ANALYSIS OF FIBER RELEASE FROM
CERTAIN ASBESTOS PRODUCTS
Draft Final Report
Task 1
r_-.
.:_\
GCA CORPORATION
Technology Division
213 Burlington Road
Pedloro Mass 01730
-------
GCA-TR-82-16-G
Prepared for
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Toxic Substances
Chemical Control Division
Washington, O.C.
Submitted in Partial Fulfillment of
Contract No. 68-01-5960
Technical Directive No. 15
EPA Project Officer
James Buiman
ANALYSIS OF FIBER RELEASE FROM
CERTAIN ASBESTOS PRODUCTS
Draft Final Report
Task 1
February 1982
Prepared by
Peter H. Anderson
William J. Farino
GCA CORPORATION
GCA/TECHNOLOGY DIVISION
Bedford, Massachusetts
-------
CONTENTS
Tables v
1. Introduction 1
Report Organization 2
Analytical Results 2
References 6
2. Asbestos-Cement Pipe 7
Introduction 7
Product Manufacturing and Composition . • 7
Secondary and Consumer Use 9
Environmental Release 9
References 18
3. Asbestos Paper 20
Introduction 20
Flooring Felts 21
Roofing Felts 23
Beater-Add Gasket 26
Pipeline Wrap 28
Millboard 29
Specialty Paper Products 33
Commercial Paper 38
Electrical Insulation 43
References 47
4. Friction Material 49
Introduction 49
Brake Linings 49
Clutch Facings 57
References 60
5. Flooring Products 62
Introduction b2
Vinyl-Asbestos Floor Tiles 62
Asphalt-Asbestos Floor Tiles 64
References t 66
6. Caskets and Packing 68
Introduction 68
Gaskets 68
Packing 73
References < 75
/. Coatings and Sealants 77
Introduction 77
Asphalt/Tar-Based Sealants 77
111
-------
CONTENTS (continued)
Water Soluble Latex or Uypaum-Basud Sealants 79
References 85
8. Asbestos-Cement Sheet 87
Introduction 87
Product Manufacturing and Composition 87
Secondary and Consumer Use 88
Environmental Release 88
References 92
9. Textiles 94
Introduction 94
Textile Manufacturing and Composition 94
Secondary and Consumer Use 96
Environmental Release 98
References 102
10. Asbestos-Reinforced Plastics 104
Introduction 104
Product Manufacturing and Composition 104
Secondary and Consumer Use 105
Environmental Release 106
References 107
11. Conclusion and Recommendations 108
Summary of Findings 108
Product Testing Recommendations 130
References 133
-------
TABLES
Num'>er Page
i Major Asbestos-Containing Products within Each Product
Category 3
'. Results of Personal Monitoring of Employees Performing A/C
Pipe Operations ...• 12
3 Results of Laboratory A/C Sewer Pipe Product Testing Performed
by GCA 15
'+ Asbestos Fiber Concentrations Associated with the Installation
and Removal of Vinyl Sheet Flooring Backed with Asbestos
Flooring Felt 24
5 Asbestos Fiber Concentrations Associated with Simulated
Pipeline Wrap Removal Activities ....'. 29
iS Industrial, Commercial, and Residential U;e of Asbestos
Millboard and Individual Applications 32
7 Asbestos Contamination in Filtered Wines 36
8 Asbestos Fiber Release from Simulated Asbestos Paper 'landling
Activities 42
9 Airborne Asbestos Concentrations Resulting from Asbestos
Electrical Insulating Paper and Board Manufacture and
Installation 45
10 Value of Asbestos Friction Material Shipments 50
11 Property Modifiers in Friction Materials 51
12 Summary of Published Data - Asbestos Emissions from Brake
Lining Use 54
13 Asbestos Fiber Concentrations Recorded During Automobile and
Truck Brake Servicing 56
-------
TABLES (continued)
Number Page
14 Asbestos Fiber Concentrations Associated with Eight Types of
Brake Drum Cleaning Methods ................. 57
15 Asbestos Exposure Levels in Rebuilding Brake and Clutch
Assemblies .............. ............ 58
16 Asbestos Fiber Release from Vinyl-Asbestos Floor Tile
Installation, Use, Maintenance, and Removal ......... 65
17 Asbestos Fiber Concentrations- Associated with Various
Compressed Asbestos Sheet Casket Handling Activities ..... 70
18 Asbestos Fiber Concentrations Associated with Spray Application
of Asbestos-Containing Petroleum-Based Coating Products ... 80
19 Summary of Airborne Asbestos Fiber Concentrations Encountered
in the Drywall Taping Process ................ 83
20 Fiber Release Concentrations Associated with Asbestos-Cement
Sheet Product Use Activities ................. 89
21 Air Monitoring Test Results Using a Circular Saw and Drill on
Flat A/C Sheet ........................ 91
22 Exposure to Airborne Asbestos Fibers During A/C Sheet
Manufacturing ........................ 91
23 Forms of Asbestos Textiles Used in Asbestos Products ...... 95
24 Airborne Asbestos Fibers Resulting from the Use of Asbestos-
Containing Gloves ...................... 100
25 Exposure to Airborne Asbestos Fibers During Primary and
Secondary Textile Manufac luring ............... 10 1
26 Asbestos Fiber Concentrations Associated with Reinforced
Plastic Secondary Finishing Operations ............ 106
27 Measured Asbestos Fiber Concentrations Resulting from Secondary
and End Use Product Testing Activities ............ 10')
26 Numerical Summary of Monitoring Studies Performed on Asbescos-
Containing Products ..................... 131
VI
-------
SECTION 1
INTRODUCTION
Over recent years, much has been written about worker exposure to
asbestos fibers during the manufacture and subsequent fabrication of
asbestos-containing products. Governmental regulatory agencies such as the
Occupational Safety and Health Administration (OSHA), Consumer Product Safety
Commission (CFSC), and United States Environmental Protection Agency (EPA)
have been entrusted with the responsibility of protecting workers, consumers
and the environment from exposure to asbestos fibers. Under the Toxic
Substances Control Act (TSCA),1 EPA's Office of Toxic Substances is
responsible for controlling human exposure to asbestos that may present an
unreasonable health risk. Within the confines of TSCA, this study was
undertaken to profile the activities routinely performed on
asbestos-containing products in secondary finishing operations, installations,
repair, or day-to-day handling and to report the levels of asbestos fibers
encountered during such activities.
It is estimated that asbestos fibers have been used to produce 2,000 to
3,000 discrete commercial and industrial products.2 Asbestos fibers may be
released during product manufacturing, distribution in commerce, and end use.
Persons may be exposed to asbestos fibers during the performance of these
activities. Because OSHA studies provide a relatively adequate data base for
fiber release during primary manufacturing and fabricating, this study has
focused on identifying asbestos fiber release from secondary and consumer
product use activities.
The information presented in this report was compiled from an extensive
survey of publicly available data and telephone interviews with manufacturers,
fabricators, distributors, and end users of asbestos-containing products. A
computerized literature search of eleven data bases revealed that the amount
and diversity of asbestos fiber release data publicly available is limited.
Various product testing laboratories have monitored fiber release from
experiments simulating actual product use activities, but due to the
preliminary nature of their findings or to proprietary agreements they are not
willing to disclose publicly the results of their studies.
The purpose of this study is to report measured or expected airborne
asbestos fiber concentrations resulting from secondary and consumer product
use activities. The data presented are intended to provide EPA officials with
the information they need to assess whether exposure to asbestos throughout
its life cycle presents an unreasonable risk to human health. Where the
-------
presence of risk is determined, EPA will consider developing regulations,
under TSCA authority, to eliminate the human exposure. Once it has been
determined that the substance in question presents an unreasonable health
risk, the Agency under Section 6(a) of TSCA, can restrict chemical processing,
limit quantities that can be used, require appropriate labels, and/or mandate
recordkeeping.
REPORT ORGANIZATION
This report is organized by the asbestos product categories presented in
Table 1. The chapters are arranged sequentially by category based on
descending rate of annual asbestos consumption. Due to the versatility of
some products and the intermediate uses of others, there will be some overlap
of products between categories. The overlap will be noted but not repeated
Product profiles include a brief description of product manufacturing
and/or fabricating operations, a discussion of secondary and consumer product
uses and a presentation of monitoring data or potential fiber release
estimates when they exist. Secondary and consumer product use activities
include product finishing, installation, repair, and day-to-day handling.
ANALYTICAL RESULTS
Asbestos fiber concentrations presented are based on the results of three
different analytical techniques. The three microscopic analysis techniques
are phase contrast, polarized light microscopy (PLM) and scanning electron
microscopy (SEM). Phase contrast and PLM are optical light microscope
analytical procedures.
Phase contrast analysis is the recommended method of the National
Institute for Occupational Safety and Health (NIOSH) for counting asbestos
fibers.^ Fibers counted are those that are 5 microns (um) long or longer
and have a length to width aspect ratio of 3 or greater. The major
disadvantage of phase contrast analysis is that the technique cannot be used
to differentiate asbestos fibers from nonasbestos fibers.
Polarized light microscopy analysis is used to count fibers of the same
dimensions as the phase contrast method. However, PLM analysis allows the
operator to distinguish asbestos fibers from nonasbestos fibers. The
technique takes advantage of the specific optical properties each asbestiform
mineral exhibits, thus allowing qualitative identification. Scanning electron
microscopy analysis is the most powerful analytical tool of the three,
providing the operator high levels of magnification. Compared with either of
the two optical techniques, fiber counts by SEM analysis can exceed 50 times
the number counted by phase contrast or PLM. Used in conjunction with energy
dispersive X-ray analysis, which is almost always the case, SEM analysis
provides qualitative results. Because of its powerful magnification
capabilities, SEM analysis is also used to determine particle size
distribution of material sampled.
-------
TABLE 1. MAJOR ASBESTOS-CONTAINING PRODUCTS WITHIN
EACH PRODUCT CATEGORY
I. Asbestos-Cement: Pipe - (40.2)a
• Water Transmission Pipe (pressurized)
• Sewer Transmission Pipe (nonpressurized)
• Other - Electrical conduits, chemical process pipe
II. Asbestos Paper Products - (25.1)
• Flooring Felt
• Roofing Felt
• Beater-Add Gaskets
• Pipeline Wrap
• Millboard
• Specialty Papers
• Commercial Papers
• Electrical Insulation
III. Friction Material - (12.2)
• Brake Materials (linings and disc pads)
• Clutch Facings
• Other
- Discs for automatic transmissions (paper product)
- Woven clutch facings (textiles)
IV. Flooring Products - (10.1)
• Vinyl-Asbestos Floor Tile
• Asphalt-Asbestos Floor Tile
(continued)
-------
TABLE 1 (continued)
V. Gaskets and Packing - (3.4)
• Compressed Sheet Gaskets
• Impregnated Millboard )
'. Packing
• Yarn (textile) }
VI. Coatings and Sealants - (3.0)
• Petroleum-based products
• Water soluble Latex or Gypsum-Based products
VII. Asbestos-Cement Sheet - (2.2)
• Roofing Shingles
• Siding Shingles
• Flat Sheet
• Corrugated Sheet
VIII. Textiles - (0.5)
• Industrial Packings
• Electrical Insulation
• Thermal Insulation
• Textiles (fire retardant clothing, belt conveyors, and curtains)
IX. Asbestos Reinforced Plastics - (0.4)
• Electronic Industries (commutators)
• Automotive Industries
• Printing Industries
Percentage of 1980 annual asbestos consumption.-*
-------
Discretion should be employed when interpreting and comparing the fiber
concentration data presented in this report. Care should be taken not to
compare optical microscopy results directly with SEM analyses. Similarly, the
quantitative results of phase contrast analysis should be fully understood
before comparing them to quantitative and qualitative results obtained from
PLM analysis. A concerted effort has been made to identify these analytical
characteristics which are important to remember when interpreting the data.
In addition, one should not mistakenly compare peak concentrations
occurring during Che performance of an activicy with time weighted average
concentrations that have been scaled over an eight hour period. Finally, some
of the data reported may be out of date. Implementation of new control
measures and changes in product formulations should result in fiber release
levels lower than some of those presented. In all cases, the most recent
fiber concentration data are reported.
-------
REFERENCES
1. Toxic Substances Control Act, 15 USC 2601. Promulgated October 11,
1976. Public Law 94-469, 94th Congress.
2. Federal Register, October 17, 1979, Commercial and Industrial Use of
Asbestos Fibers; Advance Notice of Proposed Rulemaking. Vol. 44, No. 202.
3. Clifton, R. A., Asbestos. 1980 Minerals Yearbook, U.S. Bureau of Mines,
Washington, D.C.
4. National Institute for Occupational Safety and Health: Asbestos Fibers
in Air - Analytical Method. (March 1976). pp. 239-1 to 239-20,
unpublished.
-------
SECTION 2
ASBESTOS-CEMENT PIPE
INTRODUCTION
Asbestos-cement (A/C) pipe is manufactured in sizes ranging from 10 to 81
centimeters (ca. 4 to 32 inches) in diameter.'- The product is used
primarily for water distribution and sewage transport. Approximately 70 to 75
percent of all the A/C pipe produced is used for water supply systems, 20 to
25 percent is used for sewer pipes. ' The remaining pipe produced is installed
as telephone and electric wire conduit, with a minor fraction for air
ducting.1 In 1978, 321,800 kilometers (ca. 200,000 miles) of A/C pipe was
estimated to be used to distribute .water to U.S. consumers.2
Proportionally, most of this pipe is located West of the Mississippi River.1.
Release of airborne asbestos fibers from A/C pipe is minimized after
manufacture and finishing. Candidates for exposure would be contractors who
install, maintain, and repair or modify water (pressure) supply or sewer
(nonpressure) systems. During these operations, cutting may be required which
could release fiberous emissions. Asbestos fibers contained within A/C pip<;
are bound in a cement mortar matrix.^ In addition, A/C pipes are often
coated with a layer of CaC03 or other detourant to erosion of fibers from
the surface.^ The pipes are also laminar in structure slowing any
corrosion/erosion processes as well as enabling cutting for branch pipes with
little risk of cracking beyond the cut area.^
Once permanently installed, the greatest potential for environmental
fiber release is "to the water or sewer system. Fluids passing through the
pipes have the potential to pick up fibers through erosion and leaching.
Several studies have been conducted to determine the asbestos content of water
supplied to the consumers.^~° Although the overall consensus is that much
of the asbestos is derived from natural sources such as serpentine rock
formations, most studies do not distinguish between the sources of asbestos
fibers found in the water. Studies concerned strictly with fiber release from
A/C pipe, however, all show a slight increase of asbestos fiber counts in
water which has passed through such pipe. 3»*-H
PRODUCT MANUFACTURING AND COMPOSITION
The manufacture of asbestos cement pipe is governed by specifications jet
by the American Water Works Association (AWWA)." Pipe is classified
-------
according to Che designed internal pressure, ranging from 2070 to 6206
kilopascals (ca. 300 to 900 psi), and according to chemical composition. Type
I A/C pipe has no limit upon the amount of uncombined calcium hydroixde
permitted in the product, and Type II A/C pipe must not contain greater than
one percent uncombined calcium hydroxide. Type I pipe is generally cured
under ambient conditions. The mixture is 15 to 25 percent asbestos and 75 to
85 percent portland cement. Type II pipe (autoclave cured) is made of 15 to
25 percent asbestos, 42 to 53 percent cement, 34 to 40 percent silica and up
to 6 >ercent finely ground solids from crushed or damaged pipe as filler.1
Chrys)tile asbestos is most commonly used in A/C pipe production. A
relatively small amount of crocidolite and an even smaller amount of amosite
is also used.^
Manufacturing begins when raw asbestos, generally packaged in 50 kg (ca.
100 Ib) bags, is delivered to the plant by railcar or truck, and stored until
needed for mixing. The raw asbestos is weighed and charged with the cement
and other ingredients into a dry mixer, which acts to fluff the fibers and
prepare a homogeneous mixture. The dry mix is then conveyed to a wet mixer or
beater where water is added to make an A/C slurry of approximately 37 percent
water.^ The slurry flows or is pumped to the pipe-forming machine vats
where it is deposited on one or more rotating horizontal, cylindrical
screens. Excess water is removed from the slurry layer on the screen. The
resulting layer of asbestos-cement material, 0.05 to 0.25 cm (ca. 0.02 to 0.10
in.) thick, is transferred to an endless-felt conveyor belt that travels over
vacuum boxes to remove the water.^ The wet mat is then transferred to a
mandrel or accumulator roll which winds the mat into pipe stock of the desired
thickness. Pressure rollers bond the mat to the layer previously deposited
and further remove excess water. The pipe, usually cast in 3.0 to 4.6 meter
(ca. 10 to 15 foot) lengths, is then removed from the mandrel, air cured, and
final cured in an autoclave using saturated steam. Cured pipe sections are
transported to finishing operations where the pipe is cut to uniform lengths
and machined in a variety of ways (sawing, lathing, drilling) and outfitted
with a coupling. To ensure a tightly fitted pipe joint, the ends of the pipe
sections are machined smooth on a lathe. The finished pipe is inspected, and
each section of "pressure pipe" (pipe used for conveying wa:er under pressure)
is tested hydrostatically."
In addition to full and partial lengths, manufacturing plants also
produce a variety of standard and special fittings. Pipe couplings are the
most widely used fittings. To mate with a machined pipe, inside surfaces of
the coupling must be grooved to hold a rubber seal. Other fittings (tees,
elbows, reducers, etc) are produced on a less frequent schedule." Most
manufacturing plants also produce specialty fittings and pieces on an
individual basis. Pipe fittings production include sawing, drilling,
machining, boring, and bonding. Some specialty applications require pipe
lengths to be machined over their entire length with a lathe." As a final
step, the pipe may be lined with a coating to further increase its corrosion .
resistance and improve flow characteristics. Vinyl is a commonly used
liner.16
-------
Reliable production volumes of A/C pipe cannot be accurately estimated
because such information is considered proprietary by manufacturers. The
total quantity of asbestos consumed for the production of A/C pipe can be
used, however, as a market indicator. In 1980, 144,000 metric tons or 40
percent of the total annual domestic asbestos consumption was for A/C pipe
production.*7 Projected trends for A/C pipe consumption vary from modest
growth (5 to 7 percent over the next 3 to 7 years), through market
stability, !•* to actual decline.17 Between 1978 and 1980 asbestos
consumption for A/C pipe dropped. Polyvinyl chloride (PVC) pipe inroads on
the water pipe market are predicted to be primarily at the expense of ductile
iron pipe rather than A/C pipe. However, in the case of sewer pipes,
especially in the southern U.S. where higher temperatures and low flow rates
accelerate acidic deterioration of A/C pipe, PVC pipe may claim a substantial
share of the market, perhaps eventually displacing A/C pipe if the letter's
cost cannot be lowered.15
SECONDARY AND CONSUMER USE
A/C pipe has a relatively narro.w range of application compared to other
asbestos-containing products. As indicated above, nearly 100 percent of the
A/C pipe produced is used for water or sewage transport. The remaining pipe
is used for conduits for electrical or telephone wire or air ducts.*
It is noted that A/C pipe is not really a consumer product. Finished
pipe is distributed primarily to municipal water works construction personnel
and contractors. Installation is almost always performed by professional
workers, who are familiar with recommended installation procedures.
Because of its relatively recent introduction (about SO years ago) and
very long service life, there is little information available on the repair
and/or replacement of A/C pipe used for water transport systems. Except under
very aggressive water conditions, once in the ground, A/C pipe lasts forever.
Engineering standards recommend that urban lines be replaced every 75
years.1^ However, this is often not the case due primarily to the lack of
monies and the inconvenience of digging up streets. The water line
replacement cycle in New York City is 300 years and in Jersey City 500
years.18 In highly populated urban areas, A/C pipe when replaced, might be
removed, crushed, and trucked to a landfill. In lower density areas, the old
pipe might be left in the ground and new pipe laid down beside it. In the
former case, minimal asbestos fiber release from the old pipe is expected and
in the latter instance, none.
ENVIRONMENTAL RELEASE
One of the major advantages of A/C pipe use is the ease of installation.
Relatively little onsite sawing, cutting, drilling, or machining of A/C pipe
is required during installment. Although there may be transitory worker
exposure, the likelihood of significant asbestos fiber release into the
environment is minimized since the fibers are immobilized in the cement
matrix. Piping is placed in ground and fitted with rubber gaskets which act
as a cushion ag*. Abrasion as well as providing a more flexible decay
-------
resistant seal.1 Once layed in ground Che pipe is completely buried with
the only mechanism available for fiber release being through the water which
it carries. As a result of these activities, the general public's exposure to
airborne asbestos fibers from installing A/C pipe is minimal.
Should field finishing be required, it would be a potential source of
airborne asbestos fibers. Cutting or lathing pipe has the potential to
release airborne asbestos fibers, although this can be minimized with the
proper use of specifically designed tools and cleanup equipment. Special saws
and lathing tools as well as drills have been developed that are equipped with
dust control devices.15,19 Control devices include local vacuum systems
with filters, wet cutting tools and lathes or tools with self-contained vacuum
and filter fittings.
A recent study sponsored by the Association of Asbestos Cement Pipe
Producers (AACPP),'-^ was conducted to measure worker exposure during the
following A/C pipe field operations:
1. Unloading
2. Laying pipe in the trench
3. Cutting operations on both pressure and sewer pipe
a. Cutting with hack saw
b. Cutting with snap cutting equipment
c. Cutting with abrasive disc, wet
d. Cutting with abrasive disc, dry
e. Cutting with hammer, chisel and rasp
>\. Machining operations
a. Machining with a manual field lathe
b. Machining with a power-driven lathe
c. Cutting and machining with Doty machine
5. Hole Cutting
a. Hole cutting with power-operated equipment
b. Hole cutting with drill, hammer and rasp
10
-------
6. Tapping operations
a. Dry capping with Mueller J. tool
b. Tapping operations with Mueller B-100 tool
7. Coupling removal
a. Removal of coupling with haircner and chisel
The above operations are representative of the activities routinely
performed at construction sites installing A/C pipe. Depending on the
magnitude of the job, any one or all of these operations may be conducted.
Although, all of these operations are fabricating processes, typically A/C
installation requires minimal field fabrication.
The operations identified, are performed intermittently and vary widely
in duration. Reportedly an average of only 1.1 percent of A/C pipe
installation time involves cutting, tapping or machining. ' This is
translated to approximately 5.3 man-minutes per day.'?
Measured concentrations during the unloading and laying of A/C pipe were
found to be 0.1 fiber/cm-*.^ The unloading activity involved the use of a
forklift which handled palletized pipe. Twenty centimeter (8 inch) pressure
pipe was arranged on 1.2 meter (4 foot) pallets, 8 per bed plus miscellaneous
short lengths and couplings. The material was unloaded in 15 minu'.es from a
truck carrying 16 pallets. The sample analyzed was obtained from i 24-minute
personal sample taken on the forklift operator.
The pipe laying operation involved trenching, laying pipe, and
back-filling simultaneously. Personal samples were taken on two men
performing the activity, one man in the trench at the forward end of the pipe
and the second worker, working both topside and in the trench. The second
worker attached a lowering clamp to the pipe, lubricating the pipe end, then
entered the trench to guide the pipe into place for coupling.
Personal monitoring of workers performing the operations listed above was
conducted to determine worker exposure to asbestos fibers. The results of the
monitoring activity are presented in Table 2. Only two operations, cutting
with abrasive discs and cutting and machining with a Doty tool without a
shroud, resulted in fiber releases greater than the OSHA 8-hr TWA* standard of
*TWA - Time Weighted Average.
11
-------
TABLE 2. RESULTS OK PERSONAL MONITORING OF EMPLOYEES PERFORMING A/C PIPE OPERATIONS 19
Average pea* exposures Ranges of 8-hour Cine-weighted average
(up to 15 nunit^s) conrentraiions
A/C s£w«r pipe A/C pressure pipe A/C Sftwer pipe A/C pressure pipe
Oaarci^r ' I.; I per 0?<.rj:ur Helper Opera Lor Helper Operator Helper
Operation (i/=---> l:A:L3) (I/1.-*3) (i/co3) (f/cn3) (l/ca3) (f/«3> (f/c->3) Contents
hack saw O.L8 «O.LO <0.10 0.11 <0.10a ND-<0.10 HD ND-<0.10 Sampling cine ranged from 12 Co IS miauCes.
A standard hack saw was used.
Snap cuLLirg -0.10 <0.10 <0.10 ND SC-<0.10 ND-«-0.lO ND ND A U'heeler chain cutter (Model 2990) was used
to make 5 to 8 cuts per sampling period (13 Co
16 ninutcs) .
.:-_»ixd disc. h-C ^2.10 10.20 65.00 49.20 A gas-poucred saw with a 25 cm dian^cer carbide
blade was used with a water delivery rate to
Che blade oE 2 Co 3 gallons per >ninute. Two to
three cues were made per sample period (3 Co 6
amutes).
•/.-••I • ui;;. d--_, 3>.>0 64.09 20i30 59.70 A gjs-pow«red aaw wi.ti a 25 cm diaucer caroide
Dladc wjs uicd LO oaiie unc cat per saaple period
(30 ta 45 seconds).
i'iL.0., .ufir 0.30 0.25 1.99 0.87 <0.10 <0.10 <0. 10-0.50 <0. 10-0.22 Tw» cuts (4 to 6 ra motet each) were sudc on the
j-id rasp sewer pipe; cuccing (one cue) Che pressure pipe
lasted 11 minutes.
ic. !i
.. ijii.e 0.1} 0.13 0.51 0.22 «O.LO <0.10 «0. 10-0. 12 <0.lO Twenty cm pipe uas cue using a Pilot ratchet
field lathe. Actual cutting time on toe sewer
pipe cook 2 minuces, cutting time on pressure
pipe lasCed 4 minutes.
P^-cf 1. cli*. -0.10 0.10 0.29 0.18 ND-<0.10 tfD-<0.10 <0.10 <0. 10-0. 14 Twenty cm pipe was cut using a Piloc electric
poured Field lache. Actual cutting tLae on tne
sewer pipe took 1/2 to 1 minute, cucn^g che
pressure pipe liatcJ 1-1/2 mnut«s.
lAitciu.. ^nd -.uhitiiig 3. S3 0.2^ 1.90 2.23 A Doty machine is custoa-nianufactured for
with Dot/ ji hme dry cutting and machining and has three operating
(continued)
-------
TABLE 2 (continued)
Average peak exposure* flanges ol 8-hour tine-weighted average
(up Co IS minutes) concentrations
A'C sower pipe A/C pressure pipe A/C sewer pipe A/C pressure pip«
Opera cor Helper Opcracor Helper Operator Helper Operator Helper
C:/cnJ) (i7cm3) (t/cxh if/en*) (f/cm3) U/cin^) (f/co3) (f/cn*)
•odes, dry. dry with shroud, and wet with
shroud. Two to four cuts and tvo to fo.r
LUC nut ing operations were completed per s*i=^ae
cycle. Saaple perioJs were as follows 3a=y
tool dry. pressure pip* 10 to 11 minutes azi
sewer pipe 9 to IS minutes, with dry shroji.
pressure pipe 13 to 17 minutes, and sau.tr pip*
12 to 14 minutes, with wet ahroud, pressure pipe
13 to IB minutes and sewer pipe 12 to 16 aio.
Dry j'.ruud 0.23 0.10 1.29 0.18 <0.10 ND-<0.10 <0.10-0.32 <0.10
•Mbt O.roid 0.20 0 10 0.21 0.27 0.10 0.13 ' NO <0.10 Tasting included one cut and one machining
operation. Actual cuLLing time lasted 2
ninuCi/s, machining lasted 10 "ounuteft.
-------
TABLE 2 (continued)
Average peck exposures
(up to 15 minutes)
Ranges of 8-hour I ime-weighced average
l/C sewer pipe A/C pressure pipe A/C sewer pipe
A/C
ipe
Oporalion
03*.»r»tor Helper Operator Helper Operator Helper Operator
(f/cnJ) (t/c.3J) (i/cn.3) (f/ca3) (I/en3) (C/cm3) (f/ca3)
Helper
(f/ca3)
Conmeat 5
0.23
0.13
0.22 <0.10
tit 1. 1 L,
a- d
<-r J :ool
operations
iller B-iOD
removal
-0.10
<0. 10
<0.10
<0.10
O.lt
0.10 ND- 0.10
0.13 NI>- 0.10
ND
K?*>vjl OL Cj.ir.Linj
witt1 nu^. er an^ chis
O. 10
ND
0.30
<0.10 ND- 0.10
ND- 0.10
center plug. Four holes were cut per staple
activity. It took 1 minute to cut a hole in
the sewer pipe and 1-1/2 co 2 minutes to cut a
hole in the pressure pipe.
Activity included drilling 1.6 cm holes in a
diameter, after which tne central portion was
knocked out with a hamner and the rough edges
smootned with a reap. Sampling tiaes, which
did not always cover the haiwaerLng aod reaping
operations, lasted 16 to 24 ainutes for
pressure pipe and from 17 to 21 ninutes Cor
sewer pipe.
NO-0.10 ND- 0.10 Miell:.- J tool is used for tapping pipe Cor
customer bervict. connectlanii. A manually
operated cool was used which cuts and threads
a hole. Two 2.) en holes were cue. Saaple
periods for the pressure pipe lasted 14 to 29
minutes; Cor sewer pipe IS Co 18 minutes.
HD-0.10 0.10 A Mueller B-100 tool is used for tapping pipes
already in place and containing water. Two
hole* were cut per sampling period, which for
both pressure and sewer pipe covered lA to 19
minutes.
0.10 ND- 0.10 A hammer and chisel were used Co cuke a
longitudinal trough in the coupling, aCterwhich
a crowbar was used to separate the cojpling.
For pressure pipe this took 22 minutes per
coupling. For sewer pipe tne process lasted 10
minutes. Later tests were performed when
couple removal lasted 10-30 seconds and 3 to 4
couples were removed.
a Jo ratine is reported when btitr values were <0.10 c/cra3.
