Sr EPA
United States Control Technology EPA-450/3-88-009
Environmental Protection Center October 1988
Agency Research Triangle Park NC 27711
Reduction of
Volatile Organic Compound
Emissions from
Automobile Refinishing
control f technology center
-------
EPA-450/3-88-009
REDUCTION OF VOLATILE ORGANIC COMPOUND EMISSIONS
FROM AUTOMOBILE REFINISHING
CONTROL TECHNOLOGY CENTER
SPONSORED BY:
Emission Standards Division
Office of Air Quality Planning and Standards
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
Air and Energy Engineering Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Research Triangle Park.NC 27711
Center for Environmental Research Information
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, OH 45268
October 1988
-------
EPA-450/3-88-009
October 1988
REDUCTION OF VOLATILE ORGANIC COMPOUND EMISSIONS
FROM AUTOMOBILE REFINISHING
Prepared by:
Carol Athey
Charles Hester
Mark McLaughlin
Roy M. Neulicht
Mark B.Tumer
MIDWEST RESEARCH INSTITUTE
Gary, North Carolina 27513
EPA Contract No. 68-02-4379
ESD Project No. 87/30
MRI Project No. 8950-08
Prepared for:
Robert J. Blaszczak
Office of Air Quality Planning and Standards
Control Technology Center
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
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PREFACE
The Automobile Refinlshing investigation was funded as a project of
EPA's Control Technology Center (CTC).
The CTC was established by EPA's Office of Research and Development
(ORD) and Office of Air Quality Planning and Standards (OAQPS) to provide
technical assistance to State and local air pollution control agencies.
Three levels of assistance can be accessed through the CTC. First, a CTC
HOTLINE has been established to provide telephone assistance on matters
relating to air pollution control technology. Second, more in-depth engi-
neering assistance can be provided when appropriate. Third, the CTC can
provide technical guidance through publication of technical guidance docu-
ments, development of personal computer software, and presentation of
workshops on control technology matters.
The technical guidance projects, such as this one, focus on topics of
national or regional interest that are identified through State and Local
agencies. This guidance provides technical information that agencies can
use to develop strategies for reducing VOC emissions from automobile
refinishing operations. It is of particular interest to those agencies
that are seeking additional VOC emission reductions in ozone nonattainment
areas. These areas tend to have a high population density and, therefore, a
high frequency of automobile repair and repainting.
This report provides information on the coating application process,
VOC emissions and emissions reductions, and costs associated with the use
of alternative coating formulations and equipment used in the automobile
refinishing industry. This information will allow planners to: 1) identify
available alternative technologies for reducing VOC emissions from automobile
refinishing operations; 2) determine VOC emissions and achievable VOC
emission reductions; and 3) evaluate the cost and environmental impacts
associated with implementing these alternatives.
ii
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ACKNOWLEDGEMENT
This report was prepared by staff in Midwest Research Instititute1s
Environmental Engineering Department located in Gary, North Carolina.
Participating on the project team for the EPA were Robert Blaszczak of the
Office of Air Quality Planning and Standards and Charles Darvin of the
Air and Energy Engineering Research Laboratory. The data presented were
generated through a literature search and surveys of paint formulators,
equipment manufacturers, and industry trade organizations.
iii
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TABLE OF CONTENTS
Page
LIST OF TABLES v
SECTION 1.0 INTRODUCTION 1-1
SECTION 2.0 SUMMARY 2-1
SECTION 3.0 AUTOMOBILE REFINISHING SOURCE CHARACTERIZATION AND
PROCESS DESCRIPTION 3-1
3.1 SOURCE CHARACTERIZATION 3-1
