ALLIANCE
Technologies Corporation
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GCA-TR-CH-83-06
U.S. ENVIRONMENTAL PROTECTION AGENCY
Chemical Unit
Integrated Environmental Management Project
Office of Policy and Resource Management
Washington, DC 20460
Contract No. 68-02-3168
Task Nos. 54 and 96
EPA Task Manager
Arnie Edelman
PRELIMINARY ANALYSIS OF POSSIBLE
SUBSTITUTES FOR 1,1,1-TRICHLOROETHANE,
TETRACHLOROETHENE, DICHLOROMETHANE,
TETRACHLOROMETHANE, TRICHLOROETHENE,
AND TRICHLOROTRIFLUOROETHANE
Final Report
May 1983
Prepared by
Richard Rehm
Elizabeth Anderson
Samuel Duletsky
Terry 0'Brian
Hugh Rollins
GCA Corporation
GCA/Technology Division
Chapel Hill, North Carolina 27514
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This report was furnished to the U.S. Environmental Protection Agency by GCA
Corporation, GCA/Technology Division, in fulfillment of Contract No. 68-02-3168,
Task Order Nos. 54 and 96. The contents of the report do not necessarily
reflect the views and policies of the Environmental Protection Agency, nor
does mention of trade names or commercial products constitute endorsement or
recommendation for use.
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ABSTRACT
This document investigates the technical and economic feasibility of
substitution for six halogenated industrial solvents used in four source
categories. The solvents investigated are 1,1,1-trichloroethane,
tetrachloroethene (perchloroethylene), dichloromethane (methylene chloride),
tetrachloromethane (carbon tetrachloride), trichloroethene, and
trichlorotrifluoroethane (chlorofluorocarbon 113). The four source categories
investigated are metal cleaning, dry cleaning, surface coatings, and fabric
scouring.
The six halogenated solvents listed above are often used because their
physical and chemical properties make them unique in given situations. Thus,
it should be noted that substitution may not always be feasible. Substitution
should always be determined on a case-by-case basis.
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TABLE OF CONTENTS
LIST OF FIGURES ix
LIST OF TABLES x
1 .0 INTRODUCTION AND SUMMARY 1-1
1 .1 PURPOSE AND SCOPE 1-1
1 .2 METHODOLOGY 1-3
1.2.1 Description 1-3
1.2.2 Limitations 1-3
1.3 SUMMARY OF FINDINGS 1-4
1.3.1 Metal Cleaning 1-4
1.3.2 Dry Cleaning 1-6
1.3.3 Surface Coating 1-7
1.3.4 Fabric Scouring 1-8
1 .4 RECOMMENDATIONS FOR FUTURE STUDY 1-9
1.4.1 Metal Cleaning 1-10
1.4.2 Dry Cleaning 1-11
1.4.3 Surface Coating 1-11
1.4.4 Fabric Scouring 1-11
1.5 REFERENCES 1-12
2.0 METAL CLEANING 2-1
2.1 GENERAL DESCRIPTION OF USE 2-1
2.1.1 Industry Characterization 2-1
2.1.2 Process Description 2-2
2.2 SELECTION OF CLEANING METHODS 2-6
2.3 TECHNICAL ANALYSIS OF SUBSTITUTES 2-9
2.3.1 Aqueous Cleaning 2-9
2.3.1.1 Process Description 2-9
2.3.1.2 Method of Substitution 2-11
2.3.1.3 Degree of Substitution 2-13
2.3.1.4 Resource Availability 2-18
IV
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Table of Contents (con't.)
Page
2.3.2 Emulsion Cleaning 2-18
2.3.2.1 Process Description 2-18
2.3.2.2 Method of Substitution 2-19
2.3.2.3 Degree of Substitution 2-20
2.3.2.4 Resource Availability 2-23
2.3.3 Nonchemical Cleaning 2-23
2.3.3.1 Process Description 2-23
2.3.3.2 Method of Substitution 2-24
2.3.3.3 Degree of Substitution 2-24
2.3.3.4 Resource Availability 2-25
2.3.4 Cleaning with Other Organic Solvents 2-26
2.3.4.1 Process Description 2-26
2.3.4.2 Method of Substitution 2-26
2.3.4.3 Degree of Substitution 2-29
2.3.4.4 Resource Availability 2-34
2.4 ECONOMIC ANALYSIS OF SUBSTITUTES 2-34
2.4.1 Background 2-34
2.4.1.1 Industry Structure 2-35
2.4.1.2 Market Share of Substitutes 2-35
2.4.1.3 Growth Trends 2-38
2.4.2 Product Quality 2-41
2.4.2.1 Cold Cleaning with Halogenated Solvents
Versus Al ternati ves 2-41
2A.2.2 Vapor Degreasing Versus Alternatives 2-42
2.4.3 Capital and Annualized Operating Costs 2-43
2.4.3.1 Alternatives to Cold Cleaning With
Halogenated Solvents 2-43
2.4.3.2 Vapor Degreasing and Alternatives 2-44
2.5 CONCLUSIONS AND RECOMMENDATIONS 2-50
2.6 REFERENCES 2-53
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Table of Contents (con't.)
3.0 DRY CLEANING INDUSTRY 3-1
3.1 GENERAL DESCRIPTION OF USE 3-1
3.1.1 Process Description 3-1
3.1.2 Industry Characterization 3-2
3.2 DISCUSSION OF SUBSTITUTES 3-7
3.3 TECHNICAL ANALYSIS OF SUBSTITUTES 3-8
3.3.1 Method of Substitution 3-8
3.3.2 Impact of Fire Codes on Substitution 3-9
3.3.3 Degree of Substitution 3-11
3.3.4 Resource Availability 3-12
3.4 ECONOMIC ANALYSIS OF SUBSTITUTES 3-14
3.4.1 Product Quality 3-14
3.4.1.1 Cleanliness 3-16
3.4.1.2 Timeliness 3-16
3.4.1.3 Damage 3-16
3.4.2 Capital and Annualized Costs of Substitution 3-16
3.4.2.1 Model Plant Parameters 3-17
3.4.2.2 Capital Costs 3-17
3.4.2.3 Annualized Operating Costs 3-23
3.4.2.4 Costs of Fire and Boiling Code
Compliance 3-28
3.5 CONCLUSIONS 3-29
3.6 REFERENCES 3-30
4.0 SURFACE COATINGS 4-1
4.1 GENERAL DESCRIPTION OF SUBSTITUTES 4-1
4.2 TECHNICAL ANALYSIS OF SUBSTITUTES 4-2
4.2.1 Aerosol Paints 4-2
4.2.1.1 Substitutes 4-3
4.2.1.2 Effect of Solvent Substitution on
Product Quality 4-7
4.2.1.3 Resource Availability 4-7
vi
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Table of Contents (con't.)
Page
4.2.2 Traffic Paints 4-7
4.2.2.1 Substitutes 4-8
4.2.2.2 Effect of Substitutes on Product
Quality 4-8
4.2.2.3 Resource Availability 4-10
4.3 ECONOMIC ANALYSIS OF SUBSTITUTES 4-10
4.3.1 Industry Structure 4-10
4.3.2 Market Penetration of Substitutes 4-12
4.3.3 Industry Trends 4-12
4.3.4 Product Quality 4-15
4.3.5 Capital and Annualized Operating Costs 4-15
4.4 CONCLUSION 4-17
4.5 REFERENCES 4-20
5 .0 FABRIC SCOURING 5-1
5.1 GENERAL DESCRIPTION OF USE 5-1
5.1.1 Process Description 5-1
5.2 DESCRIPTION OF SUBSTITUTES 5-2
5.3 TECHNICAL ANALYSIS OF SUBSTITUTES 5-3
5.3.1 Method of Substitution 5-4
5.3.2 Degree of Substitution 5-4
5.3.3 Resource Availability 5-6
5.4 ECONOMIC ANALYSIS OF SUBSTITUTES 5-7
5.4.1 Industry Structure 5-7
5.4.2 Market Penetration of Substitutes 5-7
5.4.3 Growth Trends 5-11
5.4.4 Product Quality 5-11
5.4.5 Capital and Annualized Cost of Substitution 5-11
5.4.5.1 Model Plant Parameters 5-12
5.4.5.2 Capital Costs 5-12
5.4.5.3 Annualized Costs 5-12
5 .5 CONCLUSIONS 5-16
5 .6 REFERENCES 5-18
VI 1
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Table of Contents (con't.)
Page
APPENDIX A COMMENTS BY E.I. DU PONT DE NEMOURS AND COMPANY.. A-l
APPENSIX B COMMENTS BY THE HALOGENATED CLEANING SOLVENT
ASSOCIATION B-l
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LIST OF FIGURES
Page
FIGURE 2-1 MARKET SHARE OF METAL CLEANING TECHNIQUES 2-37
FIGURE 3-1 PERCHLOROETHYLENE DRY CLEANING PLANT FLOW
DIAGRAM 3-4
FIGURE 3-2 PETROLEUM SOLVENT DRY CLEANING PLANT FLOW
DIAGRAM 3-5
FIGURE 5-1 CONTINUOUS SOLVENT SCOURING RANGE 5-3
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LIST OF TABLES
TABLE 2-1 SOLVENT CONSUMPTION IN COLD CLEANING AND
VAPOR DECREASING, MG/YR
TABLE 2-2 ESTIMATED NUMBER OF ORGANIC SOLVENT CLEANERS
BY SIC CODE (1980)
TABLE 2-3 USE OF SOLVENT AND ALKALINE CLEANING SYSTEMS
BY SIC CODE, 1976
TABLE 2-4 COMMON METAL CLEANING SOLVENTS
TABLE 2-5 SUMMARY OF CERTAIN CALIFORNIA INDUSTRIES USING
SOLVENT CLEANING OPERATIONS
TABLE 2-6 NATIONAL DECREASING SOLVENT CONSUMPTION
TABLE 2-7 GROWTH TREND FOR DECREASING FOR SELECTED
INDUSTRY GROUPS
TABLE 2-8 COMPARISON OF COSTS FOR VAPOR DECREASING AND
ALKALINE WASHING ($)
TABLE 2-9 COMPARISON OF COSTS FOR CONVEYORIZED DECREASING
AND ALKALINE WASHING ($)
TABLE 2-10 COST COMPARISON BASED ON ACTUAL DATA: VAPOR
DECREASING VERSUS ALKALINE WASHING (Cost per
thousand square feet)
TABLE 2-11 COMPARISON OF COSTS FOR VAPOR DECREASING AND
EMULSION CLEANING ($)
TABLE 3-1 PHYSICAL PROPERTIES OF PETROLEUM DRY
CLEANING SOLVENTS
TABLE 3-2 ESTIMATED NUMBERS OF DRY CLEANING OPERATIONS
AND SOLVENT USAGE IN THE UNITED STATES
TABLE 3-3 SUMMARY OF MAJOR NFPA FIRE CODE RECOMMENDATIONS
FOR THREE TYPES OF DRY CLEANING PLANTS
TABLE 3-4 ESTIMATED U.S. PRODUCTION CAPACITY FOR
PETROLEUM DRY CLEANING EQUIPMENT ,
TABLE 3-5 PERCHLOROETHYLENE MODEL PLANT PARAMETERS
Page
2-3
2-4
2-14
2-31
2-36
2-39
2-40
2-45
2-46
2-48
2-49
3-3
3-6
3-10
3-15
3-18
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List of Tables (con't.)
TABLE 3-6 PETROLEUM MODEL PLANT PARAMETERS
TABLE 3-7 CAPITAL COSTS FOR CONVERTING A SMALL
COMMERCIAL MODEL PLANT TO PETROLEUM SOLVENT
TABLE 3-8 CAPITAL COST OF CONVERTING A LARGE COMMERCIAL
MODEL PLANT TO PETROLEUM SOLVENT
TABLE 3-9 CAPITAL COSTS FOR CONVERTING AN INDUSTRIAL MODEL
PLANT TO PETROLEUM SOLVENT
TABLE 3-10 COMPARATIVE ANNUALIZED OPERATING COSTS OF USING
PETROLEUM SOLVENT AND PERC IN A SMALL COMMERCIAL
MODEL PLANT
TABLE 3-11 COMPARATIVE ANNUALIZED OPERATING COSTS OF USING
PETROLEUM SOLVENT AND PERC IN A LARGE COMMERCIAL
MODEL PLANT
TABLE 3-12 COMPARATIVE ANNUALIZED OPERATING COSTS OF USING
PETROLEUM SOLVENT AND PERC IN AN INDUSTRIAL
MODEL PALNT
TABLE 4-1 POTENTIAL SOLVENT SUBSTITUTES FOR METHYLENE
CHLORIDE IN AEROSOL PAINTS
TABLE 4-2 POTENTIAL SOLVENT SUBSTITUTES IN TRAFFIC PAINT...
TABLE 4-3 1979 PRODUCTION OF SURFACE COATINGS
TABLE 4-4 1980 PROFILE: PAINTS AND ALLIED PRODUCTS
TABLE 4-5 GEOGRAPHICAL DISTRIBUTION OF PAINT PLANTS
TABLE 4-6 PAINTS AND ALLIED PRODUCTS: TRENDS AND
PROJECTIONS 1975-81
TABLE 4-7 PRICES OF SOLVENTS
TABLE 5-1 EXAMPLES OF OIL REMOVAL EFFICIENCIES FOR CFC-113.
TABLE 5-2 KNIT FABRIC MILLS: TRENDS AND PROJECTIONS
1975-80
Page
3-19
3-20
3-21
3-22
3-25
3-26
3-27
4-5
4-9
4-11
4-13
4-14
4-16
4-18
5-5
5-8
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List of Tables (con't.)
TABLE 5-3 GEOGRAPHICAL DISTRIBUTION OF WET PROCESSING
TABLE 5-4
TABLE 5-5
TABLE 5-6
TABLE 5-7
TEXTILE MILLS
PRODUCTION CAPACITY OF PROCESSING MILLS ,
CAPITAL COSTS FOR CONTINUOUS AQUEOUS
SCOURING FACILITY
COMPARATIVE ANNUALIZED COSTS OF CONTINUOUS
AQUEOUS AND SOLVENT SCOURING ,
COMPARATIVE ANNUALIZED COSTS OF CONTINUOUS
AQUEOUS AND SOLVENT SCOURING
5-9
5-10
5-13
5-14
5-15
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ACKNOWLEDGMENT
The authors wish to gratefully acknowledge Ms. Virginia Steiner of
EPA's Office of Solid Waste, Mr. Arnie Edelman of EPA's Integrated
Environmental Management Project, Ms. Margo Og6 of EPA's Office of Toxic
Substances, and Mr. David Patrick of EPA's Office of Air Quality Planning
and Standards for their extensive review, comments, and technical advice
during each stage in the development of this document.
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1.0 INTRODUCTION AND SUMMARY
1.1 PURPOSE AND SCOPE
This report presents a preliminary analysis of the technical and
economic feasibility of substituting various chemical compounds and
physical processes for six halogenated compounds: trichloroethene;
tetrachloroethene (perchloroethylene); dichloromethane (methylene
chloride); 1,1,1-trichloroethane (methyl chloroform); tetrachloromethane
(carbon tetrachloride); and 1,1,2-trichloro-l,2,2-trifluoroethane
(CFC-113). These six were chosen for study because the Environmental
Protection Agency (EPA), as well as other Federal regulatory agencies,
have developed, or are in the process of developing, regulations that
directly or indirectly impact these solvents. Because these regulations
result from different statutory authorities exercized by different
agencies, there exists the potential for conflict, overlap and/or
gaps among the regulatory actions.
The purpose of this report is to provide the Environmental Protection
Agency with preliminary information concerning the substitution of
various other chemicals and physical processes for the six halogenated
solvents in order to assist in the conduct of the regulatory analysis.
This report identifies potential substitutes for these solvents and
presents a preliminary analysis of relevant technical and economic
issues. This report should not be considered a complete substitutes
analysis for two reasons: first, it evaluates neither the health
effects of the halogenated solvents nor the substitutes identified.
For example, certain aromatic, aliphatic, and oxygenated solvents were
identified as potential substitutes in certain situations. These
solvents are photochemically reactive. The potential increase in ozone
concentrations versus the potential decrease in halogenated solvent
concentrations was not investigated. Second, although the substitutes
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analysis addresses the capital and annualized costs of substitution to
the user, it does not address the user's ability to pay the costs of
substitution. A complete economic analysis would need to address this,
as well as the costs to producers of the halogenated solvents,
substitutes, and their distributors. It should be stressed that
although several substitutes have been identified, they may not be
applicable in every situation. Applicability must be determined on a
case-by-case basis.
In accordance with EPA Order 2200, this report has been distributed
for external review and comment. Of the approximately 100 copies
distributed for review, only 2 commenters responded: E.I. du Pont
de Nemours and Company (DuPont), and the Halogenated Cleaning Solvent
Association (HCSA). Comments made by DuPont and HCSA can be found in
Appendices A and B of this document respectively.
The substitutes analysis focuses on four industrial use categories:
metal cleaning, dry cleaning, paint formulation, and fabric scouring.
These source categories were chosen following a screening study in
which all categories that use the halogenated solvents were investigated.
Metal cleaning, dry cleaning, paint formulation, and fabric scouring
were chosen because the screening study showed that substitution in
these categories was feasible. In addition, metal cleaning and dry
cleaning use more of the halogenated solvents than any other use category.
Although the six halogenated solvents investigated have many of
the same properties, such as good solvency, nonflammability, and high
vapor density, they are not completely interchangeable. Thus, some of
the substitutes that are mentioned may not be suitable for all of the
solvents in certain situations. This particularly true for CFC-113.
This solvent is approximately four times more expensive than the other
halogenated solvents, and is often used when nothing else will do the
job adequately. It's low boiling point, mild solvent properties, and
low toxicity make it advantageous in the electronics industry where
extremely low levels of residues and soil are essential to the product's
end-use and reliability.
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1.2 METHODOLOGY
1.2.1 Description
The solvent substitute feasibility analysis presented in this report
is in the form of a screening study. First, a comprehensive list of
possible substitutes was compiled for each industrial use category. These
were then screened, based on technical performance, general availability,
and relative cost, to identify those with the most likelihood for use.
That group was then subjected to more detailed technical and economic
feasibility analyses to assess the probability of use.
1 .2.2 Limitations
The user of information in this screening study should be aware of
the limitations of the findings. First, the scope of this effort,
precluded a complete analysis of the technical and economic feasiblity of
substitution. By its very nature, the feasibility of substitution is a
complex subject. From a technical perspective, substitution for solvents
in a given use category can range from being relatively straightforward to
very complex. For example, petroleum solvents under certain circumstances
and restrictions can serve as a good technical substitute for
perchloroethylene in dry cleaning operations. However, in metal cleaning
operations, the number and the type of substitutes for solvents is large
and the technical performance varies from application to application. In
certain instances, there are no substitutes for halogenatec1 solvents. For
example, aqueous cleaning can substitute effectively for vapor degreasing
in cleaning automotive transmissions gears; however for cleaning many
kinds of electronic assemblies only certain halogenated solvents will do
the job adequately. Also, there are huge data gaps with respect to
technical performance of substitutes. In metal cleaning this results
because the use category is not a single industry but a process used in
thousands of different industries.
From an economic standpoint this report addresses only the issue of
the cost of substitution of the user. A complete economic analysis would
also need to assess the costs incurred by other affected parties due to an
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increased level of substitute usage. These affected parties would include
the manufacturers of substitutes; solvent producers; solvent and substitute
distributors; and consumers. Some of these affected parties would
experience a decrease in demand for their products and services while
others would benefit from the shift in demand towards their sector.
Producers of halogenated solvents would experience a decline in sales of
their product while producers of substitute compounds would enjoy an
increase in sales. Consumers may be forced to finance much of the costs
of solvent substitution in the form of higher prices for goods formerly
processed by a solvent system.
The type of regulatory action being considered would determine the
scope of any complete economic impact analysis. For example, if substitution
increases because a regulation limits production of the chemical of
concern, the economic feasibility of substitution cannot be determined
without data on the manufacturers of the substituted product, e.g. excess
capacity, ability to finance increased production, and the price
elasticity of the demand for the substitute. The above factors will affect
the price of the substitute, which in turn affects the costs of the
substitute to the users.
Definitive conclusions on substitution cannot yet be reached for all
potential users in all industries. In this report, estimates of user's
costs were confined to increased capital and annual operating costs.
Extensive data gaps need to be filled before the probable economic effects
of a regulatory policy which would encourage substitution away from the
chemicals of concern could be predicted. Identifying specific regulatory
alternatives is an essential element in the development of the proper
analytical methodology for filling these data gaps.
1 .3 SUMMARY OF FINDINGS
1.3.1 Metal Cleaning
Trichloroethylene, perchloroethylene, 1,1,1-trichloroethane, methylene
chloride, and trichlorotrifluoroethane are presently used in metal cleaning
because their unique physical properties make them advantageous in many
instances in comparison with other metal cleaning methods. Their solvent
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power, vapor density, vapor pressure, boiling range, and nonflammability,
in conjunction with the nonphotochemical reactivity of some make them
attractive as metal cleaning solvents. For substitutes to be effective,
they must be able to remove soils as safely and effectively as halogenated
solvents and at comparable cost.
Probable substitutes to metal cleaning with trichloroethylene,
perchloroethylene, methylene chloride, 1,1,1-trichloroethane, and
trichlorotrifluoroethane can be broken down into four separate subcategories:
aqueous cleaning, emulsion cleaning, nonchemical cleaning, and cleaning
with other organic solvents.
Aqueous cleaning describes a wide range of water-based cleaning
methods which use combinations of either acidic or alkaline compounds
to displace soils rather than dissolving them in an organic solvent.
Emulsion cleaning describes those cleaning techniques which remove
soils by the use of common organic solvents such as mineral spirits,
which are dispersed as fine droplets in an aqueous medium with the aid
of an emulsifying agent. Nonchemical cleaning techniques principally
rely on the use of mechanical energy as opposed to chemical or aqueous
media to remove soil. The nonchemical cleaning technique examined in
this analysis is abrasive blasting with materials such as aluminum
oxide, silica sand, and glass beads. Metal cleaning with other organic
solvents describes those processes that use aromatic, aliphatic, oxygenated,
and other halogenated solvents.
Based on general cost comparisons, relative ability to meet production
volume requirements, and product quality considerations, aqueous cleaning
is a viable substitute cleaning method for many metal cleaning operations
currently using solvents (see Section 2.3.1). Its principal disadvantages
are that the materials are wet after cleaning and ferrous metals rust
in aqueous environments. However, technological innovation on the part
of aqueous cleaning equipment and cleaning compound manufacturers is
anticipated to increase both the technical and economic parity of this
substitute method with solvent metal cleaning.
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Substitution with other organic solvents, such as mineral spirits,
also appears to be a viable alternative to cleaning with the six halogenated
solvents in certain cases (see Section 2.3.4). This is a particularly
valid substitute for many maintenance and repair operations using room
temperature cleaning because no new equipment would need to be purchased
and installed. The disadvantage of other organic solvents is that
most, if not all, are flammable. One halogenated solvent, trichlorofluoro-
methane (CFC-11), has been identified as a technological substitute to
trichloroethylene, 1,1 ,1-trichloroethane, methylene chloride, and
trichlorotrifluoroethane (CFC-113) as a vapor degreasing agent for
solvent metal cleaning. Its physical properties and solvent characteristics
are compatible with use in modified existing vapor degreasing equipment.
However, CFC-11 is regulated under the Toxic Substances Control Act as
an aerosol propel 1 ant because of its potential to damage the stratospheric
2
ozone layer.
The method which seems to possess the smallest degree of substitutability
for either cold cleaning or vapor degreasing is abrasive blasting
(Section 2.3.3). Abrasive blasting generally is not capable of meeting
the same product quality standards other than for items with no surface
finish requirements. In addition, it cannot be adapted readily for use
on objects with complex shapes or internal passages.
1 .3.2 Dry Cleaning
Dry cleaning is a process for cleaning clothes with organic solvents
instead of detergent and water. Perch!oroethylene and/or trichlorotri-
fluoroethane (CFC-113) are used in coin-operated cleaners and in certain
industrial and commercial facilities. They are used because of their
excellent solvent properties, gentle cleaning characteristics, non-
flammability, and compatability with all types of dry cleaning equipment.
Petroleum solvents are also used by the dry cleaning industry and
are the only commercially available substitutes (see Section 3.1).
Although they are used primarily by industrial cleaners, they can be
used in the commercial sector. They cannot be used by the coin-operated
sector because of flammability. Petroleum solvents are mixtures of
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paraffins and aromatic hydrocarbons similar to kerosene. Petroleum
solvents are comparable to perchloroethylene and CFC-113 in their
ability to clean soiled articles. The equipment used to dry clean with
petroleum solvents is similar to the equipment used to clean with
perchloroethylene and CFC-113. However, because petroleum solvents are
combustible, new dry cleaning equipment specifically designed for
petroleum solvents must be installed to replace equipment designed for
perchloroethylene and CFC-113.
While petroleum solvents commonly are used in dry cleaning, local
fire codes may prohibit large scale substitution to these solvents. The
fire codes for combustible solvents, such as petroleum solvents, include
special fire-resistant construction of the building, special wiring, a
sprinkler system, and a special heating system for the building. In many
cases, depending on the building type, location, size, and ownership, a
dry cleaner may be unable to make the structural changes necessary to meet
the requirements of fire codes. Also, fire codes in some areas make
substituting petroleum solvents for nonflammable solvents illegal. The
constraints placed on dry cleaners by fire codes and the associated costs
of retrofitting facilities make substitution for perchloroethylene and
CFC-113 dry cleaners infeasible for many existing establishments.
1.3.3 Surface Coating
The three major types of surface coatings are paints, lacquers, and
finishes. These surface coatings are grouped into three main use categories
architectural paints, product finishes, and special purpose coatings.
Surface coatings have a variety of uses including decoration, weather and
chemical protection, and safety marking.
Surface coatings are typically composed of three components: a
binder, a pigment system, and a solvent. Historically, the solvents first
used in surface coating were wood chemicals. Later, simple petroleum
derivatives (aliphatics and aromatics) began to find greater use. Both
wood and petroleum solvents enjoyed low cost and were readily available.
In later years, other types of solvents made inroads in specialty areas.
Today, available literature and industry sources indicate that chlorinated
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solvents are used primarily in special purpose coatings for two types of
products: aerosol paints and traffic paints. However, because of
their high cost, chlorinated solvents account for only a small percentage
of all solvents used in surface coating applications (see Section 4.1).
One industry source estimates that methylene chloride accounts for only
about 0.4 percent of all solvents used annually in all surface coatings.
Likewise, 1 ,1 ,1-trichloroethane accounts for only about 7.5 percent and
methylene chloride accounts for only 1.6 percent of all solvents used
in traffic paints.
Because 1,1,1-trichloroethane and methylene chloride are not
photochemically reactive, they are being marketed aggressively as
substitutes for various aliphatic and aromatic solvents presently used
in surface coating operations. Thus, the amount of 1,1,1-trichloroethane
and methylene chloride used in traffic paints and aerosol paints may
actually increase. Use of 1,1,1-trichloroethane and methylene chloride
may expand to other surface coating operations including architectural
coatings and product finishes. This report does not examine the potential
impact of this phenomenon. Rather, it only examines the practicality
of replacing chlorinated solvents with conventional solvents. Potential
substitutes for chlorinated solvents are wood and petroleum solvents.
The most common substitutes for the chlorinated solvents are acetone,
methyl ethyl ketone, toluene, and hexane. The use of these substitute
solvents for methylene chloride and 1,1,1-trichloroethane should not
have a significant effect on the product quality of most reformulated
aerosol paints or traffic paints. However, one industry source estimates
that about 10 percent of aerosol paint formulations could not be reformulated
to use a solvent other than methylene chloride.
1.3.4 Fabric Scouring
Fabric scouring is the process for cleaning textile fibers or
fabrics during their manufacture. Fabric scouring can be performed
using either aqueous or solvent media. In aqueous scouring, an aqueous-based
solution containing alkali reagents and anionic or nonionic surfactants
is used. Fabric scouring may be performed in a batch or continuous
process with the continuous process being used most often.
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Solvent scouring currently is used primarily for the cleaning of
synthetic knit goods prior to finishing. Solvents are effective at
removing the knitting oils applied to yarns to facilitate knitting.
Solvents are not as effective in removing the chemicals that are used
in making woven goods; therefore, solvent scouring generally is limited
to the knit fabric segment of the textile industry.
Perchloroethylene is a solvent frequently used in scouring.
Trichloroethylene is also used, and recently trichlorotrifluoroethane
has come into use. Several other organic solvents, such-as benzene,
xylene, petroleum solvents, and 1,1-dichloroethylene, have been reported
as potential substitutes although none are presently known to be used
in fabric scouring, and information concerning their technical and
economic feasibility as substitute solvents is not available.
1 .4 RECOMMENDATIONS FOR FUTURE STUDY
Future study of solvent substitutes depends on the regulatory
impetus for solvent substitution. Regulation of solvents can be direct,
such as a production cap; or indirect, such as controlling indicator
substances like volatile organic compounds. The technical and economic
feasibility of substitution would likely differ depending upon which
scenario is in place.
If direct control strategies are studied, then the study effort
must include solvent producers, solvent/substitute users, and substitute
producers. The interaction of all markets must be considered to understand
the technical and economic dynamics of substitution. If production of
a specific solvent is limited artifically (in terms of free markets)
due to regulation, then it would be important to understand the effects
this reduced demand would have on the solvent manufacturer and the
associated channels of distribution. Likewise, the reduced demand for
solvents would cause an increased demand for substitutes. For both
solvent and substitute producers the following need to be addressed:
1-9
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• Potential price changes for intermediate and final products.
• Potential impacts on profitability of discrete chemical
operations.
• Potential changes in employment in producing industry.
• Potential changes in capacity and production.
• Potential changes in sales and jobs within the distribution
network.
In order to evaluate the above items, detailed historical information is
needed on total capacity, capacity utilization, sales, profits, prices
and end uses. In addition, both the fixed and variable costs of production
need to be identified for each segment of the industries being analyzed.
It is desirable to evaluate the relationship between the solvent and
solvent substitute producing industries.
Indirect control strategies might require much of the same study,
but because it is not likely that solvent demand would be reduced with an
indirect control strategy, less emphasis could be placed on solvent
manufacturers and more placed on technical and economic feasiblity for
solvent/substitute users and substitute producers. Under this scenario,
the information contained in this report becomes important in shaping
future study needs.
Following are some recommendations for future study for three of
the four user categories studied in this report.
1.4.1 Metal Cleaning
Additional study in this area needs to be undertaken before definitive
conclusions can be drawn about the technical and economic feasibility of
substitutes for solvents. For example, this preliminary analysis
attempted to measure economic feasibility in terms of the capital and
annualized operating costs of substitutes. However, the only comparative
data found were dated. The scope of past studies has been to compare
cost and technical compatibility on a one-to-one replacement basis
(e.g., aqueous washing systems versus open top vapor degreasers). With
1-10
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changing technology, utility costs, and solvent prices, it is not known
if the specific examples cited in this report can be extrapolated to
other industrial categories. Thus, a specific methodology, perhaps in
the form of an economic model, should be devised to perform economic
analyses using current price and cost parameters. Additionally, more
work needs to be conducted to determine current usage of solvents
versus substitutes.
1.4.2 Dry Cleaning
Although substitution of petroleum solvents for perchloroethylene and
CFC-113 is possible on a technical and cost basis, the economics of
retrofitting to meet fire codes was not investigated. Prior to this,
fire codes need to be reviewed to determine how many areas would allow
petroleum solvent substitution. Likewise, commercial and industrial
cleaners should be surveyed to determine how many could substitute at
their present location.
1.4.3 Surface Coating
Because certain chlorinated solvents are not photochemically reactive,
solvent producers are making a concerted effort to increase sales of
chlorinated solvents to paint formulators. Little data are available
concerning the potential increase in the use of nonphotochemically reactive
solvents in the surface coatings industry. Study is also needed
on the health and environmental impacts such substitution may have.
1.4.4 Fabric Scouring
A preliminary model plant analysis was used to estimate capital and
annualized operating costs of substituting aqueous scouring for solvent
scouring. To complete a more detailed analysis, the parameters of the
model plants (used in developing cost estimates) need to be examined for
relevance in today's market. Also, it would be useful to know the number
of mills using aqueous vs. solvent systems, a better estimate of product
quality differences between the two, and the extent to which drying vs.
nondrying procedures are implemented when aqueous systems are used.
1-11
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1.5 REFERENCES
1. U.S. Environmental Protection Agency. Materials Balance Summaries
for Trichloroethylene, Perchloroethylene, 1,1,1-Trichloroethane,
Methylene Chloride, and Trichlorotrifluoroethane. Office of
Toxics Integration. Washington, DC. August 1981.
2. U.S. Environmental Protection Agency. Prohibition of Manufacturing,
Processing, and Distribution in Commerce of Fully Halogenated
Chlorofluoroalkanes for Aerosol Propellant Uses. 40 CFR 712, 762.
Office of Toxic Substances. March 17, 1978.
1-12
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2.0 METAL CLEANING
2.1 GENERAL DESCRIPTION OF USE
2.1.1 Industry Characterization
Metal cleaning does not constitute a distinct industrial category but
rather is an integral processing operation used in the manufacturing, main-
tenance, and repair of virtually all metal based commodities. Trichloro-
ethylene, perchloroethylene, methylene chloride, 1,1,1-trichloroethane, and
trichlorotrifluoroethane are widely employed in manufacturing applications as
cleaning agents to facilitate the removal of drawing compounds, cutting
fluids, coolants and lubricants. Typically, such metal working compounds
possess a grease or oil base which is removed by the action of one or more of
the solvents listed above. These solvents are also used in maintenance and
repair applications to remove similar contaminants prior to inspection,
machining, rebuilding, and assembly.
Trichloroethylene, perchloroethylene, methylene chloride,
1,1,1-trichloroethane, and trichlorotrifluoroethane are widely used in metal
cleaning because they exhibit excellent solvency for most industrial
contaminants, have rapid evaporation rates, are chemically compatible with most
metals, and are nonflammable. Carbon tetrachloride, although once a popularly
used metal cleaning solvent, is no longer used for that purpose because of
its relatively high toxicity.
Metal cleaning is used in a large number of manufacturing sectors and
several service sectors (maintenance and repair activities) within the economy.