•O " Not d..c«cc.'
-------
2 fibers/cm3. Theoretical TWA exposure ranges calculated assuming Che
duration of the operation ranged from 15 minutes to 2 hours, with the
remaining time calculated at zero exposure, are also presented in Table 2.
Based on these findings, the AACPP has published a field manual entitled
"Recommended Work Practices for A/C Pipe." Because of the widespread
acceptance of this manual, the American Water Works Association adopted the
same work practice recommendations and included them in their own work
practice manual.1*
Other exposure data that are based on laboratory glove box tests have
been reported in the literature. The results of A/C pipe testing by
GCA/Technology Division are presented in Table 3.20 Fiber concentrations
reported in the GCA study for A/C pipe sawing are similar to those found by
the AACPP study. The concentrations associated with hammering, however, were
substantially higher than those measured by the AACPP field studies. The
higher laboratory readings may be attributed to fiber accumulation in the
nonventilated air space of the glove-box chamber used in the testing program.
Additionally, because the AACPP operation was performed outdoors, the lower
levels recorded probably result from air dilution ani wind movement.
TABLE 3. RESULTS OF LABORATORY A/C SEWER PIPE8
PRODUCT TESTING PERFORMED BY GCA.20
Fiber concentration
Operation
Sawing
Sawing (repeat)
Hammering
Hammering (repeat)
Sample time
(minutes)
1
1
1
3
SEMb.c
(f/cm3)
_
65.1
20.6
7.3
Phase contrast0
(f/cm3)
59.4
56.5
19.8
12.2
aA 25 cm (10 in.) section of Johns-Manville sewer pipe having
a wall thickness of 1.6 cm (0.63 in.) was acted upon using an
electric circular saw equipped with an aluminum oxide blade.
^SEM - Scanning Electron Microscopy Analysis.
cFibers 5 urn or longer with a length to width aspect ratio of
3 or greater were counted.
With respect to A/C pipe handling operations, transportation poses little
threat of fiber release. If pipe is broken during shipment there is a
possibility for fibers to become airborne, although the fibers would likely be
bound in a cement mortar matrix. Prompt cleanup with the proper vacuum
equipment reduces fiber migration significantly."
15
-------
Beyond air releases, water transported through A/C pipe may carry
asbestos fibers into the homes of a great number of people. Several studies
on the asbestos fiber release from A/C pipe into potable water systems
conclude that the fiber increase in the water passing through these pipes is
slight.3,9-11 The amount of release is generally dependent upon the
aggressiveness of the water. The more aggressive a water is the greater its
potential to aid in the release of fibers from the cement pipe walls. The
aggressiveness of water is determined by factors such as pH, alkalinity and
calcium hardness.2L. Generally speaking, Che higher the pH, alkalinity, and
hardness of the water the less aggressive a water system is. According to
Millette et al.,21 16.5 percent of the U.S. water utilities are highly
aggressive, 52 percent are moderately aggressive and 31.5 percent are
nonaggressive. However, it has been noted that even those systems which carry
highly aggressive waters do not necessarily carry higher concentrations of
asbestos fibers. This phenomena can be accounted for by the following
factors:22
1. Type II autoclaved pipe is less susceptible to corrosion.
2. The majority of A/C pipe sold in the U.S. in the last 35 years has
been Type II pipe.
3. Zinc, iron, and perhaps magnesium and organic materials can have a
protective effect on A/C pipe.
Similarly, in the case of the enlargement or modification of existing
water pipeline systems, Millette et al.21 cite evidence that residents may
have been exposed to transitory increased asbestos levels in drinking water as
a result of improperly performed pipe tapping. This, however, should not
occur if the proper tools are used. Available tapping devices flush cutting
debris away thereby avoiding drinking water contamination and possible
airborne fiber release.
With respect to health effects, studies have concluded that asbestos
fibers consumed through drinking water do not appear to be intestinal
carcinogens in humans or other animals.I The amount of asbestos naturally
occurring in drinking water or added during passage through A/C pipes is so
small that one could not expect it to induce intestinal cancer; all
epidemiological studies are consistent with this view.l
Under certain conditions, it may be possible for asbestos fibers in water
to become airborne. For example, certain types of commercial and residential
humidifiers operate on the principle of atomizing water into forced heating
air. If it is assumed that the water supply to this type of humidifier
contains asbestos, it may be possible that the fibers are emitted into room
enclosures through heating ducts.^ The following hypothetical
calculation^- attempts to estimate the levels of asbestos which may be added
to indoor air as a result of humidifiers using water containing asbestos.
Levels of asbestos monitored in water supplies have ranged from LC-1 to as
high as 107 fibers/liter; also, aggressive waters can cause A/C pipe to
16
-------
raise asbestos levels Co the same ranges. For the purposes of this
calculation, the severe case is assumed that the asbestos water concentration
is 10^ fibers/liter. It is assumed that an atomizing humidifier is being
used by a homeowner, whose house contains roughly 400 m3 (14,000 ft3), and
is connected to the central heating system. The humidifier injects one liter
of water, containing 10? fibers/liter, into the heating system each hour.
Therefore, during the course of one day, the asbestos air concentration of the
house could theoretically be raised:
24 hr x 10 fibers/hr , .-5 ,., ,3 . . ... ,3 ,.. , 3
= *— = 6 x 10 fibers/m • 0.6 fibers/cm - 600 ng/m
400 in
This calculation is completely theoretical and is not based upon any indoor
air monitoring.^
17
-------
REFERENCES
1. Meylan, W. M., et al. 1978. Chemical Market Input/Output Analysis of
Selected Chemical Substances to Assess Sources of Environmental
Contamination: Task III Asbestos. Prepared for the U.S. Environmental
Protection Agency, Office of Toxic Substances, EPA-560/6-78-005.
2. Levine, R. J., Editor. Asbestos: An Information Resource prepared for
the U.S. Department of Health, Education, and Welfare. National Cancer
Institute. (NIH) 79-1681, May 1978. p. 63.
3. Hallenback, W., et al. Asbestos in Potable Water. University of
Illinois Water Resources Center Report No. 178, January 1979.
4. Pye, A. M. A Review of Asbestos Substitute Materials in Industrial
Applications, Journal of Hazardous Materials 4.1.2. 3(1979), p. 128.
S. Olson, H. L. Asbestos in Potable Water Supplies, Journal of American
Water Works Association. 66:515-518. 1977.
6. Suta, B. E., and K. J. Levine. Nonoccupational Asbestos Emissions and
Exposure. Asbestos Properties, Applications and Hazards, Volume 1, John
Wiley & Sons, New York, N.Y. 1979.
7. Survey of Water Main Pipe in U.S. Utilities Over 25,000 Population.
American City, Morgan-Grampian Pub. Co., Pittsfield, Mass. 1975.
8. Survey of Sewer Main Pipe in U.S. Utilities Over 250 Population American
City, Morgan-Grampian Pub. Co., Pittsfield, Mass. August 1975.
9. Kuschner, K., et al. Does the Use of Asbestos-Cement Pipe in Potable
Water Systems Constitute a Health Hazard? Journal of American Water
Works Assoc. 66:1-22. 1974.
10. Hue low, R. W., et al. Field Investigation of the Performance of Asbestos
Cement Pipe Under Various Water Quality Conditions. Prepublished copy.
Water Supply Research Division, Municipal Environmental Research
Laboratory, U.S. Environmental Protection Agency, Cincinnati, Ohio, April
1977, EPA-600/2-77-020.
18
-------
11. Craun, G. £., et al. Exposure to Asbestos Fibers in Water Distribution
Systems. Paper presented at the Ninth American Water Works Association
Conference, Anaheim, Calif. May 1977.
12. American Water Works Association. AWWA Standard for Asbestos-Cement
Transmission Pipe, 46 cm through 107 cm (18 through 42 inches) for watei
and other liquids. AWWA C402-77, January 30, 1977.
13. Clifton, R. A., Asbestos in 1978 Mineral Industry Surveys, U.S. Bureau of
Mines, Washington, D.C. August 22, 1979.
14. Cogley, D., et al. Life Cycle of Asbestos in Commercial and Industrial
Use Including Estimates of Releases to Air, Water and Land. Draft Repoit
Prepared by GCA/Technology Division for U.S. Environmental Protection
Agency, Office of Toxic Substances, Under EPA Contract No. 68-02-3168,
November 1981.
15. Research Triangle Institute, et al. Asbestos Dust. Technological
Feasibility Assessment and Economic Impact Analysis of Proposed Federal
Occupational Standards, Part I. U.S. Department of Labor, OSHA, NTIS No.
RTI/1370/02-01-F, September 1978.
16. LaShoto, P. W. GCA/Technology Division Trip Report on Visit to
Johns-Manville, N.J. October 22, 1979.
17. Clifton, R. A., Asbestos. 1980 Minerals Yearbook, U.S. Bureau of Mines,
Washington, D.C.
18. Epstein, A., Water and The Big Old City: Trouble Ahead. Knight Udder
Service, Boston Globe, p. 1. October 9, 1979.
19. Association of Asbestos Cement Pipe Producers, Recommended Standard for
Occupational Asbestos Exposure in Construction and Other Non-FixeJ Work
Operations. Internal Report, February 7, 1980.
20. Cogley, D., et al. The Experimental Determination of Asbestos Fijer Size
Distribution During Simulated Product Use. Draft Report Prepared by
GCA/Technology Division for U.S. Environmental Protection Agency, Office
of Toxic Substances, Under EPA Contract No. 68-02-3168. May 1981.
21. Milllecte, J.R., et al. Exposure to Asbestos from Drinking Water in the
United States, Health Effects Research Laboratory, Office of Research and
Development, U.S. Environmental Protection Agency, Cincinnati, Ohio,
August 1979. EPA-600/1-79-038.
22. McCullagh, S. G. Is There a Risk to Health in Using Asbestos-Cement
Pipes for the Carriage of Drinking Water. Ann. Occup. Hyg., 23(2)
189-193.
19
-------
SECTION 3
ASBESTOS PAPER
INTRODUCTION
Asbestos paper products include any product manufactured on a fourdrinier
or cylinder paper-making machine. Products in this category are all
manufactured using similar asbestos handling, product.ion, and emission control
equipment. The products do differ, however, in the amount of asbestos they
contain and their end-uses.
The 1980 consumption of asbestos fibers for the production of paper
products was estimated by the U.S. Bureau of Mines to be 90,020* metric tons
or 25.1 percent of all asbestos consumed in the United States. 1- Thus, it
ranks second to cement-pipe in the amount of asbestos consumed annually in the
United States. Asbestos paper products include eight general categories,
which are listed below in descending order of annual asbestos consumption
(category percentage):
• Flooring Felts (45)
• Roofing Felts (33)
• Beater-Add Gasket (9)
• Pipeline Wrap (5.6)
• Millboard (3.0)
• Specialty Papers (2.4)
• Commercial Paper (1.3)
• Electrical Insulation (0.4)
*this figure was arrived at by rearrangement of the Bureau of Mines (bOM)
data such that Paper Products would now include roofing and flooring felc
figures, which were extrapolated from BOM's roofing and flooring product
categories, respectively.
20
-------
The basic manufacturing operations are similar for most asbestos paper
products. The raw materials, which include asbestos fibers, binding fillers
and various other ingredients, are blended in a mixing operation. A pulp
beater or hoilander is used to mix the fibers and ingredients with water to
form a stock, which typically contains 3 percent asbestos fiber. This base
stock is stored in a container vessel (chest) until needed. Upon leaving the
storage chest, the stock is diluted to as low as 0.5 percent asbestos fiber in
a discharge chest. The amount of dilution depends upon the quality of the
paper being produced.2
The asbestos paper is now formed on either a fourdrinier-type or a
cylinder-type paper machine. The cylinder-type machine is more widely used in
the asbestos industry. Formed paper, carried along on a felt conveyor, is
dried by either applying heat causing evaporation or pressure, in the form of
rollers. The rollers squeeze the water out of the sheets. Catenaering
follows to produce a smooth side and then the paper is wound onto a spindle.
It is estimated that 60 percent of asbestos paper goes through some form
of secondary fabrication before reaching the end-user. Typically finishing
operations include slitting, sawing, punching, pressing, and laminating.
Typical asbestos exposure ranges during manufacture have been estimated at 1.0
to 3.5 f/cm3.3
The products contained in this category have a variety of uses in
industrial, commercial and residential settings. Most are used in
construction type work as an insulation/protector from the environment around
the object being built or installed. Others perform as insulators and/or
fire-retardants in appliances or some other type of apparatus which use
requires it to have the ability to withstand high temperature. While still
others are used as filters to purify liquids such as alcoholic beverages and
fruit juices.
In this report, only the major asbestos paper product groupings are
presented. While hundreds of individual asbestos paper products nay exist,
many are used in a manner similar to those described in the following
discussions and almost all originate from the same primary manufacturing
process.
FLOORING FELTS
Product Manufacturing and Composition
Asbestos is used in flooring felts to add dimensional stability and
resistance to moisture, rot, and heat.^ The asbestos flooring felts are
composed of about 85 percent asbestos and 15 percent latex binder.-' The
latex binder is normally a styrene-butadiene type, althougl acrylic latexes
have been used in the past.6 The type of asbestos used is 'chrysotile, with
shorter grades, grades 5 and 7, primarily being employed.
21
-------
Asbestos flooring felt is manufactured into a final consumer product by
coating one side of the felt with a resilient vinyl-type surface. The surface
coating applied is usually a plastisol or an organosol. The vinyl surfaces
are applied to the asbestos felt by various extrusion coating and laminating
and spread coating methods. After or during the coating operation, the
flooring is decorated to enhance its appearance. The vinyl sheet is then edge
trimmed by razor scoring or shear cutting and wound into a sheet product.
Flooring felt production accounts for 45 percent of the asbestos consumed
in the paper products category or about 40,509 metric tons per year in
I9601. From the period 1971-1975 the growth rate was estimated at 14.8
percent annually.-* Today, industrial sources indicate that the growth rate
for asbestos flooring felts will be minimal through 1985.5'6
Secondary and Consumer Use
Vinyl-asbestos sheet flooring felt is used in commercial and residential
applications. The asbestos felt backing is used because it adds dimensional
stability to the flooring, it is resistant to moisture and rot and has an
excellent fire protection rating.
During installation vinyl-asbestos flooring is cut to the size of the
floor area it is to be applied to. The cutting is accomplished using a razor,
knife, or shears. The subfloor is then coated with adhesives that secure the
vinyl-asbestos sheeting to the floor. All cutting and installations are done
by hand.
For certain applications asbestos felt is used without a vinyl surface
coating.*> Under these conditions, the flooring felt is adhered directly to
the floor, with final flooring applied on top of the asbestos felt. The final
flooring may be vinyl tile, vinyl sheet or carpeting. This type of
application is usually restricted to concrete floors where moisture problems
exist. The asbestos paper helps to transfer water to the walls.
The life span of asbestos-containing flooring felt is dependent on the
amount of traffic the surface layer must withstand. It has been estimated
that a normal life span is between 10 and 30 /ears. During the life 'of the
flooring, the top coat will be worn away by prolonged wear. The surface
material is usually replaced long before the vinyl foam layer or size coat are
lost to expose the underlying felt.?
Environmental Release
During normal use, few or no asbestos fibers are released from
asbestos-containing flooring felt. The fibers are considered locked-in; that
is, the fibers are sufficiently bonded to one another by inorganic cements,
thermosetting polymers, thermoplastic resins, or elastomic compositions such
that they cannot be readily separated or removed from one another or the
product during normal product handling and use. During installs ion the
vinyl-asbestos sheet flooring is cut with sharp knives or scisso-s at which
22
-------
time few fibers are expected to be released.? The adhering of vinyl sheet
flooring on top of the felt further isolates the asbescos fibers from the
environment.
Foot traffic moving over the flooring and continual washing, wears away
the vinyl coating, but does not wear down to the asbestos containing flooring
felt. By the time the surface layer starts to wear away the floor design is
lost and the flooring would mostly like be replaced.
Environmental release of asbestos fibers may occur during the removal of
old, worn out vinyl sheet flooring. Although the back of the felt is
generally covered with adhesive, it is possible in some instances to have felt
pieces split apart and remain attached to the floor. Fibers in the residual
pieces remain bound in the flooring felt by the resin matrix. Removal of the
residual pieces adhering to the floor by sanding, however, could release
asbestos fibers to the ambient environment. Few or no fibers are expected to
be emitted, however, if the material is thoroughly wetted prior to scrapping
or sanding.
Asbestos fiber release during the installation and removal of vinyl sheet
flooring has been monitored. Table 4 presents the results of tests conducted
for the Resilient Floor Covering Institute (RFCI) by SRI International. As
shown, fiber releases are well below the OSHA TWA limit of 2 fibers/cm-*.
ROOFING FELTS
Product Manufacturing and Composition
Asbestos roofing paper consists mainly of 85 to 87 percent asbestos along
with 8 to 12 percent cellulose fiber and 3 to 5 percent starch binder.5 The
paper is made in either single or multilayered grades and may have fiber glass
filaments or strands of wire embedded between paper layers for reinforcement.
Chrysotile asbestos, grades .6 and 7, are principally used for making roofing
felts. The felts are converted into conventional roofing products by
saturation of the felt with asphalt or tar.
Roofing felt production accounts for 33 percent of the asbestos
consumption in the paper products category or an estimated 29,707 metric tons
in I960.1 Industry sources believe the raarkec had peaked in 1979.^ It is
expected that the market will decline at a rate of slightly less than the 5
percent per year between 1982-1985.5>6 The two major reasons for the
expected decline are:
1. Competition from fiberglass roofing, and
2. Labor unions^ and the construction industries^ apprehension
about using asbestos-containing products.
23
-------
TABLE 4. ASBESTOS FIBER CONCENTRATIONS ASSOCIATED WITH THE INSTALLATION
AND REMOVAL OF VINYL SHEET FLOORING BACKED WITH ASBESTOS
FLOORING FELT3
Site description
Age of vinyl sheeting
and method of attachment
(years)
Operation
Measured asbestos
TWA rangeb
(fiber/cm3)
Residential
Residential
Residential
Residential
Residential
Residential
Residential
Residential
Residential
Residential
Residential
Residential
home
home
home
home
home
home
home
home
home
home
home
home
- kitchen
- kitchen
- kitchen
- foyer
- kitchen
- kitchen
- foyer
- kitchen
- kitchen
- kitchen
- kitchen
- kitchen
New adhered
6-adhered
13-adhered
2-adhered
8-unadhered
13-adhered
2-adhered
8-unadhered
6-adhered
6-adhered
6-adhered
6-adhered
Installation
Installation
Installation
Installation
Installation
Partial removal0
Total removalc
Total .removal0
Wear layer removal
Wet scrape felt
Dry scrape felt
Dry scrape felt
layer
layer
layer
0.
0.
0.
0.
0.
0.
0.
0.
0.
1.
0.
01
06
01
03
02
04
01
08
41
12
83
to
0
to
to
to
to
to
to
ro
0.
0.
0.
0.
0.
0.
2.
1.
02
07
06
10
04
16
03
06
aSource: Comments on the advance notice of proposal rulemaking on the commercial and
industrial use of asbestos fibers. The Resilient Floor Covering Institute. Washington, D.C.
February 18, 1980.
''Values have been rounded by GCA/Technology Division.
cOperation:.'were performed according to Resilient Floor Covering Institute practices that do
not include sanding, sweeping, or dry-scaping.
-------
A 47 percent drop from 1978 to 1980 was mainly attributed to poor
economic conditions in the construction industry. *• An extended 20 year
forecast projects an annual asbestos consumption rate of 15,520 metric
tuns.'- This forecast was developed prior to the release of 1980 asbestos
figures.
Secondary and Consumer Use
Asbestos roofing paper is used on all types of buildings, whether they be
commercial, residential, or industrial. Two types of roofs primarily use this
material, built-up roofs and roofs that need an underlayment. More than 60
percent of asbestos roofing paper is utilized in the reroofing industry and
the remainder is for new construction.
There are three basic types of built-up roofs; gravel surface, mineral
surface, and smooth surface. Built-up roofing material is usually prepared at
the project site. The asbestos roofing felt is cut to.required sizes and
shapes using razors, knives or shears. Strips of paper roofing are then layed
on top of each other with hot asphalt or tar spread between the layers to
provide adhesion and weatherproofing. The built-up roofing is attached to the
roof's deck by tar (adhesion) or is nailed down. After laying the last strips
of asbestos roofing felt, the roof surface is covered completely with a coat
ot asphalt, onto which gravel or ground minerals are applied.
As an underlayment for other roofing materials, asbestos roofing felt is
attached to the building surface with adhesives, such as tar or asphalt, or by
nailing. The asbestos felt is then covered with shingles, cement sheets, or
other forms of roofing material.
Built-up roofs comprised of asbestos roofing felts have an expected life
span of at least 20 years.' With an aggregate surface application, the roof
will reach a point of failure and require refurbishing prior to any direct
exposure of the enclosed felt. Older smooth-surface roofs, however, may
weather to a point where the asbestos fibers are exposed.
Environmental Release
Asbestos fibers contained in roofing felts are bound within the product
matrix. The degree of bonding as determined by the latex resins and the
asphalt should be adequate to essentially eliminate any liberation of fibers.
During installation the asbestos paper roofing is cut with sharp knives or
shears.' The attaching of the roofing felts to the roof deck with asphalt
or tar further isolates the asbestos fibers from the atmosphere and the
effects of weathering.
As stated above, the weathering of the roofs is dependent on the type of
surface covering. A mineral (gravel) surface wears in such a way that it will
reach a point of failure prior to the exposure of the roofing felt material,
while a smooth surface roof may wear to a point where the roofing felt will be
exposed. Under the latter condition, the breakdown of the top coat exposes
25
-------
the underlying felt, which can release asbestos fibers by wind and water
erosion. The top layer of felt reportedly remains intact for a period of many
years indicating a slow degradation with extremely low levels of fiber
release.7
The potential for asbestos fiber release during the removal of worn-out
roofing material is minimized because the fibers are bound within the roofing
matrix. In addition, an asphalt top covering on the roofing felts keeps the
top layer together and protects the material from surface weathering.
Asbestos fibers have been detected (0.007 to 0.54 f/cm3) in the ambient air
surrounding a roof removal work site.° It was not determined whether the
asbestos detected was due to the removal work or represented ambient
background levels.8 During the removal process, old roofing material was
cut into small 0.19 square meter (2 feet square) sections using a circular saw
and then ripped up using shovels.
BEATER-ADD GASKET
Product Manufacturing and Composition
There are two major types of asbestos-containing gaskets, compressed
sheet and beater-add sheet. Compressed sheet gaskets will be discussed in
Section 6 under Gaskets and Packing. Beater-add asbestos paper gaskets
consist of 60 to 80 percent asbestos fibers and 20 to 40 percent binder,
usually a latex compound.*> Almost all beater-add gaskets are formulated
using various grades of chrysotile asbestos. The chemical composition of the
binder used determines the suitability of the gasket to its end use
application. Beater-add gaskets are so named due to the fact that the binder
is added during the beater process of the production steps.^
Heater-add gaskets are usually produced in sheet form or sheet-roll
form. Thicknesses vary from very thin paper to that resembling millboard, 0.6
to 1.3 cm (0.25 to 0.5 in.) thick. Beater-add gasket paper is sold in this
form to secondary fabricators. The fabricators 'cut-out* the gasket material
to sizes and dimensions specified by their customers. The gasket material can
then be used as is or it can be modified by aoding reinforcements such as wire
inserts or sheading the paper with metal foils, plastics or cloth.^
The amount of asbestos consumed annually to manufacture beater-add
gaskets is 9 percent of the total amount consumed by paper products or abouc
8,100 metric tons.'- Throughout the early '70s, the growth rate for asbestos
paper gaskets has been roughly 9.8 percent per year and was expected to
continue at that race into the future.5 In 1979, manufacturers were still
projecting continued growth but at a rate less than the 9.8 percent annual
increase predicted by Little, 1976.^ The reason for such a strong growth
rate is that there are few competitive products.
26
-------
Secondary and Consumer Use
Beater-add gaskets are used in Industrial and commercial applications to
obtain a tight seal between two rigid elements such as connections between
piping, covers, joints and openings of all types.* The major industrial
user of this type of gasket is the automotive industry. The material is used
as head gaskets, carburetor gaskets, manifold gaskets, and oil and
transmission gaskets, to name a few." In addition, asbestos gaskets are
widely used in other transportation applications, such as trains, airplanes,
and ships. Further, they are used in a variety of industrial and commercial
equipment, including heat exchangers, boilers, furnaces, and pipe
connections. The chemical industry uses asbestos gaskets extensively for
equipment connections because of the chemical inertness of asbestos.^
Prior to installation, the asbestos-containing paper material (roll form)
is die-cut to form gasket shape. The gaskets are normally cut at a
fabricating shop although some could be cut by hand at the job site for
specific applications. Since a gasket is designed to fit between two
adjoining elements, its faces are never exposed; i.e., they are completely
isolated from the ambient environment.
The life span of a gasket is dependent on the severity of use and
maintenance practices. It has been estimatedJ that 25 percent of the gasket
materials consumed annually have less than a 1 year useful span, 60 percent
are used for maintenance and long-time replacement, with the remaining 15
percent for new installation.
Environmental Release
Asbestos fibers contained in the gasket material are locked in the
product matrix and therefore are not readily dislodged during normal
handling. Measured asbestos fiber levels resulting from secondary fabricating
operations such as cutting and packaging have ranged from 0.1 to 0.5
fiber/cm-*.^ No fiber release is expected during material installation
because the gaskets have been precut to size and in many cases covered with an
adhesive sealant.
Asbestos release during a gasket's useful life time is extremely small
because the faces of the gaskets are isolated from the environment as are the
edges since most are usually covered with metal.
The removal of the gaskets is not a source of asbestos fibers if the
gasket is removed in one piece. If any portion sticks to the surface it is
usually scraped off. This action is not expected to liberate asbestos fiber
because the bonding material should remain intact. However, if it is dry and
brittle, fiber release is possible. Should sanding be required to remove the
asbestos gasket, wetting it down prior to commencement of the activity will
reduce the potential for fiber release. No asbestos fiber release data have
been reported for beater-add gasket use activites.
27
-------
PIPtLINE WRAP
Product Manufacturing and Composition
Asbestos pipeline wrap is manufactured by a process similar to that
employed to manufacture roofing felts. During processing, the pipeline wrap
LH pulled through a bath ot hot asphalt or coal tar until it is thoroughly
saturated. After saturation, the paper passes over a series of hot rollers to
allow the asphalt or coal tar to permeate the paper. Following impregnation,
the felt is air dried, rolled and packaged for sale.
The amount of asbestos used to manufacture pipeline wrap represents 5.6
percent of the asbestos consumed in the paper product category, or about 5,041
metric tons per year.1 The predicted future for new pipeline construction
is one of continued strong growth. However, competitive alternatives to
asbestos wrap, such as plastic wrap, epoxy resins, and extruded coatings, are
becoming more available, therefore increasing competitive pressures.11 Cost
effectiveness is still in favor of asbestos pipe wraps. Although, with the
rapidly rising cost of asbestos fiber and coal tar products, the advantage
will begin to shift away from asbestos." Consequently, growth rates may
decline or stagnate over the next few years.
Secondary and Consumer Use
Asbestos paper wraps are used by industries and municipalities to protect
underground pipelines from corrosive soil, chemicals, rotting, and decay. The
major user of asbestos wraps is the oil and gas industry. Other industries
such as the chemical industry, with underground steam and hot water piping,
use asbestos paper wrap because of its rot resistant property. The life span
of the underground asbestos pipe wrap is the same as the pipe it ;s wrapped
around. Very seldom if ever is a pipe rewrapped unless it is damaged.
Asbestos paper wrap use above ground is minimal. The only reported use is for
cooling towers where rot and decay are also a problem. ^
Installation of the asbestos paper wrap is usually done by machine
winding. Hand winding is used only for special field fabrication or damage
repairs. The wrapping paper can be attached or bonded to the pipe surface by
special adhesive coatings or by hot enamels which are coated to one side of
the paper. The coatings or enamels also aid in the corrosion protection of
the pipe.
Environmental Release
Because the fibers are bonded by the latex binders and then further
locked in by an asphalt or coal tar coating, the release of asbestos fibers to
the atmosphere is expected to be minimal. Laboratory experiments simulating
pipeline wrap removal activities have been performed by GCA." Monitoring
results of fiber release from cutting, tearing, and crumpling activities are
presented in Table 5. As shown, cutting and tearing caused no or a minor
amount of fiber release. Crumpling, however, did increase the measured air
concentration to a level above OSHA's 2 fiber/cm-* TWA standard. The
28
-------
simulated activities were performed in a nonventilated glove box chamber.
Such a sampling environment may have resulted in increased fiber levels due to
fiber accumulation in the confined air apace.
TABLE 5. ASBESTOS FIBER8 CONCENTRATIONS ASSOCIATED WITH
SIMULATED PIPELINE WRAP REMOVAL ACTIVITIES13
Activity
performed
Cut
Tear
Tear
Crumple
Crumple
Duration
(minutes)
1
1
3
3
U
Phase contrast analysis
(f/cm3)
0
0
0.9
1.9
14.5
SEMb analysis
(f/cm3)
0
0
0
6.1
6.1
aFibers counted were >5 urn in length and had a length to width
aspect ratio of 3 or greater.
''Scanning electron microscopy.
As stated above, attachment of the wrapping paper to piping is done by
machine with special adhesive coatings or hot enamels. During application
there should be no release of asbestos fibers since the material remains
intact. Also, the binders and the asphalt or coal tar add extra strength to
hold the material together. For these reasons, once the wrapped pipe is
installed, there should be no fiber release to the environment.
