, Mississippi
Lancaster, Pennsylvania
Cedarhurst, Maryland
Long Beach, California
Vails Gate, New York
Brooklyn, New York
Chicago, Illinois
Salem, New Jersey
(Sheet vinyl)
Houston, Texas
Whitehall, Pennsylvania
*The Flooring Division of the Flintkote Company used to produce vinyl as-
bestos floor tile, but, according to contact with the East Rutherford, 18
N.J. headquarters, no asbestos floor tile is currently produced.7 Winburn
Tile Manufacturing Co. of Little Rock, AR has also ceased producing V/A
floor tile.8
Production Volumes—
Asbestos fiber consumption for the resilient floor covering industry was
estimated to be 126,000 metric tons in 1978 but by 1980 this figure was down
to 36,080 metric tons.9 Of this amount, approximately 40 percent or 14,400
metric tons was used in vinyl-asbestos floor tile and the remainder in sheet
(felt) backing for vinyl sheet flooring. Only the chrysotile form of asbestos
is used in tile and felt production.
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SUBSTITUTE PRODUCT
Methodology
Search Strategy—
A combination of a literature review of relevant trade journals and a
survey of industry representatives was used to gather data on potential vinyl
asbestos floor tile substitutes.
Summary of Contacts—
The following industry representatives were contacted to gather data on
potential vinyl asbestos floor tile and sheet substitutes.
• Mr. Robert Mauer
Resilient Floor Covering Institute
1030 15 St., NW, Suite 350
Washington, D.C.
• Mr. Robert Luders
Sales Administrator
Armstrong Cork Company
Fulton, New York
• Mr. Paul Graham
Monsanto Company
800 N. Lindbergh Blvd.
St. Louis, Missouri
• Mr. Jack Clegg
Kentile Floors
Brooklyn, New York 11215
• Mr. Frank Andrejak
Amtico Flooring Division
American Biltrite, Inc.
Trenton, New Jersey 08607
• Company Representative*
The Flintkote Company
Flooring Division
Dallas, Texas 75221
• Company Representative *
GAF Corporation
Consumers Product Group
New York, New York 10020
• Company Representative *
Mannington Mills, Inc.
Salem, N.J.
*The name of the person contacted at this company was not obtained.
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Fiber Substitutes
Special Qualities—
A few companies are investigating various fibers to act as substitutes to
asbestos in flooring tile. Some attempts have been made to introduce such
fibers now being experimented with in other asbestos product areas such as roof-
ing, paints, and sealant products. ° To date however, little is known about
specific special qualities that such fibers might display, as the information
is kept proprietary by the flooring industry in efforts still underway to test
and further develop such potential floor tile substitutes. It is known that
Santoweb® (discussed below) may be used in existing manufacturing processes
and can withstand temperatures of 149°C during calendering. "*
In addition, another fiber product by Lextar using Pulpex looks promising.**
This product exhibits a melt strength of 10, on a scale of 0-10, and tensile
properties (using ASTM D-638 as a guide) at 180°F of 59-72 psi strength and
3 to 22 percent elongation. At 23°C, it exhibits 980-1170 psi strength,
0.29-0.49 percent elongation and for modulus, 365,000-445,000 psi. Water di-
mensional growth has also been tested and, after immersion at 30°C for 1 to 14
days, there was no growth measured.11
Product Composition—
One product currently under research at Monsanto Corp. is called Santoweb
and is composed of cellulose fibers.12 Lextar of Wilmington, Delaware is ex-
perimenting with a synthetic polyolefin pulp product that they call Pulpex®.10
Georgia Bonded Fibers produces Bondex 148 in both Europe and the United States,
which is used as sheet flooring underlay.13
Information on product composition is available for the Pulpex® product
only. Formulations for this product include PVC resins - Butyl Benzyl phthalate
plasticizer, stabilizers; fillers-powdered CaCC^, crushed limestone; and
fibrous fillers-pulpex.lx
Uses and Applications—
The uses and applications for these substitute fibers are similar to those
of asbestos. Included is vinyl sheet and tile flooring as well as the use of
Pulpex® in the roofing and sealant markets.10
Product Substitutes
Special Qualities—
Product substitutes include the traditional vinyl-asbestos floor tile
competitors: solid vinyl tile, rubber tile, wood, carpet and hard surface
floors. Linoleum was also a competitor in the early years of sheet vinyl
(late 1950's), but by 1974, the asbestos sheet had virtually replaced the
linoleum product. Although these products each have special qualities, in
general they also possess negative aspects that offset the special qualities
*Also includes one formulation where asbestos can be used here. Both
Pulpex E (from polyethylene) and Pulpex P (from polypropylene) are used here.
**It should be noted that this product is as yet only in preliminary stages of
development and evaluation.
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when compared to the asbestos product. This includes less resistance to
abrasion or chemicals and less flexibility as in solid vinyl tile. Rubber
tile does not resist grease. Linoleum put in place in the past has shown
itself to be less stain resistant and more apt to be affected by alkali
materials. A product such as carpet is more porous and thus wears at an in-
creased rate. In general, the wear resistance is just not on the same level
as that of the vinyl asbestos product. However, some products, such as that
now under development by Union Carbide of New York, NY, are reported to exhibit
properties closer to those of asbestos, including good flexibility and indenta-
tion resistance. **
Product Composition—
The major vinyl-asbestos tile manufacturers are researching new asbestos-
free tile formulations. The Armstrong Cork Company, for example, offers an
asbestos-free vinyl floor tile called Stylistic. Asbestos has been replaced
by increasing the limestone and resin contents of the tile.11* In addition,.
Mannington Mills produces sheet vinyl flooring without asbestos.15 Union
Carbide Corporation has combined at least two normally-solid thermoplastic
vinyl chloride polymers to form their floor-tile composition.4 Their patent was
submitted in 1974. Other manufacturers are also investigating the use of solid
vinyl and vinyl blends in their new formulations. These new blends appear to
use increasing amounts of resins, binders and fillers in place of asbestos,
although specific formulations are confidential.
Advantages/Limitations—
Each of the traditional vinyl-asbestos floor tile competitors lacks one
or more of the advantages of vinyl-asbestos tile. Solid vinyl tile, for exam-
ple, is generally not as abrasion resistant, chemical resistant or as flexible
as vinyl-asbestos.16 Rubber tile, while resilient, is difficult to maintain and
is not grease resistant. Linoleum has a lower resistance to alkali materials
and stains.16 Carpeting is less resilient, more porous and therefore less
durable.2
In general the new asbestos-free tile formulations lack wear resistance
and have not been extensively field tested, although these substitutes exhibit
some qualities similar to the vinyl-asbestos floor tile. For example, the
Union Carbide product, purported to be a "novel floor-tile composition" reputedly
exhibits a combination of acceptable processing characteristics including good
indentation resistance, good flexibility, improved light resistances, and very
Low water sensitivity."* Often processing refinements are required to improve
the dimensional stability of the new asbestos-free tile products. Other design
changes will require both time and capital expenditure.1
Product Manufacturing Summary—
Production methods for the new tile substitutes are not known, but are
expected to be similar to vinyl-asbestos tile manufacturing techniques. For
example, production of the Union Carbide substitute mentioned in the previous
paragraph is reputed to be conveniently adaptable to existing "asbestos tile"
equipment and production lines.1* Lextar's Pulpex is dry blended in a Henschel
mixer.11 Table 47 lists the current manufacturers of nonasbestos floor tile.
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TABLE 47. MANUFACTURERS OF SUBSTITUTES TO
VINYL/ASBESTOS FLOOR TILE
Company
Location^
Monsanto Corporation
Georgia Bonded Fibers
Lextar
St. Louis, MO
Newark, NJ;
Buena Vista, VA
Wilmington, DE
Union Carbide Corporation New York, NY
Lancaster, PA
Armstrong Cork Company
aThomas Register, 1980.
Production Volumes—
There is a lack of data on current production volumes of these substitute
items as most information is proprietary. Some products are still in testing
stages.
COST COMPARISON
Armstrong Cork's asbestos-free floor tile costs 25 to 50 percent more
than its asbestos counterpart. For the floor tile formulations discussed for
Pulpex, cost is reported to be approximately $14.55 per 100 Ibs on a weight
basis; the formulations with one type of Pulpex, for a specific grade, is 11.3
percent more expensive than the asbestos formulation given. For the Pulpex
vinyl floor tile, Lextar estimates a cost of approximately $1.30 per Ib (F.O.B.
supplier). This can be compared to 0.37 C/lb for Firestone's PVC resin floor
tile; 0.51 c/lb for Monsanto's "Santicizer"; approximately 0.049 C/lb for
H. M. Royal's (distributor) "atomite CaC03"; 0.012 C/lb for their crushed
limestone vinyl floor tile; and finally 0.09 C/lb for an asbestos formulation.11
CURRENT TRENDS
The flooring industry is, overall, secretive with its innovative studies
at this time and will not share technologies. There are tremendous costs
involved in research and development for substitutes. Further, the firm which
finds an acceptable substitute could make a large profit and perhaps control
the entire market.18
CONCLUSION
There are no commercially-available substitutes which duplicate all the
manufacturing and end use product advantages of vinyl-asbestos flooring
products. While products are available which can be used in place of vinyl-
asbestos floor tile and sheet flooring, none of these appears to have the low
cost, durability, dimensional stability and resistance qualities of asbestos.
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New products are being introduced into.the market which may ultimately replace
asbestos, but they have yet to be universally tested and do not now enjoy
widespread use. However, some already established products such as carpeting,
even though they lack the wear resistance, are causing the V/A floor tile, as
well as the entire resilient floor covering share of the flooring market
to decrease at its expense. It has been estimated that up to 10 years will be
required to develop, test and market an asbestos fiber replacement for this
area of use. However, companies such as Lextar may succeed in shortening
this time period if current product testing proves successful.
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REFERENCES
1. A characteristic partially imparted by asbestos, as noted in a letter to
R. Guimond, EPA, from B. Pigg, A.I.A., 12 August 1980.
2. Cogley, D. , et al. Life Cycle of Asbestos in Commercial and Industrial
Use Including Estimates of Releases to Air, Water and Land. Draft Copy.
GCA Corporation. October 1979. GCA-TR-79-73-G.
3. Comments on the Advance Notice of Proposed Rulemaking on the Commercial
and Industrial Use of Asbestos Fibers. The Resilient Floor Covering
Institute. Washington, D.C. , February 18, 1980.
4. U.S. Patent No. 3,904,579. R. P. Braddicks, Inventor. Filed August 14,
1974.
5. Mclnnes, R. Final Trip Report - Kentile Floors, Inc., Brooklyn, N.Y.,
December 3, 1979.
6. Meylan, W. M., et al. Chemical Market Input/Output Analysis of Selected
Chemical Substances to Assess Sources of Environmental Contamination:
Task III - Asbestos. EPA-560/6-78-005. August 1978.
7. Telecon. Mrs. Benny, Flintcote Co., Central Ave., East Rutherford, N.J.,
with Anne Duffy, GCA Corporation, GCA/Technology Division, (201) 368-9700,
April 15, 1981, Call No. 11.
8. Telecon. Ralph Chambers, Winburn Tile Manufacturing Co., Little Rock,
Ark. , with Anne Duffy, GCA Corporation, GCA/Technology Division,
(501) 375-7251, April 16, 1981, Call No. 17.
9. Clifton, R. A. Mineral Industry Survey. Asbestos in 1978. U.S. Bureau
of Mines. August 22, 1979, and Clifton, R. A. Preprint from the 1980
Bureau of Mines Minerals Yearbook on Asbestos, p. 4.
10. Smith, D. A., Lextar, Letter to R. Guimond, EPA, February 22, 1980.
11. Lextar - A Hercules/Solvay Company, Wilmington, Delaware. Product
Information. Tables 2 and 3 - Pulpex Vinyl Floor Tile Formulations.
12. Telecon. Paul Graham, Monsanto Company, St. Louis, Mo., with David R.
Cogley, GCA Corporation. March 1980.
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13. Georgia Bonded Fibers, Inc. Response to EPA's Advance Notice of Proposed
Rulemaking on the Commercial and Industrial use of Asbestos Fibers.
Docket No. OTS-61005, December 13, 1979.
14. Telecon. Robert Luders, Sales Administration, Armstrong Cork Co., with
Ron Bell, GCA Corporation. February 28, 1980. Notebook 1, Call 18.
15. Telecon. Company Representative, Mannington Mills, Inc., Salem, N.J.,
with N. Krusell, GCA Corporation, January 1981.
16. Flooring Materials Encyclopedia of Polymer Science and Technology,
Volume 7, pp. 78-96, John Wiley and Sons, Publishers.
17. GAF Corporation response to EPA's Advance Notice of Proposed Rulemaking
on the Commercial and Industrial Use of Asbestos Fibers. Docket No.
OTS-61005, February 7, 1980.
18. Plastics and Floor Tiles Roundtable Discussion. "Substitutes to
Asbestos" Conference, USEPA/CPSC, Arlington, Va. July 14-16, 1980.
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SECTION 7
GASKETS AND PACKINGS
ASBESTOS PRODUCT
Special Qualities
Gaskets and packings are found in virtually every mechanical, chemical,
and thermal operation or device where fluids are involved. Although both
gaskets and packings are used to seal one fluid from another, the primary
difference between the two lies in their application. Gaskets are used where
no motion occurs relative to the bearing surfaces, whereas packings are
applied in situations where motion will take place. Consequently, gaskets
provide static seals while packings provide dynamic seals. In some
applications, packings are also available which allow a controlled amount of
leakage.
Asbestos has been used successfully in both applications because of its
unique combination of qualities. It is not only heat resistant, resilient,
and strong, but it is also relatively chemically inert, which is important for
many chemical applications. Both gaskets and packings are normally composed
not only of asbestos but also some form of elastomeric binder and, in the case
of some packings, a lubricant.1 The asbestos imparts its strength, heat
resistance, and chemical inertness to the gasket while the binder holds the
fibers together.
Assuming the gasket is properly designed for its operating temperatures
and pressures, the service life of asbestos gaskets is influenced essentially
by two factors: (a) the reaction of the fluid being contained with the binder
and (b) scheduled and nonscheduled maintenance of the device being sealed.
Although asbestos is essentially chemically inert, the binder used with the
asbestos fibers can be affected by the fluid being contained causing the
product to fail due to binder properties rather than to the asbestos itself.
Selection of the gasket with the most inert binder for the particular
application is extremely important. Maintenance, whether scheduled or
nonscheduled, prematurely shortens the service life of the gasket by requiring
replacement of the gasket, which has been damaged while the seal is broken.
The service life of asbestos packings is determined primarily by wear due
to friction. Therefore, a lubricant is generally included in the binder. In
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the case of pumps, the pump packing must leak to perform properly. Their
purpose is to control leakage, not to prevent it. This slight leakage along
the shaft provides proper lubrication to the packing. Pump packings have a
lubricant which acts as a primary sealant for start-up and break-in phases,
during which time the lubricant reduces friction. However, once the pump is
on line, external lubrication must be supplied to the packing to keep it
running properly and ensure the longest life possible. If not, the lubricant
in the packing will bleed out due to heat generation causing the packing to
fail.
A valve is packed differently than a pump. In contrast to a pump packing
which must leak, a valve packing must not leak. Pressure and temperature on a
valve stem packing is normally much higher than on a pump packing. To
eliminate the possibility of the lubricant bleeding out of the valve packing,
the packing is impregnated with a minor amount of sealing material. Valve
stem packings must provide a dense structure that will not permit movement of
the fluid through the body of the packing itself, thus acting more like a
gasket.
Product Composition
Specific gasket and packing ingredient formulas vary with manufacturer
and grade of product. The proportion of fiber and binder in the gasket varies
with the temperature of its intended use. Commercial grade asbestos sheet
contains 75 to 80 percent asbestos and is used for temperatures up to 204°C
(400°F).2 Temperatures of 483°C (900°F) or higher require gasket sheet of
99 to 100 percent asbestos.2 Both white chrysotile and blue crocidolite
asbestos are used to about 483°C (900°F).2 AAAA asbestos can withstand
temperatures up to 538°C.^ Above this temperature, the chrysotile becomes
unstable due to the release of combined water, and crocidolite
predominates.^> ^
Asbestos content in packings varies considerably—up to 100 percent for
some applications such as sealing furnace doors.-'- For most applications,
however, a binder/lubricant is impregnated into and onto the fibers. Some
typical elastomeric binders used in the packing and gasket industry
include: ^>6
• silicone based rubber,
• neoprene,
• Buna-N rubber,
• natural rubber,
• nitrile rubber,
• Teflon®
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• glue-glycerine,
• styrene-butadiene,
« nitrile Buna-N, and
e Hypalon®.
Some" of the mbre common lubricants used in packing manufacture are:^-
• petroleum based oils and waxes,
« high grade animal fats and waxes,
• Teflon,
9 mineral oil,
• natural rubber,
• Buna-S rubber,
• vegetable oil,
• glycerine, and
« graphite.
For some applications, a lubricant may not be necessary.
The consumption of asbestos for this product category was 12,300 metric
tons in 1980, most of which was chrysotile.^
Uses and Applications
The uses and applications of asbestos gaskets and packings are extreme.
In order to classify these applications, one must look at three primary
parameters: (a) the operating temperature, (b) the operating pressure, and
(c) the nature of the fluid being serviced. Operating temperatures vary from
almost absolute zero (-273°C or -460°F) in cryogenic applications up to 538°C
(1000°F).l Operating pressures range from a vacuum up to 3.45 x 10^ kPa
(5000 psi). The nature of the fluid serviced is perhaps the most important
parameter to be considered. The list of fluids is almost endless. For
instance, one gasket and packing manufacturer lists over 700 materials to aid
in selecting the proper packing.•*• This manufacturer has assigned a service
classificaton to each of the materials on the list as well as to all of the 94
different packings the company produces. The classifications are:
a. general,
b. caustic,
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c. pulp and paper,
d. food,
c. waLcr,
f. solvents,
g. acids, and
h. any of the above uses except strong acids where the pH is between 0
and 2.
Although packing is generally sold by weight, it is used by increments of
length.
Product Manufacturing Summary
Manufacturing Process—
Asbestos gaskets—There are several methods of gasket production
currently in use. Basic steps in manufacture include fiber introduction,
mixing, sheet formation, cutting and stamping, and packaging. As beater-add
gaskets are discussed in the paper products section, only compressed sheet
gaskets will be addressed here.
Raw ingredients including asbestos fiber, elastomeric binder, and a
solvent are preweighed and added to a mixer; this mixture is then blended on a
batch basis until a dispersed agglomerated mass is obtained. This operation
may be wet or dry according to product requirements- A large roll is
typically 40 inches in diameter by 130 inches in length and produces a sheet
120 inches square. This calendered gasket sheet is then cut to size and
packaged. The sheet may be stamped into products onsite, or, more commonly,
sold to secondary manufacturers for further processing or to distributors for
the maintenance market. Secondary fabricators, such as gasket cutters,
generally form gaskets from sheets by die cutting while the maintenance user
cuts the sheet manually.
Asbestos packings—Asbestos-based packings are manufactured by a variety
of processes. The most common process is impregnation of dry yarn with a
lubricant.
After lubricant impregnation, the yarns are braided into a continuous
length of packing which is in turn calendered to a specific size and
cross-sectional shape.. The formed product may then be coated with more
lubricant or even with another material. It may then either be coiled, boxed,
and sold to the maintenance trade, or instead be pressed into required shapes
at the place of manufacture. Fiber or yarn may also be used as a reinforcement
to elastomers and molded to desired cross-sectional shapes.
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Another type of packing production involves the extrusion of a mixture of
fiber, binder, and lubricants and subsequent braiding of lubricated asbestos
yarns over the extrusion. Most final cutting and forming operatons are done
by secondary fabricators.
Names and Number of Manufacturers—
Primary gasket and packing manufacturers are listed in Table 48. Actual
annual asbestos use for each plant is unavailable. Although primary products
such as compressed sheet and impregnated yarn are made by the 26 primary
manufacturers listed, much of the material is packaged and resold by a large
number of specialty companies. These secondary manufacturers typically rework
the gasket sheets and packing yarn into desired shapes and may sheath them in
metal, plastic, or cloth or reinforce them with wire insertions. Due to the
wide variety of gasket and packing sizes, shapes, sheathing materials and
asbestos compositions available, no distinct, all-inclusive product list can
be made. Similarly, the number of companies involved in secondary fabrication
is impossible to pinpoint, although one 1975 estimate suggested that more than
200 such operations exist.2
Production Volumes—
In 1980, approximately 12,300 metric tons (MT) of asbestos were used in
the United States to produce gaskets and packings. Of this amount, 12,200
metric tons was chrysotile and the remaining amount was crocidolite.' In
1978, 31,100 metric tons of asbestos were used in this category.^0
SUBSTITUTE PRODUCT
Methodology
Search Strategy—
A combination of a literature review and survey of industry
representatives was used to gather data on asbestos gaskets and packings and
their potential substitutes.
Summary of Contacts—
The following industrial representatives were contacted to obtain
information on asbestos packings and gaskets and their possible substitutes.
• Mr. C. Stein, Pars Manufacturing Co., Ambler, Pennsylvania, January
1980.
0 Mr. G. Faber, E. I. DuPont de Nemours & Co., Inc. Wilmington,
Delaware, January 1980.
e Mr. H. Stiegler, Excelsior, Inc., Rockford, Illinois, January 1980.
• Mr. S. Dittmeir, Norton Company, Sealants Division, Granville, New
York, January 1980.
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TABLE 48. U.S. ASBESTOS GASKET AND PACKING MANUFACTURERS
2,8
Name
Location
10
Araetex Corporation
Anchor Packing
9
Armstrong Cork Co.
Braiding and Packing Works of America
A. W. Chesterton
Crane Packing
Detroit Gasket & Mfg. Co.
F. D. Farnum
Felt Products Mfg. Co.
Fitzgerald Gasket
GAF12
Garlock, Inc.
Greene, Tweed & Co.
13
Hollingsworth & Vose
TIT14
Janak, Inc.
Johns—Manvilie
Lamont Metal Gasket Co.,
16
McCord Corporation
Nicolet Industries
Parker Seal Gaskets"1
Raybestos-Manhattan, Inc.
Richardson Corp., Hercules Div.
Sacomo Packing Co.
Sacorao-Slerra
SEPCO
Standee Rubber Gaskets
18
Norristown, PA
Manheim, PA
Fulton, NY
Brooklyn, NY
Everett, MA
Morton Grove, IL
Detroit, MI
Necedeh, WI
Skokie, IL
Torrington, CT
Erie, PA
Charlotte, NC
North Wales, PA
East Walpole, MA
Weatherford, TX
Manvilie, NJ
Waukegan, NJ
Houston, TX
New Orleans, LA
Wyandotte, MI
Ambler, PA
North Brunswick, NJ
Stratford, CT
Alden, NY
San Francisco, CA
Carson City, NV
Birmingham, PA
Houston, TX
aMost of these companies were originally noted in the references
listed, then verified by telephone contact by GCA personnel;
locations for a few were verified by the 1980 Thomas Register.
In addition, an unpublished OSHA document on Asbestos was used.
^Manufacture asbestos-containing material that eventually goes
into gaskets and packings.19
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• Mr. T. Connolly, Janos Industrial Insulation Corp., Moonachie, New
Jersey, January 1980.
• Mr. J. Minchella, Miller Products Company, New York, New York,
January 1980.
• Mr. R. Swanson, Garlock, Inc., Mechanical Packing Division,
Charlotte, North Carolina, February 1980.
• Mr. C. Broecker, Newtex Industries, Inc., Victor, New York, January
1980.
a Mr. B. Holt, Melrath Gasket Co., Philadelphia, Pennsylvania,
February 1980.
• Mr. E. Fenner, Johns-Manville, Denver, Colorado, January 1980.
e Mr. M. Call, Boise Cascade, Specialty Paperboard Division, Beaver
Falls, New York, February 1980.
• Nicolet, Inc., Ambler Division, Ambler, Pennsylvania, February 1980.
• Mr. E. Huber, Paramount Packing and Rubber, Baltimore, Maryland,
Feburary 1980.
• Mr. J. Buechel, Durabla Manufacturing Co., Paoli, Pennsylvania,
February 1980.
• Gaddis Engineering Co., Port Washington, New York, February 1980.
• Mr. T. Conaghan, Bently-Harris Mfg. Co., Lionville, Pennsylvania,
February 1980.
• Mr. S. Koehler, Greene, Tweed & Co., North Wales, Pennsylvania,
February 1980.
• Mr. R. Chiostergi, E. I. DuPont de Nemours & Co., Inc., Wilmington,
Delaware, February 1980.
o Mr. V. Bunch, Sheller Globe Corporation, Norfolk, Virginia, February
1980.
a Mr. L. Hall, Southland Industries Incorporated, Norfolk, Virginia,
February 1980.
a Mr. M. Black, Armco, Hitco Materials Division, Gardena, California,
February 1980.
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Fiber Substitutes
Special Qualities—
The special qualities of substitute fibers for gasket and packing
applications are summarized belovj.
Silica fibers—High melting temperature and continuous working
temperature, resistant to many chemicals, high tensile strength, exhibit no
creep.
Ceramic fibers—High melting temperature and continuous working
temperature (greater than silica), no shrinkage or moisture absorption, good
flexibility and chemical resistance. Coramic 249, a product of Dana Corp.,
resists temperatures up to 1260°C (2300°F), and exhibits extremely high crush
resistance.21 Ceramics have a temperature range up to 1650°C (3000°F);
their compressive strength is more than twice that of asbestos. Problems
include the fact that the binders necessary to keep the systems intact
disintegrate at these temperatures. In addition, ceramics are up to 30 times
the diameter of asbestos, which makes homogeneity a problem. For high
temperature exhaust gas applications however, ceramics may be blended with
other fibers to make an acceptable alternative.22
Graphite fibers—Heat and chemical resistant, long service life,
lightweight, will not harden, near zero thermal expansion and drip rate.
Graphite products by Dana Corp., including Victocor and Solicor withstand
extreme temperatures, and in the case of Solicor, have maximum radial strength
provided by a solid steel core. 1
Aramid fibers—Aramid fibers have tremendous tensile strength and
modulus, while maintaining flexibility in some grades. They begin degrading
at 260°C (500°F) but do not disintegrate or gasify at that temperature. At
1095°C (2000°F) they have higher strength than asbestos. They are being used
in compounds in small quantities.22
Teflon fibers—Will not stain, chemical resistant, low frictional
properties.
Product Composition—
Silica fibers—Many different forms of silica fibers are currently on the
market.z-}~-° Although slightly different in form, silica fibers are
essentially pure Si02- Products are produced in various forms including
cloth, Irish cloth (treated with chromia), slit tape, woven tape, sleeving,
yarn, cord, bulk, fiber, batting, and rope.25
Ceramic fibers—Ceramic fibers are typically metal oxides, nitrides, or
carbides, available in various forms including continuous filament, cloth,
tube, rope, tape, and chopped fibers.26,27 Products by Victor Products
Division of Dana Corp. containing ceramic materials are the Coramic series.
Coramic 199 consists of a steel layer on one side, with soft material on the
opposite side. Coramic 299 is a soft material core mechanically held between
two steel outer layers. Coramic 249 is ceramic material applied to a
perforated steel core, and 439 is soft material facing on both sides of a
perforated steel core.21
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Graphite fibers—Graphite fibers are available in various forms including
plain or diamond textured tape and sheet, die formed rings (with and without
wire mesh insertions), cloth, rope, yarn, cord, and bulk fiber.28,29 These
products are black in color. One manufacturer claims a product with nominal
filament diameter of 0.076 mm (0.0003 inches).28 Victocor 189 by Victor
Products is composed of graphite sheet reinforced with a perforated steel
core; Victocor 289 combines this with an adhesive and Solicor 689 is graphite
sheet chemically bonded to a solid steel core. -^ K
Aramid fibers-^O—E. I. DuPont de Nemours & Co., Inc., has been granted
the generic name "aramid" by the Federal Trade Commission for its family of
aromatic polyamide fibers which include Kevlar® 29, Kevlar® 49, and Nomex®.
Kevlar 29 will be discussed in this section because it is widely used in the
gasketing and packing industry. Both Kevlar and Nomex are discussed in detail
in the Textiles Section of this report. DuPont produces Kevlar 29 in filament
yarns and stable fibers.
Teflon® fibers^l—Teflon TFE-fluorocarbon fibers and resins were
developed by E. I. DuPont de Nemours & Co., Inc. Teflon fibers possess a
higher degree of molecular orientation than their resin counterparts.
Consequently, the ultimate strength and resistance of the fibers to cold flow
is much greater than that of the resins. Teflon fiber is available as a
continuous multifilament yarn, staple, flock, or tow. the natural color of
Teflon is dark brown. Pure white bleached fiber is also available.
Uses and Applications—
No single substitute fiber material possesses all of the high qualities
exhibited by asbestos; however, for any particular application, a substitute
fiber can often be employed to achieve the desired combination of properties.
Fiber replacements whose composition has been detailed include: silica,
graphite (carbon), aramid (Kevlar), ceramic, and Teflon fibers (see Table
49). Table 50 compares asbestos with these fibers. Disadvantages of asbestos
including especially its abrasive properties for packing use and its
insulation abilities, have caused the development of substitute products which
excel in these areas. For instance the normally positive insulating abilities
of asbestos trap frictional heat within the stuffing box containing the
packings, which can in turn boil the lubricant and suspensoids out of the
packiiig. In addition, this build-up heat is transferred along the pump shaft,
which may eventually overheat the bearings, causing a failure and shutdown of
the entire pump assembly for major repairs. As a result, substitute packings
have been developed which provide greater heat dissipation than asbestos. The
abrasive qualities of asbestos, causing it to grind when compressed as a
packing against a rotating shaft (as in a stuffing box) and thus requiring
lubricants and maintenance programs to get around this potential problem, have
also been avoided with substitute products. Although the costs of nonasbestos
packings might seem higher than those of asbestos packings, when operating and
maintenance costs are considered, the newer synthetic packings are
competitive. Only Teflon packings presently meet FDA regulations for contact
with food, drugs, cosmetics, and medical devices,^5 however, Grafoil^6 by
Carborundum is reported to be close to FDA approval for its use relative to
food additives, and Aramid products may also be approved.^
191
-------
TABLE 49. CHARACTERISTICS OF FIBERS
Maximum
tensile strength
Continuous duty
temperature limits
Fiber (106 kPa) (106 psi) Lower (°C) Higher (°C) Chemical deterioration References
so
to
Silica 3450
Ceramic 1720
Graphite 2070
Kevlar
Teflon
2758
359
500
250
3000
400
52
-73
-200
-46
-268
990
1400
3000
200
290
some molten metals, hydro-
fluoric acid, fluorides,
oxides, hydroxides
23, 32, 33
hydrofluoric acid, phosphoric 26, 28, 29
acid, hot concentrated alkalis
strong oxidizing compounds, 29, 34
chromium (VI) and permanganate
solutions
strong acids including: hydro- 30
chloric, hydrofluoric, nitric
and sulfuric
certain perfluorinated organic 31
liquids at temperatures above
299°C (570°F)
Asbestos 3450
500
-273
540
essentially none
-------
TABLE 50. FIBER USAGE CHART3
Fiber
Advantages
Disadvantage
Most common usage
Asbestos Heat resistant
Pressure resistant
Strong (Tear resistance)
Availability
Price
Heat insulator
Abrasive
Health hazard
Messy
Low service life
Fluid
compatibility
Depending on brake and
and lube: General
service pumps, valves,
etc.
Aramid Super strong
Tear resistant
Hard to cut
Cannot be die
formed
3-11 pH range
Papermill—stock pumps
hydrofiner etc.
Sewage treatment
plants—centrifuge
260°C Temp. Limit sludge pumps, etc.
All slurries in 3-11 pH
range.
Possible future replace
all TFE/Asbestos
Graphite/ Reduces run in time
TFE Chemical resistant
Composite Low thermal expansion
Nonscoring
Good heat dissipation
Light weight (more
feet per pound)
Not messy
Nonstaining
Flexible
Will not extrude
A product you can
standardize on
Great in valves
Long service life
If over tight-
ened, it may
glaze
Possible price
Chemical pumps espe-
cially effective on
chemical slurries
Sewage/slurries
General service
TFE
Low friction
Chemical resistance
Nonasbestos
Nonstaining
Thermal
expansion
Low shaft speed
260°C limit
Possible price
Chemical pumps and
valves
Food and drug pumps and
valves
Nonstaining applications
(continued)
193
-------
TABLE 50.(continued)
Fiber
Advantages
Disadvantage
Most common usage
Carbon Heat dissipation
yarn Takes high shaft speeds
Least expensive in the
carbon/graphite family
Temperature resistant
to 649°C in steam
Operates with a lower
drip rate
Repack costs reduced
total removal not
always necessary
Brittle
Possibly
The best boiler feed
pump packing going
especially the large
ones in power plants
Chemical pumps
Boiler recirculation
pumps
This is a good general
power plant packing
Graphite Heat resistant
Heat dissipation
Fastest shaft speed
Chemical resistance
Long service life
Light weight
Near zero thermal
expansion
Near zero drip rate
A viable alternative
to the mechanical seal
Will not harden
Brittle
Frays
Price
In the dry form, it is
used in high tempera-
ture valve in power
plants
High speed-low drip
rate pumps
Very hot chemicals
Chlorine agitators
Exotic high temperature
and highly corrosive
materials
194
-------
As was the case in packings, the aforementioned materials are also
suitable substitutes for asbestos in many gasket applications. If the
application is under 260°C, compressed asbestos sheet gasketing can be
immediately curtailed by applying a substitute material. Graphite sheet,
metal gaskets, and Rogers Corp. gaskets-'" can replace asbestos over 260°C
but their use consitututes a major expenditure to plant maintenance. Victor
Products gaskets have found use as exhaust system gaskets sealing combustion
gases under severe operating conditions. Here they have been shown to have
superior heat resistance as compared with their asbestos counterparts,
frequently withstanding temperatures of up co 2200°F (1204°C), while still
maintaining a seal during extreme temperature changes. This product is
available in seven material compositions, ranging in application from exhaust
manifolds, exhaust pipe flanges, turbo-charger mountings and catalytic
converters. Victor's hard gaskets are used as cylinder head and intake
manifold gasketing materials. Their soft gaskets resist engine coolants,
fuels and lubricants.21
Other candidates for gasket applications include glass fiber, coated
metals, and, in some areas, cellulose fiber. Glass fiber normally withstands
heat to 595°C (1100°F) at which point softening and fusing occurs. Glass has
good strength and displays the highest surface area (thinnest diameter) of any
manmade fiber. It is recommended in reinforcing mica, clay, or baryte-based
compounds, much in the same way aramids and nylons are expected to be
used.^^ Coated metals are reported to display the physical strength of the
substrate metals, coated with a well-bonded yet embossable sealing coating of
nitrile or silicone. No wicking is necessary due to the solid steel barrier.