Manufacturing industries which use metal cleaning are included within the
following two-digit Standard Industrial Classification (SIC) code sectors:
25 (Metal Furniture), 33 (Primary Metals), 34 (Fabricated Products), 35
(Nonelectric Machinery), 36 (Electric Equipment), 37 (Transportation Equipment),
38 (Instruments and Clocks), and 39 (Miscellaneous Industry). Service sectors
which do metal cleaning include: 401 (Railroads-maintenance), 458 (Air Transport-
maintenance), and 758 (Auto Repair).
2-1
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As noted, the industries which use metal cleaning vary substantially.
Metal cleaning occurs in large manufacturing operations employing thousands
of people and in small repair shops employing few people. There is no
direct connection between the size of an operation and the amount of
metal cleaning done in any particular industry. In addition it should be
noted that not all plants within the SIC codes listed above do solvent
metal cleaning. Estimates range from a low of 39 percent for SIC 39
(Miscellaneous Industry), to a high of 65 percent for SIC 38 (Instruments
and Clocks).
Solvent cleaning may be divided into two categories based on the
temperature of the solvent employed: cold cleaning and vapor degreasing.
In cold cleaning operations, both halogenated and nonhalogenated solvents
are used depending upon the nature of the particular application. Vapor
degreasing operations, however, require the use of halogenated solvents
(i.e. trichloroethylene, perchloroethylene, methylene chloride, 1,1,1-
trichloroethane, and trichlorotrifluoroethane) due to their unique
physical properties of possessing nonflammable vapors that are heavier
than air. Table 2-1 lists the distribution of these solvents in cold
cleaning and vapor degreasing based on information provided by the Office
of Toxics Integration, while Table 2-2 lists the estimated number of cold
cleaners, open top vapor degreasers and conveyorized degreasers by SIC
code in 1980.
Cleaning with halogenated and nonhalogenated solvents is commonplace
in maintenance industries such as automotive, railroad, bus, aircraft,
truck and electric tool repair facilities. Many of these businesses use
trichloroethylene, perchloroethylene, methylene chloride, 1,1,1-trichloroethane,
and trichlorotrifluoroethane at least occasionally, if not on a regular
basis.
2.1.2 Process Description
Cold cleaning operations use solvent at or near ambient temperature.
The solvent chosen may be heated but always remains well below its boiling
point. This class of solvent cleaning ranges in sophistication from
simple handwiping with a solvent-soaked cloth or sponge to the use of
extensively engineered machinery which clean parts by spraying, flushing,
2-2
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TABLE 2-1. SOLVENT CONSUMPTION IN COLD CLEANING AND VAPOR
DECREASING, MG/YR (1980)1
Trichloroethylene
Perchloroethylene
1 ,1 ,1-Trichloroethane
Methyl ene Chloride
Tr i chl orotri f 1 uoroethane
Cold
cleaning
25,000
15,600
106,600
40,100
9,100
Vapor
degreasing
85,000
38,300
80,400
12,200
38,900
Total
110,000
53,900
187,000
52,300
48,000
2-3
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TABLE 2-2. ESTIMATED NUMBER OF ORGANIC SOLVENT CLEANERS BY SIC CODE (1980)'
Standard
industrial
classification
(SIC)
25
254
259
33
332
335
336
339
34
342
343
344
345
346
347
348
349
35
351
352
353
354
355
356
357
358
359
36
361
362
364
366
367
369
37
371
372
376
379
38
381
382
39
401
458
753
Industry
Metal Furniture
Partitions and Fixtures
Miscellaneous Furniture and Fixtures
Primary Metals
Iron and Steel Foundries
Nonferrous Rolling and Drawing
Nonferrous Foundries
Miscellaneous Primary Metal Products
Fabricated Products
Cutlery, Hand Tools and Hardware
Plumbing, and Heating (Nonelectric)
Fabricated Structural Metal Products
Screw Machine Products, Bolts, etc.
Metal Forgings and Stampings
Metal Services
Ordnance and Accessories
Miscellaneous Fabricated Metal Products
Nonelectric Machinery
Engines and Turbines
Farm and Garden Machinery
Construction and Related Machinery
Metalworking Machinery
Special Industry Machinery
General Industry Machinery
Office and Computing Machinery
Refrigeration and Service Machinery
Miscellaneous Machinery (Nonelectric)
Electric Equipment
Electric Distributing Equipment
Electrical Industrial Apparatus
Electric Lighting and Wiring Equipment
Communication Equipment
Electronic Components and Accessories
Miscellaneous Electrical Equipment
and Supplies
Transportation Equipment
Motor Vehicles and Equipment
Aircraft and Parts
Guided Missiles, Space Vehicles, Parts
Miscellaneous Transportation Equipment
Instruments and Clocks
Engineering and Scientific Instruments
Measuring and Controlling Devices
Miscellaneous Industry
Rail roads -Maintenance
Air Transport-Maintenance
Auto Repair
No. of
plants
3,710
2,095
1,932
1,596
3,714
1,265
4,238
2,277
19,172
3,263
5,427
6,611
467
8,670
576
3,428
6,151
16,729
7,282
8,171
2,756
3,630
28,807
1,646
3,001
3,616
4,647
7,453
2,815
6,533
2,120
128
2,684
1,550
4,501
31,723
1,196
4,512
115,591
No. of
cold
cleaners
7,165
3,800
4,759
2,226
4.020
9,626
13,716
2,759
32,604
3,861
7,612
21,591
148
18,058
916
10,322
13,383
48,446
11,820
38,249
7,371
7,128
98,290
4,652
4,748
11,907
13,496
13,577
6,357
13,041
14,070
841
4,606
7,423
21,704
19,997
1,267
48,832
518,633
No. of
open top
vapor
degreasers
467
145
374
314
119
1,420
1,518
233
1,145
130
303
1,447
6
1,112
44
435
622
825
53
2,66*
404
226
1,532
1,174
366
3,066
3,452
2,072
103
857
3,733
239
0
766
4,450
880
84
5,020
0
No. of
conveyorized
degreasers
133
41
79
68
24
303
316
48
237
27
63
301
1
230
7
80
113
151
10
489
74
40
280
133
40
345
387
232
12
104
452
29
0
38
223
90
0
0
0
TOTAL
335,783
1,073,079
41,800
5,200
2-4
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or ultrasonically agitating the solvent. The type of cold cleaning
technique and solvent to be used in a given application depends upon a
number of variables such as: size and shape of parts to be cleaned, type
of contaminant to be removed, the degree of cleanliness required, and •
solvent cost.
While there exist a number of different vapor degreasing designs of
various sizes, all have three fundamental structural features in common: a
tank to contain the solvent and solvent vapors, a heating system with which
to boil the solvent, and a cooling system used to control the diffusion of
solvent vapors from the tank. The solvent is raised to its boiling point by
the heating system to generate the solvent vapors. The resultant solvent
vapors act to displace the air within the degreaser which ensures that the
maximum amount of solvent will be available for cleaning. The upper level of
the solvent vapor is controlled by the cooling system which contains condenser
coils located part of the way up the sidewalls of the degreaser. The
condenser coils are designed to remove enough heat from the solvent vapor
layer so that condensation of solvent onto the cooling coils minimizes the
diffusional loss of solvent vapors away from the degreaser. Thus, a heat
balance is maintained within the vapor degreaser which simultaneously allows
large quantities of solvent vapors to be generated as well as contained.
This balance enables parts to be effectively cleaned and the solvent continuously
distilled.
There are two basic types of vapor degreasers: open top vapor degreasers
and conveyorized degreasers. Open top vapor degreasers are batch operated.
Parts to be cleaned are generally racked together in a vapor-permeable basket
which is then introduced through the top of the unit into the vapor zone
where condensation can then take place. In addition to condensing coils,
most open top vapor degreasers are also equipped with a water jacket which
provides additional cooling to prevent hot solvent vapors from convecting up
the degreaser sidewalls and out the top of the degreaser.
The principles by which a conveyorized degreaser operates are identical
to those of an open top vapor degreaser, with the exception that conveyorized
units use an automated conveyor system. Parts are continuously or multiply
loaded and then conducted through the degreaser via the conveyor system.
2-5
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In contrast to open top units, conveyorized degreasers almost always
contain the solvent and solvent vapors in an enclosed or hooded tank to
control solvent losses due to diffusion and convective air motion around
the degreaser. Due to the inherently greater load processing capability
of conveyorized degreasers relative to similarly sized open top units,
they are most commonly found in plants with a large quantity of parts to
be cleaned.
It has been estimated that approximately 174,000 cold cleaners,
41,800 open top vapor degreasers, and 5,200 conveyorized degreasers using
either trichloroethylene, perchloroethylene, 1,1,1-trichloroethane,
methylene chloride, or trichlorotrifluoroethane were in operation in 1980.
2.2 SELECTION OF CLEANING METHODS
The industrial cleaning of metallic parts and products is an extremely
broad and inherently diversified field. This is due to the extensive
number of different manufacturing, maintenance, and repair operations that
necessitate the use of clean components and assemblies in virtually every
aspect of processing and production. In general, an extensive set of
independent variables and technical considerations must be evaluated prior
to the selection of any method to fulfill a given cleaning requirement.
Major factors which influence the selection of any cleaning method
include:
t Physical and chemical properties of the contaminant to be
removed,
• Physical and chemical properties of the substrate on which a
contaminant is deposited,
t The amount of contaminant to be removed,
• The degree of .cleaning efficiency required,
• The size, shape, and complexity of parts or object to be
cleaned,
• The volume or number of parts or objects to be cleaned per unit
of time, and
• The substrate preparation required.
2-6
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Additional parameters important in the selection of a cleaning
process include: factory floor space available, water availability,
wastewater treatment availability, regulatory requirements, ventilation
requirements, energy consumption, and waste disposal.
Careful consideration of the above criteria often will not uniquely
specify any one particular cleaning method, but usually indicates several
methods which must then undergo further evaluation based on additional
factors such as the cost, safety, and environmental impacts associated
with the use of each candidate method. The relative importance assigned
each of these criteria will vary among potential users with similar
cleaning requirements depending on their production schedules, location,
or previous experience with a candidate cleaning method. Even after such
a selective screening process has been completed, final bench scale
testing is required frequently to quantify the effectiveness of a candidate
method under simulated operating conditions.
The cleaning methods most often used by industry principally rely on
4
one or more of the following mechanisms to facilitate contaminant removal:
• Solvent Action — Removal of contaminants through the use of
various halogenated and nonhalogenated solvents.
• Detergent Action -- Displacement of contaminants through the use
of various surface active agents (surfactants). These compounds
exhibit a greater chemical attraction to the substrate than for
the contaminants adhering to the substrate. This difference in
affinities preferentially removes the contaminant through
displacement by the surfactant.
• Chemical Reaction -- Use of various chemical compounds to react
with contaminants in such a way as to form soluble inert reaction
products which are then removed from the substrate.
• Mechanical Action — Use of mechanical energy applied through
techniques such as brushing, spraying, abrasion, impaction, or
wiping to displace the contaminant from the substrate.
In order to consider the applicability of one of the preceding
cleaning mechanisms to a given cleaning requirement, it is important that
the type of contaminant to be removed be characterized accurately.
Commonly encountered industrial contaminants are classifiable into six
principal types: '
2-7
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• Pigmented Drawing Compounds -- These materials commonly are used
in press and punch working procedures. They normally consist of
oil-based compounds to which a pigment such as lime, talc, chalk,
sulfur, lithipone, or graphite is added to help overcome the
frictional resistance of the machining operation, and to increase
the formability of a material. Pigmented drawing compounds
generally are used in press fabrication of parts with complex
shapes.
• Unpigmented Drawing Compounds -- These materials usually are
formulated with mineral oils and greases, vegetable or animal
oils, and/or fats. These compounds are used in the press forming
of simple to moderately complex shaped parts.
• Polishing and Buffing Compounds -- The materials are composed of
varying combinations of greases, metallic soaps, abrasives, and
waxes. These compounds may also contain very fine metal
particles following a polishing or buffing operation.
• Cutting and Grinding Fluids -- These compounds consist of a
variety of plain and sulfurized mineral and fatty oils,
chlorinated mineral oils, soaps, salts, and saturated fatty
alcohols.
• Oxidation and Scale -- These materials consist of combinations of
rust, heavy metal salts, and assorted metallic oxides. Unlike
the preceding compounds, these substances are corrosion products
rather than additives used to increase the formability of the
material.
• Miscellaneous Surface Contaminants -- This class of contaminants
includes a broad range of commonly encountered industrial soils
such as metal chips, carbon deposits, fluxes, quenching oils, and
various salt deposits.
Halogenated solvents are used to remove greases and oils such as the
unpigmented drawing compounds. They are somewhat limited in effectiveness
in the removal of pigmented drawing compounds, polishing and buffing
compounds, or cutting and grinding compounds. Solvent degreasing with
spraying or ultrasonic agitation can remove these contaminants when the
media carrying the abrasives are solvent soluble. When the media are
water soluble or soluble in alkaline solutions, aqueous cleaning can be
effective. Pigmented drawing compounds, polishing and buffing compounds,
and cutting and grinding fluids are more difficult to remove from a
2-8
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metallic substrate due to their chemical inertness and strong adhesive
characteristics. Buffing compounds can be extremely difficult to remove
when they are "heat set" by the frictional heat generated by abrasion.
Substitutes to degreasing processes using halogenated solvents fall
under four broad categories: aqueous cleaning, emulsion cleaning, nonchemical
cleaning, and cleaning with other organic solvents. It is these four
methods which are analyzed for potential technical and economic
substitutability.
2.3 TECHNICAL ANALYSIS OF SUBSTITUTES
This section analyzes the technical feasiblity of substituting each
of the preceding alternative cleaning methods for degreasing with halo-
genated solvents. The section outlines how each substitute process
functions and analyzes whether each of the substitutes identified is a
complete or partial substitute in various applications, the adequacy of
each substitute's performance, the quality of the end product, availability
of equipment, materials, and technical skills required to utilize each
substitute, and the time required to implement the substitution.
2.3.1 Aqueous Cleaning
2.3.1.1 Process Description
Aqueous cleaning describes a wide range of water-based cleaning
methods used to remove contaminants from assorted materials. Simple hot
water, in combination with mechanical, electrical, or ultrasonic energy,
is considered to have adequate cleaning properties in many applications.
This effectiveness primarily derives from temperature-induced viscosity
changes in contaminants such as greases and oils, which along with subse-
quent agitation helps to remove a portion of the soil. This cleaning
action is usually supplemented with chemical agents which act to displace
soils rather than dissolving them in an organic solvent.
Aqueous cleaning techniques may be divided into five categories:
• Immersion or Soak Cleaning -- Work is placed into the cleaning
solution, allowed to soak, removed, rinsed, and then dried.
Removal of soils is dependent on surfactant action and heat.
2-9
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t Spray Cleaning -- This method adds mechanical energy from a
pressurized spray to improve cleaning efficiency. This technique
is often adapted for use with a conveyorized load handling system,
allowing large volumes of work to be processed.
• Ultrasonic Cleaning -- This process uses high frequency sound to
induce a rapid formation and collapse of gas bubbles (cavitation)
in the cleaning solution. The violent collapse of the bubbles
produces a strong cleaning action which supplements the cleaning
effectiveness of the solution.
t Electrocleaning — Metal parts to be cleaned are immersed in a
cleaning solution through which an electric current is conducted.
The parts act as the anode or cathode of the circuit. The water
in the cleaning solution is electrolytically decomposed on the
work, releasing large volumes of tiny hydrogen and oxygen
bubbles. The evolved bubbles impart a powerful agitation aiding
in lifting and removing contaminants.
• Steam Cleaning -- A pressurized steam spray is mixed with small
amounts of alkaline cleaning solution to remove contaminants.
The high pressure and temperature of the mixture reduces the
viscosity of the contaminants and displaces them through the
impingement of the spray.
Aqueous cleaning systems are classified into two general types based
on the pH of the cleaning solution employed: alkaline cleaners and acid
cleaners. Alkaline cleaning compounds consist of various combinations of
builders (alkaline salts) and surfactants. Alkaline cleaning compounds
remove contaminants through one or more of the following process:
g
emulsification, dispersion, wetting action, aggregation, and saponification.
Builders form the largest percentage ingredient of an alkaline cleaner.
Frequently used builders are derived from the sodium salts of the carbonates,
q
phosphates, silicates, and hydroxides. Detergents and soaps are the two
types of surfactants used in alkaline cleaning compounds. Surfactants
belonging to the detergent class are the most widely used due to their
superior ability to soften water, disperse soil, and rinse freely away from
the substrate being cleaned. Commonly used surfactants include anionic,
onic, nonionic, and amphoteric detergents.
Acid cleaners are aqueous solutions consisting of acids or acid salts,
ting agents or detergents, and occasionally organic solvents which are
used to remove oil, dirt, or oxides from metal surfaces. Acid cleaning
compounds may be based on organic acids such as acetic, oxalic, or cresylic
acid, or inorganic acids such as sulfuric, nitric, or hydrochloric acid.
2-10
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Cleaning techniques used with acid cleaners include wiping, spraying,
immersion, and electrolytic and ultrasonic cleaning. Agitation of some type
is normally used in immersion applications, with spraying and ultrasonics
techniques used for parts or objects with complex shapes.
2.3.1.2 Method of Substitution
The design and operating principles of vapor degreasing and aqueous
cleaning equipment are too divergent to permit any large scale engineering
effort to modify vapor degreasers into aqueous cleaning machinery.
Solvent cleaning processes concentrate soil and contaminants for appropriate
disposal, while aqueous processes disperse contaminants. Therefore, the
substitution of aqueous cleaners (alkaline or acid) requires that new
cleaning systems be procured and installed to replace existing vapor
degreasers. Furthermore, any ancillary equipment associated with the use
of a vapor degreasing system, such as solvent recovery stills, carbon
adsorption columns, or solvent storage tanks, would also be of no
practical use in an aqueous cleaning system. Since the majority of vapor
degreasers have been integrated into manufacturing, maintenance, or repair
operations, substitution of an aqueous cleaning unit could also necessitate
the reevaluation of any existing load handling system's ability to deliver
parts for processing to the replacement unit. Depending on plant
processing operations, modifications in hoists, conveyorized load handling
systems, or equipment relocations could be required. Cleaning operations
substituting an aqueous system for a vapor degreaser may also require
changes in utilities services such as the need for additional wiring or
plumbing alterations to accommodate the substitute system. Since energy
requirements are greater than that required for solvent cleaning systems,
additional steam generating capacity may be needed if not available already.
In addition, space requirements for alkaline cleaning systems may be
greater.
The amount of time required to implement the substitution of an
aqueous cleaning system for a vapor degresser will vary depending on
whether the aqueous cleaning equipment is in stock or whether custom
engineering of a replacement system is required. The normal period of
time between ordering and receipt of a stock aqueous cleaning system is 4
to 6 weeks. During times of peak ordering or exceptionally heavy demand,
2-11
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delivery times for stock cleaning systems can be extended to 12 weeks.
Should the particular cleaning requirement necessitate the development of
a custom engineered cleaning system of nominal complexity, the time
needed for design work and manufacturing averages approximately 8 weeks
prior to shipment. Cleaning systems of intermediate complexity on average
take 16 weeks to develop while systems requiring extreme complexity and
parts handling sophistication normally take about 16 to 20 weeks to
custom design and produce. Manufacturers of aqueous cleaning equipment
also generally assist in the installation of their cleaning equipment by
providing on-site advice on system placement, utilities connections, and
ways in which the system can best be integrated into existing manufacturing,
maintenance, or repair operations within the plant.
Substitution of aqueous cleaners for cold halogenated solvent cleaning
will not, in all cases, necessitate the total replacement of all solvent
cleaning equipment. This is because some manufacturers design the ability
to use a variety of different cleaning agents into their equipment in order
11 12
to increase its versatility. ' In such a case, substitution would only
require a change of cleaning medium as opposed to any extensive modification
of plant equipment or processes. For plants using cold cleaning systems
that are not adaptable to the use of aqueous cleaning agents, replacement
of existing equipment would be required along with the possibility of some
type of plant modifications such as equipment relocation or changes in the
manufacturing sequence may be needed to accomnodate the substitute system.
The degree of such modifications, however, is not likely to exceed that
involved in substitution away from a vapor degreasing system, and in most
cases will be less since many cold solvent cleaning operations are generally
simpler in design due to intermittent cleaning demands, lower work volumes,
or the need to satisfy less stringent cleaning requirements.
Based on contact with a manufacturer of aqueous cleaning equipment, the
time required for a user of a cold cleaning system using halogenated
solvents to retrofit with an aqueous cleaning system will probably not
exceed 12 weeks. Most users of cold cleaning equipment would experience
a substantially shorter transition time since the majority of industrial
2-12
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cold cleaning operations are manually batch-loaded; therefore, no capital
expenditures or additional downtime would be incurred to modify or replace
existing load handling equipment.
2.3.1.3 Degree of Substitution
Historically, the use of aqueous cleaning by industry has been
commonplace. The general availability of water, its low cost, and familiarity
combine to make it a widely used cleaning medium. Table 2-3 shows the
relative extent to which alkaline washing systems and solvent-based systems
were used by nine two-digit SICs in 1976. These industries comprise the
majority of industries engaged in metal cleaning operations. When the
percent of plants using alkaline washing exclusively are taken together
with those that use both alkaline and solvent systems jointly, it is apparent
that alkaline washing systems are one of the most popular methods chosen
for metal cleaning.
Cleaning systems have been designed for use with alkaline and acidic
compounds that produce cleaning results comparable or superior to those
systems which use halogenated solvents. ' ' One study designed to
evaluate the comparative effectiveness of aqueous and solvent methods for
cleaning various metals was conducted by Rockwell International at the
Federal government's Rocky Flats nuclear weapons facility in Golden,
Colorado. During the study, metals coated with common industrial soils
were cleaned by ultrasonic vapor degreasing in trichloroethylene and
1,1,1-trichloroethane as well as being cleaned ultrasonically in an
alkaline detergent solution. Ultrasonic vapor degreasing had been
extensively used at Rocky Flats prior to initiation of the study. The
metals investigated included stainless steel, beryllium, uranium-niobium
alloy, and unalloyed uranium. Following cleaning in each medium, samples
from that run were analyzed for the types and amounts of various residues
left on the surface of each metal. Methods used in the residue analysis
included scanning electron microscopy, nondispersive x-ray and x-ray
diffraction techniques, infrared emission spectroscopy, and mass spectroscopy.
Numerous runs were conducted with each metal and cleaning medium so that
•2-13
-------
TABLE 2-3. USE OF SOLVENT AND ALKALINE CLEANING SYSTEMS BY SIC CODE, 1976
13
ro
i
23
33
34
35
36
37
38
39
Standard
industrial
classification
Metal Furniture
Primary Metals
Fabricated Products
Nonelectrical Machinery
Electric Equipment
Transportation Equipment
Instruments & Clocks
Miscellaneous Industry
Percentage
of plants
using solvent
systems9
29
21
23
33
34
22
42
31
Percentage
of plants
using alkal ine
systems
25
18
21
14
14
20
6
22
Percentage
of plants
using solvent
and alkaline
systems
17
19
19
19
21
28
23
8
Percentage
of plants
using no
metal cleaning
system
29
42
37
34
31
30
29
39
'Halogenated and nonhalogenated solvents are included in this classification.
-------
the respective findings could be compared between separate metals and
cleaning techniques as well as to a set of uncleaned controls. Significant
results of the study include:
• The aqueous cleaning method cleaned all four sample metals as
well as or better than ultrasonic vapor degreasing with
trichloroethylene or 1,1,1-trichloroethane.
• No evidence of any significant amount of adsorbed residual water
could be detected for any of the metals exposed to the aqueous
cleaning environment.
• Corrosion tests showed the use of an alkaline cleaning agent to
be chemically compatible with both the ferrous and nonferrous
metals tested.
• Aqueous cleaning can remove potentially damaging chloride
residues in industrial soils that cannot be removed by ultrasonic
vapor degreasing methods.
In addition to the preceding results, the stainless steel parts were
welded and brazed by various processes to determine the effect of each
cleaning method on weld integrity. Subsequent analyses by ultrasonic and
radiographic techniques for porosity, microcracks, and inclusions showed a
slightly lower rejection rate for the preweld aqueous cleaned joints than
for the preweld solvent cleaned joints. Based on study findings, the use
of ultrasonic vapor degreasing at the Rocky Flats facility was replaced
with an ultrasonic aqueous cleaning system.
A similar study undertaken by General Electric Company in Waynesboro,
Virginia has also shown that aqueous systems are capable of achieving
extremely exacting levels of cleanliness. Results of the study have
shown that under identical operating conditions and workloads, aqueous
cleaning of printed circuit boards can be done up to six times more
18
effectively than similar solvent-based systems. However, it should be
noted that the case of G.E., Waynesboro is an individual situation, and
19
should not be considered general practice.
An example where aqueous cleaning could not be used as a substitute
is at the Boeing Military Airplane Company in Wichita, Kansas. Boeing
produces printed wiring assemblies associated with a major avionics system
contract. In the summer of 1980, humidity testing showed the assemblies
2-15
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to be defective, and the aqueous/solvent cleaning system was replaced with
an aqueous system. Further testing showed these assemblies were also
defective. Initial research showed that contaminants were found to be
present after either cleaning process. The contaminants were of two
forms, trace amounts of ionic metals (Sn and Pb), and a thin organic
overcoat. Further research by Boeing, with assistance from DuPont, found
®
the only way to remove the contaminants was to use Freon TMC (50 percent
(R)
trichlorotrifluoroethane and 50 percent methylene chloride) and Freon IMS
(trichlorotrifluoroethane in a constant boiling blend with 5.7 percent
methanol), followed by an isopropanol spray rinse. Aqueous cleaning alone
20
was inadequate in cleaning printed wiring assemblies.
Although the use of water-based cleaning systems is widespread
throughout industry, the use of halogenated solvents has continued for
several reasons. The traditionally low cost of halogenated solvents due
to comparatively inexpensive petroleum feedstocks and energy resources
during the last several decades made the large scale use of these solvents
widely affordable. The development of self-contained equipment specifically
designed to clean sizable volumes of work with solvents also assisted in
their growth and application. The development of chemical stabilizer
systems that could be added to a solvent to prevent hydrolysis and inhibit
the formation of oxidation products enabled halogenated solvents to be
used much more effectively in the vapor degreasing process. The high
degree of chemical compatibility of most halogenated solvents with a wide
range of common engineering metals, plastics, glasses, and elastomers
allowed for the cleaning of workloads consisting of mixed material composition
which helped to eliminate the need to segregate parts based on susceptibility
to chemical attack. Finally, the historical absence of any significant
Federal, State, and local regulatory pressures with respect to workplace
exposure or the environmental impacts of solvent usage also enabled the
use of solvents in metal cleaning to expand and diversify. Solvent
cleaning, aqueous cleaning, and other cleaning processes were chosen
solely on their engineering merit.
Changes in the preceding factors, however, are forcing industry to
reevaluate its use of solvent-based cleaning in favor of the increasing
15 21
usage of nonsolvent-based cleaning methods. ' Escalating prices for
2-16
-------
solvents and energy along with the development of listings, regulations
and guidelines which have been proposed or adopted in many cases concerning
the use and disposal of solvents, have served to increase the use of
alkaline washing systems relative to that of solvents. In addition,
continuing research and development on the part of aqueous cleaning
equipment manufacturers has advanced the state of the art of aqueous
cleaning to the point of close technical and economic parity with solvent
1621
systems in most applications. ' The essentially equivalent ability of
aqueous and solvent-based systems to service a diverse range of industrial
cleaning requirements is also apparent in that the manufacturers of
either type of system view the market for their equipment as being identical,
i e both sectors regard themselves and their products as being mutually
„... 14,15,21,22,23
competitive.
One industry known to be phasing out solvent metal cleaning in favor
of aqueous cleaning is the automotive manufacturing industry. Concern
over worker exposure to potentially hazardous solvents along with the
desire to minimize spent solvent disposal costs have caused major automotive
manufacturers, such as General Motors to become large scale users of
aqueous cleaning processes. ' This phase out of solvent metal cleaning
has affected both cold cleaning and vapor degreasing operations. Aqueous
cleaning systems are currently used by the automotive industry for virtually
all manufacturing operations involving the processing of parts ranging
from engine components to automobile bodies.
While the extent to which aqueous systems can be regarded as a
realistic alternative to solvent systems appears to be significant for
many degreasing tasks, there are areas where complete substitution may be
infeasible and halogenated solvents must be used. All such restrictions
on the use of aqueous systems cannot be specified due to the case specific
requirements of each individual manufacturing and degreasing operation.
Aqueous systems are likely to leave residual water of parts cleaned,
particularly in recesses. The retained moisture can induce corrosion.
When aqueous cleaning solutions must have strong alkalinity (pH >10) to
achieve effective cleaning, chemical attack on aluminum and other reactive
2-17
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metals can be expected. Specific areas not suitable to aqueous cleaning
are known to include the maintenance cleaning of complex electromechanical
devices such as generators or motors. Use of aqueous cleaning is limited
in these cases since electrically conductive residues left on or inside
such equipment may adversely affect its performance. Another area with
poor substitution potential is the cleaning of parts that require a low
26
moisture content such as refrigeration equipment. In some instances,
the construction and geometry of parts can prohibit the use of aqueous
cleaning techniques. Small, delicate parts may not be cleaned adequately
if they possess intricate shapes, since the spray, flushing, or agitation
affects of aqueous washing equipment may not reach portions of the part's
surfaces that are recessed or otherwise protected from cleaning. Use of
aqueous cleaning systems also may be limited, in those areas of the
country where water is not available on a consistent basis.
2.3.1.4 Resource Availability
Major manufacturers of aqueous cleaning equipment and cleaning
compounds were contacted to determine the ability of each sector to meet
current and future demand for its products. In all cases, both sectors
viewed their respective markets as steadily expanding due to a combination
of factors precipitating a decrease in the use of solvents for metal
cleaning. ' ' Estimates place the growth of the market for aqueous
cleaning systems at approximately 10 percent annually. According to
leading manufacturers, sufficient production capacity exists within the
industry to service at least a doubling of demand without the need to
28 29 30
invest in additional capital equipment, plant space, or personnel. 0»">JU
2.3.2 Emulsion Cleaning
2.3.2.1 Process Description
Emulsion cleaning is a synthesis of organic solvent cleaning and
aqueous cleaning. Emulsion cleaners remove contaminants through the
action of an organic solvent which has been dispersed or suspended as
fine droplets in an aqueous medium with the aid of emulsifying and coupling
agents. The emulsifying agent disperses the solvent into the water while
2-18
-------
the coupling agent provides a mechanism for controlling the size of the
31
solvent droplet. The emulsifying and coupling agents enable large
amounts of solvent surface area to be created in an emulsion cleaner due
to the extremely small droplet size. The availability of large amounts
of solvent surface area in an emulsion cleaner allow cleaning results to
be attained that are comparable to straight solvent cleaning while using
32
less solvent. The organic solvent component of an emulsion cleaner
generally consists of mineral spirits or similar petroleum fractions,
sometimes blended with chlorinated aromatic or naphthenic solvents to
improve the overall solvency of the formulation.
The most common application methods used with emulsion cleaners are
immersion and spray cleaning. In the first method, parts are allowed to
soak in a tank containing a ratio of one part emulsion concentrate to
20 parts water. Temperatures used in this type of immersion cleaning
range from ambient up to about 10°C below the flash point of the solvent
32
used in the emulsion cleaner. In the second method, cleaning is enhanced
by the mechanical energy of the spray. Because the energy of an impinging
solvent droplet is directly proportional to its mass, coarser solvent
emulsions tend to increase the effectiveness of spray techniques. Typical
solvent concentrations used in emulsion washing equipment vary from two
to five percent by volume. Depending on the specific formulation of the
emulsion cleaner and the concentration at which it is prepared, the
solvent may serve only to reduce the viscosity of the contaminants to
make them more readily dispersable by detergents that may be compounded
into the product as part of the emulsifying system. The size and
geometry of the part and the nature of the contaminant are the main
criteria for selecting between the use of immersion or spray cleaning
techniques.
2.3.2.2 Method of Substitution
As in the case of aqueous cleaning equipment, use of emulsion cleaners
as a substitute system for a vapor degreaser would necessitate the replacement
of the degreaser and any associated support equipment. Substitution of
2-19
-------
emulsion cleaners for halogenated solvents would not require the replacement
of most cold cleaning equipment because most manufacturers of cold cleaning
machinery have designed the ability to use emulsion cleaners into their
13 14 34
equipment to increase its versatility. ' '
The use of emulsion cleaners requires no special technical skills
beyond those required for straight solvent cleaning operations. The
ability of most cold cleaning machines to use emulsion cleaners inter-
changably with solvents would not necessitate any gross changes in a
metal cleaning operation such that a greater degree of expertise would be
required of the user to effectively employ the emulsion cleaner. Additionally,
substitution would involve only the changing of cleaning medium within a
system. The time required for conversion to this substitute would be
minimal, and it is not anticipated to interfere to any significant degree
in its implementation.
2.3.2.3 Degree of Substitution
Emulsion cleaners were developed to fill the gap between solvent
vapor degreasing and alkaline cleaning. Subsequent research and development
has produced water-based cleaners that have been designed to replace
products such as petroleum solvents and halogenated solvents. As a
result, many emulsion cleaners can be used to remove the same types of
35
contaminants that are removable by the solvents they replace. Emulsion
cleaners are suitable for use on most metals because of their neutral to
slightly alkaline pH. The most widespread use of emulsion cleaners is
for the in-process cleaning of metal parts to remove contaminants such as
pigmented and unpigmented drawing compounds, lubricants, cutting fluids,
and metal chips that may be acquired in a variety of machine-based production
systems. In these applications, emulsion cleaners act as a partial
substitute because they offer a means of achieving rapid superficial
cleaning of parts throughout manufacture and assembly. According to
comments received by DuPont (Appendix A), emulsion cleaning is not an
alternative to CFC-113. Water, unless doped wth surfactants, has a high
surface tension (72 dynes/cm vs. 17.3 dynes/cm for CFC-113 at 25°C)
and thus does not wet surfaces or penetrate interstices as well.
2-20
-------
The most important characteristic of all emulsion cleaners is that
they deposit a light film of residual oil onto metal parts as they emerge
from the cleaning process. Depending on the application involved, this
oil film can be extremely valuable in that it provides a significant
degree of rust protection for metal parts during their fabrication and
assembly. It also helps ensure the corrosion resistance of parts that
undergo several weeks of storage before being assembled or shipped.
However, for manufacturing, maintenance, or repair operations that require
processed parts to be free of any oil residue, emulsion cleaners should
not be substituted. Subsequent cleaning by another method such as alkaline
washing would be necessary to achieve a totally clean part. Depending on
the particular cleaning requirement, the use of emulsion cleaners would
only be effective as a precleaning agent prior to final processing by
another cleaning system.