MILLBOARD
Product Manufacturing and Composition
Millboard consists of 60 to 95 percent asbestos and 5 to 40 percent
binders. Chrysotile is the most common type of asbestos used, with grade 5
preferred." The binders are usually portland cement and starch. Clay,
limestone, mineral wool, and several other materials are frequently used as
fillers or to provide special qualities. The amount of each material used in
production varies widely. Purchasers frequently specify the ingredients and
composition of the millboard they want to ensure that the product meets their
requirements.
Millboard is manufactured in individual sheets, this being the only
difference from the continuous sheet production of asbestos paper. The
process uses a wet cylinder paper machine equipped with one or two cylinder
sereins, conveying belts, pressure rolls, and a cylinder mold. A cylinder
rotaiing in a vat of slurry picks up the fibers which are removed from the
cyliider and drawn through a press for partial dewatering. The sheet is wound
29
-------
on another cylinder until the desired thickness is achieved, at which time the
built-up layer is cut and peeled off the cylinder. The sheet is then dried
until it contains 5 to 6 percent water.^
Rollboard, a form of millboard, differs from millboard in that it is chin
enough to permit flexibility. Rollboard, however, cannot withstand
temperatures greater than 177°C (350°F) because of its thinness and starch
binder composition.
Millboard production accounts for 3 percent of the asbestos consumed in
the paper products category, or about 2,700 metric tons.^- The outlook for
increased millboard production is unclear. In the mid to late seventies,
millboard production was predicted to grow at an annual rate of 0.9 to
1 percent through 1985.5 Today, millboard production is predicted to
decrease, as manufacturers find acceptable and economical substitutes. This
is presently the situation for heat and flame protection applications. The
gasket application of millboard is currently stable because there are no
substitutes for it.
Secondary and Consumer Use
Millboard is used for a variety of industrial, commercial, and
residential applications. Finished millboard is purchased by (1) secondary
fabricators who install it or incorporate it into other products,
(2) industrial distributors who supply such operations as steel mills and
glass factories, (3) construction workers as building material, and
(4) asbestos specialty houses.°
Millboard used for boiler gasket applications is usually die-cut by a
secondary manufacturer, but if a special design is needed, the material may be
cut by the product consumer. Millboard is also used as a filler for metal
reinforced gaskets, which are frequently used on small air-cooled engines such
as lawnmowers. Another application includes gaskets used for laying pipes at
aluminum plants.
Millboard use as a flame or heat barrier has increased with the upsurge
in wood and coal burning stoves in residential settings. It is also used in
the manufacture of prefabricated fireplaces. Residential uses extend to the
linings of safes, stoves, heaters, and electrical switch boxes, stove pipe
rings, stove mats, and table pads.
Commercial applications include heat or flame barrier shields for welding
and soldering operations, office partitions, and fireproof wallboards.
Industrial uses, which are numerous, include mats to place hot products on,
linings for furnaces, oven insulation, sealings for holes and flues in roofs
of furnaces, thermal door gaskets, and heat protection walls.
'n both the glass and steel industries, millboard rolls and discs are
used 10 convey flat glass or annealed or pickled steel from one point in the
manufacturing process to another. Millboard is used because it is heat
resistant and it does not disfigure the product.
30
-------
Millboard is also used by manufacturers as slip planes to insulate the
silica furnace linings of an induction furnace. When the silica lining wears
out nnd needs to be replaced, the millboard must also be replaced. ,
In summary, millboard is one of the most widely used asbestos-containing
products. Its numerous applications are listed in Table 6. Attributes that
make it so versatile include the way in which it can be acted upon during
installation; millboard is easy to cut, can be punched into shape, and can )e
wet molded and is compressible.
The useful life span of a piece of installed millboard is indeterminable
because of its varied uses. Depending on its application, a piece of
millboard could have a short life expectancy as a result of being the lining
for an induction furnace or a long life expectancy as a fire barrier liner of
a door or wall partition.
Environmental Release
Asbestos fiber release from handling millboard is related to the
material's composition and its end use. Peak fiber releases from handling
millboard will occur during preparation for installation, including cutting
and shaping, and removal, especially if the millboard needs to be scraped
off. Because the asbestos composition of millboard can vary greatly, the
potential and magnitude of asbestos fiber release change accordingly.
Installation of millboard requires it be cut to size to accommodate its
intended use. Cutting is accomplished using a saw, knife, or shears. In a
controlled laboratory glove box test," scoring and sawing of millboard
resulted in measured fiber levels of 8.4 and 6.2 fibers/cm-*, respectively,
as determined by scanning electron microscopy (SEM) analysis.
With respect to fastening millboard to support structures, adhesives,
nails, or bolts are used. When used for an enclosed application, such as the
top or side panels of an oven, the millboard may simply be held in place by a
metal guide frame. To simulate the fastening activity, a piece of millboard
was subjected to hammering for 10 minutes. Again, this test was performed in
a laboratory controlled glove box. The resultant monitored fiber level was
reported to be 1.4 fibers/cm-' as determined by SEM. In all three of
these cited tests, the glove box results may be higher than those one would
expeci under actual field conditions. Fiber accumulation in the nonventi.lated
air s >ace of the glove box chamber could account for the relatively high fiber
level ; recorded.
Once installed, asbestos fiber release from millboard should be minimal.
In the case of millboard gaskets, both faces are normally isolated from the
external environment and the edges are usually covered. Millboard used as a
fire retardant or insulating barrier is normally enclosed in walls, ceilings,
and doors, thus preventing any asbestos fiber release to the environment. The
same is true for millboard slip planes, in that the millboard is usually
contdined within a finite space. Once installed for insulation, it is
expected to last indefinitely.
31
-------
TABLE 6. INDUSTRIAL, COMMERCIAL, AND RESIDENTIAL USE OF
ASBESTOS MILLBOARD AND INDIVIDUAL APPLICATIONS12
UklT
Individual application
ElcclrLCnl
Apiili.inei-
Aluminum
Harini>, shipyard, airrraft
Found ry
bteel
Metal lurfjicAl
Ceramic
CUia
Commercial
Hctal-clad doori
Offiif pardtione
Soldviing fixtures and aoldanng bloeka
Spnrk mid blare ehielila in welding ihopi
Firpprout wallboard
Waahcm in electrical apparatua
Linings fur safes, drycleaninK nachines.
incinuralora, heater rooms
Garage paneling
Linint;n for liume aofcn, otnvrA, heatera and
electric awitch boxea
Tent shields
Stove pi [ic rings
Stove mula, mble iiaJs0
Porfumo riiiga for oil Inmpa
In boilers, ai naakeci. wliuli nay be natal reinforced, a* flaoe and
heal l»arriom, la alip*plani r and trough liner
Liner for containe that catches hot netal fron cutting operations
Trough liner and i.on trough cover
Backup insulation for furnace lining
Uaed,between the hot mandrel and the bearing ahell in molten babbitt
operation
Low maaa kiln cara
Aa inaulation in glaaa tank erowna, melter, refiner, aidewalla, etc.
Between outside metal and wood core
uetwecn metal aheeta, valued aa a fireproof ing and Bound deadening
material. Very large potenti.nl market
'Millbu.inl it nr longer un.'J in toaitcra ai . lenient bonrda for wire mentation. It haa been replaced by reconatituted
mica.
32
-------
In the steel and glass industries, millboard rolls or discs are subjected
to extensive wear. Based on an extensive literature search, the amount of
asbestos fibers released from such activities has not been determined yet.
Removal of millboard has the potential to release asbestos fibers. The
amount of release is estimated to be similar co, if not more than, the release
expected during installation.
SPECIALTY PAPER PRODUCTS
There are six major types of asbestos specialty paper:
• Cooling tower fill
• Transmission paper
• Beverage and pharmaceutical filters
• Electrolytic diaphragms
• Decorative laminates
• Metal linings
Other specialty paper products are produced, but asbestos is used in
minimal amounts.
Cooling Tower Fill
Product Manufacturing and Composition—
Cooling tower fill is manufactured using a base paper consisting of two
grades of chrysotile asbestos and a few different latex binders depending or
the manufacturer. The base paper (90 to 91 percent asbestos) is sold to the
tower fill manufacturer who saturates it with thermosetting resins. Fluted
sheets, formed by preceding operations, are then bonded together to form
packs, the edges of which are normally reinforced. In use, the corrugated
surface of each section of paper increases the surface area of the water film
passing over it, thereby improving cooling efficiency.*>
The amount of asbestos paper being used as cooling tower fill is
decreasing." However, in those applications where high heat and cnemical
resistance are required, asbestos-containing tower fill will continue to be
used. In 1976, it was found that several thousand tons or asbestos fiber were
consumed annually to make cooling tower saturates.5 Although consumption
figures are not available, the amount of asbestos fiber used since 1976 has
been declining and is presumed to continue to do so. One reason for the
decline in consumption is that asbestos paper and processing is becoming Co«
expensive when compared to readily available substitutes.
33
-------
Secondary and Consumer Use—
Asbestos-containing cooling tower fill is an industrial product, not a
consumer product. Asbestos is used to manufacture cooling tower fill because
of its heat and chemical resistant properties. The installation process
simply involves attaching the fill material to the inner walls of the cooling
tower. The Life span of the cooling fill is not known, but it is expected to
be as long, if not longer, than that of other asbestos paper products.
Environmental Release—
During processing, the asbestos paper is saturated with an oil-based
product, cut to size, and then layered. As a result of this treatment,
asbestos fiber release during handling and use is expected to be minimal. A
study14 of the pollution potential from cooling towers using asbestos paper
fills indicated virtually zero asbestos release to the environment.
Transmission Paper
Prodict Manufacturing and Composition—
Asbestos transmission paper is a latex-based product made with chrysotile
asbeftos.° The base transmission paper is saturated with phenolic resins to
create a very hard and resilient product. After saturation and hardening, the
papei product is then cut to required sizes in the shape of discs. The
aver, ge automobile with an automatic power shift contains from 8 to 12 of
thesi- paper-lined discs. In 1977, an estimated 900 tons of asbestos fibers
were consumed in the production of automatic transmission paper.^ Present
consumption and future projections are not available.
Secondary and Consumer Use—
Transmission discs are industrial and limited retail products. The
genei al consumer population would not normally be involved in handling such
products. Installation of the discs would take place at automotive assembly
plants or local service garages. With respect to use, the discs are enclosed
within the transmission housing and are coated with a. lubricating oil to
reduce friction wear. These two factors virtually eliminate the potential for
environmental fiber release during use. Wear of the discs depends on the
amount of slippage during gear shifts. Once the transmission can no longer
hold a gear shift, it must be repaired or replaced.
Environmental-Release—
Because the asbestos-containing paper is impregnated with a phenolic
resin before being cut to size, the amount of asbestos material released is
expected to be minimal during installation. As stated above, during use, the
asbestos transmission paper is completely isolated from the environment.
Asbestos release while repairing or replacing the transmission or its parts
should also be minimal as discs are coated with a transmission fluid when they
are removed. No monitoring data for transmission paper use or handling was
discovered during the literature search.
-------
Beverage and Pharmaceutical Filters
Product Manufacturing and Composition—
Asbestos filters used in the beverage and pharmaceutical industries are
made on a conventional fourdrinier papermaking machine." The amount of
chrybotile asbestos used varies from a high of 50 percent for pharmaceutical
grades to as low as 5 percent for rough filtering applications.12 The
asbestos used for filters is a very high purity grade. Other filter
constituents include cellulose fibers, various types of latex resins, and
occasionally diatomaceous earth. In 1979, the estimated quantity of asbestos
fiber consumed to manufacture asbestos-containing filters was 90 metric
tons.11 This is down from over 900 metric tons annually in the early
1970*3, and forecasts are for the disappearance of asbestos filters as more
cost-effective substitutes are developed.11
Secondary and Consumer Use—
Asbestos-containing filters are used primarily by the beer, wine, and
liquor industries. As recently as 1979, about 30 percent of the wine, 10
percent of the beer, and 25 percent of the distilling producers used some form
of a .bestos filtration.^ Asbestos paper filters are also used for specialty
applications in the cosmetic and pharmaceutical industries and for the
filtration of various fruit juices. Again, these uses are primarily
industrial and not general consumer. The life span of filters varies from a
one-time application to being used until they are clogged or no longer
effectively filter out undesirable materials.
Environmental Release—
Asbestos fiber release during asbestos filter use has been monitored
extensively to identify potential health concerns. Gaudichet et al.1-*
tested 42 different types of wines before and after filtration and found 15 to
be significantly positive for chrysotile asbestos. Concentrations ranged from
2 to 60 x 106 fibers/liter. Table 7 presents a comparison of the results
from the six samples tested after undergoing various common filtration
processes.
Electrolytic Diaphragms
Product Manufacturing and Composition—
Asbestos fibers are used as a filtering medium in an electrolytic process
that produces chlorine and caustic soda. The process involves the
electrolysis of a brine solution whereby chlorine is produced at an anode
element and hydrogen, together with sodium hydroxide, at a cathode element.
Diaphragm cells coated with asbestos fibers are used to separate the anode
from the cathode element. With use, the diaphragm becomes cloggea with
migrating particles. When the efficiency of the cells drops off, the
diaphragms are removed from the cells and renewed. The useful life span of a
cell will vary depending on use but can last from 6 months :o 1 year.
35
-------
TABLE 7. ASBESTOS CONTAMINATION IN FILTERED WINES*5
No.
Filtering process
Number of
asbestos fibers
Mean lengtli
(jjm)
Other particles
Original wine
Filtration with continuous
injection of filter additive
ASBESTOS + DIATOMITE
24
2.5
2.7
Diatomite remains and
sone phyllosilicates
Diatomite remains
Filtration with continuous
injection of filter additive
CELLULOSE + DIATOMITE
Normal pad filtration
ASBESTOS sheets
Sterilized pad filtration
ASBESTOS sheets
Normal pad filtration-
CELLULOSE + DIATOMITE
sheets
0.8
46
nda
1.6
1.1
Many diatomite remains
Exceptionally numerous
diatomite remains and
phyllos.ilicat.es
Exceptionally numerous
diatomite remains
Diatomite remains and
phyllosilicates
Sterilized pad filtration
CELLULOSE + DIATOMITE
sheets
0.8
0.6
Diatomite remains and
phyllosilicates
and = Fiber not detected.
-------
The renewal operation typically involves immersing the cell diaphragm
(a perforated steel plate) into a vat containing a homogeneous mixture of
asbestos and cell liquor (sodium hydroxide and sodium chloride). A vacuum is
drawn through the immersed diaphragm, pulling the asbestos onto the steel
plate to form the filtering surface. After the diaphragm has been coated
(~0.3 cm thick), it is removed from the vat and dried by continuing to pull a
vacuum across the filtering membrane.
At present, almost all industrial diaphragm cells are made using an
asbestos slurry, with a minor amount using asbestos paper. Johns-Manville is
reportedly still manufacturing a high quality paper for diaphragm cell renewal
purposes." The paper is comprised of special long-fiber asbestos and is
available in various weights from 58 to 146 kg/100 m2 (ca. 12 to 30
lb/100 ft2). Yearly asbestos consumption figures for electrolytic diaphragm
renewal are not known. The majority of consumption is for asbestos slurry
generation and not specialty diaphragm paper production.
Secondary and Consumer Use—
Asbestos use during electrolytic cell renewal is strictly an industrial
application and represents an occupational safety hazard. Human expsoure is
not expected beyond the production room environment.
Environmental Release—
Information concerning the release of asbestos fibers during electrolytic
diaphragm cell renewal is scant. Once added to the slurry, the asbestos is in
solution and should not become airborne. Removal of the spent filtering
membrane from the diaphragm is accomplished by washing the material off the
plate using water under high pressure. The waste asbestos material, in a
wetted state, is then cleaned up and containerized for ultimate disposal. The
high moisture environment also suppresses airborne fiber release, thus
minimizing exposure.
Decorative Laminates
Product Manufacturing and Composition—
Decorative laminates are a specialty use paper which is completely
saturated with a thermosetting. resin. The laminates are made from a
latex-bound asbestos paper. The laminated sheet is formed by heat curing
successive layers of paper that have been saturated with a thermosetting
resin. Due to the concern of working with asbestos minerals and the
availability of substitutes, asbestos-containing paper has not been used to
produce decorative laminates since 1979.6
Secondary and Consumer Use—
Decorative laminates can be bonded co plywood, fiberboard, or metals. It
can be sawed, drilled, or sanded using conventional woodworking tools.
Asbestos decorative laminates have been used where Class 1 fire resistanc
ratings were required. They have been applied to wall or ceiling paneling,
desktops, countertops, or worktable tops.
37
-------
Environmental Release—.
Release of asbestos fibers during handling and applying decorative
laminates is expected to be minimal because the asbestos fibers are initially
bonded in the asbestos paper and then the paper is saturated with either a
phenolic or melamine thermosetting resin. No monitoring data were discovered
during the literature search.
Metal Lining Paper
Product Manufacturing and Composition—
Metal lining asbestos paper is manufactured for use as a corrosive
protecting layer attached to metal siding products and culvert pipe products.
The asbestos paper lining is manufactured similarly to commercial paper except
this paper contains a higher percentage of binder and a smaller percentage of
clay." Production rates for this product are very stable, and decreases in
the near future are not expected.
Secondary and Consumer Use—
The metal lining asbestos paper is sent to a secondary manufacturer where
it is attached to building siding and culvert pipe. Typical applications
include building siding and roof paneling in the chemical industry and
building siding for other industries exposed to corrosive conditions. Culvert
piping is used in sewage sanitary landfill applications, which require the
safe transport of corrosive liquids.
Environmental Release—
Atmospheric release of asbestos fibers is essentially limited to cutting
the paper to size at the secondary manufacturing plant. The magnitude of the
release is expected to be similar to that expected for cutting commercial
asbestos paper (see below).
COMMERCIAL PAPER
Product Manufacturing and Composition
Commercial asbestos paper spans a wide range of product applications,
including general insulating paper, muffler paper, and corrugated papers, all
varying in weight and thickness. The compositon of the general insulating
paper is normally 95 to 98 percent asbestos fiber and 2 to 5 percent starch
binder.^ The types of asbestos used are short and medium grades of
chrysotile.
With specific reference to muffler and corrugated paper, muffler paper
consists of a very high percentage of asbestos fiber and only a small
percentage of starch binder. The surface of the paper 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
starch binder.
38
-------
Manufacturing of commercial asbestos paper is done on conventional
papermaking machines which produce sheetrolls or tapes as finished products.
The manufacturing of corrugated paper differs only by the addition of a
corrugation machine that produces the desired corrugated molding of the paper
surface.^
Commercial asbestos paper production accounts for 1.3 percent of the
asbestos consumed annually in the paper products category, or about 1,170
metric tons of asbestos in 1980.1 In 1975, the amount of asbestos used was
much larger; muffler paper and corrugated paper each used over 3,000 metric
tons. In 1977, the estimated production of corrugated paper was down to
approximately 2,500 tons. The decline of these products has been caused by
the consumer's desire to use a reasonably priced substitute containing no
asbestos. Consequently, there has been and probably will continue to be a
negative growth rate for commercial paper.°
Secondary and Consumer Use
The principal end use of all commercial asbestos paper products is to
provide good insulation of minimum thickness against fire, heat, and
corrosion. General insulating paper is currently the major subclass of
commercial asbestos paper products. General insulating paper can be
subdivided into four types:^
• Commercial Grades: A medium length fiber paper with a minimum 95
percent fiber content. Available in 49, 59, 78, 156, and 312
kg/100 ra2 weights; in widths of 46, 91, and 352 cm; in 11, 23, and
45 kg 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 Hli-P-1784.
• Nonburn Paper: A medium length fiber paper with high fiber
content. Available in a weight of 20 kg/100 m2, 91 cm wide, in 23
or 45 kg rolls. Suitable for continuous service at temperatures of
3168C.
• Long Fiber Paper: Made with a high-grade, long asbestos fiber;
minimum fiber content of 98 percent in 2.7 kg and heavier papers.
For use as a thermal insulation, gasketing, and base sheet for
saturating.
• Doah Iex Asbestos Paper: Completely inorganic; will not burn, char,
or smoke. Has high wet strength. Available.in a weight of
49 kg/100 m2, 91 cm wide, in 23 or 45 kg rolls. Developed for use
as a neon sign pattern paper. Also used as liner for foundry
funnels and pouring gates. Temperature limit of 427°C or 649°C
where some embrittLenient and loss of strength is not critical.
39
-------
A Large portion of the general insulating paper produced is sold to
secondary fabricators and/or distributors who sell to their customers. 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. Some of the end uses are described below:^
• Thermal insulation in annealing furnaces,
• Trough lining for smelting process,
• Refractory lining,
• Expansion joints between brick layers of furnace,
• Backing insulation, and
• 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
glas,/ceramic industry, commercial paper is used for kiln insulation, linings,
and is a separator for hot and cold flat glass sheets. In a laminated form,
commercial asbestos paper is used to fireproof steel decks. Commercial paper
is also used in electrical insulation applications such as dielectric and
thermal protection of transformers for fluorescent tubes and housings for
mercery vapor lamps.^
Installation of the paper typically involves cutting it to size at the
site and then laying, nailing, and/or gluing it in place. The life span of
the paper depends on how it is used. No general estimate can be made because
of the multitude of its various uses. Asbestos insulating paper is usually
ripped out when removed, being crumpled up and thrown away.
Muffler paper is used by the automotive industry primarily in the
construction of catalytic converters for engine exhaust emission control
systems. The paper is applied as a wrap between the inner and outer skins of
the i onverter or muffler for two reasons; first, it maintains the high
temperatures required for pollution control within the converter reaction
chamber, and secondly, 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.**
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.^
40
-------
Environmental Release
Asbestos insulating paper has a tendency to crumple, crease, or tear
during preinstallation handling and installation. These actions, including
cutting during installation, can result in asbestos fiber release. Laboratory
tests simulating these handling activities have been performed on two types of
asbestos paper and one type of asbestos tape.8 Table 8 presents the results
of these tests that were conducted in a nonventilated glove box chamber.
During the testing of the 25 percent asbestos household paper for fiber
release due to cutting, a small amount of visible material was released into
the sampling chamber air space. Upon tearing, the edges of the paper appeared
to be friable; further, the paper could be separated into layers. This latter
occurrence results from manufacturing methods that allow for the buildup of
layers which adhere to each other upon drying, forming the finished paper
product. During product tearing, fibrous material was observed being released
into the chamber air space. Material released accumulated on the base of the
glove box after the paper was crumpled.
The commercial paper tested was composed of 75 percent asbestos, 10
percent cellulose, 5 percent opaques, 1 percent glass, and trace amounts of
clay, binder, and carbonate. The paper became quite friable while cutting
with scissors. During tearing and crumpling, pieces of the paper were
released, falling to the base of the glove box or becoming airborne.
The asbestos-containing paper tape tested was 7.6 cm (ca. 3 inches) wide
and was similar to a brand previously tested by a California TV station.^
The tape consisted of 20 percent asbestos, 60 percent cellulose, 5 percent
opaques, 5 to 10 percent glass, 5 to 10 percent carbonates, and trace amounts
of binder, clay, and gypsum. The release of fibrous material was also
observed from this product during cutting, tearing, and crumpling activities.
The tape was very friable during handling, am' the material released appeared
smaller in size than that released from the other products tested.
The study8 presenting these test results reports that NIOSH fiber
concentrations (phase contrast analysis) are 10 to 20 percent of the fiber
levels determined by SEM analysis. The reason for the difference is the
capability of SEM analysis to identify fibers as small as 0.5 urn in length and
0.05 um in width. The authors also conclude that the physical conditions the
experiments were performed under do not allow one to predict fiber release
levels during actual use. The researchers do insinuate, however, that
asbestos fiber release would be likely.
As shown in Table 8, the household roll paper and commercial paper
handling activities resulted in the lowest fiber release levels. The asbestos
paper tape revealed the greatest fiber release during routine handling. All
three products are believed to be readily available to consumers. With
respect to potential human exposure, discretion should be employed when
interpreting these test results. The experimental chamber in which the tests
were performed limited normal ventilation that would have a dilution effect on
fiber concentrations.
41
-------
TABLE 8. ASBESTOS FIBER RELEASE FROM SIMULATED ASBESTOS PAPER
HANDLING ACTIVITIES8
Material
25% Asbestos
household paper roll''
25% Asbestos
household paper roll1'
25% Asbestos
household paper roll*'
25% Asbestos
household paper roll*'
75% asbestos
commercial paper6
75% Asbestos
commercial paper6
20% Asbestos
paper tape*
Operation
Cutting
Tearing and
cutting
Replicate
of No. 1
Tearing
Cutting
Tearing and
crumpling
Cutting,
tearing and
crumpling
Test8
No.
1
2
3
4
5
• 6
7
Optical
microscopy
analysis"
(f/cm3)
2.2
4.8
2.0
2.3
Not analyzed
7.3
49.0
SEM
analysis0
(f/cn.3)
13.8
27.6
22.3
8.9
Not analyzed
58.9
262.0
aAll tests of 10-mi.nute duration, with the sampling pumps set at "6", (2.2
1pm).
^Fibers counted were *5 urn in length and had a length to width aspect ratio
equal to or greater than 3 to 1.
CSEM - Scanning Electron Microscopy. All asbestos fibers observed were
counted.
dPaper roll supplied by Grant Wilson.
eCommercial paper manufactured by Johns-Manville.
fPaper tape supplied by Grant Wilson.
42
-------
As indicated above, a California TV station sponsored an asbestos paper
product testing program to determine fiber release during product use.'-"
Fiber counts of 18 and 24 f/cra^ were measured, respectively, during the
cutting, rubbing, rolling and tearing of 70 to 80 percent asbestos tape and
shelf paper. Results were obtained by polarized light microscopy. Testing
was conducted inside a 30 x 43 x 43 cm glove box. The high levels recorded
are likely attributed to fiber accumulation in the confined air space of such
a sampling chamber.
Once installed, minimal asbestos fiber release is expected from the paper
products tested. Only during removal of the paper, or an accidental tear, is
it likely that the paper would release asbestos fibers. Fiber levels during
such incidents, occurring under actual conditions, are expected to be lower
than those reported. Additionally, the amount of material released would be
reduced if the paper was wetted before being removed.
ELECTRICAL INSULATION
Product Manufacturing and Composition
Asbestos electrical insulating paper is manufactured on conventional
paper machines. It is produced in various thicknesses and sizes in the form
of sheets, tapes, rolls, and tubes. The insulating paper's composition varies
with intended application, but generally contains asbestos fibers and
cellulose bound by latex polymers."
Electrical insulating paper production accounts for approximately 0.4
percent of the asbestos used in manufacturing asbestos paper products, or
about 360 metric tons in 1980.1 Because of developing substitute products
and employee concern about working with asbestos, a declining market is
forecasted for this product.
Secondary and Consumer Use
Finished electrical insulating paper may be used directly' or be
converted, by lamination, for other uses. Electrical insulating paper is used
in industrial, commercial, and residential applications. Industrially, it is
used in situations where electrical equipment is subjected to high
temperatures. Commercial use includes insulation in such items as stoves,
toasters (limited), and other appliances. Laminated insulating paper is used
for low-voltage household applications.^ On a larger scale, sheet laminate
is used for making telephone switchboards and television circuit boards.
Similar to other asbestos-containing paper products, the useful life span
of electrical insulating paper is related to its end use. Industrial use may
result in a short life span, less than 1 year, while laminated insulating
paper may be expected to last for several years.
43
-------
Environmental Release
Actions taken upon electrical insulating paper during fabrication and
product installation include punch pressing, shearing, cutting, winding, at
-------
TABLE 9. AIRBORNE ASBESTOS CONCENTRATIONS RESULTING FROM ASBESTOS
ELECTRICAL INSULATING PAPER AND BOARD MANUFACTURE AND
INSTALLATION17
Activity performed
Sterling magna ply
package operator
Paper machine rewind
Measured
fiber
concen-
tration
(f/cm3)
<0.016
<0.004
Date
of
tests
1980
1980
Duration of
activity
(min)
43
178
Analytical
method
Phase contrast
P!iase contrast
<0.005
<0.008
1980
1980
141
90
operator, 0.008 cm
thick paper
Paper machine rewind <0.006 1980
operator, 0.04 cm
thick paper
Millboard cutter operator
0.08 cm thick paper
Winding operator,
0.03 cm thick paper
Slitting operator, <0.008 1980
0.03 cm thick paper
Winding operator, <0.008 1980
0.008 cm thick paper
Slitting operator, 0.031 1980
0.008 cm thick paper
Electrical insulating 0.097 NO
paper—punch press
operator (TV BORD)
Electrical insulating 0.064 ND
paper—shear operator
(TV BORD)
Electrical insulating 0.008 ND
paper—assembly dept.
operator (TV BORD)
112
90
90
90
298
153
165
Phase contrast
Pl.ase contrast
Phase contrast
Phase contrast
Phase contrast
Phase contrast
Phase contrast
Piase contrast
Phase contrast
(continued)
45
-------
TABLE 9 (continued)
Activity performed
NECO, shear machine
operator
NECO, winding area
operator
Highlander, band saw
operator
Highlander, slitter
operator
Coil cutter operator
Coil cutter operator
Acme paper cutter
Acme coil cutter
Acme conv. winding
Acme heavy liandwinding
Acme coil pulling
Acme compound pourer
Kesiuite band saw
operator
Square D saw operator
Measured
fiber
concen-
tration
(f/cm3)
0.033
0.033
12. 3a
0.53'
0.094
0.015
<0.008
<0.013
<0.008
<0.006
<0.008
<0.012
0.034
0.062
Date
of
tests
1978
1978
1978
1978
ND
ND
1979
1979
1979
1979
1979
1979
ND
1980
Duration of
activity
(min)
120
180
30
42
118
94
91
53
87
108
'87
60
372
111
Analytical
method
Phase contrast
Phase contrast
Phase concrast
Phase contrast
Phase contrast
Phase contrast
Phase contrast
Phase contrast
Phase contrast
Phase concrast
Phase contrast
Phase contrast
Phase contrast
Phase contrast
ND - No Data
aReported as excessive.