Good relaxation and extrusion properties have been exhibited.22 Cellulose
fiber is favored in some applications, although it is only used sparingly in
such areas as materials requiring high temperature resistance, due to its low
charring temperature. However, where heat is less than 150°C (300°F), it can
be used as a successful carrier web or matrix for a variety of fillers.22
In addition to fibers for packings and gaskets, filler materials are
important in creating nonasbestos substitutes for this category. Fillers
include clay and mica. Clay is inexpensive, compressible in bulk, and fills
the voids between the larger fibers such as glass, nylon, or aramid. When
clay is added to most materials, it increases the surface area to the
magnitude of asbestos. Clays are easily dispersed in water mixtures. For
sealing, clay reduces the spring rate of the facing as well as improving the
load bearing capabilities. Clay resists temperatures to about 1650°C
(3000°F). In addition, clay has better conformity properties than
asbestos. 2 Mica has been used for years by the paper industry as a
filler. Chemically or thermally expanded, it becomes vermiculite, which is
very economical, has high surface area, and good temperature resistance [above
1095°C (2000°F)] Although it has relatively low strength, it has good slip
characteristics, caused by the low coefficient of friction of the particle.
Compared to asbestos, mica displays better torque and heat resistant
properties.
195
-------
Performance of Substitutes—
General—Greene, Tweed & Co., a supplier of gaskets and packing, have
developed a method of selecting a dynamic service packing based on three
important criteria: PV and pH factors and the material's resistance to
temperature.^ The PV factor, which is the factor for mechanical conditions,
is determined by multiplying the pressure of the stuffing box by the velocity
of the shaft. The resultant PV factor will pinpoint a range of applicable
packings. The Fluid Sealing Association has developed a chart showing this
range, which is presented in Table 51.
The pH factor is a numerical measurement of the intensity of severity of
an acid, which in turn determines the potential amount of chemical attack a
packing will encounter. Table 52 shows which packings are applicable to a
specific pH factor.
The third and equally important criterium is resistance to temperature.
Aramid, Teflon and Graphite/TFE composites are generally limited to 260°C.
Carbon yarn is rated to 649°C in steam or 343°C in oxidizing atmospheres.
Coramic, by Victor Products, resists temperatures up to 1204°C (2200°F).21
Pure graphite goes all the way up to 3316°C in nonoxidizing atmospheres, 649°C
in steam, and 427°C in oxidizing atmospheres. An important factor to consider
as far as temperature goes is frictional heat. If the surrounding atmosphere
in which the packing must perform is close to the temperature limit of the
packing (within 21-38°C), then careful attention must be paid to proper
break-in of the packing, and maintaining adequate drip rates to enhance
cooling and heat transfer away from the packing and delicate pump components.
Even though packing materials such as graphite could withstand the heat, the
crystalline structure of the metallic pump components could be altered,
causing degradation and failure; in addition, oil seals and bearings may
succumb to the heightened temperatures, also causing shutdown for major
overhaul.^
Table 53 represents an attempt to compare the various packing materials
discussed here in a practical manner. It is titled "Experimental Preference
Rating Chart," because the ratings are based on testing experience, and take
i-nto account more than just the three factors discussed previously. Service
life of the packing, efficiency of energy usage, and equipment life are the
three criteria which give an experimental rating. The highest a product can
be rated is 100, and the lowest a product can be rated is zero. As is clearly
seen in Table 53, each substitute material presented provides superior ratings
over asbestos in packings.
Fiber Substitutes —
Silica fibers—Silica fibers will not melt or vaporize until temperatures
exceed 1704°C (3100°F).32 Continuous working temperatures of up to 982°C
196
-------
TABLE 51. PV FACTORS3
vO
-vl
Stuffing box Graphite/TFE
Pressure velocity, fpm PV factor Temp., °F Aramid Carbonaceous TFE composite
0-50 psi 52-916
51-100 psi 916-1885
101-174 psi 916-1885
175-250 psi 916-1885
50-150 X
151-500 X
45>800 501-600
601-750
50-150 X
188,500 151-5°° X
501-600
601-750
50-150 X
151-500 X
328>°°° 501-600
601-750
50-150
471,300 151-5°°
501-600
601-750
X X
X X
X
X
X X
X X
X
X
X X
X X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
-------
TABLE 52. pH FACTOR DETERMINES CORRECT
FACTOR MATERIALS3
pH range . Applicable packing materials
0-1 TFE Fiber
Carbonaceous Fiber
Graphite Tape
Graphite/PTFE Composite
PTFE Impregnated Carbon
2-3 ' TFfi Fiber
Carbonaceous Fiber
Graphite Tape
Graphite/PTFE Composite
PTFE Impregnated Carbon
4-5 TFE Fiber
Carbonaceous Fiber
Aramid TFE-Dispersion
Graphite Tape
Graphite/PTFE Composite
PTFE Impregnated Carbon
6-7 TFE Fiber
Carbonaceous Fiber
Graphite Tape
Cellulostic
Aramid TFE-Dispersion
Graphite Tape
Graphite/PTFE Composite
PTFE Impregnated Carbon
8-9 TFE Fiber
Carbonaceous Fiber
Cellulostic
Aramid TFE-Dispersion
Graphite Tape
Graphite/PTFE Composite
PTFE Impregnated Carbon
10-11 TFE Fiber
Carbonaceous Fiber
Aramid TFE-Dispersion
Graphite Tape
Graphite/PTFE Composite
PTFE Impregnated Carbon
12-13 TFE Fiber
Carbonaceous Fiber
Graphite Tape
Graphite/PTFE Composite
PTFE Impregnated Carbon
14 TFE Fiber
Carbonaceous Fiber
Graphite/PTFE Composite
PTFE Impregnated Carbon
198
-------
TABLE 53. EXPERIMENTAL PREFERENCE RATING CHART3
Application data Service 1 Service 2 Service 3
Motion Rotary Rotary Rotary
Fluid Clear, Neutral Slurry, pH 6-8 Acid Slurry, pH 2
Temperature 93°C 93°C 204°C
Shaft Speed . 800 FPM 800 FPM 200 FPM
Discharge Pressure 50 psi 50 psi 150 psi
Drip Rate 100 Drops/Min. 100 Drops/Min. 20 Drops/Min.
Flush No Yes Yes
Asbestos Asbestos Asbestos
Service Life
Energy Use
Equipment Life
40
10
5
40
10
5
10
10
5
Aramid Aramid Aramid
Service Life 60 100 10
Energy Use 60 60 60
Equipment Life 70 70 70
Graphite/TFE Graphite/TFE Graphite/TFE
Composite Composite Composite
Service Life
Energy Use
Equipment Life
90
80
80
90
80
80
100
80
80
Teflon Teflon Teflon
Service Life
Energy Use
Equipment Life
90
90
60
90
90
60
25
90
40
Carbon Carbon Carbon
Service Life 95 95 95
Energy Use 90 90 90
Equipment Life 90 90 90
Graphite Graphite Graphite
Service Life 100 100 100
Energy Use 100 100 100
Equipment Life 100 100 100
199
-------
(1B()0°F) do not reduce the strength or flexibility of the; fibers.23 Working
temperatures as low as -73°C (-100°F) have been reported.33 The functional
cycling temperature of select fiber forms approaches 650°C (1200°F). The
tensile strength of silica fibers is temperature dependent, varying from 3.45
x 106 kPa (500.00 psi) at 22°C (72°F) to 1.72 x 106 kPa (250,000 psi) at
538°C (1000°F)^3 However, another manufacturer23 of silica fibers claims
that working temperatures of up to 982°C (1800°F) do not reduce the strength
or flexibility of the fibers although some embrittlement and shrinkage occur
above 982°C (1800°F). In addition to their high tensile strength and wide
working temperature range, silica fibers exhibit no hysterisis or creep.33
The chemical properties of silica fibers allow them to be used in most
environments. Most elements do not react with silica fibers, however, some
molten metals such as magnesium, sodium, and silicon are exceptions as well as
hydrofluoric acid, fluorides, oxides, and hydroxides, the latter two
especially at elevated temperatures.32 Because of the chemical resistance
of silica fibers, common lubricants used in packings will not be absorbed into
the fibers (as is the case with asbestos fibers) but will instead be adsorbed
on the outside of the fibers. Silica fibers can be coated with common
elastomers including S.B.R., N.B.R., Hypalon®, Viton®, and Teflon.33
Uncoated silica fiber rope can be used where compact, dense, high
temperature seals are required such as in partial grooves in furnace oven
doors where the rope is not entirely contained.
Ceramic fibers—Ceramic fibers will not melt until temperatures exceed
1800°C (3272°F) and can withstand continuous working temperatures of up to
1427°C (2600°F) with short term use up to 1650°C (3000°F).27 The tensile
strength of ceramic fibers is in the 1.72 x 106 kPa (250,000 psi) range.
Even at 1093°C (2000°F) one brand of ceramic fiber tested (3M-Nextel)27
retained 100 percent of its tensile strength. Shrinkage and moisture
absorption are virtually nonexistant.27 Ceramic fibers retain their
flexibility and resiliency even at elevated temperatures-2"
The chemical properties of ceramic fibers, such as the Garlock product,
Thermo-Ceram™, allow them to be used in most environments. They are
resistant to most corrosive agents with the exception of hydrofluoric acid,
phosphoric acid, and hot concentrated alkalis.2®
Information is unavailable at this time to determine the compatibility of
ceramic fibers and common elastomers used in gasketing manufacture. Ceramic
can be coated with graphite for added lubricity and can be enclosed in wire
mesh for added strength.2^
Graphite fibers—Graphite fibers have the highest heat resistance of the
materials presently under consideration. Its tensile strength increases until
2200°C (4000°F), it is heat resistant above 2760°C (5000°F) and it will not
melt but will instead sublime at 3740°C (6700°F).29 One particular
packing2" produced by Garlock called Graph-Lock® withstands temperatures
200
-------
from -200°C (-328°F) to 500°C (932°F) in oxidizing media and temperatures up
to 3000°C (5432°F) in reducing or inert media. Graphite fibers also have
excellent resistance to temperature changes and, in addition to their wide
temperature range, graphite fibers have high tensile strength.3^ Even at
elevated or cryogenic temperatures, graphite fiber products do not exhibit
cold flow characteristics and do not soften, harden, or otherwise
degrade.->4 When added strength is needed in extremely high pressure
applications, mesh inserted sheet can be used. The mesh also helps prevent
damage during handling and installation. In addition, graphite has unique low
frictional characteristics of platelets, which help where motion is a
problem.^2
Graphite fibers have a high resistance to most agents including organic
and inorganic acids and bases, solvents, waxes, and oils. Exceptions are
strong oxidizing compounds such as concentrated nitric or sulfuric acids with
dissolved oxidizing salts, chromium (VI), permanganate solutions and
perchloric acid. In addition, graphite fibers are not resistant to molten
alkaline and alkaline earth metals. ^4
Graphite fibers, as a dry packing, have all the inherent lubricating
qualities of pure graphite.34 However, Teflon and other lubricants are
impregnated into the graphite packing to block potential leak paths.^0
Aramid fibers—Kevlar 29, an Aramid fiber, does not melt or support
combustion under normal environmental conditions but will carbonize at about
427°C (800°F). At temperatures as low as -46°C (-50°F), Kevlar 29 exhibits
essentially no embrittlement or degradation of fiber properties and it does
not sublime. The fiber exhibits virtually no shrinkage up to 160°C (320°F).
Kevlar 29 can be used as an asbestos substitute up to 204°C (400°F). The
tensile strength of Kevlar 29 fiber is temperature dependent but can attain
2.758 x 106 kPa (400,000 psi)(see Figure 2). Creep characteristics of
Kevlar 29 are equivalent to that of fiberglass but Kevlar 29 is much less
susceptible to creep rupture.^0
The chemical resistance of Kevlar 29 is excellent except for a few strong
acids including hydrochloric, hydrofluoric, nitric, and sulfuric (see Table
54). Its pH range is said to be between 3 and 11. However, compression of
Kevlar may increase friction, heat, and therefore wear, in turn increasing
degradation that may be caused by the presence of acid in such uses as A/C
pipe.37
Kevlar 29 has been coated with many elastomers and other materials.
These include:
• neoprene synthetic rubber,
• Hypalon synthetic rubber,
• synthetic rubber,
• nitrile rubber,
®
• Nordel hydrocarbon rubber,
201
-------
THE EFFECT OF TEMPERATURE ON
THE TENSILE STRENGTH OF
KEVLAR® 29 ARAMID
400
(2758)
350
(2413)
300
(2068) _
6
(5.3)
4
(3.5)
2
(18)
ASTM D2256
TESTED AT ROOM TEMPERATURE
200°C
"\
392°F
o
Q_
250
(1724)
200 5
(1380) -
150
(1034)
CO
100
(690)
50
(345)
100
200 300
TIME, HOURS
400
500
Figure 2. The Effect of Temperature on the Tensile Strength
of Kevlar® 29 Aramid30
202
-------
TABLE 54. CHEMICAL RESISTANCE OF YARN
OF KEVLAR® 29 ARAMID30
Environment Tensile strength
(100 hr* exposure at 70°F; 21°C) loss %
Acids
Formic (90%) 10
Hydrochloric (37%) 90
Hydrofluoric (10%) 12
Nitric (70%) 82
Sulfuric (70%) 100
Other Chemicals
Brake Fluid (312 hr) 2
Greases (moS2 and Lithium base) 0
Jet Fluid (JP-4) (300 hr) 0
Ozone (1000 hr) 0
Tap Water 0
Boiling Water 0
Superheated Water 156°C (313°F) 80 hr 16
* Except where noted.
203
-------
• Buna-N,
• urethane polymers,
• silicon and fluorosilicon,
f polyvinyl chloride,
• Teflon (TFE, FEP) fluorocarbon resin,
•( polyvinyl alcohol,
(R)
• Tedlar polyvinyl chloride, and
• Mylar*® polyester.
Teflon fibers—Teflon fibers soften at elevated temperatures and become
less ductile at subzero temperatures; however, working temperature limits
range from -268°C (-450°F) and 288°C (550°F). The fibers are most ductile and
flexible between -73°C (-100°F) and 288°C (550°F). The tensile strength of
Teflon fiber is dependent on temperature with maximum strength occurring at
21°C (72°F), or 3.59 x 105 kPa (52,000 psi).31
The unique molecular structure of Teflon fiber makes it inert to powerful
oxidizing agents and to such reagents as boiling sulfuric acid, fuming nitric
acid, and boiling sodium hydroxide. The only known solvents for Teflon fiber
are certain perfluorinated organic liquids at temperatures above 299°C
(570°F).31
Packing braided from bleached and specially impregnated and treated
Teflon is currently in use throughout the industry. Gasket tape, made from
the same bleached impregnated fiber as packing, is used for such applications
as head gaskets on glass lined reactors, pipe flanges, and top and bottom
gaskets on centrifuges. Because of the high mechanical strength and
resistance to cold flow of Teflon fiber, gasket tape made from Teflon fiber
resists extrusion at internal pressures as high as 1.4 x 10" kPa
(200 psi) .31
Product Substitutes
The number of potential gasket and packing materials that do not contain
asbestos is extremely large. One distributor /secondary manufacturer
(Excelsior, Inc.)^^ lists over 160 different raw materials that do not
contain asbestos (see Table 55). At least two manuf acturers^» ^ conduct
presentations for industry showing nonasbestos packing and gasket materials.
At least two manuf acturers' have already developed materials to
compete with asbestos gaskets. In addition, three other
manuf acturers^2>45,46 are developing alternatives but consider all their
information proprietary. For that reason, only those products already in
production will be described in this section.
204
-------
TABLE 55. NONASBESTOS RAW MATERIALS FOR GASKETS AND PACKINGS41*
Ar.copac
Acolatc
Alinnlmim
Aluminum foil
Armaflex
Artus shim
Asphalt-saturated sheathing felt
Backehp.ck felt
Baki'lite
Hinders board
Black fibre
Blotting paper
Bond paper
Bucar
Bucotc
Buna N-rubber
Buna S-rubber
Cambric
Canvas
Canvas-based bake-lite
Canvas-based phenolic
Cardboard
Celluloid
Cellulose materials
Cerafelt
Cerakotc
CoIcon
Chipboard
Chipboard-treated
Clear cellulose acetate
Clolh
Cloth-inserted rubber
Copper
Cork
Cork-rubber compositions
Cork-synthetic compositions
Crepe barrier paper
Deadening felt
DclrIn
Duck
IHirao.el
Diiriicnrk
Duroi.l
F.I'DM
F.l'T
KmbtiNsrd chipboard
F.mi-ry elm h
KthaCoam
l-'ahrir .supporti-il rubber
Fairprrnr materials
l-Vli
K MMV, vul can I xcd
VI ri'board
Vilnvf I.'X
I'ihcrc.lass
Vilir rc.l a:;s , ni'
-------
Nu-Board 180044'47—
Nu-Board 1800 is currently being manufactured by Janos Industrial
Insulation Corp. It is made of inorganic fiber and inert fiber suitably
bonded to provide a material having physical characteristics similar to
asbestos millboard.44
Nu-Bourd 1800 can withstand temperatures up to 982°C (1800°F) depending
upon application. The tensile strength of Nu-Board 1800 is 4902 kPa (711
psi). The chemical resistance of Nu-Board 1800 is still being tested,
however, it has been used as a filler in metal-clad gaskets. An important
advantage of Nu-Board 1800 over asbestos millboard is its capability of being
wet molded. Wet molding allows awkward shapes to be formed while wet and then
dried hack to hardness. When dried, molded Nu-Board 1800 can be coated with
ceramic cement enabling it to resist temperatures up to 1260°C (2300°F) and
more chemical attack. Table 56 lists the nominal physical properties of
Nu-Board 1800.48
Nu-Board 1800 was developed not only for a gasket material but also as an
insulation material. Table 57 lists some of the typical uses of Nu-Board
1800. Janos Industrial Insulation Corp., the manufacturer of Nu-Board 1800,
is developing and testing a new asbestos-free product designed to replace
compressed asbestos sheet. No information regarding its performance is
currently available.47
Ceramic, Victocor, and Solicor—21
These products from Dana Corp., Victor Products Division, are discussed
here, although some aspects of their manufacture would classify them as
"beater-add" in this report. Made of ceramics (Ceramic) or graphite
(Victocor, Solicor) they represent an effort by Victor to supply a product
which is directly interchangeable with asbestos gaskets. They are
competitively priced, have no current regulatory agency restrictions, and can
seal components that asbestos cannot—namely, exhaust applications. As
totally new products, their temperature resistance has been measured up to
1260°C (2300°F) and Victocor 289 which combines graphite, a steel core, and an
adhesive, has the benefits of mechanical and chemical bonding. Victor's hard
gaskets (the facings on these gaskets are made on paper-making—Fourdrinier—
machines) range from cylinder head and intake manifold applications, to
replacements for asbestos millboard. In one, a rubber bound facing material
is mechanically attached to a perforated steel core; others use neoprene or
nitrile bound facing materials. Victocor 809 is a totally new gasket
composition aimed at the 1980's engines. Soft gaskets and packings are also
produced—these require crush and extrusion resistance. Characteristics
include compatibilty with aluminum flanges; resistance to engine coolants,
fuels, lubricants, and oils; and torque retention properties.^1 The wide
variety of gaskets offered, including mechanical testing literature, verifies
the existence of many suitable substitutes to asbestos gaskets. Currently
asbestos-free versions of Victor's Victocor, Solicor, Victopac, Corbestos, and
Coramic materials are being sampled and tested by O.E. diesel and gasoline
manufacturers in the U.S. and abroad.22
206
-------
TABLE 56. NOMINAL PHYSICAL PROPERTIES OF NU-BOARD 180047
COLOR: BEIGE
DENSITY
TENSILE STRENGTH
FLEXURAL STRENGTH
COMPRESSION @ 300 psi
IGNITION LOSS
MOISTURE CONTENT
THERMAL CONDUCTIVITY
FLAMMABILITY
HEAT RESISTANCE
DIMENSIONS:
THICKNESS RANGE
SHEET SIZE
66.8 Ib/ft
711 lb/in
1280 lb/in
30-40%
20% max.
3%
0.0636 BTU/Hr-Ft-F°
WILL NOT BURN
UP TO 982°C DEPENDENT
UPON APPLICATION
INCLUSIVE 3/32" to 1/2"
40" X 40"
TABLE 57. TYPICAL USES OF NU-BOARD 180047
Lining furnances
Moving Pictures Booths
Elevator Shafts
Ceilings, Walls exposed
to heat
Gaskets
Stoves
Electric Ovens
Glass Lehr rolls
Float glass conveyor rolls
Cores for metal clad
door
Stove pad, welding
pads
Incinerators
Heater lining
Strongbox lining
Kiln lining
Molded for troughs
Cable protection
Gylon—49
Gylon gasketing materials, produced by Garlock, are fomulated by a
proprietary process that permits fluorocarbon particles to be restructured
with distinctive physical properties not found in Teflon. Three different
types of Gylon are produced, each with varied characteristics: Fawn, Blue,
and Black.49 Continuous working temperatures for Gylon range from -212°C
(-350°F) up to 260°C (500°F).
Gylon displays a resistance to creep, unlike Telfon resins. Gylon Blue
W;IK dovcvl.oped for low gasket loads such as in glass-lined pipe and reaction
vessels. Gylon Black is filled with graphite to resist hydrofluoric
acid.49 Table 58 compares gasketing characteristics of Gylon to both Teflon
and compressed asbestos, and also lists other physical properties of Gylon.
207
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TABLE 58. GYLON® PHYSICAL PROPERTIES49
Tensile Strength (PSI - Typical)
(ASTM F39-59)
Compressibility (% at 5000 PSI)
(ASTM F36-66)
Recovery (% Minimum)
(ASTM F36-66)
Creep relaxation (%) (ASTM F36-71)
Method B at 3000 PSI 1/8"
Elongation (%-Typical) (ASTM F39-59)
Modulus at 100% Elongation (PSI-Typical) (ASTM D1708)
Durometer (Shore D) (ASTM D2240)
NS
0 Specific Gravity (ASTM D792)
Dielectric Strength (V/MIL)(ASTM D149)
Volume Resistivity (OHM-CM) (ASTM D257)
(BTU-IN/HR/FT2/°F)
Thermal Conductivity (ASTM D2214)
Coefficient of Friction - Static (ASTM D1894)
Kinetic
Flammability
Bacterial Growth
35104
Fawn
2100
4-7
40
58
200
1600
65 ±5
2.1
500
2.0 x 101"
2.00
0.30
0.22
35120 35101
Blue Black PTFE
2200 3500 2100
18-20 4-7 5-7
42 50 34
70-1 70 80
300 300
1600 2400
58±5 65±5
1.62 2.16
305 *
2.6 x 1011 *
1.19 *
.19 0.22
.13 0.19
Will not burn
Will not support
Compressed
Asbestos
3000
7-17
40
57
—
—
—
—
--
—
~
— —
~
tTested at 1500 PSI
*Information available from supplier
-------
Preox (PAN)—
According to the 1980 EPA/CPSC "Substitutes to Asbestos Conference
Cnflkt'ts and Packings Roundtable Discussion, ^7 Celanese has just begun to
market a fiber called Preox (PAN) which is an intermediate material expected
to be commercially available in the near future. Preox is a precursor to a
carbon product. In carbon fiber production, the main cost factor is
apparently a 50 percent yield loss which is made lower with this intermediate
fiber product, thus reducing the initial production cost disadvantage.
However, installation costs are such that the cost of fiber production is
negligible. The fibers have over 10 percent elongation; they are based on
rayon precursors which have only a 20 to 30 percentyield, but with Preox,
Celanese uses the fiber itself (trade named Celiox ©) and therefore loses less
in the production process. PAN produces a 50 percent yield polyacrylonitrile.
Klingersil C-4400—
A premium compressed nonasbestos material for general purpose use. This
is composed of nitrile rubber bonded synthetic fibers and conforms to British
and American physical standards. Some types use a mild steel wire mesh
insert.50
Substitute Fiber Manufacturing Summary—
Manufacturing process—In the case of fiber-for-fiber replacements, the
same methods used for asbestos packing and gasket manufacture are used for
substitute fibers. A material such as DuPont's Kevlar is a pulp, produced in
a process similar to wood pulping, resulting in a slurry material with short
fibers of random length, amenable to use in wet or dry processes. Typical
beater-add applications are a natural for this material.^'
Substitute Product Manufacturing Summary—
Manufacturing process—In all cases,30,35 substitute materials are
manufactured by a proprietary process. All of the products manufactured by
Victor Products are listed in this Gaskets and Packings versus the Paper
Beater-Add section for continuity and because manufacturing process/material
involved in final product/end uses overlap (see Product Substitutes section).
Name and number of manufacturers—A complete list of manufacturers of
substitute products is impossible to determine at this time because, in many
cases, this development work is confidential. Manufacturers of substitutes
are unwilling to divulge this type of information for fear of losing their
competitive edge. Consequently, the following list of substitute
manufacturers is not exhaustive:
• Greene, Tweed and Co., North Wales, Pennsylvania
• Garlock, Inc., Palmyra, New York
g Janos Industrial Insulation Corp., Moonachie, New Jersey
• E. I. DuPont de Nemours & Co., Inc. Wilmington, Delaware
209
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• Norton Company, Sealants Division, Granville New York
• Boise Cascade, Specialty Paperboard Division, Beaver Falls, New York
• Victor Products Division, Dana Corp., Lisle, Illinois
• Celanese Corporation, New York, New York
• Celotex Corporation, Tampa, Florida-*!
• Richard Klinger, Ltd.
Production volumes—Information on specific production volumes for
substitute products listed in this report is not available at this time.
COST COMPARISON
For a fiber-for-fiber replacement, the cost of packings and gaskets is
proportional to the cost of fibers as the manufacturing processes are
identical. This assumes that the asbestos substitute gasket has been
correctly selected for the specific application and will not prematurely fail
because of a reaction between the fluid being contained and the gasket
material. Otherwise, gasket life for substitutes is equivalent to that of
asbestos gaskets. This service life may extend up to several years, or until
the gasket is replaced during periodic maintenance or equipment overhaul. See
Table 59 for a cost comparison of various fibers; Table 60 shows a cost
comparison of asbestos sheet for gaskets and gasket sheet manufactured from
various substitutes.
TABLE 59. COST COMPARISON BETWEEN ASBESTOS FIBERS AND SUBSTITUTES
(1976 DOLLARS)8.35
Fiber
Approximate cost $/lb ($/kg)
Asbestos fiber
Glass fiber
Nomex - fiber
- continuous filament
Kevlar
Teflon
Kynol
Carbon
Ceramics - 3M
1.00 (2.20)
0.75 (1.65)
5.00-5.50 (11.00-12.00)
6.50-10.00 (14.30-22.00)
5.50-6.00 (12.00-13.20)
7.00-10.00 (15.40-22.00)
3.60 (8.00)
2.00 (4.40)
30.00-32.00 (66.00-70.50)
210
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TABLE 60. COSTS OF ASBESTOS AND SUBSTITUTE GASKETING4»A4
Cost/sq ft 1/16" diam,
Material $ (m2)
Asbestos Sheet Garlock 900 1.96 (6.43)
Asbestos Sheet Garlock 7006 1.17 (3.85)
Gylon®Fawn 8.61 (28.25)
Vegetable Fiber Garlock 681 0.51 (1.65)
Cork 0.53 (1.75)
Red Rubber 0.37 (1.20)
Nu-Board 1800 0.87 (2.85)
These tables show that the cost of Teflon fiber is approximately 7 to 10
times that of asbestos. Graphite (carbon) fibers cost approximately twice as
much as asbestos and ceramic fiber prices vary greatly, from approximately 9
to 32 times that of asbestos. Gylon ranges from 4 to 7 times the cost of
compressed asbestos sheet, and Kevlar 29 is also in this range at 5.5 to 6
times the cost of asbestos-^5 Nu—Board costs consistently less than
asbestos sheet at approximately one-half to three-quarters the price of
asbestos. Price information on Victor Product's gaskets was not available,
however, literature reports that the current price structure is considered
attractive.^^
Of note here is that in many cases, the cost of the gasket or packing is
insignificant compared to the cost of its installation.4 Consequently, it
is often more cost effective to install a higher quality and associated higher
cost material rather than the lower cost-lower quality material. Lost
production while equipment is down because of gasket replacement must also be
included in the cost of the replacement.
In general, compressed asbestos sheet gasketing can be replaced with
substitute materials at this time with little added expense to the customer
unless the application is over 260°C.3 Graphite and sheet metal gaskets can
replace asbestos over 260°C, but their costs will constitute a major
expenditure (5 to 7 times the price of compressed asbestos) plus additional
plant maintenance. Rogers produces high temperature grades which have been
tested up to 425°C (800°F) and yield results equal to and in some cases,
better than, compressed asbestos. These grades, however, are sold at
approximately 1.75 the price of asbestos.38
Specific to packings; it appears that substitute materials are both
economically and physically a viable alternative to asbestos in every
application. Since substitute materials result in less abrasion on rotating
shafts and improved heat dissipaton, lower operating and maintenance costs are
experienced. As a result, the new synthetic packings are cost competitive
with asbestos packings. Table 61 shows the costs of various packing materials.
211
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TABLE 61. COST OF VARIOUS PACKINGS^
Material
Graphited white asbestos
Graphited blue asbestos
Flax, plain or graphited
Flax, TFE-impregnated
White asbestos, TFE-impregnated
Blue asbestos, TFE-impregnated
TFE filament yarn
Kevlar, TFE-impregnated
Carbon/graphite filament yarn
Suggested resale
$/lb to
consumer ($/kg)
8.57-17.27
(19.00-38.00)
21.22
(46.75)
7.34-9.52
(16.20-21.00)
11.15
(24.50)
16.66-17.95
(36.75-39.50)
26.72
(59.00)
45.56
(100.00)
28.42
(62.65)
51.68-161.16
(114.00-355.00)
$/lin. ft.
(meter)
1.34-3.45
(4.40-11.30)
3.45
(11.30)
0.87-1.29
(2.85-4.25)
1.34
(4.40)
2.49-2.79
(8.20-9.15)
4.61
(15.15)
8.29-9.49
(27.20-31.15)
4.24
(13.90)
7.38-18.52
(24.20-60.75)
CURRENT TRENDS
At least six manufacturers^'21,42,45,46,47 of gaskets and packings are
currently marketing or developing alternative products. Two manufacturers/
distributors^'^ conduct seminars for industry to present alternative
materials.
212
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Many gaskets are produced to meet military specifications. To a large
extent, these specifications are composition standards in addition to
performance standards. At this time, consequently, curtain quantities of
aHl>e.sLot) are required regardless of the performance oL the alternatives.
Without change in specifications, manufacturers are required to use asbestos
in many of their products.
Nonasbestos packings provide superior life characteristics and lower
friction and abrasion qualities than does asbestos.-^ It appears that the
major obstacle in completely eliminating asbestos from packings is the
resistance which sales and engineering people have to changing over to
nonasbestos packings. This resistance to substitute usage may be a result of
ignorance concerning the overall operating costs of utilizing asbestos
packings.
It is perhaps interesting to consider the new options companies now have
in purchasing nonasbestos gaskets and packings, by considering data from one
of the producers of these materials—Victor Products. A description listing
for their asbestos-free materials covers over 30 products, most of which can
be used directly in replacing such asbestos products as Corbestos, Asbestopac,
and other Victor materials.^2 Victor, in fact, has developed three classes
of asbestos-free gasket materials: exhaust system gaskets (for high heat
resistance), hard gaskets (strengthened with steel for applications such as
cylinder head and intake manifold sealing), and soft gaskets (for general
sealing with excellent crush-extrusion resistance)." Although many grades
are direct replacements for current asbestos-containing materials as
mentioned, others are new asbestos-free grades designed to fill other needs.
Mechanical test data supplied^ indicates equal performance (nonasbestos
versus asbestos) in actual applications of operation on test engines. A
record of over 300,000 miles of actual operation on field test vehicles for
asbestos-free cylinder head gaskets shows no major functional problems.55
In addition, specific customer switch-over trends are reported by
Victor,53,56 an indication that consumer knowledge in the area of
substitutes is increasing.
As a result of current industry programs, it has been predicted that
certain substitutes will take hold in the following established gasket
applications:^2
Application Nonasbestos Replacement Material
Exhaust systems and Graphite, ceramic fibers and fillers, and mica,
turbochargers combined with stainless steel substrates
Cylinder head and Organic fibers and binder, inorganic fillers form-
Intake manifolds ed by paper-making processes and combined with
metal substrates
High load/high Rubber-coated steel, cellulose fibers elastomeric
extrusion binders, glass fiber with fillers and elastomeric
binders, densified organic fibers and fillers
with elastomeric binders, and liquid systems such
as RTVs and anaerobics.
213
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Embossed steel or aluminum with high temperature coatings is expected to
continue use where engine structure permits.^^
CONCLUSION
One of the greatest advantages of asbestos is its versatility coupled
with low cost. As asbestos is so versatile, substitution requires diversified
product lines. For this product category, a practically endless list of
potential substitutes is available. In fact, in packing materials, the new
synthetic materials are preferable to asbestos in capabilities they exhibit.
In gasket applications over 260°C, asbestos appears to have advantages
(principally lower costs) over substitute materials. Graphite and metal
gaskets and others produced by Rogers (up to 425°C) can replace asbestos over
260°C, but their costs are somewhat prohibitive. In applications under 260°C,
there are a variety of substitutes which can replace asbestos with little
added expense to the user. In addition, many fibers are available but have
yet to be tried because of the present lower cost of asbestos.