3.2 PROCESS DESCRIPTION 3-1
3.2.1 Vehicle Preparation 3-2
3.2.2 Primers 3-2
3.2.3 Topcoats 3-5
3.2.4 Application Techniques 3-8
3.2.5 Equipment Cleanup 3-10
3.3 REFERENCES FOR SECTION 3 3-10
SECTION 4.0 EMISSION ESTIMATES 4-1
4.1 BACKGROUND 4-1
4.2 BASELINE VOC EMISSIONS 4-5
4.3 CALCULATIONS 4-5
4.4 REFERENCES FOR SECTION 4 4-7
SECTION 5.0 EMISSION REDUCTION TECHNIQUES 5-1
5.1 ALTERNATIVES FOR REDUCING VOC EMISSIONS
DURING VEHICLE PREPARATION 5-1
5.1.1 Reduced-VOC Cleaners 5-1
5.1.2 Detergents 5-2
5.2 ALTERNATIVES FOR REDUCING VOC EMISSIONS
DURING PRIMER APPLICATION 5-2
5.2.1 Improved Transfer Efficiency 5-2
5.2.2 Waterborne Primers.* 5-4
5.2.3 Urethane Primers 5-5
5.3 ALTERNATIVES FOR REDUCING VOC EMISSIONS
DURING TOPCOAT APPLICATION 5-5
5.3.1 Improved Transfer Efficiency 5-5
5.3.2 Reduced-VOC Coatings 5-7
5.4 ALTERNATIVES FOR REDUCING VOC EMISSIONS
DURING EQUIPMENT CLEANUP 5-8
5.5 ALTERNATIVES FOR SHOP ADD-ON CONTROL OF VOC
EMISSIONS 5-9
• 5.6 REFERENCES FOR SECTION 5 5-10
1v
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TABLE OF CONTENTS (continued)
SECTION 6.0 ENVIRONMENTAL ANALYSIS 6-1
6.1 AIR POLLUTION 6-1
6.2 OTHER CONSIDERATIONS 6-1
6.2.1 Water Pollution 6-1
6.2.2 Solid Waste Disposal 6-3
6.2.3 Energy 6-3
6.3 REFERENCES FOR SECTION 6 6-3
SECTION 7.0 CONTROL COST ANALYSIS 7-1
7.1 BASIS FOR CAPITAL COSTS 7-1
7.2 BASIS FOR ANNUALIZED COSTS 7-3
7.2.1 Annualized Raw Material Costs 7-3
7.2.2 Annualized Equipment Costs 7-5
7.2.3 Annual1zed Operating Costs for Add-On
Contro Is 7-6
7.3 EMISSION REDUCTION COSTS AND EFFECTIVENESS 7-6
7.4 REFERENCES FOR SECTION 7 7-12
SECTION 8.0 EXISTING REGULATIONS 8-1
8.1 INTRODUCTION 8-1
8.2 FEDERAL REGULATIONS 8-1
8.3 STATE AND LOCAL REGULATIONS 8-1
8.3.1 New York 8-2
8.3.2 Texas 8-2
8.3.3 Oregon 8-2
8.3.4 New Jersey 8-2
8.3.5 California 8-2
8.4 AGENCIES CONTACTED 8-3
8.5 REFERENCES FOR SECTION 8 8-3
SECTION 9.0 COMPLIANCE EVALUATION CONSIDERATIONS 9-1
SECTION 10.0 GLOSSARY OF COATING TERMS 10-1
REFERENCES FOR SECTION 10 10-6
APPENDIX A. METHODOLOGY FOR DETERMINING AUTOMOBILE REFINISHING
SHOP SIZE CATEGORIES, THE NUMBER OF AUTOMOBILE
REFINISHING JOBS PER SHOP, AND THE TYPES AND
AMOUNTS OF COATINGS USED IN EACH SHOP A-l
APPENDIX B. TYPICAL COATING PARAMETERS FOR VOC CALCULATIONS
• (CALCULATIONS FOR TABLE 4-2) B-l
REFERENCES FOR APPENDIX B B-4
APPENDIX C. CALCULATION OF THERMAL INCINERATION ADD-ON CONTROL
COSTS C-l
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LIST OF TABLES
Page
TABLE 2-1. VOC EMISSION REDUCTION TECHNIQUES CURRENTLY AVAILABLE
IN THE AUTOMOBILE REFINISHING INDUSTRY 2-2
TABLE 2-2. VOC EMISSIONS, EMISSION REDUCTIONS, AND TOTAL ANNUALIZED
COSTS FOR ALTERNATIVE EMISSION REDUCTION TECHNIQUES
APPLIED TO A SMALL FACILITY 2-3
TABLE 2-3. VOC EMISSIONS, EMISSION REDUCTIONS, AND TOTAL ANNUALIZED
COSTS FOR ALTERNATIVE EMISSION REDUCTION TECHNIQUES
APPLIED TO A MEDIUM FACILITY 2-4
TABLE 2-4. VOC EMISSIONS, EMISSION REDUCTIONS, AND TOTAL ANNUALIZED
COSTS FOR ALTERNATIVE EMISSION REDUCTION TECHNIQUES
APPLIED TO A VOLUME FACILITY 2-5
TABLE 2-5. MATRIX OF VOC EMISSION REDUCTION ALTERNATIVES FOR A
SMALL AUTOMOBILE REFINISHING SHOP AND ESTIMATED
EMISSION REDUCTIONS 2-8
TABLE 2-6. MATRIX OF VOC EMISSION REDUCTION ALTERNATIVES FOR A
MEDIUM AUTOMOBILE REFINISHING SHOP AND ESTIMATED
EMISSION REDUCTIONS 2-9
TABLE 2-7. MATRIX OF VOC EMISSION REDUCTION ALTERNATIVES FOR A
VOLUME AUTOMOBILE REFINISHING SHOP AND ESTIMATED
EMISSION REDUCTIONS 2-10
TABLE 3-1. TYPICAL PRIMER PARAMETERS 3-3
TABLE 3-2. TYPICAL TOPCOAT PARAMETERS 3-7
TABLE 4-1. VOC EMISSION SOURCES 4-2
TABLE 4-2. TYPICAL COATING PARAMETERS FOR VOC CALCULATIONS 4-3
TABLE 4-3. TYPICAL AUTOMOBILE REFINISHING PAINT USAGE AND EQUIPMENT
BY FACILITY TYPE 4-4
TABLE 4-4. BASELINE VOC EMISSIONS FROM AUTOMOBILE REFINISHING BY
FACILITY TYPE 4-6
TABLE 6-1. COMPARISON OF VOC EMISSIONS FROM AVAILABLE REDUCTION
TECHNIQUES 6-2
TABLE 7-1. CAPITAL EQUIPMENT COST, IN $ 7-2
vi
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LIST OF TABLES (continued)
Page