46
-------
REFERENCES
1. Clifton, R. A., Asbestos. 1980 Minerals Yearbook. U.S. Bureau of Mines,
Washington, D.C. 1981.
2. Carton, R. J. 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.
PB-238-320, U.S. Environmental Protection Agency. February 1974.
3. Daly, A. P. et al. Technological Feasibility and Economic Impact of OS HA
Proposed Revision of the Asbestos Standard. Prepared by R. F. Weston for
Che Asbestos Information Association/North America, Washington, D.C.
March 29, 1976.
4. Cogley, D. et al. Life Cycles of Asbestos in Commercial and Industrial
Jse Including Estimates of Releases to Air, Water and Land. Draft Final
iteport, Prepared by GCA/Technology Division for the U.S. Environmental
Protection Agency, Office of Toxic Substances, Washington, D.C. November
1981.
5. Arthur D. Little Co., Characterization of the U.S. Asbestos Papers
Markets, Prepared for the Minister of Industry .md Commerce—Government
of Quebec. Final Draft Report to Sores Inc., Montreal, Report C-79231.
1976.
6. Meylan, W. M. et al. U.S. Asbestos Paper Industry and Substitutes for
Asbestos Paper and Asbestos Brake Linings. Draft Report, SRC No.
L1415-05, Syracuse Research Corporation. September 1979.
7. Blecher, L. GAF Corporation. Comments on Advance Notice of Proposed
Rulemaking on Commercial and Industrial Use of Asbestos Fibers. EPA
Docket No. OTS-61005. February 1980.
8. Roy, N. et al. Asbestos Product Test Results. Draft Final Report,
Prepared for the U.S. Environmental Protection Agency, Office of
Pesticides and Toxic Substances by GCA/Technology Division. February
L980.
9. Meylan, W. M. et al. Chemical Market Input/Output Analysis of Selected
Chemical Substances to Assess Sources of Environmental Contamination,
Task III—Asbestos. Report Prepared for U.S. Environmental Protection
Agency, EPA-560/6-78-005. August 1978.
47
-------
10. Chapman, J. H. et al. Asbestos Dust Technology Feasibility Assessment
and Economic Impact Analysis of the Proposed Federal Occupational
Standard: Part 1. U.S. Department of Labor, OSHA, NTIS No.
RTI/1370/02-01-F. September 1978.
11. Krusell, N. and D. Cogley. Asbestos Substitutes Performance Analysis.
Final Report, Prepared by GCA/Technology Division for the U.S.
Environmental Protection Agency, Office of Pesticides and Toxic
Substances, Washington, D.C. May 1981.
12. Roy, N. et al. Substitute Performance Analysis for Asbestos Paper
Products and Brake Linings. Prepared by GCA/Technology Division for the
U.S. Environmental Protection Agency, Office of Toxic Substances,
Washington, D.C. Draft Task Report. September 1979.
13. Cogley, D. et al. The Experimental Determination of Asbestos Fiber Size
Distribution During Simulated Product Use. Prepared by GCA/Technology
Division for the U.S. Environmental Protection Agency, Office of Toxic
Substances, Washington, D.C. 1981.
14. Lewis, B. G. Asbestos in Cooling Tower W.tter. Argonne National
Laboratory, Argonne, IL. NTIS No. ANL/ES-63. December 1977.
15. Gaudichet, A. et al. Asbestos Fibers in Wines: Relation to Filtration
Process. J. Tox., Environmental Health, 4:853-860, 1978.
16. \sbestos Paper Product Testing Results. Unilab Research, Berkeley,
California. Testing performed for Channel 7, KGO TV, San Francisco, CA.
November/December 1979.
17. A/ardly, F. L. , President, Quin-T Corporation, Electrical Insulations.
Written correspondence to Mr. Richard Guimond, U.S. Environmental
Protection Agency, Office of Toxic Substances, Washington, D.C.
October 30, 1980.
-------
SECTION 4
FRICTION MATERIAL
INTRODUCTION
Friction materials represent a broad classification of products that
include automobile brakes, both disc and drum (brake linings), truck brakes,
fan and transmission clutches, torque limiters and other devices used in the
automotive, truck, bus, heavy vehicle, aircraft and other industries to stop,
slow or control moving mechanical parts• These materials may contain anywhere
from zero (0) to 60 percent asbestos by composition depending upon the nature
of the heat build up generated and required for control of the mechanical
device involved.^
In 1980, an estimated 43,700 metric tons of asbestos, about 12 percent of
the United States fiber consumption, was used to manufacture friction
materials.2 Production volumes for each subcategory are not available, but
1981 value estimates show brake linings are the largest component at an
estimated 58.9 percent of total value of friction materials produced (see
Table 10).^ Disc brake pads (6.8 percent) and clutches (33 percent) make up
the majority of remaining value except for a small portion which is listed as
various other uses.3 Because of their near total representation (92
percent) of the friction products category, the following discussion pertains
solely to brake linings and clutch facings.
BRAKE LININGS
Product Manufacturing and Composition
Asbestos is used in the production of brake linings because of its
thermal stability, relatively high friction level and reinforcing properties.
Asbestos fiber composition ranges from 40 to 60 percent of the final product
by weight. All grades of chrysotile are used, but in 1980 grades S through 7
accounted for 94 percent of the 43,700 metric tons of asbestos consumed for
the production of friction materials.2 Because asbestos does not offer all
of the desired properties, other materials known as property modifiers and
binders are added. Depending on the requirement of the brake linings,
different types and amounts of modifiers are used. A list of the binders and
modifiers used in automobile brake linings are shown in Table 11.
49
-------
TABLE 10. VALUE OF ASBESTOS FRICTION MATERIAL SHIPMENTS
(IN MILLIONS OF 198L DOLLARS)3
Final product
Total product
shipments, including Percent
interplant transfers of
($) total
Brake linings
Woven, containing asbestos
yarn, tape or cloth
Molded, including all
nonwoven types
Disc brake pads
Clutch facings
Woven, containing asbestos
yarn, tape or cloth
Molded, including all
nonwoven types
Other
Total asbestos friction
material
27.8
308.4
38.8
54.2
132.2
9.8
571.2
4.9
54.0
6.8
9.5
23.1
1.7
100
^Projected from Meylan et al.-* using September 1981 Engineer-
ing and Mining Journal cost index factors.
50
-------
TABLE 11. PROPERTY MODIFIERS IN FRICTION MATERIALS3
Binders
Phenolic-type resins
Natural rubber
Buna N rubber
Nitrile rubber
Tire scrap
Pi tch
Cork
Gilsonite
Elastomers
Drying oils
Property modifiers
Graphite
Coke
Coal
Carbon black
Gilsonite
Friction dusts
Rottcnstonc (SiC>2)
Quartz (SiC<2)
Uollastonite (CaSiC^)
Brass chips
Zinc and compounds
Aluminum
Limestone (CaCO3>
Clays
Silicas
Barite (83804)
Lead and compounds
Antimony compounds
Calcium compound i
Copper and compounds
Barium hydroxide
Potassium dichromate
Magnesium carbonate
Iron oxide
Cryolite (Na6AlF3)
Fluorspar (CaF2>
Cardolite
Nickel
Sulfur
Molybdenum sulfide (MoS2)
Calcium fluoride
Use function
Lower friction coefficient and noise
Lower friction coefficient and noise
Lower friction coefficient and noise
Lower friction coefficient and noise
Lower friction coefficient and noise
Lower friction coefficient and noise
Remove decomposition deposits
Remove decomposition deposits
Remove decomposition deposits
Remove decomposition deposits
Remove decomposition deposits
Remove decomposition deposits
Improve wear resistance
Improve wear resistance
Improve wear resistance
Improve wear resistance
Lubricant Co prevent grabbing
Not available
Not available
Not available
Not available
Not available
Not available
Not available
Not available
Not available
Not available
Not available
Not available
Lubricant
Lubricant
-------
Most linings are produced from a wet-mix resin by extrusion or in rolling
processes. Initially, 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
surface ground to produce the desired dimensions.'*
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 (blocks) 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). These block linings are then finished by grinding.^
Asbestos demand for friction products forecasted to the year 2000 is
expected to grow at an annual rate of 2.2 percent.2 But based on an
estimated number of motor vehicles produced in the year 2000, and on the
assumption that the use of asbestos per vehicle will remain below present
standards, the demand could vary from 0 to 70,000 metric tons.
Secondary and Consumer Use
Brake linings are used primarily in the transportation industry but have
numerous uses wherever motion must be controlled. During operation the brake
lining engages with a metal rotor to form a sliding friction couple which
converts the kinetic energy of the rotating members into heat, absorbs the
heat, and dissipates it to the surroundings.-* The brake lining is
considered to be the expendable portion of the brake couple which over a long
period of time is converted to debris and gases.
With specific reference to consumer use, potential asbestos exposure
occurs during installation. Although most brake lining installations occur at
an assembly plant or service garage, millions of Americans perform their own
brake repairs. The following seven-step procedure (condensed) has been
developed to minimize exposure during commercial brake lining repair or
replacement:^
I. The work area should be set apart from others,
2. During dissembling, all parts should be set on the floor and cleaned
by vacuum,
3. Precaution should be taken during machining of the lining,
4. Cleaning equipment should be cleaned with care,
52
-------
5. All floor cleaning should be done with a vacuum,
6. Clean work cloches or leave them at work, and
7. Proper hygiene practices will help minimize exposure!
In addition, all asbestos-containing waste material should be properly
containerized to prevent exposure during handling and ultimate disposal.
Environmental Release
During use, brake lining surfaces are suspected to be subjected to
temperatures in excess of 800°C (1472°F), which would cause chrysotile
asbestos to transform to forsterite or to an amorphous magnesium silicate
phase." However, because the heat distribution is not uniform across the
lining surface, braking may liberate partially altered or even unaltered
chryaotile fibers. Abrasion and macroshear are other physical forces that
also contribute to the physical breakdown of the lining. '«8
Upon review of the literature, it is not absolutely clear whether fibrous
asbestos is or is not released during vehicle braking. Lynch (1968)9 has
suggested, similar to the discussion above, that the crystal structure of the
asbestos mineral fiber is degraded by heat released during braking, causing
the chemical conversion to olivine or forsterite. Findings published by Holt
and Young (1973), 10 however, conclude that fibers collected from the
atmosphere showed little evidence of loss of crystallinity. This Latter
summation was further documented by Alste e£ a±. (1976)^ who concluded that
the major effect of braking appears to be in separating bunches of fibers and
reducing their average length but not in altering their crystal structure.
Sampling conducted by Alste £t al. revealed an estimated average asbestos
concentration of 5 x 10^ fibers/nr in the vicinity of a heavily traveled
freeway
Elevated levels of asbestos were found in a study by Bruckman and
Rubino12 in which airborne asbestos concentrations were monitored at three
Connecticut toll plazas. Asbestos concentrations were found to vary between 3
ng/m3 (ca. 60 f/m3) and 41 ng/m3 (ca. 820 f/m3).* A nearby large
industrial asbestos user was suspected of influencing the highest measured
concentration. Although no direct correlation was made between vehicular
traffic and the asbestos concentration it was concluded that the decomposition
of brake linings is a significant source of airborne asbestos fibers. With
respect to fiber size distribution, Rohl et al. (1977)° reported for 10
brake dusts sampled in New York City that 80 percent of the chrysotile is in
free fibril form and is shorter than 0.4 am in length. Over 57 percent
repoitedly had lengths of about 0.2 urn. Analysis was performed by
tranbmission electron microscopy at 42,000x magnification.
*Assumed that 1 ng/m3 equals 20 f/m3.
53
-------
TABLE 12. SUMMARY OF PUBLISHED DATA - ASBESTOS EMISSIONS FROM BRAKE LINING USE
13,14
Publication
Lynch, 19689
Hjccn. 1970-*
Method us.'J to
on O.S pjie size membrane
A Jual cloud was £eneiated
collect
filters.
by using compressed
Met.iod us ad
to determine
asbestos content
of emission
Electron micrographs
Not seated
collecced by means ot a hand pump located in
center o £ ciu s t c 1 oud .
Asbestos
particle sice Asbestos content of
Not discussed zin;> a -Jibe brslcc
c-**t.Ttls noaMtcd on a J^nu'-^neLer. Air Ld'nplcs
or I*CTC oel>tie coLt»;ctea ooun wi.td of diic
Not stated
Neutron activation
Transmission electron
oiLroscupy
Mot discussed
Mot discussed
TcsC results and
procedures
prLcluded a size
distribution
1.61 and less
—442
—0.021
j.i- J. „_ ,-
.'jvV-o i c ... l97j/L;>
S3i~;'K's. w* £ ^i ^> _t(.c.' by ou*.utiug 3 ^LauJjrJ
Ar.-nt.4in c ir uidtr typical driving conditund
ir Ui. rjic, "itcm^aii. Hjre .ibu&ivi. cnnaitiuns,
:i.k
-------
TABLE 12 (continued)
Method used
to determine
asbestos content
Publication Method used to collect of emission
ig
collected froo naintenance shops 10 the New
York City arta. Transaisaion electron
microscopy* selected
area electron dtf-
tron uicroprobe
analyses
^,,.e cc dl., IS7611 Si iples hero taken trom fresh .inJ worn brak« Electron aicroscopy
Asbestos
particle size
distribution
BOX of fibers
were shorter
than 0.& ytn
Length
Hajority were
Linear dimension
2-1 St. avei«ge of 3-61
Consistent with, but lower Chan,
Mo percent figure given, however,
conclusion was that najor effect
of braking appears to be in
is 15 o.isicdlly j reprint of tnc Koal et Jl..
7o *:^J> with :l e inclus^oi oi oraKO wear
»c iJnplcs oucained iron Eurapc anJ Australia.
separating bunches of fibers and
but not in altering cheir crystal
structure
The acan weight percentage ranged
from 1.4Z in Australia Co 2.51 in
France
-------
In addition to those just cited, a number of researchers have discussed
the concern of asbestos fiber release from the handling and use of brake
liningsi Table 12 summarizes the published data. Meylan et al. (1978)3
present a detailed treatise of the literature relating to asbestos fiber
release from brake lining use and handle, one which we believe the reader
should review if he or she requires information beyond that presented in this
report.
The Jacko and DuCharme study1^ states that approximately 33.6 million
kilograms of asbestos in friction material wears away annually. Their
findings show that only about 0.2 percent of the debris is not converted to
some other nonasbestiform substance, thus total annual asbestos is estimated
at 71,759 kilograms. Of this amount 85.6 percent or 61,426 kilograms were
estimated to drop out on the ground, 11.2 percent or 8,037 kilograms were
estimated to be retained within the brake or clutch housing, and only 3.2
percent or 2,296 kilograms were believed to become airborne.
Asbestos fiber release during the removal, repair and/or replacement of
worn brakes has also been monitored.'^ The results presented in Table 13
indicate that the OSHA 2 f/cnr TWA asbestos concentration standard can be
exceeded during brake cleaning operations, particularly when compressed air
blowing is used to remove dust from the drums and back plates. It is
important to note that the data were obtained in 1976 and that the institution
of improved work practices that lower fiber release levels has occurred. Some
of these work practices are discussed below.
TABLE 13. ASBESTOS FIBER3 CONCENTRATIONS RECORDED DURING
AUTOMOBILE AND TRUCK BRAKE SERVICING19
Fiber concentration
Operation
Distance
(m)
Number (fiber
samples Mean
s/cmj)
Range
Auto - Blowing dust out of 0.9-1.5 4 16.0 6.6-29.8
brake drums with 1.5-3.0 3 3.3 2.0-4.2
compressed air 3.0-6.1 2 2.6 0.4-4.8
Truck - Renewing used 0.9-1.5 10 3.8 1.7-7.0
linings by grinding
Truck - Beveling new linings 0.9-1.5 5 37.3 23.7-72.0
a?'ibers 5-1000 pm in length, counted by optical microscopy.
56
-------
Alternative cleaning methods to air blowing have been found to reduce
asbestos exposure.20 Table 14 presents a comparison of asbestos fiber
concentrations recorded for various types of brake drum cleaning methods.
TABLE 14. ASBESTOS FIBER CONCENTRATIONS ASSO-
CIATED WITH EIGHT TYPES OF BRAKE
DRUM CLEANING METHODS20
1. Airblowing 43.8 fibers/cm3 x min
2. Dry brushing 15.0 fibers/cm3 x min
3. AMMCO detergent 2.9 fibers/cm3 x min
washer and vacuum
4. Nilfisk dry vacuum 2.2 fibers/cm3 x min
5. Sears dry vacuum 0.8 fibers/cm3 x min
6. Sears wet vacuum 0.6 fibers/cm3 x min
Bag-emptying exposure
7. Nilfisk empty (dry) 0.3 fibers/cm3 x min
8. Sears empty (wet) 0.0 fibers/era3 x min
Workers may also be exposed to asbestos fibers during brake lining
refacing and rebuilding even though raw asbestos fibers are not handled.
Asbestos exposure levels measured at three such fabricating plants are
presented in Table 15 by processing step.
CLUTCH FACINGS'
Product Manufacturing and Composition
Asbestos is used in clutch facings for the same reasons as in brake
linings; thermal stability, relatively high friction level, and reinforcing
properties. The asbestos level in the product ranges from 40 to 60 percent of
which most is grades 5 through 7 chrysotile. Other materials used at various
times are wire reinforcers, rubber friction compounds, and various solvents.
These materials are combined to produce clutches by five different
methods; dry-mix, wet-mix, molded, paper, and woven textiles. Dry-mix and
wet-mix processes are similar to those described for brake linings. Molded
clutch facings are produced by combining materials in a mixer, conveying this
through a two-roller mill which compresses the mixture. The resultant
sheeting is then cut to size, dried, finished, inspected and packaged. Paper
clutch facings are punched from rolls of asbestos paper as described under
transmission paper in the previous section on asbestos paper products. Woven
clutch facings are manufactured from high strength asbestos textile fabric
that may be reinforced with wire. The fabric is saturated 'witn resins and
autoclaved prior to being wound into yarn and finally into a clutch facing.
Production levels for clutch facings are not reported but a breakdown of
the value of asbestos bearing friction materials, including clutch facings, is
given in Table 10.
57
-------
TAIiLK 15. ASBESTOS EXPOSURE LEVELS IN REBUILDING BRAKE AND
CLUTCH ASSEMBLIES21
Fibers/cm-* TWA
Receiviag and Bonding and Cutting and Inspection and
Facility cleaning riveting grinding packaging
A
Mean 1.1 0.6 1.1 0.9
Range 0.4 - 4.8 0.2 - 1.4 0.8 - 1.6 0.8 - 1.1
Number of 15 20 - 6 4
samples
B
Mean 4.0 2.7 5.0
Range 1.0 - 7.6 l.l - 5.8 1.5 - 9.3
Number of 5 6 6
samples
C
Mean 1.3 0.8
Range 1.2 - 1.3 - 1.5 - 9.3
Number of 2 6
samples
58
-------
Secondary and Consumer Use
CLutch facings are used mainly in Che transportation industry, although
they can be used for any application that has the potential of switching
gears. In an automotive application, the engaging of a clutch transfers the
kinetic energy of a rotating crankshaft to the transmission and wheels. Any
slippage results in the generation of heat, which is absorbed and eventually
dissipated to the atmosphere by the clutch.-* The clutch friction material
is considered to be expendable.
The wear of a clutch depends on the amount of slippage since the clutch
is basically a static friction couple which momentarily slides during gear
shifts. Once the clutch cannot hold a continuous couple, it must be replaced.
Environmental Release
Specific asbestos fiber concentration monitoring studies have not been
reported for clutch repair or replacement work. Fiber release levels,
however, are expected to be lower than those reported for brake lining repair
and replacement because the clutch facings are normally covered with a
lubricating transmission fluid. The fluid would effectively suppress the
release of asbestos fibers during handling.
59
-------
REFERENCES
1. Drislane, E. W. Written Response to U.S. Environmental Protection
Agency's ANPRM on Asbestos. Submitted in behalf of the Friction
Materials Standards Institute, Inc. to be included in the Office of Toxic
Substances' Docket No. OTS-61005.
2. Clifton, R. A., Asbestos, A Chapter from Mineral Facts and Problems.
1980 Edition. Washington, D.C., U.S. Bureau of Mines. 1981.
3. Meylan, W. M., et al. Chemical Market Input/Output Analysis of Selected
Chemical Substances to Assess Sources of Environmental Contamination,
Task III - Asbestos. Prepared for U.S. Environmental Protection Agency,
EPA-560/6-78-005. August 1978.
4. Krusell, N., and D. Cogley. Asbestos Substitute Performance Analysis.
Prepared by GCA/Technology Division for the U.S. Environmental Protection
Agency, Office of Toxic Substances, Washington, D.C. May 1981.
5. FMSI Issues Review of Asbestos Handling Procedure for Brake and Clutch
Repairs. Brake and Front End. July 1977. pp. 22-23.
6. Rohl, A. N., et al. Asbestos Content of Dust Encountered in Brake
Maintenance and Repair. Proceedings of Royal Society Medical J. Vol.
70. January 1977.
7. Burnell, J. T., 1957. Wear. Vol. 1, p. 119.
8. Mizutani, Y., H. Ohara, and K. Nakajima. 1973. Wear, Vol. 23, p. 387.
9. Lynch, J. R. Brake Lining Decomposition Products. Journal Air Pollution
Control Association. 18(12 ) :82A-826. December 1968.
10. Holt, P. F., and D. K. Young. 1973. Asbestos Fibers in the Atmosphere
of Towns. Atmospheric Environment, 7:481-483; 669-670.
11. Alste, J., D. Watson, and J. Bagg. 1976. Airborne Asbestos in the
Vicinity of a Freeway. Atmospheric Environment. Vol. 10. pp. 583-589.
60
-------
12. Bruckraan, L, and R. A. Rubino. Monitored Asbestos Concentrations in
Connecticut, J Air Pollution Control Association. 28(12):1221-1226.
December 1978.
13. Jacko, M. G., and R. T. DuCharme. Brake Emission: Emission Measurements
from Brake and Clutch Linings from Selected Mobile Sources. U.S. NTIS
PB-222-372. 1973.
14. Jacko, M. G., R. T. DuCharme, and J. H. Somers. How Much Asbestos do
Vehicles Emit? Automotive Engineering, 81:38-40. 1973.
15. Hatch, D. Possible Alternatives to Asbestos as a Friction Material. Ann
Occup Hyg. 13:25-29. 1970.
16. Hickish, D. E., and K. L. Knight. Exposure to Asbestos During Brake
Maintenance. Ann Occup Hyg. 13:17-21. 1970.
17. Bush, H. D., D. M. Rowson, and S. E. Warren. The Application of Neutron
Activation Analysis to the Measurement of the Wear of a Friction
Material. Wear, 20:211-225. 1972.
18. Anderson, A. E., R. L. Geacer, R. C. McCune, and J. W. Sprys. Asbestos
Emissions from Brake Dynamometer Tests, Paper 730549 presented at SAE
Automotive Engineering Meeting, Detroit, Michigan. 1973.
19. Rohl, A. N., et al. Asbestos Exposure During Brake Lining Maintenance
and Repair. Environmental Research. 12:110-128. 1976.
20. Lemmons, T. Method of Cleaning Debris from Brake Drums Study of Asbestos
• Exposures. Environmental Protection Agency, Research Triangle Park,
North Carolina. 1980.
21. Unpublished NIOSH data presented at American Industrial Hygiene
Conference, New Orleans, Louisiana. May 5, 1977.
61
-------
SECTION 5
FLOORING PRODUCTS
INTRODUCTION
The manufacturing of floor products is Che second largest industrial use
of asbestos, consuming 76,539 metric tons in 1980.* Floor products can be
divided into two separate subgroupings, flooring felts and floor tiles. The
production of flooring felts consumed 40,509 metric tons of asbestos while the
rest (36,080 metric tons) is used for the production of tile flooring.
Flooring felts have already been discussed in Section 3 under Paper Products.
The tile flooring industry produces two major product lines:
vinyl-asbestos floor tile and asphalt-asbestos floor tile. Vinyl-asbestos
floor tile consumes up to 95 percent of the asbestos used by the floor tile
industry.^ Both types of asbestos tile utilize grades 5 and 7 chrysotile
fibers to obtain the desired properties; strength, dimensional stability, and
resistance to the cold.-* Production methods for both are similar except for
the high processing temperature required to flux and process the vinyl
copolymer.
VINYL-ASBESTOS FLOOR TILES
Product Manufacturing and Composition
As stated above, within this category vinyl-asbestos floor tile
production consumes 95 percent of the asbestos fibers, or an estimated 34,275
metric tons in 1980. Specific ingredient formulations vary with manufacturer
and the type of tile. Reported asbestos contents range from 5 to 30 percent
by weight or up to 635 grams of asbestos per square meter (0.13 pounds per
square foot) of tile. •* Polyvinyl chloride (PVC) resin serves as the
binder and constitutes from 15 to 25 percent by weight of the tile.^
Fillers, such as limestone and color pigments, make up the remainder of the
ingredients.
Ingredients .are usually dry mixed in a Banbury mixer, then are dispersed
through the vinyl mass along with any required liquids. The temperature of
the Lath is raised to L49°C (300°F), and the mixture is fed to the mill where
it if shaped to the desired size, decorated, and cooled. After cooling, the
tile is waxed, cut to size, inspected, and packaged. Tiles are usually
produced in sizes 23 x 23 cm (9 x 9 in.) or 30 x 30 cm (12 x 12 in.) with
thicknesses varying from 0.08 to 0.24 cm (1/32 to 3/32 in.).4
62
-------
After a period of a marked decrease in asbestos consumption during the
70's, the market share of all forms of vinyl flooring is now believed to be
well established and is not expected to change in the foresee.ible future. The
20-year forecast predicts a range for annual asbestos consumption at 110,000
to 220,000 metric tons, with the probable amount being 170,000 metric
tons.l»6 A large percentage of tile production, an estimated 40 to 60
percent, is intended as flooring replacement.2
Secondary and Consumer Use
Vinyl-asbestos tile flooring is used for protective and decorative
covering of floors in industrial, commercial, and residential applications.
New floor covering may be installed on concrete, prepared wood floors, or over
old cile floors if they are in relatively good shape. In some cases, an old
floor may require repairing rough spots or gouges using a patching material or
may actually require a totally new surface whereby fiberboard or masonite
underlayment is laid on top of the old floor.' For industrial and
commercial installations, the tiles are commonly affixed to the underlayment
using a tacky adhesive. Most tile sold for consumer application is normally
coated on the back with a layer of pressure-sensitive adhesive,® which by
itself minimizes potential fiber release.
During installation, some cutting with scissors or shears may be involved
to fit the flooring to the size of the room. Other than following
manulacturer's recommended installation procedures, no control measures are
used during the cutting and installing of the floor covering. Manufacturers
of rtsilient floor coverings that contain asbestos fibers have made it their
policy to warn their wholesalers and distributors against sanding old floor
coverings.'' Similar warning messages are packaged with floor coverings sold
directly to "do-it-yourself" homeowners.^
Envir inmental Release
During floor tile manufacturing, asbestos fibers are mixed with other
ingredients such that the fibers become locked in the product matrix. From
this point on, the fibers remain securely bound within the vinyl resin
compound. In addition, the wear surface of floor coverings is usually coated
with an abrasive-resistant urethane finish which increases the isolation of
the asbestos from the external environment.^ The following presents a
summary of available monitoring data and release estimates reported in the
literature for vinyl-asbestos tile installation, use, maintenance, and
removal. The fiber concentrations reported were determined by che NIOSH
method; i.e., fibers as long or longer than 5 urn with as aspect ratio of -J to
1 or greater were counted by phase contrast analysis using optical light
microscopy.
Installation of vinyl-asbestos floor tiles results in minimal fiber
release. As stated above, the asbestos fibers are locked-in, therefore, any
release is expected to occur only if the asbestos fibers were sheared away
from the encapsulating material. Monitoring of fiber release during
63
-------
installation of vinyl-asbestos floor tile has been performed for the Resilient
Floor Covering Institute (RFCI) by SRI International.9'10 The results of
the SRI study are presented in Table 16. As shown in the table, asbestos
fiber levels associated with tile installation are well below the OSHA TWA
limit of 2 fibers/cm3.
The service life of a vinyl-asbestos floor is estimated to be between 10
and 30 years.-* During this time, various forces act upon the flooring which
may result in the release of asbestos fibers. Monitoring of fiber release
during use and maintenance has also been performed by SRI for RFCI.9>10 ^s
shown in Table 16, no fibers were detected from mopping and buffing
vinyl-asbestos floor tile in an office building's copy center and snack shop.
Asbestos fiber release from everyday wear and cleaning of vinyl-asbestos
flooring has also been estimated by researchers based on calculated material
wear.2 The calculated releases ranged from 0.008 to 0.08 f/cm3.2 Four
assumptions were made before these fiber release levels ware calculated:
• Each square meter of floor tile contains 635 grams of asbestos,
• The average service life of the floor is 20 years,
• Approximately 10 percent of the flooring is worn away during the
service life by use and cleaning, and
• About 1 percent of the worn-away floor becomes airborne.2
The greatest potential for asbestos fiber release during floor tile use
occurs during removal. At the end of the floor's lifetime, usually when the
surtace design is worn away, the flooring may be ripped up or covered with a
new surface underLayment. If the flooring is ripped up, pieces of tile may
remain affixed to the floor which have to be scraped up or sanded down to
level off the subflooring. Various monitoring studies have been performed
during Eloor.tile removal.'«^,11,12 SRI's results^ilO are presented in
Table 16. The results of another study11 revealed a fiber concentration
range of 0.02 to 0.10 f/cm^ during vinyl-asbestos floor tile removal. The
fourth study,12 performed under a laboratory setting, reports asbestos fiber
release during sanding to remove old asbestos rloor tile. The results showed
that sanding can cause the release of 1.2 to 1.3 fibers/cm^ into the worker
environment.12 The experiment was performed in a 3 x 3.7 x 2.1 meter
(10 x 12 x7 ft) walk-in chamber. Room ventilation involved four air changes
per hour. A belt sander with coarse paper was used to remove a section of old
vinyl-asbestos floor tile.