In general, asbestos represents a familiar, time-tested fiber for use in
gaskets and packings which companies have subsequently designed into many
products. The asbestos easily met heat resistance, resiliency, and strength
requirements as well as being chemically inert. However, as manufacturers
have initiated research on potential substitutes, they have discovered not
only a wealth of potential materials that are suitable for this use, but that
they also possess qualities that are usually equal to or sometimes even better
than the old asbestos product. For packings, the new synthetics not only have
the capacity for replacing asbestos, but also can be applied in every
application and will require less housekeeping and monitoring procedures, now
required for asbestos.^ For gaskets, again, the replacement materials exist
such that compressed asbestos sheet use could be curtailed, with little added
expense to the consumer unless the application is over 260°C. Between 260°C
and 538°C, cost effective solutions are still being sought, although materials
such as graphite and silica are available.^ in addition to replacement
material development, asbestos-free gasket materials which are truly new in
the sense of not being a specific substitute for older asbestos-containing
materials have been developed in this area. Examples include the
high-temperature graphite sheet materials and ceramic fiber compositions.^3
As the replacement or service phase of the gasket business is the dominant
area, it is important to note that nonasbestos substitutes have been developed
for many of these applications, while in addition, new products have been
developed for new niches. The use of asbestos-free gasket materials is not a
new phenomenon in itself; rubber, saturated and unsaturated paper, felts,
embossed metals, and cellulose fibers have been used effectively for years in
sealing applications.-*' One of the most important new developments in
mechanical gasketing applications has been support rendered to a rubber-fiber
facing by a metallic core. Fibers can be asbestos or nonasbestos. The facing
may be compressed or beater-add. ->° Developments such as this, along with
new substitute products have increased attention on the gasketing field by
many consumers.
214
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In summary, although asbestos currently is present in the majority of
U.S. gaskets (often these products have been 80 percent asbestos, with added
polymer binder systems and fillers), there are disadvantages to asbestos.
These include scarcity in the U.S. (most is imported), especially for longer
grades (A and 5 for example) which are the lengths used in gasket materials
and which have been in tight supply for the past A years. In addition,
asbestos does not always solve all of the problems being asked of it—often
better heat resistance, scalability, and crush resistance are required. For
years gasket material producers and designers have attempted to improve the
binder system in gaskets; now they look to the other 80 percent of the gasket
which represents a fiber. As in the other categories covered here, no one
manmade fiber or other high temperature material approaches asbestos in its
critical physical properties, but blends of other fibers and fillers discussed
here have been successful. It is also reported that some companies have
eliminated not only asbestos, but gaskets in general, from their current
assemblies, replacing them with liquid sealant to reduce tolerances required
for assembly. 2
215
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REFERENCES
1. Johns-Manville Corporation. Sealing Components, Comprehensive Guide to
Mechanical Packings, Ropes & Tapes. PK-401. Ken-Caryl Ranch, Denver,
Colorado. April 1978. 65 pages.
2. Meylan, W. M., et al. Chemical Market Input/Output Analysis of Selected
Chemical Substances to Assess Sources of Environmental Contamination:
Task Ill-Asbestos. EPA 560/6-78-005. August 1978.
3. Koehler, Stephen D., Greene, Tweed & Co. Gaskets and Packings. Speech
given at EPA/CPSC Conference on Substitutes to Asbestos, July 14-16,
Arlington, VA, 1980.
4. Swanson, R. C., Sales Rpresentative, Colt Industries, Garlock, Inc.
Mechanical Packing Division, Charlotte, NC. Meeting with Mr. T. Curtin,
GCA Corporation, February 21, 1980.
5. Johns-Manvllle Corporation. Sealing Components, All You Need to Know
about Gasket Materials. PK-132. Ken-Caryl Ranch, Denver, Colorado.
November 1979. 17 pages.
6. Armstrong, Industry Products Division Accobest®, Accopac®, Armstrong
Gasket Material Specifications. IP-926-175x. Lancaster, Pennsylvania.
5 pages.
7. Clifton, R. A. Preprint from 1980 Bureau of Mines Minerals Yearbook.
Asbestos, p. 4.
8. Arthur D. Little of Canada and Sores, Inc. Characterization of the U.S.
Asbestos Paper Markets. Report to the Government du Quebec, Ministere de
1'Industrie et du Commerce. May 1976.
9. Telecon. Mr. Ambursal, Armstrong Cork Co., Lancaster, PA, (717)
397-0611, with Anne Duffy, GCA Corporation, GCA/Technology Division,
April 16, 1981, Call #20.
10. Telecon. Sales Representative, Detroit Gasket and Mfg. Co., Detroit, MI,
(313) 968-2200, with Anne Duffy, GCA Corporation, GCA/Technology
Division, April 16, 1981, Call #21.
11. Telecon. Company Representative. Fitzgerald Gasket, Torrington, CT,
(203) 482-9366, with Anne Duffy, GCA Corporation, GCA/Technology
Division, May 4, 1981, Call #37.
12. Telecon. Harvey Loud's Office, GAF Corp., New York, NY, (212) 621-5000,
with Anne Duffy, GCA Corporation, GCA/Technology Division, April 13,
1981, Call #1.
216
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13. Telecon, Mr. McDoughall, Hollingsworth and Vose, East Walpole, MA, (617)
668-0295, with Anne Duffy, GCA Corporation, GCA/Technology Division,
April 16, 1981, Call #22.
14. Telecon. Company Representative. Janak Inc., Weatherford, TX, (817)
549-8771, with Anne Duffy, GCA Corporation, GCA/Technology Division, May
4, 1981, Call #38.
15. Telecon. Raymond Croucheck, Lament Metal Gasket Co., Inc., Houston, TX,
(713) 222-0287, with Anne Duffy, GCA Corporation, GCA/Technology
Division, May 4, 1981, Call #39.
16. Telecon. Company Representative. Parker Seal Gaskets, North Brunswick,
NJ, (201) 247-6800, with Anne Duffy, GCA Corporation, GCA/Technology
Division, May 4, 1981, Call #40.
17. Telecon. Company Representative, Sacomo-Sierra, Carson City, NV (702)
882-7560, with Anne Duffy, GCA Corporation, GCA/Technology Division,
April 17, 1981, Call #23.
18. Telecon. Company Representative, Standee Rubber Gaskets, Houston, TX
(713) 944-3160, with Anne Duffy, GCA Corporation, GCA/Technology
Division, May 4, 1981, Call #42.
19. Telecon. Tony Rokos, Amatex, with Anne Duffy, GCA Corporation,
GCA/Technology Division, May 4, 1981, Call #36.
20. U.S. Bureau of Mines, Mineral Industry Surveys, Asbestos in 1978, by R.
A. Clifton, August 22, 1979.
21. Information from Victor Products Division, Dana Corporation; Exhibit 1 of
October 21, 1981 letter and enclosures to Mr. Larry Dorsey, U.S. EPA,
from John E. Zeitz, Division Chief Engineer, Victor Products Div. of Dana
Corp., 1945 Ohio St., Lisle, IL.
22. Article in Diesel & Gas Turbine Progress magazine, What Will Replace
Asbestos Gaskets?, by John E. Zeitz, July 1980; included as Exhibit 12 of
Reference 21.
23. Newtex Industries, Inc. Zetex. All of the Protection But None of the
Health Hazards of Asbestos. Victor, New York. 4 pages.
24. Colt Industries, Garlock, Inc., Mechanical Packing Division, Industrial
Packing. Thermosil Textured Fiberglass Cloth, Tape, Tubing. A
Nonasbestos Product. LX-7/79-10M. Palmyra, NY, July 1979. 7 pages.
25. Armco, Hitco Materials Division. Refrasil Insulation Textiles Can Take
this Testl Can Yours? LHT/MD-10079 10MCP 11-79. Gardena, CA.
217
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26. Colt Industries, Garlock, Inc., Mechanical Packing Division, Compression
Packing. Thermo-Ceram®. CMP-121. Sodus, NY, February 1979. 2 pages.
27. Ceramic Fiber Products/3M. Nextel® 312 Ceramic Fiber from.3M. N-MHFOL
(79.5) MP, St. Paul, MN. 4 pages.
28. Colt Industries, Garlock, Inc., Mechanical Packing Division. Nonasbestos
Packings, Gasketing, Dynamic Seals, Expansion Joints, Oil Seals,
Fiberglass Cloth. MP-902. Palmyra, NY. August 1979. 9 pages.
29. Armco. Hitco Materials Division. Hitco Aerospace Materials.
LHT/MD-3278 3M TC 9-78. Gardena, CA. September 1978. 5 pages.
30. E. I. DuPont de Nemours & Co., Inc. Textile Fibers Department.
Characteristics and Uses of Kevlar 29 Aramid Number 375. Wilmington,
DE. September 28, 1976. 7 pages.
31. E. I. DuPont de Nemours & Co., Inc. Properties, Processing and
Applications of Teflon TFE Fluorocarbon Fiber. Bulletin TF-2,
Wilmington, DE. May 1978. 15 pages.
32. Armco. Hitco Materials Division. Refrasil Refractory Silica in Textile
Form Insulation, Technical Data Bulletin Engineering Data. P.O.
LHT/MD-3979 R 10M CP 10-79. Gardena, CA. October 1979. 4 pages.
33. Armco. Hitco Materials Division, Refrasil Refractory Silica in Textile
Form Insulation Product Data Bulletin All Products. P.O. LHT/MD-1779 15
M CP 11-79. Gardena, CA. November 1979. 4 pages.
34. Colt Industries, Garlock, Inc., Mechanical Packing Division, Compression
Packing. Graph-lock® Graphite Packing. CMP-123. Sodus, NY. 3 pages.
35. Chiostergi, R., Marketing Manager, E. I. DuPont de Nemours & Co., Inc.,
Wilmington, DE, (302) 999-3951, Personal Communication with Mr.
Henderson, GCA/Technology Division, February 1, 1980. Notebook #07,
Phone Call #20.
36. The Chemical Rubber Co., Handbook of Tables for Applied Engineering
Science. Cleveland, Ohio. March 1970. Page 122.
37. Gaskets and Packing Roundtable Discussion, Substitutes for Asbestos
Conference, U.S. EPA/CPSC, Arlington, VA, July 14-16 1980.
38. Letter from Robert F. Lee, Manager, Envir. Engineering, Rogers Corp.,
Rogers, CT, to Mr. Larry Longanecker, U.S. EPA, September 8, 1981.
39. The Chemical Rubber Co. Handbook of Tables for Applied Engineering
Science. Cleveland, OH. March 1979. Page 122.
218
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40. Greene, Tweed & Co. Palmetto® Packings, Tephite Style 1387. North
Wales, Pennsylvania. 1979. 2 pages.
41. Excelsior, Inc. Advertising List of Raw Materials Publication No.
49758. Rockford, Illinois. 1 page.
42. Koehler, S., Product Manager, Greene, Tweed & Co., North Wales,
Pennsylvania, (215) 256-9521, Personal Communication with Mr. Curtin,
GCA/Technology Division, February 22, 1980. Notebook #06, Phone Call #40.
43. AIA comments to GCA Draft Final Substitutes Report, received 10/22/81.
44. Connolly, T., Janos Industrial Insulation Corp., Moonachie, NJ, (201)
933-5854. Personal Communication with Mr. Curtin, GCA/Technology
Division, February 27, 1980. Notebook #06, Phone Call #42.
45. Pafsarella, M., Laboratory Director, F. D. Farnham Co., Necedah,
Wisconsin, (608) 565-2241. Personal Communication with Mr. Curtin,
GCA/Technology Division, February 11, 1980, Notebook #06, Phone Call #22.
46. Call, M., Product Development Manager, Boise Cascade Specialty
Paperboard Division, Beaver Falls, NY, (315) 346-6111. Personal
Communication with Mr. Curtin, GCA/Technology Division.
47. Letter and attachments from Connolly, T. J., Janos Industrial Insulation
Corp., to T. Curtin, GCA/Technology Division, February 21, 1980,
Information on asbestos substitutes.
48. Janos Industrial Insulation Corp. Nu-Board 1800. The Asbestos Millboard
Replacement. Moonachie, New Jersey.
49. Colt Industries, Garlock, Inc., Mechanical Packing Division, Industrial
Packing. Gylon. GSK-292. Palmyra, NY, January 1980.
50. Information from Richard Klinger, Ltd., supplied in Reference 21 letter.
51. Telecon. Company Representative, Celotex Corp., Tampa, FL, (813)
871-4811, with Anne Duffy, GCA Corporation, GCA/Technology Division,
April 13, 1981, Call #3.
52. Reference 21, Exhibit #2.
53. Zeitz letter of Reference 21.
54. Reference 21, Exhibit #6.
55. Reference 21, Exhibit #7.
219
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56. Caterpillar Tractor Company information supplied as Exhibit //8 of
Reference 21.
57. Zeitz, J. E., J. A. Damusis, and J. A. Ulrich, Victor Products Div. Dana
Corp. Designing with the New Asbestos-Free Gasket Materials. Presented
at the International Congress and Exposition, Detroit, MI, February
23-27, 1981. SAE Paper #810366; included as Exhibit #4 of Reference 21.
58. Czernik, Daniel E., Fel-Pro, Inc./Felt Products Manufacturing Co., Recent
Developments and New Approaches in Mechanical and Chemical Gasketing.
Presented at the International Congress and Exposition, Detroit, MI,
February 23-27, 1981. SAE Paper # 810367.
220
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SECTION 8
PAINTS, COATINGS, AND SEALANTS
ASBESTOS PRODUCT
Special Qualities
Various types of paints, protective coatings, and sealants containing
asbestos fibers are considered in this section including:
• Sealants
• Roofing coatings and roofing cements
• Automobile and truck undercoating
0 Linings and coatings (nonasphalt)
• Texture paints
• Spackle and dry wall joint compounds
Sealants may be defined as liquid or semi-liquid fillers used to fill
gaps in buildings and equipment construction. Coatings are covering products
used to rejuvenate and/or protect various types of surfaces. Major
manufacturers have indicated that asbestos is no longer used in texture
paints, spackle and dry wall joint compounds; however, asbestos may still be
present in many older installations.
Asbestos is used as a filler and reinforcement agent in diverse products
to impart the following characteristics:
• Strength and durability
• Corrosion resistance - protection from weather, ultra-violet rays as
well as water proofing
« Decay, vermin, and thermal resistance
a Sound deadening
221
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• Stability prevents slump and flow on sloped or vertical surfaces
• Economy
• Viscosity and consistency
These characteristics are provided by the unique properties of chrysotile
listed in Table 62. The affinity shown by asbestos for asphalt and the
ability to control viscosity make it indispensable for asphalt based
products. Viscosity control is essential fcr waterproofing. Without
asbestos, asphalt compounds flow, leaving gaps that allow water to penetrate.
Asbestos also provides excellent resistance to weathering, which is essential
for outdoor sealant uses. The ability to bridge cracks and the fact that
asbestos is available in various fiber lengths are important in joint compound
and texture paint applications.
TABLE 62. UNIQUE PROPERTIES OF CHRYSOTILE ASBESTOS
Property
Comment
Alkali resistance
Fine fiber diameter
High tensile strength
High impact resistance
Temperature resistance
Surface charge
Fibrous form
Inorganic origin
Cost
Attack only occurs at extremely high concentrations
and temperatures.
Provides many reinforcing fibers per unit weight.
2,068,500 kPa to 3,447,500 kPa
Not brittle at high temperatures; temperature at
maximum ignition loss - 982°C
Good; brittle at high temperatures; temperature at
maximum ignition loss - 982°C
Positive - provides chemical bond to many media,
especially asphalt.
Provides desired viscosity characteristics.
Not subject to attack by vermin.
Provides low cost/performance or cost/physical
property ratio.
Information from non-published document on Asbestos Dust done for OSHA, 1978.
222
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Product Composition
A total of 10,900 metric tons of asbestos were consumed for this category
in 1980, down from 19,100 metric tons in 1978.*>2 Most asbestos used in
roofing products is Grade 7 (shortest fiber length) chrysotile.'- Over 90
percent of the asbestos used for the remaining paints, coatings, and sealants
in this category is also Grade 7 chrysotile.^ Approximately 98 percent of
milled asbestos is Canadian.
The bulk of sealants are asphalt-based and contain 5 to 30 percent
asbestos and 55 to 80 percent asphalt cut with up to 50 percent naphtha,
mineral spirits or petroleum solvents to achieve the consistency appropriate
for the desired use. Other ingredients include rust-proofing chemicals,
pigments, powdered aluminum and other metals for heat reflectance and
appearance, plaster of paris in spackle and dry wall joint compounds,
insulating materials such as cork, emulsifiers, and resins, and miscellaneous
fillers such as clay, barite, etc. The asbestos fibers are thought to be
completely encapsulated in all of the products included in this category.
Roofing materials consist of coatings and cements containing 5 to 6
percent and 9 to 10 percent asbestos, respectively.^ Both contain greater
than 70 percent asphalt and are thinned to the desired consistency with
naphtha, mineral spirits, or petroleum solvents.
Texture paints consist of a small amount of asbestos (less than 1
percent)^ combined with various pigments and fillers.
For automotive and truck underlinings, the quantity of asbestos used in
production may vary widely due to the rudimentary manufacturing process."
Uses and Applications
Asbestos is normally used in asphalt and tar bases for such products as
roof sealants, waterproof coatings, and automobile undercoatings. It has also
been used in plaster of paris bases for spackle and dry wall joint compounds.
Table 63 lists all uses of asbestos in the sealants category and the
characteristics that make asbestos desirable here.
The primary use of asbestos is in roofing materials. Coatings are
brushed or sprayed on and cements are trowelled on. Another important use of
asphalt-based compounds is in automobile and truck undercoatings. Other
asphalt-based compounds for waterproofing applications are listed in Table 63.
The remaining uses listed in Table 63 consume minor amounts of asbestos
and in some cases no longer use asbestos. In 1977, the Consumer Products
Safety Commission banned the use of asbestos in spackling and dry wall joint
compounds.' Until then, nearly all of these products contained asbestos as
a reinforcing agent. The use of asbestos in tennis court coverings and
blacktop sealants has been cited in the literature, but the high viscosity
imparted to these products by asbestos would inhibit sealant flowage into
cracks and holes, which is a necessary property in these applications.^
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TABLE 63. ASBESTOS USES IN THE SEALANTS CATEGORY3
Use
Distinguishing
characteristics
of asbestos"3
Roof coatings
Roof cements
Flashing cements
Chimney stack paints
Automobile and truck undercoatings
Appliance insulating coatings
Corrosion-resistant coatings (resistant to salt
solutions including seawater spray, organic acids,
mineral acids, petroleum products)
Waterproof coatings for underground pipelines,
concrete foundations, side walls, tanks, and other
structures such as mobile homes and cooling towers
in nuclear power plants
Anticondensation coatings for low temperature
refrigeration services
Tile cements
Woodblock and concrete floor mastics
Spackle
Dry wall joint compounds
Caulking compounds
Texture paints
Sprayed-on ceiling finishes
Welding rod coatings
A, E, G
A, G
A, G
B, E, G
A, B, E, F, G
E, F
B, G
A, C, E, G
B, G
A
F, G
A, C, D
A, C, D
A, C, D
A, C, D
A, C, D
B, E
aCompiled by GCA Corporation during research on sealants; including
phone calls listed in notebook 1-619-007-02, 1980.
bLetters correspond with the characteristics listed below. Stability,
durability, and economy of asbestos are relevant to all uses listed
above.
Key: A. Strength
B. Corrosion resistance
C. Decay resistance
D. Vermin resistance
E. Thermal resistance
F. Sound deadening
G. Waterproofing
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Although asbestos may still be used in a number of minor products, many
manufacturers are no longer including asbestos in their formulae. None of the
welding rod or cement distributors contacted were familiar with currently
manufactured products containing asbestos.°~H Small amounts of asbestos
(approximately 1 percent) can be added to texture paints to provide texture
and crack-bridging abilities. None of the texture paint manufacturers
contacted precently use asbestos in their formulae.12-15
Product Manufacturing Summary
Production processes for sealants, coatings and paints are essentially
the same. All three categories are therefore grouped as "sealant products" in
this manufacturing process description.
Manufacturing Process—
Small manufacturing plants consist of one production line for all sealant
products. Large plants producing a wide variety of products may have several
production lines, each of which is designed for a specific product.
Production facilities for all sealants are essentially the same. Operations
are normally part time, especially for minor products with low market
requirements. One major manufacturer (Armstrong Cork) of roof coating
emulsions and joint insulation compounds stated that asbestos emulsions for
roof coating are made 5 days per week in a one-or-two shift operation. °
Other facilities are used less frequently to manufacture joint insulation.
Because of seasonal fluctuation in demand, the process generally operates one
shift from November through March and two shifts the rest of the year.
Sealants are produced by batch processes. Basically, the fiber is
introduced, fluffed, put in a batch mixing tank, mixed with asphalt or tar and
solvents or other additives as required for an even dispersion, pumped to
packaging (containerizing) operations, and finally shipped out to market.
First, pallets of bagged asbestos are moved from a shipping or storage
area to a staging area where the appropriate quantity is weighed out, and then
dumped either directly into a hopper or into a fluffing machine. This machine
is used to separate the compressed fibers facilitating dispersion and
encapsulation during asphalt mixing. Typically, fluffed asbestos fiber is
transferred to hoppers or directly to a batch mixing tank, ' where they are
mixed with other dry ingredients and the asphalt and solvents, as required.
Mixing proceeds until the material is evenly dispersed. When a batch is
finished, the material is pumped to the packaging (containerizing) operation
and placed in appropriate sized containers. The predominant container for
coatings is 5-gallon metal pails with sealed lids. Special orders may use
drum containers. Bulk shipments in tank cars may take place, but are
infrequent.
The batch sizes vary from several hundred gallons for small manufacturers
with one production line to several thousand gallons for large manufacturers
with several production lines oriented to specific products. ' Batch sizes
vary with size of company, type of product, method of containerization, type
of existing equipment, and size of order. Sealant products are shipped out
ready for distribution and use; therefore, there are no secondary fabricators.
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Name and Number of Manufacturers—
Listed in Table 64 are the national manufacturers of asbestos sealant
products.
Production Volumes—
Sealants consumed approximately 10,900 metric tons of asbestos or 3
percent of all asbestos used in the United States during 1980, according to
the Bureau of Mines.^ Asbestos Magazine estimated that 29,000 metric tons
(32,000 tons) of asbestos or 5 percent of the United States total was consumed
by the sealants category in 1978.^ The value of asbestos consumed in 1978,
calculated from Bureau of Mines consumption data and current asbestos prices,
is $3.2 million. An expenditure of $3.2 million represents 1.6 percent of
total annual sales for sealants, which amounts to approximately $200
million. '
SUBSTITUTE PRODUCTS
Methodology
Search Strategy—
The major national trade associations related to paints, coatings, and
sealants were contacted regarding asbestos products and substitute products.
Mr. Edward Fenner of Johns-Manville was given as a reference and subsequently
contacted. He provided an excellent framework for the information provided in
this section. The 20 largest United States asbestos product manufacturers as
listed by Meylan^° and various sources in the literature were investigated.
Summary of Contacts—
The following individuals and organizations provided useful information
regarding paints, coatings, and sealants.
• Mr. Robert Pigg
Asbestos Information Association of North America
1745 Jefferson-Davis Highway
Arlington, VA 22202
• Mr. Edmund Fenner, Director of Environmental Services
Johns-Manville Corporation
Ken-Caryl Ranch
Denver, CO 80217
• Company Representative
International Slurry Seal Association
Suite 700
1101 Connecticut Avenue NW
Washington, DC 20005
• Mr. Ken Brzozowski
TREMCO Incorporated
10701 Shaker Boulevard
Cleveland, OH 44104
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TABLE 64. NATIONAL MANUFACTURERS OF ASBESTOS
SEALANT PRODUCTS18'19
Manufacturer
Plant location
Product
Celotex Corporation
(A Division of Jim
Walters Corporation)*
GAF Corporation
Gibson Romans Co.
Lockland, OH
Houston, TX
Memph i ?, TN
Millis, MA
S. Bound Brook, NJ
Cleveland, OH**
Roofing products
Roofing products
Roofing products
Roofing products
Roofing products
Roofing products
Johns-Manville
Koppers
Monsey Products Co.+
Waukegan, IL
Manville, NJ
Savannah , GA
Marrero, LA
Los Angeles, CA
Fort Worth, TX
Pittsburg, PA
Youngs town, OH
Wickliffe, OH
East Rutherford, NJ
Garland, TX
Kimberton, PA
Rock Hill, SC
Troy, NY
Roofing products
Roofing products
Roofing products
Roofing products
Roofing products
Roofing products
Roofing products
Roofing products
Roofing products
Roofing products
Roofing products
Roofing products
Roofing products
Roofing products
"ie
Sealants were produced in New Jersey in the past but this has
been discontinued.20
''^Corporate headquarters; other branches throughout the U.S.
+Telecon with manufacturer.
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Mr. William Pass, Lab Technician
Synkoloid Company
400-T Colgate Drive
Atlanta, GA 30336
Mr. Eugene Connor, National Sales Manager
Johns-Manville Corporation
Ken-Caryl Ranch
Denver, CO 80217
Mr. Fred Ma Hay, Sales and Marketing
Consolidated Protective Coatings Corporation
1801 E. 9th Street, Suite 202
Cleveland, OH 44114
Mr. Jack Fleming, Treasurer
Bondex International
2682 Pearl Road
Medina, OH 44256
Company Representative
Igo's Welding Supply Company
71 Arlington Street
Watertown, MA 02172
Mr. Colin Hemms, Marketing Manager for Roof Maintenance Products
Koppers Corporation
1050 Koppers Building
Pittsburgh, PA 15219
Mr. David L. Hall, Marketing and Technical Coordination
Fiber Materials Incorporated
Biddeford Industrial Park
Biddeford, ME 04005
Ray Connor, Director of Technical Division
National Paint and Coatings Association
1500 Rhode Island Avenue NW
Washington, DC 20005
Charles Spector, Vice President
Everseal Manufacturing Company, Incorporated
477 Broad Avenue
Ridgefield, NJ 07657
Harry Schwartz, Assistant Technical Director
Dutch Boy Paints - Baltimore Paint and Coatings Group
2325 Hollis Ferry Road
Baltimore, MD 21230
228
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• Jack H. Engel, Manager of Rubber and Plastics Lab
Chrysler Corporation, Chemical Division
5455 W. Jefferson Street
Trenton, MI 48183
• Ken Heffner, President
Electro Chemical Engineering and Manufacturing Company
Acid Proof Lane
Emmaus, PA 18049
• Sika Chemical Corporation
P.O. Box 297 T
Lyndhurst, NJ 07071
• Tom Dudick, President
Dudick Corrosion-Proof Manufacturers, Incorporated
578 E. Highland Road
Macedonia, OH 44056
o N.R. Fernandez, Product Manager, Specialty Products
Jim Walter Corporation (Celotex Corporation)
1500 N. Dale Mabry Street
Tampa, FL 33622
• Welders Supply Company, Incorporated
1 Plant Street
Billerica, MA 01821
Fiber/Product Substitutes
For this category, fiber and product substitutes are covered together
since for many of the asbestos sealant and coating products the only
substitutes available are the fiber replacement category. The consensus of
the asbestos industry is that,"for most sealant and coating products, no
viable substitutes for asbestos exist at this time. Because of this,
manufacturing plants, especially those producing roofing products, are subject
to shutdowns as a result of slowdowns or strikes at the asbestos mines.^ In
an effort to avoid this problem in the future, most major manufacturers are
actively searching for viable substitutes. An acceptable substitute must be:
• Noncombustible
• Resistant to decay, many acids, and vermin
• Durable
« Strong enough to reinforce other binders
• Unaffected by temperatures up to 500°C (930°F)
e Economic
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There are no substitutes available that possess ail of the above, but for
applications where several of the characteristics are not necessary, a
substitute may be applicable. Alternatives for each sealant category
including special qualities, product composition, uses and applications,
manufacturing and current market considerations are presented next, by
individual category.
Sealants—
Special qualities—The resistance to decay, many acids, and vermin
displayed by asbestos must also be a quality of substitute sealants, as well
as the ability to withstand temperature changes and remain durable and
effective. One alternative fiber, Pulpex, by Lextar, is currently being
evaluated for this application. It gives high viscosity, improves slump
resistance, and minimizes shrinkage. Specific Pulpex qualities include a
specific gravity of 0.90, melting point of 165°C, average fibril length of
0.8 mm-1.5 mm, fibril diameter of 20-40 y, a surface area of 5-10 m^/g, a
moisture content of less than 5% and an essentially inert chemical reactivity
state.21*
Product composition—Caulks and sealants may be defined as liquid or
semiliquid fillers used to fill gaps in building and equipment construction.
They consist of elastomers and synthetic or natural oils which are fashioned
in suitable consistency to be either pourable or of greater thickness.
Kayocel®, created by American Fillers and Abrasives, Inc., of Bangor,
Michigan, is a product that may replace asbestos in asphalt-based sealants.
Their product brochures indicate that this substance is made from volatiles
(such as cellulose, starch and wood fiber impurities) and ash. As the
components of this material are essentially natural, common, every day
products (derived, in part, from waste recycling methods of landfill
throwaways), they are not listed in the NIOSH registry of Toxic Effects of
Chemical Compounds (1977). 2 Another substitute product that is currently
being evaluated for caulk and sealant applications is Lextar's Pulpex
polyolefin pulp fibers. A suggested formulation for this particular product
is represented by Pulpex-P (polypropylene), Grade AD-H for chlorinated rubber
mastic. In percent by weight figures, this may contain the following:
19.3 chlorinated rubber
5.7 chlorinated paraffin
9.5 another chlorinated paraffin
3.2 Pulpex
4.8 Ti02
46.0 Toluene
11.5 aliphatic distillate
*Reacts with strong oxidizing agents at elevated temperatures.
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Uses and applications—Currently, only a very small amount of asbestos fiber
is thought to be used in caulks and sealants. It appears that only in some
aircraft sealants asbestos has not been replaceable to date. No regulations
exist to date banning the use of asbestos in caulks and sealants; industry has
found customer resistance in certain cases where substitute material use has
been questioned, but, in general, it is felt that this category has
alternative products available, either currently or under formulation. For
example, Pulpex grade AD-H dry fluff polypropylene pulp may replace asbestos
in trowelable mastics that are formulated with chlorinated rubber or paraffin
used for crack filling of concrete and corrosion prevention.21
Manufacturing summary—Specific details about substitute product
manufacture were not obtained for this category; however, it is assumed that
most are made by batch process as described in asbestos sealant manufacture.
It is known that Pulpex is made by adding sufficient solvent to cover the
blade of a Cowles disperser, then mixing in ingredients at 2,000 rpm until
smooth. After this, other components such as Pulpex are added and again, this
time at a slow speed, the batch is mixed until smooth.21
Roof Coatings and Cements—
Special qualities—For both roof coatings (cold applied liquids) and roof
cements (trowel applied compounds with a consistency of soft margarine), no
single raw material has been found that can either replace the functions
performed by asbestos in solvent thinned asphalt roof coatings or equal the
properties of asbestos fiber in achieving needed cement body. In the case of
cement substitution, the product must still be suitable for troweling and at
the same time must contain enough bitumen after evaporation of the solvents to
deposit a thick film on the roof surface which also resists weathering.23
Asbestos is usually used, due to the fact that:
« It enables the liquified asphalt to remain as a protective layer on
the surface in question, otherwise it would penetrate entirely into
the surface it should be rejuvenating; on surfaces where penetration
would be minimal (such as metal) or with a great slope, the asbestos
fibers stop running or sagging.
• It reinforces the asphalt; after the solvents have evaporated, the
asbestos fibers prevent the asphalt from cracking as expansion and
contraction from temperature fluxuations affect the surface.
• It retards the oxidation and deterioration of the asphalt from the
sun rays.
a It retards melting and running of the roof coating in the event of
fire.23
Any substitute product must also possess such properties. Several companies
have investigated the use of other available fibers such as fiberglass,
polyethylene, polypropylene, polyesters, acrylics, cotton, and other threads
and fibers, but none have proven to be an acceptable substitute for
asbestos. '^'2^>25 A major problem is that none of the above become wetted
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by the asphalt; they "ball-up" when applied with a trowel.^ Fiberglass
provides adequate reinforcement but does not contribute to the viscosity of
the product and lacks chemical affinity for asphalt. A number of proprietary
materials are currently being investigated but more specific information is
not available in most cases. Information on Pulpex by Lextar was available,
and will be covered here.
At low concentration and in combination with talc, Pulpex is reported to
improve product mixture uniformity with excellent wet and dry slump
resistance. It can also be airless sprayed. Specific qualities include, in
percent by weight, brookfield viscosity (cps) at 22°C (73°F) and 10 rpm of
22,000 and 270,000 cps for roof coating and roof cement respectively. Product
uniformity data includes, after 22°C (73°F)/7 days a slight bleeding and
stirring in for both products, and after 65°C (150°F)/7 days more bleeding and
stirring in. A "pass" rating was given on wet slump resistance at 38°C
(100°F), dry slump resistance at 65°C (150°F) and pliability at 0°C
(32°F).2l it should be noted that only a low concentration of Pulpex is
needed to achieve the same viscosity level as with asbestos.
Product Composition—There are a number of types of roof coatings, the
largest segment of sales being devoted to asphalt liquified with solvents and
bodied with asbestos fiber. The asphalt is liquified with solvents so that
heating is not necessary before application.
Roof cements, used in large quantities for construction and repair of all
types of roofs, commonly consist of solvent thinned asphalt or coal tar bodied
into a heavy consistency with asbestos and other mineral fillers.
Substitute products have attempted to replace the asbestos mentioned
above with replacement fibers. Tremco uses a cellulosic material costing
approximately $1.35/lb. The average fiber length in their product is greater
than the asbestos used in roofing sealants and only one-sixth as much fiber is
required in the product.^
Consolidated Protective Coatings Corporation uses a fiberglass/asbestos
mixture in its roofing sealants. The fiberglass, which has longer fiber
length, forms an interlocking "jackstraw" mesh with the shorter asbestos
fibers improving the strength of the product. However, this combination is
not actually a substitute because the quantity of asbestos is comparable to
that used in conventional sealants. 5
One Lextar Pulpex product consists of (% by weight):^1
Roof Coating Roof Cement
Ashpalt
cutback (65% solids) 87.5 70.0
Talc (5 y.average size) 5.5 13.5
Talc (16 M average size) 5.5 13.5
Pulpex P* grade AD-HR 1.5 3.0
100.0 100.0
*Pulpex "P" is the polypropylene pulp
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Others are made with aluminum paste resulting in aluminum asphalt roof
coatings.^1
Uses and applications—Roof coatings are used to rejuvenate and protect
most types of roofs, except the typical home owner's shingle roof. They are
often found on home garages, porch decks, apartment houses, sheds, farm
buildings, industrial buildings and commercial buildings of all sorts,
including stores, shopping centers and office buildings. They can also be
used as water proofing mastics on porous walls of buildings above and below
ground and on surfaces such as concrete block, poured concrete and brick.