In 1976, approximately 15 percent by volume of all metal cleaning
compounds used domestically were emulsion cleaners. Most manufacturing
or maintenance operations in which metal parts undergo sequential machining
followed by cold cleaning with halogenated solvents prior to final assembly,
storage, or shipment, can be considered as candidates for substitution
with an emulsion cleaner. For the purposes of this study, contact was
made with a manufacturer of cold cleaning machinery and emulsion cleaning
compounds to assist in the identification of emulsion cleaner users so
that a profile of current applications using emulsion cleaners could be
developed. Based on the response received the large degree of interchangeability
of emulsion and solvent-based cleaning media prevented identification of
23
companies using emulsion cleaners in manufacturing and maintenance operations.
However, literature review indicated the following examples in which
emulsion cleaning has been employed in applications that traditionally
have employed solvents:
• Cleaning and coating of welded auto wheels prior to shipment,
t Cleaning and protection of engine blocks prior to assembly,
• Steel sheet metal cleaning and coating for rust protection,
2-21
-------
t Cleaning and rust protection of bearings in process and before
final assembly, and
• Cleaning of aluminum reflectors.
Emulsion cleaners have been chosen for these and similar tasks because
they are usually less expensive to use, less toxic, easier to treat and
dispose of, and offer a longer working life than the solvents they replace.
As mentioned above, emulsion cleaners generally are not well suited to
providing "chemically" clean surfaces due to their tendency to deposit a
thin oil film on parts emerging from the cleaning process. Hence, emulsion
cleaners do not represent a technically viable substitute for vapor
degreasing operation because vapor degreasing is usually chosen for its
ability to produce a part with surfaces devoid of any significant amount of
grease or oil. Thus, for any application in which the absence of any
chemical residue is critical, emulsion cleaning could not be considered a
technically feasible substitute for halogenated solvents since any emulsion
cleaner chosen would not produce a product of acceptable quality. Many
manufacturing processes in the microelectronics industry for example cannot
tolerate the light oil film that is characteristic of emulsion cleaners and
so use solvent and/or aqueous cleaning systems. Parts destined for later
finishing, such as in electroplating, may require a secondary solvent or
aqueous cleaning following an initial emulsion cleaning to remove unwanted
surface oils. Analogous cleaning situations exist in the manufacture of
many sophisticated electromechanical devices such as medical machinery,
missle propulsion systems, and photographical equipment. The cleaning
requirements of these devices are similar in that halogenated solvents
frequently possess the most complete and compatible set of properties
necessary to ensure reliable product performance.
As with an aqueous system, emulsion cleaning generally requires
more space and energy than vapor degreasing systems. Although emulsion
cleaning does provide some ability to solubilize solvent soluble soils
compared with an aqueous system, the solvent portion of the emulsion is a
relatively small percentage, and the ability to dissolve solvent soluble
soils before saturating the emulsion cleaner is limited.
2-22
-------
2.3.2.4 Resource Availability
Major manufacturers of both solvent and aqueous cleaning equipment
are also the principal suppliers of emulsion cleaners. As in the case of
aqueous cleaning systems, growth in the market for emulsion cleaners is
about 10 percent annually with adequate production capacity in reserve to
23 28 29 30
handle a two to three fold increase in demand. ' ' '
2.3.3 Nonchemical Cleaning
2.3.3.1 Process Description
The principal nonchemical substitute for solvents used in metal
cleaning operations is abrasive blasting. Abrasive blasting relies on
the mechanical energy of impacting particles to remove contaminants from
a variety of parts and materials. Particles are entrained in a moving
carrier medium such as air or water, and then directed against the surface
of the work being processed. The cleaning effectiveness is a function of
the particle's abrasive properties, hardness, size, and energy of impact.
Materials commonly used as abrasives include silica sand, steel
grit, aluminum oxide, nut shells, and glass beads. Selection of a suitable
abrasive for a specific application is influenced by the type of surface
contamination to be removed, the size and shape of the work piece, the
38
finish desired, and the rate of production required. Cleaning done by
abrasive blasting materials is nonselective with respect to the type of
surface being cleaned since no chemical mechanism for contaminant removal
39
is involved in the process.
Abrasive blast cleaning may be done by portable equipment which can
be moved from job to job, or done in specially designed, sealed compartments
Portable blasting equipment is used for the cleaning of large objects
such as storage tanks, bridge superstructures, and construction equipment.
Blasting systems which use enclosed compartments are designed to clean
medium to small size work pieces which can be transported to the blasting
system for processing. Self-contained blasting systems can be used to
clean such objects as engine heads, water meters, and die castings.
2-23
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2.3.3.2 Method of Substitution
Use of abrasive blasting equipment, whether portable or self-contained,
as a substitute method for cleaning with halogenated solvents, would
necessitate the replacement of the solvent-based cleaning equipment.
However, as the subsequent section illustrates, no significant degree of
technical interchangability exists between vapor degreasing and abrasive
blast cleaning processes. Consequently, only those cold cleaning operations
using halogenated solvents would be possible candidates for substitution
to the use of a blast cleaning system. The greatest potential for substitution
would be through the use of self-contained, compartmentalized blasting
systems capable of cleaning small to medium size workloads of simple
geometry.
Contact with a leading manufacturer of abrasive cleaning systems
indicated that the time required to deliver a complete blasting system
was approximately 8 to 12 weeks depending on seasonal demand and backorder
status.40 Installation of the equipment is straightforward and requires
only a 115 to 230 volt service connection depending on the size of equipment
chosen. The degree of technical skill required to operate the substitute
system is minimal and consists mainly of selecting the correct air pressure
used to propel the abrasive media such that the impacting particles do
not possess kinetic energies in excess of those required for the specific
cleaning application.
2.3.3.3 Degree of Substitution
Abrasive blasting systems require a high level of manual operation
in order to clean parts adequately. Portable blasting systems must be
transported to the site where cleaning is to occur while stationary
systems must be handloaded with separate parts, each needing individualized
cleaning to assure an effective result. Additionally, abrasive blasting
systems are used to remove contaminants other than oils and greases such
as corrosion products, heat scale, and carbon deposits, which due to
their respective chemical structures are not attacked readily by solvents.
In consideration of these and other constraining factors, portable and
stationary abrasive blasting systems offer no significant degree of
technical substitutability for the vapor degreasing cleaning process.
2-24
-------
Stationary abrasive blasting systems do possess a sufficient degree
of cleaning utility to be considered a limited substitute for some cold
cleaning applications using halogenated solvents. The greatest degree of
overlap between cold solvent cleaning and abrasive blasting occurs in the
cleaning of internal combustion engine parts and related components prior
to maintenance, rebuilding, and repair operations. Parts such as piston
rods, pumps, connecting rods, and valves may be blasted clean under
suitably controlled conditions of particle size, hardness, and impact
velocity without alteration of critical tolerances. Critical cleaning of
electronic, medical, and other equipment containing small interstices and
close-packed electronic assemblies cannot be cleaned by blast cleaning.
The key to the successful use of blast cleaning in these applications
is the selection of an appropriate cleaning medium. Glass beads generally
are chosen for the cleaning of precision parts. When used properly,
abrasion of surface metal is negligible. The beads resist becoming
imbedded in the surface being cleaned due to their sphericity. However,
because blast cleaning is unable remove contaminants from metal parts
containing complex internal passages, such as the gasoline passages in a
carburetor, the extent to which blasting can be considered a technically
viable substitute for cold cleaning with halogenated solvents is restricted
41
to a relatively small number of applications.
2.3.3.4 Resource Availability
Published information concerning the abrasive cleaning industry is
limited. Contact with a major manufacturer of both portable and stationary
blasting systems indicates that capacity and usage estimates for abrasive
blast cleaning machinery are not available. However, the same manufacturer's
product literature indicates that past and current abrasive blast cleaning
equipment customers are located in a variety of industries including
chemicals, steel, and rubber. However, it appears unlikely that blast
cleaning is being used for most of the same applications as solvent
cleaning in these industries. Nevertheless, the demand from these user
industries for blast cleaning equipment, even if destined for other
cleaning applications not compatible with solvents, tends to indicate
that sufficient capacity exists to service the small increase in demand
2-25
-------
anticipated to result from any degree of substitution using these
nonchemical cleaning systems.
2.3.4 Cleaning with Other Organic Solvents
2.3.4.1 Process Description
Solvent metal cleaning uses organic solvents to remove a wide variety
of contaminants from the surfaces of parts being processed in manufacturing,
maintenance, and repair operations. Examples of typical contaminants
susceptible to solvent removal include most greases, oils, and waxes as
well as an assortment of resins and polymers. Solvents used for these
purposes may be grouped into four broad categories: aliphatic, aromatic,
oxygenated, and halogenated. The last category includes a large number of
brominated, fluorinated, and chlorinated hydrocarbons suitable in varying
degrees for use as metal cleaning solvents. Trichloroethylene, perchloro-
ethylene, 1,1,1-trichloroethane, methylene chloride, carbon tetrachloride,
and trichlorotrifluoroethane are all members of the halogenated solvent
category.
2.3.4.2 Method of Substitution
The use of substitute organic solvents in those cold cleaning
applications employing halogenated solvents will not, for most users,
entail any extensive modification of existing solvent cleaning equipment.
Substitution for the majority of users of cold cleaning processes would
involve only the changing of one solvent for another. Several factors
combine to promote a significant degree of solvent interchangability.
These factors include:
• The moderate to high solvency exhibited by most organic solvents
for commonly encountered industrial contaminants;
• The chemical compatibility of most organic solvents for almost
all ferrous and nonferrous metals;
e Insensitivity of most cold cleaning techniques such as hand-
wiping and immersion to the type of solvent used; and
• The ability of most cold cleaning equipment to operate effectively
and clean adequately with a variety of solvents typically used
in metal cleaning applications.
2-26
-------
While the above factors assure that in many applications one or more
substitute solvents may be able to perform adequately as a replacement
for a halogenated solvent in a specific cold cleaning operation, the
ability to use a substitute solvent is not universal for all types of
cold cleaning equipment. Conveyorized cold cleaning machines such as
those designed for use as in-line printed circuit board defluxers could
not convert to the use of a substitute organic solvent because their
enclosed design would tend to accumulate potentially explosive amounts of
solvent vapor. Additionally, the inability of many solvents to remove
the specialized solder fluxes used in the manufacture of printed circuit
boards (without imparting damage to the board substrate) minimizes the
potential for large scale use of substitute organic solvents in much of
the microelectronics industry. Substitution of aliphatic, aromatic, and
oxygenated solvents may not satisfy cleaning requirements in critical
cleaning applications.
The substitution of cold cleaning with other organic solvents for
vapor degreasing would necessitate the acquisition of new cleaning equipment
due to the distinct differences in the nature of the cleaning processes.
For cold cleaning equipment to approach vapor degreasing in cleaning
efficiency, large amounts of solvent agitation are necessary to make up
for the absence of the high heat input that underlies vapor degreasing's
cleaning effectiveness. Because many vapor degreasers do not contain any
solvent agitation mechanism, they could not be used as cold cleaning
machines. Owners of vapor degreasers would have to replace their existing
equipment with cold cleaning machinery of comparable production capability.
Due to the unique combination of physical and chemical properties
that a solvent must possess in order to function properly in the vapor
degreasing process, much less latitude exists for substituting other
organic solvents in vapor degreasing applications than for cold cleaning.
A partial list of those solvent characteristics of particular importance
to vapor degreasing include:
2-27
-------
• High vapor density relative to air,
• Chemically stable, nonflammable, and nonexplosive under operating
conditions,
• Low latent heat of vaporization and low specific heat so that a
maximum amount of solvent will condense on a given mass of
metal and keep heat input requirements to a minimum,
• Boiling point low enough to permit the solvent to be easily
separated from contaminants by simple distillation but high
enough to allow sufficient solvent vapor condensation on the
work to insure adequate cleaning, and
t Low toxicity.
Currently, there is only one other halogenated solvent capable of
meeting the above criteria: trichlorofluoromethane (CFC-11). Trichloro-
fluoromethane has solvent characteristics that closely approximate those
of trifluorotrichloroethane (CFC-113). This functional similarity has
enabled it to be used for some of the same critical cleaning applications
as CFC-113, such as in the cleaning of delicate electromechanical parts
and chemically sensitive plastics such as polycarbonates. However, the
relatively low boiling point of CFC-11 (24°C), and concern over its ozone
depletion potential historically has prevented any widespread vapor
degreasing applications. Nevertheless, experimental vapor degreasing
systems have been designed around CFC-ll's thermodynamic properties.
Results of prototype testing indicate that CFC-11 can be used successfully
to remove most common metal working contaminants with the exception of
42
high melting point waxes. Substitution of CFC-11 for other vapor
degreasing solvents would necessitate reducing the heat input into the
degreaser and supplying additional cooling capacity (to help prevent
excessive solvent losses from diffusion) through addition of a refrigerated
freeboard device.
Little or no increase in the degree of technical skill would be
required to operate a cold cleaning system using nonhalogenated solvents
as opposed to a similar system using halogenated solvents. In many
cases, the same equipment can be used for either type of solvent so that
no new skills need be acquired and no installation of new equipment will
2-28
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be necessary. The length of time required to make a substitution for
nonhalogenated for halogenated solvent would be minimal because no new
equipment would be acquired and the widespread availability of alternative
solvents would not create any significant downtime for most solvent
cleaning operations of this type. Substitution of a cold cleaning system
using alternative organic solvents for a vapor degreasing system would
vary widely with respect to the time needed to implement the substitution.
Process variables including production volume, load handling systems, and
workload geometry may necessitate some degree of custom engineering,
which could increase the time required to achieve the substitution.
However, based on contacts with manufacturers of cold cleaning equipment,
the time required to procure the substitute cleaning system would be the
same as that needed to substitute an equivalent aqueous-based cleaning
process. Even in the case where extensive custom engineering is indicated,
the time necessary to design, construct, deliver, and install the substitute
system is not expected to exceed 20 weeks.
2.3.4.3 Degree of Substitution
Industrial cold cleaning applications exhibit such a great amount of
diversity with respect to process variables such as the physical and
chemical properties of objects being cleaned, type of contaminant removed,
production volume, and cleaning equipment used, that no single solvent
can be adapted for all purposes. Many situations exist in the cold
cleaning of metal parts where replacement of a halogenated solvent with
another organic solvent is possible. Drawing compounds, cutting and
grinding fluids, some polishing and buffing compounds, and miscellaneous
contaminants, such as metal chips, dirt, and corrosion inhibitors, are
all amendable to cleaning processes using nonhalogenated solvents. Most
manufacturing operations requiring the removal of these common metal
working compounds and by-products prior to further processing or assembly
are candidates for cleaning with nonhalogenated solvents. Because the
majority of manufacturing operations using cold cleaning employ relatively
simple techniques such as immersion and manual scrubbing, there is ususally
sufficient latitude within the process to allow the use of several substitute
solvents on an equivalent basis. Opportunities for substitution also
2-29
-------
exist for many users of halogenated solvents located in the maintenance
and service sectors of the economy. Sectors such as engine repair,
office machinery, and machine tool rebuilding possess similar requirements
that are adequately fulfilled by cold cleaning with nonhalogenated solvents.
The high degree of solvency offered by substitute organic solvents
for commonly used metal forming and drawing compounds frequently offers a
user several candidate solvents from which to choose the most suitable to
the particular application. Other factors which influence the choice of
a substitute solvent include solvent cost, flash point, toxicity, flammability,
and evaporation rate. Different users will weigh each of the above
factors differently in accordance to their particular application or
experience. For example, one user may consider evaporation rate more
important than toxicity, while another user with a similar cleaning
requirement may consider solvent cost to be the most important criterion.
Examples of some metal cleaning solvents which find widespread applicability
in cold cleaning operations are listed in Table 2-4.
While the ability to substitute other organic solvents for halogenated
solvents exists for a number of manufacturing and maintenance operations,
some specialty applications requiring extremely low residue contents
following cleaning are not particularly well suited to solvent substitution.
Aerospace, nuclear, and other precision industries frequently demand
white-room techniques which necessitate ultra-pure cleaning requirements
not readily met by cleaning media other than halogenated solvents.
Examples of exacting applications not particularly suited to solvent
substitution include the maintenance of nuclear fuel handling equipment,
cleaning of hydraulic systems, and the cleaning of high-tolerance injection
molds.
Vapor degreasing is generally chosen over cold cleaning when it is
perceived that a fairly high degree of cleanliness is required and that
there exists a production volume of sufficient magnitude to justify the
larger capital expenditure for vapor degreasing machinery. Hence, for
cold cleaning with other organic solvents to be a viable substitute for
vapor degreasing, the choice of an appropriate cold cleaning system
capable of both a high level of cleanliness and of handling a large
2-30
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TABLE 2-4. COMMON METAL CLEANING SOLVENTS41'42
Solvent
class/solvent
Oxygenated Hydrocarbons
Me t ha no 1
Ethanol
Isopropanol
Acetone
Methyl Ethyl Ketone
Aliphatic Hydrocarbons
Petroleum solvents
Cyclohexane
Aromatic Hydrocarbons
Toluene
Xylene
Halogenated Hydrocarbons
Chlorobenzene
o-Dlchlorobenzene
Trichlorofluoromethane (CFC-11)
Threshold
limit
value
(ppm)
200
1,000
400
1,000
200
200-500
300
200
100
75
50
1,000
Flash
point
58
60
70
3
28
M05
10
40
81
80
165
none
Flammable limits,
% by volume in
air at 20°C
Lower
6.0
3.3
2.7
2.2
1.8
0.8
1.4
1.3
1.1
1.3
2.2
Upper
36.5
19.0
12.0
13.0
11.5
6.0
8.4
7.0
6.6
7.1
9.2
Relative
evaporation
rate (n-Butyl
acetate = 1)
3.5
1.9
1.7
7.7
4.6
0.2
1.5
0.75
1.07
0.15
nonflammable
Pounds
per
gallon
at 68°F
6.60
6.62
6.57
6.59
6.71
6.43
6.52
7.26
7.25
9.19
10.84
12.42
Price per
pound
(first
quarter 1981)
$0.82
0.28
0.29
0.29
0.35
0.25
0.30
0.21
0.21
0.36
0.50
0.47
-------
production volume is important. Several manufacturers of industrial cold
cleaning machinery have recognized these criteria and have engineered
cleaning systems capable of processing comparable workloads with a cleaning
effectiveness comparable to that of vapor degreasing. High flash point
cleaning media such as petroleum solvents are typically used in these
applications. Such equipment substitutes high levels of mechanical
agitation for hot solvent vapor in order to achieve a degree of cleaning
effectiveness comparable to vapor degreasing. Typical cold cleaning
systems of this type process large workloads (up to several thousand
pounds of parts per single workload) by pneumatically agitating them up
and down in the solvent at speeds in excess of 130 times per minute.
The induced motion of the solvent provides a higher level of cleaning
effectiveness relative to spray or flushing techniques common on smaller
manually operated cold cleaning machines.
These larger types of cold cleaning equipment have found wide scale
use in those industries which are also the principal users of vapor
degreasing processes such as the transportation, printing, reconditioning/rebuilding
and metal working industries. Particular fields of application in the
metal working industry include metal fabricating, machine shop operations,
screw machine parts manufacturing, and tool and die production. Several
of the manufacturers offer custom designs for specialized cleaning needs
and consider the market for the equipment they produce to be fundamentally
the same as that of the manufacturers of vapor degreasers. While
there would still exist vapor degreasing applications for which substitution
of cold cleaning with other organic solvents would not be technically
feasible (such as microelectronics), many current users of vapor degreasing
could regard this type of cold cleaning machinery as a substitute capable
of high cleaning efficiencies for large production cleaning requirements.
The use of azeotropic mixtures of halogenated and nonhalogenated
solvents offer a degree of partial substitutability to the use of pure
halogenated solvents as vapor degreasing agents. An azeotropic solvent
mixture is a combination of several component solvents which boil at a
constant temperature such that the resulting vapor is of the same chemical
composition as the original liquid. An azeotropic solvent mixture can be
2-32
-------
used in a vapor degreaser without fear that the relative percentage of
each component in the mixture will be altered during the cleaning process.
The use of azeotropic solvent mixtures in vapor degreasing is fairly
common. Azeotropic solvent mixtures generally possess synergistically
enhanced cleaning characteristics that may be more effective than those
of a pure solvent for removing a particular contaminant. Examples of
azeotropic solvent mixtures used in vapor degreasing include a 70 percent/30 percent
blend of trichloroethylene with isopropanol or a 96 percent/4 percent
46
blend of trichlorotrifluoroethane with denatured ethanol. For the
majority of vapor degreasers, use of a solvent azeotrope will not entail
the retrofitting of any new solvent control or recovery equipment.
Additionally, little if any modifications in cooling capacity would be
required. Thus, azeotropic solvent mixtures, while not completely replacing
one of the five standard vapor degreasing solvents, can reduce the amount
used in vapor degreasing and thereby offer a partial substitute to the
use of the pure compounds.
The use of the halogenated solvent trichlorofluoromethane (CFC-11)
as a vapor degreasing agent offers the potential of being a complete
substitute cleaning compound for many degreasers using trichloroethylene,
1,1 ,1-trichloroethane, methylene chloride, and trichlorotrifluoroethane
(CFC-113). CFC-11 will not, in most cases, be a viable substitue for
vapor degreasers using perchloroethylene because its substantially lower
boiling point (24°C compared to 121°C for perc) would not adequately
remove high melting point waxes which usually require processing with
perchloroethylene. However, it is estimated that only about ten percent
of all open top vapor degreasers and conveyorized degreasers currently
47
use perchloroethylene.
CFC-11 has not been widely used as a vapor degreasing solvent because
of its high volatility and ozone depletion potential. However, one major
producer of both CFC-113 and CFC-11 has conducted prototype testing with
modified vapor degreasers for use with CFC-11 to evaluate its potential
42
as a metal cleaning solvent. Results of that study indicated that
CFC-11 can be used effectively as a vapor degreasing solvent to remove
the same types of industrial contaminants as the other degreasing solvents
2-33
-------
(except as previously noted). Follow-up contacts with the producer were
initiated to determine the feasibility of retrofitting existing vapor
48
degreasers to enable them to use CFC-11. According to the producer,
most existing vapor degreasers could be adapted for use with CFC-11
through the adjustment of the heat balance needed to maintain the boiling
solvent and the addition of a refrigerated freeboard device. Due to
differences in the physical properties of each solvent, the extent of the
modifications necessary to enable a vapor degreaser to use CFC-11 will
vary depending on the solvent the degreaser was using prior to substitution.
2.3.4.4 Resource Availability
Based on contacts with major producers of both halogenated and
nonhalogenated solvents, sufficient capacity exists to meet large scale
48 49
increases in demand for either type of solvent. ' Previous contacts
with manufacturers of refrigeration devices for vapor degreasing equipment
as well as contacts with cold cleaning manufacturers capable of processing
large production volumes indicate that sufficient capacity exists in both
sectors to meet significant increases in demand for either type of
equipment.28'29'30'50
2.4 ECONOMIC ANALYSIS OF SUBSTITUTES
2.4.1 Background
This section analyzes the economic feasibility of substituting
alternative cleaning processes for cold cleaning and vapor degreasing
operations that use trichloroethylene, perchloroethylene, methylene
chloride, 1,1,1-trichloroethane, trichlorotrifluoroethane, and carbon
tetrachloride. The substitutes analyzed are aqueous cleaning, emulsion
cleaning, nonchemical cleaning and cleaning with other organic solvents.
For the purposes of this study, the economic analysis deals only with
estimating the relevant costs of using substitutes. No attempt is made
to assess the user's ability to pay these costs. The cost categories
analyzed are costs related to a decline in product quality, and the
capital and annualized operating costs of using substitutes.
2-34
-------
2.4.1.1 Industry Structure
Metal cleaning is not a distinct industry, but rather it is part of
the production process utilized in most industries which manufacture,
maintain, and repair metal parts and products. These industries are
located throughout all geographic regions. The size of businesses which
clean or degrease metal parts and products range from small neighborhood
service stations to large plants, such as in the aircraft and automobile
industries. Table 2-5 illustrates the types of industries which use
metal cleaning operations in California.
2.4.1.2 Market Share of Substitutes
Aqueous cleaning, emulsion cleaning, nonchemical cleaning and
cleaning with solvents other than the halogenated solvents listed above
are all in present use. Figure 2-1 shows the market share of each substitute,
Of the four processes, aqueous cleaning systems, particularly alkaline
washers, are the primary substitute for vapor degreasing. Discussions
with respective manufacturers indicate that they are competing in the
14 15
same markets with their product. ' Table 2-3 shows the use of solvent
and alkaline cleaning systems by Standard Industrial Classification.
Overall, it is estimated that aqueous cleaning represents 39 percent of
52
the total metal cleaning market. Industries which use aqueous cleaning
to a large extent include metal furniture, fabricated products, and
transportation equipment.
Unlike aqueous cleaning systems, emulsion cleaners cannot be substituted
for halogenated solvents in as many given cleaning situations. This is
generally because of the need for a processed part that is devoid of any
surface oil or residue. Nevertheless, emulsion cleaners are frequently
used in metal cleaning operations, particularly when a chemically clean
surface is not required and when rust protection is a desired result of
the cleaning process. Approximately 15 percent of the metal cleaning
compounds used in this country are estimated to be solvent emulsions.
Of the four substitute cleaning methods identified, nonchemical
cleaning has the smallest market penetration. Nonchemical cleaning
systems are used principally to remove contaminants other than oils and
2-35
-------
TABLE 2-5. SUMMARY OF CERTAIN CALIFORNIA INDUSTRIES USING
SOLVENT CLEANING OPERATIONS51
SIC
332
342
344
346
347
349
351
356
359
366
367
369
371
372
376
Category
Iron & Steel Foundries
Cutlery, Handtools
Fabricated Structure
Metal Products
Forgings & Stampings
Metal Services
Misc. Fabricated Metals
Engines and Turbines
General Machinery
Misc. Machinery
Communicating Equipment
Electronic Components
Misc. Electrical
Motor Vehicles &
Equipment
Aircrafts & Parts
Guided Missies, Space
No.
of
companies
150
712
2,201
587
1,065
1,093
114
949
5,988
957
2,083
500
1,101
551
Percent of
companies
using
degreasing
37
25
5
4
55
18
100
45
33
48
40
33
45
60
No. of
companies
using
degreasing
56
178
110
23
586
197
114
427
1,996
459
833
167
495
331
Vessels
43
75
32
2-36
-------
AQUEOUS
CLEANING
(39%)
HALOGENATED
SOLVENT
CLEANING
(34%)
EMULSION
CLEANING
NONHALOGENATED
SOLVENT CLEANING
(24%)
NONCHEMICAL
CLEANING
(3%)
Figure 2-1. Market share of metal cleaning techniques.
52
2-37
-------
greases, such as corrosion products, heat scale, and carbon deposits.
Nonchemical cleaning can be used to clean internal combustion engine
parts prior to rebuilding and repair operations. This is one of the
few areas where substitution for halogenated solvents is possible. The
market penetration of nonchemical cleaning has been estimated to be less
52
than 3 percent.
Cleaning with organic solvents other than trichloroethylene, perchloroethylene,
methylene chloride, 1,1,1-trichloroethane, trichlorotrifluoroethane, and
carbon tetrachloride is predominantly done in cold cleaning systems,
except for trichlorofluoromethane which is a direct substitute in vapor
degreasing operations. However, because of the high volatility and cost
of trichlorofluoromethane relative to the chlorinated solvents, its use
is limited to specialty cleaning applications.
Nonhalogenated solvent cleaning operations make up approximately
52
24 percent of the total metal cleaning market. Cold cleaning solvents
include: acetone, cyclohexane, ethanol, isopropanol, methanol, methyl
ethyl ketone, petroleum solvents, toluene, and xylene. Table 2-6 shows
the percentages of halogenated and nonhalogenated solvents used in metal
cleaning operations.
2.4.1.3 Growth Trends
Growth in metal cleaning is directly related to the growth of those
industries in which it pays a prominent role. Table 2-7 lists the major
users of degreasing equipment according to expenditures. Since manu-
facturers of aqueous cleaning equipment and nonchemical cleaning equipment
compete in the same market, the data from Table 2-7 can be used as a
proxy for the projected growth of the substitutes. The number of cold
cleaners and vapor degreasers, respectively, is expected to grow by over
20 percent between 1980 and 1985. This is based on data supplied by the
Bureau of Labor Statistics which project average annual growth rates of
over 4 percent for industry groups using metal cleaning.
2-38
-------
TABLE 2-6. NATIONAL DECREASING SOLVENT CONSUMPTION53
Solvent type
Halogenated:
Trichloroethylene
1,1,1-Trichloroethane
Perchloroethylene
Methyl ene Chloride
Tri chl orotri f 1 uoroethane
Aliphatics
Aromatics:
Benzene
Toluene
Xylene
Cyclohexane
Heavy aromatics
Oxygenated:
Ketones:
Acetone
Methyl Ethyl Ketone
Alcohols
Ethers
Total Solvents
Solvent consumption,
Cold Vapor
cleaning degreasing
0.6 13.5
14.0 10.5
2.1 4.8
4.6 2.2
1.2 5.5
22.5 36.5
30.7
1.0
1.9
1.7
0.1
1.7
6.4
1.4
1.1
0.7
0.8
4.0
63.5 36.5
percent
All
degreasing
14.1
24.5
6.9
6.8
6.7
59.0
30.7
6.4
4.0
100.0
2-39
-------
TABLE 2-7. GROWTH TREND FOR DECREASING FOR SELECTED INDUSTRY GROUPS
a,54
Total
Standard degreaslng
Industrial cost - 1976
classification (10« $)
344 Fabricated Structural
Metal Products
354 Hetalworklng
Machinery
356 General Industrial
Machinery
359 Misc. Machinery,
Except Electrlal
372 Aircraft and Parts
382 Measuring and
Controlling Devices
458 Air Transport -
Maintenance
ix) 753 Auto Repair
S TOTAL
Incremental change
100
150
150
294
108
105
195
1,796
(«)
Number of .
cold cleaners
1976
25.131
38.152
30.734
79,547
11,967
17,797
36,160
468,027
707,515
1980
29,287
45,671
40,286
103,105
13,786
23,241
48,832
518,633
822.841
16.3
1985
35,291
52,689
55.195
118.948
17,594
26.943
66.278
627.969
1,000.907
21.6
Number of
open top
vapor degreasers
1976
771
569
1,876
1.085
2,779
3,194
3,279
0
13,553
1980
899
681
2.459
1.406
3.201
4.171
4,428
0
17,245
27.2
1985
1.083
786
3,369
1,622
4,086
4,835
6,010
0
21.791
26.3
Number of
conveyor) zed
degreasers
1976
187
122
402
232
393
187
0
0
1.523
1980
218
146
527
301
453
244
0
0
1.889
24.0
1985
263
168
722
347
578
283
0
0
2.361
24.9
Growth
ratec
1976-
80
3.9
4.6
7.0
6.7
3.6
6.9
7.8
2.6
1980-
85
3.8
2.9
6.5
2.9
5.0
3.0
6.3
3.9
These represent all Industrial groups using metal cleaning with expenditures in excess of $100 million in 1976.
Includes all cold cleaners using halogenated and nonhalogenated solvents.
GBureau of Labor Statistics estimated and projected growth rate.
-------
2.4.2 Product Quality
Product quality in metal cleaning is determined by the degree to
which a process satisfactorily cleans specific items. Costs associated
with a decline in product quality are the expenses associated with
re-cleaning an item. Generally, these expenses include additional energy
consumption, labor, cleaning material, and the opportunity cost of
foregoing cleaning new items while re-cleaning takes place.
2.4.2.1 Cold Cleaning With Halogenated Solvents Versus Alternatives
Automobile repair is the largest single industry group using cold
cleaning operations. Cold solvent usage may range from wiping a part
with a solvent soaked rag to the use of automated systems complete with
pump, filtration and distillation equipment, and auxiliary storage tanks.
Halogenated solvents are not used extensively in service and maintenance
sectors such as automotive repair due to their high cost, volatility, and
tendency of several to degrade painted surfaces. However, mixtures
containing halogenated solvents are employed in small maintenance cold
cleaners which are used to clean carburetors and other automotive parts.
One such mixture marketed by Safety-Kleen Corporation contains a blend of
methylene chloride, ortho-dichlorobenzene, and cresylic acid, covered by
55
an aqueous soap solution. The exact composition of solvent blends is
usually proprietary and is believed to vary from product to product and
from company to company.
Automotive repair operations generally do not require chemically
clean surfaces that halogenated solvents may provide. For this reason,
the use of an alternative organic solvent such as a petroleum solvent can
be used by this sector with no decline in product quality and consequently
no additional costs. The ability to chose between other organic solvents
is the principal form of substitution for this major user industry.
Depending upon the application, aqueous cleaning can also be used with
acceptable results although additional captial costs would be incurred by
those solvent users who do not possess cold cleaning equipment compatible
with aqueous cleaning media. The largest portion of these capital costs
would be for the acquisition of new cleaning equipment.
2-41
-------
There are certain critical cold cleaning operations for which there
are apparently no acceptable nonhalogenated solvent substitutes. These
critical cleaning applications involve certain electromechnical components.
Examples include some semi-conductor products; nuclear fuel handling
equipment; oxygen breathing apparati; precision medical equipment; and
fuel storage tanks for aerospace applications. In these applications,
halogenated solvents have a unique set of chemical and physical properties
required for such precise cleaning tasks. In such cases, substitution
with nonhalogenated solvents would likely cause a decline in product
quality such that costs arising from using a substitute could be prohibitive,
2.4.2.2 Vapor Degreasing Versus Alternatives
The primary substitute for vapor degreasing is alkaline washing. In
a 1978 study by Eureka Laboratories, Incorporated, cost data were compiled
from the comparative operations of a vapor degreaser and an alkaline
washer. Each system cleaned 100 metal cabinets weighing 100 pounds
apiece. It was estimated that 2 percent of the cabinets cleaned by the
alkaline washer were rejected and had to be re-cleaned. It was estimated
that re-cleaning cost four times the original cleaning expense. For this
specific case, the expense amounted to $9,390 (1978 dollars), approximately
10 percent of the total operating costs. The Eureka study also cited the
comparison of a vapor degreaser and an emulsion cleaner. The results
were generally the same as with the alkaline washer. Two percent of the
parts cleaned by the emulsion cleaner were rejected. Re-cleaning the
parts cost 4 times the original cleaning cost.