ASPHALT-ASBESTOS FLOOR TILES
Asphalt-asbestos floor tiles represent only S percent* of the asbestos
floor tile industry.2 The differences between asphalt-asbestos and
vinyl-asbestos floor tiles are only minor; therefore, the discussion above on
vinyl-asbestos floor tile applies directly to asphalt-asbestos floor tile use.
-------
TABLE 16. ASBESTOS FIBER RELEASE FROM VINYL-ASBESTOS FLOOR TILE INSTALLATION,
USE, MAINTENANCE, AND REMOVAL9•L0
Sice description
Age of tile
(years)
Operation
TWA fiber count range
(f/cra3)
Residential home 6
Residential home New
Residential home New
Residential home New
Office building copy center 5
Office building snack shop 5
Office building copy center 5
Office building snack shop 5
Office building copy center 5
Office building snack shop 5
Residential home NR
Residential home 6
Old tile preparation
for new installation
Installation
Installation
Installation
In-use
In-use
Maintenance - mopping
Maintenance - mopping
Maintenance - buffing
Maintenance - buffing
Removal
Removal3
0
0.0046 to 0.0092
0.008 to 0.027
0.016 to 0.032
0
0
0
0
0
0
0.006 to 0.015
0.12 to 0.38
aKcnioval deviated from recommended procedures that include removal without sanding, use of
a flat-bladed wall scraper instead of equipment that would unduly shatter the tile, and not
breaking the tile by hand before placing in a disposal bag.
NK = Not reported.
-------
REFERENCES
1. Clifton, R. A., Asbestos. A Chapter from Mineral Facts and Problems,
1980 Edition. U.S. Bureau of Mines, Washington, D.C. 1981.
2. 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 1981.
3. Cogley, D. et al. Life Cycle of Asbestos in Commercial and Industrial
Use Including Estimates of Releases to Air, Water, and Land. Draft final
report prepared by GCA/Technology Division for the U.S. Environmental
Protection Agency, Office of Toxic Substances, Washington, D.C., January
1981.
4. Chapman, J. H. et al. Asbestos Dust Technological Feasibility Assessment
and Economic Impact Analysis of the Proposed Federal Occupational
Standard: Part 1. U.S. Department of Labor, OSHA. September 1978.
5. Daly, A. R. et al. Technological Feasibility and Economic Impact of OSHA
Proposed Revision of Asbestos Standard (Construction Excluded). Prepared
by R. F. Weston for the Asbestos Information Association/North America.
March 26, 1976.
6. Clifton, R. A., Asbestos: Mineral Commodity Profiles. U.S. Bureau of
Mines, Washington, D.C. 1979.
7. The Resilient Floor Covering Institute. Comments on the Advance Notice
of Proposed Rulemaking on the Commercial and Industrial Use of Asbestos
Fibers. Washington, D.C. February 18, 1980.
8. Blecher, L. GAF Corporation. Comments on Advance Notice of Proposed
Rulemaking on Commercial and Industrial Use of Asbestos Fibers. EPA
Docket No. OTS-61005, February 1980.
9. SRI International. Monitoring for Airborne Asbestos Fibers: Vinyl
Asbestos Floor Tile. Prepared for Resilient Floor Covering Institute.
December 1979. SRI Project 7988.
10. SRI International. Comparison Testing Monitoring for Airborne Asbestos
Fibers: Vinyl Asbestos Floor Tile. Prepared for Resilient Floor
Covering Institute. December 1979. SRI Project 7988.
66
-------
II. Roy, N. et al. Asbestos Produce Test Results. Draft Final Report,
Prepared by GCA/Technology Division for the U.S. Environmental Protection
Agency, Office of Toxic Substances, Washington, D.C. February 1980.
12. Murphy, R. L. et al. Floor Tile Installation as a Source of Asbestos
Exposure. American Review of Respiratory Disease, Vol. 104. 1971.
67
-------
SECTION 6
GASKETS AND PACKING
INTRODUCTION
This category, gaskets and packing, is ranked sixth in annual consumption
of asbestos fibers, consuming 12,300 metric tons of asbestos or 3 percent of
the total U.S. consumption in 1980.1 Asbestos is used for gaskets and
packing because of its resilience, strength, chemical inertness and heat
resistant properties.2 A variety of other materials may be used in the
manufacturing process to give a gasket specific use qualities. With respect
to packing material, it is typically made of asbestos yarn saturated with a
grease-based lubricant.
Gaskets and packing are used to prevent leakages; gaskets for static
applications and packing for dynamic applications. Gaskets are needed to
obtain tight nonleaking connections for piping and other joints such as the
covers and opening on all types of industrial and commercial equipment.
Packing is used as a type of bearing for revolving or moving parts, preventing
leakage of the contained fluid along the bearing surface.
GASKETS
Product Manufacturing and Composition
Gaskets are made from compressed sheet or beater-add asbestos paper.
Compressed sheet gaskets will be discussed in this section. Beater-add
gaskets have been previously discussed under the paper products category
(Section 3). Compressed sheet gaskets are formed from a plastic mixture
consisting of asbestos fibers, an elastomeric binder, and a solvent. The
process consists of mixing the ingredients, rolling them out to a specific
thickness, drying, cutting to size, and packaging. Packages of compressed
sheet are normally shipped to a secondary manufacturer who cuts out the
gaskets as needed, usually by die-cutting.
The amount of asbestos used in producing gaskets is approximately 66
percent^ of the total amount consumed by this category or 8120 metric tons
of asbestos based on I960 data.'- Commercial grade gasket sheet contains 75
to 80 percent asbestos; specialty grades may contain as much as 100 percent
asbebtos. For the specialty gaskets both chrysotile and crocidolite asbestos
fibers are used, whereas for the others chrysotile is predominantly used.
68
-------
The consumption of asbestos in the production of gaskets and packing has
decreased only slightly, 4 percent, since 1976. Between 1974 and 1976 it had
decreased 25 percent because of newly developed products, the use of
substitute materials, and recognized health hazards. Use of asbestos is
expected to continue near current levels due to the advantages of the fiber
compared to substitutes and because the hazardous fiber form of the material
is not employed.3 The 20-year forecast indicates that asbestos consumption
will range from 0 to 30,000 metric tons, with a probable value somewhere
around 25,000 metric tons annually.^
Secondary and Consumer Use
Asbestos gaskets are used to obtain a tight nonleaking connection between
piping and other joints. It is used on all types of industrial and commercial
equipment with specialty items such as impregnated millboard being used in
small motors for things like snowblowers and lawnmowers. The primary product,
the asbestos sheets, are usually sold to secondary fabricators, who size cut,
package, and sell the gaskets wholesale or retail.
Installation is simple once the gasket is cut to size; it consists of
setting the gasket in place between two rigid surfaces and sealing the joints
with pressure. In service, the faces are completely isolated from the outside
environment. After installation, the gasket's life span is dependent on the
seve 'ity of use and maintenance practices. It has been estimated-* that 25
percent of gasket materials have less than a 1-year lifespan, 60 percent are
used for maintenance and long-time replacement, and 15 percent for new
installation.
Environmental Release
Following manufacture, asbestos fibers are considered to be locked in the
gasket sheeting material. Consequently, only minimal fiber release is
expected during secondary fabrication and product end use. Studies have been
conducted to monitor asbestos fiber concentrations associated with various
asbestos sheet gasket handling, fabricating, installation, and removal
activities.^>5.« These studies were performed under actual conditions.
Asbestos fiber concentrations recorded during these activities are presented
in Table 17. Except in two cases, hand punching and machine punching, fiber
levels were all below the current OS HA 8-hour TWA standard of 2 f/cm->. It
is noted that the relatively high fiber levels recorded for hand and machine
punching occurred when no controls were emplo/ed. When control measures were
applied to these two operations, resultant fioer concentrations were reduced
to levels well below the 2 f/cnH standard.
Another study7 reported fiber levels during cutting and packaging of
asbestos gasket sheeting at 0.1 to 0.5 f/cra^. Fiber release during use is
expected to be less than that measured during cutting because at no time is
the asbestos-containing material acted upon with a force that would cause the
release of fibers from the product matrix.
69
-------
TABLE 17. ASBESTOS FIBER CONCENTRATIONS ASSOCIATED WITH VARIOUS COMPRESSED
ASBESTOS SHEET CASKET HANDLING ACTIVITIES*'5.6
Study Activity perioraeJ
Measured
fiber
concentrations
Dace
of
tests
Duration of
activity/
sample tin*
(•in)
Analytical Mthod
Coonencs
A Punch press operation
blear press operation
press
Pic'Un operation
H/J;jjlic bean press
rijnJ pl»klu£ and pj^kaginj
0.04 to 0.67
0.17
0.23 CO 0.81
0.04 to 0.08
0.10 to 0.31
0.42 to 0.60
0.11 co 0.34
O.OS to 0.29
0.01 to 0.15
0.02 to 0.05
0.06 to 0.20
1980
1940
1980
1980
1980
1980
1980
1980
1980
1980
1980
80 to 211 Fibers were counted by
phase contrast with
PLM verification
188 Fibers were counted by
phase contract with
PLM verification
SO to 76 Fibers were counted by
phase contrast with
PlH verification
Monitoring performed at a
suijor gasket fabricator
located in Wisconsin
Monitoring performed at a
major gasket fabricator
locates in Wisconsin
Monitoring perfomed at •
•ajar gasket fabricator
located in Wisconsin
100 to 192 Fibers were counted by Monitoring perforaed at a
phase contrast with najar gasket faDncator
PLM verification located in Wisconsin
93 to 206 Fibers were counted by Monitoring performed at a
phase contrast with sujor gasket fabricator
PLM verification located in Wisconsin
77 to 141 Fibers werj counted by Monitoring performed at a
phase contract with najor gasket fabricator
PL1 verification located in Wisioisin
91 to 216 Fibers were counted by Monitoring performed at a
phase contrast with eujjor gasket fabricator
PLM verification. located in Uiaconsin
S2 to 256 Fiberc were counted by Monitoring performed at a
pnace contrast with major Basket fabricator
PLM verification located in Wisconsin
63 to 238 Phase contrast Monitoring performed at an
asbeatos~using gasket
operation in Wisconsin
61 to 178 Phase contrast Monitoring perfumed at an
asbestos-using gasket,
operation in Wisconsin
45 to 176 Phase contrast Monitoring perfumed at an
asbestoa-using gaaket
operation in Uiaconaio
(continued)
-------
TABLE 17 (continued)
Study
Activity performed
Measured Duration of
cioer Date activity/
concent rations of staple Ciae
(f/co3) testa (nin)
Analytical mathod
Contents
Platen press picking operator 0.09 to 0.12 1980 67 to UO Pha
punch press o,»ar.iEjr
Storage for use
Hand punching
rland pun*.hinj
.•>:*• 31-cal punching
Machine punciing
Machine punching
H.iiid shaping
0.12 1980 124 Phi
eipt and issue <0.0l to 0.05 1978 60 Co 132 Phase contract
<0.01 to 0.12 1978 97 Co 122 Phase contrast
3.00 1978 NR Pha
<0.05 to 0.15 1978 28 .a 31 Phase contrast
<0.05
5.0
1978
L978
30
NR
Pha
Phase contrast
<0.03 to 0.7 1978 20 to 30 Phase contrast
<0.05 to 0.06 1978 23 to 31 Phase contrast
«0.03 to 0.3 1978 7 co 31 Phase contrast
Monitoring performed at an
asbestos-using gasket
operation in Wisconsin
Monitoring performed at an
asbestos-using jascet
operation in Wisconsin
Houstkeeping* performed.
monitoring conducted under
actual work conditions
No control,1* monitoring
conducted under actual work
conditions
conducted under actual work
conditions
Housekeeping performed.
monitoring conducted under
actual war* conditions
No control, monitoring
conducted under actual
work conditions
No control, oomcoring
conducted under actual
work conditions
Housekeeping performed,
monitoring conducted under
actual work conditions
Housekeeping and veoti-
lation,c nonitonng
conducted unJer actual
conditions
No control, monitoring
conducted under actual
work conditions
(continued)
-------
TABLE 17 (continued)
Study
Activity performed
Measured
fiber
concentrations
(f/cm3)
Date
of
testa
Duration o{
activity/
aample time
(Bin)
Analytical method
Comments
Ma:hine shearing
Machine shearing
?iachine nibbling
0.5 to 1.3 1878
Phase contrast
0.05 to 0.15 1978 31 to 38 Phase contract
<0.08 to 0.46 1978
Phase contrast
0.08 to 0.8 1978 24 to 31 Phase contract
Installation of flange gasket <0.03 1978 30 Phase contract
a-iJ concurrent
J. i jn C=oiler hea
Clean-up following renoval
oy hand scraping
0.02 to 0.3 1978 21 to 93 Phase contrast
<0.05 1978 33 to 37 Phase contrast
*. ,\i I a-.d "scraping »0.0b to 0.3V 1978 1} to 28 Phase contrast
and wire brushing <0.03 to 0.18 1978 25 to 13 Phase contract
No control, oonitoring
conducted under actual
work conditions
Housekeeping performed,
nonitonnf conducted under
actual work condition!
No control, monitoring
conducted under actual
work conditions
Housekeeping perforaed,
aonitocing conducted under
actual work condition*
No control, monitoring
conducted under actual
work conditions
Housekeepinr performed,
monitoring cotdu^ted under
actual work conditions
Ho control, monitoring
conducted under actual
work conditions
Mo control, monitoring
conducted under actual
work conditions
Housekeeping performed.
monitoring conducted under
actual work conditions
^.Ijua .^1*1.01 is - hi£h ef
v.n.t.. material placed
vacuum cleaners were used to clean areas (area kept clean and free of debris accumulation).
°
-------
With respecc co removal, gaskets are generally treated so that they will
release from the equipment face when it is necessary to replace them.8
Should any portion stick to the support surface, it may be removed using a
scraping tool. As shown in Table 17, gasket removal by hand scraping or wire
brushing resulted in fiber releases ranging from 0.03 to 0.39 f/cm^. The
high level of 0.39 f/cm^, however, was recorded when no control measures
were taken. Wetting down the gasket remnants with oil or water prior to
removal with an abrasive tool should substantially reduce the potential for
fiber release.
Westinghouse has reported that asbestos-containing gaskets are used in
residential air conditioners.^ The gasket material is used in a
hermetically sealed unit which is normally not repairable and thus totally
discarded after use. Gasketing materials containing asbestos fibers are also
used in larger air conditioning units that are not hermetically sealed, but
because of their size and cost, they are replaced by skilled personnel and
therefore should not be a source of significant release.^
PACKING
Product Manufacturing and Composition
In 1980 approximately 4180 metric tons of asbestos were consumed in the
production of packing.^ The most common type of packing is made by
impregnating asbestos-containing yarn with a lubricant.*0 The impregnated
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 be coated again with more lubricant. The packing is then pressed into
desired shapes for use or sold to a secondary fabricator who forms it to
customer specifications before lie sells it.^
Secondary and Consumer Use
Asbestos packings are used in dynamic situations to prevent fluid
leakage. They form a bearing for revolving or moving parts in stationary
supporting members that prevent leakage of the contained fluid along the
bearing surface. Lubricated asbestos packings are employed in a variety of
industrial, commercial, and residential applications, as well as in motor
vehicles. Dry asbestos packing is used to seal furnace doors, rotary kilns
and high-temperature refractory equipment.
Installation of the packing is easy once the packing is molded to form.
Once in place the packing is enclosed by the supporting members of the unit.
The life span of packing material, after installation, has been estimated to
be less than 1 year for 90 percent the packing applications, while the rest
wear much more rapidly after installation.-'
Environmental Release
Release of asbestos fibers to the atmosphere is considered to be minimal
or nonexistent during packing handling and use. During installation the
fibers are completely saturated with lubricants which inhibit the release of
73
-------
asbestos fibers. When the packing is in use, it is intermittently or
continually coated with lubricants. Asbestos fibers released during wear
should be captured by the lubricants or carried away in the process fluid
system. Removal of packing should cause minimal fiber release since the free
fibers are wetted and captured by the lubricant or process fluid.
>
Johns-Manville Corporation has conducted a study^ to determine
airborne fiber concentrations associated with the installation and removal of
asbestos- containing mechanical packing. The simulated installation activity,
performed in an open building, involved unrolling the packing material,
wrapping it around the metal shaft of a mechanical pump, cutting the material
flattening it with a hammer, and finally pushing it into the pump. Fiber
levels recorded during these activities ranged from <0.1 to 0.1 f/cnr.
Similar fiber levels were recorded during removal of the packing from the pum)
after the pump had been run for a while. Although it was not reported, phase
contrast analysis employing optical light microscopy was assumed to be used to
determine fiber concentrations.
74
-------
REFERENCES
1. Clifton, R. A., Asbestos, A Chapter from Mineral Facts and Problems.
1980 Edition. Washington, D.C. U.S. Bureau of Mines. 1981.
'2. Cogley, D., et al. Life Cycle of Asbestos in Commercial and Industrial
Use Including Estimates of Releases to Air, Water, and Land. Draft Final
Report. Prepared by GCA/Technology Division for the U.S. Environmental
Protection Agency, Office of Toxic Substances, Washington, D.C. January
1981.
3. Meylan, W. M., et al. Chemical Market Input/Output Analysis of Selected
Chemical Substances to Assess Sources of Environmental Contamination,
Task III - Asbestos. Report prepa'red for U.S. Environmental Protection
Agency. EPA-560/6-78-005. August 1978.
4. Liukonen, L. R. et al. Asbestos Exposure From Gasket Operations. Report
prepared by Industrial Hygiene Branch, Naval Regional Medical Center,
Bremerton, Washington. May 1978.
5. Hager Laboratories, Inc. Report on Service Number 3910, For
Johns-ManvilLe Corp., August 21, 1980. Published in Health and Safety
Facts: Mechanical Packings and Casketing Materials Containing Asbestos
Fibers, Johns-Manville Corp., Denver, Colorado.
6. Johns-Manville Corporation: Health, Safety, and Environment Department.
Industrial Hygiene Survey Conducted July 1980 in Wisconsin. Results
published in Health and Safety Facts: Mechanical Packings and Gasket ing
Materials Containing Asbestos Fiber, Johns-Manville Corp., Denver,
Colorado.
7. Chapman, J. H., et al. Asbestos Dust Technological Feasibility
Assessment and Economic Impact Analysis or the Proposed Federal
Occupational Standard: Part 1. U.S. Department of Labor, OSHA.
September 1978.
8. Bleclier, L., GAF Corporation, Comments on Advance Notice of Proposed
Rulemaking on Commercial and Industrial Use of Asbestos Fibers. February
7, 1980. U.S. EPA Docket No. OTS 61005.
75
-------
9. Gormley, J. F. Submittal of Westinghouse Electric Corporation to U.S.
Environmental Protection Agency's Office of Toxic Substances for
Inclusion into Docket No. OTS 61005: Commercial and Industrial Use of
Asbestos Fibers; Advance Notice of Proposed Rulemaking.
:
10. Kruaell, N., and D. Cogley. Asbestos Substitute Performance Analysis.
Draft Final Report prepared by GCA/Technology Division for U.S.
Environmental Protection Agency, Office of Toxic Substances, Washington,
D.C. May 1981.
11. Johns-Manville Corporation: Health, Safety, and Environment Department.
Industrial Hygiene Survey of Simulated Field Installation of
Asbestos-Containing Packings. Results of study published in Health and
Safety Facts: Mechanical Packings and Gasketing Materials Containing .
Asbestos Fiber, Johns-Manville Corporation, Denver, Colorado.
76
-------
SECTION 7
COATINGS AND SEALANTS
INTRODUCTION
Asbestos-containing coatings and sealants can be divided into two basic
categories; those which are of a tar or asphalt base and those which have a
water soluble latex or gypsum base. Asphalt or tar-based sealants include
products such as: roofing tar, flashing material, automobile undercoat ings,
waterproofing and floor mastics.* These products are put into final use by
construction contractors, small businesses (such as for auto undercoating and
private roofers) and often the "do-it-yourself" homeowner. The products are
applied by brush, spray gun, roller, or trowel depending upon ita consistency
and intended use. Asbestos fibers contained within coatings and sealants are
bound in the asphalt or tar matrix. The fibers have an affinity for the
petroleum base materials and thus are totally wetted by the asphalt or tar in
the mixture. Consequently, no fibrous asbestos dust is expected to be
released during the use of these products.2
Water soluble asbestos-containing coatings and sealants include products
such as speckling compounds, drywall patching and taping compounds, and
textured paints. These products are used by building contractors both large
and small as well as do-it-yourself homeowners. The latex products often come
in premixed containers whereas the gypsum based materials come dry and must be
mixed by the user. Significant fiber release can occur from mixing of dry
materials, sanding, and cleanup.
ASPHALT/TAR-BASED SEALANTS
Product Manufacturing and Composition
Asphalt or tar-based sealants which contain asbestos fibers as a filler
and strengthener are composed of 5 to 10 percent asbestos, 50 percent volatile
solvents, and various amounts of tars, rust proofing chemicals, pigmerts, heat
reflecting metallic paints, and other fillers such as cork, emulsifiers, and
resins. The solvents are added to reduce product viscosity and thus
facilitate application of the material. The asbestos fibers used are nearly
all (98 percent) grade 7 chrysotile, which become totally wetted in Che
mixture.*
77
-------
Sealants are produced in batches under a controlled production cycle.
Initially, the fibers are fluffed prior to being charged to a batch blending
tank where they are mixed with asphalt or tar and other additives as required
for an even dispersion. After blending, the liquid product is pumped to
dispersing operations, and finally shipped out to market.
The batch sizes produced will vary from noveral hundred gallons for small
manufacturers with one production line to several thousand gallons for larger
manufacturers who are able to have a wide product mix and several production
lines.^ The batch sizes also vary with company size, type of product,
method of containerization, type of production equipment, and size of order.
Sealant products are shipped out ready for distribution and use.
Consequently, no secondary producers are involved.
The Bureau of Mines reports that 1980 usage of asbestos fibers for
coatings and sealants production was approximately 10,900 metric tons.^ The
expected trend for asbestos consumption is not to decline or increase, but to
remain stable.
Secondary and Consumer Use
The asphalt and tar-based sealants and coatings which contain asbestos
are used by various tradesmen and contractors as well as the individual
homeowner. Sealants sold for consumer use generally come packaged in S gallon
or smaller size containers. As a roofing product the material is applied as a
thick tar commercially spread by large brushes and trowels. It is most often
applied to large, level top buildings, although due to its adhesive,
lonrunning characteristics (which in part is attributed to the presence of the
isbestos fibers), it can be spread on nonhorizontal surfaces as well.
-lashing materials are also applied by trowel. As a thicker material, it is
primarily applied to small areas such as joints ana seams in the roofing.
Wacer proofing and rust proofing sealants are applied by brush or spray,
and may need to be applied in several coats to achieve the desired
protection.I
Environmental Release
In general, asphalt and tar-based sealants which contain asbestos are
considered safe for use with respect to asbestos exposure. The U.S. EPA,
under the authority of the National Emission Standards for Hazardous Air
Pollutants (NESHAPs)-*, has banned the use of all spray-applied
asbestos-containing coatings and sealants except those that are made from a
petroleum-based compound. The level of ambient fiber release during the use
of these products is not considered harmful. In response to EPA's notice of
proposed rulemaking concerning the ban of spray-applied asbestos-containing
coating materials various studies^ were conducted to demonstrate the minimal
heal'h effects associated with the use of such petroleum-based produces.
78
-------
Asbestos fiber concentrations recorded during the spray application of
different types of asbestos-containing petroleum-based coatings are presented
in Table 18. As shown, across a wide range of products and product
applications, worker exposure to asbestos fibers were well below the 2 f/cm^
TWA OSHA standard. These findings support EPA13 decision not to ban the use
of such products.
WATER SOLUBLE LATEX OR GYPSUM-BASED SEALANTS*
Product Manufacturing and Composition
There are two principal types of joint compounds. One uses a latex or
water soluble glue as a binder and sets by evaporation of the water. The
other uses dehydrated gypsum as the binder (and principal dry ingredient) and
sets by chemical reaction as the gypsum takes up waters of hydrat ion. The
first type is mainly limestone with lesser amounts of mica and 3 to 5 percent
asbestos. This type is used in about 80 percent of the market, and is mostly
sold in the ready-mixed, wet form. The gypsum-based material, with roughly 20
percent of the market, also usually contains asbestos and must naturally be
sold dry and wetted just before use. The worker mixes the compound with water
in the field. Wet-mix products are manufactured and packaged in a can for
ready use.3
Manufacture of both these products involves the usual handling of raw
asbestos fibers where bags are stored, moved, split, dumped and fluffed.
After dry blending, the latex-based products are wet mixed, binding the fibers
in the matrix. The dry mixed gypsum-based product, which is not wetted during
manufacture, maintains the potential for fiber release throughout the
manufacturing process, as well as during packaging, distribution, and consumer
use. ^
Secondary and Consumer Use
The use of these products and thus their manufacture is declining
primarily' because of the high potential for exposure to hazardous levels of
asbestos during manufacturing and end use. A major impact on product use has
resulted from the Consumer Product Safety Commission's (CPSC) ban of consumer
patching compounds containing respirable free form asbestos.^ Some
asbestos-containing products are still used by commercial dry wallers but the
health safety factors will most likely drive these users towards alternative
materials as well.
Certain decorative textured paints have also contained asbestos in the
past, but manufactures say they have ceased making these products with
asbestos, using other fibrous materials instead."'*
*Joint compounds, patching plaster, spackle, drywall taping and finishing
compounds.
79
-------
TABLE 18. ASBESTOS FIBER CONCENTRATIONS ASSOCIATED WITH THE SPRAY APPLICATION OF
ASBESTOS-CONTAINING PETROLEUM-BASED COATING PRODUCTS6
§
Asbestos-contain.:!*; Activity
product porfom^J
Spray-applied asphaleic
rDof cjati.ig
Cutojck. asphalt Spraying
\sp -4« L -emulsion Spraying
Bull t-ap roofing Icar-of f
T* ir-jf l and
rt.pl i*. j (apray)
•;o-' application
(spray)
'es.n cjatin^s Snip coating by
spray application
Dry Jock coating
b/ ^pr«i/ application
Co it i i; pi,.-
Fihei-£la4fi pipe
'_"« (M. iJitl coating)
Ship coating odlow
appl icacion)
4il.lLlli* .lUlUlUg
Duration of
Measured fiber activity/
concentration Date of sampling cine Analytical
(f/ca3) tests (rain) method
0.003 to 0.1S 1974 342 Co 432 Phas« contrast'
(assumed)
0.01 co 0.3 1974,1976 HR Phase contrast
(aaauned)
0.1 to 0.4 1974 Nl Phase contrast
(assumed)
(assumed)
0.2 1974 A to 33 Phase contrast
(assumed)
0.0 to 0.2 1974 11 to 38 Phase contrast
(assumed)
O.L 1974 37 Phase contrast
(assumed)
0.1 to 0.4 1974 14 co 23 Phase contrast
(assumed)
U.O to 0.4 1974 23 to 65 Phase contrast
(assumed)
0.0 LU 0.06 1974,197~j S to 16 Phase contrast
(aasuned)
Consents
Percent weight of asbestos as sprayed
ranged from S.8 to 7.7, after curing
9.7 co 12. tf
Percent weight of asbestos aa sprayed
was 2. B. after curing S.I
Monitoring performed in Indiana
Monitoring perfumed in Pennsylvania
and Indiana
Monitoring perfumed in Wisconsin,
Colorado, and Indiana
Operator spraying outside and under a
ship with asbestos-containing epoxy
resin. Percent asbestos as sprayed
l.S
Operator spraying Joe* with an
•Mixture. One percent asbcbtos as
sprayeJ
Operator spraying interior of 7.6, IS
and 30 cm diameter pipe with an
asbestos-containing (1 percent) epoxy
Operators monitored were involved ta
ru.ming automatic spray machine and
wiping ta«ndrcL. A 1.4 percent asoes^os
applied
0.7 percent asbestos applied
asbestos or vinyl-acrylic latex
containing 0.6 percent aabescoe
applied
(continued)
-------
TABLE 18 (continued)
CO
Pe^surcd fiber
Resin coatings Painting building 0.03 to 0.06
donLiniied) interior fcomxjrc lal )
Uall and roof spraying 0.0 to 0.2
Kj,«£ spraying 0.0
BojC MFC - spraying 0.0 to 0.6
Sawing pipe cojted 0.04 lo 0.1
Si 1-1. ng FIP tin1-* 0.3 to 0.6
ail plp*.
Sand blasting nigh 0.2 to 0.3
perfoijiance ax'enor
C JJC lllj
Date of
testi
1977
1974
1974
1972.1974.197S
1973
1971,
1977
1978
Duration of
activity/
aanpling time
Uin)
23
12 to IS
U to 28
4 to 55
19 to 49
5 to 25
1 co 16
S to 27
4ijl/llcaL
net hod
Phiie contrast
(assumed)
Phace contrast
(asauaed)
Phase contrast
(aasumcd)
Phase contrast
(assumed)
Phase contrast
(assumed]
(assumed)
Vnake contrast
(assumed)
Phase contrast
Cement s
Vinyl-acrylic lacex containing 0.6
percent ssbestoc applied
panel
Operator spraying 0.7 percent
asbestos acrylic latex
perat r sa g r n r i ergla
l.S asbestos
O^ratot nundsan-iing panel iurtaces
Operators sandblasted 12 meter diao
by 7.b met:r high steel tank spray
coated in 1^7) wich a 2.1 percent
11
ss
eter
5 .