They are applied either by brush or by spray. Roof cements are used to seal
the openings too large for liquid application. Again, they are used on almost
every type of building, no matter what type of roofing system is employed,
including, in the case of cements, the typical shingle roofed home. They are
used to seal such places as vent pipes, chimneys, roof heating and air
conditioning units, gutters, gravel stops; anywhere a vertical and horizontal
surface meet or where a projection is encountered. One Pulpex grade has been
designed specifically for use in asphalt, solvent cutback coatings, and
mastics.2
Manufacturing processes—Industry has had a strong incentive to find ways
of manufacturing roof coatings and cements without asbestos fibers. Asbestos
supply may be disrupted and cannot be assured, and other alternatives are
currently being tested. However, there are several factors in the production
of substitute coatings and cements that influence the inability, to date, to
produce equal quality alternatives to the asbestos products. As has been
previously discussed, asbestos is unique among known raw materials in that it
is a completely inert, indestructible mineral that can be processed into a
fiber. This fiber partially adsorbs the vehicle into which it is placed,
becoming an integral part of that medium without settling or floating. With
the addition of only small amounts of asbestos fiber, a large degree of body
can be added, turning a liquid into the consistency of soft butter. In
comparison, glass is unabsorptive so the coating is not homogeneous, and it
also floats in roof coating mediums. Rock wool also lacks absorption
properties. Fiberous talcs, wollastonites, ceramics, and clays are not
fibrous enough to duplicate the performance of asbestos. Most other fibers
available are organic-they melt, deteriorate on aging and also are likely to
have poor chemical resistance.22
Therefore, it seems at present that the only method of manufacturing
reasonably satisfactory asbestos-free roof coatings and cements is to combine
a substitute fiber (usually of less than satisfactory quality) with a variety
of mineral fillers, wetting agents, plasticizers and synthetic thixotropes.
With a great variety of different roof coatings, cements, and mastics, this
leads to many different new formulations needed. With present tests, the end
product has always been a medium containing less asphalt, tar, or other
water-proofing oil and much more filler material than when asbestos is used,
often leading to a lessening of waterproofing and weathering properties, and a
30 to 70 percent increase in energy requirements for manufacture.2-* in
addition, many substitute formulas do not meet present Federal Specifications
on asphalt
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roof coatings and cements, as they exceed the maximum filler content
permitted. Supply considerations must also be injected into the substitute
market picture. Some of the alternative raw materials are highly specialized
and only produced in small volumes. These types of materials would need time
to be brought up to a sufficient volume level, if increased production was
feasible at all.
General manufacturing considerations follow. Tremco, Inc. reports that
they have a proprietary substitute that has the required affinity for asphalt
to provide appropriate biological and spraying characteristics.2^ Koppers
Co. has also developed an acceptable but proprietary substitute for which no
information is currently available.2° Gibson Romans Company manufactures
some asbestos-free roof coatings and cements but, as they are about 15 percent
more expensive and also inferior to the asbestos products, they are not
marketed in the U.S.23 However, they are shipped to Sweden where asbestos
has been banned, so manufacturing performance on a large scale could be
observed if a company in the U.S. thought this to be a marketable
product.22 Some Pulpex products are manufactured in a Hobart® mixer;
others, with a Cowles disperser as well. This product notes that material
safety data sheets should be obtained prior to the use of these products.21
In summary, for this product category, asbestos-free solvent based roof
coatings and cements may be produced by complicated formulating techniques,
but they are generally more expensive and inferior in quality and some do not
meet Federal Specifications. In addition, the asbestos industry submits that
asbestos used in roof coatings and cements is completely encapsulated. "
Automobile and Truck Undercoating—
Special qualities—The properties of asbestos that are important for
automobile and truck undercoating products are: high thermal resistance,
affinity for asphalt to control viscosity, high fiber density, strength, and
durability. The affinity for asphalt is required to ensure complete
encapsulation of fibers. Small fiber dimensions result in a high density
product with soundproofing abilities. High tensile strength is needed to hold
the product together and thermal resistance is required to retain this
strength at the elevated temperatures experienced. Control of viscosity is
also required to retain tensile strength at the elevated temperatures and to
prevent unwanted flowage of the undercoating resulting in the loss of
waterproofing abilities. No suitable substitute is being manufactured. A
substitute should possess the qualities listed to be an adequate replacement
for asbestos. Substitutes such as fiberglass, fibrous alumina, and magnesium
silicate fiber do not possess the affinity for asphalt or the ability to
control viscosity which make asbestos unmatched for use in undercoating
products.^ Zinc may be used to provide resistance to rusting, but, by
itself, it is not sound deadening;^ therefore it is often used in
combination with asphalt/asbestos undercoating.
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Product composition—A representative of Chrysler Corporation suggests
that fiberglass, fibrous alumina, and magnesium silicate fiber might be used
as asbestos substitutes. Zinc has also been used in undercoating.
Uses and applications—Undercoating products are used to protect the
undersides of cars and trucks from wear due to road conditions and weathering
from the natural elements. They also help to deaden sound transferred from
the road to the driver.
Manufacturing summary—Information for substitute product manufacture was
generally not available. It is known that Pulpex may be able to serve in this
area.
21
Linings and Chemically-Resistant Coatings (Asphalt- and Nonasphalt-Based)—
Special qualities—Asbestos is used in nonasphalt-based coatings
resistant to alkali, acid, water, and weather. Table 65 lists substitutes for
these applications, their physical characteristics and special qualities.
TABLE 65. SUBSTITUTES FOR ASBESTOS IN RESISTANT LININGS AND COATINGS27
Resistant characteristics
Name
Talc
Asbestos
Barite
Diatomite
Silica
Clay
Mica
Key: P =
F =
Alkali
F
F
G
P
P
F
G
Poor
Fair
Acid
G
G
G
E
E
G
G
Water Weather
E
E
G
E
E
E
E
G
E
E
F G
G
G =
E =
G
Good
Excellent
Physical characteristics
Fibrous-plat el ike
Fibrous
Cubical, heavy
Porous
Hard, sharp crystals
Platelike
Platelike, used to reduce
moisture vapor transfer
Product composition—Substitutes include talc, barite, diatomite, silica,
clay, and mica as listed above. In addition, a representative of Dudick
Corrosion-Proof Manufacturing, Inc., states that they have a new proprietary
formula for acid and alkali resistant tank linings.2° However, at this
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time, no specific information on this product has been made available.
Electro Chemical Engineering and Manufacturing Company has tried high
tiiinperature glass as a substitute for asbestos in asphalt mastics. It did not
prove to have the necessary affinity for asphalt and therefore could not be
sprayed to produce a desirable pattern.^'
Uses and applications—Linings and coatings are used wherever there is a
need to protect a product from such conditions as saltwater, salt solutions,
organic acids, mineral acids or petroleum products.
Manufacturing summary—Manufacturing information for the Dudick and
Electro Chemical Engineering products was not available.
Spackle and Dry Wall Joint Compounds—
Special qualities—Asbestos was used to impart lubricity, workability,
water binding and pseudoplasticity to a wet mix, and, being fibrous, provided
reinforcement to the cement upon drying.29,30 However, the use of asbestos
in these products was banned in 1977. Substitute products developed, such as
attapulgite clay, exhibit good plasticity, stability, water retention,
cohesiveness, and viscosity.
Another substitute product developed by Hercules, Inc., Delaware uses
water-insoluble carboxymethylated cellulose derivatives and is said to be
substantially equivalent in performance to those products currently available
commercially. They are suitable for manual application by trowel or can be
applied mechanically with the addition of water at the job site just prior to
use.3"
Product composition—Joint cements heretofore employed with wallboard
have contained a resinous binder, limestone, clay, mica, and asbestos as the
principal dry ingredients which were mixed with water, forming a dope. The
new attapulgite product is a fibrous clay with a chain-like structure. The
cellulose derivative is made up of a resinous binder, mica, clay, and
limestone as major dry components, along with a fibrous, carboxymethylated,
substantially water-insoluble cellulose derivative selected from the class
consisting of cross-linked carboxymethyl cellulose (CMC) and other cellulose
derivatives. Typically, a dispersant, a defoamer, a preservative, and a
thickener are also added. These joint cements are marketed as fully
formulated ready-to-use cement; i.e., already containing water, as well as in
dry powder form to which water is added at time of use. ^
Uses and applications—These products are used with wallboard to form
seals in their construction. The use of attapulgite for this application is
said to increase product price by only 12 to 13 percent. The price of the
cellulose product is also competitive. This may be the best candidate for the
replacement of asbestos in these products.
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Manufacturing summary—Details on the manufacture of the attapulgite
product were not available for this report. Hercules reports that their
product is made by preparing a ready-mix formulation, to which water and
binder latex are charged in a mixing apparatus. This is mixed for a short
time before the dispersant, defoamer, and preservative are added. The dry
ingredients (limestone, mica, clay, carboxymethylated cellulose derivative,
and structure additives, if used) are dry blended and added incrementally to
the stirred liquids. After the last of the dry ingredients are added, the mix
is stirred for about another 10 minutes at low speed with occasional stopping
to scrape down the sides of the bowl.3"
Texture Paints—
Special qualities—Major texture paint manufacturers (Bondex
International and the Synkoloid Company) indicate that asbestos is no longer
used in texture paints.^>13 xhis is confirmed by several minor
manufacturers and distributors. This is probably a result of the Consumer
Product Safety Commission ban on consumer patching compounds containing
respirable asbestos because these products are manufactured by the same
companies. Properties required in a substitute are resistance to vermin,
heat, ozone, and ultraviolet and infrared radiation. ^ The substitute must
also be available in various fiber dimensions to produce differing textures.
To date, it has been found that the organic substitutes react with infrared,
ultraviolet and heat radiation and ozone; hemp is often attacked by vermin,
and the inorganics do not possess the fibrous structure necessary to bridge
cracks. Therefore, texture is now often produced by worker's tools. ^
However, some products by Lextar—several Pulpex grades—are covered here.
One is a replacement for interior textured paints, and another for ceiling
texture compounds. Also being evaluated is a product for exterior block
filler paints. Special qualities of the interior texture paint include:
specific gravity of 0.96, melting point of 132°C, moisture content of 50
percent and essentially inert chemical reactivity. The block filler is
similar; special qualities for the ceiling texture compounds include the same
specific gravity, melting point, and inert activity, but a moisture content of
less than 5 percent.21
Product composition—Possible substitutes include fiberglass, rayon,
nylon, polypropylene, polyester, and hemp fiber. Other fillers that can be
used are clays, diatomite, talc, perlite, silica, mica, barite, calcium
carbonate, bentonite and others. None possess the combination of properties
attributable to asbestos and all yield inferior products.
f
Swells in chlorinated hydrocarbons.
237
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An example of the suggested formulation of two Pulpex products is given
Interior textured paint
(in lb/100 gal)
Water 416.8
Hydroxyethyl cellulose 3.0
Dispersant 11.2
Mildewcide 3.0
Ti02 50.0
Mica, water ground 50.0
Polyvinyl acetate latex 180.0
Diatomaceous silica 100.0
Calcium carbonate 414.0
Attagel® 40 15.0
Pulpex-E,a grade D-V 14.8
aPulpex "E" is polyethylene pulp.
Ceiling texture compounds
(parts)
CaC03
Diatomaceous silica
Clay
Talc
Ground mica
Calcined aluminum
silicate
Starch
Carboxymethyl cellulose
Preservative
Polystyrene foam chips
Pulpex-E,a grade D-H
Water
592
7
13
89
89
148
36
4
2
4
4
Added to
desired
viscosity
Uses and applications—Texture paints are used to give a textured
appearance to ceilings and other substrates where this look is desired. As
mentioned, worker's tools can perform the same function. The Pulpex products
improve stipple characteristics and hiding power in interior textured paints;
provide heavy body to block filler paints, reducing mud cracking and improving
bridging of block imperfections; and in ceiling texture compounds, give bulk,
crack resistance, and improved adhesion.^
Manufacturing summary—Interior texture paint substitutes made by Lextar
are mixed, ground, and then mixed again until dispersed. Exterior block
filler paints are mixed, dispersed under high shear, then other ingredients
are added under low shear, finally mixing, until dispersed. The ceiling
texture compound ingredients are dry blended in a Hobart® mixer. Resulting
formulations can be sprayed with a texture spray gun.^l
Pipe Coatings—
Special qualities and product composition—With respect to pipe coatings,
there are a variety of asbestos-free product substitutes for asphalt mastic.
The following materials have been used as successful pipe coatings in various
applications:^
• Enamels - Enamels have been widely used as a protective coating for
65 years, combined with glass or felt to obtain mechanical strength
238
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for handling. Enamel systems may be designed for installation and
use within an operating range of 1°C to 82°C. Enamels are .effected
by ultraviolet rays and hydrocarbons.
Extruded Plastics (Polyethylene and Polypropylene - The extruded
plastic coatings have been available to the industry since 1965 and
their growth and acceptance has been remarkable during this period.
Initial problems of stress, cracking and shrinkage have been
minimized by better quality and grade of high molecular weight
polyethylene resins.
Fusion Bonded Thermosetting Powder Resins - Fusion bonded powder
coatings were first introduced in 1959 and have been commercially
available since 1961. These coatings are applied to preheated pipe
surfaces 204°C to 260°C with and without primers. This coating is
applied in a 12 to 25 ml thickness. The fusion bonded powder
coatings exhibit good mechanical and physical properties and may be
used above or below ground.
Liquid Epoxy and Phenolics - There are many different liquid systems
available today that cure by heat and/or chemical reaction. Some
are solvent types and others are 100 percent solids. Their use is
mostly on large diameter pipes where conventional systems may not be
available or where they may offer better resistance to operating
temperatures in the 93°C range.
Tapes - Polyvinyl, polyethylene and coal tar tapes are widely used
in the field for joint coating protection or for odd shapes or bends
on mill applications. The important developments in plastic tapes
have been an increase in their thickness, use of stronger resins and
improved adhesion by the use of new types of adhesives and primers.
Wax Coatings - Presently not very much is heard regarding the use of
wax coatings. However, they have been in use for 48 years and are
still utilized on a limited basis. Microcrystalline wax coatings
are usually used with a plastic overwrap for protection.
Polyurethane Foam Insulation- Efficient pipeline insulation has
grown increasingly important as a means of operating hot and cold
service pipelines. While generally used in conjunction with a
corrosive coating, if the proper moisture vapor barrier is used over
the urethane foam, effective corrosion protection is obtained.
Concrete - Mortar lined and coated pipe have the longest history of
use to protect steel or wrought iron from corrosion. However, today
concrete as a corrosion coating is mainly limited to internal
lining. The external application is applied over a corrosion
coating for armor protection and negative buoyancy in marine
environments.
239
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Uses and applications—Pipe coatings are used to protect pipes from
hostile surroundings. It is a difficult task to select a coating that will be
an effective electrical insulator and provide other desirable characteristics
which will achieve a users needs. The selection of a coating requires
knowledge of the operating and installation conditions to be able to evaluate
the properties of the pipe coatings required to fill these needs.
Manufacturing summary—Information on the manufacturing processes used to
make the alternatives listed was not available.
COST COMPARISON
Roof Coatings and Cement
Table 66 lists costs for several fibrous materials proposed as
substitutes. All of these fibers are significantly more expensive and are
thought to yield an inferior product. Other roof coating data is found in
Table 66a for Pulpex fiber. Here it may be seen that costs are equal, thus
negating cost as a factor in roofcoating choice. In some instances3 the
substitution of an alternative fiber for asbestos may require manufacturing
changes which would involve additional costs.
TABLE 66. COSTS OF FIBROUS MATERIALS FOR
ROOFING COATINGS COMPARED WITH
GRADE 7 CHRYSOTILE1
Fiber Cost in $/lb ($/kg)
Chrysotile (Grade 7) 0.06-0.12
(0.13-0.26)
Fiberglass 0.40 (0.90)
Polypropylene 0.35 (0.80)
Cellulose 0.60 (1.30)
Cotton 0.20 (0.45)
Proprietary No. la 1.35 (3.00)
aTremco, Inc.
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TABLE 66a. PULPEX VERSUS ASBESTOS PRICES,
$/lb ($/kg)
Product Pulpex Asbestos
Asphalt roof coating 0.13 (0.26) 0.12 (0.24)
Aluminum asphalt roof coating 0.45 (0.90) 0.45 (0.90)
Asphalt roof cement 0.11 (0.22) 0.11 (0.22)
Linings and Coatings
Several substitutes for asbestos in linings and chemically-resistant
coatings are currently commercially available. Depending on the particular
application, these substitutes may perform as well or better than asbestos.
Cost data is presented in Table 67. In terms of cost, the asbestos substitute
materials are comparable to asbestos.
TABLE 67. COSTS OF SUBSTITUTES IN RESISTANT
LININGS AND COATINGS32
Name Cost in fc/lb (fc/kg)
Chrysotile (Grade 7) 0.06-0.12
(0.13-0.26)
Talc 0.06 (0.13)
Barite -
Diatomite
Silica
Clay 0.04-0.08
(0.09-0.18)
Mica 0.05 (0.10)
241
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Texture Paints
There are several fiber substitutes available to replace asbestos in
texture paints. A cost comparison is given in Table 68. Even the higher
priced nonasbestos products cost no more than asbestos products because only a
small amount of fiber (approximately 1 percent) is involved. In spite of any
cost difference that might acrue, these substitutes may yield an inferior
product. Texture may also be produced by workers tools, thereby eliminating
the need for an asbestos substitute fiber for this application.
TABLE 68. COSTS OF SOME SUBSTITUTES FOR
ASBESTOS IN TEXTURE PAINTS*
Material Cost in $/lb ($/kg)
Chrysotile (Grade 7) 0.06-0.12
(0.13-0.26)
Fiberglass 0.05 (1.10)
Mica 0.05 (0.10)
Talc 0.06 (0.13)
Carbonate 0.04-0.08
(0.09-0.18)
Nylon 0.60 (1.30)
Polypropylene 0.35 (0.80)
xlnfonnation from nonpublished document
done for OSHA-"Part I: Technological Feasi-
bility Assessment and Economic Impact
Analysis" on Asbestos Dust.
Sealants, Automobile and Truck Undercoating, Spackle and
Dry Wall Joint Compounds
It has been indicated by Chrysler Corporation that potential substitutes
for undercoatings cost 4 to 30 times as much as grade 7 chrysotile asbestos.
No cost data was available for any of the other product categories. The use
of asbestos in spackle and dry wall joint compounds was banned by the Consumer
Product Safety Commission in 1977. Nonasbestos containing formulations have
since become available at competitive prices.
242
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CONCLUSION
Availability and properties of substitutes for asbestos-based sealants
have been investigated for six product types:
• Sealants
• Roofing Coatings and Cements
• Automobile and Truck Undercoatings
• Linings and Coatings
• Texture Paints
• Spackle and Dry Wall Joint Compounds
The properties required for these applications span the range of
properties required by most of the asbestos—based sealant products. To some
degree it is possible to draw conclusions for applications not specifically
discussed herein.
The first two products have generally been compounded with asphalt and
asbestos. Early attempts to find a direct replacement for asbestos fibers
failed because most fibrous materials are not readily wetted by asphalt as is
asbestos. For sealants, it is generally felt that alternative products are
available, even if their properties are not quite equal to those of asbestos.
Kayocel is such a product, produced by Fillers and Abrasives, Inc. of
Michigan. Asbestos-free solvent based roof coatings and cements may be
produced by complicated formulating techniques, but they are generally more
expensive and inferior in quality to asbestos and may not meet Federal
specifications.
Commercially available asbestos-free, asphalt-based roofing products that
provide the properties of asphalt-asbestos-based products are gaining market
acceptance. Lextar, Tremco, Inc., Koppers Co., and Gibson Romans Co. all
report the availability of products in the premarket or early commercial
stages that can be used as direct replacements for asbestos in asphalt-based
roofing products. Apparently these fiber substitute products are readily
wetted by asphalt. In some respects, their quality is not yet known although
Lextar has provided information on the special qualities of their product. It
is not known whether these same products would be suitable for use in
undercoatings. Chrysler Corporation has indicated that fiberglass, fibrous
alumina, and magnesium silicate fiber may be used in this area, although they
are much more expensive and lack special qualities."
Asbestos-based linings and chemically resistant coatings are formulated
both with and without asphalt. For asphalt formulations, several mineral
reinforcing materials (e.g., talc, barite, diatomite, perlite, silica, clay,
and mica) are available as substitutes for asbestos. Performance details are
not available.
243
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Use of asbestos in texture paints, spackle, and dry wall joint compounds
has been banned since 1977. Some substitutes are listed that may provide a
product of the quality of asbestos-based texture paint, although test
comparisons with asbestos were not available. Attapulgite is a suitable
substitute for asbestos in spackle and dry wall joint compounds. Pulpex is
available for texture paints and block fillers. In addition texture may now
be added by worker's tools.
With respect to pipe coatings—enamels, extruded plastics, fusion bonded
thermosetting powder resins, liquid epoxy, tapes, wax coatings, polyurethane
foam insulation, and concrete are all possibilities for substitution.
Overall, this category appears to have some feasible substitutes, but a
quality replacement for asbestos across the board for the many applications
mentioned is lacking. However, new data in this area has provided additional
products in many areas which may prove capable of replacing asbestos in all
areas and have already proved acceptable in some.
244
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REFERENCES
1. Clifton, R. U.S. Department of the Interior. Bureau of Mines. Mineral
Industry Surveys - Asbestos in 1978. Washington, D.C. August 22, 1979.
p. 3.
2. Clifton, R. Preprint from the 1980 Bureau of Mines Minerals Yearbook.
Asbestos, p. 4.
3. Fagan, Doris M. (editor). International Industry Review - 1979,
Part II: The Asbestos Mining Industry - United States. Asbestos.
6K6): 16. December 1979.
4. Telecon. N. R. Fernandez, Celotex Corp., with David Cook, GCA. January
29, 1980. Asbestos in roofing materials.
5. Telecon. Edmund Fenner, Johns-Mansville, with David Cook, GCA. January
15, 1980. Asbestos in various sealant products.
6. Telecon. Jack H. Engel, Chrysler Corp., with David Cook, GCA. January
17, 1980. Asbestos in automobile undercoatings.
7. Consumer Product Safety Commission. Title 16, Chapter IV, Part 1304.
Ban of Consumer Patching Compounds Containing Respirable Freeform
Asbestos.
8. Telecon. Sika Chemical Corp. with David Cook, GCA. January 18, 1980.
Asphalt mastics.
9. Telecon. Spender Kellogg Division of Textron with David Cook, GCA.
January 18, 1980. Concrete protective coatings.
10. Telecon. Welders Supply Co., Inc. with David Cook, GCA. February 5,
1980. Welding rod coatings.
11. Telecon. Igo's Welding Supply Co. with David Cook, GCA. February 5,
1980. Welding rod coatings.
12. Telecon. Jack Fleming, Bondex International, with David Cook, GCA.
January 16, 1980. Texture paints.
245
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13. Telecon. William Pass, Synkoloid Co. with David Cook, GCA. January 16,
1980. Texture paints.
14. Telecon. Charles Spector, Everseal Manufacturing Co., Inc., with David
Cook, GCA. January 17, 1980. Texture paints.
15. Telecon. Harry Schwartz, Baltimore Paint and Coatings Group of Dutch Boy
Paints with David Cook, GCA. January 22, 1980. Texture paints.
16. LaShoto, P. Final Trip Report - Armstrong Cork, Fulton, N.Y. GCA
Corporation/Technology Division, Bedford, Mass. July 1979. 6 p.
17. Roy F. Weston Environmental Consultants. Technology, Feasibility and
Economic Impact of OSHA Proposed Revision to the Asbestos Standard
(Construction excluded). Asbestos Information Association/North
America. March 26, 1976.
18. Meylan, W. M., et al. Chemical Market Input/Output Analysis of Selected
Chemical Substances to Assess Sources of Environmental Contamination:
Task III - Asbestos. EPA-560/6-78-005. August 1978. p. 61.
19. W. E. Davis and Assoc. (Leawood, KS). National Inventory of Sources and
Emissions: Asbestos - 1968. U.S. Environmental Protection Agency Office
of Air and Water Programs OAQPS, Research Triangle Park, NC. APTD-70,
February 1980.
20. Telecon. Jerry Stanley, Celotex, Tampa, FL, with Anne Duffy, GCA
Corporation, GCA/Technology Division, May 4, 1981, Call No. 35.
21. Lextar - A Hercules/Solvay Company, Wilmington, Delaware. Product
literature - Table 1, 2, 3, cost comparison, etc. Pulpex polyolefin
pulps and information. Also, Bulletin Nos. P-9 and P-10 and letter to
Mr. Richard Guimond, EPA from Edward Engle, Pulpex, August 25, 1981.
22. Putting the Useless to Use. American Fillers and Abrasives, Inc.,
Bangor, Michigan.
23. Wormser, E. S. Speech at Substitutes to Asbestos Conference, EPA,
Arlington, VA. July 14-16, 1980.
24. Telecon. Ken Brzozowski, TREMCO, Inc., with David Cook, GCA. January
18, 1980. Substitute fibers for roofing products.
25. Telecon. Fred Mallay, Consolidated Protective Coatings Corp., with David
Cook, GCA. January 18, 1980. Substitutes for roofing products.
26. Telecon. Colin Hermus, Koppers Co., with David Cook, GCA. February 6,
1980. Roofing materials.
246
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27. M. Grayson, and D. Eckroth. Encyclopedia of Chemical Technology, Third
Edition, Volume 6. Wiley-Interscience. New York, N.Y. 1978. p. 461.
28. Telecon. T. Dudick, Dudick Corrosion-Proof Manufacturing, Inc., with
David Cook, GCA. January 18, 1980. Acid and alkali resistant coatings.
29. Telecon. Ken Heffner, Electro Chemical Engineering and Manufacturing
Co., with David Cook, GCA. January 18, 1980. Asbestos-containing
mastics.
30. U.S. Patent No. 3,891,528, June 24, 1975. Joint Cement Compositions
Utilizing Water Insoluble Carboxymethylated Cellulose Derivatives as
Asbestos Substitutes Inventory, Armand J. Desmarais, New Castle, Delaware.
31. EPA Substitutes to Asbestos Conference. Arlington, VA. July 14-16, 1980,
32. Pigg, B. J., A.I.A. letter to Rich Guimond, EPA, 12 August 1980.
247
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SECTION 9
REINFORCED PLASTICS
ASBESTOS PRODUCT
Special Qualities
Asbestos fibers have been used in combination with plastics since the
1920's when asphalt floor tiles were first introduced.1 Asbestos fibers, when
added to polymeric materials, modify the physical and chemical characteristics
of the composite. Fibers, in general, function as both fillers and reinforcing
agents. The benefits of using asbestos derive from the fact that asbestos has
the advantages of both a mineral and a fibrous binder carrier with reinforcing
action.2
Asbestos is particularly useful in molding compounds because it will
impart very good surface finish, toughness,* resistance to heat and fire,
and less shrinkage and warpage than other fibers. Also, the addition of
asbestos improves the handleability of the product during processing. For
example, putty-like compounds become much less sticky.
Product Composition
Asbestos fibers are used to reinforce many plastics including phenolic,
urea, melamine, unsaturated polyesters, diallyl phthalate prepolymers, epoxies,
silicones, polypropylene and nylon. Phenolic molding compounds (thermosetting
polymers) are the major users of asbestos in reinforced plastic applications
outside of floor coverings, friction materials and gasketing, which are dis-
cussed in other sections of this report. Consequently, the following discus-
sion focuses primarily on phenolic molding compounds.
Bulk fiber is the most widely used form of asbestos in combination with
plastics. Chrysotile is used in the largest quantities in plastics for molding
compounds, with crocidolite, anthophyllite, tremolite, and amosite used in
lesser amounts. Chrysotile classified according to the test used by the Quebec
Asbestos Mining Association (QAMA) in grades 1 through 5 is normally used for
its reinforcing properties. Grades 6 and 7 fibers are used for their thix-
otropic characteristics (to control flow), heat resistance, dimensional sta-
bility, and low cost. The crocidolite and anthophyllite varieties of asbestos
are used for specialty purposes where corrosion resistance is important.5
^Toughness refers to the ability of the molded material to resist impact
(high strain rate) mechanical loading. The Izod test is an impact strength
test which is one of several methods of characterizing toughness.
248
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A breakdown of the various chrysotile grades and crocidolite and antho-
phyllite asbestos used in bulk by primary plastics manufacturers in 1980 is
as follows: chrysotile grades 1, 2, 5, and 7, 1400 metric tons, and croci-
dolite, 100 metric tons. Thus, total consumption of asbestos for plastic
products was 1500 metric tons, down more than 3400 tons from 1978 figures.6
Today, as in the past, most of the asbestos used in plastic molding com-
pound manufacture is chrysotile Grade 7, a short fiber that functions more as
a filler than as a reinforcing agent.2
Rogers Corporation, one of the primary manufacturers of asbestos-reinforced
phenolic molding compounds, reports that their asbestos products contain from
10 to 55 percent asbestos depending on product application.5'*
Uses and Applications
Asbestos-reinforced plastic molding compounds are used in a variety of
applications including the electrical, electronic, automotive, and printing
industries. In particular, the Rogers Corporation uses asbestos in the fol-
lowing products: asbestos-reinforced board material used in the printing
industry as a matrix from which multiple rubber or plastic printing plates
can be molded; automobile transmission reactors which are employed to direct
the flow of transmission fluid; commutators for electrical motors, switches,
and circuit breakers.1* Rogers Corporation's RX 468 DN (asbestos-reinforced
plastic) is General Motors' choice for molded commutators used in fan drive
motors installed in its new 1980 front wheel drive (X-Model) compacts.7 GM
says the asbestos material retains its strength at temperatures over 500°F,
has high impact strength and dimensional stability, and is more economical
than equivalent glass-and-mineral filled materials. Asbestos-filled phenolics
may also be used to make pot handles and various knobs and other components of
large and small appliances, such as clothes washers and dryers, dishwashers,
refrigerators, portable heaters, popcorn poppers and broilers.8
Product Manufacturing Summary
Manufacturing Process—
The manufacturers of asbestos-reinforced plastic products can be divided
into two segments. A small number of primary manufacturers produce molding
compounds in pellet or flake form, package it, and sell this granulated mate-
rial to a myriad of secondary manufacturers where the final product is shaped
and finished. The primary manufacturing steps consist typically of: (1)
fiber receiving and storage; (2) fiber introduction; (3) dry blending; (4)
resin formation; and (5) packaging and shipping. The secondary manufacturing
steps usually are at a facility remote from the primary processing and consist
of: (1) resin receiving and storage; (2) resin introduction; (3) forming;
(4) curing; (5) finishing; and (6) product packaging and shipping to consumers.
*In addition, Rogers offers a complete line of nonasbestos reinforced molding
material.
249
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Name and Location of Manufacturers—
The most important primary manufacturers of phenolic molding compounds
which currently produce asbestos-filled compounds are listed in Table 69.
TABLE 69. .PRIMARY MANUFACTURERS OF PHENOLIC
MOLDING COMPOUNDS1'9'3
Plant name Location
Plaslok Corporation Buffalo, NY
Plastics Engineering Sheboygan, WI
Reichhold Chemicals Elizabeth, NJ
Resinoid Engineering Skokie, IL
LaPorte, IN
Newark, OH
Rogers Corporation Manchester, CT
•a
Augmented by GCA telephone contact.
Production Volumes—
In 1976, 19,500 metric tons of asbestos fibers were consumed in the pro-
duction of asbestos plastic molding compounds as classified by the Bureau of
Mines.10 In 1978, however, the Bureau of Mines reported that only 4,900 metric
tons of asbestos were used in the production of plastics in the United States,1
and in 1980 the figure had decreased to 1500 metric tons.6
SUBSTITUTE PRODUCT
Methodology
Search Strategy—
An extensive literature search was conducted to obtain information on the
use of asbestos in reinforced plastics and to identify substitute products.
This literature search concentrated on the use of journals to obtain the
latest developments in the quickly changing reinforced-plastics industry.
Upon completion of the literature study an extensive telephone survey was con-
ducted to confirm information obtained in the literature survey and to acquire
new information.
Summary of Contacts—
The following people were contacted in investigating reinforced plastics.
• Leon Meyer, Hooker Chemicals & Plastics Corporation
Durex Division, N. Tonawanda, NY
February 1980
• Roger Porter
University of Massachusetts
Amherst, MA
February 1980
250
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Ronald Mount, Fiberfill
Evansville, IN
February 1980
Robert Squire, NYCO
Division of Processed Mineral Corporation
Willsboro, NY
February 1980
Vincent R. Landi
Rogers Corporation
Rogers, CT
February 1980
David Shenefield
Washington Penn Plastic Company
Washington, PA
February 1980
Bill Colclough
Fiberite Corporation
Winona, MN
February 1980
Joseph Harris
Union Carbide
Chicago, IL
February 1980
Joseph Pesce
NVF Company
Kennet Square, PA
February 1980
John Ellis
Plastics Engineering
Sheboygan, WI
February 1980
Mary Ann Atchley
DuPont
Wilmington, DE
February 1980
Mr. Groane
General Motors
Detroit, MI
February 1980
. 251
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• Sales Manager
General Electric
Pittsfield, MA
February 1980
• Donald Randolph
U.S. Gypsum
Chicago, IL
February 1980
• Society of Plastic Engineers
Greenwich, CT
February 1980
• Society of the Plastics Industry
February 1980
In researching this section, it was found that there are many fillers and
reinforcements available to replace asbestos in phenolic molding compounds. As-
bestos is not usually used unless special properties of this material are re-
quired. In order to substitute for asbestos, often two or three ingredients
must be combined to achieve the same qualities. Whether the substitutes provide
the required properties available in asbestos-reinforced molding compounds at a
reasonable cost is debatable in some instances. However, manufacturers are
finding alternatives for a majority of products previously reinforced with the
shorter-fibers of asbestos in which the physical properties of the substitute
product are equal to or exceed the asbestos product they replace.* All manufac-
turers of phenolic molding compounds have found suitable substitutes for certain
products and many manufacturers have been able to completely eliminate the use
of asbestos. Research and development in reinforcement technology has produced
several new materials which are potential substitutes and has also improved
existing substitutes. A description of materials that are currently substituted
for asbestos (mostly short fiber) and those which may be viable substitutes in
the near future follows.
Fiber Substitutes
Fibrous Glass—
Special qualities—Fibrous glass is the principal reinforcing material in
plastics and is an integral part of most new engineering plastics. Manufacturers
have chosen glass as a suitable substitute for asbestos in many applications
for many years. Manufacturers are continually improving on the properties of
glass reinforcements.