It must be noted, however, that the above comparisons represent
case-specific tests which may not reflect current technology. Similar,
more recent tests have not been conducted. Because alkaline washer
manufacturers often custom-build their systems for a specific cleaning
need, it is unlikely that costs associated with a decline in product
quality would prohibit substitution.
2-42
-------
2.4.3 Capital and Annualized Operating Costs
2.4.3.1 Alternatives to Cold Cleaning With Halogenated Solvents
The main technically and economically feasible alternative to cold
cleaning with trichloroethylene, perch!oroethylene, methylene chloride,
1,1,1-trichloroethane, trichlorotrifluoroethane, or carbon tetrachloride
is cold cleaning with other solvents, such as mineral spirits. Of the
six halogenated solvents investigated, 1,1,1-trichloroethane is used most
often in cold cleaning operations. In 1979, it was estimated that 115,000 megagrams
115,000 megagrams (127,000 tons) of 1,1,1-trichloroethane was used in
this manner (see Table 2-2).
By converting to other organic solvents, no capital charges would be
incurred. In addition, actual operating costs could be reduced because
of the lower price and evaporative rates of other solvents. Emissions
from a typical cold cleaning operation would be reduced from 740 kg/yr
to 100 kg/yr by converting from 1,1,1-trichloroethane to mineral spirits. This
would result in an annual savings of $450 per unit.
An alternative to converting to other organic solvents is to use
aqueous cleaning systems in the same dip tank as the halogenated solvents.
Although design requirements on some units may prohibit such conversion,
many cold cleaner manufacturers make units which can use either solvent or
aqueous systems. One such manufacturer is Economics Laboratory, Incorporated.
In addition to solvent cleaning, Economics Laboratory's machines are used
for alkaline cleaning, derusting, stripping, and phosphatizing.45
By converting from 1 ,1,1-trichloroethane to an aqueous solution,
additional costs of approximately $1,100 per year could be incurred for an
average size cold cleaner. This cost is based on chemical cost and
solution lifetime with no additional equipment costs to implement substitution.
This is a worst case situation, assuming that the aqueous solution is
replaced every 20 work days.3 In a year's time, 5,300 liters of solution,
worth $1,580 would be consumed. In the same time frame, 740 kg of halogenated
solvent would be consumed, worth $500. If the aqueous solution was
replaced once every 9 months, only $160 worth of solution would be consumed,
saving $340.
Replacement of aqueous solutions range from 20 days to 9 months.
2-43
-------
2.4.3.2 Vapor Degreasing and Alternatives
• Vapor degreasing versus alkaline washing—Several studies comparing the
cost of vapor degreasing to alkaline washing have been completed in the
past ten years. In one study, Eureka Laboratories, Incorporated,
building upon earlier work done by the American Society for Metals
(ASM), compared an open top vapor degreaser to an alkaline washer.
Each system cleaned 100 pound steel cabinets at the rate of 100 per
hour. A comparison of costs between the two systems is presented in
Table 2-8.
Table 2-8 shows that capital and operating costs were higher for the
alkaline washer. The annualized capital cost for the alkaline washer
was $17,330, almost twice the annualized capital cost of $9,140 for
the vapor degreaser. The cost difference is attributed to higher
equipment costs and greater building space requirements for the
alkaline washing systems. The annual operating costs for vapor
degreaisng were $54,780 while the annual operating costs for the
alkaline washer were $72,220. The greater annual operating costs for
the alkaline system can be attributed primarily to the cost of
utilities, such as gas for heating water and air, and the cost for
rejects handling. The cost for rejects handling represents a product
quality cost. When the total annualized costs for the two systems are
compared, alkaline washing was shown in this test to be about 40 percent
more costly than vapor degreasing.
• Conveyorized vapor deqreasing versus alkaline washing—Another study,
performed by Dow Chemical Company at a General Motors plant in Grand
Rapids, Michigan, compared a vibra degreaser (a type conveyorized
vapor degreaser) to a spiral alkaline washer. The results of this
study, cited by Eureka Laboratories, Incorporated are presented in
Table 2-9. In the test, diesel equipment parts were cleaned by each
system. The annualized capital costs for the vapor degreaser are
$10,080, or about 35 percent higher than the annualized capital costs
of $6,460 for the spiral washer. This difference in annualized
capital costs is due primarily to the higher equipment cost for the
vapor degreaser. The annual operating costs for alkaline washing are
$26,360, about 32 percent higher than the annual operating costs of
$19,910 for the vapor degreaser. The difference in annual operating
costs is due primarily to greater material and steam costs per year
for the alkaline washing system. The total annualized costs (the sum
of annualized capital charges and annual operating costs) for
conveyorized vapor degreasings are $29,990, about 12.5 percent less
than the total annualized costs of $33,820 for alkaline washing.
• Vapor deqreaser versus alkaline washing—Results of tests comparing
vapor degreasing and alkaline washing were reported by Hamilton Standard
to EPA's Effluent Guidelines Division in 1979. The analysis was
normalized on a cost per thousand square foot basis. The tests show
that alkaline washing requires a 71 percent greater capital outlay for
equipment and related items than the vapor degreaser. In the vapor
degreasing system, solvent costs accounted for 86 percent of the
2-44
-------
TABLE 2-8. COMPARISON OF COSTS FOR VAPOR DECREASING
AND ALKALINE WASHING ($)58
Item
Capital costs
Equipment
Installation
Building space
50% indirect
Insurance
Operating costs
Direct labor
Material
Utilities
Water
Steam
Electricity
Gas
Maintenance
Labor
Parts
Rejects handling
Overhead
Total annual i zed cost
Vapor
degreasing
Absolute Annual ized
52,800
7,900
60,700 7,130
4,920
2,460
7,380 810
1,200
9,140
17,500
22,740
50
4,170
160
--
3,500
1,410
--
5,250
54,780
63,920
Alkaline
washing
Absolute Annual ized
70,400
10,600
81,000 9,520
32,800
16,400
49,200 5,420
2,390
17,330
17,500
7,580
--
--
1,120
24,000
5,000
2,000
9,390
5,630
72,220
89,550
2-45
-------
TABLE 2-9. COMPARISON OF COSTS FOR CONVEYORIZED
DECREASING AND ALKALINE WASHING (S)59
Conveyorized Alkaline
degreasing washing
Capital costs
Equipment
Instal lation
Building space
50% indirect
Annual capital charges
Equipment & installation
Building space
Insurance
Annual operating costs
Maintenance (labor, parts)
Material
Steam
Water
Wastewater treatment
Electricity
Make-up air heat
Residue disposal
Total annual cost
Cost/metric ton of metal cleaned
62,380
9,360
2,090
1,040
8,430
340
1,310
5,980
6,780
4,770
590
0
570
0
1,220
42,920
6,440
4,130
2,070
5,800
680
980
10,080
4,000a
9,230
11,780
13
58
950
330
0
19,910
29,990
6.00
7,460
26,360
33,820
6.76
aAssume $2,380/year as the cost for parts.
2-46
-------
operating costs. This was counterbalanced by the higher energy costs
with the alkaline system such that total operating costs varied by
less than 2 percent. This indicates relative parity between the
two systems.
Comparison of Hamilton Standard Data and Dow Chemical Data—The Hamilton
Standard data and the Dow Chemical data are presented for comparison in
Table 2-10. The data are normalized on a cost per thousand square foot
basis. The capital charges in the Dow study are $5.08 for vapor degreasing
and $5.78 for alkaline cleaning. These costs show that capital charges
for alkaline cleaning are about 14 percent higher than vapor degreasing
costs. The Hamilton Standard data show the capital charges for vapor
degreasing as $2.34 and for alkaline cleaning as $4.01. This study
shows that the capital charges for alkaline washing are about 71 percent
greater than for vapor degreasing. The difference in capital charges
for vapor degreasing and alkaline washing between the two studies is
attributed to a greater difference in equipment costs for vapor degreasing
and alkaline washing in the Hamilton Standard study than the Dow Chemical
study.
The operating costs in the Dow study are $13.11 per thousand square
feet for vapor degreasing and $14.91 for alkaline washing. These costs
again show that operating costs for alkaline washing are about 14 percent
greater than operating costs for vapor degreasing. In the Hamilton
standard study, the operating costs are $11.04 for vapor degreasing and
$11.26 for alkaline washing. These data show that operating costs for
alkaline washing are about 2 percent greater than the operating costs
for vapor degreasing.
The Dow Chemical data show total costs of $18.19 for vapor degreasing
and $20.69 for alkaline washing. These data show that alkaline washing
costs $2.50 more per thousand square feet than vapor degreasing, or
about 14 percent more than vapor degreasing. The Hamilton Standard
data show total costs of $13.38 for vapor degreasing and $15.27 for
alkaline washing, a difference of $1.89 per thousand square feet per
year. These data indicate total costs for alkaline washing are about
14 percent greater than the total costs for vapor degreasing.
Both the Dow and the Hamilton Standard studies conclude that the total
cost for alkaline washing is about 14 percent greater than the total
cost for vapor degreasing. The Hamilton Standard study, however,
attributes most of the total difference in cost to a greater difference
in equipment costs between vapor degreasing and alkaline washing than
the Dow Study.
Vapor Degreasing versus Emulsion Cleaning—Eureka Laboratories, Incorporated,
compiled comparative cost data for vapor degreasing and emulsion cleaning
from a test in which both processes were used to clean aluminum alloy
reflectors weighing four pounds each. Table 2-11 presents the results
of the tests.
2-47
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TABLE 2-10.
COST COMPARISON BASED ON ACTUAL DATA:
VERSUS ALKALINE WASHING60
(Cost per thousand square feet)
VAPOR DECREASING
Equipment
Building
Insurance
Maintenance
Chemicals
Steam
Electric power
Water
Waste treatment
Make-up air heat
TOTALS
Dow Chemi
Vapor
degreaser
4.26
0.16
0.66
5.08
5.08
4.32
2.68
0.49
0.54
Neg.
--
13.11
18.19
cal data
Al kal ine
cleaner
4.53
0.49
0.76
5.78
0.66
6.61
5.63
1.31
Neg.
0.54
0.16
14.91
20.69
Hamilton Standard
Vapor
degreaser
1.96
0.06
0.32
2.34
0.90
9.49
0.60
0.05
Neg.
Neg.
—
11.04
13.38
data
Alkal ine
cleaner
3.28
0.21
0.52
1.22
3.93
5.13
0.55
0.14
0.15
0.14
4.01
11.26
15.27
2-48
-------
TABLE 2-11. COMPARISON OF COSTS FOR VAPOR DECREASING
AND EMULSION CLEANING ($)61
Item
Capital costs
Equipment
Installation
Building space
50% indirect
Insurance
Operating costs
Direct labor
Material
Utilities
Water
Steam
Electricity
Gas
Maintenance
Labor
Parts
Rejects handling
Overhead
Total annual ized cost
Vapor
degreasing
Absolute Annual ized
32,300
4,840
37,140 4,360
3,280
1,640
4,920 540
740
5,640
17,500
11,340
30
1,490
160
--
2,000
1,160
--
4,880
38,560
44,200
Emu! si on
cleaning
Absolute Annual ized
49,900
7,480
57,380 6,740
13,670
6,830
20,500 2,100
1,410
10,250
17,500
4,250
--
--
670
8,800
2,000
2,320
3,010
4,880
43,430
53,680
2-49
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Annualized capital charges are $5,640 for vapor degreasing and $10,250
for emulsion cleaning. The annualized capital charges for emulsion
cleaning are about 82 percent greater than the annualized capital
charges for vapor degreasing. This difference is attributable
primarily to greater costs for equipment and building space for the
emulsion cleaning system.
Annual operating costs are $38,560 for vapor degreasing and $43,430 for
emulsion cleaning, representing about a 12 percent difference in cost.
The vapor degreasing operation shows a $7,090 greater annual cost for
materials than emulsion cleaning. However, emulsion cleaning shows an
annual cost of $8,800 for gas for heating and an annual cost of $3,010
for rejects handling while vapor degreasing shows no cost for either of
these items.
• Vapor Degreasinq with Trichlorofluoromethane (CFC-11)--CFC-ll is a
technical substitute for trichloroethylene, 1,1,1-trichloroethane,
methylene chloride, and trichlorotrifluoroethane in vapor degreasing.
However, the use of CFC-11 historically has been restricted to a few
specialized cold cleaning operations. Two reasons for its limited use
are its high volatility and its potential to deplete stratospheric
ozone.
Using CFC-11 in vapor degreasing requires retrofitting an existing
degreaser with a refrigerated freeboard device to prevent excessive
solvent losses. A capital outlay ranging from $6,200 to $13,000 (depending
upon the size of the degreaser) would be required to install this
device.61 The impact on annualized costs would vary depending
on the solvent which CFC-11 replaces. While the use of a refrigerated
freeboard device would reduce total solvent emissions, variations in
solvent price ($0.60/kg for trichloroethylene to $1.04/kg for CFC-11)
prohibit the inference that net annualized operating costs would be
less with CFC-11.
In conclusion, CFC-11 can be viewed as a technically feasible substitute.
Data is insufficient to completely assess its economic feasibility, but
evidence suggests there are instances where the capital outlay associated
with its use can be offset by a net solvent savings. This would occur
,vhen the recovered value of the solvent is greater than the cost of the
emission control. However, due to the ozone depletion question,
environmental regulatory policy may be the most salient factor
affecting the use of CFC-11 as a substitute.
2.5 CONCLUSIONS AND RECOMMENDATIONS
Due to the diversity of the process variables, alternatives to the
use of these solvents may not exist in every cleaning operation and the
choice among relatively comparable cleaning methods will not always be
predicated on economic grounds. There is strong evidence indicating that
2-50
-------
in many industrial processes metal cleaning is not designated as a cost
center for accounting purposes. Metal cleaning is often included in the
"overhead" category such that a significant number of users of solvent
metal cleaning in all industries do not tend to regard cleaning expenditures
as critical investment decisions. Given these factors, the large-scale
economic impacts arising from substitution are difficult to ascertain.
However, the data presented in this analysis provide certain insights
into the technical and economic feasibility of solvent substitutes for
metal cleaning. First, cost and effectiveness comparisons continue to be
performed, especially between vapor degreasing and alternative systems.
These tests indicate interchangeability between these is often feasible.
This is also underscored by the view of solvent and aqueous cleaning
equipment manufacturers that they are competing in the same industrial
markets. Second, research and development by both aqueous washing and
cleaning compound manufacturers has increased steadily. The goal is to
provide aqueous cleaning systems to industry that are functionally equivalent
and cost competitive to solvent-based systems. This trend is important
because the comparative cost data presented in the economic analyses
indicate that higher energy consumption is the primary reason why aqueous
cleaning systems demonstrate higher operating costs than vapor degreasers.
Recognizing that reductions in the energy consumption of aqueous cleaning
equipment can close the cost gap between these systems, several major
manufacturers of aqueous cleaning chemicals have formulated compounds
capable of achieving a high level of cleaning efficiency at substantially
lower operating temperatures than have previously been employed (83°C
?7 fi?
down to approximately 20°C). ' Further technological refinements on
the part of aqueous washer manufacturers is acting to close the cost gap
between aqueous and solvent cleaning systems. For example, one major
manufacture of aqueous cleaning equipment reports development of "closed-loop"
alkaline washing systems which will reduce energy consumption, substantially
reduce effluent and effluent treatment cost, and provide a resource
recovery mechanism which will reduce the time required for capital recovery.
2-51
-------
Data from comparative studies between cold solvent and vapor degreasing
systems and alternative systems have shown solvent systems historically
to be less costly to operate. However, in most applications there is
relative parity in the degree of cleaning effectiveness. Additionally,
evidence shows that the trend is toward greater capital and operating
parity, at least between vapor degreasing and aqueous cleaning systems.
Technological innovations, particulary in the area of reduced energy
consumption may play a major role in increasing both the technical and
economic feasibility of using substitutes for solvents in metal cleaning.
Generalizations concerning industry-wide ability to implement alternative
cleaning methods for those using halogenated solvents are complicated by
limited and often dated information. In order to determine more fully if
substitution of the alternative methods examined in this analysis
represent viable choices for the majority of solvent users, research is
needed to supplement existing data in a number of areas. The results of
this research can be used to develop model cost data based on engineering
and accounting analyses for the purpose of estimating the approximate
costs of substitution for a selected cross-section of different type and
size solvent users; identify historic trends in the use of alternative
cleaning methods in relation to solvent cleaning; determine the market
structure of and for solvent substitutes; investigate the extent to which
capital budgeting decisions of solvent users are affected by the availability
of substitute cleaning methods and uncertainties in the regulatory environment
regarding solvents; calculate any added costs to consumers; and estimate
the impacts on solvent producers under varying levels of substitute
usage.
2-52
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2.6 REFERENCES
1. U.S. Environmental Protection Agency. Materials Balance Summaries
for Trichloroethylene, Perchloroethylene, 1,1,1-Trichloroethane,
Methylene Chloride, and Trichlorotrifluoroethane. Office of Toxics
Integration. Washington, DC. August 1981.
2. U.S. Environmental Protection Agency. Organic Solvent Cleaners -
Background Information for Proposed Standards (EPA-450/2-78-nd5a)
Office of Air Quality Planning and Standards. Research Triangle
Park, NC. October 1979. p. 8-23. (growth factors applied to
estimate 1980 levels).
3. Personal Communication. Terry O'Brian, GCA Corporation with J. Otrhalec,
Detrex Chemical Industries, Detroit, MI. September 22, 1981.
4. Springs, S. Cleaning and Detergency. Metal Finishing. November 1974.
p. 59.
5. Spencer, L.F. The Cleaning of Metals: Part 1-Alkaline Cleaning.
Metal Finishing. April 1962. p. 59-60.
6. ASM Committee on Selection of Cleaning Processes. Selection of
Cleaning Processes, Metals Handbook. The American Society for
Metals, Cleveland, Ohio. Vol. 2, p. 307.
7. Leung, S. et al. Alternatives to Organic Solvent Degreasing.
Eureka Laboratories, Incorporated. Sacramento, California. May 1978.
pg. 75.
8. Reference 5, pps. 60-61.
9. Springer, S. Chemical Used in Industrial Cleaning. Metal Finishing
December 1974. p. 36.
10. Personal Communication. Terry O'Brian, GCA Corporation with
Dennis Willis, Economics Laboratory, Incorporated, St. Paul, MN.
December 29, 1981 .
11. Letter and attachments from Westray, W.K, to U.S. Environmental
Protection Agency, Central Docket Section, Docket No OAQPS-78-12.
October 24, 1980. pg. 6. Comments on Proposed Standards of Performance
for Organic Solvent Cleaners.
2-53
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12. Kleer-Flo Parts Washer and Cleaning Solution Catalogue. Kleer-Flo
Company, Eden Prairie, Minnesota. March 1980. p. 1-12.
13. Surprenant, K.S. and D.W. Richards, Study to Support New Source
Performance Standards for Solvent Metal Cleaning Operations. U.S.
Environmental Protection Agency, Office of Air Quality Planning and
Standards, Research Triangle Park, North Carolina. EPA Contract
Number 68-02-1329, Task Order Number 9, June 30, 1976. p. 17.
14. Personal Communication. Terry O'Brian, GCA Corporation with Graham
Pendleton, Kleer-Flo Company, Eden Prairie, MN. November 2, 1981.
15. Personal Communication. Terry O'Brian, GCA Corporation with Dennis Willis,
Economics Laboratory, Incorporated, St. Paul, MN, November 9, 1981.
16. Personal Communication. Terry O'Brian, GCA Corporation with
Lyle Carmen, Ransohoff Corporation, Hamilton, OH. November 13, 1981.
17. Briggs, J.L. et al.. A Comparative Study of Aqueous and Solvent
Methods for Cleaning Metals. U.S. Energy Research and Development
Administration, Albuquerque Operations Office, Albuquerque, New
Mexico. ERDA Contract Number E(29-2)-3533, April 1976.
18. Personal Communication. Terry O'Brian, GCA Corporation with Jim Dingman,
Pack Industries, Incorporated, Greensboro, NC. November 16, 1981.
19. Letter from Art Gillman, Unique Industries, Inc. Sun Valley, CA to
Richard Rehm, GCA/Technology Division. February 8, 1983.
20. Wagner, L.K. Organic Surface Contimination - Its Identification,
Characterization, Removal, Effects on Insulation Resistance and
Conformal Coatings Adhesion. Institute for Interconnecting and
Packaging Electronic Circuits. Evanston, IL. September 1981.
21. Personal Communication. Terry O'Brian, GCA Corporation with Steve Temple,
Ransohoff Incorporated, Hamilton, OH. November 5, 1981.
22. Personal Communication. Terry O'Brian, GCA Corporation with Paul Salz,
Unique Industries, Incorporated, Sun Valley, CA. December 12, 1981.
23. Personal Communication, Terry O'Brian, GCA Corporation with Frank Barr,
Graymills Incorporated, Chicago, IL. November 2, 1981.
24. Personal Communication. Terry O'Brian, GCA Corporation with Lyle Carmen,
Ransohoff Incorporated, Hamilton, OH. November 17, 1981.
25. Personal Communication. Terry O'Brian, GCA Corporation, with Grady Rorie,
General Motors Corporation, Warren, MI. November 30, 1981.
26. Reference 13, p. 4-29.
2-54
-------
27. Personal Communication. Terry O'Brian, GCA Corporation with John Sparks
DuBois Chemical Company, Cincinnati, OH. November 18, 1981.
28. Personal Communication. Terry O'Brian, GCA Corporation with Lyle Carmen
Ransohoff Incorporated, Hamilton, OH. April 22, 1982.
29. Personal Communication. Terry O'Brian, GCA Corporation with Graham Pendleton
Kleer-Flo Company, Eden Prairie, MM. April 22, 1982.
30. Personal Communication. Terry O'Brian, GCA Corporation with Dennis Willis
Economics Laboratory, Incorporated, St. Paul, MM. April 22, 1982.
31. Spencer, L.F. The Cleaning of Metals: Part 3-Emulsion and Diphase
Cleaning. Metal Finishing, June 1963. p. 85.
32. Reference 7, p. 92.
33. Connolly, J.T. Metal Cleaning with Emulsions - An Update. Journal of
the Society of Lubrication Engineers. December 1976. pps. 651-654.
34. Graymills Parts Washer and Cleaning Solution Catalogue Number GM 65R-6
Graymills Corporation, Chicago, Illinois. May 1978. p. 1-16.
35. Glover, H.C. Are Emulsified Solvents Safer Cleaners? Production
Engineering. July 1978. p. 41-43.
36. Reference 33, p. 651.
37. Reference 33, p. "53.
38. Metal Finishing and Surface Preparation. Equipment specification sheet
Number 513-56. Inland Manufacturing Company, Omaha, Nebraska. June 1977.
39. Lyman, T ed., Blast Cleaning of Metals. Metals Handbook. The American
Society for Metals, Cleveland, Ohio, 1948. p. 300-301.
40. Personal Communication. Terry O'Brian, GCA Corporation with Peter Hoezel ,
Inland Manufacturing Company, Omaha, NB. December 11, 1981.
41. Handbook of Industrial Blasting: Section 1 - Automotive Parts Cleaning
Inland Manufacturing Company, Omaha, Nebraska. 1972. p. 1-9.
42- P^SOf]al Interview- Terry O'Brian, GCA Corporation with Hank Osterman,
Allied Corporation, Morristown, NJ. October 28, 1981.
43. Physical Properties of Common Organic Solvents and Chemicals. Chemcentral
Corporation. Chicago, Illinois. 1980. ps. 1-4.
44. Chemical Marketing Reporter, Schnell Publishing Company, New York, NY,
March 31,1 981 .
2-55
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45. Mangus Cleaning and Processing Equipment Catalouge. Economics
Laboratory, Incorporated, St. Paul, Minnesota. 1979. p. 5.
46. Reference 43, p. 3.
47. Tang, J.L. Industrial Survey of Halogenated Solvent Producers and
Degreaser Manufacturers. GCA/Technology Division. July 1981.
48. Personal Communication. Terry O'Brian, GCA Corporation with
Hank Osterman, Allied Corporation, Morristown, NJ. December 30, 1981.
49. Personal Communication. Samuel Duletsky, GCA Corporation with
Jim Watson, Getty Refining and Marketing Company, Tulsa, OK.
November 4, 1981.
50. Personal Communication. Terry O'Brian, GCA Corporation with
Burton Rand, AutoSonics, Incorporated, Norristown, PA. June 13, 1981.
51 . Reference 7, p. 90.
52. O'Brian, T. Estimation of Market Share of Metal Cleaning Techniques,
GCA/Technology Division, Chapel Hill, North Carolina. December 1981.
53. U.S. Environmental Protection Agency. Control of Volatile Organic
Emissions from Solvent Metal Cleaning, EPA-450/2-77-022. Office of
Air Quality Planning and Standards, Research Triangle Park, North
Carolina. November 1977. p. 2-5.
54. Reference 2, pps. 8-17 and 8-23.
55. Letter from Ted Mueller, Safety-Kleen Corporation, to Richard Rehm,
GCA/Technology Division, October, 1980.
56. Graymills Equipment Price List Number GMPL-20. Graymills Corporation
Chicago, Illinois, April 1981. pp. 1-4.
57. Erickson, P.R. and W.M. Throop. Improved Washing of Machined Parts.
Production Engineering. March 1977. pp. 55-57.
58. Reference 7, p. 146.
59. Reference 7, p. 157.
60. Bauks, S.V. and K.J. Dresser. Cleaning Alternative to Organic Solvent
Degreasing. Technical report prepared for the U.S. Environmental
Protection Agency, Effluents Guideline Division, Washington, D.C.
December 1979. pp. 1-12.
61 . Reference 11, p. 149.
62. Personal Communication. Terry O'Brian, GCA Corporation with Dennis
Forian, Oakite Products, Incorporated, Berkeley Heights, NJ.
November 19, 1981.
2-56
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3.0 DRY CLEANING INDUSTRY
3.1 GENERAL DESCRIPTION OF USE
3.1.1 Process Description
Dry cleaning is a process in which organic solvents, rather than
detergent and water, are used to clean clothing and other articles. The
principal steps in the process are identical to those of laundering in
water. In the first step, clothes are loaded into the washer and solvent
is added. The clothes and solvent are then agitated by the turning
motion of a paddle or wheel. After washing is completed, the clothes are
spun as in a conventional washer spin cycle to extract the solvent.
After extraction, the used solvent is filtered and distilled to remove
impurities and is then returned to the system. After solvent wash and
extraction, the clothes are tumbled dry. During the drying cycle, the
evaporated solvent is either recovered in a condenser and returned to the
system or vented to the atmosphere. Solvent remaining in the clothes is
reduced by venting ambient air through the clothes. This last process is
referred to as aeration or deodorization.
There are two basic types of dry cleaning machines: transfer
machines and dry-to-dry machines. Transfer machines are those in which
washing and drying are performed in different machines. After washing
and extraction, the fabrics are transferred to the dryer. Dry-to-dry
machines are those in which washing and drying occur in a single unit.
Three solvent types are used in the dry cleaning industry:
perchloroethylene (perc), trichlorotrifluoroethane (CFC-113) and petroleum
solvents. Of these three solvents, perchloroethylene is preferred by
most users. Perchloroethylene is nonflammable, has excellent solvent
properties, does not damage apparel, can be used in transfer machines and
dry-to-dry machines, and is comparable to petroleum solvents on a
performance or production basis. Because of its high cost CFC-113 is
3-1
-------
used only by a small percentage of dry cleaners. However, its nonflammability,
rapid low temperature drying characteristics, gentle solvent properties,
and low toxicity make CFC-113 an alternative to perch!oroethylene and
petroleum solvents.
About 30 percent of the total quantity of clothes cleaned by the dry
cleaning industry are cleaned using petroleum solvents. Petroleum solvents
are mixtures of paraffins and aromatic hydrocarbons that are similar to
kerosene. In the past, petroleum solvents were much less expensive than
perchloroethylene. However, at present, petroleum solvents and perc are
priced competitively. A recent trend has been to substitute to perc for
petroleum solvents. Table 3-1 lists the physical properties of several
types of petroleum solvents used in dry cleaning.
The machines and operating procedures used in dry cleaning vary with
the type of dry cleaning solvent used. Petroleum solvents are combustible
while halogenated solvents, perc and CFC-113, are nonflammable. Therefore,
petroleum solvent machines are specially designed to be explosion-proof,
while perc and CFC-113 machines require no such special design. All
petroleum solvent dry cleaners use transfer type machines to reduce the
risk of fire and explosion. Perc can be used in either transfer machines
or dry-to-dry machines. Machines using CFC-113 are all of the dry-to-
dry type. Machines used to dry articles washed in perc or CFC-113 are
usually equipped with a condenser and a carbon adsorber to capture vapors
as they leave the dryer. Petroleum dryers typically vent the volatilized
solvent stream directly to the atmosphere without any type of solvent
recovery. However, petroleum dryers fitted with condensers to remove
petroleum solvent from the dryer exhaust are currently manufactured and
sold in the United States. This type of dryer is called a recovery
dryer. A schematic of a perc dry cleaning plant is shown in Figure 3-1.
A typical petroleum solvent dry cleaning plant is shown in Figure 3-2.
Because of these characteristics, DuPont stated that CFC-113 should not
be equated with perchloroethylene in this analysis (see Appendix A)
3-2
-------
TABLE 3-1. PHYSICAL PROPERTIES OF PETROLEUM DRY CLEANING SOLVENTS'
OJ
I
OJ
Chevron
Property
Flash point (°F)
Initial BP (°F)
Dry end point (°F)
Specific gravity 0 GOT
Heat of vaporization (Btu/lb)
Average molecular weight
TLV (ppm)
Aromatics content (%V)
Naphthenes content (%V)
Paraffins content (XV)
325
101
316
366
0.784
119
138
250
2
67
31
450
146
363
477
0.809
108
166
275
2
62
36
Shell
Mineral
spirits
140
113
332
392
0.786
-
-
-
12
44
44
AMSCO
Mineral
spirits
105
312
390
0.786
-
-
-
17
36
47
Ashland
Kwik Dri
103
315
360
0.750
104
130
500
3
35
62
Inland Oil
Stoddard
108
324
390
0.784
-
_
200
12
44
44
140-F
143
364
399
0.784
_
_
175
9.5
45
45
denotes data unavailable.
-------
EXHAUST GAS/SOLVENT
CO
I
DETERGENT
MUCK
GASES
SOLVENT
EMISSIONS
HEATED AIR
FILTERED
SOLVENT
DISTILLATION
BOTTOMS
SOLVENT
SEPARATOR
CONDENSER
Figure 3-1. Perchloroethylene dry cleaning plant flow diagram.'
-------
SPENT SOLVENT
-»
FILTER
NEW SOLVENT IN
FILTERED SOLVENT
FILTER WASTE
TO DISPOSAL
FILTER WASTE
SOLVENT REMOVER
VENT OR CENTRIFUGE
FILTER
WASTE
NEW AND
REGENERATED
SOLVENT
STORAGE TANK
DISTILLED SOLVENT
X
VENT
FILTERED
SOLVENT
TANK
CONDENSER
BOILING
CHAMBER
SOLVENT I
VACUUM ' ^
STILL STILL WASTE
TO DISPOSAL
LEGEND
SOLVENT FLOW
VAPOR EMISSION
SOLID WASTE EMISSION
o
DRYER
Figure 3-2. Petroleum solvent dry cleaning plant flow diagram.
3-5
-------
3.1.2 Industry Characterization
The dry cleaning industry is subdivided according to the type of
solvent used and the type of services offered. As previously mentioned,
three solvent types are used in the dry cleaning industry: petroleum
solvents, perc, and CFC-113. The industry is also composed of three
sectors which are delineated by the type of services offered: the self-service
or coin-operated sector; the commercial dry cleaning sector; and the
industrial dry cleaning sector. Coin-operated dry cleaning facilities
are usually, but not necessarily, part of a "laundromat" facility and
operate either on an independent or franchise basis. Commercial dry
cleaning plants are the most familiar type of facilities, offering the
normal services of cleaning soiled apparel or other goods. They include
small neighborhood dry cleaning shops operating on an independent basis,
franchise dry cleaning shops, and speciality cleaners which handle leather
and other fine fabrics. The largest dry cleaning plants and cater to
industrial, professional, and institutional customers. Articles such as
mats, mops, rugs, and work uniforms are cleaned by industrial dry cleaners,
often in conjunction with rental operations. The estimated percentage of
dry cleaning operations using solvents in each of the three categories in
which the industry can be segregated is shown in Table 3-2.
TABLE 3-2. ESTIMATED NUMBERS OF DRY CLEANING OPERATIONS AND SOLVENT
USAGE IN THE UNITED STATES1'7'8'9
Type of
operation
Coin-operated
Commercial
Industrial
Number of
operations
11,800-18,000
25,000
920- 1 ,000
Percent using
perchloroethylene
97.5
73
75
Percent using
CFC-113
2.5
3
0
Percent using
petroleum
solvents
0
24
25
3-6
-------
As shown in Table 3-2, all coin-operated dry cleaning operations use
either perc or CFC-113. The use of petroleum solvents by coin-operated or
self-service dry cleaning plants is prohibited by National Fire Protection
codes due to the highly volatile and flammable nature of petroleum solvents.10
Table 3-2 also shows that 75 percent of industrial dry cleaning
establishments use perc and 25 percent use petroleum solvents. This may be
misleading however, since 50 percent of the total weight of clothes dry
cleaned by industrial plants are cleaned with perc and 50 percent with
petroleum solvents. The industrial dry cleaners that use petroleum solvents
generally have larger machines than those which use perc, thus allowing them
to clean more clothes per plant per year.
In 1979, 211,000 megagrams (233,000 tons) of perch!oroethylene and
1,670 megagrams (1,850 tons) of CFC-113 were used in the dry cleaning
industry. About 136,000 megagrams (150,000 tons) of petroleum solvents
were used.
3.2 DISCUSSION OF SUBSTITUTES
For an organic solvent to be acceptable as a dry cleaning solvent, the
solvent should possess the following properties: the solvent must neither
weaken nor shrink ordinary textile fibers; the solvent must not bleed common
dyes from such fibers; it must have the ability to remove fats and oils; it
should not impart objectionable odors to textiles; and it should not be
corrosive to metals. 3 Petroleum solvents possess these characteristics to
the degree that they can be considered proven dry cleaning agents as
substitutes for perc and CFC-113. Several other solvent mixtures possess
these characteristics to the degree that they can be considered potential dry
cleaning agents.