; or ioi£.«r with a ldr.£tn Co vidch aspect racio of 3 or greater were counted by phace contrast analyflia uaing optical Light aiccoscopy.
-------
The following describes a common product end use for dry wall spacklers
who apply asbestos-containing patching compounds in a finishing operation.^
In the construction of a commercial building, wallboards are fixed to metal
studs with screws, while in residential houses the gypsum wallboards are
nailed into the wooden studs.10 The resulting joints, as well as screw and
nail indentations, are finished by taping and spackling.
The dry joint compound powder is normally contained in paper bags. The
bag is slit open with a knife and the powder dumped into a container. Water
is then added according to the manufacturer's directions and the compound
mixed by means of a portable electric drill equipped with a mud or paint mixe •
bit. Some joint compound is sold as a paste (referred to as "preraix") and-
only a small amount of water is required. The prepared mixture in its
putt/-Iike form after wetting is referred to as mud. The time spent mixing in
a working day is short. It usually takes 5 to 10 minutes to mix a batch and
in most instances one to three batches are required daily.^
The joint compound (mud) is placed on the bottom side of a paper tape and
is applied to cover the joints between the gypsum boards and allowed to dry.
Subsequently, this compound is also applied on the front side of the tape and
to screw and nail indentations. A major portion (65 to 70 percent) of the
working day is spent in this operation.^
The joints and indentations are sanded between each application of mud,
with the major amount of sanding being carried out after the final coat.
Three to four coats of mud are usually applied. Sanding operations normally
involve either hand sanding or pole sanding. Hand sanding is carried out with
a hand-held, abrasive paper, covered sanding block. In pole sanding, the
sanding block is at the end of long pole. Generally speaking, most of the
sanding is carried out by pole sanding. It is estimated that 25 to 30 percent
of total time is spent In this operation.^
The debris and the dust accumulated on the floor resulting from the
mixing, application and sanding operations is generally cleaned up by dry
sweeping. In many instances, especially in cases of commercial building and
large projects, this operation is carried out by general laborers. However,
it was generally found to be part of the work responsibilities of employees of
small companies working on residential construction projects.10
Environmental Release
The asbestos release potential of these products is relatively high. A
summary of airborne asbestos concentrations is given in Table 19. The table
breaks down exposure levels into the various steps of product use and
handling. Even though the CPSC has banned the use of these materials, a fair
amount may still be in circulation in the marketplace. Consequently, the
following discussion presents suggested recommendations to-minimize worker
contamination.
Verma and MiddLeton10 reached the following conclusions based on the
data thev recorded:
82
-------
TABLE 19. SUMMARY OF AIRBORNE ASBESTOS FIBER CONCENTRATIONS ENCOUNTERED IN THE DRYWALL
TAPING PROCESS10'11
Asbesto>-contai.niag Activity
oraJuct performed
n'jtdr »oia^l* Application
drywill coapound Mixing
(Study A) (dry pounder)
Mixing
hjno sanding
Pole sanding
Pole sanding
Sweep Lilg
00
jypsja-dJaed (0.9 to l.S a)
cryvall caopound
(Study &)
Pand sanding
(0.9 to 1.5 •>
tile Banding
(0.9 to 1.5 a)
Sweeping hose
O.O io 1})
Measured fiber
(f/cc3) tests
0.4 to 1.3 1978
9.0 to 12.4 1975 Co 1977
1.2 co 3.2 1978
2.1 CO 24.2 1975 CO 1977
1.2 to 10.1 1975 ca 1977
1.2 to 10.0 1978
4.0 to 2i.5 1975 to 1977
14.5 to 25. 4 1978
35.4 CO 59.0 1974
1.3 co 16.9 1974
1.2 co 19.3 1974
41.4 (unMi.) 1974
Duration of
activity/
sampling tiae
(oin)
39 co 65
10 ce 12
4 co S
10 Co 80
10 co 38
4 co 21
9 to 30
10 co 20
MS
NX
m
SR
Analytical
tathod
Phase contrast8
Phase contrasc
Phase contrasc
Phase contrasc
Phase contrast
Phase concrasc
Phase contrast
Phase concrssc
Phase concraac
Phase concrasc
Coameoca
Coasaercial operacion
*
Commercial operations
Residential setting
Commercial operation
Residential setting
Commercial operation
Commercial operation. Fiber range
reported la not less background
level a, which Cor the aaoe room
ranged fron 0.5 to 1" ' f/ca3
Connercial operation. Fiber range
reported ia not le*s background
levels, which Cor the sarae rooa
ranged fron 2.1 to 2.3
Commercial operation. Fiber range
reported ia not lea* background
levela. which for the saote raoa. ranged
from 3.S to 19.8
Due to heavy loading during sveepLQ&,
sampling occurred 15 minutea after
•weeping atopped. After 35 minute*.
the mcaaured fiber level was 26.4
f/co.3.
longer Ji th a lengtn co width aspect ratio of 3 or greater uere counted by Phase Contrast Analysis using optical microscopy.
-------
1. The Capers are occupational!/ exposed to potentially hazardous
asbestos dust concentrations in their work. The asbestos hazard can
be eliminated by the .use of asbestos free joint compound. Although
asbestos-free joint compound is available and most manufacturers are
actively working towards the reduction and/or elimination of
asbestos in their material, most of the taping compounds used still
contain asbestos. The use of an asbestos-free compound is the only
feasible method of total control of asbestos exposure and is
therefore strongly recommended. However, a person engaged in
mixing, sanding, and sweeping, of an asbestos-containing compound
should wear an approved protective respiratory device.
2. The use of a pre-mix compound is preferable over a dry powder joint
compound because it eliminates potential high exposure during
mixing. It is recommended that the amount of joint compound used
should be the minimum necessary to complete the job.
3. Sanding is the most hazardous operation of the taping process
because the concentrations of asbestos encountered are high and a
large portion of total time is spent in this operation. To reduce
the exposure potential, various control measures should be
considered, including the effective use of respirators and rotation
of workers.
4. The short-term hazard associated with sweeping and cleanup
operations could be reduced by employing an industrial type vacuum
cleaner. If a broom must be employed, a dust suppressant compound
should be used.
5. Tapers who work with asbestos-containing compounds should be
included in the medical surveillance program for asbestos workers.
Additional epidemiological studies of this group of workers are also
recommended. Furthermore, tapers should be familiarized with the
potential health hazards, especially the greatly elevati-d lung
cancer risks for asbestos workers who smoke.
6. The unnecessary exposure of tradesmen not directly involved in
taping, can be avoided by proper job scheduling and restricting
their entry to exposure areas. Contamination of the home
environment can be minimized by careful handling of workclothes and
good personal hygiene.
-------
REFERENCES
1. 'Jogley, D., et al. Life Cycle of Asbestos in Commercial and Industrial
Use Including Estimates of Releases to Air, Water, and Land. Prepared
for the U.S. Environmental Protection Agency, Office of Toxic Substances
by GCA/Technology Division, January 1981.
2. Meylan, W. M., et al. Chemical Market Input/Output Analysis of Selected
Chemical Substances to Assess Sources of Environmental Contamination:
Task III. Asbestos. Prepared for the U.S. Environmental Protection
Agency, Office of Toxic Substances, EPA-560/6-78-005. August 1978.
3. Daly, A.P., et al. Technological Feasibility and Economic Impact of OSHA
Proposed Revisions to the Asbestos Standard (Construction Excluded).
Prepared for the Asbestos Information Association/North America by R. F.
Weston Environmental Consultants. March 26, 1976.
4. Clifton, R. A., Asbestos, A Chapter from Mineral Facts and Problems.
1980 Edition. Prepared for the U.S. Department of the Interior, Bureau
of Mines. Preprint from Bulletin 671.
5. 40 CFR Part 61, National Emission Standards for Hazardous Aii
Pollutants. 38 FR 8820, April 6, 1973, as amended.
6. Testimony Prepared for A Public Hearing Before the California
Occupational Safety and Health Standards Board. November 8, 1978.
Source of testimony unknown. Information supplied to GCA by
Johns-Manville Corporation, Denver, Colorado.
7. Consumer Product Safety Commission, 16 CFR Part 1304 - Ban of Consumer
Patching Compounds Containing Respirable Free Form Asbestos - 42FR
63362. December 15, 1977. pp. 203-207.
8. Telecon. Charles Spector, Everseal Manufacturing Co., Inc., with David
Cook, GCA/Technology Division, January 17, 1980.
9. Telecom. Jack Fleming, Bondex International, with David Cook,
CCA/Technology Division, January 16, 1980.
10. Verma, D. K., and C. G. Middleton. Occupational Exposure to Asbestos in
the Drywall Taping Process. Presented in the Journal of American
Industrial Hygiene Association, Vol. 41, April 1980. pp. 264-265.
85
-------
11. Fischbein, A., et al. 1979. Drywall Construction and Asbestos
Exposure. J. American Industrial Hygiene Association. Vol. 40, pp.
402-407.
86
-------
SECTION 8
ASBESTOS-CEMENT SHEET
INTRODUCTION
Asbestos-cement (A/C) sheet, which is the only product in this category,
is used mainly in construction applications, such as roofing and sidings of
both industrial and residential buildings.'- Constituting approximately 2.2
percent (7,900 metric tons) of the 1980 U.S. market consumption for
asbestos-containing material, A/C sheet is categorized into four distinct
product lines:2
• flat sheets
• corrugated sheets
• siding shingles
• roofing shingles
Flat sheet has a variety of construction applications. Density
variations generally determine the product's end use. Ordinary or high
density sheets may be used for external cladding applications, while special,
low density panels, containing a larger portion of asbestos fibers, are
designed for use as infill panels for curtain wall systems, fire-resistant
partitions, ducting, fume hoods and doors.^ Other uses include laboratory
bench tops, electrical equipment mounting panels, components in vaults, ovens
and safes, and cooling tower fill sheets. Corrugated sheets are used
primarily in industrial and agricultural applications whereas roofing and
siding products are used in building construction. Other sheeting uses
include lining of waterways and canal bulkheads, and end paneling for cooling
towers.•*
PRODUCT MANUFACTURING AND COMPOSITION
A/C sheet products typically contain 30 to 40 percent asbestos, by
weight, with chrysotile grades 6 and 7 most commonly used.l»2 Primary
manufacturing of A/C sheet and shingles include dry, wet, or wet nechanical
processes. Wet processed A/C sheet production closely parallels A/C pipe
manufacturing; dry processing is used to make certain shingle type products.*
87
-------
Secondary processing of A/C sheet products is generally performed at
central fabricating shops. Material is cut and shaped into specific sizes for
sale to a distributor or the consuming public. Fabricating processes, which
include sawing, trimming, drilling, and grinding, are generally conducted
under controlled conditions.^
Today the use of A/C sheet is narrowing toward applications where its
special properties of durability and heat and chemical resistances are not
duplicated by other ste*! materials. Demand for asbestos use in the
construction industry is expected to remain at present levels; approximately
70 percent of all asbestos-containing material usage.^ However,
substitution is currently being actively investigated in many of the product
uses, particularly in asbestos-cement products where a variety of alternative
ceramic and new plastic materials are available.2 The most apparent
opportunities for market increases appear to be asbestos-cement products which
compete with lumber and other building products, many of which are increasing
rapidly in price.2 The extended forecasted growth rate for asbestos-cement
products is estimated to average 0.6 percent per year.2
SECONDARY AND CONSUMER USE
Almost all A/C sheet consumption is for a construction-related
application. Some field fabrication of A/C sheet products may be necessary,
specifically in shingle applications. Field fabrication of A/C sheet can
release some dust during fitting, cutting, drilling or grinding operations,
but it has been found that emission control devices, such as bags to collect
dust, are usually used in the field when such operations are performed.1
Hand tools (without controls) may also be used in the field, but che extent of
use is not accurately known. Flat asbestos sheets used in homes, barns, or
other more expensive construction, are usually installed with fasteners or
nails, requiring only minimal drilling, if any.1
Life expectancy of A/C sheet products vary with use. A/C roofing
shingles are thought to last 20 to 25 years, while laboratory table tops and
textured architectural construction lasts until the building of which they are
a part of is torn down.1
ENVIRONMENTAL RELEASE
Asbestos tiber release, and subsequent exposure to asbestos material, is
a function of material age and condition, mechanical forces applied, and the
degree of area ventilation. Generally, asbestos fibers are embedded firmly in
shingle tiles (or sheets) such that handling or installation (where hammering
is the mechanical force applied) are not major sources of asbestos fiber
exposure. Installation of A/C sheet material is generally performed outdoors
where direct exposure to asbestos fiber takes on a lesser magnitude3 due to
ambient air dilution. Removal of A/C sheet by building demolition, however,
constitutes a greater potential for asbestos fiber exposure.
88
-------
Published data on asbestos fiber release from both simulated tests and
actual field applications are available. Fiber release tests of Transite® ,
an A/C sheet product manufactured by Johns-Manvilie, were performed in a
nonventilated glove box chamber." Commonly used as an insulating panel in
wood stove installations, the A/C material was subjected to four test
activities routinely performed in construction applications. Asbestos fibers
in this product may be characterized by unsorted fibers and bundles embedded
in an irregular orientation in the cement matrix.& The test results appear
in Table 20.
TABLE 20. FIBERa RELEASE CONCENTRATIONS ASSOCIA-
TED WITH ASBESTOS-CEMENT SHEET PRODUCT
USE ACTIVITIES6
Operation
Drill
Score
Hammerc
Hamme rc
Saw
Time
(min)
1
4
1
4
1
Phase contrast
(E/cm3)
2.3
3.2
12.7
6.4
195.8
SEM^
(E/cm3)
2.3
1.1
16.5
10.2
258.8
aFibcrs as long as or Longer than 5 pin having a
length to width aspect ratio of 3 to 1 or greater
were counted by optical microscopy analysis.
bSEM - Scanning Electron Microscopy analysis.
cUnclear whether this operation simulated instal-
lation with nails (fasteners).
An epidemiological study conducted in West Germany has estimated
construction worker exposure to asbestos fine dusts. Worker activity
monitoring occurred at approximately 40 building sites where roofing and
siding work was being performed. Onsite tests of asbestos fiber release frjm
grinding operations performed on corrugated asbestos-cement sheets revealed
that near the breathing zone of the workers, fiber concentrations ranged from
0.6 to 41 t"/cm3 of length greater than 5 microns with a mean value of 20
f/cm^.7 Scanning electron microscopy analysis revealed that the mean
-------
values of fiber length ranged from 1 to 5 pm and fiber diameter from O.I to
0.4 urn. The ratio of fibers with a length greater than 5 urn to the total
number of free fibers ranged from 4 to 60 percent, with a median value of 25
percent. The authors state that on the average, grinding accounts for only 6
percent of the working time.? As such, the daily mean value reaches only
1.2 fibers/cm^. According to the study,-roofing operations involving the
grinding of corrugated asbestos-cement sheets are carried out up to 125 days
per year. The study goes on to explain that, based on a sampling of 61
roofeis, the frequency of handling corrugated sheets, shingles, and front
plate asbestos-cement building products, wnere the grinding machine is not
used, are 34, 30 and 25 days per year, respectively. It is noted that workers
may handle more than one type of asbestos-cement product on any given day.
Although it is beyond the scope of this study, researchers in Belgium
have ihown that asbestos-cement dust behaves more like cement dust (Portland
cemeni P300) than like pure asbestos fibers.& The results of their study
reveal that respirable asbestos-cement dust particles are physiochemically
different from respirable pure asbestos dust. Asbestos-cement products tested
(machining) were autoclaved sheeting, not autoclaved sheeting, and A/C pipe.
The authors do conclude, however, that the results obtained from their study
cannot be used to assess whether asbestos-cement dust is as hazardous to human
health as pure asbestos dust.
Continuing, a simulated product use demonstration^ conducted by Nilfisk
of America, a leading manufacturer of HEPA filtered industrial vacuum cleaners
for toxic materials, revealed that fiber releases can be minimized using power
tools equipped with dust control apparatus. Phase contrast microscopy
analysis of air samples taken during the drilling and cutting of
asbestos-cement board ranged from 0.04 to 0.15 f/cm-*. Sampling periods
ranged from 12 to 17 minutes using a power circular saw, drill and saber saw.
Oust capture was achieved using hooded cools that vented to a Nilfisk filtered
vacuum cleaner. No visible emissions were observed from the operation while
the vacuum cleaner was activated.
Another simulated A/C sheet monitoring study was performed by the
Johns-Manville Corporation.10 The results of J-M's tests using dust
controlled construction tools indicate little or no tliber release during the
drilling and sawing of 0.64 cm thick (0.25 in.) flat A/C sheet. Measured
fiber levels are presented in Table 21.
Table 22 shows the typical exposure levels occuring during primary and
secondary manufacturing of A/C sheet. Primary and secondary manufacturing
operations are generally controlled.
In summary, asbestos fibers embedded in the cement matrix will generally
remain so for the life of the product, with the exception of when mechjnical
forces are applied during handling. It has been estimated that 0.1 percent of
asbestos in root' products can become detached by weathering.^ Other
environmental releases include landfill disposal of manufacturing wastes or
old, worn-out product.
90
-------
TABLE 21. AIR MONITORING TEST3 RESULTS USING A CIRCULAR SAW AND DRILL
ON FLAT A/C SHEET10
Time Fiber concentration'3
Operation (min) Equipment (f/cm->)
Drilling holes 40 Drill with dust 0.1
(163 holes) pick-up shroud; operated
at full speed
Sawing 40 Circular saw with 0.0
(18.3 meters) dust pick-up shroud;
totally enclosed masonry
blade
aAll tests conducted in an open room.
^NIOSH's phase contrast analysis assumed, counting fibers 5 ym long or
longer with a length to width aspect ratio of 3 or greater.
TABLE 22. EXPOSURE TO AIRBORNE ASBESTOS FIBERS DURING A/C SHEET
MANUFACTURINGS
Asbestos concentrations
(Time-weighted average in fibers/ctr.^)3
Operations with highest levels
Most operations ——
Name of
Operation Typical Range Typical Range operation
Primary manufacturing 2.0 0.3-8.7 3.0 0.9-8.4 Dry mixing
Secondary manufacturing - 1.0-6.0 2.5 co 3.0 - Trimming,
sanding
aNIOSH's Phase Contrast Analysis performed counting fibers 5 urn long or
longer with a length to width aspect ratio of 3 or greater.
91
-------
REFERENCES
1. Cogley, D., et al. Life Cycle of Asbestos in Commercial and Industrial
Use Including Estimates of Releases to Air, Water, and Land. Draft
Final Report, prepared by GCA/Technology Division for the U.S.
Environmental Protection Agency, Office of Toxic Substances, Washington,
D.C. October 1979.
2. Clifton, R. A., Asbestos 1980. U.S. Department of the Interior, Bureau
of Mines. 1980.
3. Krusell, N., et al. Asbestos Substitute Performance Analysis. Final
Report, prepared by GCA/Technology Division for the U.S. Environmental
Protection Agency, Office of Toxic Substances, Washington, D.C. May 1980.
4. Chapman, J. H., et al. Asbestos Dust Technology Feasibility Assessment
and Economic Impact Analysis of the Proposed Federal Occupational
Standard. Part 1. U.S. Department of Labor, OSHA. September 1978.
NTIS No. RT1/1270/02-01-F.
5. Levine, R. J. (ed.). Asbestos: An Information Source. DREW Pub. No.
(NIH)79-1681. May 1978.
6. Cogley, D., et al. The Experimental Determination of Asbestos Fiber Size
Distribution During Simulated Product Use. Final Report prepared by
GCA/Technology Division for the U.S. Environmental Protection Agency,
Office of Toxic Substances, Washington, D.C. May 1981.
7. Rodelsperger, K., et al. Estimation of Exposure to Asbestos-Cement Dust
on Building Sites. Study supported by the Umwelfbundesant, Berlin,
Project No. 10401023/11, by the Commission of the European Community,
Project No. 298-78L ENVD, and by the Bau-Berufsgenqssenschaften,
Frankfurt.
8. Hasten, J., J. Helsen, and A. Deruyttere. 1980. Nature, Structure, and
Properties of Asbestos Cement Dust. British Journal of Industrial
Medicine. Vol. 37, pp. 33-41.
9. Intra-laboratory Memo, Argonne National Laboratory. Asbestos Fiber
Measurements During the Nilfisk Power and Vacuum Demonstration. August
JO, 1979. Memo received from Bruce Newman, Nilfisk of America, Inc.,
King of Prussia, Pa. December 7, 1981.
92
-------
10. Asbestos Information Association/North America, Recommended Work Practice
Procedures Cor Asbestos-Cement Sheet. Submittal to U.S. Environmental
Protection Agency, Office of Toxic Substances, in response to Commercial
and Industrial Use of Asbestos Fibers: Advance Notice of Proposed
RuLemaking. Docket Number OTS 61005.
11. MeyLan, W. M., et al. Chemical Market Input/Output Analysis of Selected
Chemical Substances to Assess Sources of Environmental Contamination:
Task III - Asbestos. Report prepared for U.S. Environmental Protection
Agency. EPA-560/6-78-005. August 1978.
93
-------
SECTION 9
TEXTILES
INTRODUCTION
Because asbestos fibers, after a minimal amount of conditioning, are
processable on conventional textile manufacturing equipment, they are
available in all conventional textile forms including: lap, roving, yarn,
cord, thread, cloth, tape, tubing, wick, rope and felt.'- Approximately
two-thirds of all manufactured asbestos-containing textiles are used as an
intermediate product to produce other materials such as friction products,
insulation, packings and gaskets.^ Long asbestos fibers which are processed
into various intermediate textile forms are generally worked into protective
clothing, insulating materials, filters or diaphragms.
TEXTILE MANUFACTURING AND COMPOSITION
Asbestos-containing textile products typically contain from 75 to 100
percent asbestos fiber. Small percentages of cotton, rayon and other natural
or synthetic fibers are blended with asbestos to improve spinnability and to
impart the desired serviceability to the end product.3. Approximately 1,900
metric tons of asbestos or about 0.5 percent of the total U.S. fiber
consumption went into textile manufacturing in 1980.^ Long, spinning grade
chrysotile fibers, grades 1, 2, and 3, are predominantly used.
Primary manufacturing of asbestos textile products include the
conventional process and the wet process. Most textiles are made by the
conventional process by either the dry or damp methods. Both methods are
identical except that during damp processing, yarn is moistened to reduce fiber
emissions. The conventional dry process produces a small volume of highly
specialized yarn without absorbing any water.'
The more newly developed wet process yields a product that tends to hold
asbestos fibers better than those produced by the conventional processes, thus
reducing workplace fiber levels. The yarn formed, however, tends to have poor
absorption and impregnation characteristics.^ Raybestos-Manhattan Inc. has
been involved in Che development of this new wet process.^ Their process,
referred to as the Novatex® method, mixes asbestos fibers with hot, soapy
water in a hydropulper. Researchers found that the asbestos fibers, with
-------
positively charged surfaces, are readily dispersed in water treated with
certain soaps.6 The process yields a dense yarn by extruding the dispersion
slurry and passing the material through spinnerettes. Similar with respect to
viscose rayon processing, the Novatex process eliminates the carding
operation; the segment of the conventional process that generates a great deal
of airborne fibrous dust.
Primary asbestos textile products are typically fabricated into
industrial, commercial and consumer products by secondary manufactirers.
Table 23 identifies the end products made using primary asbestos-containing
textile materials. In 1975, the market shares of asbestos textiles used for
friction materials, packing and jointing material, protective clothing,
thermal and electrical insulation, layer felts, and conveyor belts were 30,
27, 17, 13, 7 and 6 percent, respectively.1 In most cases, asbestos textile
materials are bound or coated with resins or elastomers before becoming the
final product.7 Asbestos material can also be aluminized forming a heat
reflecting surface. The metallic layer can be sprayed on or bonded to the
cloth by a thermosetting resin.
TABLE 23. FORMS OF ASBESTOS TEXTILES USED IN ASBESTOS PRODUCTS7
Fire-
resistant Thermal
clothing insulation
Yarn Yarn
Thread Cloth
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
The demand for asbestos in textile manufacture is estimated to fall to
zero tons in the year 2000.^ The performance of high temperature
application substitute materials has proven comparable with and often exceeds
95
-------
the performance characteristics of asbestos.7 Large producers of
fire-resistant materials are currently manufacturing substitutes containing
fiberglass and ceramics along with their asbestos products as government
specifications for fire-resistant materials are being revised for health
reasons, thus encouraging the sale and use of substitute materials.'.
SECONDARY AND CONSUMER USE
As discussed previously, primary asbestos-containing textile materials
are further processed by secondary manufacturers. As an example, electrical
wire manufacturers may use asbestos tubing as insulating material. The
consumer product is the electric wire itself or the fixture or appliance the
electric wire may be a part of.
The following paragraphs describe asbestos textile product uses and
potential consumer exposure. It is important to remember that
asbestos-containing textile materials are generally bound or coated with
resins or elastomers before becoming the final product; this minimizes
consumer exposure during product use.
Fire-Resistant Materials
Whenever the properties of incombustibility and thermal stability are
required, asbestos-containing cloth is generally used. Woven from asbestos
yarn, the variety of asbestos cloth applications include welding curtains,
draperies, blankets, protective clothing, hot conveyor belts, furnace shields
and molten metal splash protection aprons. All of these are industrial
applications and do not represent general consumer uses.
With respect to consumer uses, the Consumer Product Safety Commission has
bannC'l general use of garments containing asbestos. However, the use of
asbesios in special garments, such as fire-fighting protective clothing, is
permitted if the materials are made so that asbestos fibers are not released
under normal use. Asbestos cloth is generally treated during processing such
that direct exposure to asbestos fiber will not occur until the product wears
out or becomes torn.
Thermal Insulation
Asbestos textiles, such as cloth, tubing, and tape, are used as thermal
insulation. Applications include pipe wraps for safety protection, stress
relieving pads in welding operations, protective coverings for hot glassware
utensils, coverings for diesel engine exhaust lines, and braided walls in the
construction of steam hoses.7 Again these are primarily industrial and
commercial uses, not consumer applications which would affect a greater
population.
Exposure co asbestos fibers can occur during installation when the
textile product may be cut or torn for proper application. "Rip-outs" or
removal of unuseable or worn-out asbestos material generates the highest
R
concentrations of asbestos fibers encountered by insulation workers.0
96
-------
Electrical Insulation
Asbestos tubing, tape, and cloth have a wide variety of applications in
the electrical industry providing insulation and heat resistance.*• As a
conductor covering, braided tubing or tape may be wrapped on wire (or cables),
or plastic laminated and pressed onto wire. Generally, asbestos textiles are
employed for the insulation of wires and cable which are designed for low
voltage, high current use under severe temperature conditions.7
Under proper use, direct exposure to asbestos fibers from insulated
electrical products is expected to be minimal. However, electric.il appliance
cords may become frayed (cloth covering) under abnormal use, in which case
asbestos fibers could become airborne.
Packing Material
Asbestos textile packing is manufactured from dry asbestos yarn which
is impregnated with a lubricant and braided into continuous lengths. Varying
amounts of binder and lubricant may be added depending on the application.
The most common type of rotating shaft seal consists of packing composed of
woven, twisted or braided textile yarns and threads which are formed into
coils, spirals or rings.' Similar packing material may be used in slip-type
expansion joints. In both cases, asbestos fiber release is related to the
lack of lubricant which causes packing material to become hard and lose its
resiliency. Lubrication fittings are generally provided on pumps and slip
joints so that adequate quantities of lubricant can be supplied regularly.
Friction Material
Asbestos textile materials in the form of woven asbestos brake lining or
clutch facings are mainly found in industrial applications where long periods
of heavy load conditions exists. Molded asbestos brake materials, developed
in the 1950"s, are replacing woven textile products because they offer
superior fnotional properties.* Woven asbestos brakes are reinforced with
brass wire or impregnated with phenolic resin. Exposure to asbestos fibers
during use is expected to be similar to other friction materials.
Specialty Textiles
Carded fiber is the main form of asbestos that can be used in specialty
products.^ Carded asbestos fiber (100 percent asbestos) is used as a
filtering media in the clarification of beer, wine, oils and chemicals.
Carded asbestos fiber can be furnished in many degrees of fineness to provide
exactly the right screening for the liquid to be filtered.3 The life span
of this material is dependent upon its application, but usually lasts only one
cycle. Carded asbestos fiber is packaged by the manufacturer in cartons
and boxes. Use of this material is generally associated with a large scale
brewery or distillery operation.
97
-------
ENVIRONMENTAL RELEASE.
Asbestos fiber release'monitoring data associated with textile use are
scant. A few studies have been performed, covering a limited number of
textile products. The following presents the monitoring results that have
been obtained from the literature.
Tests to determine fiber release while wearing asbestos garments were
performed at a blast furnace and a phosphorous plant where asbestos coats,
hoods and mittens are worn. Personal monitors were used to measure the
concentration of asbestos fibers at the breathing zone level. Asbestos fiber
concentrations of 0.3 to 5.0 fibers/cm^ were recorded for a blast furnace
worker with an 8-hour TWA concentration of 0.1 to 1.1 fibers/cm-*.10 At
the phosphorous plant, asbestos fiber levels were considerably higher; 9 to
26.2 fibers/cm-*, with an 8-hour TWA concentration of 4.7 fibers/cm^.lO
No reason was given for the difference in concentrations recorded at the two
plants.
The garments tested were made 'of an untreated fabric. However, hoods
were aluminized on the outside. The age of the garments was also examined in
the study. Generally, asbestos fiber release increased with product age,
however, no firm correlation could be developed.