TABLE 7-2. TYPICAL COATING COSTS, $ PER GALLON 7-4
TABLE 7-3. COST OF AVAILABLE TECHNIQUES FOR REDUCING VOLATILE
ORGANIC COMPOUND EMISSIONS FROM A SMALL AUTOMOBILE
REFINISHING FACILITY 7-7
TABLE 7-4. COST OF AVAILABLE TECHNIQUES FOR REDUCING VOLATILE
ORGANIC COMPOUND EMISSIONS FROM A MEDIUM AUTOMOBILE
REFINISHING FACILITY 7-8
TABLE 7-5. COST OF AVAILABLE TECHNIQUES FOR REDUCING VOLATILE
ORGANIC COMPOUND EMISSIONS FROM A VOLUME AUTOMOBILE
REFINISHING FACILITY 7-9
TABLE 9-1. APPLICABILITY OF COMPLIANCE EVALUATION TECHNIQUES 9-2
TABLE C-l. THERMAL INCINERATION COSTS C-2
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1.0 INTRODUCTION
The Clean Air Act Identified December 31, 1987, as the final date to
attain the national ambient air quality standard (NAAQS) for ozone.
Congress recently extended the compliance deadline to August 31, 1988. As
of this writing, 345 counties including 68 cities are still in nonattain-
ment of the ozone NAAQS. On May 26, 1988, the U. S. Environmental Protec-
tion Agency (EPA) mailed letters to 44 States and the District of Columbia
that have ozone nonattainment areas stating that current State implementa-
tion plans (SIP's) to control ozone are inadequate and that a new round of
planning is needed. (Bureau of National Affairs, Environment Reporter,
May 6, 1988, p. 3 and June 3, 1988, p. 171).
Under the proposed ozone policy published in the Federal Register on
November 24, 1987 (52 FR 45044), emissions of volatile organic compounds
(VOC's) must be reduced to a level consistent with attaining the ozone
NAAQS as demonstrated by atmospheric dispersion modeling. Once the State
has determined the VOC emission reduction required to meet the NAAQS, it
must identify and select control measures that will produce the required
reductions as expeditiously as practicable.
Nonattainment areas are likely to be those with a high population
density and, therefore, a high frequency of automobile repair and
repainting. This report provides technical information that State and
local agencies can use to develop strategies for reducing VOC emissions
from automobile refinishing operations. The information in this document
will allow planners to: (1) identify available alternative technologies
4 for reducing VOC emissions from automobile refinishing operations;
(2) determine VOC emissions and achievable VOC emission reductions; and
(3) evaluate the cost and environmental impacts associated with imple-
menting these alternatives.
This document provides information on the application processes, VOC
emissions and emissions reductions, and costs associated with the use of
alternative coating formulations and equipment used in the motor vehicle
refinishing industry. This information was generated through a literature
search, site visits, and surveys of equipment manufacturers, coating
formulators, and industry trade associations. Section 2.0 presents a
1-1
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summary of the findings of this study. Section 3.0 provides a source
characterization and description of the processes used to refinish
automobiles. Section 4.0 provides VOC emission estimates for each of the
automobile refinishing process steps and for typical facilities.
Section 5.0 discusses each VOC emission reduction alternative in detail,
including advantages and disadvantages. Section 6.0 provides emission
estimates for each alternative and estimated emission reductions from
current operating practice. Section 6.0 also describes the environmental
impacts associated with the implementation of each alternative. Section 7.0
presents a cost analysis that includes a methodology for computing annual-
ized equipment and material cost and anticipated incremental cost (savings)
from baseline for each alternative. This discussion will assist the users
of this document in developing the cost information necessary to develop a
VOC reduction strategy specific to their area. Section 8.0 discusses
existing Federal and State regulations that apply to this industry.