At the present time, petroleum solvents account for slightly less than
30 percent of the annual national dry cleaning throughput. Dry cleaning
patents have been issued for tetrachlorodifluoroethane, 1,2,-dichloroethylene,
hexafluorodichlorobutene, and quaternary azeotropes based on tetrachloro-
difluoroethane, but these solvents are presently not known to be used in the
dry cleaning industry. Representatives of the major dry cleaning trade
organizations were contacted to determine the extent of use of these solvents
in the dry cleaning industry, but none of the representatives claimed any
3-7
-------
knowledge of the use of these solvents in dry cleaning. ' Tests
performed on these solvents indicate that they may have some value as dry
cleaning solvents, but not enough information is available to present a
detailed analysis of the technical and economic feasibility of using them as
substitutes for perc and CFC-113.13
The only solvents for which information about the technical and economic
feasibility of substitution is readily available are petroleum solvents.
Petroleum solvents are the only solvents other than perc and CFC-113 used in
14
dry cleaning today. Because perc is used to clean 70 percent of the annual
national dry cleaning throughput and CFC-113 is used to clean less than one
percent, this section addresses the feasibility of substituting petroleum
solvents for perc. The information presented generally applies to the
substitution of petroleum solvents for CFC-113.
3.3 TECHNICAL ANALYSIS OF SUBSTITUTES
This section analyzes the technical factors influencing the substitution
of petroleum solvents for perc in dry cleaning plants. The factors analyzed
are the method of substitution, the impact that fire codes may have on
substitution, the degree to which petroleum solvents can be substituted for
perc based on product quality, and the availability of petroleum solvents and
petroleum solvent dry cleaning equipment.
3.3.1 Method of Substitution
The only method of substituting petroleum solvent for perc is to replace
the perc dry cleaning equipment with petroleum solvent dry cleaning equipment.
This replacement is necessary because petroleum solvents must be used in
machines that are specially designed to be explosion-proof, and perc machines
are not designed as such. The major pieces of equipment that must be replaced
are the washer, dryer, solvent still, and solvent storage tank.14
The replacement of perc dry cleaning equipment with petroleum dry
cleaning equipment is feasible because petroleum washers, dryers, stills,
and storage tanks are about the same size as those used in perc dry cleaning.
In addition, petroleum washers, dryers, and stills require the same connections
for electricity and steam as perc washers, dryers, and stills.
3-8
-------
3.3.2 Impact of Fire Codes on Substitution
Although one-for-one equipment replacement is physically feasible,
local fire codes are likely to require extensive remodeling of the building
if petroleum solvents are substituted for perc, and in some cases will not
allow conversion from perc to petroleum solvents.
Local fire codes for dry cleaning plants are usually based on model
fire codes developed by the National Fire Protection Association (NFPA).
The NFPA classified dry cleaning plants by the type of solvent used.
Solvents, in turn, are classified by their flash points. Class II and IIIA
solvents are the primary solvents used in the petroleum cleaning industry,
while perc is classified as Class IV. The NFPA Standard Number 32-1979
dry cleaning solvent classification is as follows:
• Class I Solvents - Liquids having a flash point below 38°C (100°F)
such as 32°C (90°F) flash point naphtha.
• Class II Solvents - Liquids having a flash point from 38°C to 59°C
(100°F to 139°F) such as quick drying solvents and Stoddard solvents.
• Class IIIA Solvents - Liquids having a flash point ranging from 60°C
to 93°C (140°F to 199°F) such as 60°C (140°F) "safety" solvent.
• Class IV Solvents - Liquids classified as non-flammable, such as
perc and CFC-113.
Table 3-3 presents a summary of NFPA requirements for the three types of
dry cleaning plants. As seen in this table, local building and fire codes
require different construction for buildings housing perc dry cleaning
operations than for buildings housing petroleum solvent dry cleaning
operations. These codes affect existing and new dry cleaning operations.
Local fire codes based on the NFPA Standard would require major changes to
an existing building if conversion from perc to petroleum solvents is
attempted. These changes include: construction of firewalls and fire
ceiling; extensive re-wiring of the building's electrical system; additional
plumbing for an emergency solvent drainage system; installation of a sprinkler
system; installation of storage tanks underground; and installation of a
new building heating system. The fire and building codes for a new dry
cleaning plant could be met by designing the required features into the
plant before it is built.
3-9
-------
TABLE 3-3. SUMMARY OF MAJOR NFPA MODEL FIRE CODE RECOMMENDATIONS FOR THREE TYPES
OF DRY CLEANING PLANTS
Type II
(Using petroleum solvent with flash point at or
above IOO°F but below 140"F)
Type IMA
(Using petroleum solvent with flash point at or
above I40"F but below ?00"F) •
Type IV
(Using nonflammable
liquid solvents)
00
I
• No other building occupancies
• Halls of non-combustible construction
• Emergency solvent drainage system
• Isolated dry cleaning room
t Building heated by steam, hot water, or oil only
t Boiler Isolated in separate room or building
• Adequate ventilation for dry cleaning room
• Special hazardous condition wiring
• Storage of solvent underground, above ground
outside, or limited storage in dry cleaning room
• Sprinkler system for entire building
• If other occupancies, must have sprinkler
system and two-hour fire partitions
separating occupancies
« Walls of non-combustible construction
• Emergency solvent drainage system
• Isolated dry cleaning room unless there
is a sprinkler system
• Building heated by steam, hot water or oil only
• Boiler isolated in separate room or building
• Adequate ventilation for dry cleaning room
• Wiring for ordinary conditions
• Storage of solvent underground, above ground
outside, or limited storage in dry cleaning room
• Sprinkler system if other occupancies
• Ventilation adequate to meet TWA's
• General purpose wiring
-------
Because of local fire codes, the conversion of an existing perc dry
cleaning plant to petroleum solvent may not be feasible for several
reasons. First, the dry cleaning plant may be located in a leased space,
in which case permission to make extensive changes to the space would have
to be obtained from the building owner. Dry cleaners often lease space in
shopping centers, and fire codes prevent the use of Class II solvent if
there is an adjoining occupancy. Second, limitations on floor space or the
building design could preclude the construction necessary to meet the fire
codes. Third, fire codes may restrict the use of petroleum solvent in
certain areas of a city or even in an entire city. For example, the cities
of Denver, Colorado and Phoenix, Arizona do not allow new petroleum solvent
dry cleaners to operate within city limits, while New York City does not
allow substitution of flammable for non-flammable solvents in dry cleaning
i * 17,18,19
plants.
3.3.3 Degree of Substitution
The degree to which petroleum solvents can replace perc in dry
cleaning depends in part upon the quality of cleaning done by petroleum
solvents as compared to perc. The quality of cleaning done by petroleum
solvents is determined by their effect on greases and oils, their ability
to clean articles without damaging them, and their effect on customer
service, such as cleaning time.
Both perc and petroleum solvents clean apparel primarily by dissolving
grease and oil which hold soil in the material. Once the grease or oil is
dissolved, the soil is removed mechanically by the agitation of the
solvent. Perc dissolves oils and greases more quickly than petroleum
solvent, but generally both solvents are able to clean the most heavily
soiled articles to a comparable degree of cleanliness. Perch!oroethylene
is a more aggressive solvent than petroleum solvent. Consequently, petroleum
solvents are preferred for certain applications such as leather cleaning
20
because petroleum solvent will cause less damage to garments than perc.
3-11
-------
The time required to dry clean an article and return it to a customer
depends on daily throughput, machine capacity, and machine cycle time.
Although most perc machines in use are of the transfer type, the trend in
the industry is to manufacture dry-to-dry perc machines because the latter
use solvent at a lower rate than transfer machines. A perc dry-to-dry
machine and a petroleum transfer machine of the same capacity can clean
apparel at about the same rate. Although a perc cleaning cycle lasts about
half the time of a petroleum wash cycle, the dry-to-dry machine is also
used to dry the load while articles washed in a petroleum washer are trans-
ferred to a dryer. The petroleum washer and dryer can operate continuously
and simultaneously while the perc dry-to-dry machine must alternately wash
and dry. Therefore, no loss in customer service due to longer cleaning
time is associated with the use of petroleum solvents.
3.3.4 Resource Availability
The feasibility of substituting petroleum solvents for perc in dry
cleaning depends in part upon the availability of petroleum dry cleaning
equipment, such as washers, recovery dryers, solvent stills, and storage
tanks, and the availability of petroleum solvents. Major manufacturers of
petroleum solvents, petroleum solvent washers, perc washers, petroleum
dryers, and petroleum solvent stills were contacted to determine the
availability of petroleum solvents and petroleum solvent dry cleaning
equipment.
The dry cleaning industry is not a large market for producers of
petroleum solvents. The dry cleaning industry uses about 151,000 megagrams
21
(167,000 tons) of petroleum solvent per year. This represents a
relatively small portion of the market for petroleum solvents and a very
small portion of the total petroleum liquids market (including gasoline,
heating oils, naphthas, and diesel fuel). If the demand for petroleum
solvents in the dry cleaning industry increased to three or four times the
present level of use, the increased demand would still represent a small
overall increase in demand for petroleum solvents. The petroleum refining
industry could easily supply petroleum dry cleaning solvents in amounts up
22 23
to ten times the present demand. '
3-12
-------
The total number of perch!oroethylene commercial dry cleaning plants
operating is estimated to be 18,250. The total number of perchloroethylene
industrial dry cleaning plants operating is estimated to be 750. Substitution
of petroleum solvent in these plants involves replacement of perc washing
machines, dryers, stills, and storage tanks. All domestic manufacturers of
petroleum solvent washers were contacted to determine their capacity to
manufacture petroleum washers. Companies that manufacture petroleum
washers rely upon the sale of other types of equipment for the majority of
their business because the demand for petroleum washers is very low.
Petroleum washers are built only when a company receives an order for one.
One company which manufactures industrial washers (250 pound and 500 pound
sizes) reported that an order for a petroleum washer had not been received
for two years. This company estimated that it could produce up to
100 washers of each size per year if the demand existed. Manufacturers of
commercial petroleum washers gave estimates of maximum annual production
or or 97
capacity of 180, 400, and 1000 washers, respectively. '' The limited
availability of petroleum solvent washers places a constraint upon the rate
at which perc dry cleaners could convert to petroleum solvents.
The petroleum sector of the industry is expected to use solvent recovery
dryers in the future. The popularity of recovery dryers is expected to
grow because a large percentage of petroleum solvent, which is becoming
increasingly expensive, can be recovered in the dryer and reused. At
present, only one company in the United States manufactures petroleum
recovery dryers. The company representative estimated that they have
manufactured and sold about 200 dryers of both 50 and 100 pound sizes. A
representative of the company stated that production of the dryers could
28
increase to meet a large increase in demand. The availability of recovery
dryers does not appear to be a constraint on the rate at which petroleum
solvents can be substituted for perc.
Only one company in the U.S. is known to manufacture petroleum stills.
Two sizes are manufactured: a 300 gallon per hour still and a 750 gallon
per hour still. Approximately 20 of each of these sizes can be produced
24
per year. The limited availability of petroleum solvent stills places a
3-13
-------
constraint on the rate at which petroleum solvents can be substituted for
perc. Table 3-4 presents a summary of petroleum solvent equipment manu-
facturers and their annual production capacity.
3.4 ECONOMIC ANALYSIS OF SUBSTITUTES
This section analyzes the economic feasiblity of substituting
petroleum solvents for perchloroethylene by examining the costs related to
any change in product quality and comparing capital and annualized costs
using perc and petroleum solvents. An analysis of the ability of dry
cleaners to pay for the costs of substitution is beyond the scope of this
report.
A model plant approach was chosen to represent the range of plant or
facility sizes currently used for sub-groups of the dry cleaning industry.
Each model plant is constructed using technical parameters representative
of industry production patterns.
3.4.1 Product Quality
Dry cleaning operations are, in general, local businesses which are
pn
fragmented with many small-scale, independent operations. Over half of
commercial dry cleaning establishments have fewer than five employees.30
Thus, economic competition is based not only on price, but also on certain
non-price factors such as convenience and dependable product quality.
Three areas where product quality might be expected to decline in substituting
petroleum solvents for perchloroethylene are: cleanliness of the article;
timeliness with which it is returned to the customer; and absence of
damage resulting from the cleaning process. There are no fixed standards
for measuring quality in these areas. Consumer behavior, however, is a
good proxy for judging overall performance. If the quality of dry cleaning
service significantly declines, consumers will likely change their behavior
patterns. Consumer response could vary from deferred maintenance of
dry-cleanable articles to more frequent purchases of easy-care clothing and
fabrics. The result of these or similar actions would impose economic
costs on dry cleaners. At a minimum, dry cleaners would suffer the cost of
poor reputation. At a maximum, there would be the financial costs of lost
revenue which could result in lost profits.
3-14
-------
TABLE 3-4. ESTIMATED U.S. PRODUCTION CAPACITY FOR PETROLEUM SOLVENT
DRY CLEANING EQUIPMENT
Type of
equipment and
manufacturer
Estimated
production capacity
(units/year)
Washers
Four State Machinery
Joplin, MO
Marvel Manufacturing Co.
San Antonio, TX
VIC Manufacturing
Minneapolis, MN
Washex Manufacturing Co.
Wichita Falls, TX
,000a
180b
400C
200d
Recovery Dryers
Hoyt Manufacturing Corp.
Westport, MA
>2,400{
Solvent Stills
Washex Manufacturing Co.
Wichita Falls, TX
40C
Reference 27.
Reference 25.
cReference 26.
Reference 24.
eAlthough estimate appears high, Hoyt stated that they could produce more
than 200 units per month. Reference 28.
3-15
-------
While it is beyond the scope of this analysis to place a doller value
on reputation loss or to estimate the dollar value of lost revenues and
profits, it is possible to evaluate the probability for increased costs.
This probability is assumed to be inversely proportional to the degree of
substitutability.
3.4.1.1 Cleanliness
The Technical Analysis component of this section concludes that
petroleum solvent is highly comparable to perc in cleaning ability.
Therefore, it is highly probable that commercial and industrial dry cleaners
will not suffer in this aspect of product quality. Consequently, no added
costs due to substitution are forecast.
3.4.1.2 Timeliness
As mentioned previously, the use of petroleum solvent does not prolong
the time of returning dry cleaned articles to customers. With no decline
in this area of product quality due to substitution, no added costs are
foreseen.
3.4.1.3 Damage
Because petroleum solvents are less aggressive than perc, they are
less likely to damage articles than perc. Since there is no loss of
product quality from this perspective, it is assumed that substitution will
impose no added costs.
Technically, petroleum solvents are complete substitutes for
perchloroethylene in dry cleaning. Therefore, substitution of petroleum
solvents for perc should impose neither additional costs to dry cleaners in
loss of customer good will nor in lost revenues and lost profits.
3.4.2 Capital and Annualized Costs of Substitution
Capital costs include the expense of any new equipment and the labor,
materials, and miscellaneous expenses of installing and making it operational.
Capital costs are particularly relevant in assessing the economic feasibility
of converting an existing perc dry cleaning facility to one which uses
petroleum solvents. As pointed out previously in this section, perc equipment
3-16
-------
cannot use petroleum solvent without major equipment modification.
Therefore new equipment, specifically manufactured for petroleum solvent
use, must be purchased.
Annualized operating costs are estimated for both perc and petroleum
dry cleaning facilities. As previously stated, these cost comparisons are
based on model plants, which represent a range of dry cleaning facilities
in terms of capacity and nature of service (i.e. commercial or industrial).
Annualized cost comparisons are relevant in assessing the economic feasibility
of both existing plant conversions and new plant construction. Comparing
key line item operating costs shows the incremental cost of conversion.
This is the additional cost burden attributable to substitution which will
recur annually.
3.4.2.1 Model Plant Parameters
The annualized operating costs of perc and petroleum plants are
compared in three model plants. Each plant represents a range of plant
characteristics typical within the industry. The parameters for the model
plants are summarized in Tables 3-5 and 3-6. The plants compared are a
small commercial plant, a large commercial plant, and an industrial plant.
Both the perc and petroleum plants are equipped with solvent recovery
equipment. For the perc equipment, a carbon adsorption system is used for
recovery. As previously mentioned, the petroleum plant is equipped with a
recovery dryer. The perc plant is assumed to use a dry-to-dry machine.
3.4.2.2 Capital Costs
Capital costs for three petroleum model plant facilities are presented
in Tables 3-7, 3-8, and 3-9. The new pieces of equipment that need to be
purchased as a result of converting from perc to petroleum solvents are a
washer, a recovery dryer, a water chiller for the dryer, a vacuum still,
and a solvent storage tank. Equipment costs were obtained from manufacturers
and equipment vendors. Taxes, freight and instrumentation are treated as a
single component and calculated at 18 percent of equipment costs.31
Installation costs are estimated on the basis that all control equipment
and process equipment are installed by an outside contractor at 10 percent
3-17
-------
TABLE 3-5. PERCHLOROETHYLENE MODEL PLANT PARAMETERS
33
to
I
00
Parameter
Annual plant throughput,
kg (Ibs)
Days of operation per year
Throughput description
Number of washers
Washer capacity, kg (Ibs)
Average washer load weight,
kg (Ibs)
Number of washer loads per day
Wash cycle time, minutes
Small
commercial
14,625
(32,243)
250
General apparel
1
11
(25)
9
(20)
6.5
57a
Model plants
Large
commercial
29,250
(64,485)
250
General apparel
1
23
(50)
18
(40)
6.5
57a
Industrial
280,800
(619,058)
260
Industrial articles
1
114
(250)
90
(198)
12
35b
For dry-to-dry machines.
For transfer machines.
-------
TABLE 3-6. PETROLEUM MODEL PLANT PARAMETERS
34
co
i
Parameter
Annual plant throughput,
kg (Ibs)
Days of operation per year
Throughput description
Number of washers
Washer capacity, kg (Ibs)
Average washer load weight,
kg (Ibs)
Number of washer loads per day
Wash cycle time, minutes
Number of recovery dryers
Dryer capacity, kg (Ibs)
Dryer cycle time, minutes
Number of vacuum stills
Vacuum still capacity,
1/hr (gal/hr)
Small
commercial
15,000
(33,069)
250
General apparel
1
16
(35)
10
(22)
6
20
1
23
(50)
25
1
95
(25)
Model plants
Large
commercial
32,000
(70,548)
250
General apparel
1
23
(50)
16
(35)
8
25
1
45
(100)
30
1
189
(50)
Industrial
260,000
(573,202)
260
Industrial articles
1
114
(250)
100
(220)
10
40
3
45
(100)
40
1
1,894
(500)
-------
TABLE 3-7. CAPITAL COSTS FOR CONVERTING A SMALL COMMERCIAL MODEL
PLANT TO PETROLEUM SOLVENT31,32,35
Description
Equipment
16 kg washer/extractor
23 kg recovery dryer
Water chiller for dryer
100 1/hr vacuum still
760 liter solvent storage tank
Taxes, freight, instrumentation
Equipment installation0
Quantity
1
1
1
1
1
Subtotal
Total
Cost3
7,500
15,640
2,320
2,100
600
28,160
5,070
2,816
36,046
First quarter 1981 dollars.
Equals 18 percent of equipment costs
cEquals 10 percent of equipment costs
3-20
-------
TABLE 3-8. CAPITAL COSTS FOR CONVERTING A LARGE COMMERCIAL MODEL
PLANT TO PETROLEUM SOLVENT31,32,36
Description
Equipment
23 kg washer/extractor
23 kg recovery dryer
Water chiller for dryer
190 1/hr vacuum still
760 liter solvent storage tank
Taxes, freight, instrumentation
Equipment installation0
Quantity
1
1
1
1
1
Subtotal
Total
Cost3
13,400
15,640
2,320
4,200
600
36,160
6,510
3,616
46,286
First quarter 1981 dollars.
Equals 18 percent of equipment costs.
cEquals 10 percent of equipment costs.
3-21
-------
TABLE 3-9. CAPITAL COSTS FOR CONVERTING AN INDUSTRIAL MODEL
PLANT TO PETROLEUM SOLVENT31,32,37
Description
Equipment
115 kg washer/extractor
45 kg recovery dryer
Water chiller for dryer
1900 1/hr vacuum still
15,150 liter solvent storage tank
Taxes, freight, instrumentation
Equipment installation0
Quantity
1
3
3
1
1
Subtotal
Total
Cost3
55,000
48,540
7,880
51,390
1,500
164,310
29,576
16,431
210,317
First quarter 1981 dollars.
Equals 18 percent of equipment costs,
""Equals 10 percent of equipment costs,
3-22
-------
32
of the equipment cost. It is important to note that the petroleum
equipment costs include a recovery dryer. As previously mentioned,
recovery dryers are the type of dryer expected to be used by the petroleum
sector of the industry in the future. The recovery dryer and the required
water chiller equipment constitute a significant percentage of the total
cost. For example, in a small commercial plant, these items represent
64 percent of the equipment cost; 50 percent in a large commercial plant;
and 34 percent in an industrial plant. As will be seen later in this
section, the recovery dryer's expense as a capital item contributes to a
substantial savings in annualized operating costs.
3.4.2.3 Annualized Operating Costs
The relevant operating costs which are estimated include: solvent;
steam; electricity; operating labor; maintenance; overhead expenses of
administration, taxes, and insurance; and capital recovery. Annualized
costs of converting from perc to petroleum solvents range from approximately
$1,200 for a small commercial plant to $9,200 for an industrial plant. In
estimating comparative solvent costs, the amount of solvent consumed each
year is assumed to be equal to the amount of solvent lost during the
drying cycle, which is equal to the amount of solvent emitted from the
dryer minus the amount of solvent recovered by solvent recovery devices.
Perchloroethylene consumption has been conservatively estimated to be about
5.0 kg per 100 kg of clothes cleaned (or about 0.36 gallons per 100 Ibs).38
Uncontrolled petroleum solvent losses from drying have been conservatively
estimated to be 18.9 kg per 100 kg of clothes cleaned (or about 2.9 gallons
39
per 100 Ibs). Tests conducted on recovery dryers show that between
65 and 95 percent of the petroleum solvent normally vented to the atmosphere
40
can be recovered. For the purpose of this study an average solvent
recovery rate of 80 percent is assumed. Reducing petroleum solvent losses
80 percent with a recovery dryer results in a total dryer solvent loss rate
of 3.8 kg per 100 kg of clothes cleaned (0.6 gallon per 100 Ibs). Total
solvent emissions with a recovery dryer are roughly 8.0 kg per 100 kg of
38
clothes cleaned (1.25 gallons per 100 Ibs). Perc is valued at $0.57 per
kg ($3.50 per gallon). The solvent cost of dry cleaning with perc i
s
computed to be $2.80 per 100 kg of clothes cleaned. Petroleum solvents are
,n).4C
3-23
valued at $0.56 per kg ($1.65 per gallon). The solvent cost of dry
-------
cleaning with petroleum solvents is computed to be $4.48 per 100 kg of
clothes cleaned. Thus, perc has a slight cost advantage over petroleum
solvents under the given assumptions. Tables 3-10, 3-11, and 3-12 summarize
comparative annual solvent costs for each model plant.
For an average dry-to-dry machine, the steam requirement for drying is
2.9 boiler horsepower (BMP) per 100 Ibs. of clothes cleaned. A recovery
dryer requires 2.5 BMP per 100 Ibs. of clothes cleaned. Therefore, a
perc machine requires about 0.4 BMP more than a petroleum recovery dryer
per 100 Ibs. of clothes cleaned. Steam costs about $0.12 per BHP. The
difference in the cost of steam between perc and petroleum solvent is
$0.05 per 100 Ibs. of clothes cleaned. Tables 3-10 thru 3-12 show perc and
petroleum plants to have comparable annualized steam costs.
Comparative annual costs of electricity show a general parity between
petroleum and perc plants. Electricity costs, calculated from manufacturer's
literature and based on $0.06 per kWh, show that a small commercial perc
washer costs $24 less to operate annually than a small commercial petroleum
washer and dryer combination, while an industrial perc washer costs $310
more to operate annually than an industrial petroleum washer and dryer
44 45
combination. '
Labor requirements for operating dry cleaning machinery in perc and
petroleum plants is assumed to be the same for each type plant. Labor
costs range from $4,300 per year for a small commercial plant to $11,160 per
year for an industrial plant.
Maintenance costs associated with dry cleaning are also assumed to be
the same for perc and petroleum plants. Annual maintenance cost range from
$830 for a small commercial plant to $3,590 for an industrial plant.46
Overhead, consisting of taxes, insurance and administrative costs, is
estimated to be four percent of the equipment costs.40 Overhead costs
range from between $1,442 for a small commercial plant to $8,413 for an
industrial plant, and are assumed to be the same for perc and petroleum
plants.
3-24
-------
TABLE 3-10. COMPARATIVE ANNUALIZED OPERATING COSTS OF USING PETROLEUM
SOLVENT AND PERC IN A SMALL MODEL PLANT
Operating costs
Solvent
Steam
Electricity
Labor
Maintenance
Adm. , ins. , and taxes
Capital recovery
SUBTOTAL
Perc plant
costs, $
(A)
417
112
103
4,300
830
1,442
3,023b
10,227
Petroleum
plant costs, $
(B)
672
99
127
4,300
830
1,442
3,990C
11,460
Increase
in cost, $
(B - A)
255
(13)a
24
0
0
0
967
1,233
aNet credit.
Capital recovery is based on an existing perc machine with a purchase price
of $23,000; the estimated useful life is 15 years and the interest rate
is 10 percent. Reference 39.
cCapital recovery is based on a new petroleum washer, dryer, still, and
storage tank with a total installed cost of $36,000, an estimated useful
life of 30 years, and an interest rate of 10 percent. Reference 40.
3-25
-------
TABLE 3-11. COMPARATIVE ANNUALIZED OPERATING COSTS OF USING PETROLEUM SOLVENT
AND PERC IN A LARGE COMMERCIAL MODEL PLANT
Operating costs
Solvent
Steam
Electricity
Labor
Maintenance
Adm. , ins. , and taxes
Capital recovery
SUBTOTAL
Perc plant
costs, $
(A)
834
225
117
5,720
830
1,851
3,825b
13,402
Petroleum
plant costs, $
(B)
1,434
212
264
5,720
830
1,851
5,124C
15,432
Increase
in costs, $
(B - A)
600
(13)a
147
0
0
0
1,299.
2,033
aNet credit.
Capital recovery is based on an existing perc machine with a purchase price
of $29,000; the estimated useful life is 15 years and the interest rate
is 10 percent. Reference 39.
cCapital recovery is based on a new petroleum washer, dryer, still, and
storage tank with a total installed cost of $46,300, an estimated useful
life of 30 years, and an interest rate of 10 percent. Reference 40.
3-26
-------
TABLE 3-12. COMPARATIVE ANNUALIZED OPERATING COSTS OF USIKG PETROLEUM
SOLVENT AND PERC IN AN INDUSTRIAL MODEL PLANT
Operating costs
Solvent
Steam
Electricity
Labor
Maintenance
Adm. , ins. , and taxes
Capital recovery
SUBTOTAL
Perc plant
costs, $
(A)
8,003
2,154
1,670
11,160
2,590
8,413
17,091b
51,081
Petroleum
plant costs, $
(B)
11,648
1,857
1,360
11,160
2,590
8,413
23,282C
60,310
Increase
in costs, $
(B - A)
3,645
(297)a
(310)
0
0
0
6,191
9,229
aNet credit.
Capital recovery is based on an existing perc machine with a purchase price
of $130,000; the estimated useful life is 15 years and the interest rate
is 10 percent. Reference 3B.
cCapital recovery is based on a new petroleum washer, dryer, still, and
storage tank with a total installed cost of $210,300, an estimated useful
life of 30 years, and an interest rate of 10 percent. Reference 40.
3-27
-------
The capital recovery cost for the perc plant is based on a 10 percent
41
interest rate and an expected equipment life of 15 years. For the
petroleum plant, capital recovery is based on a 10 percent interest rate
and a 30 year equipment life. The Halogenated Cleaning Solvents Association
(HCSA) has suggested that although a 30 year life expectancy for a petroleum
washer may be possible, a 15-year life expectancy may be more realistic
in view of technological changes and increasing equipment maintenance
costs as the washer ages (see HCSA comments in Appendix B).
3.4.2.4 Costs of Fire and Building Code Compliance
In addition to capital and operating costs, there is another factor
unique to the analysis of substituting petroleum solvent for perc. This
is the cost of additional materials and labor required to bring an existing
or new facility into compliance with local fire and building codes. The
Technical Analysis section discussed the additional safety requirements
imposed on petroleum solvent dry cleaning facilities. From an economic
perspective, these requirements are important in determining the feasibility
of substitution. There are two reasons for this. First, the magnitude
of the added costs to build or convert to a petroleum solvent facility
can be great. For example, the Southern Building Code Congress estimates
an average 30 percent increase in construction costs (per square foot) to
build a Type 2 versus a Type 5 building. Type 2 is a category of building
construction required for petroleum dry cleaners because of to the low
flashpoint of petroleum solvents. A Type 5 building has "normal" construction
47
characteristics. Costs of conversion could include rewiring, fire
walls, and boiler modifications to provide an explosion-resistant
facility. The second reason that fire and building code requirements are
crucial to this analysis is that they pose potential logistical as well
as economic constraints in the case of converting an existing plant. A
scenario in which an existing perc plant is required to convert to petroleum
solvent might find an establishment physically unable to make the conversion,
the added cost notwithstanding. This would leave the proprietor with the
option of finding new space relocating the dry cleaning equipment while
maintaining a storefront in the same location, or going out of business.
3-28
-------
3.5 CONCLUSIONS AND RECOMMENDATIONS
The substitution of petroleum solvents for perc is feasible on the
basis of product quality and of physical replacement of perc equipment
with petroleum equipment. Capital costs of conversion range from $36,000
for a small commercial establishment to $210,000 for a large industrial
plant. This study did not determine the ability of the user to pay these
costs. In addition to the capital costs of conversion, local fire codes
may require expensive remodeling of the building, which is not always
possible when the dry cleaner is located in a leased space or a shopping
center. Fire codes in some cities make substitution of petrolum solvents
for perc illegal, a situation that can be determined on an area-by-area
basis. While substitution of petroleum solvents for perc is technically
feasible, fire codes are the primary obstacle to converting to petroleum
solvents in the dry cleaning industry. In addition, the limited availability
of petroleum washers and dryers, and solvent stills places a constraint
on the rate at which the industry could convert from perc to petroleum
solvents.
3-29
-------
3.6 REFERENCES
1. United States Environmental Protection Agency. Perchloroethylene Dry
Cleaners - Background Information for Proposed Standards. Office of Air
Quality Planning and Standards. Research Triangle Park, NC.
EPA-450/3-79-029a. August 1980. p. 3-2 to 3-3.
2. Reference 1, pg. 3-7.
3. United States Environmental Protection Agency. Petroleum Dry Cleaners -
Background Information for Proposed Standards (Preliminary Draft).
Office of Air Quality Planning and Standards. Research Triangle Park,
N.C. November 1981. p. 4-1.
4. Reference 3, pg. 3-1.
5. Reference 1, pg. 3-4.
6. Reference 3, pg. 3-3.
7. United States Environmental Protection Agency. Control of Volatile
Organic Emissions from Perchloroethylene Dry Cleaning Systems.
EPA-450/2-78-050. Office of Air Quality Planning and Standards.
Research Triangle Park, NC. December, 1978.
8. Personal communication. Lester Y. Pilcher, GCA Corporation with
Bud Sluizer, Institute of Industrial Launderers. October 6, 1981.
9. Reference 3, pg. 3-1.
10. National Fire Protection Association. Standard for Drycleaning Plants.
NFPA 32-1979. Quincy, MA.
11. Materials balance provided to GCA Corporation by EPA Toxic Substances
Priority Committee, August 27, 1981.
12. Personal communication. Timothy Curtin, GCA Corporation with
Steve Plaisance, TRW, RTP, NC. September 24, 1981.
13. Johnson, Keith. Dry Cleaning and Degreasing Chemicals and Processes.
Park Ridge, NO. Noyes Data Corporation, 1973. pp. 3-36.
14. Personal communication. Samuel Duletsky, GCA Corporation with
William Fisher, International Fabricare Institute, Silver Spring, MD.
November 3, 1981.
3-30
-------
15. Personal communication. Samuel Duletsky, GCA Corporation with
Frank Vitek, National Automatic Laundry and Cleaning Council, Chicago,
IL. October 23, 1981.
16. Personal communication. Samuel Duletsky, GCA Corporation with Tom Briggs,
International Conference of Buildings Officials, Whittier, CA.
November 19, 1981.
17. Personal communication. Samuel Duletsky, GCA Corporation with Paul Spurgeon,
Fire Prevention, Denver, CO. November 10, 1981.
18. Personal communication. Samuel Duletsky, GCA Corporation with
Captain Hudson, Fire Prevention, Phoenix, AX. November 10, 1981.
19. Letter from Joseph C. Hess, Chief of Fire Prevention of the City of New
York, to Samuel Duletsky, GCA Corporation, December 8, 1981.
20. Reference 3, pg. 9-2.
21. Chemical Economics Handbook, SRI International, Menlo Park, CA, p. 300.3700E.
22. Personal communication. Samuel Duletsky, GCA Corporation with
Buddy Whitlock, Ashland Oil Company, Columbus, OH. November 4, 1981.
23. Personal communication. Samuel Duletsky, GCA Corporation with
Jim Watson, Getty Refining and Marketing Company, Tulsa, OK.
November 4, 1981.
24. Personal communication. Samuel Duletsky, GCA Corporation with
Jim Montgomery, Washex Machinery Corporation, Wichita Falls, TX.
November 4, 1981.
25. Personal communication. Samuel Duletsky, GCA Corporation with
Gordon Carruth, Marvel Manufacturing Co., San Antonio, TX.
November 10, 1981.
26. Personal communication. Samuel Duletsky, GCA Corporation with
Ray McMonagle, VIC Manufacturing Co., Minneapolis, MN.
November 10, 1981.
27. Personal communication. Samuel Duletsky, GCA Corporation with
Albert Jenkins, Four State Machinery Manufacturing Co., Joplin, MO.
November 13, 1981.
28. Personal communication. Samuel Duletsky, GCA Corporation with
Derek Oakes, Hoyt Manufacturing Corp., Westport MA. November 5, 1981.
29. Reference 3, p. 9-15.
30. Reference 3, p. 9-4.
31. Reference 3, p. 8-1.
3-31
-------
32. Reference 3, p. 8-3.
33. Reference 1, p. 6-2.
34. Reference 3, p. 6-3.
35. Reference 3, pp. 8-2 and 8-4.
36. Reference 3, pp. 8-2 and 8-5.
37. Reference 3, pp. 8-2 and 8-7.
38. Personal communication. Richard Rehm, GCA Corporation with Steve Shedd,
U.S. Environmental Protection Agency, Research Triangle Park, NC,
February 23, 1982.