Measurements of asbestos fiber release from fire-fighting helmets during
use were made in another study.11 Testing of a new helmet with an unlined
asbestos cover, an identical older helmet, and a helmet with an aluminized
cover on the inside and outside surfaces, showed breathing zone concentrations
of 2.30, 1.38, and 0.0 fibers/cm-*, respectively.11
With respect to worker exposure during the handling and use of thermal
insulation, the highest concentration of asbestos fiber exposure occurred
during "rip-out" or removal of old asbestos insulation." Asbestos air
levels monitored on a ship during the removal of sprayed asbestos coatings,
removal of 100 percent asbestos lagging, and clean-up operations averaged 248,
62 to 159, and 353 fibers/cm-*, respectively.8 The high levels of asbestos
fiber exposure are probably attributable to: (1) percent of asbestos content
in the insulating material, (2) the untreated nature of asbestos material that
becomes exposed to the atmosphere during removal operations, and (3) poorly
ventilated conditions existing during installation and removal operations
(shipbuilding). A study investigating the installation, of pipe lagging
containing 15 percent asbestos, reported asbestos fiber exposure levels of 5
to 60 fibers/cm-'.12 it should be noted that the above data are relatively
old and that substantially more effective control measures are now implemented
during insulation removal.
A more recent study1-* has shown that asbestos-containing gloves release
asbestos fibers during use. Asbestos gloves, which are manufactured from
asbestos-containing textiles, are commonly used in hospital, industrial and
university laboratories where sterilization is done and in the molten metal
industry where worker protection from handling hot items is required. These
types of gloves contain from 80 to 85 percent asbestos and 15 to 20 percent
98
-------
rayon. The clolh of the gloves tested was treated with an acrylate-based
compound which enables the manufacturer to market them as "Lint free."
Three tests were performed as part of the referenced study. The fiber
release monitoring experiments included testing in a ventless isolation
chamber (glove box), a well-ventilated (five air changes per hour) biology
preparation room and in University laboratories under conditions of actual
glove use. The researchers examined the potential difference in fiber release
from new and worn gloves, the latter varying from clean to heavily soiled.
The glove use activities included the following: (1) picking the gloves
up from a table top and putting them on; (2) opening an autoclave or oven
door; (3) removing a tray containing laboratory growth media or glassware and
setting the tray on a table top; (4) closing the door; and (5) taking the
gloves off and tossing them onto a table top. The results of the three test
cases are summarized in Table 24.
In all cases, fiber release was found to be directly related to the
condition of the gloves. Under the npnventilated isolation chamber
conditions, the well-worn/clean gloves emitted almost three times as many
fibers as did the brand-new gloves, although the number of fibers released
from the well-worn gloves decreased with increased surface soiling.
TWA values recorded for the well-ventilated biology preparation room were
considerably lower than those,obtained in the ventless isolation chamber. The
authors postulate that the lower levels result from dispersion of fibers
within the room by the ventilation system. The findings of the biology
preparation room testing concur with those of the ventless isolation chamber
whereby the well-worn/clean gloves emitted a significantly higher number of
asbestos fibers into the atmosphere than the brand-new gloves did. Fiber
concentrations also increased with work load, as one would expect.
Monitoring tests conducted in various University laboratories revealed a
wide range of fiber Levels. The researchers state that exposure levels
depended more on the particular laboratory than on glove condition or usage
(work load). The range in values reported are thought to be attributed to
differences in room size and configuration, efficiency of the ventilation
system and amount of moisture on the gloves. In summary, the researchers
conclude from their tests that the use of asbestos-containing gloves expose
the wearer to potentially hazardous levels of asbestos and suggest gloves made
from asbestos substitute material be used whenever possible.
Asbestos fiber release during primary and secondary manufacturing
processes have been widely documented. Table 25 presents the exposure levels
measured during asbestos textile manufacturing. Asbestos dust levels from
primary and secondary manufacturing of wet-processed asbestos textile are
99
-------
TABLE 24. AIRBORNE ASBESTOS FIBERS3 RESULTING FROM THE USE OF
ASBESTOS-CONTAINING GLOVES13
Sampling environment
Condition of gloves
and work load
Mean TWA + SD
(E/cm37
Isolation chamber
(nonventilated)
Biology preparation room
(well ventilated)
Breathing zone
Work area
University Laboratories
Breathing zone
Work area
Brand new
Well-worn/clean
Well-worn/lightly soiled
Well-worn/heavily soiled
Brand new - normal''
Well-worn/clean-normal
Brand new - heavy0
We11-worn/clean-heavy
Brand new - aonnal
We11-worn/cloan-normal
Brand new - heavy
Well-worn/clean-heavy
Well-worn/clean
Well-worn/lightly soiled
Well-worn/clean
Well-worn/lightly soiled
2.25 + 0.57
7.97 _* 3.14
5.08 + 1.27
0.95 + 0.16
0.07 i 0.02
0.49 + 0.11
0.51 + 0.21
0.99 + 0.22
0.06 + 0.02
0.40 + 0.09
0.26 + 0.08
0.60 + O.L2
0.07 to 2.93d
0.10 to 0.71
0.04
0.30 to 0.74
''Asbestos fibers counted were 5 urn long or longer with a len ;ch to
width aspect ratio of 3 to 1. Phase contrast optical microscopy analysis
was performed.
^Normal usage of gloves two times per hour.
cHeavy usage of gloves six times per hour.
dValues reported are not means; ranges are from tests performed at
five different laboratories.
LOU
-------
generally lower than levels for dry-processed materials. Dust level
measurements in the manufacture of insulation mattresses with wet-processed
"Fortex" asbestos cloth showed asbestos fiber concentrations during cloth
pr«|>«mit Lim and mnCLrrss making of (J.28 to 0.58 ami 0.29 to 0.6 fibers/cm-*,
respectively.^
TABLE 25. EXPOSURE TO AIRBORNE ASBESTOS FIBERS DURING PRIMARY AND
SECONDARY TEXTILE MANUFACTURING8
Asbestos concentrations
(Time-weighted average in fibers/cm^)8
Most operations Operations with highest level
Manufacturing
operation Typical Range Typical Range Operation
Primary
Second dry
A 0.25-10 4
2.0 - 6.0
2.0-10 Carding
al'ibers 5 urn long or longer, having a length to width aspect ratio of
l!:l were counted by Phase Contrasp Optical Microscopy Analysis.
In summary, all testing has shown that surface treatment of asbestos-
containing textile material, whether it be during processing or prior to
consumer use, generally lessens the danger of asbestos fiber exposure. All
tests with asbestos garments suggest that the safety provided may outweigh the
risk of asbestos-related diseases, however, the tests also show that proper
treatment of asbestos garment materials, such as aluminization of cloth
surfaces, can eliminate the risk entirely.
101
-------
REFERENCES
1. Sores, Inc. and Arthur D. Little, Inc. Characterization of the U.S.
Textile Markets. Ministers De L'Industrie Et Du Commerce, Government Du
Quebec. Final Draft Report. May 1976.
2. Cogley, D., et al. Life Cycle of Asbestos in Commercial and Industrial
Use Including Estimates of Releases to Air, Water, and Land. Draft Final
Report prepared by GCA/Technology Division for U.S. Environmental
Protection Agency, Office of Toxic Substances, Washington, D.C. October
1979.
3. Anon. Handbook of Asbestos Textiles. American Textile Institute. 3rd
Edition. 1967.
4. Clifton, R. A., Asbestos. 1980 Minerals Yearbook. U.S. Bureau of Mines,
Washington, D.C.
5. Meylan, W. M., et al. Chemical Market Input/Output Analysis of Selected
Chemical Substances to Assess Sources of Environmental Contamination:
Task III - Asbestos. EPA Report No. EPA-560/6-78-005. August 1978.
6. Scott, S. W. Produce Asbestos Yarn, Safely. Textile World. 131:69.
March 1981.
7. Krusell, N., et al. Asbestos Substitute Performance Analysis. Final
Report prepared by CCA/Technology Division for U.S. Environmental
Protection Agency, Office of Toxic Substances, Washington, D.C.. May
1981.
8. Levine, R. J. (ed.). Asbestos: An Information Source. DHEW Pub. No.
(NIH)79-681, May 1978.
9. Perry, R. H., and C. H. Chilton. Chemical Engineer's Handbook. Fifth
Edition. McGraw-Hill, New York, 1973.
10. Gibbs, G. W. Fibre Release from Asbestos Garments. Ann. Occup. Hyg.
18:143. 1975.
II. LumLey, K. P. S. Asbestos Dust Levels Inside Firefighting 'lelmets with
Chrysotile Asbestos Covers. Ann. Occup. Hyg. 14:285. 1971.
102
-------
12. Harries, P.G. Asbestos Hazards in Naval Dockyards. Ann. Occup. Hyg.
11:135-145. 1968.
13. Samini, B. S., and A. M. Williams. Occupational Exposure to Asbestos
Fibers Resulting from Use of Asbestos Gloves. Am. Ind. Hyg. Assoc. J.
42:870-875. 1981.
14. Schneider, T. Asbestos Dust Levels During Work with Cloths Made from
Liquid Dispersed Chrysotile. Ann. Occup. Hyg. 15:425. 1972.
103
-------
SECTION 10
ASBESTOS-REINFORCED PLASTICS
INTRODUCTION
Asbestos fibers are used to reinforce high grade plastics for many
applications where precision and specialty plastics are called for. The
asbestos content of these materials is generally quite low.^
Asbestos reinforced plastics are extremely versatile. They can be
applied for many uses which call for impact resistance, dimensional stability,
heat resistance, dielectric strength, insulation resistance, arc-trac
resistance, and ability to retain electrical properties at elevated
temperature and humidity.2
Products manufactured from asbestos reinforced plastics include:^
• automotive parts
• communications products
• drafting tools
• precision engineered parts formerly made from metals
• electrical components
• appliance components
Once the .plastic products are fabricated and ready for use, the potential
for asbestos fiber release is highly unlikely; the fibers are bound tightly in
the product's polymer matrix. A great deal of energy needs to be applied to
the plastic in order to release any amount of fiber.*•
PRODUCT MANUFACTURING AND COMPOSITION
Two processing steps are involved in the manufacture of
asbestos-reinforced plastic products. The two steps are primary manufacturing
using commercial asbestos fibers and secondary manufacturing or fabricating.
Primary manufacturers produce molding resin compounds in pellet or flake form,
package it, and sell this granulated material to secondary manufacturers where
104
-------
the final product is shaped (molded) and finished. The primary manufacturing
seeps consist typically of: (I) 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 processor and consist or: (1) resin receiving and
storage, (2) resin introduction, (3) forming, (4) curing, (5) finishing, an>l
(6) product packaging and shipping to consumers.^
It is extremely difficult to determine the entire scope of the secondary
market for asbestos-reinforced plastics. There are industry estimates of some
3,000 secondary fabricators of reinforced plastics and perhaps 5,000 separate
end users of the product.^ Also, it is impossible to determine what
percentage of these plastic fabricators presently use asbestos-reinforced
plastics. It has been reported, however, thit many secondary manufacturers
have decided not to process compounds containing asbestos fibers in their
operations and have already converted to asbestos-free compounds.5
The volume of asbestos used in the plastics industry is declining rapidly
according to Bureau of Mines estimates. In 1976, 19,500 metric tons of
asbestos were reported to be consumed by the plastics molding industry; by
1978 this figure declined to 4,900.^»^ The 1980 figures indicate a further
reduction to only 1,500 metric tons of asbestos.? This decline can be
attributed to the use of a large variety of asbestos substitutes in the
industry. The asbestos that is used, however, consists primarily of
crocidolite and chrysotile grades 1, 2, 5, and 7.7
SECONDARY AND CONSUMER USE
Asbestos-reinforced plastics are used in a great number of diverse
applications. Most of the applications are related to commercial or
industrial operations, few represent consumer uses. Molded
asbestos-reinforced plastic products are predominantly used in the electronic,
automotive and printing industries. Such product applications include
asbestos-reinforced board material used in the printing industry as a matrix
from which multiple rubber or plastic printing plates caii be molded;
automotive transmission reactors which are employed to direct the flow of
transmission fluid; and commutators for electrical motors, switches and
circuit breakers.^
The life span of many of these items vary, most are less than 35
years.8 Some, such as automotive parts, may have a very short useful life.
However, even during handling and replacement there is no significant exposure
hazard from the asbestos content of the products. The a.bestos is safely
bound in the polymer matrix. Eighty to ninety percent 01 tne
asbestos-containing plastics produced are for replacement components.& In
1978, annual wasting of asbestos-containing plastics was estimated to be
around 18,000 tons.**
105
-------
ENVIRONMENTAL RELEASE
Molded reinforced plastic products are usually finished to a form where
installation for use generates negligible dusting. Secondary finishing
operations include drilling, filing, grinding and some riveting. Tests
performed under laboratory conditions have shown that asbestos fibers are
released during secondary finishing operations.^ Grinding, filing and
drilling tests resulted in fiber levels ranging from 0.0 to 7.1 f/cnr* as
shown in Table 26. Asbestos fibers identified occurred in short bundles and
were encapsulated in the plastic matrix, r'ree individual fibers were also
detected.
TABLE 26. ASBESTOS FIBERS CONCENTRATIONS ASSOCIATED WITH
REINFORCED PLASTIC SECONDARY FINISHING OPERATIONS9
Time SEM^ analysis
Operation (min) (f/cm-*)
File
File (repeat)
Drill
Grind
1 0
3 1.6
3 0
j 1.6
Phase contrast analysis
(f/cm3)
0
2.8
7.1
2.8
aFibers 5 urn long or longer with a length to width aspect ration
of 3 to 1 were counted.
^Scanning electron microscopy analysis.
Asbestos fibers ar
-------
REFERENCES
1. Daly, A. R., et al. Technological Feasibility and Economic Impact of
OSHA Proposed Revision of Asbestos Standard (construction excluded).
Prepared by R. F. Weston for Asbestos InJormation Association/North
America. March 26, 1976.
2. Durez/Hooker. Durez Thermosetting Molding Compounds Bulletin 328
MPLOM878. Ourez Division, Hooker Chemicals and Plastics Corp., N.
Tonowanda, New York.
(K)
3. General Electric, Genal F7000 Series, New High-Performance Engineering
Plastics to Replace Metal. G. E. Plastics Division, Pittsfield,
Massachusetts.
4. Cogley, D., et al. Life Cycle of Asbestos in Commercial and Industrial
Use Including Estimates of Releases to Air, Water and Land. Prepared by
GCA/Technology Division under EPA Contract No. 68-02-2607 for U.S.
Environmental Protection Agency, Office of Toxic Substances, Washington,
D.C. November 1981.
5. Swanson, R. C., Sales Representative, Colt Industries, Garlock Inc.
Mechanics Packing Division, Charlotte, North Carolina. Meeting with Mr.
T. Curtin, GCA/Technology Division, Chapel Hill, North Carolina.
February 21, 1980.
6. Clifton, R. A., Asbestos: A Chapter from Mineral Facts and Problems,
1980 Edition. Bureau of Mines Preprint from Bulletin 671. 9 pp.
7. Clifton, R. A., Asbestos: In 1980 Minerals Yearbook. U.S. Bureau of
Mines, Washington, D.C.
8. Meylan, W. M., et al. Chemical Market Input/Output Analysis of Selected
Chemical Substances to Assess Sources of Environmental Contamination:
Task III - Asbestos. Report prepared for U.S. Environmental Protection
Agency, tPA-560/6-78-005. August 1978.
9. Cogley, D., et al. The Experimental Determination of Asbestos Fiber Size
Distribution During Simulated Product Use. Prepared by GCA/Technology
Division for the U.S. Environmental Protection Agency,--Office ot"
Pesticides and Toxic Substances, Washington, D.C. October 1981.
10. Gormley, J. F. Submittal of Westinghouse Electric Corporation to U.S.
Environmental Protection Agency's Office of Toxic Substances Eor
Inclusion Into Docket OTS 61005: Commercial aid Industrial Use of
Asbestos Fibers; Advance Notice of Proposed Ruleraaking.
107
-------
SECTION 11
CONCLUSION AND RECOMMENDATIONS
SUMMARY OF FINDINGS
This study was undertaken to provide an analysis of asbestos fiber
release concentrations resulting from routine activities performed on
asbestos-containing products and to prioritize products for subsequent
laboratory testing. Products to be tested under this program are those for
which data is insufficient or lacking in quality. Routine activities to be
reenacted are those which are commonly or most frequently performed and those
which are most likely to release free form asbestos fibers.
Product category profiles were developed to provide the information
required to select the products to be tested under this program and to
identify candidate products to be tested under future monitoring programs
sponsored by EPA. Fiber concentration data reported were obtained from
technical reports, trade journals, and contacts with environmental regulatory
agencies and industry representatives.
As summarized in Table 27, the quantity and quality of the asbestos fiber
release data varies greatly between product categories and among products
within each category. In addition, measured fiber concentrations even vary
among tests performed on similar products. These Latter variances are
attributable to monitoring in a glove box versus monitoring in a
well-ventilated room or out of doors; employing dust control measures during
some tests but not during others; differences in sampling location and
analytical techniques; and differences in product composition. Consequently,
meaningful comparative analysis of the test results is restricted.
The magnitude and severity of human exposure during asbestos product
handling and use depends upon the releasibility of the fibers, strength of th»
exertion or force of agitation, fiber sizes released, and duration of the
activity. During normal handling and intended use, many asbestos-containing
products will not release asbestos fibers. Only during maintenance or
replacement will the' product be acted upon such that it may pose a potential
health hazard. Furthermore, due to their rigid physical structure, many
asbestos-containing products are used in stationary or static applications.
Once in place, the Material is subjected to little or no direct physical force
or abrasion.
108
-------
TABLE 27. MEASURED ASBESTOS FIBER CONCENTRATIONS RESULTING FROM SECONDARY AND
END USE PRODUCT TESTING ACTIVITIES
a
vc
ca;, ior\ ^sbeslos product Activity perfornad
p.pe Hack saw
Snap cutting
Abrasive disct uet
Abrasive disc, dry
Cnlsel. liacntr. and rasp
Machining Operations
Manual lathe
Power lathe
Doty nachine dry
Dry bhroud
Uet sliroud
Tapering cool with
airduct pips
Hole Cuttl ig
?owe.hule Butter
Hole culling with drill.
hairmcr and rasp
Dry tap with Mueller J
to.il
Tapping operations with
Mueller B-1GO
Couoling Removal
i>
0.18
<0. 10
42.10
35.50
0.30
0.15
<0. 10
3.83
0.23
0.20
0.18
0.44
0.23
<0. 10
-0.10
<0.1U
f o in
' U. IU
Date of
tests
1979-1980
1979-1980
1979-1920
1979-1983
1979-1980
1979-1980
1979-1980
1979-1980
1979-1980
1979-1980
1979-1980
1979-1980
1979-1980
1979-1980
1979-1980
1979-1980
1979—1980
Duration of
activity/
sampling
time
(mm)
lls
i15
i15
I15
I1*
I13
i15
I15
i15
1 e
< 1 J
05
<15
<15
< 15
«.15
L15
1C
< U
Analytical
method
NIOSH
NIOSH
NIOSH
NIOSH
NIOSH
NIOSH
NIOSH
NIOSH
NIOSH
NIOSH
NIOSH
NIOSH
NIOSH
NIOSH
HlOSd
NIOSH
NIOSH
Method*
Method
Method
Method
Method
Method
Method
Method
Method
Method
Method
Method
Method
Method
Method
Method
Method
Comments
Personal
operator
Personal
operator
Personal
operacor
Personal
operator
Personal
operator
Personal
operator
Personal
operator
Personal
operator
Per tonal
operator
operator
Personal
operator
Personal
operator
Personal
operator
operator
Personal
operator
Personal
operator
operator
aoniCor
.
monitor
.
aonicor
toon L Cor
.
monitor
•
nan L tor
monitor
.
monitor
.
man L tor
-
monitor
oonitor
Donicor
monitor
monitor
oa
oa
on
oa
on
on
oa
on
on
oa
on
oa
oa
00
Ref
I
I
1
1
1
1
1
1
1
i
i
i
i
i
i
i
(continued)
-------
TABLE 27 (continued)
i93>. .: •» ?- JJ.CL
^jle^ji, Asbestos product Activity performed
S
pipe (continued) P*Pe
Chisel. haCiner. and rasp
Machining Operations
Manual lathe
Power lathe
Cutting jnJ machining
on Do:y niihinc dry
Dry shroud
Wet shroud
Hole Cutting
P*jw.frholi cutcer
li^ • -r n nonitor on
OKr*:or.
Testing perfomed in
glove box.
Testing performed LD
glove box.
Testing pexforaed ia
glove box.
Bef
1
I
1
,
1
1
1
1
1
1
1
1
1
2
2
2
(continued)
-------
TABLE 27 (continued)
CiU = jry
\»t«estos product
Activity performed
Measured
fiber
concen-
tration
(f/c*J)
Date of
tests
Duration of
activity/
tine
(mm)
Analytical
\»3c.»(0d *~;tir A*.*e*to» pipeline Tear 0-0.9
(«.ont i.-iueJ) wrap
Crumple L.9-14.S
Millboard Siore 8.4
ij-uisr 1.4
Saw 4.2
?51 asbestos house- Cutting 2.0-2.2
hold l)3?or roll (.13.3-
23.3)b
*3. .ishcbLo* noj»e- Tearing 2.3
!..•>..! fj-jor roil (8.9)
23* 3,le-.[j:, "ious«- Tearing and cutting 4.8
hold 3d}.cr roll (27.6)
75* a»besLos comber- Tearing and crumpling 7.3
ci3l pjper (58.9)
c .-c .ru-jpl i-.s C62)
7J. io bul j53«.*Los Cutti-ni,, rubbing, rolling, 24
7i,. to SOI js'j«>:o3 Cutting, rubbing, rolling, IB
Electrical insulating Sc.-rling nagn± ply
pjper and buards1' package operator
<0.016
1981
1981
1980
1980
1980
1980
1980
1980
1980
1930
1979
1979
1980
1 to 3
3 to 4
10
10
10
10
10
10
10
10
10
10
43
NIOSH Method
NIOSH Method
SEMb
NIOSH Method
(StM)
NIOSri Method
(SL-O
NIOSH Method
(SEM)
NIOSH Method
NiOaH M^chod
Polarized light
microscopy0
Polarized light
microscopy
Ph.se contract
Testing performed in
glove box.
Testing performed in
glove box.
Testing performed in
glove box.
Testing perfarced ia
glove box.
Testing performed in
glove oox.
Testing performed in
glove box.
Testing perfomed in
glove box.
Testing performed in
glove box.
Testing performed in
glove bot.
Testing pcrforasd in
glove box.
Tests performed in-
side 30.3«43.2x43.2
cm glove box.
Tests per£or=ed in-
side JO.3*43.2x43.2
en glove box.
Results froa moni-
toring electrical
insulating paper
products manufac-
tured by Quin-T
Corporation.
(continued)
-------
TABLE 27 (continued)
leisured
eoncen-
Ait^LJS product tratian
category Asbestos piuJuit Activity performed (£/cm*)
A±b*»:os pa^ar Electrical Insulating Paper machine rewind < 0.004
\cor t iri<£ J) paper o*iJ bourns •'r * 'a tor , 0. 000 en
pj|>i.r
Paper -aechine rewind <0.006
operator, 0.04 cm
thick paper
t.i'.lbojrd cutter operator <0.005
0« OS cm tii icic. popisr
UmJing operator. 2 3
ri Luh l>inJer slitter 0.53
operator
Duration of
activity/
sacpling
Ddte of time " Analytical
tests (n»in> method Cements
1980 178 Phase contrast Results from ooni-
products manufac-
tured oy Quin-T
Corporal ion.
1980 112 Phase contrast Results from moni-
toring electrical
insulating paper
products manufac-
tured Sy Quin-T
1980 141 Phase contrast Re&jlts frocc cjni-
tnsulating paper
products manufac-
tured by Quin-T
Corporation.
1980 90 Phase contrast Results froa moni-
toring electrical
insulating paper
profile: a oanutac-
turoJ Ly Q^ir.-T
Cur^orat ion.
1980 90 Phase contrast Results from ooni-
toring electr.cal
insulating paper
products nanufac-
tured by Quin-T
Corporatior.
1978 30 Phase contrast Reference c.tes
toring electrical
insulating paper
product* manufac-
tured by Quin-1
Corporat ion.
Kef
5
3
S
S
3
5
(continued)
-------
TABLE 27 (continued)
Asbiis:oa prodjct
tJLegory Asbestos product
Hen
fi
con
tra
Activity perfor-ned (£/
ured
er
en-
ion Date of
m') teati
Durat ion of
activity/
sampling
time
(•in)
Analytical
method
Consents Ref
Electrical in&ulating Coil cutler operator
paper and boards
COL! cutter operator
Acme paper cutter
Acne coil cutter
Acne conv. winding
Winding operator,
0.008 cm thick paper
SlitLing operator,
0.00a en Lhick paper
0.094
0.015
-------
TA3LE 27 (continued)
Ksbes£o» product
category Asbestos produce AcC ivity performed
(c.a; L.i^tiJ paper and boards paper-punch press
optfi-jcjr CTV &ORD)
Electrical insulating
paper--shear operator
(TV BORD)
Electrical iisulutlng
pjpcr — jbsenbly Jept.
op^r^L^r vLV dOilD)
NECO, shear machine
operator
NIXO. winding .in.- a
operator
Ac cc licdv) haiiJtiLnJing
Acoe coil pulling
Nriasurcd Duration of
liber activity/
eon Jen- sampl ing
t rat ion Date of tine Analytical
( f /en3) testa (am) me C hod Comment* Rcf .
0.097 ND 298 Phase contract Resulta from mom- S
coring electrical
ir» lac Liy pap<:r
procure A nanufa;-
t u red by Qu i n -T
Corporation.
0.064 KD 153 Phase contrast Resells froa ooni- 5
insulating paper
products manufac-
tured by Quin-T
Corp^rat ion.
t^r^i^ clectricil
•>• insulating pa^er
products aanufac*
tured by Quin-T
Corporat ion.
0.033 1978 120 Fhaae contrast Results from com- 5
insu'taMng paper
products .iianufac-
tjrej ^, (Juiu-T
Corporation.
0.033 1978 180 Phase contrast Results iroxnm- 5
insulating paper
products manufac-
tured b> Quin-I
Corporation.
<0.006 1979 108 Phase contrast " . OM I.UHL- 5
torinj electrical
ir.iulai.'i paper
products oanutac-
tured b> Quin-T
Cj.-;--*tion.
toring electrical
insulating paper
products manufac-
tured oy Quia-T
Corporation.
(continued)
-------
TABLE 27 (continued)
(continued) paper and boards
KesiniLc band saw
operator
Square D saw operator
flaor •.«,; l«jlt attached
to vinyl she*±t
flooring
Partial reoiova 1 by
Coi |>l t c e T*.' ~*j\ j I uy
fv kh>'*>.iitf nd«jU uroci.'Jjr£S
Complete reaoval by
recouvnended procedures
Complete rci oxal
Wear lay*M reroval
Dry acrdping of flooring
felt
U'«! t bC rap i n£ of f looring
felt
M* .isurtfii Durat ion of
f ib*r act ivity/
conc^n- caopling
tr^tion Dace of tinu Analytical
( £/ca ) ttists Coiin) method
0.062 1980 111 Phase contrast
0.102
(TWA)
0.041
0 0<>
0.007 to 1979 74 to 76 Phase contrast
0.01
(TWA)
0.3d Co 1979 70 Co 75 Phase co-icrjcc
0.16
(T»'n)
0.8} to 1979 40 Co 6} Phase contrast
2.0
(TUA)
(TWA)
Comment • ftef.
insulating paper
products manufac-
tured by Quin-T
Corporation.
insulating paper
products manufac-
tured by Quin-T
Corporation.
Results from ooni- 3
toring electrical
ir.kt.laiiiig paper
ur_-c oy wJia-T
four adhering and
one nonadhe r i ng
appl ic.itions.
Material removed 6
nad ocen ariliered ;o
sul:lojm,4.
been adhered to
subf looring.
Material removed had 6
not been adhered Co
subtioonng.
Material removed .iad 7
bttin Adnered to
subf looring.
Material reooved had 7
been adhered to
subf looring.
been adhered to
cubtlooring.
(continued)
-------
TABLE 27 (continued)
Measured Duration of
fiber activity/
coneen- sampling
i.cl tratun Date of tme Analytical
Asbestos proiucL Activn> perlorned (f/ci3) tests (mm) nethod Co=.-ienti Ref.
rnctiau ur.iil.it. is Br.k* and clutch Receiving jnd cleaning 0.4-7.6 1976-1977 ND NIOSH Method
assembly rebuilding
(assumed)
Bonding and riveting 0.2-5.8 1976-1977 ND NIOSH Method
(as*u"aed)
Cutting and grinding 0.8-9.) 1976-1977 ND NIOSH Method
(assumed)
Inspection and packa.-.ig 0.8-1.1 1976-1977 ND NIOSH Method
(assumed)
Not clear in refer-
ence how brake and
clutch activities
diirer.
Not clear in refer-
ence how orane and
clutci activities
oititr.
Not clear in refar-
clutch activities
differ.
Hot clear in refer-
ence now bra*e iat
clucch activities
differ.
brakes
True,, brutes
Fl Hi' • i^ pr j '1.1 I &
Vlnjl-
cile
Blowing dust uut of brake
drums with cjmprs»seJ
air
Monitoring dmrancp
0.9-1.5 m.-c^r>
Moiitor.ng J. si nice
l.i-3.0 i tter»
rjn.torin^ l..;.in..e
3 0-ft T-lf ILI
Renew. 'i^'uied linings by
^r i i.liu£
~.j-\ 'j -wtcra
5evirlin£ tiuw linings.
MJ.T. -.01 1 !„ Ji>tdn;e
0 9-1. > outers
>r Cut
Grind
Break
6.6-29.8
3.0-4.2
0.4-4.8
1 . 7—7.0
23.7-72.0
0
0
(O.i)
0
1976
1976
1976
1976
1976
1981
1981
1981
ND NIOSH Method
ND NIOSH Method
•ID NIOSil Method
ND NlOSrl He thud
ND MJSH Methoo
5 NIO<:M M.-rhM
3 NIOSH Method
(SLM)
3 MIOirt Method
Testing perforced ia
glove box.