Section 9.0 discusses factors to consider with regard to determining
compliance with regulations that might be proposed for the automobile
reflnishing industry, and Section 10.0 presents a glossary of coating
terminology.
1-2
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2.0 SUMMARY
The purpose of this document is to provide technical information that
State and local agencies can use to develop strategies for reducing VOC
emissions from automobile refinishing operations. This section presents
the findings of this study including alternative VOC reduction techniques,
potential VOC emission reductions, and costs of implementing the
alternatives.
Automobile refinishing operations can be categorized into four
process steps. These steps are vehicle preparation, primer application,
topcoat application, and spray equipment cleanup. Emissions of VOC's are
the result of organic solvent evaporation during vehicle preparation and
equipment cleanup and during and shortly after the application of primers
and topcoats. Currently, there are several available VOC emission
reduction techniques that are applicable to these four steps. These
techniques are listed in Table 2-1.
To characterize the automobile refinishing industry and to take into
account the large diversity in shop size, the estimated 83,000. shops were
divided into the following three categories: (1) small shops with annual
sales up to $150,000 that perform 6 partial vehicle jobs per week,
(2) medium shops with annual sales between $150,000 and $750,000 that
perform 13 partial and 1 complete vehicle jobs per week, and (3) volume
shops with annual sales of greater than $750,000 that perform 14 partial
and 15 complete vehicle jobs per week. Emission reduction techniques that
were selected for evaluation include the use of alternative coatings,
spray equipment with improved transfer efficiency, the installation of
solvent recovery spray equipment cleaning systems and, for volume shops
only, add-on control. In order to estimate VOC emissions, VOC emission
reductions, and costs of emission reductions, assumptions were made on the
types of coatings used and equipment available for each facility type.
Tables 2-2, 2-3, and 2-4 summarize the emission and cost data for the
baseline condition and alternative controls for typical small, medium, and
volume shops, respectively. These tables present the alternative emission
reduction techniques, estimated VOC emissions, VOC emission reductions
from baseline, the total annualized cost of the alternatives, and the cost
2-1
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TABLE 2-1. VOC EMISSION REDUCTION TECHNIQUES CURRENTLY AVAILABLE
IN THE AUTOMOBILE REFINISHING INDUSTRY
Vehicle
preparation
Reduced-VOC
cleaners
Detergents
Priner application
Enaael primers
Waterborne primers
Uretnane primers
Topcoat application
Higher solids coatings
(available for basecoats
and clearcoats)
Electrostatic spray
Equipment cleanup
Cleanup solvent
recovery systems
equ i pment
Electrostatic spray
equipment High-volume, low-pressure
spray equipment
HIgh-voIume, Iow-pressure
spray equipment Add-on control
Add-on control
2-2
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TABLE 2-2. VOC EMISSIONS, EMISSION REDUCTIONS, AND TOTAL ANNUALIZED
COSTS FOR ALTERNATIVE EMISSION REDUCTION TECHNIQUES
APPLIED TO A SMALL FACILITY4
Emission reduction technique
VOC
emissions,
tons/yr
VOC reduction
from base Iine
tons/yr
Percent
Total
annual Ired
cost, $/yr
aeryIic enamels
Replace lacquers and enamels 0.59
with urethanes0
Replace solvent-borne primers 0.96
with waterborne primers
Replace conventional clear- 0.95
coats with higher solids
clears
Install cleanup solvent 1.08
recovery systems
Replace conventional air 0.86
atomizing spray guns with
high-volume, low-
pressure (HVLP) spray
equ i pment
0.68
0.31
0.32
0.19
0.41
54
24
25
15
32
8,600
7,100
8,600
7,000
6,100
Cost
(savings)
compared to
base Iine,
S/yr
Current practice (baseline)
Replace lacquers with
1.27
0.69
NA
0.58
NA
46
7,400
6,200
NA
( 1 ,200)
1,200
(300)
1,200
(400)
(1,300)
MA » not appl i cable.
"The assumptions for the small facility include: (1) lacquers are primarily used; (2) no
spray booth; and (3) six partial jobs (10 square feet per partial job) are completed per
option involves replacing lacquer primers and topcoats with acrylic enamel primers and
topcoats .
This option involves replacing lacquer and enamel primers and topcoats with urethane primers
and topcoats.