39. VIC Manufacturing Company. Let's Compare the Costs of Perc and
Petroleum. Brochure. 1981.
40. Reference 3, p. 8-9.
41. Personal Communication. Hugh F. Rollins, GCA Corporation with
Ray McMonagle, VIC Manufacturing Co., Minneapolis, MN. November 25, 1981
42. Reference 3, p. 8-11.
43. Reference 3. p. 8-10.
44. VIC Manufacturing Company. Specifications-Models 405-406-406 FS-424.
Number 2/81.
45. Washex Machinery Corporation. Product Specification Sheet for Floataire
250-pound Washer. Number SB-289c.
46. Reference 3, pp. 8-14 to 8-17.
47. Personal communication. Hugh'F. Rollins, GCA Corporation with
John Parham, City of Durham, N.C. December 7, 1981.
3-32
-------
4.0 SURFACE COATINGS
4.1 GENERAL DESCRIPTION OF USE
Surface coatings have a wide variety of uses, such as decoration,
weather and chemical protection, and safety marking. Surface coatings
are grouped into three main categories: architectural paints, product
finishes, and special purpose coatings. Architectural paints are formulated
for application to interior and exterior surfaces of buildings. Product
finishes are formulated for factory application on a range of items
including automobiles, appliances, furniture, metal containers and
aircraft. Special purpose coatings are formulated for special applications
or environmental conditions and include industrial maintenance paints,
automotive refinishes, traffic paints and aerosol paints.
Surface coatings are typically composed of three basic components:
(1) a film-forming binder consisting of resins or drying oils, (2) a
dispersion medium of volatile solvents or water which maintains fluidity,
and (3) a pigment system containing coloring and opacifying materials
and various extenders. The binder plus the solvent is referred to as
the vehicle. When a coating is applied to a substrate, the volatile
solvent evaporates, leaving the binder and pigment to form an adherent
film.1
There are three major types of coatings: paints, lacquers, and
varnishes. All paints contain pigments. Solvent-based paints dry by a
combination of oxidation and polymerization of the binder after evaporation
of the solvent, while water-based paints form films by coalescence of
the binders and pigments as the water evaporates. Most lacquers are
pigmented materials and dry by the evaporation of their volatile components.
Varnishes are clear coatings with no pigmentation, and as with solvent-
based paints, cure through a polymeric reaction of the binder with the
2
oxygen in air after evaporation of the solvent.
4-1
-------
Chlorinated solvents, because of their expense, are not used to a
great extent in the formulation of surface coatings. However, available
information indicates that they are used to a small extent in some
painting operations. Methylene chloride is used as a solvent in some
traffic and aerosol paints while 1,1,1-trichloroethane is used as a
solvent in some traffic paint formulations. According to the National
Paint and Coating Association (NPCA), of the approximately 1.8 million
megagrams (2.0 million tons) of solvents used annually in the formulation
of coatings, only 7,700 megagrams (8,500 tons) or 0.4 percent is methylene
chloride (the only chlorinated solvent for which the NPCA has consumption
data).3 Other sources estimate that about 7.5 percent of all solvents
used annually in traffic paints is 1,1,1-trichloroethane.
Because 1,1,1-trichloroethane and methylene chloride are not photochemically
reactive, they are being marketed aggressively as substitutes for various
aliphatic and aromatic solvents presently used in surface coating operations.
Thus, the amount of 1,1,1-trichloroethane and methylene chloride used in
traffic paints and aerosol paints may actually increase. Use of
1,1,1-trichloroethane and methylene chloride may expand to other surface
coating operations including architectural coatings and product finishes.
This report does not examine the potential impact of this expansion.
Rather, it examines the practicality of replacing chlorinated solvents
with conventional solvents.
4.2 TECHNICAL ANALYSIS OF SUBSTITUTES
This section assesses and discusses the available substitutes for
methylene chloride in aerosol paints, and methylene chloride and
1,1,1-trichloroethane in traffic paints, the effect of substitution of
these solvents on product quality, and the resource availability of the
substitute solvents.
4.2.1 Aerosol Paints
Aerosol paints contain a propellant in addition to the three major
coating components (binder, pigment system and solvent). The propellants
used in aerosols are typically low molecular weight hydrocarbons such as
4-2
-------
propane, isopropane, butane, and isobutane. A wide variety of resin
and pigment systems are used. Aromatic hydrocarbons, such as toluene
and xylene, and oxygenated solvents, such as acetone and methyl ethyl
ketone, generally are used as primary solvents. Methylene chloride is
used frequently as a cosolvent, usually comprising five to ten percent
of the formulation,6 and in some cases as high as 30 percent. It is
estimated that approximately 5,700 megagrams3 (6,300 tons) to 6,600 megagrams
(7,300 tons) of methylene chloride are used annually in the formulation
of aerosol coatings. Methylene chloride is used because of its good
solubility properties, rapid rate of evaporation, high specific gravity,
and because it aids atomization, acts as a vapor pressure depressant for
high pressure propellents, and reduces flammability. ' '
4.2.1.1 Substitutes
Potential solvent substitutes for methylene chloride in aerosol
paint formulations are listed with selected physical properties in
Table 4-1. Substitution for methylene chloride may involve an increase
in the amount of the existing primary solvent or solvent blend, or the
addition of a different solvent. Substitution of solvents may involve
more than a "one-for-one" substitution, because aerosol paint formulations
are complex mixtures of substances. The substitute solvent must have
similar solubility properties in relation to the resin systems and
propellent when used in conjunction with other solvents in the formulation.
A change in solvent may change the properties of the complete aerosol
11
system and must be studied for each formulation.
Calculated from mass balance estimates of the total use of methylene
chloride in aerosol formulation (40,500 Mg/yr)1* and the percentage of
aerosol units containing coatings and finishes (14 percent).8'9
Estimated from NPCA data assuming that all usage of methylene chloride
listed as "miscellaneous" is in aerosol paints. Usage of methylene
chloride in aerosol paints is not listed separately and the primary use
of methylene chloride other than the separately listed categories is in
aerosol paints.
4-3
-------
The selection of a solvent substitute is dependent on "its ability to
maintain the homogeneity of the aerosol system. This ability is a function
of the substitute's solubility characteristics. Table 4-1 lists the
solubility parameters of potential substitute solvents. Solubility
parameters may be used as an indication of the relative solvency power of
chemicals. In general, as the solubility parameter increases, the solvent
becomes more powerful. The solubility parameter of methylene chloride is
9.7. Of the solvents listed, the alcohols exhibit solubility parameters
ranging from 11.4 to 14.5, esters in the range of 9.1 to 9.5, ketones from
8.3 to 10.0, aromatics at 8.9 and the aliphatics in the range of 7.3 to
7.4.
The solubility characteristics of solvents must be assessed in the
context of the specific formulation. The major resin systems that are used
in coating formulations and compatible solvents are as follows:
Al_ky_d_--Alkyd resins are the condensation products of saturated polycarboxylic
acids and polyfunctional alcohols modified by fatty acids. Phthalic
anhydride is used in about 85 percent of all alkyds produced. The type of
solvent used in alkyd coatings is dependent on the molecular weight of the
resin and the amount of oils present. Short oil-length and medium
oil-length alkyd resins are compatable with aromatics, esters and alcohols.
Acrylic—Acrylic resins are predominantly polymers and copolymers of
esters of acrylic and methacrylic acid and require relatively strong
solvents such as toluene, xylene, acetone or methyl ethyl ketone.
Epoxy—Epoxy resins are polymers containing a three-membered epoxide
ring containing two carbon atoms and one oxygen atom. The cosolvents used
for most unmodified epoxy resins are ketones, esters, and glycol ethers.
Ure_tha_ne_s_--lire thane resins are polymers formed by the reaction of
isocyanates and alcohols. Nonreactive urethane resins are dissolved in
aliphatic or aromatic hydrocarbon solvents. Urethane lacquers and reactive
urethane resin systems require oxygenated solvents (typically ethyl acetate
and butyl acetate) as primary solvents and aromatic solvents as diluents.
cThe solubility parameter is the square root of the cohesive energy density
which is the summation of interaction energies between molecules.12
4-4
-------
TABLE 4-1. POTENTIAL SOLVENT SUBSTITUTES FOR METHYLENE CHLORIDE IN AEROSOL PAINTS
13
en
Solvent
Alcohols
Methanol
Ethanol
Isopropanol •
Ketones and esters
Acetone
Methyl ethyl ketone
Methyl acetate
Ethyl acetate
Aliphatic hydrocarbons
Hexanes
Heptanes
Aromatic hydrocarbons
Toluene
Xylene
Methyl ene chloride3
Specific
gravity
((a 20/20°C)
0.793
0.792
0.787
0.792
0.806
0.904
0.902
0.675
0.69
0.872
0.871
1.32
Solubility
parameter
12.8
14.5
11.4
10.0
9.3
9.5
9.1
7.3
7.4
8.9
8.9
9.7
Distillation
range
64-65
74-80
82-83
55.5-56.5
79-80
53-59
76-79.5
66-70.5
93.6-98.4
110-111
130-140
40.0-40.8
Evaporation
rate
(n-Butyl
acetate = 1)
3.5
1.9
1.7
7.7
4.6
11.8
4.1
8.1
4.5
1.5
0.75
14.5
Vapor
pressure
(mm Hg
9 20°C)
96
44
31
185
70.6
26.3
76
140
45
38
352
'included for comparison purposes only.
-------
Cellulosics--The major cellulosic resin used is nitrocellulose.
Cellulose acetate, cellulose butyrate, and ethyl cellulose are used to a
much lesser extent. Solvents used in cellulosic coatings are typically
lower molecular weight ketones, esters, and glycol ethers.
Vinyl--Most of the vinyl resin systems used in coatings are polymers
and copolymers of vinyl acetate and vinyl chloride and can be dissolved in
1 14
ketones and esters. '
The hydrocarbon propellants generally used in aerosol paint formulations
typically have poor solubility characteristics. In some cases a change
in the solvent system could require a change in propellant. Dimethyl ether
has been identified as a possible substitute propellant for aerosol systems
in which methylene chloride is used as a co-solvent. Because of its better
solubility properties relative to the hydrocarbons, it could possibly be
used as a propellant when change in a solvent system containing methylene
chloride result in a loss of homogeneity in the system.
Choice of the solvent substitute is also dependent on the ability of
the solvent to maintain the application properties of the coating. The
rate of evaporation of a solvent or solvent blend from a coating is important
in spray application. If a solvent evaporation rate is too fast, too much
solvent leaves the coating prior to contact with substrate resulting in
stringing or cobwebbing of the spray or rough surfaces and "orange-peeling"
of the paint film on the substrate. If the solvent evaporation rate is too
slow, the coating will tend to sag or run. The evaporation rate of a
solvent from a coating depends on a number of factors including: temperature
of the fluid, temperature of the air above the fluid, air movement, surface
tension, humidity, solvent vapor pressure, and solvent-resin interactions.18
Table 4-1 lists vapor pressures and evaporation rates of solvents which are
parameters that are indicative of the rate at which solvents are released
from aerosol paints during drying. Evaporation rates of solvents are not
absolute values and thus are shown relative to the rate of evaporation of
n-butyl acetate. None of the potential substitute solvents have evaporation
rates as fast or vapor pressures as high as methylene chloride, which has
an evaporation rate relative to n-butyl acetate of 14.5 and a vapor pressure
4-6
-------
of 340 mm Hg at 20°C. The high vapor pressure of methylene chloride assists
in atomization of the paint. In addition, none of the potential substitute
solvents have specific gravities as high as methylene chloride. Because of
this, aerosol paints formulated with less dense solvents may not be able to
meet government procurement specifications that require aerosol paints to
contain 13 ounces by weight per 16 ounce volume can.
Substitution of solvents for methylene chloride in aerosol paints is
considered to be technically feasible for the majority of formulations.
One company estimated that approximately 10 percent of aerosol paint formulations
would not tolerate substitution of methylene chloride by another solvent.
4.2.1.2 Effect of Solvent Substitution on Product Quality
Because substitutes are generally slower evaporating than methylene
chloride, coatings formulated with substitute solvents may have more of a
tendency to run or sag; however, these effects should not be significant.
A few companies that have been substituting other solvents for methylene
chloride where possible because of its expense have stated that the product
quality has been maintained in these paints. ' '
4.2.1.3 Resource Availability
Since the annual use of methylene chloride in the formulation of
aerosols is estimated to be only about 5,700 megagrams (6,300 tons) to
6,600 megagrams (7,300 tons), it is anticipated that there will be an
adequate supply of solvent substitutes.
4.2.2 Traffic Paints
Traffic paints are applied to streets, highways, airport runways and
other pavement areas where markings are needed. Traffic paints are sold by
competitive bid to Federal, State, and local governments and independent
marking companies. The majority of the paints are based on alkyd resin
systems. Chlorinated rubber resins are used to a lesser extent.
According to the NPCA, of the 67,000 megagrams (74,000 tons) of solvents
used annually in the formulation of traffic paints, only 1.6 percent or
1,100 mecagrams (1,200 tons) are methylene chloride. 1,1,1-Trichloroethane
4-7
-------
is also used in the formulation of traffic paints, with an estimated annual
consumption of 5,000 megagrams (5,500 tons). Manufacturers of traffic
paint application equipment are issuing warnings that halogenated solvents
in paint formulations cause corrosion of equipment which may result in a
20
decrease of the use of chlorinated solvents in traffic paint formulation.
4.2.2.1 Substitutes
Potential substitute solvents for 1,1,1-trichloroethane and methylene
chloride in traffic paints are the same as those listed for aerosol formulations
in Table 4-1. The most frequently mentioned are acetone, methyl ethyl
20 21 22
ketone, toluene and hexane. These four solvents and selected
physical properties are listed in Table 4-2 for comparison with methylene
chloride and 1,1,1-trichloroethane. As in aerosol formulations, the selection
of the solvent substitute is dependent on the ability of the solvent to
maintain the homogeneity of the formulation and its application properties.
In addition, traffic paints must meet performance specifications of the
Federal, State or local government for which the paint is formulated.
Substitute solvents must have solubility characteristics similar to
methylene chloride and 1,1,1-trichloroethane. With the exception of hexanes,
the substitute solvents have larger solubility parameters than
1,1,1-trichloroethane, while only acetone has a solubility parameter larger
than methylene chloride (see Table 4-2). Solubility parameters give only a
general indication of relative solvency power. The solubility characteristics
of the solvent must be assessed in the context of the specific formulation.
Chlorinated solvents are typically used in paints based on chlorinated
rubber resins. Methyl ethyl ketone and toluene are solvents that are
21
widely used for this type of resin system. Acetone is also compatible
20
with chlorinated rubber resins.
4.2.2.2 Effect of Substitutes on Product Quality
Traffic paints are evaluated for performance characteristics such as
film thickness of the applied paint, durability, bead retention (retention
of glass beads added to increase the reflectance of the markings), and dry
23
or "no track" time. It is not anticipated that substitution would adversely
4-8
-------
TABLE 4-2. POTENTIAL SOLVENT SUBSTITUTES IN TRAFFIC PAINT
13
Solvent
Acetone
Methyl ethyl ketone
Hexanes
Toluene
Methyl ene chloride3
l,l,l-Trichloroethanea
Specific
gravity
(@ 20/20°C)
0.792
0.806
0.675
0.872
1.32
1.32
Solubility
parameter
10.0
9.3
7.3
8.9
9.7
8.5
Distil
lation
range
55.5
79
66
110
40.0
- 56.5
- 80
- 70.5
- Ill
- 40.8
74
Evaporation
rate
(n-Butyl
acetate = 1)
7.7
4.6
8.1
1.5
14.5
6.0
Vapor
pressure
(mm Hg
@ 20°C)
185
70.6
•140
38
352.1
104.5
I
10
Included for comparison purposes only.
-------
affect the durability or bead retention of applied paints, and paints
21
can be formulated with substitutes to maintain film thickness. However,
solvent substitution would effect the dry time of the applied paint. For
paints formulated with methylene chloride, substitution of another solvent
would result in a slower drying paint, since none of the potential substitutes
evaporate as fast as methylene chloride. Reformulation of paint originally
using 1,1,1-trichloroethane with acetone and hexanes would decrease the dry
time, while reformulation with methyl ethyl ketone or toluene would result
in longer dry times. In general, the impact of solvent substitution on the
20 21
quality of traffic paints is not considered to be significant. ' '
4.2.2.3 Resource Availability
Since chlorinated solvents represent such a small proportion of the
solvents used in the formulation of traffic paints, it is anticipated that
there will be an adequate supply of substitute solvents.
4.3 ECONOMIC ANALYSIS OF SUBSTITUTES
This section analyzes the economic feasibility of substitutes for
methylene chloride and 1,1,1-trichloroethane in paint formulations processes.
For the purposes of this study, the economic analysis deals only with
estimating the relevant costs of using substitutes. No attempt is made to
assess the user's ability to pay these costs. The cost categories analyzed
are costs attributable to a decline in product quality and the capital and
annualized operating costs of using a substitute.
4.3.1 Industry Structure
Paint formulation is a production process within the coatings and
allied products industry. This industry has three broad sub-groups:
architectural coatings, product coatings OEM (original equipment manufacturers),
and special purpose coatings. The processes with which this analysis is
concerned, aerosol paints and traffic paints, are grouped under the special
purpose coatings category. As shown in Table 4-3, both aerosols and traffic
paints represent a relatively small portion of the coatings industry in
terms of production.24 Aerosols represent 0.5 to 0.6 percent of production,
while traffic paints represent 4.5 percent. In 1977, aerosol purchases
4-10
-------
TABLE 4-3. 1979 PRODUCTION OF SURFACE COATINGS
24
Type
Amount
(106 liters)
Industrial
Architectural
Special purpose
Industrial maintenance coatings
Traffic paint
Auto refinishing
Other refinishing
Miscellaneous
Aerosols
Other miscellaneous
Total special purpose
TOTAL
1,552
1,628
107
166
134
34
19 - 23
83 - 87
547
3,727
4-11
-------
totaled $123.5 million compared with total coatings purchases of $6.12 billion,
or approximately 2 percent of the total value of purchases. Traffic paint
represented 0.6 percent of the total value of purchases in 1977.
Table 4-4 summarizes estimated employment and financial data for the industry
for 1980.
Paint formulation takes place in approximately 1,150 to 1,300 companies
which operate approximately 1,600 manufacturing facilities. The geographical
and size distribution of paint manufacturing facilities that responded to a
survey of the industry conducted by the Environmental Protection Agency are
listed in Table 4-5. The results of this survey showed that the industry
contains a large proportion of small plants with a concentration of plants
in California (14 percent), Illinois (8 percent), New York (8 percent),
27
Ohio (7 percent) and New Jersey (8 percent).
4.3.2 Market Penetration of Substitutes
The Technical Analysis Section points out that the substitutes for
halogenated solvents in aerosol paints and traffic paints are not products,
but rather reformulation which could include adding a number of new chemicals.
Thus, an analysis of the market penetration of candidate substitutes is not
feasible. It can be said, however, that there are a number of reformulation
possibilities and the solvents required are known to be commonly used and
commercially available.
4.3.3 Industry Trends
The trend in the coating industry is toward consolidation with larger
and fewer companies. While capital and technology requirements have not
been significant barriers to entry in the past, increasing capital costs
28
and energy costs indicate a decline in the number of smaller companies.
It is not known, however, whether this trend will significantly affect the
aerosol and traffic paint sectors of the industry. Substitute processes
probably would be more easily accomplished by larger companies who have the
financial and personnel requirements to accommodate such a change. Traffic
paints probably will remain at a stable production level as their demand is
derived from road construction and maintenance activities. Governmental
4-12
-------
TABLE 4-4. 1980 PROFILE: PAINTS AND ALLIED PRODUCTS26
SIC Code: 2851
Value of industry shipments (106 $) 9,335
Value added (106 $) 4,014
Total employment (103) 59.5
Number of establishments, total (1977) 1,579
Number of establishments with 20 employees
or more (1977) 653
Exports as a percent of product shipments 3.3
Imports as a percent of apparent consumption 0.6
Compound annual rate of change, 1975-80:
Value of product shipments 12.9
Value of exports 15.8
Value of importsb 20.0
Total employment (%) -0.1
Major producing States:
California, Illinois, Ohio, New Jersey, Texas
almports divided by product shipments plus imports minus exports.
bRates of change based on current dollars.
4-13
-------
TABLE 4-5. GEOGRAPHICAL DISTRIBUTION OF PAINT PLANTS27
Number of plants
EPA Region
Region I
Connecticut
Naine
Massachusetts
ke« Hampshire
Rhode Island
Vermont
Total
Region 11
he* Jersey
he. Tort
Puerto Rico
Virgin Islands
Total
Region 111
Delaware
D.C.
Maryland
Pennsylvania
Virginia
West Virginia
Total
Region IV
Alabama
Florida
Georgia
Kentucky
Mississippi
North Carolina
South Carolina
Tennessee
Total
Region v
Illinois
Indiana
Michigan
Minnesota
Ohio
Wisconsin
Total
Re;1=r. VI
Arkansas
Louisiana
Ne« Keiico
Oklahoma
Tetas
Total
Region Vil
!o-a
Kansas
Missouri
Nebraska
Total
Region VIII
Colorado
Montana
North Dakota
Sough Dakota
Utah
Uyoning
Total
Region IX
Arizona
California
Hawaii
Nevada
Total
Region X
Alaska
Idaho
Oregon
Washington
Total
Accumulative Total
Total
10
3
54
3
5
"77
112
log
6
0
T7I
3
0
?0
66
13
C
TTB
12
69
35
22
S
20
5
17
IB
106
34
47
19
!03
3*
3«5
7
15
3
9
SB
"57
13
10
SI
2
~H '
n
3
0
1
t
TB
6
196
0
I
7B3
1
2
20
22
~K
1.374
0-20
enployees
6
3
36
2
4
-si
60
S4
3
0
1T7
0
0
e
40
6
-57
6
59
20
5
4
9
3
Til
50
22
25
12
60
26
TST
5
11
2
7
Ji
T?
8
6
30
2
TS
e
3
0
1
3
"I?
4
123
0
1
T75
1
2
14
16
T3
S48
20-100
employees
4
0
16
1
1
-73-
37
17
2
0
-R
3
0
10
19
7
li
4
E
10
13
1
7
1
6
TB
38
B
16
6
31
6
TB5
1
t
1
I
-if
4
2
ie
0
~n
3
0
0
0
1
0
2
57
0
0
T5
0
0
6
~rc
396
Over 100
employees
0
0
1
0
0
0
10
6
1
0
T7
0
0
2
6
0
-8
2
0
4
4
0
3
1
~lf
15
4
5
1
10
1
~5E
l
0
0
0
6
1
2
5
0
-B
0
0
0
0
0
0
0
0
12
0
0
-J7
0
0
0
0
—5
105
Not
indicated
0
0
1
0
0
0
5
2
0
0
0
0
0
1
0
0
0
2
1
0
0
1
0
_0
3
0
1
0
2
1
T
0
0
0
1
C
0
0
0
0
T
0
0
0
0
0
0
~B
0
4
0
0
~
0
0
0
0
-5
25
4-14
-------
budgets for these activities are expected to remain stable for the next few
29
years with a greater emphasis on maintenance than on new construction.
Table 4-6 illustrates the estimated trend for coatings and allied products
through 1981. While aerosols and traffic paints are not listed as distinct
categories, it is assumed that they will keep their relative share of
demand.
4.3.4 Product Quality
The Technical Analysis Section reports that substitutes for methylene
chloride in aerosol paints are not likely to alter product quality significantly.
Product quality in aerosols for the general public is primarily related to
the convenience of being able to purchase a small amount of paint for a
specific job. The quick-drying characteristics of aerosols which produces
a smooth, even finish dominates retail advertising strategy. This characteristic
is equally important to industrial users. Any reformulation which would
detract from the quick drying quality of aerosols probably would cause some
shift away from aerosol usage. Since there are a number of reformulation
possibilities, however, no product quality decline is foreseen. Consequently,
no costs are attributed to substitution for this category. As in aerosols
there are no major technical constraints to reformulation in traffic paints
and no decline in product quality is foreseen. Thus, there are no substitution
costs attributable to a change in product quality.
4.3.5 Capital and Annualized Operating Costs
Reformulation would not require the purchase of new production equipment.
Thus, no capital costs are associated with substitution. The primary costs
attributable to reformulation are those associated with research and
development and re-printing of labels. Research and development costs are
primarily expenses for labor and materials. Labor estimates required to
complete reformulation vary from 12 to 15 manhours per reformulation to 130
to 160 manhours per reformulation. ' There is insufficient data to
place a dollar value on these estimates. Cost estimates for label changes
vary from "negligible" to $6000 per label.9'32
4-15
-------
TABLE 4-6. PAINTS AND ALLIED PRODUCTS: TRENDS AND PROJECTIONS 1975-8128
(millions of current dollars, except as noted)
Item
Industry (SCI 2851)
Value of shipments1
Value added
Value added per production
worker-hour (J)
Total employment (000)
Production workers (000)
Average hourly earnings (Oec.--$)
Year-to-year percent change in average
hourly earnings (Dec. -Dec.)
Capital expenditures
4* Product (SIC 2851)
!-• Value of shipments5
en
Producers Price Index (Dec)6
Year-to-year percent change in
Producers Price Index (Dec. -Dec.)6
Trade
Value of exports
Value of imports
1975
5,150
2,126
34.69
59.9
31.1
5.19
11.6
121.6
4,672
170.2
5.2
137.3
21.2
1976
5.931
2,562
40.09
60.4
31.9
5.59
7.7
122.4
5,415
177.3
4.2
170.9
32.3
1977
6,630
2,821
42.62
61.4
33.0
6.08
8.8
167.4
6,123
185.9
4.9
208.5
38.2
1978*
7,320
3,148
__
61.2
32.6
6.50
6.9
--
6,715
199.1
7.1
221.7
39.9
19792
8,564
3,683
__
61.2
32.1
6.98
7.4
--
7,857
210.7
5.8
248.2
49.7
19802
9,335
4,014
..
59.5
30.7
7.30*
6.7"
—
8,564
236. 87
15. 37
286
53
Percent
change
1979-802
9
9
__
-3
-4
--
„_
--
9
--
~
15
7
Percent
change
1981' 1980-81 3
10,300 10
4,429 10
« — —
„
--
--
__
"
9,450 10
_.
—
315 10
60 12
-- Not available.
'Value of all products and services sold by the paints and allied products industry (SIC 2851).
'Estimated except for hourly earnings, price indexes, and 1978-79 trade data.
'Forecast.
"As of June 1980; year-to-year percent change is for June 1979 to June 1980.
5Value of shipments of paints and allied products produced by all industries.
6December 1967 is the base period for index.
7As of July 1980; year-to-year percent change is for July 1979 to July 1980.
Source: Bureau of the Census (Industry and trade data); Bureau of Labor Statistics (hourly earnings and price indexes). Estimates and forecasts
by the Bureau of Industrial Economics.
-------
Reformulation is not expected to cause major changes in the annualized
operating cost of production. As shown in Table 4-7, the price of substitute
chemicals for methylene chloride is lower in many cases; however, since
substitution may not be on a one-for-one basis by either weight or volume,
these figures cannot be used to estimate changes in operating costs.
Substitute solvents are generally less expensive on both weight and volume
bases, and companies that have replaced methylene chloride in their aerosol
formulations generally have realized a reduction in the cost of formulation. ' '
Substitution costs for traffic paints are not expected to be significant.
As in aerosols, no capital purchases would be required. Reformulation
costs are expected to be small because review and evaluation is an ongoing
process in the formulation of traffic paints. It has been estimated that
on the average, 30 percent of the manufacturing costs of traffic paint is
due to the cost of the solvent. Comparative costs of solvents for traffic
paint are listed in Table 4-7. As in aerosol formulations, since substitution
of solvent is not likely to be carried out strictly on a one-for-one weight
or volume basis, the effect of substitution on the cost of manufacturing
paint cannot be determined specifically. However, because potential
substitutes are less expensive than 1,1,1-trichloroethane and methylene
chloride, a reduction in cost can be anticipated.
4.4 CONCLUSION
Substitution for halogenated solvents in aerosol paints must be done
on a case-by-case basis. In aerosol paints, the only significant costs are
those associated with reformulation. Among these are the costs for
personnel and materials in the research and development of new formulations.
Labor estimates vary from 12 to 15 manhours per reformulation to 130 to
160 manhours per reformulation. This is likely to be a one-time cost.
Given the apparent by adequate supply of substitute chemicals, it is not
likely that recurring production costs will rise appreciably after substitution.
The absence of any requirements for new capital equipment for aerosols is
important. In an economic sense, substitution in aerosol paints would
require a minor shift in research and advertising resources. Labeling
changes occur periodically regardless of whether a new formula is present.
Thus, the total impact might best be described as a reallocation of
4-17
-------
TABLE 4-7. PRICES OF SOLVENTS34
Solvent
Methanol
Ethanol
Isopropanol
Acetone
Methyl ethyl ketone
Methyl acetate
Ethyl acetate
Hexane
Heptane
Toluene
Xylene
Methyl ene chloride
1,1,1-Trichloroethane
Cost3
$ per kilogram
0.25
0.64
0.64
0.64
0.77
0.79
0.40
0.40
0.46
0.46
0.67
0.68
$ per liter
0.20
0.52
0.50
0.50
0.62
0.71
0.27
0.28
0.40
0.40
0.89
0.90
aPrices first quarter 1981.
4-18
-------
financial resources that would have occurred anyway. Substitution might
require the transition to come about sooner, but it is not likely to be the
only cause.
The majority of traffic paints are based on alkyd resin systems.
Solvents typically used include aromatics, esters, and alcohols. Chlorinated
solvents account for only nine percent of total consumption. Substitution
for halogenated solvents in traffic paints appears to be reasonable from
the standpoint of costs. The only costs would be due to reformulation and
these are expected to be small because review and evaluation is an ongoing
process.
4-19
-------
4.5 REFERENCES
1. Huber, J.E., ed. The Kline Guide to the Paint Industry. Fairfield, NJ.
Charles H. Kline and Co., Inc. 1978. p. 28-47.
2. Martens, C.R. Pigments, Paints, Varnishes, Lacquers and Printing Inks.
In: Reigel's Handbook of Industrial Chemistry. J.A. Kent, ed. New
York, Van Nostrand Reinhold Co. 1974. p. 653-666.
3. Personal Communication. E. Anderson, GCA Corporation with J. Zacharias,
National Paint and Coating Association, Washington, DC. October 10, 1981.
4. McCartin, T., Materials Balance for Methyl Chloroform, JRB Associates,
McLean, VA. January 1980.
5. EPA Research Request No. 8. Use No. 15: Solvents in Paints and Allied
Products. Summary of Level III Study Results.
6. Personal Communication. E. Anderson, GCA Corporation with R. Johnson,
Duplicolor Products Inc., Elk Grove Village, IL. November 19, 1981.
7. Personal Communication. E. Anderson, GCA Corporation with G. Kass,
Krylon Department, Border Chemical Co., Columbus, OH. November 23, 1981.
8. McCartin, T., Materials Balance for Methylene Chloride, JRB Associates,
McLean, VA. January, 1980.
9. Ford, G.F. A New Decade. Aerosol Age 26(7):23. July 1981.
10. Personal Communication. E. Anderson, GCA Corporation with D. Dahm,
Illinois Bronze Paint Co., Chicago, IL. December 1, 1981.
11. Downing, R.C. Theory and Practice of Aerosols. In: Aerosols: Science
and Technology. H.R. Shepard, ed. New York, NY. Interscience Publishers,
Inc. 1961.
12. Garden, J.L. and J.P. Teas. Solubility Parameters. Treatise on Coatings
Volume 2, Part II: Characterization of Coatings: Physical Techniques.
R.R. Myers and J.S. Long. New York, NY. Marcel Dekker. 1976.
13. Chem Central Physical Properties of Common Organic Solvents and Chemicals.
1980.
14. EPA Research Request No. 8. Use No. 15. Solvents in Paints and Allied
Products. Summary of Level II Study Results.
4-20
-------
15. Sanders, P.A. Principles of Aerosol Technology, New York, Van Nostrand
Reinhold Company. 1979.
16. Personal Communication. E. Anderson, GCA Corporation with G. Leep,
Seymour of Sycamore, Sycamore, IL, December 4, 1981.
17. Sausaman, O.K. A Practical Approach to Solvent Applications in Coatings
and Inks. Solvents Theory and Practice. R.W. Tess, ed. Washington, DC.
American Chemical Society. 1973.
18. EPA Research Request No. 8. Use No. 15; Solvents in Paints and Allied
Products. Summary of Level II Study Results.
19. Personal Communication. E. Anderson, GCA Corporation with P McKenna
Plasti-Kote, Medina, OH. October 15, 1981.
20. Personal Communication. E. Anderson, GCA Corporation with J. Adkins,
Baltimore Paint, Baltimore, MD, November 20, 1981.
21. Personal Communication. E. Anderson, GCA Corporation with F. Smith,
Ennis Paint Manufacturing Company, Enm's, TX., November 24, 1981.
22. Personal Communication. E. Anderson, GCA Corporation with D. Cooper,
Prismo Universal, November 24, 1981.
23. Chatto, D.R. et al. Development of Specifications of Hot and Cold
Applied Traffic Paints. Sacramento, CA. California State Department of
Transportation. September 1975.
24. Personal Communication. E. Anderson, GCA Corporation with J. Zacharias,
National Paint and Coating Association, Washington, DC. October 22, 1981
25. Personal Communications. H. Rollins, GCA Corporation with D. Rosse,
U.S. Department of Commerce, Washington, DC. December 17, 1981.
26. U.S. Department of Commerce. 1981 U.S. Industrial Outlook. U.S
Government Printing Office. Washington, DC. January 1981. p. l'55.
27. U.S. Environmental Protection Agency. Development Document for Effluent
Limitations Guidelines and Standards for the Paint Formulating Point
Source Category. Washington, DC. Publication No. EPA-440/l-79/049b
December 1979.
28. Reference 26, p. 156.
29. Personal Communication. H. Rollins, GCA Corporation with H. Rhudy
North Carolina Department of Transportation, Raleigh, North Carolina
December 17, 1981.
30. Personal Communication. E. Anderson, GCA Corporation with J. Marchbank,
bherwin Williams, Spray-on Division. November 24, 1981.
4-21
-------
31. Personal Communication. E. Anderson, GCA Corporation with Bartlep,
Rustoleum, Chicago, IL, December 8, 1981.