Fiberite has recently introduced upgraded versions of its 4000 series
of glass-loaded (10 to 40 percent) compounds with heat resistance in the
260° to 316°C range. Designated the 4000F series, the improved materials
are said to be based on new fiber technology that boosts physical properties
in molded parts as much as 20 percent. The new glass-reinforced compounds
are said to be particularly suitable for applications involving lightweight,
thin-wall parts.12
*For the long fiber-reinforced compounds, substitution is a more difficult
252
technical problem.3
-------
Early in 1979, General Electric introduced its Genal GF-7000 series - a
line of glass-reinforced, asbestos-free phenolic molding compounds formulated
to meet more demanding structural and dimensional stability requirements, and
to provide long-term heat resistance at temperatures up to 260°C,13 which is
comparable to heat resistance properties of asbestos-reinforced materials.
Glass content ranges from 20 to 40 percent of total filler; the balance is
mineral. According to General Electric, parts molded of the GF-7000 retain
80 percent of their physical properties after 20 hours of continuous exposure
to 204°C.1"
Genal GF-7021 and 7021P are medium glass-content materials that are
designed to replace die-cast metals and long-fiber asbestos compounds.1"1
They are especially well-suited for use in commutators, flat-iron skirts,
motor housings and transmission components. Glass-reinforced phenolic such
as GF-7000 series materials, significantly reduces current leakage in commu-
tators as compared with commutators molded in asbestos-filled phenolic.
Several drawbacks in replacing asbestos fibers with glass fibers have
been reported in the past, but have since been overcome with new product de-
velopment. The Rogers Corporation once reported that glass fibers provided
the bulk and strength needed for many applications, but, because of their
brittleness, they were unsuitable for many molding applications their customers
used.1* Now, however, Rogers has developed the RX600 and 800 series of glass-
reinforced products which are suitable in these applications.3 Another prime
consideration in molding a product was the resin's ability to flow. Glass
fibers were at first acceptable only in very simple molds; however, they have
now been adapted for use in complex molds and for fine detail requirements.
In addition, the abrasiveness of glass which was thought to affect the "tool
wear," or durability of processing equipment, has now been overcome.3
Product composition—Fibrous glass substitutes are simply made by the
addition of glass fibers to products as opposed to asbestos fibers.
Uses and applications—Fibrous glass may be used in many of the phenolic
molding compound applications that asbestos is used in.
Manufacturing summary—The manufacturing process used for glass phenolics
is similar to asbestos; however, glass fibers are only acceptable in very simple
molds (as they tend to segregate from the resin binder and fracture in complex
molds) or for fine detail requirements (see Special Qualities). Glass is also
abrasive, affecting the durability of the processing equipment. For certain
reinforced phenolics, the use of glass may necessitate a change in processing
equipment.
Carbon Fiber—
Special qualities—Carbon fibers are characterized by a combination of
lightweight, high strength, and high stiffness.15 Typical carbon composites
have a Young's modulus which is one order of magnitude greater than asbestos-
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reinforced materials.* Carbon fibers are very fragile in comparison to as-
bestos and glass.3
Product composition— Specific ingredients used in carbon reinforced
phenolics were not available.
Uses and applications—Carbon fiber composites were originally developed
to provide the aerospace industry with a strong, stiff, lightweight construc-
tion material. The composites then found their way into such sports equipment
as golf clubs, fishing rods, and tennis rackets. Detroit's search for light-
weight automotive components led to the use of carbon fiber composites for
such parts as leaf springs, drive shafts, push rods, and side door instrusion
beams. Other industrial applications include high-speed, low-inertia textile
machine parts and various components of the equipment in which alignment,
mechanical vibration, and fatigue are of principal concern.t Carbon fiber
cannot be used as an asbestos substitute in applications requiring electrical
insulation.3
Manufacturing summary—Manufacture of carbon-reinforced phenolics is pre-
sumed to be similar to that of asbestos phenolics. Detailed processes were
not available. It is known, however, that carbon fibers require compounding
with low shear mixing equipment.3
Aramid Fiber—
Special qualities—Aramid fiber is characterized by low density and high
tensile strength and flexural modulus. It has a useful temperature range
to 204°C.
Product composition—Exact specifications for this product were unknown.
Uses and applications—Introduced commercially in 1972, aramid fiber is
finding broad application where lightweight, high strength and stiffness,
resistance to stretch, and resistance to damage are important.16 The fiber
originally was developed to replace steel in radial tires. These properties
are key to its successful use as reinforcement for plastic composites in air-
craft, aerospace, marine, automotive and other industrial applications, and
in sports equipment. As with carbon fiber, aramid fibers are not likely to
be utilized as an asbestos substitute in molding compounds.3
Manufacturing summary—Details on manufacture are not available. It is
known that aramid fibers are difficult to handle in conventional compounding
equipment.3
*A high elastic modulus implies a large resistance to deformation or a stiff
material. However, high modulus is not always desirable. This is especially
true in the case of molded commutators. Toughness is sacrificed.3
However, it should be noted that carbon and aramid fiber costs are prohibitive
as compared to asbestos and glass.
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Wollastonite—
Special qualities—Special qualities of wollastonite were not available.
It is known that the hardness of wollastonite causes tool wear and harms
machinability.3
Product composition—Wollastonite is a naturally occurring calcium sili-
cate which is a mined, fibrous or needle-like shape material that is being
used as an asbestos substitute.8
Uses and applications—Wollastonite is being used in combination with
other additives in substitute compounds for short-fiber-filled asbestos ma-
terials. It does not provide the required mechanical reinforcement for high
strength compounds.3 The U.S. Mining Enforcement Safety Administration (MESA)
has classified wollastonite as a "nuisance dust" and the National Institute
for Occupational Safety and Health (NIOSH) has determined that the mineral
is neither a fibrogenic nor carcinogenic substance.8
Manufacturing summary—The primary supplier of wollastonite is NYCO, a
Division of Processed Minerals Corporation, Willsboro, NY. The other supplier
is R. T. Vanderbilt Company, Incorporated, Norwalk, CT. Specific manufacturing
processes are unknown.
Processed Mineral Fiber—
Special qualities—Special qualities of processed mineral fiber are
unknown. However, its safety category, as covered by pertinent OSHA regula-
tions, is that of an inert mineral dust.
Product composition—Processed mineral fiber is made from blast furnace
slag and silicates.
Uses and applications—This fiber is reported to be able to reinforce a
variety of plastic materials, including phenolics, nylons, polybutylene,
epoxies, and polyolefins.
Manufacturing summary—This product was recently developed by Jim Walter
Resources, Inc., specific manufacturing information was unavailable.
Polyethylene Fiber—
Special qualities—Polyethylene fibers are not yet currently available
although they may be a viable alternative in special applications in the near
future. Polyethylene fibers are high-modulus reinforcing fibers priced low
enough to fill the gap between carbon and glass.17 However, according to
researchers at the University of Massachusetts, lightweight high-modulus
(10 million psi) polyethylene fibers have relatively poor thermal resistance
properties when compared to asbestos.18
Product composition—High modulus reinforcing polyethylene fibers make
up this substitute.
255
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Uses and applications—Potential use in ranges between carbon and glass.
Manufacturing summary—Not yet available.
Product Substitutes
Clay—
Special qualities—Hooker Chemical-Durez Division has produced a full line
of granular and modular glass-filled, asbestos-free phenolics for many years,
but the supplier has come up with a new variation - a highly heat-resistant,
all-mineral-filled compound that is very competitive with glass/mineral
materials.8 Labeled Molding Grade 156, it is said to provide moldability
superior to the asbestos-containing products it replaces. According to the
supplier, parts molded from this product retain 50 percent of their properties
after 24 hour exposure to 232°C, and 50 percent after 1,000 hours at 191°C.
Product composition—The composition of this compound is proprietary;
however, it is believed to be a clay base. The properties of clay reinforce-
ments are enhanced by adding silane coupling agents to improve flexural
modulus.x 9
Uses and applications—Among the intended applications of this compound
are appliance appearance components, where it provides heat resistance and
dimensional stability. It is also aimed at such uses as auto carburetor spacers,
sealing rings, thrust washers, speedometer sleeves, appliance terminals, probe
controls, insulators, and light baffles.
Manufacturing summary—Manufacturing information was not known. The manu-
facturer of the product is Hooker Chemical-Durez Division.
Talc—
Special qualities—General Electric, the product manufacturer, claims that
this material has the same basic properties - including impact strength, dimen-
sional stability, and heat resistance - as their previous asbestos-filled prod-
ucts. GE admits that some minor product strength is sacrificed by using this
new material, and that more breakage can be anticipated as compared to asbestos-
filled phenolics; however, they suggest that manufacturers can compensate by
building thicker walled products. Talc is good to 232°C.
Product composition—General Electric's asbestos-free Genal phenolics
(apart from their new glass-filled GF-7000 series) utilize talc, in conjunction
with aluminum silicates and cellulose fibers as the major reinforcement
material. Like clay, the flexural modulus is improved by adding silane coup-
ling agents.19
Uses and applications—The predominant use for talc is for heat resistant
phenolic molding compounds in the medium temperature applications (its limit
is 232°C).
256
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Manufacturing summary—Allegedly, there is no significant difference in
the price between the asbestos-filled and the Genal product, and the same pro-
cessing equipment can accommodate the new material. Montana Talc Company
produces a silane-treated ultra-fine particle talc for nylon and ABS plastics.
Mica—
Special qualities—Mica has proven to be a suitable substitute for asbestos
in a variety of resins, however, it has had limited success when used in phenolic
molding compounds. Although mica reportedly builds stiffness much more than
equivalent loadings of asbestos, experiments performed by a mica producer,
Marietta Resources International, reportedly showed that mica-filled phenolics
cannot be exposed to elevated temperatures for long periods without blister
formation. However, this company also reports that better property retention
is exhibited for phenolic samples containing finer grades of mica.
Product composition—Mica-based materials are expected to help solve the
asbestos replacement problems in several plastic resins.19 In the forefront
is mica-filled polypropylene. Washington Penn Plastic Company recently intro-
duced two of these compounds under its Micalite tradename. One is mica-filled
polypropylene to which a small amount of chlorinated paraffin has been added;
the other uses a silane coupling agent. Research work by Ford Motor Company
resulted in the development of chlorinated-wax-mica-polypropylene. Addition
of a small amount of powdered chlorinated paraffin increases tensile and
flexural strengths, flexural modulus, and heat distortion temperature.19
Uses and applications—Ecoplastics, Ltd., states that mica-reinforced
thermoplastics are useful in applications that require low permeability, high
modulus of rigidity, high heat distortion temperature, dimensional stability
and low warpage.20 This includes use in many new industrial and automotive
products.
Manufacturing summary—Detailed manufacturing processes were not available.
Calcium Sulfate—
Special qualities—United States Gypsum reports that calcium sulfate pro-
vides improved production rates, allows high loadings, and results in low
densities in the finished product. However, calcium sulfate does not add rein-
forcing properties to molding compounds.21 In addition, its solubility in
water impairs wet electrical properties when used as an asbestos substitute. 3
Consequently, calcium sulfate is not a viable substitute in all applications.
It is believed that the material could be blended with reinforcing fibers to
broaden its application.
Product composition—This new material, recently put on the market, is a
fine calcium sulfate that United States Gypsum's Chemical Division has intro-
duced under their Terra Alba, Snow White, and CA-5 trade names. More specific
product ingredients were not known.
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Uses and applications—As this product cannot add reinforcing properties
to molding compounds, it can only be used in certain applications to date,
where this property is not necessary. Use could broaden if reinforcing fibers
could also be added to aid in strengthening the resultant products.
Manufacturing summary—As in the products mentioned previously, specific
product manufacturing processes are unknown. As for product manufacturers, in
general, the manufacturers which are producing asbestos substitute molding com-
pounds are those manufacturers which previously produced asbestos molding com-
pounds (see Asbestos Product Manufacturing Summary). In addition, there are
a variety of manufacturers that produce substitute molding compounds that,
although not intended to replace asbestos, are viable alternatives. Such com-
panies as Union Carbide, DuPont, and U.S. Gypsum produce innovative products which
are potential substitutes. The exact number of manufacturers which may have a
product capable of being an asbestos substitute cannot be determined under the
scope of this project. However, in the description of substitute materials de-
tailed in this report, an attempt was made to identify manufacturers of each sub-
stitute material.
The production volumes for manufacturers of asbestos substitute materials
were considered proprietary information in most instances and were not provided.
Consequently, production volumes of substitute materials were not available.
COST COMPARISON
There are several potential substitute fillers and/or reinforcing mate-
rials for replacing asbestos in certain reinforced-plastics applications.
Several substitute materials are economically competitive with asbestos while
others are not. The use of the more expensive substitute materials may be
offset by the associated costs of using asbestos. However, man-made substitute
materials may require more expensive manufacturing techniques to overcome
problemsgassociated with poor wettability of these fibers relative to asbestos
fibers. In addition, there may be a higher cost entailed in procuring man-
made materials as opposed to refining asbestos.22 A cost comparison of sub-
stitute materials with asbestos is shown in Table 70.
CURRENT TRENDS
There is a well-defined trend to replace asbestos in phenolic molding
compounds, documented by both the literature and by numerous conversations
with manufacturers of reinforced phenolics.23 This movement was initiated
in 1972 when General Electric Company's Plastic Division started replacing
asbestos in their phenolic products with a new talc-based filler. Since this
time, they have not used asbestos in their reinforced plastics and have
reported that they have consistently proven asbestos-free materials meet any
design criteria called for in phenolics. Through their proprietary technology,
they feel that they have developed a line of asbestos-free products equal to
or better than the discontinued asbestos-filled grades. The Durez Plastics
Division of Hooker Chemical (who reportedly have 40 percent of the total rein-
forced phenolic market) has developed a nonasbestos reinforced product. By
February 1979, their entire line of phenolic molding products (e.g., automotive,
258
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TABLE 70. COST COMPARISON'
Substitute material
(manufacturer)
Price compared to asbestos
Performance and comments
KihrouH
Genal CF-7000
glass-reinforced
compounds
(General Electric)
75c/lb (51.65/kg) vs 55c/lb ($1.20/ May be used Łor higher temperature applications; new glass
kg) long fiber asbpstos; 50c/lb
($I.IO/kB) vs lOc/lb ($0.22/kg)
short fiber asbestos*
$1.25/lb ($2.75/kg)t vs $l/lb
($2.20/kg) asbestos-reinforced
compounds
Molding Grade 156 51c/lb ($1.10/kg) vs $l/lb ($2.20/
all-mineral-filled kg) asbestos-reinforced compounds
compounds
(Hooker-Durez)
Talc
Mica
Micalite
chlorinated wax-
mica-polypropylene
(Washington Penn
Plastic Co.)
Carbon fibers
Clay
Aramid fibers
Calcium sulfate
Wollastonite
Processed mineral
fiber
6c/lb (13c/kg) vs 5-10c/lb
(ll-22c/kg) asbestos
5c/lb (UC/kg) vs l2-25c/lb
(25-55c/kg) for asbestos^
4U/lb (90c/kg) vs $l/lb ($2.20/kg)
asbestos-reinforced compounds
S10-12/lb ($22-26.50/kg) vs 13-25C/
Ib (30-55c/kg) asbestos
fiber technology enhances the physical properties of the
material; problems with abrasiveness of glass wearing out
processing equipment; process change probable.
Same as above.
Moldability superior to asbestos; good heat resistance
and dimenstional stability.
Loss of strength but can compensate by making thicker
walled product; currently used as an asbestos substitute;
limited to 232°C applications.
Adds dimensional stability and increases strength of plas-
tics; high aspect-ratio mica purported to provide middle
ground in cost performance between inorganic particulate
fillers and fiber reinforcement; blended with higher priced
substitute materials.
Same as above.
For high strength applications; increases acid resistance
in phenolics; also used as filler for thermoset plastics;
high heat resistance; specialty applications only.
75c/lb (51.65/kg) vs 55c/lb ($1.20/ Used as filler, no reinforcement; new clay base composi-
kg) long fiber asbestos; 50c/lb
($l.lO/ks) vs lOc/lb (22c/kg) short
fiber
tions are reported to maintain the acceptable balance
between heat resistance and impact strength.
$6-8/lb ($13. 20-17. 60/kg) vs 13-25C/ Used in specialty plastic reinforcements; too expensive for
Ib (?9-55c/kg) for asbestos
2-3c/lb (4-7c/kg) vs 13-25c/lb
(29-55c,'kg) for asbestos
3-13c/lb (7-29c/kg) vs 13-25c/.lb
(29-55c/kg) for asbestos
Approximately twice as expensive
as asbestos
Polyethylene fibers No data
asbestos replacement in phenolic molding compounds; can be
blended with less expensive materials.
Provides improved output rates, allows high loadings, and
results in low densities; high heat resistance; does not
add reinforcing properties to molding compounds - limited
application.
Reported to be an asbestos replacement in phenolics. The
material is cost competitive with asbestos. Has been
classified as merely a "nuisance dust."
Has been accepted as an asbestos replacement in phenolics
and epoxy gel coats.
Still in development stage; high modulus but poor heat
resistance properties.
*Glass- ar.'l asbestos-reinforced phenolic molding materials themselves are in the same approximate price range of
$l/lb ($2.20/kg).
'*"Price varies fur different grades and depends on quantity ordered.
AGeneral KlecLric incorporates mica reinforcement into Valox 752 polybutylene terephthalate (PBT) thermoplastic
polyester, in a material introduced for electrical and electronic applications. This material sells for about
90c/lb ($2/kg).20
259
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appliances, wiring, communications, electronics, and electrical switch gear)
was reinforced with this new, nonasbestos material. 2I* Fiberite Corporation,
which was at one time a small factor in asbestos-filled phenolics, also elim-
inated asbestos use several years ago. Only recently has it become apparent
that all remaining producers of phenolic molding compounds intend to pursue a
thorough phase out of asbestos, which they hoped to accomplish by the end of
1980.8 Rogers Corporation, Reichhold Chemicals, Plastics Engineering Company
and Valite Division of Valentine Sugars, Incorporated, all now intend to dis-
continue using asbestos as fast as they can develop suitable substitutes for
their remaining asbestos-filled grades. Only one small producer, Resinoid
Engineering Corporation has said that it has no plans at the moment to drop
asbestos; rather, the company appears to be taking a "wait-and-see" attitude
regarding new proposed government regulations. In addition, a very minor
amount of asbestos-filled phenolic is being imported from Canada.8
This decline in overall asbestos use reflects a dramatic trend toward
the use of substitute fibers. Manufacturers have reported that customers
have demanded asbestos-free compounds.13
Plastics Engineering (reported to be the second largest producer of
phenolic molding compounds) currently uses asbestos in some of their products,
but they have a program to replace asbestos in all their phenolic molding com-
pound products. This program began in 1977 and should be completed in 1 or 2
years. 5 Currently, every asbestos-reinforced product is available in asbestos-
free versions which are reinforced with glass fibers, clay and talc. The
asbestos-free versions are reported to have the same physical properties as
the asbestos products they replace. The time required to completely discon-
tinue the production of asbestos-reinforced materials is due to the fact that
not all of Plastic Engineering's customers have made the switch to the
asbestos-free versions. Customers find that they must modify their molding
processes to handle the asbestos-free molding material. Nevertheless,
Plastics Engineering made the decision to replace asbestos in their product
because many of their customers preferred not to process compounds containing
asbestos fiber in their operations.9 After many customers converted to
asbestos-free compounds, the demand for asbestos-filled compounds diminished
substantially. The shrinking demand caused the need for a reevaluation and
more realistic apportionment of manufacturing costs to the reduced production
volume of compounds that contain asbestos. In addition, Plastics Engineering
reports difficulty in obtaining an adequate and dependable supply of the type
and grade of asbestos suitable for molding compounds. Plastic Engineering has
urged all customers to adapt to asbestos-free compounds as soon as possible.
Reinforcement suppliers are increasing the size of their facilities to
keep pace with anticipated sales growth. For example, Micro Materials has
built three plants in the last few years for production of its Micro-Mix (a
combination of mica flakes, glass flakes, spheres, granules, and additives),
and continues to increase production by 10 to 20 percent every 4 months.
Owens Corning Fiberglass recently started up a new reinforcement plant
at Amarillo, Texas, with a nominal capacity of about 90,000 metric tons.
Certain-Teed Products has upgraded its facility at Wichita Falls, Texas, to
50,000 metric tons, and'PPG Industries Glass Fiber Division is devoting more
of its annual 118,000 metric tons output to reinforcements. Expansion is also
expected from Reichold Chemicals, which took over Ferrios glass fiber operations.
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Dupont recently announced a major expansion in aramid. Involved is a
$200 million investment that will triple capacity (to 18,000 metric tons) at
Richmond, Virginia, by 1982, and expand capacity at Laplace, Louisiana, for
making aramid ingredients.16 The buildup will increase capacity in the rein-
forcement grade (Kevlar 49) from 1800 to 5445 metric tons over the 3-year
period.
The introduction of carbon fibers on a large scale in the aircraft indus-
try may give a big additional boost to the acceptance of carbon reinforcements
in plastics in many industries.19 Lear Aviation Corporation is developing a
prototype of a private business airplace that will be made almost entirely
from carbon fiber reinforced plastic. The current price of carbon fibers is
expected to be cut in half in the near future. Production is increasing as
shown by Hercules, Inc., which now has a 90 metric ton/yr carbon capacity at
Magna, Utah, and plans to expand to 205 metric ton/yr by 1980.19 Union Carbide
has produced a new pitch-based carbon fabric for stampable thermoplastic auto-
motive parts.
Increased usage of wollastonite as an asbestos substitute is also antici-
pated. Jim Walters Resources, Inc. reports a growing list of customers in
the processed mineral fiber market. A solid indication of the growth of pre-
compounded mica-reinforced thermoplastics is the number of companies offering
such materials, including Washington Penn Plastics, Fiberfill, Thermofill, A.
Schulman and Ecoplastics, Ltd. of Canada.22
Despite the high-heat performance and mechanical properties provided
by asbestos, the Rogers Corporation intends to phase out the use of asbestos as
quickly as asbestos-free alternatives gain customer acceptance. They are cur-
rently searching for alternatives to all their asbestos products and report
that successful substitutes are currently available for asbestos in general
purpose phenolic compounds, although they do not manufacture such. Rogers
manufactures only specialty thermoset compounds. They report successful sub-
stitution for asbestos in many, but not every instance.1'3'25 Rogers Corpora-
tion has developed new glass and combination glass and cellulose reinforced
products which have similar properties to asbestos-reinforced phenolics.5
These products are being considered for several large volume programs although
the asbestos substitute materials do not currently replace any asbestos products.
Rogers reports that acceptance of such a substitution in the marketplace is not
assured, since the cost of new products is higher (up to 15 percent) and molding
characteristics are not always identical. A research breakthrough in 1978
created Roger's GP/duroid (gasketing material) products containing no asbestos,
but with essentially equivalent heat resistance and sealing characteristics.
Introduction of this new class of materials is now underway.26 In addition,
DAP (diallyl phthalate) molding materials, made with asbestos fibers in the
past, are now being produced with other reinforcements.
Apparently there are some specialty products where no feasible asbestos
substitutes have been found. The Rogers Corporation has reported that the
phenolic molding materials used in commutators and rotors in electrical and
automotive applications currently are reinforced with asbestos. These products
function in a very dynamic environment where temperatures of 177°C and 30,000
26.1
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rev/min prevail. Asbestos provides the heat resistance, dimensional stability,
and moldability necessary for these applications. In their experience, no
substitute for asbestos fiber exists for these applications.
Nonetheless, with the exception of specialty applications, phenolic sup-
pliers have replaced or are in the process of substituting asbestos with other
materials. Asbestos-free phenolic compounds exhibit nearly identical proper-
ties (90 to 98 percent as good, according to one supplier) at nearly identical
cost.8 It may be that asbestos will remain a reinforcement material in only
specialty applications, providing exposure can be controlled to within accept-
able limits. With demands of higher specifications by purchasers.in the future,
asbestos substitutes cannot merely equal asbestos, but must be developed to
exceed the properties of asbestos reinforcement.22
CONCLUSION
Asbestos has been used as a reinforcing material in phenolic molding com-
pounds because of its good physical properties which impart a good surface
finish, toughness, resistance to heat and fire, minimal shrinkage and warpage,
in addition to good reinforcing properties. Not every molded product
requires all of the physical properties supplied by asbestos and consequently
substitutes which lack some physical properties but which meet product specifi-
cations can replace asbestos. However, a majority of the products currently
reinforced with asbestos require all the above-mentioned properties which
asbestos supplies. In these instances, the substitute material must supply
physical properties which are equal to or greater than the asbestos it replaces.
New fiber technology has been developed which has boosted physical properties
of substitutes such that they are comparable to asbestos. In addition, manu-
facturers have blended various reinforcements to achieve required properties.
If the thermal insulation or tensile properties of asbestos are necessary,
replacement sometimes requires using several materials together, such as a
mixture of mica and an organic material. Where these special properties are
not necessary, organic fillers may be used which are often cheaper than
asbestos. Manufacturers often look for products with greater reinforcing and
insulating properties than asbestos, due to increased demand for high-
99
performance materials by industrial users.
There is a well-established trend throughout the reinforced plastics in-
dustry to replace asbestos with alternative materials. These materials
include:
• Fibrous glass
• Clay
• Talc
» Mica
• Wollastonite
o Processed mineral fiber
• Carbon fibers
• Aramid fibers
262
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Polyethylene fibers may also be developed for future use in phenolics.
In some cases it appears that these materials may even be used at a cost com-
parable to asbestos, while exhibiting similar properties, when blended with
appropriate additives. However, no one substitute material acting alone can
completely replace asbestos, and there are still some specialty products where
no feasible asbestos substitutes have been found. In general, reinforced
plastics appear to have progressed towards the replacement of asbestos. The
process of converting to nonasbestos alternatives will continue in the area
of phenolic molding compounds.
263
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REFERENCES
1. Meylan, W. M., et al. Chemical Market Input/Output Analysis of Selected
Chemical Substances to Assess Sources of Environmental Contamination:
Task III - Asbestos. EPA 560/6-78-005. August 1978.
2. Cogley, D., et al. Life Cycle of Asbestos in Commercial and Industrial
Use Including Estimates of Release to Air, Water and Land, prepared by
GCA/Technology Division for EPA. October 1979.
3. Lee, Robert, Rogers Corp., Rogers, CT. Correspondence concerning GCA's
Draft Report sent to Mr. Larry Longanecker, U.S. EPA, September 8, 1981.
4. Exner, P. Trip Report to Rogers Corporation, Manchester, CT. GCA,
October 30, 1979.
5. Telecon. Vincent R. Landi, Rogers Corporation with R. Bell, GCA
Corporation/Technology Division. February 5, 1980.
6. Clifton, R. A. Preprint from the 1980 Bureau of Mines Minerals Yearbook
on Asbestos, p. 4.
7. Telecon. Jerry Killner, Plastics Engineering with R. Bell, GCA
Corporation/Technology Division. February 8, 1980.
8. Naitove, M. H. Speech presented at EPA/CPSC Substitutes to Asbestos
Conference, Arlington, VA. July 14-16, 1980.
9. The Asbestos Controversy Continues, Plastics Design Forum. Nov./Dec.
1978.
10. U.S. Bureau of Mines, Mineral Industry Surveys, Asbestos in 1976, by
R. A. Clifton.
11. U.S. Bureau of Mines, Mineral Industry Surveys, Asbestos in 1978, by
R. A. Clifton. August 22, 1979.
12. Telecon. B. Colclough, Fiberite Corp. with R. Bell, GCA Corporation,
February 1980.
13. A. S. W., More Muscle, Higher Heat: They Power a Phenolic Molding
Compound 'Revival.1 Modern Plastics. July 1979.
14. General Electric Product Brochure, Genal GF-7000 Series.
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15. Seymour, R. B. (1979). Fibrous Reinforcements for Plastics. 1979
Modern Plastics Encyclopedia, 170-174.
16. Telecon. Mary Ann Atchley, DuPont, Wilmington, DE, with R. Bell,
GCA Corporation, February 1980.
17. Engineering Thermoplastics: Basic Performance Materials of the
Future, Modern Plastics. May 1979.
18. Telecon. Roger Porter, University of Massachusetts with R. Bell,
GCA Corporation/Technology Division. February 6, 1980.
19. Additives: Resin Squeeze Will Make Them More Profitable, More
Useful. Modern Plastics. May 1979.
20. Fillers and Reinforcements, Modern Plastics, July 1979.
21. Telecon. Donald Randolph, U. S. Gypsum with R. Bell, GCA Corporation/
Technology Division. February 6, 1980.
22. Plastics and Floor Tiles Roundtable Discussion, at EPA/CPSC Substi-
tutes to Asbestos Conference, Arlington, VA. July 14-16, 1980.
23. Telecon. Sales Manager, General Electric Co., with R. Bell,
GCA Corporation, February 1980.
24. Telecon. Keith Smith, Hooker Chemicals and Plastics Corporation,
Durez Division with R. Bell, GCA Corporation/Technology Division.
February 1, 1980.
25. Telecon, J. Ellis, Plastics Engineering, with R. Bell, GCA Corporation,
February 1, 1980.
26. Rogers Corporation Annual Report 1978.
265
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SECTION 10
TEXTILES
ASBESTOS PRODUCT
Special Qualities
The specific asbestos textile products discussed in this section include:
• Fire-Resistant Materials*
• Thermal Insulation,
• Electrical Insulation,
• Packings and Gaskets,
• Friction Materials, and
• Specialty Textiles.
The strength of asbestos allows it to be processed into textiles using
looms and other equipment commonly employed in the textile industry.1 Asbestos
is fireproof, thermally nonconductive, strongly dielectric, moisture, abrasion,
and corrosion resistant, chemically and dimensionally stable, and flexible.
In addition, asbestos is one of the few materials complying with military
specifications.^
Product Composition
Asbestos used in 1980 for textiles was 200 metric tons of grades 1 and 2
chrysotile and 1700 metric tons of grade 3 chrysotile, or a total of 1900
metric tons, down from 2900 tons in 1978.2
*Defined as combustible but self-extinguishing materials.
At the Asbestos Textiles Roundtable Discussion of the EPA/CPSC Substitutes
for Asbestos Conference (Arlington, Va., July 14 to 16, 1980), one party felt
that asbestos was the only material to pass these specifications while a
second party (from the Navy Department) stated that high temperature silica
products are actually better than asbestos, having a higher temperature capa-
bility and equal durability. A substitute such as Nextel® (a 3M product) when
used as a hybrid has not passed the military test.
266
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The different forms of asbestos textiles used for the six aforementioned
textile products are given in Table 71.
TABLE 71. FORMS OF ASBESTOS TEXTILES USED IN ASBESTOS PRODUCTS
Fire-
resistant
Yarn
Thread
Cloth
Thermal
insulation
Yarn
Cloth
Cord
Rope
Tape
Tubing
Electrical
insulation
Yarn
Roving
Tape
Thread
Felts
Cord
Lap
Tubing
Packings
and Friction
gaskets materials
Yarn Yarn
Rope Cloth
Wick
Cord
Cloth
Tape
Specialty
textiles
Fiber
Asbestos yarn is composed primarily of asbestos fibers (75 to 100 percent),
Cotton, nylon, polyester, and wire are added for reinforcement in some applica-
tions of yarns. Asbestos yarns are made in all of the standard ASTM grades
shown in Table 72.
TABLE 72. ASBESTOS TEXTILE GRADES3
Grade'
Asbestos content by weight
Commercial
Underwriters'
Grade A
Grade AA
Grade AAA
Grade AAAA
75% up to but not including 80%
80% up to but not including 85%
85% up to but not including 90%
90% up to but not including 95%
95% up to but not including 99%
99% up to and including 100%
Asbestos textile grades differ with each
asbestos textile form.
Asbestos thread is produced in both plain (nonmetallic) and metallic
(wire inserted) classes (A and B), the latter being noted for its great
tensile strength and high thermal stability. Asbestos thread is generally
furnished in Underwriters' grade.
267
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Asbestos cloth is woven from five classes of asbestos yarns. The most
widely used fabrics are woven from Class A (plain or nonmetallic) yarns and
Class B (metallic or wire inserted) yarns. Other fabrics are made from Class
C, D and E reinforced yarns. The different classes of asbestos cloth are
listed below:
• Class A—Cloth constructed of asbestos yarns containing no
reinforcing strands.
• Class B—Cloth constructed of asbestos yarns containing
wire reinforcing strands.
• Class C—Cloth constructed of asbestos yarns containing
organic reinforcing strands.
• Class D—Cloth constructed of asbestos yarns containing
nonmetallic inorganic reinforcing strands.
• Class E—Cloth constructed of two or more of the yarns
used in both Classes A through D.
Asbestos cord is manufactured in all standard ASTM grades. The diameters
of asbestos cord range from 0.15 cm (0.06 in.) to 0.97 cm (0.38 in.). Asbestos
rope is available in commercial grade for most general uses and in Underwriters'
AA, AAA, and AAAA grades depending on service requirements. Tape is manufactured
mainly as plain or nonmetallic tape and as a wire inserted product; those used
in thermal insulation are manufactured in all of the standard ASTM grades.
Asbestos tubing also comes in all of these grades; roving is blended with cot-
ton or other organic fibers, producing various degrees of density to meet
specific requirements of the user. This is also applied in the five standard
ASTM grades. Asbestos lap comes in two styles: one is a single ribbon-like
formation of fibers and the other a paralleled assemblage of the first. It
comes in A, AA, and AAA grades. Felts come in all grades and are available
both with or without glass cloth reinforcement; they are produced in sheets,
tapes, and rolls. Wick is usually of commercial grade but other grades can
be supplied on order.
Uses and Applications
Asbestos fire-resistant materials are used in a variety of applications,
including welding curtains, draperies, blankets, protective clothing, hot con-
veyor belts, furnace shields and molten metal splash protection aprons.3 In ad-
dition, asbestos fire-resistant materials are used in the construction field as
temporary blankets or curtains. Further, they are used in the military, fire-
fighting and aerospace fields for protective clothing and in various rocket and
missile parts. Ironing board covers and theater curtains also contain these
materials.