2-3
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TABLE 2-3. VOC EMISSIONS, EMISSION REDUCTIONS, AND TOTAL ANNUALIZED
COSTS FOR ALTERNATIVE EMISSION REDUCTION TECHNIQUES
APPLIED TO A MEDIUM FACILITY*
Emission reduction technique
VOC
emissions,
tons/yr
VOC reduction
from baseIine
tons/yr
Percent
Total
annual(zed
cost, $/yr
aery Iic enamels
Replace lacquers and an
with urethanesc
Replace solvent-borne primers
with waterborne prii
Replace conventional clear-
coats w i th h!gher soIi ds
clears
Install cleanup solvent recovery
syste
Replace conventional air
atomizing spray guns with
high-volume, low-
pressure (HVLP) spray
equipment
1.89
2.73
2.82
3.08
2.46
1.73
0.90
0.81
0.55
1.17
48
25
22
15
32
32,800
29,600
30,400
28,900
23,300
Cost
(savings)
compared to
base Iine,
S/yr
Current practice (baseline)
Replace lacquers with
3.63
2.27
NA
1.36
NA
37
30,100
23,600
NA
(6,500)
2,700
(500)
300
(1,200)
(6,800)
NA * not applicable.
^The assumptions for the medium facility include: (1) enamels are primarily used, but some
lacquers are used; (2) the shop has one spray booth; and (3) 13 partial jobs (10 square feet
per partial job) and 1 entire vehicle job (100 square feet per entire vehicle job) are
.completed per week.
nThis option involves replacing lacquer primers and topcoats with acrylic enamel primers and
topcoats.
This option involves replacing lacquer and enamel primers and topcoats with urethane primers
and topcoats.
2-4
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TABLE 2-4. VOC EMISSIONS, EMISSION REDUCTIONS, AND TOTAL ANNUALIZED
COSTS FOR ALTERNATIVE EMISSION REDUCTION TECHNIQUES
APPLIED TO A VOLUME FACILITY3
Emission reduction technique
Current pract i ce ( base line)
Replace enamels with urethanes
Replace solvent-borne primers
VOC
emissions,
tons/yr
11.1
9.1
8.1
VOC reduction
from basel !ne
tons/yr Percent
NA NA
2.0 18
3.0 27
Total
annual ized
cost , S/yr
127,600
177,300
126,300
Cost
(savings)
compared to
basel ine,
S/yr
NA
49,700
(1,300)
with waterborne primers
Replace conventional clear- 10.4
coats with higher solids
cI ears
Install cleanup solvent recovery 10.4
Replace conventional air atomizing 6.0
spray guns with high-volume,
low-pressure (HVLP) spray
equ i pment
0.7
1.6
5.1
15
46
143,000
123,900
81,400
Add-on control:
Thermal incineration
3.5
7.6
68 452,000
15,400
(3,700)
(45,700)
363,000
NA * not applicable.
*The assumptions for the volume shop include: (1) only- enamels and urethanes are used;
(2) the shop has two spray booths; and (3) 14 partial jobs (10 square feet per partial job)
.and 15 entire vehicle jobs (100 square feet per entire vehicle job) are completed per week.
^Tiis option involves replacing enamel primers and topcoats with urethane primers and
topcoats.
2-5
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(savings) for Implementation of the alternative controls compared to
baseline.
The results of the study Indicate that several control options result
in no additional cost to implement, and in fact result in a cost
savings. For the small, medium, and volume facilities, significant VOC
reductions (30 to 45 percent) can be achieved by replacing conventional
air-atomizing spray guns with high-volume, low-pressure (HVLP) spray
equipment. A cost savings is expected from this control technique because
the higher transfer efficiency (about 65 percent vs. about 35 percent for
conventional air-atomizing spray guns) results in less paint usage, when
HVLP spray equipment is used in conjunction with a paint mixing station.
Experience with use of the HVLP spray equipment within the industry is
limited. Some problems with color matching topcoats have been reported.
However, some users are reporting acceptable color matching results and
have indicated that experience with the equipment is a necessary factor in
achieving good results. For all facilities, significant VOC emission
reductions (about 15 percent) can be achieved by using a cleanup solvent
recovery system. This control technique also results in a savings because
solvent usage 1s reduced. The remaining alternative controls involving
switching from conventional coatings to lower VOC coatings (e.g.,
urethanes) and, with a few exceptions, involve some additional cost. One
exception is for small facilities, where switching from lacquers to
acrylic enamels 1s expected to result in a 45 percent emission reduction,
as well as a cost savings. The cost savings is a result of the lower cost
of materials which offsets the capital cost (annualized over 10 years) for
Installing a spray booth to accomodate the additional drying time required
for enamel coatings. Also, for all types of facilities, switching from
conventional primers to waterborne primers is expected to result in a VOC
emission reduction (approximately 20 percent) at no additional cost.
Add-on controls for spray booth emissions from large facilities were
briefly investigated. Add-on controls are expected to control emissions
effectively (greater than 60 percent reduction) but have a very high cost
associated with their Installation and operation.