32. Personal Communication. E. Anderson, GCA Corporation with G. Kunz,
Sherwin Williams, Cleveland, OH, November 24, 1981.
33. Personal Communication. E. Anderson, GCA Corporation with F. Smith,
Emmis Paint Manufacturing Company, Ennis, TX, December 11, 1981.
34. Chemical Marketing Reporter, Schnell Publishing Company, New York, NY.
March 31, 1981.
4-22
-------
5.0 FABRIC SCOURING
5.1 GENERAL DESCRIPTION OF USE
5.1.1 Process Description
Fabric scouring is used to remove foreign substances remaining on
textile fibers or picked up during production of the fabric. Fabric
scouring can be performed by either of two methods: aqueous scouring or
solvent scouring.
Aqueous scouring of fabric may be accomplished in batch or continuous
processes, with continuous scouring being the process more frequently
used. In one continuous open-width fabric scouring process, the fabric
dips into a tank containing detergent and then passes through a pneumatically
loaded nip to ensure thorough penetration of the liquor into the fabric.
It is then plaited down into a tank containing wash liquor. The fabric
sinks through the liquor and is drawn from the bottom of the pile by
rollers through opening scroll rolls and a centralizing device onto an
endless mesh belt onto which it is held by suction boxes situated under
the belt. While on the belt the fabric is subjected to high pressure
sprays of rinsing liquor. The suction boxes draw the rinse liquor
through the fabric, removing most before it leaves the belt at which
p
point the fabric is given a final light pressing.
Scouring of textile materials with solvents has been done commercially
for several years. There are two solvent processes for scouring textiles:
the batch process and the continuous process. Batch solvent processing
machines have a system for heating the liquor and four to six tanks for
clean solvent, rinse liquors and finish liquors. The fabric is contained
in a perforated drum that rotates in the solvent which is being circulated
through the drum. The solvent liquors are removed from the fabric by
centrifuging. Fabrics are dried by hot air circulation, and solvent is
5-1
-------
recovered by condensation and carbon adsorption. Contaminated solvent
is cleaned by distillation. Continuous solvent scouring occurs in a
machine similar to the one depicted in Figure 5-1. Fabric is fed on
rollers to the solvent scouring unit. Here the fabric can be dipped or
sprayed with cold solvent, or immersed in hot vaporous solvent. The
fabric is generally supported and tensionless when it is scoured.
Following the scouring process it is wrung and fed to the drying operation.
Following drying, the fabric may be folded, rolled, or sent to a dyeing
4
process.
Solvent scouring is used mostly for the cleaning of synthetic knit
goods prior to finishing. In knit synthetic fabrics, the primary impurities
removed are knitting and coning oils applied to the yarn to facilitate
knitting. Solvents are highly effective in removing these oils but
typically do not remove many of the chemicals that are employed in the
preparation of woven goods. Thus, solvent scouring is generally limited
to the knit fabric segment of the textile industry.
Perch!oroethylene is the solvent most frequently used in solvent
scouring. Trichloroethylene is also used, and recently trichlorotrifluoro-
ethane (CFC-113) has come into use. '6 The extent to which these other
solvents are used is not known.
5.2 DESCRIPTION OF SUBSTITUTES
Substitutes for trichloroethylene, perchloroethylene and CFC-113 in
fabric scouring can be considered as two categories: organic solvent
substitutes and aqueous-based substitutes. The organic solvent substitutes
can be substituted directly for trichloroethylene, perchloroethylene, and
CFC-113 in the solvent scouring process. The aqueous-based substitutes are
used in an aqueous scouring process which can be substituted for the solvent
scouring process.
Organic solvents that have been reported to be used in fabric scouring
include benzene, xylenes, petroleum solvents, and 1,1-dichloroethylene.7'8
Although these solvents have been identified as substitute solvents, none
are presently known to be used in fabric scouring.9'10 Consequently, no
information concerning the technical and economical feasibility of these
solvents as substitutes was obtained.
5-2
-------
FABRIC
FEED
SOLVENT
SCOURING UNIT
PAD
DRYING AND
SOLVENT RECOVERY
FABRIC
DELIVERY
Figure 5-1. Continuous solvent scouring range.
Aqueous-based substitutes to solvent scouring are aqueous scouring
treatments using alkali reagents and anionic surfactants or nonionic
surfactants to remove impurities on the fabric.11 Aqueous scouring is
currently used in the textile industry for scouring of fabrics.
5.3 TECHNICAL ANALYSIS OF SUBSTITUTES
This section analyzes the method of substituting aqueous scouring
for scouring with perchloroethylene, the degree to which aqueous systems
can be substituted for solvent scouring, and the availability of equipment
and materials required to convert to aqueous scouring. This section only
discusses the feasibility of substituting aqueous scouring for scouring
with perchloroethylene, since perchloroethylene is the halogenated solvent
used most often. Although only the substitution of aqueous scouring for
solvent scouring with perchloroethylene is discussed, the information
presented generally applies to the substitution of aqueous scouring systems
using trichloroethylene and CFC-113. CFC-113 does have certain advantages
over perchloroethylene. Its high volatility permits the solvent to be
completely removed from stripped knitting oil so the oil can be used as a
fuel or recycled to the knitting step. No information is available on the
technical feasibility of other potential organic solvent substitutes.
Also, the discussion in this section is based on the continuous scouring
process since there is insufficient information available to evaluate
substitution using batch processing operations.
5-3
-------
5.3.1 Method of Substitution
The substitution of aqueous scouring for solvent scouring necessitates
equipment replacement. The equipment to be replaced is dependent on the
processes to which the fabric will be subject after scouring. In solvent
scouring, the fabric leaves the process dry, while after aqueous scouring
the fabric is wet. When the next step in the processing of the fabric
is aqueous processing, as in the dyeing process, the wet fabric coming
from the aqueous scourer need not be dried. In this case the solvent
scouring range would be replaced only by a machine designed for aqueous
scouring. However, if the fabric needs to be dry for the next process,
as in fabric printing, or if scouring is the last process in the finishing
of the fabric, which may be the case for yarn dyed goods, then in addition
to substituting the aqueous scourer for solvent scouring equipment, a
1 o
dryer needs to be added.
5.3.2 Degree of Substitution
The degree to which aqueous scouring can be substituted for solvent
scouring depends on its effectiveness in removing knitting oils from the
cloth and the effect that substitution has on the processing rate.
Knitting oils applied to lubricate synthetic yarn to facilitate knitting
are the primary substances to be removed from synthetic knit fabric.
Table 5-1 shows examples of oil removal effectiveness of CFC-113 for
various types of fabrics. Residual oil levels of 0.05-0.10 percent
generally can be achieved. Scouring of polyester fabrics with perchloro-
ethylene with an initial oil content of 4 percent has resulted in residual
oil contents 0.05 to 0.3 percent.
Aqueous scouring is generally less effective in removing oils.
Aqueous scouring using alkali reagents removes oils by the formation of
soap with free fatty acids or by the decomposition of oils with the
formation of soap as part of the reaction. The soap then behaves as an
emulsifying agent and removes those substances on which the alkali has
14
no chemical action. Aqueous scouring on the average results in residual
oil concentrations of 0.3 to 0.4 percent by weight.
5-4
-------
TABLE 5-1. EXAMPLES OF OIL REMOVAL EFFICIENCIES FOR CFC-1136
tn
i
tn
Fabric
100% Polyester Jersey Crimplene
100% Polyester Single Knit
100% Texturized Polyester Double Knit
100% Texturized Polyester Double Knit, Yarn Dyed
100% Polyester Double Knit, Processed in Tubular Form
60/40 Type 54 Dacron Polyester Fiber/Type 66 Hyl.cn Kni.t
100% Type 66 Nylon Knit
100% Qiana Knit, Texturized Yarn
100% Polyester Woven Goods, Type 54 Spun Dacron Face;
Type 242 Spun Dacron Back
100% Polyester Woven -- Spun Yarn Warp, Texturized Yarn Fill
20/80 Polyester/Wool Woven
% Oil
Before
2.40
2.90
1.60
1.00
2.20
0.35
5.40
4.30
2.20
0.40
2.30
on fabric
After
0.05
0.05
0.05
0.05
0.10
0.05
0.20
0.10
0.10
0.10
0.20
-------
While aqueous scouring does not have oil removal effectiveness
915
equivalent to that of solvent scouring, it performs an adequate job. '
Higher residual oil in a fabric may make the fabric resistant to dye or
print paste, but levels under 0.5 percent typically do not cause significant
1 ? 1 *i
problems. DuPont has commented, however, that this level is subjective,
and does not apply across-the-board. Lower residual oil levels are
beneficial when fabric is heat set. The lower oil residue reduces yellowing
and oil "mist" thus helping to maintain occupational standards. While
aqueous systems are not as effective as solvent scourers in removing
knitting oils, they are more versatile. Aqueous systems can remove
impurities in cotton that solvents cannot, and thus can be used for
scouring cotton-synthetic blends as well as 100 percent synthetics.
Aqueous scourers can generally achieve process rates comparable to those
of solvent scourers. Thus, in the case where drying of the aqueous scoured
fabric is not necessary, substitution of aqueous systems for solvent would
not have an impact on processing time. In the case where the aqueous
scoured fabric must be dried prior to the next process step, the effect
that the addition of this step would have on production time would depend
on the number of shifts per day that the plant operates. Typical drying
time is about one hour, so plants operating one eight-hour shift daily
would suffer a 12.5 percent decrease in daily production of fabric; plants
operating two shifts per day would experience a 6.3 percent decrease in
daily production; while plants operating at three shifts per day (essentially
a continuous operation) would not experience any appreciable decrease in daily
production.
5.3.3 Resource Availability
The technical feasibility of substituting aqueous scouring for solvent
scouring depends upon the resource availability of aqueous scouring machines.
To determine the resource availability of aqueous scouring machines, 13 manu-
facturers and dealers of scouring machines were contacted. Of these
13 manufacturers and dealers, 3 responded and each stated that their company
could produce about 50 aqueous scouring machines per year for a total of at
17 18 19
least 150 machines per year. ' ' There are approximately 214 scouring
20
and bleaching ranges in knitting mills. Since 3 manufacturers can
make 150 aqueous scouring machines annually, it is assumed that the
5-6
-------
other nine manufacturers can make enough aqueous scouring machines,
i.e., about 64 machines annually, to replace all existing solvent scouring
machines at knit fabric mills. The resource availability of aqueous
scourers appears to be adequate and does not appear to be a constraint
to substituting aqueous scouring machines for solvent scouring machines.
5.4 ECONOMIC ANALYSIS OF SUBSTITUTES
For purposes of this study, the economic feasiblity of solvent
substitutes in fabric scouring deals only with describing and estimating
the relevant costs. Two cost categories are analyzed: costs associated
with a decline in product quality, where the decline is attributable to
substitution; and capital and annualized operating costs. No attempt is
made to assess the user's ability to pay these costs.
5.4.1 Industry Structure
Knit fabric mills, where most solvent scouring applications are
found, is a subsector of the textile industry. Trends and projections
for knit fabric mills are presented in Table 5-2.20 The majority of the
fabric industry is located in North Carolina, South Carolina, and Georgia.
In 1980, more than half of all fabric industry employment was located in
these states.
EPA estimates that approximately 1,973 of the 7,200 mills (27.4 percent)
involved in the production of textile goods utilize wet processing. Of
these, approximately 282 finish knit fabric. A breakdown of production
capacities and a geographic distribution of wet processing mills is
?i
shown in Tables 5-3 and 5-4.
5.4.2 Market Penetration of Substitutes
A survey conducted by the U.S. Department of Commerce indicates
that in 1978, 899 scouring and bleaching ranges were in place in the
textile industry, of which 214 were in knitting mills.20 Data to indicate
the breakdown of solvent-based versus water based machines in knitting
mills is not available. Consequently, the market penetration of aqueous
machines has not been determined in this analysis.
5-7
-------
TABLE 5-2. KNIT FABRIC MILLS: .TRENDS AND PROJECTIONS 1975-8020
(in millions of current dollars except as noted)
Item
Industry (SIC 2257-58)
Value of shipments1
Value added
Valued added per production worker-hour ($)
Total employment (000)
Production workers (000)
Average hourly earnings (Dec.--$)
Year-to-year percent change In average
hourly earnings (Dec. -Dec.)
Capital expenditures
Product (SIC 2257-2258)
Value of shipments5
-------
TABLE 5-3. GEOGRAPHICAL DISTRIBUTION OF WET PROCESSING TEXTILE MILLS^1
Manufacturing
Segment
Wool scouring
Wool finishing
Low water use
processing
h'oven fabric
finishing
Knit fabric
finishing
Hosiery
finishing
Carpet
finishing
Stock & yarn
finishing
Nonwoven
manufacturing
Felted fabric
processing
All segments
I
6
20
86
69
27
2
0
33
10
7
260
II
1
2
108
54
58
2
1
19
3
2
250
III
3
4
125
34
45
9
4
31
4
3
262
EPA
IV
3
3
463
155
134
139
39
120
11
3
1,070
Region
V
0
1
11
11
9
5
1
6
7
2
53
VI
3
1
8
3
1
2
4
3
2
0
27
VII
0
1
1
1
2
0
0
1
0
0
6
VIII
0
1
0
2
0
0
0
0
0
0
3
IX
0
0
4
.7
6
0
9
4
1
3
34
X
1
4
2
0
0
1
0
0
0
0
8
All
regions
17
37
808
336
282
160
58
217
38
20
1,973
5-9
-------
TABLE 5-4. PRODUCTION CAPACITY OF WET PROCESSING MILLS21
Manufacturing
segment
Wool scouring
Wool finishing
Low water use
processing
Woven fabric
finishing
Knit fabric
finishing
Hosiery finishing
Carpet finishing
• Stock & yarn
o finishing
Nonwoven
manufacturing
Felted fabric
processing
All segments
Mills within given production
0-2
2
8
10
36
43
94
2
32
3
6
236
2-4
3
9
7
27
26
25
2
47
3
5
154
4-9
0
9
11
33
34
10
7
35
2
2
143
9-13
1
2
19
28
29
5
3
23
4
1
115
13-22
4
1
23
33
48
2
8
25
3
0
147
22-34
2
2
21
21
21
0
5
20
5
0
97
range,
34-45
2
2
7
20
7
0
6
6
2
0
52
Mg/day
45-68
2
0
5
12
9
0
7
7
2
•1
45
68-91
0
0
3
9
5
0
5
1
0
0
23
91+
0
0
2
21
1
0
5
2
1
0
32
Un-
known
1
4
700
96
59
24
8
19
13
5
929
All
mills
17
37
808
336
282
160
58
217
38
20
1,973
-------
5.4.3 Growth Trends
Within the past five years, the synthetic knit fabric industry has
suffered a severe decline in output. Consequently, a concomitant decrease
in the use of solvent scouring has been experienced. In addition, the
shift from 100 percent synthetic to synthetic/cotton blends has decreased
the use of solvent scouring since solvents cannot adequately remove
impurities in cotton and thus are not typically used in the scouring of
5
blends. Major manufacturers and dealers of solvent scouring machines
are no longer carrying them nor have they sold any in the past few
tal
15
1 15 23-27
years. ' ' One dealer stated that only one third of the units
that he sold still are in use.
5.4.4 Product Quality
Product quality in fabric scouring relates to the degree of cleanliness
achieved in a given process. The Technical Analysis Section reports
that aqueous scouring results in residual oil concentrations of 0.3 to
0.4 percent. Industry representatives generally do not believe the
reduced effectiveness of an aqueous system causes significant problems,
since fabrics are only resistant to dye and print paste at levels greater
than 0.5 percent. Consequently, though product quality may decline,
no costs are associated with it.
5.4.5 Capital and Annualized Costs of Substitution
This section estimates capital and annualized costs directly attributable
to substitution. Capital costs include the expense of any new equipment
and the expense of installing and making it operational. Capital costs
are particularly relevant in assessing the economic feasibility of
converting an existing solvent scouring operation to one using and
aqueous systems, since this conversion would necessitate a change in
equipment.
Annualized costs are estimated for both aqueous and solvent systems
for model plant operations. Comparison of these costs shows the additional
cost burden attributable to substitution which will recur annually.
5-11
-------
5.4.5.1 Model Plant Parameters
A model plant for knit fabric finishing with an annual throughput
21
of 5,600 megagrams (6,160 tons) and an operating schedule of three
shifts per day, seven days per week and fifty weeks per year was used in
calculating annual operating costs. A product mix of 25 percent light
weight knits, 50 percent medium weight knits, 25 percent heavy weight
knits (average 0.22 kg per meter) with a width of 1.5 meters was assumed.
Operating costs were compared for two cases: for scouring conducted
prior to a wet processing step where the aqueous scoured fabric does not
need to be dried, and for scouring conducted prior to a dry processing
step where the aqueous scoured fabric needs to be dried.
5.4.5.2 Capital Costs
Capital costs for aqueous scouring equipment and drying equipment
are presented in Table 5-5. Equipment costs are estimates obtained from
manufacturers and dealers. Taxes, freight and instrumentation are
treated as a single component and calculated at 18 percent of equipment
2<
30
29
costs. Installation costs are estimated at 10 percent of equipment
cost.
5.4.5.3 Annualized Costs
Annualized costs for aqueous and perchloroethylene fabric scouring
28 30 31
are based on information supplied by a manufacturer of scouring equipment.
Cost estimates for perchloroethylene scouring are based on performance
28
claims made by manufacturers. Costs estimates for aqueous scouring
are based on actual annualized costs incurred by a textile processing
mill from their use of a continuous, open width washer for scouring knit
fabrics. Annualized costs of drying equipment are estimates obtained
32
from an equipment dealer. The annualized costs are shown in Tables 5-6
and 5-7.
In Case 1, shown in Table 5-6, where aqueous scouring is not followed
by drying, the annual costs of aqueous scouring are 14 percent higher
than those for solvent scouring. While steam and electricity costs are
lower for aqueous scouring by 54 and 60 percent respectively, the costs
of chemicals, process water, and wastewater treatment are 4 times the
cost of solvent and cooling water in solvent scouring.
5-12
-------
TABLE 5-5. CAPITAL COSTS FOR CONTINUOUS AQUEOUS SCOURING FACILITY
Aqueous scouring not followed by drying
Aqueous scouring range3 251,000
Taxes, freight, instrumentation 45,200
Installation0 25,100
Total 321,300
Aqueous scouring followed by drying
Aqueous scouring range3 251,000
Dryerd 140,000
Taxes, freight, instrumentation 70,400
Installation0 39,100
Total 500,500
References 11 and 33.
Equals 18 percent of equipment cost. Reference 29.
°Equals 10 percent of equipment cost. Reference 30.
References 32 and 34.
5-13
-------
TABLE 5-6. COMPARATIVE ANNUALIZED COSTS OF CONTINUOUS AQUEOUS
AND SOLVENT SCOURING
Perch!oroethylene
scouring
Aqueous
scouring
Case 1: Aqueous scouring not
followed by drying.
Operating costs
Steam 285,000
Electricity 49,400
Cooling water 8,640
Solvent 79,700
Process water
Chemicals
Wastewater treatment
Labor
Maintenance
Administration, insurance, & taxes
Subtotal 422,740
Capital recovery8 57,130
Total 479,870
130,000
19,800
17,300
320,000
22,000
assumed equivalent
509,100
37,700C
546,800
Capital recovery factor is based on a 20 year life and 10 percent interest
rate.
Capital recovery is based on an existing solvent scouring machine with an
installed capital cost of $486,400. Reference 35.
cCapital recovery is based on an aqueous scouring machine with an installed
capital cost of $321,000 (see Table 5-5).
5-14
-------
TABLE 5-7. COMPARATIVE ANNUALIZED COSTS OF CONTINUOUS AQUEOUS
AND SOLVENT SCOURING
Perchloroethylene
scouring
Aqueous
scouring
Case 2: Aqueous scouring
followed by drying.
Operating costs
Scourer
Steam
Electricity
Cooling water
Solvent
Process water
Chemicals
Wastewater treatment
Labor
Maintenance
Administration, insurance & taxes
Subtotal
Dryer
Steam
Electricity
Labor
Subtotal
Capital recovery3
Total
aCapital recovery factor is based on a
rate.
285,000
49,400
8,640
79,700
--
--
--
assumed
422,740
--
--
--
--
57,130b
479,870
20 year life and
130,000
19,800
--
--
17,300
320,000
22,000
equivalent
509,100
377,000
18,500
35,600
431,100
58,800°
999,000
10 percent interest
Capital recovery is based on an existing solvent scouring machine with an
installed capital cost of $486,400. Reference 35.
Capital recovery is based on an aqueous scouring machine with an installed
capital cost of $500,500 (see Table 5-5).
5-15
-------
In Case 2, shown in Table 5-7, where aqueous scouring is followed
by drying, annual costs of a facility using aqueous scouring are approximately
twice those for solvent scouring.
'§)
DuPont incorporated by reference annual operating costs of Permaso'i F
versus perch!oroethylene and aqueous scouring. According to DuPont's
calculations, annual operating costs for aqueous systems, perch!oroethylene
®
systems, and Permaso! F systems are $202,000, $177,000, and $99,000
respectively (see Appendix A).
5.5 CONCLUSIONS
Perchloroethylene is the solvent most frequently used in solvent
scouring. Trichloroethylene is also used and recently CFC-113 has come
into use. Several other organic solvents, such as benzene, xylenes,
petroleum solvents, and 1,1-dichloroethylene have been reported as potential
substitute solvents for perchloroethylene, trichloroethylene and CFC-113
in solvent scouring. However, none of these potential substitute solvents
is presently known to be used in fabric scouring, and information concerning
their technical and economic feasibility as substitute solvents is not
available.
A currently used substitute for solvent scouring is aqueous scouring
using solution containing alkali reagents and anionic or nonionic surfactants.
Aqueous scouring does not remove knitting oils from the fabric as well as
solvent scouring; however, aqueous scouring performs an adequate job and
is more versatile since aqueous systems can remove impurities in cotton and
cotton-synthetic blends that solvent scouring cannot remove. The availability
of aqueous scouring machines appears to be adequate to substitute aqueous
scourers for solvent scourers. Aqueous fabric scouring appears to be a
technically feasible substitute to solvent scouring using halogenated
solvents.
Based on the model plant estimates used to develop economic analysis
information, substituting aqueous scouring for solvent scouring would cause
an increase in the annualized operating cost of fabric scouring depending
on whether the aqueous scourer is followed by a dryer. When the solvent
scourer is replaced by an aqueous scourer, the annualized cost increases
5-16
-------
only 14 percent; however, when the solvent scourer is replaced by an aqueous
scourer and dryer, the annual!zed cost increases by about 100 percent. The
economic feasibility of substituting aqueous scouring for solvent scouring
would depend upon whether a dryer was needed with aqueous scouring machine
and the ability of the plant to incur the increase in the annualized cost.
5-17
-------
5.6 REFERENCES
1. Personal Communication. E. Anderson, GCA Corporation with R. Eby,
Keiltex Corporation, Charlotte, NC. December 4, 1981.
2. Haigh, D. The Preparation Processes. In: Dyeing and Finishing Knitted
Goods. Leicester, England, Hosiery Trade Journal.
3. Perkins, Warren S. Textile Solvent Processing: A Literature Survey,
Water Resources Research Institute, Auburn University, Auburn, Alabama,
May 1976.
4. Hofstetter, Hans, H. Solvent Processing for Textiles, W.R.C. Smith
Publishing Company, Atlanta, Georgia, June 1970.
5. Personal Communication. E. Anderson, GCA Corporation with C. Livingood,
Dept. of Textile Chemistry, North Carolina State University. November 13, 1981
6. Bell, D.G. "New Chemical Solvent Opens Ways for Safe, Energy-Conscious
Textile Scouring". Modern Knitting Management 57:32-34, May/June 1979.
7. Hoogheem, T.J., et al. Source Assessment: Solvent Evaporation - Degreasing
Operations, Contract No. 68-02-1874, U.S. Environmental Protection Agency,
Cincinnati, Ohio, June 1978.
8. Matthews, J.C., et al. Screening Study on Justification of Developing New
Source Performance Standards for Various Textile Processing Operations,
Contract No. 68-02-0607-11, U.S. Environmental Protection Agency,
Research Triangle Park, North Carolina, August 1974.
9. Personal Communication. E. Anderson, GCA Corporation with B. Walter,
American Permac Inc., Plainview, NY. December 10, 1981.
10. Personal Communication. E. Anderson, GCA Corporation with N. Stuart,
Institute of Textile Technology. Charlottesville, VA. December 9, 1981.
11. Oyabu, N. Desizing and Scouring of Synthetic Fibers. Japan Textile
News 269: 33-34. April 1977.
12. Personal Communication. E. Anderson, GCA Corporation with R. Ramsey,
E.I. du Pont de Nemours and Company, Wilmington, DE. December 3, 1981.
13. Kolb, K. "Practical Experience with the Continuous Solvent Scouring
Machine for Knit Goods." Textile Solvent Technology - Update '73.
American Association of Textile Chemists and Colorists. Research
Triangle Park, NC. 1973. pp. 91-96.
5-18
-------
14. Marsh, J.T. Textile Science, Champman and Hall Ltd., London, England,
1949.
15. Personal Communication. E. Anderson, GCA Corporation with B. Falk, ITM,
Ltd., December 10, 1981.
16. Davison's Textile Blue Book, 114th Edition, Davison's Publishing Co.,
Ridgewood, NJ, 1980. p. 566.
17. Personal Communication. E. Anderson, GCA Corporation with C. Tie,
Mega Marketing, Inc., Boonton, N.J. December 29, 1981.
18. Personal Communication. E. Anderson, GCA Corporation with M. Koledo,
Briggs and Lambard, Springfield, VT. December 29, 1981.
19. Personal Communication. E. Anderson, GCA Corporation, with M. Hazen,
Morrison Textile Machinery Co., Ft. Lawn, SC. December 29, 1981.
20. U.S. Department of Commerce. Chapter 34: Textiles. In: Industrial
Outlook. U.S. Government Printing Office. Washington, DC. January 1981.
21. U.S. Environmental Protection Agency. Development Document for Effluent
Guidelines and Standards for the Textile Mills Point Source Category.
Washington, DC. Publication No. EPA-440/l-79/022-b. October 1979.
22. U.S. Department of Commerce. 1977 Census of Manufacturers: Textile
Machinery in Place. Washington, DC. 1980.
23. Personal Communication. E. Anderson, GCA Corporation with W. Holmes,
Riggs and Lombard, Inc., Lowell, MA. November 18, 1981.
24. Personal Communication. E. Anderson, GCA Corporation with B. Lyttle,
Brian Lyttle, December 9, 1981.
25. Personal Communication. E. Anderson, GCA Corporation with Tekmatex,
Inc., Charlotte, NC. November 18, 1981.
26. Personal Communication. E. Anderson, GCA Corporation with H. Williams,
Bruckner Machinery Corporation, Spartanburg, SC. November 18, 1981.
27. Personal Communication. E. Anderson, GCA Corporation with D. Sangster,
Schmidt Manufacturing Corporation, Greensboro, NC. December 9, 1981.
28. Ramsey, R.B. Fabric Scouring with Trichlorotrifluoroethane. Presented
at the National Technical Conference of American Association of Textile
Chemists and Colorists. October 1979.
29. United States Environmental Protection Agency. Petroleum Dry
Cleaners - Background Information for Proposed Standards (Preliminary
Draft). Office of Air Quality Planning and Standards. Research Triangle
Park, NC. November 1981.
5-19
-------
30. Personal Communication. E. Anderson, GCA Corporation with R. Mantry,
Textile Machinery, Charlotte, NC. December 7, 1981.
31. Letter with enclosures. R.B. Ramsey, E.I. du Pont de Nemours and Company
to E. Anderson, GCA Corporation. December 7, 1981.
32. Personal Communication. E. Anderson, GCA Corporation with P. Krafton, .
Consolidated Engineering, Atlanta, GA. December 17, 1981.
33. Personal Communication. E. Anderson, GCA Corporation with T. Spantinato,
Textile Machinery, Charlotte, NC, December 17, 1981.
34. Personal Communication. E. Anderson, GCA Corporation with D. Forman,
Fab-Con Machinery, Development Corporation, Port Washington, NY,
December 7, 1981.
35. Personal Communication. E. Anderson, GCA Corporation with T. Spantinato,
Textile Machinery, Charlotte, NC, December 4, 1981.
5-20
-------
APPENDIX A
Comments by E.I. du Pont de Nemours & Company
A-l
-------
3PI£
E. I. DU PONT DE NEMOURS & COMPANY
WILMINGTON. DELAWARE 19898
PETROCHEMICALS DEPARTMENT November 5, 1962
Ks. Virginia K. Steiner
Task Manager
U.S. Environmental Protection Agency
Office of Pesticides and Toxic Substances
Waterside Mall
401 M Street, S.W.
Washington, D.C. 20460
Dear Ms. Steiner:
COMMENTS ON THE DRAFT FINAL REPORT FROM GCA CORPORATION
TO EPA ENTITLED "PRELIMINARY ANALYSIS OF POSSIBLE SUBSTITUTES
FOR 1,1,1-TRICHLOROETHANE, TETRACHLOROETHENE,
DICHLOROMETHANE, TETRACHLOROMETHANE, TRICHLOROETHENE, AND
TRICHLOROTRIFLUOROETHANE," DATED MAY 1982 (GCA-TR-82-46-G)
The Du Pont Company wishes to provide the following
comments on the subject Draft Analysis. Our comments specifi-
cally apply to trichlorotrifluoroethane (CFC-113). I have
arranged our comments into Sections as follows:
1. GENERAL COMMENTS
2. SPECIFIC ADVANTAGEOUS PROPERTIES OF CFC-113
SOLVENTS
3. SPECIFIC COMMENTS ON SOURCE CATEGORIES (END-USES)
4. REFERENCES
A-2
-------
-2-
Reference is frequently made to the subject Draft Analysis and
such references are shown in square brackets, for instance
[p. 1-5] refers to page 1-5 in the Draft Analysis. References
cited in these comments are shown in parenthesis as (HAS, 1979)
Yours sincere
RichardB. Ward
Research Associate
Freon* Products Division
RBW:plt
Attachment
CC: Richard Rehm
GCA Corporation
GCA/Technology Division
Chapel Bill, NC 27514
A-3
-------
COMMENTS ON THE DRAFT FINAL REPORT FROM GCA CORPORATION
TO EPA ENTITLED "PRELIMINARY ANALYSIS OF POSSIBLE SUBSTITUTES
FOR 1,1,1-TRICHLOROETHANE, TETRACHLOROETHENE,
DICHLOROMETHANE. TETRACHLOROMETHANE, TRICHLOROETHENE, AND
TRICHLOROTRIFLUOROETBANE," DATED MAY 1982 (GCA-TR-82-46-G)
1. GENERAL COMMENTS
The Draft Analysis is specifically limited to four
source
categories or end-uses [p. iii]:
Metal Cleaning (which in the Analysis includes cleaning
of printed circuit board assemblies)
Dry Cleaning
Surface Coatings (in which CFC use is insignificant and
therefore is not further addressed in these comments), and
Fabric Scouring
Other solvent uses are omitted from the Analysis and from these
comments.
The report provides a good outline of the uses covered
and of alternative technologies. However, in discussing the uses
involving CFC-113, the Analysis does not include a discussion of
the unique properties of CFC-113 in most of its solvent applica-
tions. It is with regard to discussion of such properties that
we recommend thorough revision.
The unique properties of CFC-113 (see Section 2 of these
Comments) not only justify the use of this more expensive sol-
vent, but also materially increase the difficulty in finding
alternatives to CFC-113. For most uses, economics would force
substitution of cheaper solvents (such as the other chlorinated
A-4
-------
solvents) if process effectiveness, safety, and product quality
and reliability could be maintained at necessary levels. Thus it
follows that CFC-113 tends to be used only in those applications
where nothing else will do the job adequately.
It is this critical evaluation of the adequacy of alter-
natives for CFC-113 that is almost totally omitted in this
Analysis. Although the Analysis correctly notes (p. iiij:
"...halogenated solvents...are often used
because their physical and chemical pro-
perties make them unique in given
situations,"
"...it should be noted that substitution
may not always be feasible," and
•[Substitution] should always be
determined on a case-by-case basis,"
These statements are not applied to the discussion of CFC-113.
Under Metal Cleaning [p. 2-16] it is noted that:
"...there are areas where complete sub-
stitution may be infeasible and halo-
genated solvents must be used."
A careful evaluation would show this to be particularly true in
CFC-113 use, particularly in applications in which several
materials of construction are cleaned simultaneously — such as
in electronics assemblies.
In dry cleaning and fabric scouring, essentially no
attempt is made to distinguish CFC-113 from tetrachloroethylene.
We note* that it is only in references to aerosol
formulations of paints and in Section 5 (Fabric Scouring)
*The copy of the report we received contained no pages 3-29 or
3-30 and thus did not show references 1 to 14 inclusive in
Section 3. The text does not suggest any of the missing
references would materially alter this observation.
A-5
-------
that any indication is made that Du Pont sources of information
have been consulted. Even in the Fabric Scouring section the
report incorrectly assumes [p. 5-3]:
•Although only the substitution of
aqueous scouring for solvent scouring
with perchloroethylene is discussed, the
information presented generally applies
to the substitution of aqueous scouring
[for] systems using...CFC-113."
This is contrary to the information in the cited reference
(Ramsey, 1979). [Reference 28, p. 5-18].
Equally surprising is the apparent absence of any ref-
erence to previous analyses of alternatives to CFC-113, such as
by the National Academy of Sciences (NAS, 1979) or the Rand
Corporation (Rand, 1982), in which both the unique properties of
CFC-113, and the importance of these properties in discussing
alternatives to CFC-113, were better recognized. The opportunity
for this Analysis to build on such earlier reports and the
comments prepared on these earlier reports (e.g., Du Pont, 1980;
Ward, 1981, 1982) has been overlooked.
2. SPECIFIC ADVANTAGEOUS PROPERTIES OF CFC-113 SOLVENT
CFC-113 finds most of its applications due to its unique
combination of properties. The most obvious are its very low
toxicity, nonflammability, inertness, and volatility. The low
toxicity provides a major safety advantage for workers.
While the advantages of nonflammability are obvious and
are acknowledged in the Analysis [p. 1-6], they are omitted in
economic estimates of alternatives [p. 3-28]. In certain situa-
tions, fire codes may forbid storage and use of flammable sol-
vents no matter what retrofitting is undertaken. An example
might be a city neighborhood dry cleaner at street level in a
multistory, multiple use building.