Asbestos textiles are used as thermal insulation in pipe wraps for safety
protection; stress relieving pads in welding operations; protective coverings
for hot glassware utensils such as pincers and tongs; coverings for diesel
engine exhaust lines; flue sleeves; and braided walls in the construction of
steam hoses.2
268
-------
Asbestos textiles are employed for the insulation of wires and cables,
especially those which are designed for low voltage, high-current use under se-
vere temperature conditions. They are also used for insulation of arcing bar-
riers in switches, circuit breakers, heater cords, and motor windings, and as
sleevings for electrical appliance leads and insulated conductors where fire
protection and resistance to mechanical abrasion are needed.
Asbestos textiles are used for pump packings; all purpose shaft and valve
stem packings; expansion joints; manhole gaskets; seals for boilers, ovens, and
furnaces; flange gaskets; and gaskets for storage tanks, cookers, and dryers.
The applications of woven asbestos brake linings are mainly found in in-
dustrial band and drum brakes contained in cranes, lifts, excavators, winches,
concrete mixers and mine equipment. Woven asbestos may be used as clutch
facings for industrial band, plate and cone clutches in cranes, lifts, excava-
tors and winches. Automotive brake pads can use a woven asbestos cloth which
may be reinforced with brass wire or impregnated with phenolic resin, as is
commonly used in clutches.1*
Asbestos carded fiber is the main form of asbestos textiles that can be
used in specialty products. Carded fiber is used mainly in liquid filters for
such products as beer, wine, oils and chemicals; and in electrolytic diaphragms.
It is also used as wiping pads for molten metal and as stuffing box packing.
Product Manufacturing
Manufacturing Process —
There are two basic variations employed in asbestos textile manufacturing:
the conventional and wet processes. The former process employs either the dry
or damp method. These two methods are identical except that during the damp
method the yarn is moistened either by contact with water on a roller or by a
mist spray. Most textiles are manufactured by the conventional process.
In the conventional process, raw asbestos fibers of various grades are
blended and mixed, with the composition of the blends and fixing of the
formulation governed by the fiber characteristic, manufacturing and finished
product requirements and intended use. 3 The different grades received are
moved to the rear of the blender. Selected fiber sizes then enter a hopper.
When filled, the hoppers deliver the blended material to the carding operation.
The carding operation combs the fibers with a relatively parallel arrange-
ment called a fiber mat. This mat is pressed and layered into a lap. The lap
is separated into thin, continuous ribbons called roving. Cotton, rayon or other
material may be added at this stage to strengthen the roving.
Roving, which has been mechanically twisted and spun to give it tensile
strength, forms a single yarn. This yarn may be twisted with other single yarns,
wire or other material to produce plied yarn which can be coated to produce
thread or treated yarns.
269
-------
The wet process is based on forming single filament fibers by extrusion.
The process consists of making a gelatinous mixture of fine asbestos fiber in
water with a volatile dispersant. The mass is extruded through small dies.
The extruded thread is then spun into various products. The product tends to
hold asbestos fibers better than those produced by the conventional pro/cesses,
thus reducing workplace fiber levels, but the yarn formed has the disadvantage
of poor absorption and impregnation characteristics.
Asbestos tubing is made from asbestos yarns, either braided or woven. The
braided style is supplied in many diameters and textures and in several wall
thicknesses to meet a variety of service conditions. It can be treated as
required. The woven style is manufactured in various constructions depending
on specifications.
Asbestos tape is a narrow woven fabric manufactured from plied yarn
containing salvage edges (the edge of the woven fabric finished to prevent
raveling). The method of manufacturing tape depends on the class specified.
Asbestos rope is produced in two styles: twisted and braided. Twisted
asbestos rope is made by twisting two or more strands of asbestos wick
tightly together. Heavier ropes contain a binder to hold the twist.
Braided asbestos rope is manufactured in three constructions: (1) by
braiding one or more jackets of asbestos yarn over a case of asbestos rope
or wick; (2) by braiding asbestos yarn braid over braid; and (3) by plaiting
asbestos yarn into square cross section.3
Asbestos cord is usually twisted asbestos yarn (a predetermined number)
of strands) which forms a cord of desired diameter and tensile strength.
The yarns used may be sized or unsized, plain or metallic (wire inserted),
or single or plied depending on the end use of the product.3
Asbestos textile! packing is manufactured from a dry asbestos yarn that is
coated with a lubricant. The impregnated yarns are braided into continuous
lengths of packing and a second impregnation may follow. Variations of braided
packing can be made by extruding a mixture of asbestos fiber, binder and lub-
ricants, and then braiding lubricating asbestos yarns over the extrusion. The
amount and type of lubricant and binder used in these processes varies. The
formed product may then be coiled, boxed and sold. Yarn may also be used as
reinforcement to elastomers such as rubber, and molded to desired shapes.^
Asbestos wick is manufactured by loosely twisting together several strands
of roving, tubing or felted asbestos.3
In most cases, asbestos textile materials are bound or coated with resins
or elastomers before becoming the final product. The materials can also be
aluminized to give a heat reflecting surface. The metallic layer can be
sprayed or bonded to the cloth by a thermosetting resin.
The manufacturing process as well as the available substitutes for woven
textiles used in friction materials are discussed in the Friction Materials
category of this report.
270
-------
Name and Number of Manufacturers—
There are three main companies which manufacture asbestos textiles used
in fire-resistant materials, electrical and thermal insulation, and specialty
textile products. Secondary manufacturers receive asbestos textiles in the
form of yarn to manufacture the final product. Primary manufacturers are
listed below.1
• Raybestos Manhattan Inc. North Charleston, NC
Marshville, NC
• Southern Textiles Corporation Charlotte, NC
a subsidiary of H.K. Porter
Co., Inc., Pittsburg, PA
• Amatex Corporation ' Norristown, PA
Meredith, NH
These three companies, and a fourth—Johns-Manville Corporation, of Manville,
NJ—also manufacture asbestos textiles for packings and gasket products.
Production Volumes—
In 1980, the U.S. asbestos consumption by end use for textiles was 1900
metric tons, the majority of this total being grade 3 of the chrysotile type
(1700 metric tons).2
Asbestos used in electrical insulation materials amounted to 8900 metric
tons in 1980.2 This asbestos fiber was used mainly in the forms of paper,
roving, webbing and braid where comparatively high temperatures may occur.
In 1980, the volume of asbestos used for thermal and electrical insulation
materials amounted to approximately 2.5 percent of the total U.S. output of
asbestos. The production volumes for individual asbestos textiles used in
electrical insulation are not available.
SUBSTITUTE PRODUCT
Methodology
Search Strategy—
The search strategy included a combination of a literature review and
a telephone survey of industry representatives to gather data on product
specifications, uses, prices, and market trends.
Summary of Contacts—
The following company representatives were contacted for information
regarding fire-resistant material substitutes.
• Mr. Bill Timmons
Marketing Supervisor of Industrial Products
Celanese Plastics and Specialties
Chatham, NJ
(201) 635-2600
271
-------
• Mr. Bal Dixit, President
Newtex Industries, Inc.
Victor, NY
(716) 924-9135
• Ms. Kathy Pietak
Textile Specialist
The Carborundum Company
Niagara Falls, NY
(716) 278-2000
• Mr. Bob Wilander
Sales Manager
Westex, Inc.
Chicago, IL
(312) 523-6351
• Mr. Marion Black
Marketing Manager
Hitco Materials Division
Gardena, CA
(213) 321-8080
• Mr. Barry Reznik
Manager
Cotronics Corporation
Brooklyn, NY
(212) 646-7996
• Mr. Richard Saffadi
President
Alpha Associates, Inc.
Woodbridge, NJ
(201) 634-5700
• Mr. Edmund Fenner
Director of Environmental Services
Johns-Manville Corporation
Denver, CO
(303) 979-1000
• Ms. Lucille Ellingson
Sales
3M Company
St. Paul, MN
(612) 733-1558
• Mr. Bob Chiostergi
Textile Sales
E.I. Dupont de NeMours and
Company, Inc.
Wilmington, DE•
(302) 999-3951
272
-------
• Mr. Bill Maaskant
Marketing Manager
Amatex Corporation
Norristown, PA
(215) 277-6100
• Mr. Michael Storti
Marketing Manager
American Kynol, Inc.
New York, NY
(212) 279-2858
• Mr. Joseph Angelina
Textile Products Marketing Manager
Garlock, Inc.
Palmyra, NY
(315) 597-4811
• Mr. K. C. McCallister
Marketing Manager
Mr. A. Fazia
Market Development Manager
Celanese Fibers Marketing Company
Charlotte, NC
(704) 554-2735
• Mr. Robin Vance
Vice President
Fire Safe Products, Inc.
St. Louis, MO
(314) 423-6989
Fiber Substitutes
Special Qualities— :
Fiber substitutes available in all textile applications include:
• fiber glass,
• ceramics,
• organics,
• graphite,
e carbon,
• quartz,
• cotton, and
• special wool blends.
Physical and chemical properties of these high temperature materials are com-
pared in Tables 73 and 74 along with properties of asbestos.
273
-------
TABLE 73. ASBESTOS AND SUBSTITUTE FIBER PROPERTY COMPARISON FOR TEXTILE PRODUCTS
to
Material
(Manufacturer)
Asbestos
Glass
Texo™, and other Fiber
Glass Yarns
(PPG Industries)
Zetex™
(Newtex Industries, Inc.)
Ceramics
(3M Company)
Refrasil
(Hitco Materials)
Organics
Nomex
(DuPont Co.)
Kevlar®
(DuPont Co.)
Teflon®
(DuPont Co.)
Product
application
All applications requiring
an incombustible high
temperature fabric .
All applications requiring
an incombustible high
temperature fabric.
Fire-resistant materials;
thermal insulation; packings
and gaskets.
Fire-resistant materials;
thermal and electrical
insulation; packings and
gaskets .
All applications requiring
an incombustible high
P
thermal and electrical
insulation, packings and
gaskets.
Fire-resistant materials;
thermal and electrical
Insulation; packings and
gaskets.
Fire-resistant materials;
thermal and electrical
insulation packings and
gaskets.
Fire-resistant materials;
friction materials; cables.
Fire-resistant materials;
thermal and electrical
insulation; packings and
gaskets.
Temperature
resistance3
up to °C (°F)
649C
(1200)°
538
(1000)
340d
(650)d
1538
(2800)
1427
(2600)
(2600)
928
(1800)
371
(700)
204
(400)
316
(600)
Tensile
strength
kPa (psi)
5.68 x 106
(824,000)
2.17 x 10E
(315,000)
2.0 x 106e
(200-
300, 000 )e
3.44 x 106
(500,000)
high
(250,000)
5.17 x 10s
(75,000)
6.89 x 105
(100,000)
2.76 x 106
(400,000)
3.62 x 10s
(52,500)
Properties
Comments
Low thermal conductivity; excellent radiation
stability; good flexibility; excellent resistance
to moisture and corrosion; excellent spinhability ;
contains a minimum of magnetic or conductive fibers.
Density similar to asbestos; excellent handling
characteristics; high dielectric strength; not as
durable as asbestos; may produce some skin
irritation; fiber diameter 0.066 mm (0.0026 inch).
Dimensional stability - no more than 3X elongation'
under maximum stress, chemical resistance, high
thermal conductivity, low moisture absorption,
high dielectric strength, flame resistance.
Excellent strength and durability; excellent
dielectric strength; dimensional stability, excellent
cutting, sewing and handling; abrasion-resistant;
fiber size ^9 microns; lower (less than one-half)
thermal conductivity than asbestos.
A high tensile strength silica - alumina fiber;
flexible; abrasion-resistant
resistant (after 4 hours at 816°C (1500°F), it retained
100 percent of its strength); good flexibility; some
skin Irritation; fiber size 10 to 12 microns in
diameter.
Good acid resistance; good dielectric properties;
excellent resistant to thermal shock; high capacity
to. absorb moisture; lacks abrasion resistance,
fiber diameter 8 to 12 microns.
Abrasion- resistant; flexible; radiation-resistant;
chemical-resistant; washable; low shrinkage.
High thermal stability; excellent chemical
resistance; excellent cut resistance; low thermal
conductivity.
High chemical resistance; low friction and adhesion;
low shrinkage; great flex-abrasion resistance;
radiation- resistant .
References
2
2,6
7
8,9
6
12,13
14,15
15,16
15,16
(continued)
-------
TABLE 73 (continued)
Oi
Material
(Manufacturer)
Kynol
P.B.I.™
(Celanese Plastics and
Specialties Co. )
Fiberf rax "
(Carborundum Co.)
Carbon
Celion
(Celanese Plastics and
Specialties Co.)
Celiox™
(Celanese Plastics and
Specialties Co.)
Quartz
Alphaquartz
(Alpha Associates)
Cotton
(Westex, Inc.)
Product
application
Fire-resistant materials;
Fire-resistant materials.
thenaal and electrical
insulation; packings and
gaskets.
Fire-resistant materials;
packings and gaskets;
friction materials.
packings and gaskets.
Fire-resistant materials.
thermal and electrical
insulation; packings and
gaskets.
Fire-resistant materials.
Temperature
resistance
up to =C (°F)
704'
(1300)1
500
(932)
1260
(2300)
1427
(2600)
5432
(3000)
(no oxygen)
760
(1400)
Over
1204
(2200)
232
(450)
Tensi le
strength
kJ>a (psi)
1.86 x 10-
(27,000)
2.07 x 106
(300,000)
1.72 x 106
(250,000)
Over
3.10 x 106
(450,000)
3.24 x 10'
(470.000)
2.10 x 10s
(30,500)
8.69 x 105
(126,000)
8.62 x 10s
(125,000)
Properties
Comments References
Low noiszure absorption; acid-resistant; low toxic 3,17,18
off gases; low shrinkage; is a carbon precursor;
low abrasion.
Polybenzinicazole; nonflammable in air; little or no 19,20
eraittance o: toxic off gases; acid-resistant;
readily processed on conventional textile equipment;
comfortable; good cryogenic characteristics; high
moisture regain.
Chemical-resistant; low thermal conductivity; 21,22
resists oxidation and reduction; excellent resist-
ance to thermal shock.
High flexibility, lightweight, good retention of 6,21,22
fiber properties at high temperatures.
Flexible, low shrinkage; excellent oxidative 21 ,22
stability; excellent adhesion to organics;
excellent electrical/thermal conductivity.
Lightweight, flexible, high moisture regain, low 23,25
density, readily converted into carbon
Thermal stability; elastic; excellent resistance 26,27,28
to thermal shock; easily impregnated; excellent
abrasive characteristics; high purity; transparency
to electromagnetic and radio waves.
Flame-resistant; is coated and treated; washable; 29
fiber diameter 0.020 to 0.030 mm (0.0008 to
0.0011 inches).
Temperatures depend upon product application.
Figures are for fibers only, and are not necessarily related to fabric strength.
CWire inserted asbestos textiles.
Retains 50Z of tensile strength at this temperature.
6At 72°F and 50% R.H. based on fiber area.
Carbonizing temperature range.
-------
TABLE 74. CHARACTERISTICS OF HIGH TEMPERATURE MATERIALS
30
to
Property
Maximum Continuous
Use Temperature (°C)
Degradation
Temperature (°C)
Cloth Tensile
Strength (Ibs)
Fiber (tensile)
Strength (MN/m2)
Fiber Diameter
(urn)
Fiber Length
(mm)
K value in Btu
in./hr ft2 °F
Chemical Resistance
Chrysotile
asbestos
cloth
600
up to 1700
50-200
3100 average
Fiber 0.03-100
Fibril 0.02
Fiber 1-80
Fibril 0.25-5
0.7 at 212°F
Most chemicals
Exceptions:
HF, strong
acids at
elevated
temperatures
Fiberglass
cloth
538
700-760
melting point
500-600
1700
14.7
152-254
0.51 at 500°F
Most chemicals
Exceptions:
HF, phosphroic
acid, strong
alkalies
Alumino-
silicate
products
1260
1790
melting point
65-100
2760
2-3 average
40-250
0.40-0.70
at 500°F
Most chemicals
Exceptions:
HF, H3POi,,
strong
alkalies
Aluminum
borosilicate
cloth
593
1145
melting point
500-600
3447
9
continuous
filament
0.42 at 500°F
Most chemicals
Exceptions:
HF, HaPOi,,
strong alkalies
Aromatic
polyamide
cloth
-
-
-
-
-
*-
0.45 at 500 °F
Most commonly
used chemicals,
solvents
Exceptions:
strong acids
and alkalies
-------
Product Composition—
The specific compositions of the fiber substitutes are listed in conjunc-
tion with the manufacturing process section.
Another potential substitue should be noted for this category. Fibercoat
by Textured Products was specifically developed for use as fireproof upholstery
and wall covering fabrics. As this product is noted for many applications, it
was covered extensively in the Paper section "Electrical Insulation: and should
be referred to there by the reader.
Uses and Applications—
At a recently held conference concerned with the availability of sub-
stitutes for various asbestos products, a supplier of asbestos-free textiles
stated, ". . . It is very safe to say that there is a replacement for every
asbestos textile product right now."31 In general, replacement of asbestos
must be made on an application-by-application basis, taking into consideration
such factors as cost, performance, and service life.'
Asbestos thermal insulation, which is used principally for its heat
resisting properties, can be replaced by fiberglass for the lower range of
temperature conditions [up to 540°C (1000°F)], or by ceramics over higher
ranges.1 High strength is not usually a critical thermal insulation
requirement.
In applications such as electric insulation sleeving for cables and
battery separators, direct replacement with fiberglass is usually satisfac-
tory; fiberglass is not suitable for applications where severe flexing is
involved. For cable and wire insulation up to 530°C (990°F), ceramic mate-
rials may be used with glass filament inserts, to maintain high temperature
strength.3 Quartz products also can be substituted for asbestos in electrical
insulation at elevated temperatures.
Manufacturing Summary—
Manufacturers—Manufacturers of nonasbestos textile materials are listed
in Table 75. In addition, Table 75a provides a list of weavers and fabricators
of one substitute product—Fiber Glass Yarn—and which product type(s) each makes;
i.e., industrial tapes, fabrics, etc.*
*For completeness, gaskets and packing products were included on this list,
and referenced here in the gaskets and packings section of this report.
277
-------
TABLE 75. MANUFACTURERS OF NONASBESTOS TEXTILE FIBERS'
Manufacturer
Location
Fiber produced
Owens-Corning
Hitco Materials Division
Newtex Industries, Inc.
PPG Industries
3M Company
Carborundum Co.
Celanese Plastics and
Specialties
Alpha Associates, Inc.
E.I. DuPont de Nemours
and Co., Inc.
American Kynol Inc.
Westex, Inc.
Toledo, OH
Gardena, CA
Victor, NY
Pittsburgh, PA
St. Paul, MN
Niagara Falls, NY
Chatham, NJ
Woodbridge, NJ
Wilmington, DE
New York, NY
Chicago, IL
Fiber glass
®
Fiber glass (Refrasil )
Fiber glass (Zetex™)
Fiber glass (Texo™)
®
Ceramic (Nextel 312)
®
Ceramic (Fiberfrax )
TM
Carbon (Celiox )
Carbon (Celion®)
Organic (PBI™)
Quartz (Alphaquartz )
Organic (Nomex®, Kevlar®,
Teflon®)
Organic (Kynol™)
Cotton
From telephone contact and product literature.
278
-------
TABLE 75a. WEAVERS AND FABRICATORS OF TEXTURED AND OTHER FIBER GLASS YARN PRODUCTS7
Asbestos replacement
General Specialty Electrical Ropes,
industrial Industrial industrial sleeving tapes. Fiber glass Vinyl-coated packings Tapes and
fabrics tapes fabrics cordage screening yarns Fabrics and gaskets tubing
Amatex Corporation, • • • •
Norristown, PA
Auburn Manufacturing Co., •
Mechanic Falls, HE
Atkins & Pearce Company, •
Cincinnati, OH
fiaycor, • •
Atlanta, GA
Belding Corticelli Fiber «
Glass Fabrics,
New York, NY
Bentley-Harris Mfg. Co., • • •
Thermal Design Group,
Lionville, PA
Burlington Class Fabrics Company, • • •
A Division of Burlington
Industries,
Rockleigh, NJ
Carolina Narrow Fabric Company,
1^) Winston-Salem, NC
rjj CHEMFAB-Material Technologies
Division,
North Bennington, VT
Clark-Schwebel Fiber
Glass Corp.,
White Plains, NY
Darco-Southern, Inc.,
Independence, VA
Davlyn Manufacturing Co., Inc.,
Chester Springs, Pa.
Engineered Yarns, Inc.,
Coventry, RI
FIL-TEC, Inc.,
Hagerstovm, MD
Garlock, Inc.,
Palmyra, NY
Hi Temp Textiles,
Greensboro, NC
Hesgon Company,
Brownsville, TX
Hexcel Corporation-Trevano Div.,
Dublin, CA
Intec, Inc.,
Buena Park, CA
(continued)
-------
TABLE 75a (continued)
Asbestos replacement
S3
00
o
General Specialty Electrical Ropes,
Industrial Industrial industrial sleeving tapes, Fiber glass Vinyl-coated packings Tapes and
fabrics tapes fabrics cordage screening yarns Fabrics and gaskets tubiDŁ
Mutual Industries, Inc. • • •
Philadelphia, PA
Newtex Industries, Inc., • • •
Victor, XY
North American Textiles, • •
Detroit, MI
Oxford Mills, A Div. of Root • •
Industries,
Mt. Wolf, PA
Phifer Wire Products, Inc., • •
Tuscaloosa, AL
Quinco Fabrics, Inc., •
Auburn, ME
Raybestos Industrial Products. • • • •
North Charleston, SC
I. Sonuners Narrow Tape Corporation, • •
East Stroudsburg, PA
Southern Textile Corp., • • x • • •
Charlotte, NC
J.P. Stevens & Company, • •
Glass Fabrics Dept.,
New York, NY
Johnathan Temple, Inc. «
Hackensack, NJ
Uniglass Industries, Div. « ^
of United Merchants, Inc.
New York, NY
Warwick Mills, Greenville Mill
Div., New Ipswich, NH •
-------
Manufacturing process—The manufacturing processes used to form some of
the nonasbestos textile materials are listed below.
• Fiber Glass—manufactured from a silica-based product that is
carded and formed into yarns. These yarns are sold to
secondary manufacturers who may impregnate or chemically and
physically alter the fiber glass according to their customers'
needs.32 An example of product composition of an "E" (elec-
trical) glass form is given in Table 75b, based on percent by
mas s:
TABLE 75b. COMPOSITION OF E-GLASS FIBER SUBSTITUTE7
Silica 54.0%
Calcium oxide 20.5%
Alumina 14.0%
Boron oxide 8.0%
Soda 1.0%
Calcium fluoride 1.0%
Magnesia 0.5%
Total minor oxides 1.0%
Bare glass composition 100.0%
Plus binder 0.5-2%
Refrasil"—manufactured by leaching out the low melt elements
(such as sodium, potassium, boron, lithium) from fiber glass
with hydrochloric acid, and forming silica.12
Zetex—proprietary process; received as a yarn, woven and
treated before becoming a fire-resistant material. No pro-
cess changes required from asbestos textile manufacturing
steps.
Fiberfrax®—carded with an organic carrier such as rayon and
made into various fire-resistant materials.21
Cotton—treated and cured in an ammonia chamber before becoming
a 100 percent durable, flame-resistant fabric.29
*
Quartz—manufactured by processing pure quartz crystals into
extruded filaments which are formed into yarn which is then
plied and woven into fabrics.26
Carbon—manufactured by sintering either rayon or poly-
acrylonitrile fibers to produce extremely strong fire-resistant
fibers.6
281
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* KynoiTfo—a phenol formaldehyde polymer formed as stable fibers
and subsequently cross-linked.6»17
• Teflon®—a perfluorinated polyethylene manufactured by
polymerizing tetraflouroethylene. Teflon particles are
dispersed in a viscous rayon dope and extruded in a rayon
matrix. The rayon is burned off, leaving a continuous
Teflon filament.6'33
• Kevlar®—an aromatic polyamide manufactured by reacting
paraphenylenediamine with phthaloyl chloride.6*16
• Nomex®—an aromatic polyamide manufactured by condensing
metaphenylenediamine with isophthaloyl chloride as a stable
fiber, continuous filament or as short fibers.6
Production volumes—The exact production volumes of some of the textile
materials are proprietary. However, available information is listed in Table 76.
TABLE 76. PRODUCTION VOLUMES OF NONASBESTOS TEXTILE MATERIALS8'12'23'26
Production volume
Manufacturer Substitute kg/yr (Ib/yr)
Celanese Plastics and
Specialties Celion® 45,000 (100,000)
Newtex Industries Inc. Zetex™ 225,000-450,000 (500,000-1,000,000)
Hitco Materials Division Refrasil® 135,000-225,000 (300,000-500,000)
Alpha Associates, Inc. Alphaquartz® 36,000 (80,000)
Product Substitutes
Special Qualities—
Physical and chemical properties of several nonasbestos textiles that are
presently marketed are compared in Table 77.
Product Composition—
The composition of substitute products is included under Manufacturing
Summary.
Uses and Applications—
Discussion of the available substitutes for asbestos textiles used in
packings and gaskets are contained in the Packings and Gaskets category of
this report. This category includes the substitute contacts and manufacturing
summaries, asbestos cost comparisons, current trends, and conclusions.
Substitutes for carded fibers used in liquid filters and electrolytic
diaphragms are discussed in the Beverage Filter and Specialty Papers Sections
of the Paper Products Category of this report. Substitutes for stuffing box
packings are discussed in the Packings and Gaskets category.
282
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TABLE 77. SUBSTITUTE PRODUCT PROPERTY COMPARISON
Properties
S3
00
UJ
Substitute
product
(Manufacturer)
TM
Thermo-Sil
(Oarlock, Inc.)
Product
application
Fire-resistant materials;
thermal and electrical
insulation; packings and
gaskets
Temperature
resistance3
up to °C (°F)
538
(1000)
Tensile
strength
kPa (psi)
2.17 x 106
(315,000)
Comments
Resists organic solvents and most acids and
alkalies; resists abrasion and wear; mois-
ture and weather resistant; dimensionally
stable; high dielectric strength; low die-
lectric constant; soft and flexible.
References
32,34
Durette
(Fire Safe Products, Inc.)
Thermo-Ceram
(Garlock, Inc.)
Norfab
(Amatex Corp.)
SILTEMP
(Haveg Industries, Inc.)
Preox
(Celanese Plastics and
Specialties Co.)
Fire-resistant materials
Fire-resistant materials;
thermal and electrical
insulation; packings and
gaskets
Fire-resistant materials;
thermal and electrical
Insulation; packings and
gaskets
Thermal and electrical
insulation; packings and
gaskets
Thermal and electrical
insulation; packings and
gaskets
593 4.83 x 105 Better heat stability than Nomex ; high 35
(1100) (70,000) abrasion resistance; good acid resistance;
high tear resistance; excellent dimensional
stability.
1260 1.72 x 106 Excellent resistance to mechanical vibration 36
(2300) (250,000) and stress; resists attack from most chemicals;
no loss of strength from water evaporation at
high temperatures; low thermal conductivity
and excellent electrical resistance.
343 — A combination of synthetics, excellent work- 37,38
(650) ability; lightweight; high abrasion resistance;
flexible; good chemical resistance. Amatex
also offers Thermoglass, which will not burn or
smoulder, has excellent dimensional stability,
high tensile strength, chemical resistance, ex-
cellent electrical properties, flexibility, and
meets U.S. Coast Guard Requirements for Incom-
bustible materials and Government MIL specifica-
tions. Applications for such a product include
use as a cloth, tape, tubing and rope.
1649 - Meets MIL Spec 1-24244; approved for use in 39
(3000) nuclear applications; substantial reuse factor
compared to asbestos,
- - Thermally stabilized polyacrylonitrile; flexible; 40
electrically nonconducting; water absorbing;
carbonizes at high temperatures. Emits toxic
cyanide gas at 800°F.: exposure level
undetermined.
Temperatures depend upon product application.
Figures are for fibers only, and are not necessarily related to fabric strength.
-------
Manufacturing Summary—
Manufacturers—Manufacturers of nonasbestos textile products are listed
in Table 78.
Manufacturing process—The manufacturing processes for some of these
materials are listed below.
• Durette - manufactured by chlorinating woven Nomex fabrics.5
TM
• Thermo-Sil - fabrics and tapes woven, and tubing braided,
from texturized fiberglass yarn. 31f
TM
• Thermo-Ceram - fabrics and tapes are woven, and tubing
braided, from wire-reinforced ceramic yarn, containing a
rayon carrier fiber.36
• Norfab® - manufactured by blending together synthetic fibers
in a unique process. Nor-Fab series 400 is produced as yarn
(plain and reinforced), roving, filler, tapes, braided and
twisted ropes and cord.1*1
Production volumes—The exact production volumes of these products are
proprietary.
COST COMPARISON
Table 79 provides a cost comparison between asbestos fibers and several
available substitutes. There are many substitutes that do not use fiber as a
basic unit of comparison. These include Alphaquartz", Zetex^ , Fiberfrax and
PBI^ . Product cost is a function of both fiber cost and the amount of fiber
required to produce the product. Thus, if a lower weight of a substitute
fiber can be used to produce a product, the substitute product may cost less
than the asbestos product.
Alphaquartz is more expensive than asbestos at $36 to $45/kg ($80 to
$100/lb) for quartz wool and yarn, and $1.20 to $1.50/m1 ($4 to $5/ft) for
quartz mat.26
TM
Zetex is currently more expensive than asbestos at $3.65 to $12.80/m
($4 to $14/yd) or $0.90 to $2.27/kg ($2 to $5/lb) depending on the type of
product required.8 However, production costs are almost identical to asbestos
except in the safety garment field, where they may be higher by about
20 percent.
Fiberfrax® costs $3.50/kg ($7.75/lb) for 1.3 mm (0.5 inch) rope.21
There is a possible market for an organic material called PBI™ which will
cost $9 to $13.50/kg ($20 to $30/lb) for fabric. However, with all factors
284
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TABLE 78. MANUFACTURERS OF NONASBESTOS TEXTILE PRODUCTS32 » 3U > 3S > 37~1*0
to
oo
Manufacturer
Location
Garlock, Inc.'
Celanese Plastics and
Specialties
Fire Safe Products, Inc.
rt
Amatex Corp.
Haveg Industries, Inc.,
a subsidiary of Hercules, Inc.
Southern Textile Corporation,a'b
a subsidiary of H.K. Porter
Co., Inc.
o
Davlyn Manufacturing Co.
FIL-TEC3
Newtex3
Product (or fiber used)
Palmyra, NY
Chatham, NJ
St. Louis, MO
Norristown, PA
Wilmington DE
Charlotte, NC
Chester Springs, PA
Hagerstown, MD
Victor, NY
Fiber Glass (ThermoSil™)
Ceramic (ThermoCeram™) ,
Texo™
(Preox)
Organic (Durette®)
Synthetic (Norfab®) , Texo™
(SILTEMP®)
Glass fabrics, aramid
fibers, Texo™
Texo
TM
Texo
,TM
Texo
,TM
Companies reported by phone contact with Russell Smith,
12/17/81, with N. Krusell, GCA. They produce yarn from
manufactures.
PPG Industries, (Texo™),
Texo fiber that PPG
Asbestos Magazine, March 1981, p. 34.
-------
TABLE 79. COST COMPARISON BETWEEN ASBESTOS FIBERS AND
SUBSTITUTES USED IN TEXTILES3
Approximate cost per
Product kilogram (pound)
Asbestos
Fiber Glass
Texo™
Kevlar®
Nomex
Teflon®
Ref rasil
SILTEMP®
•
Norf ab
Durette
Nextel® 312
TM
Kynol
TM
Celiox
Celion®
Zetex®
$0.45-0.50
(1.00-1.10)
0.50
(1.10)
$0.50-0.85
(1.12-1.87)
2.50-2.70
(5.50-6.00)
2.70-2.95
(6.00-6.50)
3.15-4.50
(7.00-10.00)
3.15-5.40
(7.00-12.00)
2.70-4.95
(6.00-11.00)
1.36-1.82
(3.00-4.00)
3.60
(8.00)
13.50
(30.00)
2.00-2.25
(4.50-5.00)
4.50
(10.00)
11.25
(25.00)
0.90-1.35
(2-5)
Reference
6
6
42
15
15
15
12
39
40
35
10
18
23
23
8
Prices vary with product style and quantity.
The basic yarn prices here vary from $1.29-
1.87/lb for "ETDE" Texo with most less than
$1.50 to a range of $1.12-$1.23/lb for
"6-filament," a coarser and therefore a bit
less expensive product.1*2
286
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considered (the fabric being half the weight of asbestos and possessing a
longer service life) FBI™ could amount to a cost of only three times that
of asbestos.23
CURRENT TRENDS
A downward market is forecasted for asbestos fire-resistant materials.
Many large manufacturers of asbestos fire-resistant materials are currently
manufacturing substitutes such as fiberglass and ceramics along with their as-
bestos products. Many government specifications for fire-resistant materials
are being revised for health reasons, thus encouraging sales of various sub-
stitute products.
Sales of asbestos insulation have dropped drastically from 1973 to 1980.1'2
At current consumption rates, asbestos insulating materials are less than
1 percent in value of the total market for all insulation materials.1 There
is a decreasing trend in the use of asbestos thermal insulation because of
economic as well as health disadvantages.
The low conductivity of substitute electrical textile materials gives
them appreciably better insulating value than asbestos on the basis of both
weight and surface area. Lower densities give these materials further economic
advantages over asbestos. These advantages along with increased health con-
cerns explain the continuing decrease in the use of asbestos for insulating
purposes. Concern with asbestos emissions has prompted many manufacturers
of asbestos textiles used in electrical insulation to turn to viable substi-
tutes such as Fiberfrax", Nomex® and Refrasil®.
Specific trends for some of the nonasbestos textile materials are listed
below.
• Celion", Celiox™ - viable replacement by 1980; potential
450,000 kg/yr; (1,000,000 Ib/hr) plant by 1982.23
TM
• Zetex - high probability of overtaking asbestos market; need
4,500,000 kg/yr; (10,000,000 Ib/yr) plant (300 to 400 workers) to
compete with asbestos.8
• Refrasil" - could replace 27 percent of asbestos market, with
a possible $20,000,000 to $30,000,000 business.12
®
« Durette - by 1990, could have a viable substitute market in
specialized protective clothing.3S
CONCLUSION
There are a number of viable substitutes for asbestos textile materials
that are well suited to replace asbestos in nearly every application.