Note that 1f multiple alternatives are implemented, the emission
reduction achieved will not necessarily be the sum of the individual
2-6
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emission reductions presented in Tables 2-2, 2-3, and 2-4. Since all the
emission reductions are calculated from the baseline condition, after one
alternative has been implemented, subsequent implementation of other
alternatives will have a different effect from that presented in the
tables. Nonetheless, implementation of multiple alternatives will have a
positive impact on VOC emission reduction. For each type of facility,
several of the control alternatives can be implemented at no additional
cost. Tables 2-5, 2-6, and 2-7 present matrices of emission reduction
alternatives and estimated VOC emission reductions for small, medium, and
volume automobile refinishing shops, respectively. The emission reduc-
tions attributed to add-on controls applied to the volume shop were not
included in Table 2-7. These tables present the same coating alternatives
described in Tables 2-2, 2-3, and 2-4. Additionally, Tables 2-5, 2-6, and
2-7 show the VOC emission reductions that may be achieved if a combination
of both a coating change and an equipment change is implemented. While
these tables are helpful in determining the potential total reductions
achievable using multiple options, it should be noted that the reductions
are from assumed baselines. Therefore, if the baseline for a particular
automobile refinishing shop is different from that developed in this
study, then the reduction for a particular alternative or multiple alter-
natives will likewise be different.
2-7
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TABLE 2-5. MATRIX OF VOC EMISSION REDUCTION ALTERNATIVES FOR A SMALL
AUTOMOBILE REFINISHING SHOP AND ESTIMATED EMISSION REDUCTIONS
VOC
reduction
Coating alternatives
Exclusive use of lacquers
(current practice)
Basel ine
Alternative 1
Alternative 2
Alternative 3
Replace lacquer primers with
waterborne • pr i mers
Alternative 4
Alternative 5
Alternative 6
Alternative 7
Replace lacquer clearcoats with
h i gher so 1 i ds c 1 ear coats
Alternative 8
Alternative 9
Alternative 10
Alternative 11
Replace lacquers with enamels
Alternative 12
Alternative 13
Alternative 14
Alternative 15
Replace lacquers with urethanes
Alternative 16
Alternative 17
Alternative 18
Alternative 19
Solvent
recovery
res
X
X
X
X
X
X
X
X
X
X
emission
alternatives
Transfer
effi-
ciency,
percent
No 35 55
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
•
X
X
X
X
Emissions,
tons/yr
1.27
1.08
0.86
0.67
0.96
0.83
0.65
0.51
0.95
0.76
0.69
0.50
0.69
0.50
0.55
0.36
0.59
0.40
0.49
0.30
Emission
lons/yr
NA
0.19
0.41
0.60
0.31
0.45
0.62
0.76
0.32
0.51
0.58
0.78
0.58
0.77
0.72
0.91
0.68
0.87
0.78
0.97
reduction
Percent
NA
15
32
47
24
35
49
60
25
40
46
61
46
61
57
72
54
69
61
76
2-8
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TABLE 2-6. MATRIX OF VOC EMISSION REDUCTION ALTERNATIVES FOR A MEDIUM
AUTOMOBILE REFINISHING SHOP AND ESTIMATED EMISSION REDUCTIONS
VOC
reduction
So 1 vent
recovery
Coating alternatives
Use of lacquers and enamels
(current practice)
Basel ine
Alternative 1
Alternative 2
Alternative 3
Replace lacquer and enamel primers
with waterborne primers
Alternative 4
Alternative 5
Alternative 6
Alternative 7
Replace lacquer and enamel clears
with higher solids clears
Alternative 8
Alternative 9
Alternative 10
Alternative 11
Replace lacquers with enamels
Alternative 12
Alternative 13
Alternative 14
Alternative 15
Replace lacquers and enamels
with urethanes
Alternative 16
Alternative 17
Alternative 18
Alternative 19
res
X
X
X
X
X
X
X
X
X
X
emission
a 1 ternat i ves
iranster
effi-
ciency,
percent
No 35 65
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Emissions,
tons/yr
3.63
3.08
2.46
1.91
2.73
2.34
1.83
1.44
2.82
2.28
2.02
1.48
2.27
1.73
1.55
1.00
1.89
1.35
1.52
0.98
Em i ss i on
lons/yr
NA
0.54
1.17
1.72
0.90
1.28
1.80
2.19
0.81
1.35
1.61
2.15
1.36
1.90
2.08
2.63
1.73
2.28
2.11
2.65
reduction
Percent
NA
15
32
47
25
35
50
60
22
37
44
59
37
52
57
72
48
63
58
73
2-9
-------
TABLE 2-7. MATRIX OF VOC EMISSION REDUCTION ALTERNATIVES FOR A VOLUME
AUTOMOBILE REFINISHING SHOP AND ESTIMATED EMISSION REDUCTIONS
Coating alternatives
VOC emission
reduction alternatives
Transfer
effi-
Solvent ciency,
recovery percent
Yes Ho 35 55
Emissions,
tons/yr
Emission reduction
rons/yr
Fercent
Use of enamels and urethanes
(current practice)
Baseline XX 11.12 NA NA
Alternative 1 X X 9.45 1.67 15
Alternative 2 XX 7.53 3.59 32
Alternative 3 XX 5.86 5.26 47
Replace enamel and urethane
primers with wateroorne primers
Alternative 4 XX 8.14 2.98 27
Alternative 5 XX 7.08 4.04 36
Alternative 6 XX 5.35 5.77 52
Alternative 7 XX 4.30 6.82 61
Replace enamel clears with
higher solids clears
Alternative 8 XX 10.39 0.74 7
Alternative 9 XX 8.72 2.40 22
Alternative 10 X X 7.13 3.99 36
Alternative 11 X X 5.46 5.66 51
Replace lacquers with enamels9
Alternative 12
Alternative 13
Alternative 14
Alternative 15
Replace enamels with urethanes
Alternative
Alternative
Alternative
Alternative
16
17
18
19
X
X
X
X
X
X
X
X
9
7
6
4
.08
.41
.43
.76
2,
3.