A-6
-------
The inertness of CFC-113 provides several important
advantages. The inherent stability in use removes the need for
chemical stabilizers, simplifying recycle since stablizers may be
fractionated by distillation or removed when solvent is separated
from water contamination. The mild solvent properties of CFC-113
result in a very broad range of materials being compatible with
the solvent, an essential asset when, for example, multiple
plastics are found in printed circuit assemblies or as trim,
etc., on clothing. While this advantage is hinted at [pp. 2-16,
2-19], it is overlooked elsewhere (pp. 1-5, 2-15, 2-17, 3-1,
5-1].
A further advantage of the inertness of CFC-113 is that
the compound is negligibly photochemically reactive and therefore
CFC-113 emissions do not contribute to smog (EPA, 1980). Hydro-
carbon alternatives do not share this benefit, a point totally
overlooked [e.g., at pp. 2-28, 3-7, 5-2].
The volatility (the compound has a low boiling point of
43°C and a low latent heat of evaporation, 35.07 cal/g) confers a
number of advantages. Energy requirements to maintain boiling
liquid or vapor zones are minimized, cleaned material can be
handled immediately, solvent treated materials are readily dried,
and the convection currents, which tend to increase vapor loss
from equipment containing boiling solvent, are minimized. To an
extent, CFC-113 has essentially an optimum boiling point. Advan-
tages from a lower boiling point (e.g., CFC-11, b.p. 24 C) are,
in fact, more than offset by greater difficulties in containing
the more volatile solvent in most cases, hence the preponderant
use in the U.S. of CFC-113 versus CFC-11 as a solvent. The
importance of this advantageous volatility is overlooked [e.g.,
at pp. 1-5, 2-14, 2-15, 2-16, 2-27].
Other physical properties of CFC-113 used to advantage
include the high molecular weight (187.5), high liquid density
A-7
-------
(1.565 g/cm at 25°C), low surface tension (17.3 dynes/cm at
25°C), and the formation of azeotropes with several more polar
volatile solvents.
The high molecular weight results in a dense vapor
further aiding vapor recycle. The high liquid density, notice-
ably absent in hydrocarbons, aids in the ability of CFC-113 to
•float" off particulate contaminants from surfaces to be cleaned.
The low surface tension aids in the wetting of surfaces
and cleaning of small interstices. This is particularly impor-
tant in comparison with aqueous cleaning alternatives but is not
adequately discussed in the Analysis [e.g., at pp. 1-5, 2-17].
CFC-113 forms azeotropes* with a number of more polar
and volatile compounds such as methanol, ethanol, acetone, and
methylene chloride. These azeotropes are nonflammable and permit
•fine-tuning" of the solvent properties for specific applica-
tions. Almost half of CFC-113 solvent is sold as an azeotrope
— providing a clear example of the preciseness with which
CFC-113-based solvents are tailored for optimum performance in
specific applications. Such azeotropes substantially extend the
value of CFC-113 in removing certain contaminants, soldering
fluxes, etc. [cf., pp. 2-3, 2-8, 2-17].
Further details of the properties of CFC-113 solvent,
azeotropes, and blends are given in the Du Pont Bulletin FS-21
(Du Pont, 1977).
*A mixture in which liquid and vapor phases have the same com-
position and in which, therefore, components are not selectively
concentrated during evaporation or at the boil.
A-8
-------
3. SPECIFIC COMMENTS ON SOURCE CATEGORIES (END-USES)
3.1 Metal Cleaning
Most applications of CFC-113 and its azeotropes and
blends are in the cleaning of products other than simple metal
parts. It is, therefore, unfortunate that this section has been
labeled "Metal Cleaning." Most CFC-113 cleaning applications are
for electronic, medical, and other equipment involving a variety
of materials of construction, intricate shapes including small
interstices and close-packed electronic assemblies, and where
extremely low levels of residues and soil are essential to the
product's end-use and reliability [pp. 1-5, 1-9, 2-1, 2-24].
Separation of these "high technology" cleaning applica-
tions from conventional metal cleaning in two separate source
categories is recommended. Such a revision would permit a
clearer differentiation between the categories in terms of
solvent property requirements and cleaning specifications, etc.
Emulsion cleaning and abrasive blasting are wholly
inappropriate as alternatives for virtually all CFC-113 solvent
applications. Water, unless doped with surfactants, has a high
surface tension (72 dynes/cm versus 17.3 dynes/cm for CFC-113 at
25°C) and thus does not wet surfaces or penetrate interstices as
well. Removal of surfactant residues represents a major techni-
cal difficulty with aqueous systems (Ramsey, 1974, 1975; Keller,
1981). Energy consumption at the consumer's plant is an impor-
tant factor, as are ecological concerns (Ramsey, 1974, 1975;
Obrzut, 1977). It should also be noted that solvent cleaning
processes concentrate soil and contaminants for appropriate dis-
posal, while aqueous processes disperse contaminants [pp. 1-5,
2-15, 2-17].
Many resins and fluxes used in electronic component
assembly cannot be removed by aqueous cleaning.
A-9
-------
The statement [p. 2-8] that solvent degreasing is
•totally ineffective in the removal of...most miscellaneous
contaminants" is incorrect. Such miscellaneous contaminants as
particulates, soil, fluxes, quenching oils and inorganic salts
are removed effectively by CFC-113-based solvents to the most
exacting specifications in space, medical, and communications
related applications. (See Du Pont, 1977).
Compatibility with materials of construction can be ex-
tremely critical. Absorption of solvent can alter capacitance
values or physical dimensions, for instance, and evaporation of
the absorbed solvent may be slow ~ resulting in drifting perfor-
mance or changing tolerances in subsequent testing and use. The
high compatibility of CFC-113 with materials of construction and
its low boiling point frequently make CFC-113 essential in criti-
cal applications involving the cleaning and drying of electronic,
electrical, and mechanical assemblies (NAS, 1979, p. 157). Apart
from flaramability concerns, substitution of aliphatic, aromatic,
or oxygenated solvents would not satisfy the precise solvent
requirement for these exacting applications [pp. 1-5, 2-24, et.
seq.]. Again the concept of "metal cleaning" does not convey the
concept of high technology applications for which CFC-113 sol-
vents are principally used.
The 65/35 weight percent blend of CFC-113 with ethanol
is not an azeotrope lp. 2-31). The composition of the azeotrope
is approximately 96/4 weight percent CFC-113/denatured ethanol
(e.g., Freon* TE Solvent, Du Pont 1977). The 65/35 blend is
intended for cold cleaning or use in specially designed vapor
degreasers. Although the mixture initially has no flash point
when brought to the boiling point, evaporation can result in a
flammable residual solvent. (See Du Pont, 1977, Freon* TE-35
Solvent).
A-10
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There are areas, particularly involving ordinary metal
cleaning, where aqueous cleaning and solvent cleaning are di-
rectly competitive. It appears that examples of substitution of
aqueous techniques for solvent techniques have been selected
[pp. 2-16, 2-17), since examples of the reverse substitution
exist but are not discussed. Aqueous cleaning has replaced
solvents in less exacting applications, where CFC-113 does not
find major, use. For instance, a number of factors have combined
to reduce the proportionate use of trichloroethylene — a rela-
tively strong solvent. As would be expected in a competitive
situation, the market share lost by trichloroethylene has been
divided mainly between other chlorinated solvents and aqueous
processing. It certainly does not follow that most CFC-113
solvent uses can be similarly substituted by aqueous cleaning.
CFC-113 is negligibly photochemically reactive (EPA,
1980) and does not contribute to photochemical smog. Hydro-
carbon and oxygenated solvents act as precursors for smog and
adversely affect ambient air quality [p. 2-28].
The data in Tables 2-1 and 2-6 should be identified as
to year [pp. 2-3, 2-38].
3.2 Dry Cleaning
The most significant factor which is understated is the
fire potential in substituting to a hydrocarbon solvent. As
pointed out in Section 1 of these comments, flammable solvents
may be prohibited in many dry cleaning locations, requiring total
relocation of businesses converting to hydrocarbon use. It is
unfortunate that fire code related costs are omitted from the
cost estimates in Tables 3-10, 3-11, and 3-12 [pp. 3-25, 3-26,
and 3-27]. The cost comparison for most dry cleaning establish-
ments is meaningless with this omission.
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This section also glosses over the advantages of CFC-113
in dry cleaning. The inertness of the CFC-113 solvent make it
more compatible with plastic trim, buttons, etc., and of suede
and leather goods in the dry cleaning process, and can eliminate
the time-consuming necessity to remove such materials from
clothing prior to dry cleaning, and reattachment afterwards [p.
3-1]. The high volatility and low absorption of CFC-113 solvent
into fibers means that the drying step can be carried out under
milder conditions, an important factor for certain fabrics. As a
result, CFC-113 finds special applications in the dry cleaning
industry and should not be equated with perchloroethylene in this
Analysis [pp. 1-6, 3-8].
Hydrocarbon emissions act as precursors for smog, while
CFC-113 does not. This is an important factor in maintaining
national ambient air standards for ozone in the urban
environment.
The data in Table 3-4 should be identified as to year
and referenced [p. 3-15].
3.3 Fabric Scouring
The importance of the unique properties of CFC-113 have
been overlooked in the Analysis. An important factor is the ease
with which CFC-113 can be stripped from the knitting oil. Ramsey
(1979) points out that the high volatility of CFC-113 permits the
solvent to be so completely removed from stripped knitting oil
that this oil can be used as fuel (for a fuel credit) or even
recycled for use in the knitting step (for a larger credit). The
waste disposal costs of the stripped knitting oil are eliminated.
CFC-113 should not be equated to perchloroethylene in this
Analysis [pp. 1-6, 5-3]. .
A-12
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The comment that 'residual oil levels under 0.5 percent
typically do not cause significant problems" is subjective, and
does not apply accross-the-board. Prior to the introduction of
CFC-113 scouring, the higher residual oil levels were accepted
because there was no other choice. The lower residual oil levels
achieved with CFC-113 scouring have been particularly beneficial
when the fabric is subsequently heat set. The lower oil residue
reduces yellowing from residual oil, and reduces oil "smoke" or
"mist" formation in this step. This is important in the work-
place since a 5 mg/m3 8-hour Time Weighted Average (TWA) has been
established by the American Conference of Governmental Industrial
Hygienists for mineral oil mists.
The economic analysis shown in Ramsey (1979) indicates
that the total costs in switching from CFC-113 scouring to a
water process would be substantially greater than the examples
shown in the Analysis Tables 5-6 and 5-7 tpp. 5-14, 5-15].
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4. REFERENCES
*Du Pont Bulletin FS-21: Du Pont Freon* Solvents That Meet
Today's Cleaning Needs, 1977.
*Du Pont: "Comments on the December 1979 Report by the National
Academy of Sciences' Committee on Alternatives for the
Reduction of Chlorofluorocarbon Emissions (CARCE)."
Wilmington, DE, 1980.
EPA, 45 Federal Register, 48941-2, July 22, 1980.
*Keller, J., Improving PWB Reliability While Cutting Soldering
and Cleaning Costs. Assembly Engineering, May 1981, pp.
14-17 (Part 1); June 1981, pp. 14-18 (Part 2); July 1981, pp.
18-21 (Part 3).
National Academy of Sciences: Report of the Committee on Alter-
natives for the Reduction of Chlorofluorocarbon Emissions, in
•Protection Against Depletion of Stratospheric Ozone by
Chlorofluorocarbons." Washington, D.C., 1979.
*0brzut, J. J., Metals Can be Cleaned With Less Energy, Iron Age,
48-50, May 1977.
*Ramsey, R. B., Jr., Cleaning System Selection Under Today's
Ecological and Safety Constraints. Paper presented at
Internepcon Europa, Brussels, Belgium, May 28, 1974.
*Ramsey, R. B., Jr., The Niche for Fluorinated Solvents. Metal
Progress, 71-74, April 1975.
'References so marked are enclosed,
A-14
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*Ramsey, R. B., Jr., Fabric Scouring with Trichlorotrifluoro-
ethane. Presented at the National Technical Conference,
American Association of Textile Chemists and Colorists,
October 1979. (Du Pont Technical Report RP-10).
Rand Corporation: Technical Options for Reducing Chlorofluoro-
carbon Emissions, Mooz, W. E., e_t _al. Santa Monica, CA,
March.1982.
*Ward, R. B. (Du Pont Company), letter/attachments to Mooz, W. E.
(Rand Corporation): •Comments on 'Preliminary Assessment of
Chlorofluorocarbon Emission Reduction Methods, N-1734-EPA,'
July 1981." November 24, 1981.
*Ward, R. B. (Du Pont Company), letter/attachments to Clay, D. R,
(EPA): "Comments on 'Rand Report R-2879-EPA: Technical
Options for Reducing Chlorofluorocarbon Emissions'."
July 13, 1982.
'References so marked are enclosed.
RBW:plt
A-15
-12-
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APPENDIX B
Comments by the Halogenated Cleaning Solvents Association
B-l
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Hologenoted Cleaning Solvents Association
c/o SOCMA. 1075 Central Partc Avenue. Scarsdale. New York 10583
Affiliated with Synthetic Organic Chemical Manulacturers Association. Inc.
January 6, 1983
Mr. Walter Kovalick, Jr.
Director, Integration Staff
Office of Toxics Integration
U.S. Environmental Protection Agency
TS-777
401 M Street, SW
Washington, DC 20460
Re: Draft Substitutes Analysis for
the Halogenated Solvents
Dear Mr. Kovalick:
We are pleased to provide these comments on the draft
preliminary analysis of possible substitutes for 1,1,1-tri-
chloroethane, tetrachloroethylene, dichloromethane, tetra-
chloromethane, trichloroethylene, and trichlorotrifluoroethane
(May 1982) prepared by GCA Corporation.
As you know, HCSA is concerned that EPA has under-
taken regulatory initiatives to control emissions of these sol-
vents to the atmosphere in the absence of sound scientific evi-
dence that such emissions endanger human health or the environ-
ment at ambient concentrations. The Science Advisory Board
review of draft health assessments for the solvents should be
the starting point for any determination of whether regulation
of emissions of these solvents is warranted. We recognize that
the Office of Toxics Integration can play an important role in
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coordinating EPA's overall approach to these solvents, once the
evaluation of their health effects is completed. In this
regard, should it be demonstrated that exposure to halogenated
solvents poses a significant risk to human health, it would be
necessary to evaluate alternatives to such solvents in terms of
the overall risk to human health and the environment posed by
such alternatives. In the absence of such an evaluation, it
should not be assumed that control of the halogenated solvents
would reduce overall risk to human health or the environment.
The comments below are technical in nature. No
attempt has been made to confirm quantitative data appearing in
the analysis. These comments are offered in a spirit of
cooperation to achieve a technically accurate document.
However, as indicated above, we believe that it is premature to
examine substitutes to the halogenated cleaning solvents in the
absence of scientifically sound reasons to believe that current
or expected environmental concentrations of such solvents pose
any significant health or environmental risk.
METAL CLEANING
1. Table 2-1 indicates quantities of solvents much
greater than those which are being consumed currently. Based
on historical sales data, it may be estimated that total sales
of halogenated solvents to metal cleaning operations in 1982
-will be approximately 60 to 65 percent of those shown in this
table.
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2. Some additional parameters important in the
selection of a cleaning process include: factory floor space
available, water availability, waste water treatment availabi-
lity, regulations, ventilation requirements, energy con-
sumption, and waste disposal. These criteria for process
selection could be inserted into the text on page 2-6.
3. Neither organic solvents nor alkaline washing
compounds solubilize the abrasives contained in pigmented draw-
ing compounds, buffing compounds, etc. Solvent degreasing with
spraying or ultrasonic agitation can remove these contaminants
when the media carrying the abrasives are solvent soluble.
When the media are water soluble or soluble in alkaline solu-
tions (soaps, for example) aqueous cleaning can be effective.
The suggestion on page 2-8 that halogenated solvents are not
useful cleaning agents for all such compounds is incorrect.
4. As stated on page 2-11, it is not possible as a
general matter to convert vapor degreasing equipment into
aqueous cleaning equipment. It should also be noted that the
space required for an alkaline cleaning system frequently will
be much greater than that required for a solvent cleaning sys-
tem. Tables 2-9, 2-10, and 2-11 show user energy costs for
alkaline washing that are substantially greater than those for
vapor degreasing. Therefore, increased steam generating capac-
ity may need to be installed or alternative gas or electric
Cheating may be required. The heat and moisture from the washer
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as well as the parts drying section of the washer will need to
be exhausted from the operating area. These exhaust rates are
often so substantial that plant heating costs can be signifi-
cantly affected in the winter, and air conditioning may be
impractical even in plants in the southern United States.
Increased health risks from heat stress, potential skin or eye
injury from alkaline salts or salt solution concentrates, and
risks associated with water pollution should be evaluated rela-
tive to any risks defined for the halogenated solvent cleaning
system which would be replaced.
5. The following quote appears on page 2-15:
Results of the study have shown that under
identical operating conditions and work-
loads, aqueous cleaning of printed circuit
boards can be done up to six times more
effectively than similar solvent-based sys-
tems .
This statement is supported by a reference from Jim Dingman,
Unique Industries, Inc., Sun Valley, California. Art Gillman,
President of Unique Industries, has indicated that Mr. Dingman
is not an employee of Unique Industries but is a sales repre-
sentative for that firm. Mr. Dingman requested the opportunity
to review any quotations of his conversation before release and
has not granted any release. Further, he reports that the
statement made was taken out of context. See attached letter
from Mr. A. Gillman, President, Unique Industries.
Two articles on printed circuit board cleaning are
attached. Attention is called to the cleaning system
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performance chart on page 2 of the article "Are Aqueous Systems
the 'Universal' Solution?". The results and conclusions of the
paper entitled "Organic Surface Contamination — Its
Identification, Characterization, Removal, Effects on
Insulation Resistance and Conformal Coating Adhesion" are also
of particular interest.
6. The statement on page 2-15 concerning "Ct]he
traditionally low cost of halogenated solvents due to compara-
tively inexpensive petroleum feed stocks and energy sources" is
misleading. The halogenated solvents are made from petroleum
feed stocks by the use of chemical process steps, energy, chlo-
rine and, in the case of CFC-113, hydrogen fluoride.
Consequently, their cost will always be several times the cost
of petroleum solvents. Aqueous cleaning compounds, on the
other hand, are based largely on caustic (sodium hydroxide).
Alkaline cleaning solutions are, and have always been, cheaper
than the equivalent quantity of halogenated solvents.
7. The first complete sentence on page 2-16 would
more appropriately be reworded as follows:
Regulatory pressures had not influenced the
selection of a metal cleaning process until
recently. Solvent cleaning, aqueous clean-
ing, and other cleaning processes were cho-
sen solely on their engineer-ing merit.
Listings, regulations, and guidelines,
which have been proposed or adopted in many
cases with inadequate scientific justifica-
tion, have increasingly discouraged the use
of halogenated solvents.
B-6
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8. With reference to section 2.3.1, aqueous systems
are likely to leave residual water on parts cleaned, particu-
larly in recesses. This frequently occurs even in systems
equipped with a dryer stage. The retained moisture can induce
corrosion. When aqueous cleaning solutions must have a strong
alkalinity (pH 10 or greater) to achieve effective cleaning,
chemical attack on aluminum and other reactive metals can be
expected.
9. On pages 2-17 and 2-18, some of the advantages
of combining organic solvent cleaning with aqueous cleaning in
emulsion systems are discussed. However, the text fails to
describe adequately the fact that emulsion cleaners also
inherit the disadvantages of both systems. Emulsion cleaning
liquids, being largely comprised of water, are unsuitable for
electronic parts or electrical assemblies cleaning. As an
aqueous system, emulsion cleaning generally requires more space
and as much or nearly as much energy as alkaline washing, par-
ticularly if the parts require drying, as is common. Both
alkaline washing and emulsion cleaning have much higher user
energy demands than are common in solvent cleaning operations.
Although emulsion cleaning does provide some ability to solubi-
lize solvent soluble soils compared with aqueous systems, this
method of compounding does not increase the solvency of the
solvent employed above that of the pure solvent. Since the
^-
solvent portion of the emulsion is a relatively small
B-7
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percentage, the ability to dissolve solvent soluble soils
before saturating the emulsion cleaner is highly limited.
Solvent emulsion systems are not recoverable by distillation,
contribute to water pollution, and present a substantial waste
disposal burden due to their low load carrying ability for
soil.
The literature reports that the best cleaning is
obtained with the least stable emulsions. In such emulsion
cleaning systems, a separate phase of solvent frequently will
be formed. Solvents employed in emulsion cleaning typically
have flash points and pose some fire hazard. Emulsified sol-
vents will display a vapor pressure and will, therefore, eva-
porate from the emulsion to some extent. As in the case of
aqueous cleaning, high ventilation rates are experienced both
in the washing stages and drying stages of emulsion cleaners.
Therefore, it is unlikely that high concentrations of the sol-
vent vapors will exist in the work atmosphere. Emulsion sys-
tems without ventilation and with higher temperatures employed
must be regarded as sources of possible solvent vapor expo-
sures. Although the emissions of hydrocarbon solvents from
emulsion systems have been ignored in the draft analysis, there
is no doubt that these hydrocarbon vapors contribute to ambient
ozone concentration and may result in adverse health effects
due to smog formation.
B-8
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10. With regard to section 2.3.3, abrasive or non-
chejnical cleaning of metal parts does not represent any signif-
icant alternative to solvent cleaning. This process substan-
tially modifies the surface in many cases, is labor intensive,
and can pose health risks from dust and, in some cases, direct
injury by impingement on skin.
11. The evaluation of other organic solvents to
replace the halogenated solvents cannot be considered complete
unless the total health effects of the replacement are weighed
against those of the compound being replaced. Aside from the
cost comparison between the substitute solvent and the
halogenated solvent, the health risks associated with the sub-
stitutes, including flammability, toxicity, and contribution to
ambient ozone, must be evaluated. The consideration given to
CFC-11 in section 2.3.4 as a potential replacement for CFC-113
must be questioned when the sole justification for replacing
CFC-113 is its unproven hypothetical effect on stratospheric
ozone and the chlorine contribution of CFC-11 is equal to or
greater than that of CFC-113 on an equal weight basis. It
should be noted that ozone depletion estimates are theoretical
in nature and ozone depletion has not been detected by actual
measurements. Although it may be possible from an engineering
standpoint to control solvent losses of CFC-11 from degreasing
operations, it must be recognized that a solvent which
essentially boils at room temperature will be difficult to
B-9
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contain and this difficulty will be compounded in warmer
climates and high altitude locations.
12. In conclusion, it is common to find all varie-
ties of metal cleaning processes in diversified metal manufac-
turing plants. The choices of metal cleaning processes for
these plants have been made by trained engineering and purchas-
ing professionals and are based on favorable economic, energy,
safety, and performance considerations. In spite of the pre-
sent regulatory focus on halogenated solvent emissions, such
solvents continue to be widely employed due to their recognized
value. Alternatives to the halogenated solvents can be appro-
priately explored only after an evaluation of the health and
environmental risks associated with each of the suggested
alternatives. Use of any alternatives to halogenated solvents
without full appraisal of the relative risks of both systems
cannot be assumed to result in an overall reduction of risk to
workers or the public.
DRY CLEANING
The statement on page 3-1 that "Perchloroethylene is
nonflammable . . . and is comparable to petroleum solvents in
price" should be changed to "... . and is competitive with
petroleum solvents on a performance or production basis."
Although the price per kilogram for both solvents is roughly
competitive, the cost per gallon for perchloroethylene is two
times or more greater than that for petroleum solvents given on
page 3-23. B_10
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The only alternative to halogenated solvent dry
cleaning proposed in the analysis is petroleum solvent dry
cleaning. The comparison of these processes in the draft ana-
lysis illustrates the danger of failing to evaluate the total
risks associated with alternatives. One would assume from the
draft analysis that the substitution of petroleum solvent for
perchloroethylene in dry cleaning would substantially reduce
the total risk experienced both by the general public and oper-
ating personnel. This conclusion is suggested in spite of the
fact that the dry cleaning industry historically used petroleum
solvent and has been in the process of converting to perchloro-
ethylene over a period of about 50 years. That this trend con-
tinues is supported by the statement, on page 3-13, that "One
company . • • reported that an order for a petroleum washer had
not been received in two years." It is common in this industry
for one or more members of the proprietor's family to operate
the dry cleaning equipment. Therefore, it is reasonable to
expect that these proprietors have great concern for the wel-
fare of dry cleaning operators and would only convert to a
safer system from one which poses greater danger. The far
greater relative fire hazard of petroleum solvents compared to
perchloroethylene is recognized in hundreds of municipal fire
codes throughout the country.
Dry cleaning businesses tend to be located in
^
buildings with other commercial establishments or in buildings
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with apartment dwellings. In such cases, the solvent must be
transported through densely populated areas from bulk
inventories to the dry cleaner. Therefore, the fire hazard
associated with petroleum dry cleaning is not limited to the
dry cleaning business itself. The text reports 11,800 to
18,000 coin-operated dry cleaning businesses and notes that
they would be prevented from converting to petroleum solvents
by fire protection codes. Even if permissible, this conversion
would be impractical in most cases due to space considerations.
Thus, the statement on page 3-12 "When all of the above
factors are considered, petroleum solvents are shown to be a
complete substitute for perc" is certainly not true for
coin-operated dry cleaning businesses.
Similarly, the report notes that some commercial dry
cleaning businesses could not physically adapt to petroleum
solvent dry cleaning or would be prevented from doing so by
fire codes. A large portion of dry cleaning businesses lease
building space and may justifiably be reluctant to make
building improvements to meet fire codes when they do not own
the building. As stated on page 3-28, "This would leave the
proprietor with the option of finding new space or going out of
business." In the first instance, the cost of operation would
go up substantially because the proprietor would need to
maintain a store-front dry cleaning business to retain his cus-
s
tomers while relocating his dry cleaning facility in another
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acceptable location. Neither of the options stated on page
3-28 for existing perchloroethylene dry cleaners required to
convert to petroleum solvents supports the conclusion that
petroleum dry cleaning is "a complete substitute for perc."
The toxicology of perchloroethylene has been extensi-
vely tested. No summation of the toxicology of petroleum sol-
vents is presented or referenced.
The adverse health effects of ozone are the basis for
a national ambient air quality standard. In a draft report
entitled "Photochemical Reactivity of Perchloroethylene"
(October 1982), EPA concludes that perchloroethylene is less
photochemically reactive than ethane. If this conclusion is
confirmed after public review of the draft report, EPA will
have no justification for requiring regulation of perchloro-
ethylene as an ozone precursor. On the other hand, it is gen-
erally recognized that the petroleum solvents contribute to
ambient ozone. Moreover, uncontrolled emissions from petroleum
solvent dry cleaning operations are eight times those from per-
chloroethylene dry cleaning operations on a gallon basis (page
3-23).
With regard to the economic comparisons, several
observations are in order. A reasonable economic return could
have been expected on an investment of $29,000 for perchloro-
ethylene dry cleaning equipment several years ago at an
sS
interest rate of less than 10 percent per annum. However,
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retiring that perchloroethylene equipment now and reinvesting
approximately $46,000 for petroleum cleaning equipment at a
probable interest rate considerably above 10 percent is likely
to be much less attractive, particularly when combined with
increased operating costs. The cost scenarios in the draft
analysis for converting from perchloroethylene to petroleum
solvents do not examine the investments needed for rewiring,
fire walls, and boiler modifications to provide an explosion-
resistant facility. No costs are associated with fire detec-
tion or fire extinguishing equipment. Further, a scenario for
relocating the petroleum dry cleaning machinery away from pop-
ulated areas while maintaining a dry cleaning storefront in the
old location to preserve customer loyalty needs to be consid-
ered, as the failure of a large number of small businesses
would be expected in such circumstances.
There are a number of other deficiencies in the anal-
ysis of the economic effects of conversion from perchloroethy-
lene to petroleum solvent dry cleaning. It is questionable
that the useful life of petroleum solvent dry cleaning equip-
ment is thirty years unless technological advances are disre-
garded and it is assumed that plant operators, due to the lower
cost of petroleum solvents, have grown unconcerned about sol-
vent leakage and losses. Even if this equipment lifetime were,
realistic, we question whether a typical operator would accept
a return of capital over a thirty-year period. It does not
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seem probable that the maintenance costs for a petroleum
solvent dry cleaning system could remain as low as such costs
for a perchloroethylene dry cleaning system, due to the differ-
ence in the original capital costs and to the longer expected
life of the petroleum dry cleaning equipment. The overhead
costs for both types of operations are described on page 3-24
as being equal to 4 percent of the equipment costs. However,
the annual cost comparisons in tables 3-10, 3-11, and 3-12 show
the overhead to be the same for both perchloroethylene plants
and petroleum plants. This appears to be inconsistent.
Finally, it would be expected that the insurance costs for
petroleum dry cleaning would be greater because of the
increased fire hazard due to the use of flammable solvents and
the value of the equipment.
SURFACE COATINGS
Nearly all paints were once formulated with petroleum
hydrocarbon solvents. Such solvents contribute to ambient
ozone formation. As previously noted, EPA has determined that
the formation of ozone in the ambient atmosphere is adverse to
human health and has responded to this problem by limiting
emissions of anthropogenic hydrocarbon solvents. Much of the
interest in methylene chloride and methyl chloroform, which are
negligibly photochemically reactive, has been stimulated by
"regulations to control ozone precursors.
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The replacement of halogenated solvents with petro-
leum solvents in paint formulation is not necessarily a simple
matter and would not take place in an otherwise unregulated
business area. Reformulation to petroleum solvent paint sys-
tems would, in some cases, also require changes in the resins
and/or pigmentation of the paints. In turn, these changes
might require alteration or replacement of various portions of
the paint handling or application equipment. In order to
maintain compliance with ambient ozone regulations, even more
extensive compromises and changes might be required. The
unlimited emission of hydrocarbon solvents is not permissible
under today's ozone regulations. Therefore, the installation
of incineration equipment with or without heat recovery may be
required. Carbon adsorption could also be regarded as an
alternative in controlling the hydrocarbon solvent losses to
the atmosphere. Both of these emission control devices are
unreasonably expensive for many kinds of painting operations.
Overall operating costs would most frequently be higher where
the halogenated solvents were replaced by petroleum solvents.
Moreover, it is unlikely that the use of certain petroleum sol-
vents, such as acetone, would reduce the cost of paint per gal-
lon. In other instances, where cheaper solvents were employed,
the cost per gallon might not be reduced due to changes in the
resin or pigmentation needed to obtain parallel performance
properties.
B-16
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Many potential solvent substitutes are more toxic
than methylene chloride and 1,1,1-trichloroethane.
Essentially, all of the alternative solvents would pose greatly
increased fire risks. In the discussion of possible substi-
tutes for halogenated solvents in coatings, no data are presen-
ted which would indicate that the alternatives are as safe from
a fire hazard standpoint or pose less acute or chronic toxic
hazard to workers or the general public. While it might be
concluded that petroleum-based paints can be formulated to pro-
vide roughly equivalent gloss, adhesion, rheology, drying char-
acteristics, weatherability, etc., as those formulated with
halogenated solvents, it must be questioned whether these prop-
erties can be obtained simultaneously in existing equipment
without increased costs and without greater fire or envi-
ronmental risk or endangerment to public health.
In addition to the above properties, halogenated sol-
vents offer formability, chip resistance, rapid color change,
cold temperature stability, air drying capability, nonflammabi-
lity, and the use of standard paint application equipment, com-
bined with nil contribution to ambient ozone. All of these
properties cannot be achieved in formulations using petroleum
solvents.
It is unlikely that halogenated solvents will ever
attain a major share of the coatings marketplace currently held
by petroleum solvent-based paints. Most of the petroleum-base
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coating applications will convert to waterborne, powder, or 100
percent solid systems where possible. However, these new
painting technologies cannot satisfy all of the coatings
requirements. Estimates of the potential use of methylene
chloride or 1,1,1-trichloroethane as future potential
replacements for petroleum hydrocarbons have ranged from 5 to
10 percent. These solvents are used as a primary carrier with-
out loss of application or coating performance characteristics.
The technology exists to prevent substantial losses of solvent
during application. As industry use of these solvents becomes
more sophisticated, air drying operations, ovens with reduced
ventilation rates and/or other solvent recovery techniques
offer a considerable reduction in energy requirements.
Foremost among the attributes of methylene chloride
and 1,1,1-trichloroethane in coatings operations are the redu-
ced fire hazard and compliance with ozone regulations without
exceedingly high capital and operating costs. The draft anal-
ysis contains no comparison of the total environmental and
health risks of solvent alternatives for paint formulation with
the two halogenated solvent systems. We are confident that
when the human health and environmental risks and benefits of
methylene chloride and 1,1,1-trichloroethane are weighed
against those of feasible alternatives, the advantages of these
halogenated solvents will be obvious.
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FABRIC SCOURING
Textile processes such as dyeing, finishing, and
scouring have been dominated by aqueous processes over the
years. Historically, solvent processes in the textile industry
have represented a small minority of operations and have been
used in place of the customary aqueous processes. Certainly,
if this report had been written from the viewpoint of prevent-
ing water pollution, solvent scouring would have been one of
the proposed substitutes. From an energy standpoint, solvent
scouring is many times more efficient when the fabric must be
dried. Assuming an equal weight of water and perchloroethylene
are left on fabric, the water will require 10.8 times more
energy for drying than the perchloroethylene. If equal volumes
of water and perchloroethylene are left on fabric, 6.66 times
more energy is required for the water. Since the industry has
an obvious preference for aqueous processes, it is fair to
assume that solvent processes are selected only after careful
consideration. However, the draft analysis does not examine
the special performance characteristics, costs, space consider-
ations, energy limitations, and other factors which are impor-
tant considerations in choosing a solvent scouring process.
CONCLUSION
The analysis of alternatives cannot be complete with-
-out i) an analysis of the human health and environmental risks
associated with halogenated solvent usage; and ii) an analysis
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of the human health and environmental risks associated with the
use of alternatives. The former is under way and will probably
be completed in 1983. The present document should be revised
to incorporate the latter so that a comparison of risks may be
made if it should be determined that present or expected envi-
ronmental concentrations of the halogenated cleaning solvents
pose any significant risk to human health or the environment.
Should a comparison of relative risks favor the use
of an alternative to a halogenated cleaning solvent in any par-
ticular operation or process, the relative performances and
overall cost of replacement, including capital investment
needed, energy usage, water pollution, operating costs, and
other factors, should be weighed against the expected benefits
or reductions in risk.
Respectfully submitted,
HALOGENATED CLEANING SOLVENTS ASSOCIATION
Alan W. Rautio
Executive Director
Attachments
cc: Mr. Richard M. Rehm
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