Testing performtd in
glove DOR.
Te&ti-.ft ^c^iormed in
glove box.
9
9
9
9
2
2
2
(continued)
-------
TABLE 27 (continued)
AsD.-stos pruouct
cjt.^Jty
: = lt» un.c i ^r«
ci\ i. -tfd un»vr
(co-it inuedj
Asbestos product
fiber
concen-
tration Date of
Activity pcrfonred C/cr=3) testa
V.-> l-a^bcsios t loor Drill 0 1981
cleaning 0.06
Duration of
act ivLty/
sanpl ing
tiae Analytical
(mm) method Coanents
1 NIOSri vethod Testing perforxed in
glove aju.
reported. Nat
tests.
Rcf
2
10
Flooring retaovil, ripping
up tiles
0.02-0.1
1980
16S
SEM
Flooring removal by
SJnJint; ruugh cur faces
Pedestrian traffic on
floor tile
Flo
Hopping
fing
ng n~iliite-i3r.ee,
1.2-1.3
0.0
0.0
0.0
1970-1971
1979
1979
1979
20
IS to 21
11 to 30
Phase contrast
130 to 420 Phaie contrast
Phase contrait
Phase contrj»t
Monitoring perfon&ed 3
during actual
Iloori1^ rtaova1.
Re»uLcs dr«f sore
indicative of
Levels nearby the
workplace than rhoie
actually experienced
fay the worker.
Sic'ilatcJ testing in 11
labora.ory cnanber
3*3.7x2.1 -aetera
with four air
c^an^es/hr. Belt
aander with coarfie
paper ubed.
Honicoring occurred L2
in an oifice setting,
the areas fcXd*Lin*.d
were a ;iolocopying
room ai- a snacX
shop.
Activity was per- 12
forced on floor tilei
located in photo-
copying roo*a and
snack sho^.
Activity -as per- 11
f,: ..j os floor tiles
LocateJ in photo-
copying roaa and
anack sbcp.
(concinued)
-------
TABLE 27 (continued)
oo
fiber
concen-
*»b«tii>5 product t rat ion Dace of
category Asbestos product Activity performed (f/cm*) tesca
(T.'A)
Installation by 0.008 to 1979
recoomended procedures 0.027
(1VA)
Installation by 0.935 to 1979
r.fcorvu.n.ied procedures 0.01
(TVIA)
Old tile preparation for 0.0 1979
new installation (TVA)
Cjirpl£:e r*.rovjl by 3 0.12 to 1979
method thoc deviates from 0.33
Installation by recommended 0.016 Co 1979
procedures 0.032
(FUA)
!._•> ._ j „ > ..» S ^ t, p
»""•-»
Duration of
activity/
sampling
time Analytical
(mm) method Contents
123 to 134 Phase contrast Testing was performed
pjwder rco?, closet,
and nallway of a
privaCe hoaii.
220 to 232 Phase contrast Tiles, precoaled
with adhesive, were
installed in laundry
roon. powder rooa.
closet, and hallway
of a private bare.
and s*aall utility
room of private
hone.
10 Phase contrast Preparation include
stripping and dry
oopping uf old tile
surface.
sweeping occurred
during reaoval.
6} Phase contrast Self-ad>iering tiles
were installed
follouing stanaard
or^ proc^ wr«a.
ch«t !:3er Uvels
recorded rds_lted
during preceding
reooval operation.
60 to 132 Phase contrast rlouse'xeer.i.-B.B per-
for'icd, monitoring
conducted under
actual work
conditions.
let,
12
12
12
13
13
13
14
(continued)
-------
TABLE 27 (continued)
e&cos product
category
Asbestos produce Activity performed
Measured
fiber
concen-
tration
Dice of
teats
Duration of
activity/
sampling
tioe Analytical
(mm) method
CosBients
Bef.
asket^ i-iii packing Coinr^ssed asiieacos Scoraje for use
(continued) ine^c flange
gaskets
HanJ puncnug
Hand punching
Hand operated
Ddchanical punching
Machine punching
Machine punching
Machine punching
Hachine shearing
<0.01 co 1978 97 to 122 Phase contrast No control.11 Mont- 14
0.12 Coring conducted
ur«iir actual work
conditions.
3.00 1978 M Phase contrast ho control. Mom- 14
coring conducted
under actual work
conditions.
«O.OS to 1978 28 Co 31 Phase contrast Housekeeping. 14
0.15 • Monitoring conducted
condit 10 is.
<0.05 1978 30 Phase contrast No tontrul. Pom- 14
coring conduced
under actual work
conditions.
5.0 1978 - NR Phase contrast No control. Mom- 14
tonn£ ciniJucted
unJer actual tork
condit io.is.
<0.03 Co 1978 20 to 30 Phase contrast Housekeeping. I.
0.7 Monitoring cond^ctec
conditions.
<.O.OS to 1978 23 to 11 Phase contrast Housekeeping and 14
0.06 ventilation.1
Monitoring conducted
under actual vorA
conaitions.
••0.03 Co 1978 7 to 31 Phase contrast No control. Haiti.- 14
0.3 tonn£ coiduccec
under jciual work
conditions.
0.5 to 1978 6 Phase contrast No control. Mom- 14
1.3 coring conducted
under actual work
condicions.
O.Oi to 1978 31 to 38 Phase contrast Ho. > <• •..--. 14
0.15 Honitoring conducted
under actual work
condition!.
(continued)
-------
TABLE 27 (continued)
CaK^ury u^e.toi produce Activity performed
(continual sheet flange
gaskets
Machine nibbling
Installation of flange
gasket
installation (boiler
header gasket»)
Clean-up following reicoval
by hand scraping
Removal and nand scrapiag
Pojcr shear operdtian
He i»ured
fiber
concifn-
t r*t ion
(f/CQ3)
<0.08 to
0.46
O.OB co
0.8
<0.03
0.02 co
0.3
-0.05
-O.ub to
0.39
0.18
0.04 to
0.67
0.17
Duration of
act ivi ty/
•aopl ing
Date of Cine
tests (mm)
1978 8
1978 24 to 31
1978 30
1978 21 to 95
1978 33 to 37
1978 15 to 28
1978 25 co 33
1980 80 to 211
1980 188
Analytical
method
Phaae concrasc
Phase concraac
Phaae contrast
Phase contrasc
Phase concrasc
Phase contrast
Phase contrasc
Fibers were
counted by
phase concrast
with ?LM
verif icacioi
Fibers were
counted by
with FLH
verif Lcacion
Cocaents
No control. Moni-
toring conducted
under actual work
condicions.
Ho^st.i'.cip.ng.
under actual worn
condi t ions.
Ho cont ol. Moni-
toring onducted
under a tual woric
conditi ns.
Houstfk; pin^. Moni-
toring oaducted
under A tual work
cone it i >-5.
No control. Moni-
toring conducted
conditions.
No control. Moni-
toring conducted
ui drr actual born
cor Jit ions .
tor ing Lonjiicteu
und
-------
TABLE 27 (continued)
measured
fiber
coneen-
tralion
,i-acuct
Activity pLrforred
One of
tests
Duration of
ace ivity/
sampling
tin,:
(oin)
Analytical
=ethoJ
Coaaents
Cjskct-coapressud
JsJotos »heet
Shjjir ure..5 operation
Roussel press
Picking operation
Tun>ling operation
Material* handling
Platen preaE operation
Platen press operation
0.23 to
O.ol
0.04 to
0 08
0.10 to
0.31
O.ii co
O.oO
0.11 to
0.34
0.05 to
0.29
0.0} to
0.15
1980
1980
1980
1930
1980
1980
1980
63 to 238 Phase contrast
Hef.
50 10 76 filar, uerc Munitjruij p*rijr=ed IS
counted by at major ifsnat fab-
phase concrasc ricator located 10
with PLM Wisconsin.
verification
100 to 192 Fibers Wire Monitoring performed IS
coi.n:ed b/ at major Basket fab-
phjSk contrast ric£tjr l^c&hcd i:?
wiLh PU4 Ui»con*ln.
w«rification
93 to 206 Fioers wire Monitoring performed IS
counted by at icajor gasket fab-
phase contrast ricator located in
wich PLH Uiscoi.s.n.
verificatLon
77 to 141 Fiuk-r. WCTL Munt^r "., pcrf^r cc IS
c^un.«d by at .-jjor Oaai«et fao-
phisc Cwntrafit ric£ur locjidd in
uitu PLM Wisconsin.
verification
91 to 216 Fibers tore Monitoring p«frTjrud IS
counted by at najor gask.
-------
TABLE 27 (continued)
CJte j->
-ii>j?s:o-> produxt
Activity performed
Hea
fv
con
>t/
ured
Dale of
tests
OuritLon of
activity/
..Dpi ing
Clue
(mm)
Analytical
method
Coment*
= »et» jiJ pjc-iri Gasnet-coEpressed
CijaLinued) asbestos sheet
Pj:'r>iij - u*n.>n.ca
pac*ii£5 for ?uiV»
Hydraulic Dean press
Hand picking and packaging
PI iCen prc»a pil
operator
Reeves punch press
operator
Simulate*! Meld
installation
Sirjl^t^J recuval of
pjckin^ fcora puzip
j»itL> «na pJclM-12 Cuttin^/pai-kajing
0.02 to
0.05
0.06 co
O.-'O
O.09 Co
0.12
0.12
<0.1 to
0.1
•0.1 to
0.1
O.I to
0.5
(TWO
Nil
Phase contrast
(assuTed)
General fiber r£-.2es
are reported. *?K-
activities monit^rea
not available froa
r^ferrnee.
2ef.
1940 61 to 178 Phase contrast Monitoring perforae^ 16
using gasket oper-
1980 45 to 176 Phjse contrast .
-------
TABLE 27 (continued)
product
Activity pertoraed
Measured
fiber
concen-
tration
Dare of
tests
Duration of
activity/
sampling
Lime
(am)
Analytical
metnod
Ref.
Asp-a 11 and tjr-
3,*: j^-jp^l led
J»[> lu .1 1C COO.
Application
to
to
Asphalt-tf-j
Built-up roofing
Spraying
lojr-otE
Tear-off and replace
(»pray)
N'pu jp;>licaLion (spray)
coating by »puy
icacion
0 Zero release as 10
stated in cited
it not documented by
O.C03 Co 1974 342 to 432 Phase contrast Percer.t weight of 19
O.LS (acsumed) asbeccos as spra/«d
ranged from 5.8 to
7.7. after curing 9.7
to I*.o percisac
asbestos.
0.01 to 1974,1976 NR Phase contrast P^rc.rt weight, of 19
0.3 - (absuoed) asL>
-------
TABLE 27 (continued)
4j?est js ^roduwt
cjEo^ry Asbestos product Activity performed
(cjiu--«3f applications
Coating pipe interiors -
Fiber glass pipe MFC
(cunJrel coating)
Ship coaling below
filter! ino (spray
appl icat wi)
?j.rtl"i bullJl 1J
e.Lirior ( c Gen., r- i p 1 )
inLerior (cu-jnerciul)
Measured Duration of
fiber activity/
concen- sampling
tracioi Date of tine Analytical
(£/cm3) tests (coin) me chad
0.0 to 1974 11 to 38 Phase contrast
0.2 (assumed)
0.1 1974 }7 Phase contrast
(assumed)
0.1 to 147.* 14 to 23 Phase contrast
0.4 (assumed)
0.0 to 1974 21 to 65 Phase contrast
0.4 (assumed)
0.0 to 1974,1977 5 to 16 Phise ccncrast
0.06 (assuoid)
0.03 to 1977 23 Phase contrast
O.Oo (aasuned)
Conoencs
dock with an
asbestos-coma 11 ing
epojty and coal tar
asbestos a» sp-cxcil.
Operator sf-* :-„
interior j: 7.6, 13,
and 30 C-B dia=eter
pipes witn an
asbestos-containing
(I percent) epoxy
and coal tar mixture.
Operators noi.tored
were involvda in
running iuta-iatic
sp.ay t»a«.ii.~e bic.
wipn,- -ajnoie!. i
applied.
Cheitical resistant
prrcunt a»t«&C3s
appllcl!.
Alityi r.'ln ca-ct.n-
ing 6 perjenc s&bes-
C03 or vinyl-acrylic
latex containing 0.6
percent asb^stjs
appl lea.
Viryl-acry lie iatex
cantiin:r.6 O.o
percent asbestos
applied.
tut
19
19
19
19
19
19
(continued)
-------
TABLE 27 (continued)
»;us product
Activity
MedsureJ Duration of
fiber JCLiviLJ/
concea- saraplinj
traiion Dace of ciae
(f/c«3) te*ts (nin)
Analytical
nethod
Conncnts
let.
a3li"4S And h
(*.oii i no; J)
Resin coatings
Wall and roof spraying
Roof spraying
Boac MFC - spraying
surface coatings
pipe coac«!il with
Grinding FKP caiks and
pipe
Handsjnding interior
bjil-l-., panels
Sini olasELii^ hibh
p;rfor-5«TCe dxCi.Ti.or
-nit 1-1,1
0.0 to
0.2
0.0
L2 to 15
1974 U to 28
Phase contrast
(assuoed)
Operator spraying
2.S to J.7 percent
asbestos \ir>1 latex
on lerlical wall
pjoeI.
19
19
(a&»jDti(.) 0.7 pcrceiL asbcjcos
acrylic la;ex.
0.0 co 1972,1974, 4 to 55 Phase contrast Operator »pra>in« 19
0.6 1975 (assumed) 0.5 percent asbestos
general purpose
pal/ester ft.sin.
0.04 to 1973 19 to 49 Phase contrast Operaur is^in,- re- 19
0.1 (a»suned) inforc^J fioer ^lase
pipe coated uith
polyes:«r r^sin coa-
tai'iinj 2 CO 3 [»•=(•-
0.3 to 1974 5 to 25 Phase contrast Operator grinding 19
0.4 (assumed) fiber jlass reinfor-
ced plastic parts
• containing 1.5
asopstos.
0.0 to 1977 11 to 16 PhJse contrast Operntar handsanding 19
0.3 (aiiumea) pjn^l >uri.ces
c 5^-rrt.d * c •* vny 1
Idtax 131RL contain-
ing 1.1 percent
asbestos.
0.2 to 1978 5 to 27 Phase contrast Operators sandolasted 19
0.3 (assumed) L2 meter diameter by
7 6 R *;cr *iig*i steel
C4.I* s^ray Cvjcc- in
1973 with a 2.1 p«r-
(conei
-------
TABLE 27 (continued)
1 bl A L
(continued) gypsim-isied
drytill co-apould Mixing
(Study A) (dry powder)
Mixing
(pre-am)
HanJ bjnaing
Pole sanding
Sweeping
Sweeping
f ^->ajr.-bj->.-J (0.9 Co 1.5 m)
dry^all ccapound
(Study B)
Hand sanding
(0.9 to 1.5 m)
Pole sanding
(0.9 :- '. .*, c.)
Hea ured Duration of
fi ft activity/
con en~ saEpling
era ion Date of CIEE Analytical
III m1) tests .uin) method
1.3
9.0 to 1975-1977 10 to 12 Phase contrast
12.4
1.2 co 1978 4 CD i Phase contrast
i.2
2 1 co 1975-1977 10 co 80 Phase contrast
10.1
1.2 Co 1978 4 to 21 Phase contrast
10.0
4.0 co 1975-1977 9 to 30 Phase contrast
26.5
14.5 to 1978 10 Co 20 Phase contrast
25.4
59.0
16.9
1.2 to 1974 MR Phase contrasc
19.3
Consents
Residential setting.
Co'scier-ial operation.
Residential setting.
Commercial operation.
Residential setting.
Commercial operation.
is not less back-
ground Levels, which
for the Siime room
ranged from 0.5 to
13. I |'£«J.
is not Itfss uack-
ground levels, which
for the cane room
ranged froia 2.1 to
2.5 f/cn?.
Coraurcial operation.
is not less back-
ground Levels, which
Cor toe same room
ranged fro> 3.S Co
19. B f/ca3.
Rcf.
20
20
20
20
20
20
2L
21
(conCsvnued)
-------
TABLE 27 (continued)
Measured Duration o:
fiber activity/
comen- sampling
Aiaestoi 3 rod net trjtion Date of tine Analytical
catr,,o i p 1 p
(continue*!) gypcum-bj»tf J (3.0 to 15 o) (mean)
drywall compound
(Study 8>
sleeting
Score 3.2 1981 4 NIOSH Method
•I; .-_r 6. A, 1981 6,1 NIOSH Method
12.7
Sju 19). 8 1981 1 NIOSH Method
she citing in open air J 0.6 CO I960 NO Phase contrast
Grinding to cut sheeting ) 41
while oo roof
trti.k i lac sr.ee ting (asbuaed)
Sawing (13.3 outers) 0.0 1979-1980 40 Phase contrast
(assumed)
i
A .bt *tu.i-ccmcnc Sjwi-« with a circular 0.04 1979 12 Phase contrast
oownle
during sweeping,
•anpling occurred IS
Dilutee after sweep-
ing stopped. Att«r
35 oin^L«-s. the oca-
-cs 26.4 l/co3.
glove box.
Testing p«*rforDed in
glove box.
Based on two repet i-
tions in glove box.
Testing perforced in
glove box.
Testing perforated
on job aite.
with Jusc picnu^
bhroud.
Saw was equipped
with dust pickup
shroud that totally
enclosed oasoory
blade.
Saw was equipped
shroud that vented
to a Nilfisk HEPA
filtered vacuum
cleaner.
2
2
2
22
23
24
(continued)
-------
TABLE 27 (continued)
N>
CD
••"*UI' p y p
Asbesus-ievnt A>bestos-cccnp'ii>rute plint-
tuduccion furnace
Fircf L JIIL inj hel-nets.
be* *i*.-i,.c ith Navdl t iref ighcing
cloth cajvf h\.l'.cc.s
L.; !-..!-=[ ..(.i 1.. -jl :iref i^PiinK
clotl covtr heV~at.cs
ht.li^t wiEh alum- TidvjL firefighting
helmets
A.j^itOj jloves Future b.i, handling hoc
tray, C.j\in3 otf
Measured
fiber
conc^n-
trjiion Date of
(I/cm3) tests
0.15 1979
0.3-5.0 1975
(T.'A 0.1
CO 1.1)
9.9-26.2 1975
(TWA 6.7)
2.3 1971
1.38 1971
0 1971
0.95 to 1981
7.97
Duration of
activity/
saepl ing
cine Analytical
(oin) method
17 Phase contrast
52 Phase contrast
(average)
35 Phase contrast
(average)
20.6 Ptiabe contrast
20. 5 Phase contrast
<10 N1OSH Method
Comments
Power tools were
equipped with dust
pictu^ shrouds that
ve.it«£ co a Nilfisk
cleaner.
Actual sampling in
plant.
Actual sampling in
plant.
Range a: fiber levels
conitorcd in ventless
Isolation chacber
(glova box).
24
25
25
26
Zb
26
27
(conCLnued)
-------
TABLE 27 (continued)
M^a-.jred Duration ot
fiber activity/
cancan- i^mplirg
«- j*, »L*>» pr&J-ct l rat ion Dace of doe Analytical
category Asbc^t j« product *ci*vity performed (f/cra^) tests (am) method Cocnentc Ref.
Tr xi Ics Asbestos glovcb Putting on, handling hoc 0.07 to 19ol 10 N10SH Met nod Range of fiber level* 27
(burti JIM) tra> , tatting ^:L 0.99 ajnitorea in well
veitiUced b»olojy
pri.par dt ion rod ...
3dn{,.: «.TL^-I_>»«£
brtfiChin^ to le anJ
wurk jfca.
U»iu£ gloves in laboratory 0.04 to l^tl 10 K10SH Method Kan-e oc fibar level* 27
2 • 9 3 nan 1 1 or**d Uur 1*1^ nor~
mal use in university
labor a i dries*
File 0 ta 2.8 1981 3 Pnase contrast T^iting perfom^d in 2
glove bOA.
Drill 7.1 19B1 3 Phase contrast Testing perfomed in 2
glove box.
Grind 2.8 1961 "" Phase contract Testing performed in 2
glove box.
.1 -n_cru*LO| / cuuntini; fiber:. 3 _n long • s^ajin^ tnii existing £Luur covering or the residual Lclt, aid
t. - . i .ilj. i-^^i.tiM, iinolljiioii. dud [tfjivul witi.^ui Banding, u^e of a flat-bladed wall scraper instead of equipoAiL that
: i n..!^ ' ot i c lu Lilt ^n.l ii)i Lr dkiug me tilt by hjnd iff ore placing in a disposal bag.
« •_ - l' i i>.r", vjcui u 11 carers were used to clt-'an at«as. area Kept clean and free of debrii accumulation, waste cucerial placed in
^ j- t i*i, i.e.. no wett in^, enclosing, or ventilation.
ti'.h.
-------
Table 28 summarizes, by asbestos product type, the number of fiber
release monitoring studies that have been identified in this report. The data
have been compiled from the information provided in Table 27. Aa expected,
the majority of the studies have been performed on products that are suspected
to release high fiber levels based upon how they are acted upon and their
method of construction (e.g., asbestos-cement products and paper products), or
on products with widespread use such as friction products and floor tiles.
PRODUCT TESTING RECOMMENDATIONS
In accordance with the data reported, experimental limitations, and
reenactment equipment use limitations, asbestos-containing products are
prioritized for testing as follows:
• The following products are candidates for testing based on suspected
high fiber release potential, widespread application, and expected
future use:
- millboard
- commercial and household paper
flat asbestos-cement sheet
uncoated textiles
paper pipeline wrap.
• Products having low testing priority because (1) they have been
adequately examined, (2) the likelihood of harmful exposure during
use is low or (3) product distribution is limited are:
vinyl-asbestos floor tile
reinforced molded plastic components
asbestos-containing packings
petroleum-based surface coatings, sealants and adhesives
flooring felt
compressed sheet gaskets
coated textiles
beverage or pharmaceutical filters
asphalt-asbestos floor tiles
130
-------
TABLE 28. NUMERICAL SUMMARY OF MONITORING STUDIES PERFORMED ON
ASBESTOS-CONTAINING PRODUCTS3
Asbestos product category
Asbestos product
Number of studies
performed on product
as presented in this report
Asbestos-cement pipe
Asbestos paper
Friction products
Floor tile
Gaskets and packings
Coatings, bcslants, and
adhesives
Asbestos-cement sheets
Textiles
Reinforced pLas,tic
Water transfer pipe
Sewage transfer pipe
Other (electrical conduit,
chemical process piping)
Flooring felt
Roofing felt
Beater-add gaskets
Pipeline wrap
Millboard
Electrical insulation
Commercial papers
Specialty papers (e.g., tape)
Beverage and pharmaceutical
filters
Brake linings
Disc pads
Clutch facings
Other
Vinyl-asbestos tiles
Asphalt-asbestos tiles
Compressed sheet gaskets
Impregnated millboard
Impregnated yarn
Asphalt and tar-based
coatings and sealants
Latex or gypsum-based coatings
Adhesives
Roofing shingles
Siding shingles
Flat sheet
Corrugated sheet
Protective clothing
Firefighting helmets
Outer garments
Gloves
Tubing-wire and pipe insulation
Clutch-transmission components
Electrical insulators
Molded product components
for high strength/weight uses
2
0
1
0
5
0
4
0
2
2
0
0
0
3
I
aSonu- studies investigated fiber release from more than one product.
131
-------
Products Co be excluded from testing under this program iecause
their normal use activity is performed out of doors or with
specialized equipment which this project is not designed to obtain
nor operate are:
asbestos-cement pipe
asbestos-cement sheet (roofing shingles, siding shingles,
corrugated sheet)
friction materials
roofing felt.
132
-------
REFERENCES
1. Association of Asbestos Cement Pipe Producers, Recommended Standard for
Occupational Asbestos Exposure in Construction and Other Non-Fixed Work
Operations. Internal Report. Cosponsored by the Asbestos Information
Association of North America. February 1980.
2. Cogley, D., et al. The Experimental Determination of Asbestos Fiber Size
Distribution during Simulated Product Use. Prepared by CCA/Technology
Division for the U.S. Environmental Protection Agency, Office of
Pesticides and Toxic Substances, Washington, D.C. October 1981.
3. Roy, N., et al. Asbestos Product Test Results. Prepared by
GCA/Technology Division for the U.S. Environmental Protection Agency,
Office of Pesticides and Toxic Substances, February 1980.
4. Unilab Research, Berkeley, California, Asbestos Paper Product Testing
Results. Testing Performed for Channel 7 KGO TV, San Francisco, CA.
November/December 1979.
5. Wardley, F. L., President Quin-T Corporation-Electrical Insulation,
Written Correspondence to Mr. Richard Guimond, U.S. Environmental
Protection Agency, Office of Toxic Substances, Washington, D.C. October
30, 1980.
6. SRI International. Monitoring for Airborne Asbestos Fibers: Sheet Vinyl
Floor Covering. Prepared for Resilient Floor Covering Institute.
December 1979. SRI Project 7988.
7. SRI International. Comparison Testing Monitoring for Airborne Asbestos
Fibers: Sheet Vinyl Floor Covering, Wet Versus Dry Scraping. December
1979. SRI Project 7988.
8. Unpublished NIOSH Data Presented at American Industrial Hygiene
Conference, New Orleans, Louisiana. May 1977.
9. Rohl, A. N., et al. Asbestos Exposure During Brake Lining Maintenance
and Repair. Environmental Research, 12:110-128. 1976.
133
-------
10. Meylan, W. M., eC al. 1978. Chemical Market Input/Output Analysis of
Selected Chemical Substances to Assess Sources of Environmental
Contamination: Task III Asbestos. U.S. EPA Report Number
EPA-560/6-78-005.
11. Murphy, R. L., et al. Floor Tile Installation as a Source of Asbestos
Exposure. American Review of Respiratory Disease, Vol. 104. 1971.
12. SRI International. Monitoring for Airborne Asbestos Fibers: Vinyl
Asbestos Floor Tile. Prepared for Resilient Floor Covering Institute.
December 1979. SRI Project 7988.
13. SKI International. Comparison Testing Monitoring for Airborne Asbestos
Fibers: Vinyl Asbestos Floor Tile. Prepared for Resilient Floor
Covering Institute. December 1979. SRI Project 7988.
14. Liukonen, L. R., et al. Asbestos Exposure from Gasket Operations.
Report prepared by Industrial Hygiene Research, Naval Regional Medical
Center, Bremerton, Washington. May 1978.
15. Hager Laboratories, Inc. Report on Service Number 3910 for
Johns-Manville Corp. August 21, 1980. Published in Health and Safety
Facts: Mechanical Packings and Gasketing Materials Containing Asbestos
Fiber, Johns-Manville Corporation, Denver, Colorado.
16. Johns-Manville Corporation, Health, Safety, and Environment Department,
Industrial Hygiene Survey conducted July 1980 in Wisconsin. Results
published in Health and Safety Facts: Mechanical Packings and Gasketing
Materials Containing Asbestos Fiber, Johns-Manville Corporation, Denver,
Colorado.
17. Johns-Manville Corporation, Health, Safety, and Environment Department,
Industrial Hygiene Survey of Simulated Field Installation of
Asbestos-Containing Packings. Results of study published in Health and
Safety Facts: Mechanical Packings and Gasketing Materials Containing
Asbestos Fiber, Johns-Manville Corporation, Denver, Colorado.
18. Chapman, J. H., et al. Asbestos Dust; Technology Feasibility Assessment
and Economic Impact Analysis of the Proposed Federal Occupational
Standard: Part 1, U.S. Department of Labor, Occupational Safe.ty and
Health Administration.
19. Testimony Prepared for a Public Hearing Before the California
Occupational Safety and Health Standards Board. November 8, i978.
Source of testimony unknown. Information provided to GCA/Technology
Division by the Johns-Manville Corporation, Denver, Colorado.
20. Verma, D. K., and C. G. Middleton. Occupational Exposure to Asbestos in
the Drywall Taping Process. Presented in the Journal of American
Industrial Hygiene Association. Vol. 41. April 1980.
134
-------
21. Fischbein, A., et al. 1979. Drywall Construction and Asbestos
Exposure. J. American Industrial Hygiene Association, Vol. 40, pp.
402-407.
22. Rb'delsperger, K., et al. Estimation of Exposure to Asbestos-Cement Dust
on Building Sites. Study supported by the Umwelfbundesant, Berlin,
Project No. 10401023/11, by the Commission of the European Community,
Project No. 298-781 ENVD, and by the Bau-Berufsgenossenschaften,
Frankfurt.
23. Asbestos Information Association/North America. Recommended Work
Practice Procedures for Asbestos-Cement Sheet. Submittal to U.S.
Environmental Protection Agency, Office of Toxic Substances, in response
to Advance Notice of Proposed Rulemaking: Commercial and Industrial Use
of Asbestos Fibers. Docket Number OTS 61005.
24. Intra-Laboratory Memo, Argonne National Laboratory. Asbestos Fiber
Measurements During the Nilfisk Power Tool and Vacuum Demonstrai.ion,
Nilfisk of America Inc., King of Prussia, PA, December 7, 1981.
25. Gibbs, G. W. 1975. Fibre Release From Asbestos Garments. An.. Occup.
Hyg., Vol. 18, pp. 143-149.
26. Lumley, K. P. S. 1971. Asbestos Dust Levels Inside Firefighting Helmets
With Chrysotile Asbestos Covers. Ann. Occup. Hyg., Vol. 14, pp. 285-28I-.
27. Sami.ni, B. S., and A. M. Williams. 1981. Occupational Exposure to
Asbestos Fibers Resulting from Use of Asbestos Gloves. Am. Ind. Hyg.
Assoc. J. 42:870-875.
135
------- |