4.
6.
.04
.71
.69
.36
18
33
42
57
aSince the volume shops were assumed not to use lacquers at all, this category of coating
alternative does not apply to volume shops.
2-10
-------
3.0 AUTOMOBILE REFINISHING SOURCE CHARACTERIZATION AND PROCESS DESCRIPTION
The purpose of this section 1s to present an Industry profile and to
describe the process steps Involved in automobile refinishing. This
information will allow agencies to characterize shops in their area and to
identify the process steps where VOC emissions occur. Section 3.1
provides information on the estimated number of automobile refinishing
shops nationwide and categorizes these shops based on annual sales
volume. Section 3.2 describes the process steps and materials involved in
refinishing an automobile from beginning to end including vehicle prepara-
tion, coating application, descriptions of primers and topcoats, and
equipment cleanup.
3.1 SOURCE CHARACTERIZATION
Approximately 66,000 auto body shops are operating in the United
States, of which 2 percent are franchises and the remainder are classified
as independents. » In addition, an estimated 68 percent of the nation's
automobile dealerships (approximately 17,000 shops) have body shop
operations. These 83,000 body shops range in size from small shops
having less than 5 employees and sales volume under $150,000 (40 percent)
to volume shops with over 10 employees conducting $750,000 or more in
sales (10 percent). Combined, these shops perform over $10 billion in
sales annually. The typical refinishing shop employs 6 persons, conducts
$400,000 worth of business annually, and performs an average of 13 jobs
per week. For a typical shop, approximately 90 percent of the work
consists of spot and panel repainting. The entire vehicle is completely
reflnlshed only about 10 percent of the time. These percentages are
reversed for the franchise operations, which typically specialize in
repainting entire vehicles.
3.2 PROCESS DESCRIPTION
Typically, automobile refinishing is performed in conjunction with
other body repair necessitated by a collision involving the vehicle. Most
refinishing jobs involve the repair and repainting of a small portion of
the vehicle (a panel, or a "spot" on a panel). A minority of jobs involve
the overall repainting of vehicles, which is generally performed in
instances of coating failure.
3-1
-------
Definite steps must be followed when reflnishing a vehicle, whether
the job is a spot, panel, or overall repair. The surface of the vehicle
must be thoroughly cleaned to ensure proper adhesion of the coating, the
metal surface must be primed, a topcoat (either a color coat or a two-
stage basecoat and clearcoat) must be applied, and the spraying equipment
must be cleaned with solvent. Emissions of VOC's from automobile
reflnishing operations are the result of organic solvent evaporation
during vehicle preparation, during the application and drying of primers
and topcoats, and during spraying equipment cleanup.
3.2.1 Vehicle Preparation
Vehicle preparation, the first step in reflnishing an automobile, is
generally performed 1n two stages. First, the surface to be reflnished is
washed thoroughly with detergent and water to remove dirt and water
soluble contaminants and is allowed to dry. Then the surface is cleaned
with solvent to remove wax, grease, and other contaminants. This step is
important to ensure proper adhesion of the primer and topcoats. The
solvent typically used is 100 percent VOC's and 1s usually a blend of
toluene, xylene, and various petroleum distillates. Solvent cleaning of
vehicles currently accounts for approximately 8 percent of the total VOC
emissions generated by automobile refinishing. * The area to be
repainted is then sanded or chemically treated to remove the old finish
and 1s given a final solvent wipe.