287
-------
These include: Fiberglass, Kevlar, Nomex, Teflon, Refrasil, Siltemp, Norfab,
Durette, Nextel, Kynol, Celiox, Celion, Zetex, and Fiberfrax. In addition,
other products are still in developmental stages. Many of these substitutes
have better property advantages for textile applications than asbestos. Although
more costly in most cases, these alternatives are already on the marketplace,
providing a nonasbestos choice for consumers. As in the other categories
mentioned where viable substitutes exist, the choice of substitutes involves
consumer education and exceptance towards a changeover from the established
product. As there are some occasions where the substitute products are more
applicable for a particular job, their use may result in longer product life,
leading to lower overall cost and public acceptance. The small number of asbes-
tos textile applications for which no satisfactory alternative exists at present
include lamp and stove wicks, wipes for molten metal, diaphragms for some of
the electrolytic cells and some filter cloths.3
In the future, the market for nonasbestos, fire-resistant materials will
undoubtedly improve. The Department of Interior has projected a zero demand
for asbestos in textiles by the year 2000.^ The performance of high tempera-
ture application substitute materials has proven that these materials not only
compare with, but often exceed the performance characteristics of asbestos.
With the substitute materials currently on the market, and assuming new devel-
opments of asbestos replacement products in the future, asbestos consumption
in fire-resistant materials will drop significantly. Sales of asbestos insula-
tion products have already shown this drop in their drastic decrease in sales
over the past few years.
288
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REFERENCES
1. Meylan, W. M., et al. Chemical Market Input/Output Analysis of Selected
Chemical Substances to Assess Sources of Environmental Contamination:
Task Ill-Asbestos. EPA-560/6-78-005. August 1978.
2. Clifton, R. A. Asbestos 1978. U.S. Department of the Interior, Bureau
of Mines, August 1979, and Clifton, R. A., Preprint from the 1980 Bureau
of Mines Minerals Yearbook.
3. Anon. Handbook of Asbestos Textiles. American Textile Institute. 1967.
4. Michaels, L., and S. S. Chissick, ed. Asbestos: Properties, Applications,
and Hazards. Volume 1. John Wiley and Sons, 1979. p. 305-367.
5. Telecon. Tony Rokos, Amatex Corp., Norristown, PA, (212) 277-6100, with
Anne Duffy, GCA Corporation, GCA/Technology Division, April 16, 1981,
Call No. 19.
6. Sores, Inc., and Arthur D. Little, Inc. Characterization of the U.S.
Textile Markets. Ministere De L1Industrie Et Du Commerce, Government
du Quebec. Final Draft Report. May 1976.
7. PPG Industries Product Information, including "Fiber Glass Yarn Products/
Handbook," and "Texo" Information such as "Texo - The Strong Substitute."
8. Telecon. Dixit, B., President, Newtex Industries, Inc., Victor, NY (716)
924-9135, with T. Henderson, GCA/Technology Division, January 30, 1980.
Notebook No. 07, Phone call No. 11.
9. Newtex Industries Inc. Zetex™ Bulletin. Victor, NY. 1979.
10. Telecon. Ellingson, L. Sales Representative, Ceramic Fiber Products/
3M Company, St. Paul, MN. (612) 733-1558, with T. Henderson, GCA/
Technology Division, January 31, 1980. Notebook No. 07, Phone call
No. 18.
11. Ceramic Fiber Products 3M Company. Nextel® 312 Ceramic Fiber Products.
N-MTDS (79.5) MP, and N-MPBS-(89.5) 11. St. Paul, MN.
12. Telecon. Black, M., Sales Representative, Hitco Materials Division,
Gardena, CA., (213) 321-8080, with T. Henderson, GCA/Technology Division,
January 30, 1980, Notebook No. 07, Phone call No. 11.
289
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13. Hitco Materials Div. Refrasil Product Data Bulletins. P.O. LHT/MD-1779
15 M CP and LHT/MD-275 6M CP. Gardena, CA. November 1979. p. 1-2.
14. E.I. DuPont de Nemours & Co., Inc. DuPont Technical Information Bulletin.
N-236. Wilmington, DE. October 1969. p. 1-12.
15. Telecon. Chiostergi, R., Marketing Manager, E.I. DuPont de Nemours & Co.,
Inc. Wilmington, DE, (302) 999-3951, with T. Henderson, GCA/Technology
Division, February 1, 1980. Notebook No. 07, Phone call No. 20.
16. E.I. DuPont de Nemours & Co., Inc. Characteristics and Uses of Kevlar®
29 Aramid. N-375. Wilmington, DE. September 1976. p. 1-7.
TM
17. American Kynol, Inc. Kynol Novoloid Bulletin. A-10, 003. New York,
NY. October 1974. p. 1-11.
18. Telecon. Storti, M. , Marketing Manager, American Kynol Inc., New York,
NY. (212) 279-2858, with T. Henderson, GCA/Technology Division,
February 1, 1980. Notebook No. 07, Phone call No. 23.
rpiur
19. Celanese Corp. FBI , Polybenzimidazole Fiber. Charlotte, NC.
February 1979. p. 2.
20. Telecon. McCallister, K.C., Marketing Manager, Celanese Corporation,
Charlotte, NC. (704) 554-2000, with T. Henderson, GCA/Technology Division,
February 1, 1980. Notebook No. 07, Phone call No. 22.
21. Telecon. Pietak, K. , Textile Specialist, The Carborundum Company, Niagara
Falls, NY, (716) 278-2000, with T. Henderson, GCA/Technology Division.
January 30, 1980, Notebook No. 07, Phone call No. 08.
22. The Carborundum Company. Fiberfrax Product Bulletins. C736-A-G.
Niagara Falls, NY. p. 1-10.
23. Telecon. Timmons, B. , Marketing Supervisor, Celanese Plastics and Special-
ties, Chatham, NJ. (201) 635-2600, with T. Henderson, GCA/Technology
Division, January 28, 1980. Notebook No. 07, Phone call No. 05.
24. Celanese Plastics and Specialties Co. Celion Carbon Fibers Bulletins.
Chatham, NJ. November 1979.
TM
25. Celanese Plastics and Specialties Co. Celiox Fibers Bulletin. Chatham,
NJ. November 1979.
26. Telecon. Saffadi, R. , President, Alpha Associates, Woodbridge, NJ, (201)
634-5700, with T. Henderson, GCA/Technology Division, January 31, 1980.
Notebook No. 07, Phone call No. 11.
®
27. Alpha Associates Inc. Alpha quartz Bulletins. Data Sheet Nos. 11690-
11693. Woodbridge, NJ. May 1979.
290
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28. Lubin, G. High Silica and Quartz. In: Handbook of Fiberglass and
Advanced Plastics Composites. Reinhold Book Corporation. 1969.
p. 191-200.
29. Telecon. Wilander, R. , Sales Manaher, Westex Inc., Chicago, IL, (312)
523-6351, with T. Henderson, GCA/Technology Division, January 30, 1980,
Notebook No. 07, Phone call No. 10.
30. Hedberg, D. D. Replacements for Asbestos in the Laboratory. March 1980.
31. Manfers, S., Carborundum Corp., speech given at EPA/CPSC Substitutes to
Asbestos Conference, Arlington, VA, July 14-16, 1980.
32. Angelina, J., Textiles Marketing Mgr., Garlock Inc., Palmyra, NY,
(315) 597-4811, with T. Henderson, GCA/Technology Division, February.8,
1980. Notebook No. 07, Phone call No. 11.
33. E.I. DuPont de Nemours & Co., Inc. Properties, Processing and Applica-
tions of Teflon®. TR-2. Wilmington, DE. May 1978. p. 1-15.
34. Garlock Inc. Thermo-Sil™, A Nonasbestos Fabric. LX-7/79-10M.
Palmyra, NY. July 1979. p. 1-6.
35. Telecon. Vance, R., Vice President, Fire Safe Products Inc., St. Louis,
MO. (314) 423-6989, with T. Henderson, GCA/Technology Division,
February 20, 1980. Notebook No. 07, Phone call No. 35.
36. Garlock Inc. Thermo-Ceram™. LX-7/79-11M. Palmyra, NY. p. 1-6.
37. AMATEX Corp. An Improved Alternative, Norfab® Series 400. Norristown, PA.
1979.
38. Telecon. Maaskant, W., Sales Manager, AMATEX Corp., Norristown, PA.
(215) 277-6100, with T. Henderson, GCA/Technology Division, February 1,
1980. Notebook No. 07, Phone call No. 21.
39. Sil-Temp, a subsidiary of Haveg Industries, Wilmington, DE, comments on
"Background Information on Substitutes for Asbestos," U.S. EPA, July
1980; submitted to H. Pillsbury, U.S. EPA, Washington, D.C. Also,
Sil-Temp Product Literature.
40. Timmons, B., Celanese Corp., Asbestos Roundtable Discussion, EPA/CPSC
Substitutes to Asbestos Conference, Arlington, VA, July 14-16, 1980.
41. Nor-Fab Series 400. Non-asbestos Synthetic Heat-Resistant Textiles.
Brochure. Amatex Corp. 10-79-5M.
42. Telecon. R. Smith, PPG Industries, Pittsburgh, PA, (412) 434-2823,
with N. Krusell, GCA/Technology Division, December 17, 1981. Notebook
No. 1-619-018-012. p. 43.
291
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SECTION 11
MISCELLANEOUS USES
INTRODUCTION
This section combines information on several minor uses of asbestos
fibers, including:
• drilling muds,
• shotgun shell base wads,
• asphalt/asbestos cement,
• foundry sands,
• sprayed-on insulation, and
.• artificial fireplace ashes and artificial snows.
The total fiber consumption for this category was 10,400 metric tons of
asbestos in 1980. For the products noted here, drilling muds consumes the
majority of asbestos, 4900 nut.; a complete breakdown of the remaining 5500 m.t.
was not available. Each section includes a brief introduction to the product.
In general, methodology, contacts, and special qualities are given for each
section. In addition, manufacturers and production volumes are given, along
with substitutes, trends, and conclusions. The section on Drilling Muds contains
extensive information on substitutes and costs. This section had the most data
to offer as asbestos is still used in drilling muds whereas it has been banned
in products such as artificial fireplace ashes, artificial snows, and sprayed-
on in sula t ion.
DRILLING MUDS (FLUIDS)
Asbestos Product
Drilling muds, also called drilling fluids, are used when wells are
drilled by the rotary method. This method involves a drill bit which is
turned by a drill pipe extending down to the bit from the surface of the
ground. The machinery for rotating the pipe is located at the ground surface
(see Figure 3).x The drilling mud is pumped down through the drill pipe and
the drill bit and then returns through the annulus between the drill pipe and
the well bore hole.1 As the fast moving drilling mud passes through the bit
and back up the annulus, it cools and lubricates the bit and picks up the
drilled cuttings, carrying them to the surface. The bottom of the hole is
thus left clean for the drill bit. At the surface, the drilling mud passes
through screening equipment which removes the chips of rocks ground away by
292
-------
Drilling hos«
Drill pipe -*^
Drill collar
Pump
Shale
shaker
Steel
mud
pits
Bit
Figure 3. A circulatory system for a rotary drilling rig.1
293
-------
the drill bit. The mud is replenished with new additives and is recirculated
back through the drill pipe to the drill bit. The process is repeated until
the desired depth is attained.2
Drilling muds typically contain anywhere from 3 to 12 different addi-
tives out of over 150 minerals and chemicals which are appropriate for drill-
ing mud applications. When drilling begins, mud additives are dumped into a
hopper where they are blended with water. The mixture then goes to a tank
near the well and is pumped from this tank through the drilling system.2
Special Qualities—
Asbestos is used in drilling muds to increase the carrying capacity of
the mud (the ability of the mud to bring up cuttings) without significantly
increasing the mud viscosity. This is a useful property since it is easier
to pump a less viscous fluid which results in more power available at the
bit and a faster drilling rate. Additionally, asbestos acts as a loss-
circulation material; that is, a material added to drilling mud to plug all
passages, cracks, and cavities in the drill hole to prevent the loss of the
drilling mud.*
Uses and Applications—
In the field, asbestos is added to the drilling fluids through a mud
hopper or large funnel. Asbestos is used in concentrations normally ranging
from 1 to 2 1/2 kg per barrel [1 barrel = 159 liters (42 gallons)] of mud.1*
However, values as low as 0.2 kg per barrel5 and as high as 9 kg per
barrel have also been reported^ depending upon the desired characteristics of
the drilling mud. Initially, a volume of drilling mud ranging from 150 to 200
barrels is prepared and as drilling progresses, additional quantities are pre-
pared as needed. Under typical conditions, the drilling mud is prepared once
every 8-hour shift. The amount of asbestos added each time is normally less
than 230 kilograms (500 pounds).*
The choice of whether or not to use asbestos in a drilling mud is a
function of the individual well site and depends upon the specific job, soil
characteristics, materials being drilled for, and cost effectiveness.
Product Manufacturing Summary—
Manufacturing process—One manufacturer of asbestos used in drilling
muds (Johns-Manville) processes the asbestos in the following manner. The
asbestos is extruded, highly moisturized (12 to 15 percent) and then pellet- •
ized, thus binding the fibers together. The manufacturer claims that this
process produces an asbestos product with negligible fiber release when it
is used to make drilling muds.7
Name and number of manufacturers—The asbestos product described above
is sold under the trade name of FLOSAL" and marketed by Drilling Specialties
in Bartlesville, OK.5 Approximately 1.6 million kilograms (3.5 million pounds)
per year of FLOSAL" are made and marketed in the United States.8 The other
American manufacturer of an asbestos product for use in drilling muds is
Union Carbide Corporation. This product is marketed by Montello Company of
*Source is an unpublished OSHA document on Asbestos.
294
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Tulsa, OK, under the trade name Super Visbestos® and is advertised as being
sheared, wet-refined, pelletized, chrysotile asbestos.9 Information about
annual production rates was given for Super Visbestos® but, upon further con-
sideration, the Montello Company considered this information to be.proprietary
and it is not listed in this report.10 The Johns-Manville Company mines their
asbestos in Canada and the asbestos used by Union Carbide is mined in Califor-
nia. NL Inudstries, Inc. of Houston, Texas, was also contacted as a potential
(but unconfirmed) manufacturer of drilling muds and their components, but
chose not to divulge any information on the subject.11
Production volumes—Approximately 9,900 metric tons (10,000 tons) of
asbestos fiber were used in 1978 in drilling fluids.12'13 Current production
is estimated to be 4,900 metric tons annually. i'* The shorter grades of
chrysotile fiber are normally used, in either pelletized or loose fiber form.15
Because the two American manufacturers both produce a pelletized form of
asbestos for drilling muds, the loose fiber form is assumed to come from non-
American manufacturers.
Substitute Products
Methodology—
Search Strategy—Information on the use of asbestos in drilling muds and
substitute products was obtained from a literature review and contact with
manufacturers and suppliers of asbestos and substitute products.
Summary of Contacts—Trade Associations, manufacturers of both asbestos
and substitute products, and product distributors were contacted. All are
listed below.
Trade Associations
• Mr. Bob Pigg, Asbestos Information Association, Arlington, VA,
January 1980.
• Mr. Bill Sallens, Petroleum Equipment Supplier's Association,
Houston, TX, January 1980.
• Mr. Steve Chamberlain, American Petroleum Institute, Washington,
DC, February 1980.
Manufacturers
• Dr. Harry Rhodes, Union Carbide Corporation, Niagara Falls, NY,
February 1980.
• Mr. Edmund Fenner, Johns-Manville Corporation, Denver, CO,
January 1980.
• Mr. Don Peteherych, Kelco Division, Merck Company, Houston, TX,
January 1980.
*At this date, the figure is most likely to be still less, given the 1980
downward turn in asbestos consumption for all categories.
295
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Product Distributors
• Mr. Nile Cppeland, Dresser Industries, Magcobar Division,
Houston, TX, January 1980.
• Mr. Phil Theis, Milwhite Company, Inc., Houston, TX,
January 1980.
• Mr. E. E. Clear, Drilling Specialties, Bartlesville, OK,
January 1980.
• Mr. Hal Marple, International Drilling Fluids, Houston, TX,
January 1980.
• Mr. Gregg Jackson, Brinadd Company, Houston, TX, January 1980.
Other
• Dr. George Binder, Exxon Production Research Company,
Houston, TX, January 1980.
Special Qualities—
Asbestos serves a dual function in drilling muds. It increases the
carrying capacity (acting as a viscosifier) and also acts as a loss-
circulation material. No single substitute except perhaps bentonite or
attapulgite clays serve both functions, but a variety of substitutes can be
used as loss-circulation materials. These materials are both added to the
drilling mud to serve the functions that asbestos would perform. Loss-
circulation material substitutes can be used to obtain similar results to
those seen with asbestos fiber. With viscosifiers, each substitute product
may have a specific application and must be chosen according to the require-
ments at the drilling site. Asbestos has a universal application as a vis-
cosifier, whereas substitute viscosifiers must be chosen for the specific
application.
The temperature of circulating drilling mud in oil wells is normally
52°C to 60°C with a maximum temperature at the bottom of the hole of 149°C
and sometimes as high as 204°C. Asbestos can be used at temperatures over
316°C before it breaks down.15 Polymers can generally be used at tempera-
tures of up to 149°C, although new copolymers have been demonstrated at tem-
peratures of from 260°C to over 371°C.5' Bentonite, attapulgite, and other
clays cannot withstand temperatures as high as asbestos, but can normally be
used in most drilling applications up to 177°C to 204°C. Bentonite is the
most widely used viscosifier for freshwater drilling systems, and attapulgite
is the most common viscosifier for saltwater drilling systems.*
Asbestos performance degrades readily from mechanical shear forces.
Xanthan gum polymer can be subjected to high mechanical shear without degra-
dation.6 Clays, such as attapulgite, have the advantage of actually increas-
ing viscosity at higher shear forces.*
*Source is an unpublished OSHA document on Asbestos.
296
-------
Uses and Composition—
There are two types of products that may be substituted for asbestos in
drilling muds—viscosifiers and loss-circulation materials. Each is described
bo. low.
Viscosifiers—Depending upon the characteristics of soil and water into
which a well is being drilled, a number of viscosifying agents can be added
to the drilling mud. These viscosifiers give the drilling mud carrying capac-
ity to bring up the drilled rock pieces. Frequently, a combination of viscos-
ifiers is added to the drilling mud to provide a synergistic effect on the
carrying capacity of the drilling mud or to meet the specific needs at the
site. Each site is different and therefore the types and concentrations of
the viscosifiers are variable. Table 80 provides a listing of substances
which act as viscosifying agents and can be used as substitutes for the vis-
cosifying qualities of asbestos.13'17
TABLE 80.. VISCOSIFIERS USED IN DRILLING MUDS9
Bentonite
Attapulgite clay
Sepiolite clay
Ferrochrome lignosulfate
Synthetic cellulose
Sodium carboxymethyl cellulose
Carboxymethyl hydroxyethyl cellulose
Hydroxyethyl cellulose
Carboxymethyl cellulose
Natural polymers
Xanthan gum biopolymer
Calcium magnesium silicate
Magnesium smectite
Sodium tetraphosphate
Nonionic polymers
Anionic polymers
Guar gum
Mined lignin
Polyacrylamide dispersion
Polysaccharide organics
Sodium acid pyrophosphate
Sodium hexametaphosphate
High temperature stable clay
Nonfermenting starch
Organophilic clay
Pregelatinized potato starch
Pregelatinized corn starch
Polyanionic cellulosic polymer
Gelling agent
Asphaltic gelling agent
Blended polymers
The most commonly used viscosi f.ler is clay, such as bentonite clay or
attapulgite clay.* In addition, the use of polymers as viscosifiers has
gained wide acceptance in recent years. World Oil's 1978-1979 Guide to
Drilling, Workover, and Completion Fluids contains a list of 263 trade names
(including blends) for polymers used in drilling fluids.9 The polymers are
either synthetic or natural. The natural polymers include starch, guar gum,
and Xanthan gum. The synthetic polymers include cellulosics, acrylates,
acrylamides, and maleic anhydride derivatives.18
*Source is an unpublished OSHA document on, Asbestos.
297 ;.-•,
-------
Most polymers sold are used for the same applications in which bentonite
or asbestos is used.5 The Xanthan gum polymer (frequently referred to by its
trade name XC polymer) is the polymer most frequently compared with asbestos
and dtcul n« n y.oocl substitute.5>fi**3'lg
Loss-Circulation Materials—Another function of asbestos in drilling
fluids is to act as a loss-circulation material; i.e., a material to seal
cracks, holes, or extremely permeable streaks in the formation through which
the drilling fluid is lost. When the zones into which the drilling fluid is
lost contain large cracks and holes, the materials added to prevent the loss
of drilling fluid are very coarse grained and normally have high compressive
strength such as coarsely broken walnut shells. When drilling fluid is lost
into formations containing medium-size cracks and holes, medium-grained mate-
rials that are granular, fibrous or flaked, such as walnut shells, bagasse,
and cellophane flakes, are added.1 For formations with fine cracks and tiny
holes, fine grain materials, such as mica flakes or shredded leather, are
added. Since the size of the cracks and holes is not normally known, it is
common practice to add several loss-circulation materials together, to cover
the range of crack or hole sizes.1
There are many low cost substances that can be used as loss-circulation
materials instead of asbestos. The 1979 World Oil Guide to Drilling, Workover,
and Completion Fluids lists over 50 substances that are used as loss-circulation
materials.yA literature source also lists over 50 substances which have been
used as loss-circulation materials and classifies them under the categories of
granular, fibrous, and flaky.1 This list is shown in Table 81.1 Normally,
the cheapest and most readily available loss-circulation material in the
vicinity of the drill site is used.
COST COMPARISON
The number of materials which are used as viscosifiers is too large
to permit a cost comparison of each one. For some of the most common vis-
cosifiers, a cost comparison with the asbestos product is presented in
Table 82."'5,17,20
Table 82 shows that asbestos is generally the cheapest of the common
substances used as viscosifiers in drilling muds. The bentonite and attapul-
gite clays are cheaper per pound but, because more material must be used, the
cost is somewhat higher. The polymers generally cost between $1.00 and $9.00
per pound, but less is used oer barrel than for asbestos, so the cost is more
competitive.
Table 83 shows cost data for some common loss-circulation materials.17
On a cost basis, there are many loss-circulation materials which compare
favorably with asbestos.
298
-------
TABLE 81. LOSS-CIRCULATION MATERIALS1
Granular
Fibrous
Flaky
Beans
Coarse treated bentonite
Crushed rock
Cracked corn cobs
Crushed gilsonite
Ground plastic
Ground nut shells
Ground coke
Ground tires
Peas
Rice
Peach pits
Walnut shells
Polystyrene foam
Asphalt
Cellular plastics
Pecan shells
Almond shells
Ground formica
Cracked wood
Cotton
Bagasse
Flax shive
Wood fiber
Textile fiber
Mineral fiber
Leather
Glass fiber
Peat moss
Tree moss
Feathers
Beet pulp
Hay
Excelsior
Hog hair
Manure
Copper wool
Sponges
Aspen fibers
Cedar fibers
Redwood fibers
Chopped cellophane
Cork
Mica
Ground corn cobs
Vermiculite
Paper, high wet strength
Fish scales
Wheat bran
Gutta-percha flakes
Polystyrene flakes
Linseed hulls
Rice hulls
Cottonseed hulls
299
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TABLE 82. COST COMPARISON OF DRILLING MUD VISCO SIFTERS'*> 5 »17 »20
Material
Asbestos
Bentonite
Attapulgite
Sepiolite
Xanthan (XC)
polymer
Garb oxyme thy 1
cellulose
0.
(0.
0.
(0.
0.
(0.
0.
(0.
7.
(15.
Poly sacchar ides
polymer (DF-VIS)
Hydroxyethyl
cellulose
TABLE 83.
Cost
$/lb
($/kg)
40 -
88 -
08 -
18 -
16 -
35 -
20 -
44 -
00 -
45 -
3.
(7.
5.
(11.
1.
(2.
1.
2.
0.
0.
0.
0.
0.
0.
9.
19
60
95)
00
00)
00
20)
COSTS
00
20)
10
22)
20
44)
25
55)
00
.85)
Amount used
Ib/barrel
(kg /barrel)
(4
(44
(33
(11
(1
0
(0
(2
(17
2
.40
20
.00
15
.00
5
.00
0.5
.10
.25
.55
1
.20
8
.65
- 5
- 11
- 40
- 88
- 20
- 44
- 10
- 22
- 2
- 4.
- 2
- 4.
- 2
- 4.
- 9
- 19
.00)
.00)
.00)
.00)
40)
40)
40)
.85)
Cost
($/barrel) Reference
0
1
2
1
.80
.60
.40
.00
3.50
0
5
8
.90
.00
.00
- 5.00 4,5
-4.00 4
-4.00 4
- 2.50 4
- 18.00 4
- 7.20 5
- 10.00 17
- 9.00 20
OF COMMON LOSS-CIRCULATION MATERIALS17
Material
Asbestos
Cellophane
Mica
Nut shells
Bentonite
Cost
flakes
in
0.45
0.41
0.33
0.32
0.10
$/lb
(1.
(0.
(0.
(0.
(0.
($/kg)
00)
90)
73)
70)
22)
.CURRENT TRENDS
The use of asbestos in drilling muds has decreased from an estimated
9,900 metric tons per year in 1978 to an estimated current annual use of less
than 4,900 metric tons per year.13'11*
The most common polymer substitute for asbestos is Xanthan gum (XC)
polymer. This polymer has no known adverse health effects and has, in fact,
been approved by the Food and Drug Administration as a viscosifier in prod-
ucts for human consumption, such as beer, ketchup, and salad dressing. 5'19
300
-------
The other, common substitute viscosifiers are bentonite and attapulgite clays.
In addition, Lextar of Wilmington, Delaware, reports that it's product-Pulpex-
a polyolefin pulp, is a potential replacement in oil well drilling muds. Its
use is currently being investigated, and at this date, information is considered
proprietary.3
CONCLUSION
Adequate substitutes are available to replace both functions of asbestos
in drilling muds; i.e., to provide carrying capacity (viscosifier) and to act
as a loss-circulation material. A large number of substitutes exist for the
loss-circulation material needs at a competitive cost. The substitute materials
which are viscosifiers are tlie bentonite, attapulgite,and sepiolite clays and
a variety of polymers. The clays are competitive with asbestos in cost. The
polymers are more expensive than asbestos, but less material is necessary to
make up the drilling mud, resulting in a cost-per-barrel figure that is still
more expensive, but nevertheless competitive. The use of asbestos in drill-
ing muds is not mandatory and probably not even necessary in most applica-
tions, as adequate substitutes exist at a competitive cost. As with other
mud additives, the type and amount of asbestos substitute will vary between
drilling sites. Since no typical mud formulation exists, a direct compari-
son between asbestos and nonasbestos drilling muds cannot be made.
SHOTGUN SHELL BASE WADS
Asbestos is used to manufacture base wads for shotgun shells. Both a
literature search and telephone contact were used to gather information for
this section. Most of the data presented here was furnished by Ted McCawley
of Remington Arms Co., Bridgeport, CT.22
Base wads are formed from a mixture of about 36 percent by weight of
asbestos, 54 percent wood flour and 10 percent wax which is pressed to form
the required shape. Only one shotgun shell manufacturing plant (operated
by Remington Arms Co. in Bridgeport, CT) is known to use asbestos. 2 In the
past, approximately 450 metric tons per year of asbestos was consumed in shotgun
shell base wad production. This amount is expected to decrease in the future.
The Remington Arms Co. is currently phasing out the use of asbestos in
shotgun shell base wads. The manufacturer is going to a one-piece polyeth-
ylene shell which is a more stable shell in addition to being less costly.
The Remington Co. reported that they will have converted 95 percent of the
asbestos-containing shotgun shells to one-piece asbestos-free shells by the
end of 1980; i.e., currently). The remaining 5 percent of the asbestos-
containing shells will be converted to asbestos-free shells by the end of
1981.z2
ASPHALT/ASBESTOS CEMENT
This section includes the composition and special properties of asphalt/
asbestos cement as well as a summary of the contacts made during the course
of this report. Appropriate conclusions are noted.
301
-------
Spccial Properties and Product Composition
Asphaltic cement consists of aggregates cemented together with ordinary
paving grades of asphalt such as AC-10 and AC-20.23 The idea behind adding
asbestos to asphaltic cement was to increase the amount of asphalt that could
be put into the mix, which would increase the strength of the material and
increase the life of the pavement.21* While there is some indication that
asbestos might improve the quality of asphalt cement, the prevailing opinion
appears to be that if there is actually anything to be gained by adding asbes-
tos, it isn't enough to make it worthwhile. A spokesman for the National
Asphalt Paving Association said that there was evidence that asbestos might
actually be an agent contributing to cracking.23
The following contacts were made in the course of investigating the use
of asbestos in asphalt cement:
• Mr. Charles Foster, Consultant
National Asphalt Paving Association
6811 Kenilworth Avenue
Riverdale, MD 2080A (301) 779-4880
• Mr. Miguel Leman
Johns-Manville Corporation
Ken-Caryl Ranch
Denver, CO 80217 (303) 979-1000
• Mr. John Tidewell
Federal Highway Administration
Federal Building
Raleigh, NC 27611 (919) 755-4346
• Mr. Durwood Barber
North Carolina Division of Highways
Materials Test Unit
Highway Building
Raleigh, NC 27611 (919) 733-3563
• Mr. Harold Schmitt
Federal Highway Administration
P.O. Box 1915
Sacramento, CA 95809 (916) 440-2428
• Mr. Harold Plate
ASARCO, Inc.
120 Broadway
New York, NY 10005 (212) 732-9500
302
-------
• Mr. James McGee
Arizona Department of Transportation
206 S. 17th Avenue, Room 176A
Phoenix, AZ 85007 (602) 261-7386
• Mr. Tom O'Neil
Maryland State Department of Highways
Highway Maintenance
Baltimore, MD 21201 (301) 383-4108
None of the individuals contacted was aware of any intentional use of
asbestos in asphalt paving in the United States. The only place asbestos is
known to be used in North America is Canada.25
FOUNDRY SANDS
The make-up of foundry sands was investigated as to asbestos content,
use-to-date, and possible substitutes. Also included in this section is
information on insulating sleeves and a complete list of contacts for this
section. Methodology consisted of a literature search as well as a number
of telephone calls to various industry spokespersons.
Principal contacts were:
* Mr. Ezra Kotzin
American Foundry-man's Society
Des Plaines, IL (312) 824-0181
• Mr. Gary Mosher
Industrial Hygienist
Des Plaines, IL (312) 824-0181
• Mr. Phillip Berg
Industrial Hygienist
Asbestos Information Association
Arlington, VA (202) 979-1150
• Mr. S. Kuhn
Johns-Manville Regional Sales Office
Atlanta, GA (404) 449-3300
• Mr. A. Penters
Sales Manager
Whitehead Brothers Co.
Florham Park, NJ (201) 377-9100
• Mr. H. Manvel
Pennsylvania Foundry Supply and Sand Co.
Philadelphia, PA (215) 333-1155
303
-------
Foundry sands are used to make expendable molds for metal castings. The
sand is used with a bonding agent to give the mold the necessary strength
required for castings. The mold is filled with metal through a system of
channels called runners or gates. In addition, there is a system of risers
which ensure that the mold is properly filled and compensates for shrinkage.
Asbestos is actually an undesirable material in foundry sands since it
lowers the refractory point of the sand mold. For this reason, asbestos is
not used in foundry sands for making molds for the production of castings. 6
Personnel from the American Foundryman's Society as well as suppliers of
foundry sands and asbestos stated that asbestos is not used in foundry sands
at this date.27'30
Asbestos has been used in the past as a filler in the formulation for
the manufacturing of insulating sleeves for risers on castings. However,
due to Occupational Safety and Health Administration (OSHA) standards for
airborne asbestos in the workplace, asbestos use for insulating sleeves or
risers has ceased.26'27
Substitute materials for asbestos fibers used in insulating sleeves on
risers for castings include any inert mineral material that can: (a) with-
stand high heat, (b) insulate, and (c) does not crystallize with water at
high temperatures. The materials used to manufacture the insulating sleeves
for risers on castings are proprietary, but include such mineral compounds
as vermiculite, perlite, and diatomaceous earth.26
SPRAYED-ON INSULATION
The use of asbestos in sprayed-on insulation was regulated in 1973 by
the National Emission Standard for Asbestos (40 CFR 61) promulgated by the
U.S. Environmental Protection Agency. This standard limits the amount of
asbestos in spray-on materials used to insulate or fireproof buildings,
structures, pipes, and conduits to less than 1 percent asbestos on a dry
weight basis. This standard effectively eliminated the use of asbestos as
sprayed-on insulation. The 1 percent limitation prevents the use of asbestos
while allowing the use of other materials in which asbestos is a trace con-
taminant. In 1978, the standard was revised to limit the use of sprayed-on
asbestos for decorative purposes to materials containing less than 1 percent
asbestos.
Prior to 1973, it had been common practice to coat pipes, ducts, boilers,
tanks, reactors, turbines, furnaces, and structural members with sprayed-on
asbestos materials.31 The typical form of asbestos used was chrysotile,
although amosite was used in applications such as shaped, block-type gagging
for high temperature pipes. At present, however, the major source of asbestos
fiber emission is during demolition of existing structures and manufacturing
equipment. The National Emission Standard for Asbestos r-equires removal of
asbestos insulation before demolition with adequate wetting of all exposed
asbestos during the removal process.
304
-------
Substitute materials exist for the applications in which sprayed-on
asbestos was formerly used. Both cellulose fibers and rock wool can be
sprayed-on to equipment or structural members to provide insulation.
Cellulose from processed paper (with fire retardant and adhesives added)
is used to make the cellulose material which is sprayed-on for insulation.
The fire retardants are impregnated into the cellulose to give an Underwriter's
Laboratory Class 1 fire rating.32 The sprayed-on cellulose installed cost is
approximately $3.22 to $5.38 per square meter ($0.30 to $0.50 per square foot)
with a 2.54 cm (1 in.) thickness and has an insulating R value of approxi-
mately 1.46 to 1.77 per cm (3.7 to 4.5 per inch). The cellulose material has
been tested for potential health hazards and no health hazards are thought to
exist with the manufacturing or use of the product.32'33
Rock wool (also referred to as mineral wool and slag wool) can be used
in sprayed-on applications for insulation or fireproof ing. 3It The rock wool
is considered to be noncombustible35 and no health hazards associated with
its use have been demonstrated. 3.lt Rock wool has an insulating R value of
approximately 1.50 to 1.57 per cm (3.8 to 4.0 per inch) and installed costs
are between $4.30 and $8.61 per square meter ($0.40 to $0.80 per square foot)
with a 2.54 cm (1 in.) thickness. >35 The mechanical and insulation proper-
ties of rock wool may be inferior to asbestos.
ARTIFICIAL FIREPLACE ASHES AND ARTIFICIAL SNOWS
Artificial Fireplace Ashes
Between 1971 and 1976, over 100,000 logs for gas-burning fireplace sys-
tems were reported sold which were frosted or treated with asbestos-containing
materials.36 At approximately 1/2 pound (0.23 kg) of asbestos per log, approx-
imately 5 tons (4.5 metric tons) of asbestos, mostly chrysotile, were sold annu-
ally for artificial embers.12 In mid-1977, manufacturers stopped producing the
product in anticipation of a subsequent consumer ban by the Consumer Products
Safety Commission. The ban of artificial emberizing materials (ash and embers)
containing respirable free-form asbestos became effective December 15, 1977.
Manufacturers of artificial gas log emberizing material are currently using
four substitutes in their products: vermiculite, rock wool, mica, and syn-
thetic fiber.37
Artificial Snows
Health considerations have nearly halted the use of asbestos in artificial
snows.12
305
-------
REFERENCES
1. Huebotter, E.E. and G.R. Gray (1965), "Drilling Fluids", Kirk-Othmer
Encyclopedia of Chemical Technology 2nd Edition, Vol. 7, pp. 287-307.
2. Zwicker, D.A., Glorious Mud, The Lamp,. Exxon Corporation, New York, NY,
61(4):26-29. Winter 1979.
3. Lextar, A Hercules/Solvay Company, Wilmington, Delaware. Product
Literature - Table 1. Pulpex Polyolefin Pulps - Potential Low Temperature
Asbestos Replacement Applications.
4. Telecon. Peteherych, D. , Kelco Division, Merck Co., Houston, TX,
(713) 621-0110, with Lester Y. Pilcher, GCA/Technology Division,
January 24, 1980, Notebook No. 04, Phone call No. 9.
5. Telecon. Clear, E.E. Drilling Specialties, Bartlesville, OK, (918)
661-5405, with Lester Y. Pilcher, GCA/Technology Division, January 24,
1980, Notebook No. 04, Phone call No. 5.
6. Telecon. Kennedy, B., Messina, Inc., Dallas, TX (713) 225-6383, with
Lester Y. Pilcher, GCA/Technology Division, January 29, 1980, Notebook
No. 04, Phone call No. 11.
7. Telecon. Fenner, E., Johns-Manville Corporation, Denver, CO, (303)
979-1000, with Lester Y. Pilcher, GCA/Technology Division, January 30,
1980, Notebook No. 04, Phone call No. 13.
8. Telecon, Clear, E.E., Drilling Specialties, Bartlesville, OK, (918)
661-5405, with Lester Y. Pilcher, GCA/Technology Division, February 4,
1980. Notebook No. 04, Phone call No. 22.
9. Wright, T.R., Jr., and W. Dudley, Jr., ed. , Guide to Drilling, Workover,
and Completion Fluids. World Oil. p. 116, June 1979.
10. Telecon. Petri, C. , Monetello Co., Tulsa, OK, (918) 665-1170, with
Lester Y. Pilcher, GCA/Technology Division, February 4, 1980, Notebook
No. 04, Phone call No. 20.
11. Telecon and letter, Lahon, C. NL Baroid (and attorney D. May, Jr.) and
L. Pilcher, GCA Corporation, GCA/Technology Division, 2/18/80 and
3/4/80, respectively.
12. Meylan, William M. et. al. , Chemical Market Input/Output Analysis of
Selected Chemical Substances to Assess Sources of Environmental Con-
tamination: Task III. Asbestos. Prepared for OTS, EPA, Washington, D.C.
306
-------
13. American Petroleum Institute, Oil and Gas Well Drilling Fluids, API
Bulletin 13F, Washington, DC, August 1978, page 6.
14. Letter from B.J. Pigg, Asbestos Information Association to Lester Y.
Pilcher, GCA/Technology Division, February 13, 1980. Amount of asbestos
used annually in drilling muds.
15. Telecon. Binder, G., Exxon Production Research Company, Houston, XX,
(713) 965-4810, with Lester Y. Pilcher, GCA/Technology Division,
January 24, 1980, Notebook No. 04, Phone call No. 7.
16. Drilling Fluids: Computer Planning and New High-Temperature Fluid,
World Oil, December, 1979.
17. International Drilling Fluids, Price List, 1979, Middlesex, England,
February 26, 1979.
18. Carico, R.P. and R.R. Bagshown. Kelco Division, Merck and Company, Inc.,
Society of Petroleum Engineers of AIME (SPE) 7747, Description and Use
of Polymers Used in Drilling, Workovers, and Completions, Paper presented
at the 1978 Society of Petroleum Engineers of AIME, Symposium, Hobbs, NM.
October 30-31, 1978.
19. Telecon. Copeland, Nile, Dresser Industries, Magcobar Division, Houston,
TX, (713) 972-2570, with Lester Y. Pilcher, GCA/Technology Division,
January 22, 1980, Notebook No. 04, Phone call No. 03.
20. Telecon, Johnson, G., Brinadd Company, Houston, TX, (713) 644-1895,
with Lester Y. Pilcher, GCA/Technology Division, January 30, 1980,
Notebook No. 04, Phone call No. 14.
2.1. Montello Company, Super Visbestos, Product Bulletin 4/73, Tulsa, OK.
22. Telecon, McCawley, T., Remington Arms Corp., with R. Bell, GCA/Technology
Division, February 15, 1980.
23. Telecon. Foster, C., Consultant, National Asphalt Paving Association,
Riverdale, MD, (301) 779-4880, with S. Duletsky, GCA Corporation,
February 11, 1979, Notebook No. 05, Phone call No. 49.
24. Telecon. Leman, M. Johns-Manville Corporation, Denver, CO, (303)
979-1000, with S. Duletsky, GCA Corporation, February 14, 1980. Notebook
No. 05, Phone call No. 58.
25. Telecon. Plate, H. , Manager of Marketing, ASARCO, Inc., New York, NY,
(212) 732-9500, with S. Duletsky, GCA Corporation, February 20, 1980,
Notebook No. 05, Phone call No. 60.
26. Telecon. Kotzin, Ezra, American Foundryman's Society, Des Plaines, IL,
(312) 824-0181, with Mr. L. T. Pilcher, GCA/Technology Division,
February 15, 1980, Notebook No. 04, Phone call No. 39.
307
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27. Telecon. Mosher, Gary, Industrial Hygienist, American Foundryman's Society,
Des Plaines, IL, (312) 824-0181, with Mr. L. T. Pilcher, GCA/Technology
Division, February 12, 1980, Notebook No. 04, Phone call No. 33.
28. Telecon. Kuhn, S., Johns-Manville Regional Sales Office, Atlanta, GA,
(404) 449-3300, with Mr. L.Y. Pilcher, GCA/Technology Division,
February 15, 1980, Notebook No. 04, Phone call No. 35.
29. Telecon. Penters, A., Sales Manager, Whitehead Brothers Co., Florham Park,
NJ, (201) 337-9100, with Mr. L. Y. Pilcher, GCA/Technology Division,
February 12, 1980, Notebook No. 04, Phone call No. 29.
30. Telecon. Manvel, H., Pennsylvania Foundry Supply and Sand Co., Philadel-
phia, PA, (215) 333-1155, with Mr. L. Y. Pilcher, GCA/Technology Division,
February 15, 1980, Notebook No. 04, Phone call No. 38.
31. Cogley, D. et al. Life Cycle of Asbestos in Commercial and Industrial
Use Including Estimates of Releases to Air, Water, and Land.
GCA-TR-79-73-6, Draft Copy, October 1979.
32. Telecon. Kelly, D., National Cellulose Corporation, Houston, TX,
(713) 443-6701, with Lester Y. Pilcher, GCA/Technology Division,
February 27, 1980, Notebook No. 04, Phone call No. 55.
33. Telecon. Patton T. Habersham Industries, Smyrna, GA, (404) 351-7173,
with Lester Y. Pilcher, GCA/Technology Division, February 25, 1980,
Notebook No. 04, Phone call No. 42.
34. Telecon. Felipe, R. , U.S. Mineral Products, Stanhope, NJ, (201)
347-1200, with Lester Y. Pilcher, GCA/Technology Division, February 25,
1980. Notebook No. 04, Phone call No. 48.
35. United States Gypsum, Thermafiber, Bulletin IV-485, April, 1979,
Chicago, IL.
36. Ray, D.R. Economic Impact of the Ban of Certain Products Containing
Free Asbestos. Consumer Products Safety Commission. Economic Program
Analysis Division. Washington, D.C. November 1977.
37. Part 1305 - Ban of Artificial Emberizing Materials (Ash and Embers)
Containing Respirable Free-Form Asbestos. Federal Register, Chapter
11 - Consumer Product Safety Commission, December 15, 1977.
308
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SECTION 12
DISCUSSION, RESULTS, AND CONCLUSION
DISCUSSION
Results achieved in this analysis of asbestos substitute development and
performance have been determined by the.methodology employed and the avail-
ability of data. The methodology involved:
• gathering a brief description of each asbestos product, including
a definition of special qualities required for each application
and a product manufacturing summary,
• expanding these characteristics to include related nonasbestos
products,
• comparing the cost of the asbestos product to the substitute
options.
• delineating trends and drawing conclusions for substitution
possibilities for each asbestos product category.
To gain the information described above, the following methods of data
gathering were employed:
• collecting and reviewing available data in the form of reports,
brochures, literature searches, etc.,
• contacting manufacturers, users, suppliers, and national trade
associations of both asbestos and nonasbestos products by
phone,
• obtaining current thoughts and opinions as well as product
brochures on the status of substitute development through the
EPA/CPSC Substitutes for Asbestos Conference, Arlington,
Virginia, July 1980,
• reviewing patent information.
In addition, the final report was revised to include comments from asbestos
and substitute product industry sources, such as the Asbestos Information
Association (A.I.A.). Bendix Research Laboratories and Victor Products.
309
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This served both to update the original text as well as to amend and expand
it where necessary. As inquiries were not limited to a single type of source,
this assessment reflects both published technical data and expressions of
user criteria for product selection.
Descriptions of asbestos product uses consisted of defining, as concisely
as possible, the purposes served by each category of products. To a certain
extent this led to the inclusion of market segments not unique to asbestos
products and provided an early indication of possible substitute products.
Availability of data and willingness to discuss the performance of as-
bestos products and substitute products seems to be a function of both a
product stage of development and its marketing. Five classifications may be
noted:
• established products marketed by many manufacturers
• established products marketed by a limited number of distributors
• recently developed products with a captive market
• products under development
• fibers under development
For each of these classifications, the availability of the following types
of data varies: product composition, technical performance specifications,
performance record, and market statistics.
For established products marketed by many manufacturers all data are
readily available. Product manufacturers and distributors do not benefit
by restricting the publication of data. Markets are well characterized and
well known. Included in this classification are: asbestos-cement pipe,
vinyl-asbestos floor tile, and asbestos-cement sheet.
For established products marketed by a limited number of distributors,
marketing data and detailed performance data are not readily available. In-
cluded here are several products in the miscellaneous category.
Recently developed products with captive markets tend to have proprietary
compositions and manufacturing technologies. Properties are known and per-
formance statistics available. Investments in development efforts can be
large. Data on the extent of commercialization are often considered proprie-
tary. This classification includes friction products and, to some extent,
plastics.
For products under development general performance claims tend to be
available and occasionally some composition data are available. Manufacturing
technologies are closely guarded and only limited publishable data are avail-
able. Candidate manufacturers tend to aggressively promote their products
and will furnish data on projected manufacturing capacities.
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For fiber substitutes under development, available data tend to be
speculative.
The final step was the assessment of available data to determine whether
substitutes exist, and whether performance and cost data are available.
Costs were often obtained by telephone contact; they are as up-to-date as
possible but should be used for comparison purposes only.
RESULTS
Substitute availability, performance, and cost data are presented on a
category-by-category basis. Category discussions are subdivided as necessary.
Asbestos Paper Products
Paper products have been grouped into nine subcategories:
• flooring felt
• roofing felt
• beater-add gaskets
• pipeline wrap
• millboard and rollboard
• electrical insulation
• commercial papers
• specialty papers
• beverage and pharmaceutical filters
Asbestos has been used in paper products to add dimensional stability,
moisture, rot, and corrosion resistance, heat resistance, electrical resis-
tance, strength and resilience. In flooring felts, asbestos has virtually
replaced organic and jute felt backings, and is now so well established that
there are no acceptable alternatives at present, although some are under de-
velopment. Nonasbestos beater-add gaskets have made a significant entrance
into the marketplace in just the past year and a half, changing this category
from one in which only limited alternatives existed, to one where the sub-
stitute product promises to become competitive with asbestos in only a short
time. In most of the other paper product categories, suitable alternatives
to asbestos are available. Organic felt, fiberglass felt, and single-
ply membrane systems may replace asbestos roofing felt. In pipeline
wrap applications, saturated fiberglass, extruded epoxys and resins, and
plastic coatings are all viable alternatives, although saturated asbestos
pipe wraps are currently the preferred protection system for oil and gas
311
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pipelines due to their time-tested durability and relatively low cost.
However, the market for pipeline corrosion protective materials is compe-
titive, and the relatively new substitute materials just becoming commer-
cially available may displace asbestos. For millboard and rollboard products,
ceramic boards have been developed which generally equal or better the
asbestos board product, though at significantly higher price. Other replace-
ments in this area are also under development. Substitutes to asbestos in
electrical insulation are also available, but, again, the cost is higher.
In general then, it may be seen that adequate substitutes are available in
many of the paper product categories, though not all, and that they are
specific to certain applications and often are more expensive.
Friction Materials
Friction materials are used in automotive, truck, airplane, railroad,
and industrial brakes and clutches. They require appropriate coefficients
of friction, the ability to withstand high temperatures, dimensional stability,
strength, durability and a lack of abrasion characteristics. Asbestos meets
these requirements, as do a number of materials which may be used as substi-
tutes, although substitute products may not be used in all of the applications
for which asbestos has been developed. Substitutes include glass fiber, steel
wool, mineral wool, carbon fiber, cermets, semimetallic friction materials,
potassium titanate fibers, aramid fibers, vermiculite and silicon nitride.
As friction applications vary, so do the materials most appropriate for each
use. Semimetallic and cermet friction materials may be used in direct asbestos
substitute applications, semimetallic in disc brake pads (it is projected that
in 5 years nearly all original equipment disc brakes in passenger cars and
light trucks will use semimetallic friction materials) and cermets for air-
craft brakes (95 percent of all new commercial aircraft use cermets). Most
railroad and metro systems have now replaced any existing asbestos with an
alternative such as these also. Currently, all drum brake linings contain
asbestos. However, research in this area is ongoing and nonasbestos drum
brake linings may become available at some future date. Research is also under-
way to provide nonasbestos heavy-duty truck and industrial brakes, as well as
vehicle and industrial clutches. To date, asbestos is the best material which
has been found to provide the properties necessary in these latter products.
For certain industrial machinery with a long service life and for which asbestos
friction materials are a required component (often custom fabricated in small
volumes) it is unlikely that substitute products will be developed for machines
currently in service.
Asbestos Cement Pipe
Pipe in use as sewer or waste conduits must be strong, resilient, flexi-
ble, durable, inert and fire-resistant. Asbestos fibers are used to make A/C
pipe products as they impart these characteristics. However, alternatives
are also available in the form of plastic pipe, concrete pipe, vitrified clay
pipe, glass-reinforced concrete pipe, ductile iron pipe and various fiber
substitutes. Each of these alternatives offers different qualities—ductile
iron is more suited for situations involving shock loads, vibration and ground
312
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movement; vitrified clay is cheaper for nonpressure applications; for small
pipe diameters, iron as well as plastic and vitrified clay offer strong compe-
tition, with A/C pipe most suitable for mid-range diameter (6 to 24 inches).
Therefore, for pipe products, economics appears to be the main factor influ-
encing choice; similar properties to asbestos may be obtained from commercially
available alternatives, and many areas of the country specify nonasbestos
piping, simply because of special parameters found in different pipe materials.
Asbestos Cement Sheet
Asbestos imparts high tensile strength, flexibility, resistance to heat,
chemical inertness and a large aspect ratio (ratio of length to diameter) to
this product. It also gives A/C sheet sufficient wet strength so that it may
be molded into complex shapes at the end of the production process. A/C sheet
products thus may include: flat sheet, corrugated sheet, siding shingles, and
roofing shingles. Substitutes for A/C sheet thus vary with the product; in
general it appears that A/C sheet still maintains command of specific markets
where its unique properties make it outstanding (e.g., laboratory table tops
although even in this area, alumina sheet and laminated hardboard may be
adequate replacements), whereas, for more general use, substitute products
are readily available. Both flat and corrugated sheets may be replaced with
glass-reinforced cement sheet, which is superior to A/C sheet in some respects,
such as overall strength characteristics and impact resistance. Cement/wood
board may also be used in place of flat sheet; this product has been available
in Europe for a number of years. Alumina-silica products, galvanized steel,
masonry, and reinforced plastics are also alternatives to the sheet products.
A/C siding shingles may be substituted by hardboard, siding shingles, paneling,
wood shingles, aluminum, stucco, and brick. Roofing shingle replacements in-
clude unreinforced concrete, asphalt and fiberglass shingles. Many of these
products are comparable to or even less expensive than the asbestos product.
Therefore, it appears that A/C sheet may continue to dominate specific appli-
cations, such as lab tables and the overseas construction market, but readily
available, competitive, substitute materials will fill other niches that were
once almost solely those of A/C sheet.
Vinyl Asbestos Floor Tiles
Floor tiles must be tough, dimensionally stable, long lived, economical,
moisture resistant, smooth surfaced, and easy to clean. To date, only asbestos
offers this combination of properties. Although products such as asbestos-free
vinyl tile are available, they not only cost more (as seen with pipe products,
this could be overcome with other unique properties, if it was the only problem)
they also lack durability, resilience, flexibility and wear resistance, which
makes them inappropriate for any heavy duty use applications. Thus, to date,
V/A floor tiles continue to command 91 percent of the resilient floor covering
market.
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Gaskets and Packings
Gaskets and packings are composed of asbestos, an elastomeric binder,
and in the case of some packings, a lubricant. Asbestos has been used not
only because it is heat resistant, resilient and strong, but also because it
is relatively chemically inert which is important for many chemical applica-
tions. However, research on substitute materials has recently brought
products to a forefront which surpass asbestos in these qualities and others.
Replacements on a fiber-for-fiber basis include silica, carbon, Kevlar,
ceramic, and teflon fibers. Material substitutes also exist, in the form of
Gylon, NuBoard, and Victor Products brands for gasket applications. No single
substitute fiber material possesses all of the qualities attributable to
asbestos; however, for any particular application, a substitute fiber can
often be employed to achieve the desired combination of properties. It appears
that many gaskets and packings manufacturers are currently using or switching
to alternative products and buyers are specifying such products. Both health
concerns and a growing awareness of substitute capabilities have caused this
trend. Although asbestos combines versatility and low cost and may be uniquely
suitable to some situations, it does have negative qualities also and a vir-
tually endless list of potential substitutes exists, any one or combination
of which could act to replace asbestos in the gaskets and packings marketplace.
In general, compressed asbestos sheet gasket ing can be replaced with substitute
materials at present, with the added expense to the customer at applications
under 260°C. Graphite, sheet metal and other gasketing materials can replace
asbestos at higher temperatures but often at greater cost. New packing materials
appear to be more than viable alternatives, offering less abrasion and thus
lower operating and maintenance costs. It appears that only sales and engineer-
ing resistance stands in the way of a total switch-over to nonasbestos packings.
Paints, Coatings, and Sealants
Asbestos is used in paints, sealants and coatings because it is strong,
resistent to corrosion and heat, deadens sound, is waterproof, has the required
•viscosity and consistency, is durable and economical. It also has a unique
affinity for asphalt which enables its use in roofing coatings and cements
and automobile undercoatings. As a result of this property, asbestos-free,
asphalt-based coatings which duplicate the characteristics found in asbestos
products have been slow to develop. Although more expensive and sometimes of
inferior quality to asbestos they are now available in countries such as
Sweden where asbestos has been banned, and, to a more limited degree, in
the U.S.
Nonasphalt based coatings made up of several minerals may be used as
substitutes for asbestos. These include talc, barite, diatomite, silica, clay
and mica. More information on performance of such products will become avail-
able as they are further developed and tested. For pipe coatings, asbestos-free
alternatives include enamels, extruded plastics, fusion-bonded thermosetting
powder resins, liquid epoxy and phenolics, various tapes and wax coatings, poly-
urethane foam insulation, and concrete.
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Other products which once contained asbestos, such as texture paints,
spackling and drywall joint compounds are now banned such that asbestos-free
products are coming online as replacements. Other compounds such as the
polyolefin pulp "Pulpex" by Lextar or worker's tools are now used to provide
texture and attapulgite may be an alternative to asbestos in spackle and
dry wall Joint compounds. Fiberglass, fibrous alumina, and magnesium silicate
fiber (containing asbestos) may be used to replace asbestos in automobile and
truck undercoatings, but they are much more expensive and do not display the
properties required of asbestos (affinity for asphalt and viscosity control).
Reinforced Plastics
Asbestos fibers have been used in combination with plastics since the
early 1920's. When added to polymeric materials, asbestos acts to modify
both the physical and chemical characteristics of the composite. Fibers func-
tion both as fillers and reinforcing agents. Asbestos combines the advantages
of both a mineral and fibrous binder carrier with reinforcing action. It also
imparts good surface finish, toughness, resistance to heat and fire, and less
shrinkage and warpage than other fibers. In addition, it improves the ability
to handle the product during processing. There are a wide variety of fillers
and reinforcements available as potential substitutes to asbestos in phenolic
molding compounds. All manufacturers have found suitable substitutes for
certain products and many have been able to completely eliminate the use of
asbestos. Viable substitutes include: fibrous glass, clay, talc, mica, car-
bon fibers, aramid fibers, polyethylene fibers, calcium sulfate, Wollastonite,
and processed mineral fiber from blast furnace slag and silicates. While most
of these materials are already economically and physically competitive with
asbestos, the others probably will become so as the lack of expensive asbestos
dust collecting systems and similar properties at reasonable prices offset the
fiber replacement cost. In general, it appears that there is a well-established
and indeed much progressed trend throughout the reinforced plastics industry
to replace asbestos with alternative materials. Although there may still be
some specialty products which require the use of asbestos, the trend towards
nonasbestos products will continue. In fact, it can be said that, generally,
producers of phenolic molding compounds intend to phase-out the use of asbestos
in most areas, as soon as nonasbestos developments gain customer acceptance.
Only in some specialty applications (including national defense items) will
asbestos then be required.
Textiles
Textiles may be broken down into six different categories: fire-resistant
materials, thermal insulation, electrical insulation, packings and gaskets,
friction materials, and specialty textiles. In each application, asbestos
fibers have been used for strength, processing ability, heat and acid resis-
tance, high tensile strength, resistance to abrasion, and durability. Substi-
tutes for many of the applications include fiberglass, ceramics, organics,
graphite, carbon, quartz, cotton, and special wool blends. Many large manu-
facturers of asbestos textile materials are currently manufacturing substitute
products such as fiberglass and ceramics along with their asbestos products.
315
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Government specifications, such as for fire-resistant materials, are being
revised due to health concerns, which acts to encourage the sale of various
substitute products. The viable substitutes cover a wide range of products,
although they are in most cases more costly than asbestos. Thermal insulation
products using asbestos have been loosing their share of the market to fiber-
glass and ceramic materials; electrical insulation substitutes which are
suitable are readily available; packings and gaskets and friction materials
appear to have adequate alternatives; and specialty textiles using asbestos
have been decreasing, although there still may remain a small number of minor
applications such as lamp and stove wicks for which no satisfactory alterna-
tive appears to exist at present, even though substitute product manufacturers
claim that replacements exist for every asbestos textile product. Overall,
nonasbestos textile products, although higher priced, appear to be readily
available to step into the one time asbestos-dominated market.
Miscellaneous Uses
Miscellaneous uses of asbestos include:
• drilling muds
• shotgun shell base wads
• asphalt/asbestos cement
• foundry sands
• sprayed-on insulation
• artificial fireplace ash and artificial snows
Asbestos has been used in these applications for various reasons—it increases
the carrying capacity of drilling muds without significantly increasing the
mud viscosity, and also acts as a loss-circulation material for the mud; it *
is added to asphalt cement to increase the amount of asphalt that can be put
into the mix, thus increasing the strength of the material and the life of the
pavement (this is no longer thought to be a worthwhile trait); and it acts as
a fire-resistant filler in sprayed-on insulation. Health considerations have
since caused a ban on sprayed-on insulation and artificial fireplace ashes.
Both cellulose fibers and rock wool are now used in place of asbestos in
sprayed-on insulation. Foundry sands no longer use asbestos as it is undesir-
able since it lowers the refractory point of the sand mold; it also appears to
be undesirable in asphalt/asbestos cement as it may contribute to cracking. In
shotgun shell base wads, asbestos use is currently being phased out. The sole
manufacturer is quickly shifting to a one piece polyethylene shell which is
more stable in addition to being less costly. As for drilling muds, asbestos
use is decreasing due to health concerns. Adequate, cost competititve substi-
tutes are available to replace both functions of asbestos in drilling muds—
the carrying capacity and as a loss-circulation material. In general, the
miscellaneous uses of asbestos are small, and nonasbestos products are being
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developed to fill in voids where asbestos has been phased out. In some cases,
the asbestos product simply does not warrant production in the marketplace any
longer, and thus is not replaced at all.
CONCLUSION
In certain product categories, data were limited. In part this reflects
the difficulty inherent in obtaining accurate and complete information on a
large and complex sector of the economy. Production volume data for many
asbestos and substitute products could not be obtained except as gross composite
estimates. Technical details concerning exact composition or manufacturing
methods were closely guarded in some cases. Nevertheless, it has been possible
to determine whether acceptable products are available in the marketplace.
With the exception of a few specific applications, each asbestos product
category has commercially available alternatives. These alternatives are
listed in Table 84. Required characteristics of the asbestos product sub-
stitutes, including availability, performance characteristics, cost, and
additional comments, are summarized in Table 85. Resilient floor coverings
constitute a major asbestos product category for which an economically viable
direct substitute product is not available. For any particular application,
the variety of available substitutes is a function of many factors including:
• customer preference
• product performance
• economics
• labor union demands
• regulatory controls
• construction trends (e.g., sewer construction)
In light of these complexities and changes over time it will be advisable to
consider such factors when applying the data of Tables 84 and 85. In other
words, these tables represent present conditions in a rapidly changing market.
Definition of the properties required in each application has frequently
shown that asbestos products are "overqualified" for many applications. That
is, not all of the properties imparted by asbestos are required for all appli-
cations. Often, a single asbestos product is employed for a range of applica-
tions differing in severity. The result is that inexpensive substitutes may
be available for mild service conditions, whereas more expensive substitutes
are required for severe service applications.
In no case is there a fiber or material alternative that can completely
replace the special qualities of asbestos in every use; instead, a wide range
of alternatives are offered, each fitting only a small niche in the range of
317
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TABLE 84. POTENTIAL SUBSTITUTE PRODUCTS*
l IIH |irtiiliicl. rut i-y.nry
1'olcill. lul
tluturi
I . I'Al'KR PRODUCTS
a. Flooring felt
b. Roofing felt
c. Beater-add gaskets
d. Pipeline wrap
e. Millboard
f. Electrical insulation
g. Commercial papers
h. Specialty papers
i. Beverage filters
' • "Backless" sheet vinyl
• Foam-cushioned backings
• "Place and press" vinyl tile squares
• Carpet, wood, etc.
• Organic felt
• Fiberglass felt
• Single-ply membrane system
• Ceramic paper
• Teflon
• All-metal
• Silicone rubber
• Saturated fiberglass
• Coating materials-enamels, wax, etc.
• Fiberglass
% Mineral" wool
• Ceramic boards
• Aramid paper
• Cellulose
• Fiberglass
• Ceramics
• Cellulose
• Fiberglass
• Plastics
• Cellulose
• Aluminum
• Steel
• Ceramics
• Fiberglass
• Cellulose
• Glass
2. FRICTION PRODUCTS
a. Automobile brakes
b. Heavy-duty truck brakes
c. Railcar brakes
d. Aircraft brakes
e. Industrial brakes
f. Vehicle clutches
g. Industrial clutches
Semimetallics
Hybrids
Semimetallics
Cermets
Carbon composite
Rubber polymer
Cermets
Carbon composite
(continued)
318
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TABLE 84 (continued)
Potential substitutes
Asbestos product category
•). A/C PIPE
« Cast and ductile iron
a Steel
o Reinforced and nonreinforced concrete
« Plastic - (PVC)
e Vitrified clay
« Glass (GRC) and carbon fibers
4. A/C SHEET
e Cement/wood board
e Glass - GRC
6 Plastic - reinforced concrete sheet
0 Polypropylene layered cement sheet
o Aluminum sheet
« Masonry, galvanized steel, wood
5. FLOOR TILES
c Cellulose fibers
e Synthetic polyolefin pulp
o Solid vinyl tile; vinyl blends
» Rubber tile
« Wood, carpet
6. GASKETS AND PACKINGS
o Silica, ceramic, graphite, aramid, teflon fibers
o Inorganic and inert fibers, bonded
t> Fluorocarbon particles
o Precursors to carbon fibers and rayon
7. SEALANTS
a. Asphalt-based
b. Nonusphalt-based
a Volatiles and ash
t) Cellulose
» Fiberglass, polypropylene, polyesters, acrylics, cotton
e' Talc, barite, diatomite, silica, clay, mica
8. REINFORCED PLASTICS
s Fibrous glass, carbon fiber, aramid fiber, Wollastonice,
processed mineral fiber, and polyethylene fiber
a Clay
e Talc
e Mica
o Calcium sulfate
9. TEXTILES
e Glass
e Ceramics
e Organics
B Carbon
o Quartz
* Cotton
(continued)
319
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TABLE 84 (continued)
AM|U-IIIOH product i:ni»'H
-------
TABLE 85. SUBSTITUTE PRODUCT CHARACTERISTICS
Asbestos product, category
1. PAPER PRODUCTS
a. Flooring felt
b. Kiiol'lnx felt
c. Beater-add gaskets
d. Pipeline wrap
e. Millboard
f. Electrical insulation
g. Commercial papers
h. Specialty papers
1. Beverage filters
2. FRICTION PRODUCTS
a. Automobile brakes
b. Heavy-duty truck brakes
c. Railcar brakes
d. Aircraft brakes
e. Industrial brakes
f. Vehicle clutches
g. Industrial clutches
Availability
Under
development
Cummer c lolly
available
Commercially
available
Commercially
available
Commercially
availabile
Commercially
available
Commercially
available
Commercially
available
Commercially
available
Commercially
available
Commercially
available
Commercially
available
Commercially
available
Under
development
Under
development
Under
development
Performance characteristics
—
Meets all requirements
Meets many requirements
May be less durable
Meets many requirements
Meets all requirements
Meets some requirements
Meets all requirements
Meets most requirements
Meets all requirements
—
—
Meets all requirements
—
—
—
Costs
—
Comparable
Higher
Higher
Higher
Higher
Much higher
Comparable
Higher
Comparable
—
—
Higher
—
—
—
Comments
Material substitutes such as
carpet readily available.
fiber felt substitute still
under development
Some substitutes pre-date
asbestos; best covering
varies with roof.
Substitute development quickly
underway.
Asbestos pipeline wrap
presently preferrred.
Substitutes not available
for all applications.
Extensive substitute products
available.
Substitutes not available
for all applications.
Durability may not equal
asbestos.
For haze removal, asbestos
still superior.
Proprietary composition
—
—
All new brakes cermet; some
asbestos still in use.
Many diversive uses.
—
—
3. A/C PIPE
A. A/C SHEET
5. FLOOR TILES
6. GASKETS AND PACKINGS
7. SEALANTS
a. Asphalt-based
b. Nonasphalt based(
8. REINFORCED PLASTICS
9. TEXTILES
10. MISCELLANEOUS
Commercially Meets all requirements
available
Commercially Meets most requirements
available
Commercially Less durable
aval lable
Commercially Met'ts most requirements
available
Comparable Several available substitutes.
Some higher Substitutes for high temperature
applications more costly.
Higher Currently, no substitutes
comparable to asbestos.
Variable Equipment redesign required in
certain cases.
Expected to be less durable Comparable Specially treated cellulose
Under
development
Commercially Meets some requirements
avallable
Commercially Mejts most requirements
Commercially Meets most requirements
available
Commercially Meets most requirements
available
fibers.
Generally Asbestos banned in some
higher products.
Variable Many manufacturers have already
switched to substitutes.
Higher Substitutes available for most
applications.
Some higher Some asbestos products banned;
drilling mud substitutes may
be much more 3xpensive.
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applications for which asbestos has come to be counted on. Although costs
of substitute products are generally higher, other considerations may act to
increase the asbestos product cost, while at the same time increased production
of Bubatilute products may drive their costs down, effectively negating the
current cost gaps by bringing nonasbestos products and their individual
properties into wide acceptance and use.
It seems likely that, at least in the near term, there will be a core
of products requiring asbestos. This includes products which cannot function
without asbestos-containing components unless they are redesigned. Thus,
substitutes for these products are not available for the replacement parts
market but they might be available for the original equipment market. Also
included in this core are products for which no technically and economically
acceptable substitutes have been found for all applications; e.g., vinyl
asbestos floor coverings.
Products such as specialty papers, roofing felts, A/C pipe, and aircraft
brakes are, to some extent, being displaced by products which have been avail-
able for several, and sometimes many, years. Many of the available substitute
products fulfill some but not all of the requirements placed on asbestos
fibers. Asbestos still provides the most complete haze removal of any beverage
filter; it is presently the preferred pipeline wrap due to the length of time
it has been on the market; it is the single best component of tough vinyl
floor tile; it is sometimes unique in high-temperature A/C sheet applications;
and it is a low cost viscosifier in drilling muds.
Nonasphalt-based sealants, many A/C sheet products, gaskets and packings,
reinforced plastics, and textiles fall somewhere in-between - substitutes are
available, but often the cost is higher, the product lacks the durability
attributed to asbestos, or certain applications may not be filled by the non-
asbestos product. Products still in the development stage include flooring
felts, various types of brakes and clutches, and asphalt-based sealants.
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