3.2.2 Primers
After the surface of the vehicle has been thoroughly prepared, the
next step is the application of primer. Approximately 13 million gallons
of primer are sold each year to the automotive reflnishing Industry in the
United States.7 Primers provide corrosion resistance, fill in surface
Imperfections, and provide a bond for the topcoat. A breakdown of the
relative properties and costs for the different types of primer formula-
tions is presented in Table 3-1. The values presented for each primer
type in Table 3-1 are average values for each parameter based on a review
of industry surveys and are not intended to represent a particular
primer. These primers fall Into four basic categories: prepcoats,
primer-surfacers, primer-sealers, and sealers.
3-2
-------
TABLE 3-1. TYPICAL PRIMER PARAMETERSa
Solids content .
As sold, wt.ST
As sprayed, wt.%c
Sol Ids content .
As sold, vol.ST
As sprayed, vol. %
VOC content .
As sold, Ib/gal coating0
As sprayed, Ib/gal coating5
As sprayed, Ib/gal solids
Density, Ib/gal
Coating as sold6
Coating as sprayed0
Density of solids
Reduction ratiob f
Dry film thickness, mils9
Lacquer
46
21
33
13
4.6
6.0
45.4
8.4
7.5
14.5
1:1.5
2.0
Enamel
65
50
36
24
4.1
5.1
21.0
11.8
10.2
—
1:0.5
2.0
Waterborne
45
45
33
33
2.5
2.5
7.6
9.6
9.6
17.5
None
2.0
Urethane
57
49
37
30
3.6
4.3
14.4
10.4
9.7
—
1:0.25
2.0
Volume/vehicle .
As sprayed, gal" 2.7 1.5 1.1 1.2
Cost
As sold, $/gale . 27 31 38 53
As sprayed, $/galc 16 23 38 44
Per vehicle, $n 42 35 42 53
aThe values presented in this table are average values for the parameters
listed. The parameters for each primer type are not intended to
.represent a particular primer.
"References 1 and 9.
Calculated values based on recommended reduction ratio and 6.95 Ib
.VOC/gal thinner (reducer).
"Reference 1.
^References 1, 4, and 9.
Volume of coating:volume of reducer.
?Reference 15.
Calculated value based on one vehicle = 100 ft coated area and
35 percent transfer efficiency.
3-3
-------
Prepcoats provide corrosion resistance and an adhesive surface for
subsequent topcoats, but they do not fill grinder marks and sand
scratches. For this reason, they are frequently used in conjunction with
a primer-surfacer.
Primer-surfacers, which can be used to fill surface imperfections,
are the most versatile primers, providing adhesion, corrosion resistance,
and build (filling ability). The three types of primer-surfacers are
nitrocellulose lacquer, acrylic lacquer, and alkyd enamel. Of the primer-
surfacers, nitrocellulose lacquer primer-surfacer is the most commonly
used, primarily because it dries in 20 minutes and is easier to sand than
the other .primer-surfacers. However, it does not provide the degree of
corrosion resistance and durability offered by the other formulations, so
its use is limited to small repairs.8 Enamel primer-surfacers, which
offer improved corrosion resistance and durability, are generally used for
panel repairs and complete repainting. Drying time for these coatings is
1 to 2 hours. Acrylic lacquer primer-surfacers combine the fast drying of
the nitrocellulose product with the durability of enamels.
Primer-sealers provide the same adhesion and corrosion protection as
prepcoats, some of the filling ability of primer-surfacers, and the
ability to seal an old finish that is being repainted. Drying time is
about 30 minutes* Sealing is necessary to hide sand scratches and to
promote adhesion when spraying alkyd enamel over lacquer, enamel over
enamel, and lacquer over enamel. Sealers differ from primer-sealers in
that they cannot be used as a primer and must be sprayed over a prepcoat,
a primer-surfacer, or an old finish. Primer-sealers are typically enamel-
based, while sealers are acrylic lacquer-based products.
Lacquer-based primers average 5.8 Ib VOC/gal coating, as sprayed,
while enamel-based primers average 5.1 Ib VOC/gal coating, as sprayed.
Waterborne primers offer an alternative to the conventional
solvent-borne primers. While the initial purchase price is higher than
that of lacquer-based primers and enamel-based primers, waterborne acrylic
primers offer the advantages of high filling and sealing capability. In
addition, waterborne primers are impervious to attack by solvents, thus
they prevent the swelling of sand scratches in an old surface caused by
solvents in a new surface. Waterborne primers, unlike conventional
3-4
-------
primers, can be sprayed over old, cracked finishes. The drying time for
10
waterborne primers is comparable to that for enamels.
3.2.3 Topcoats
The topcoat, which is generally a series of coats, is applied over
the primer and determines the final color of the refinished area. Since
most repairs are spot and panel repairs, the automobile refinisher is
concerned with matching the original equipment manufacturer (OEM) color as
closely as possible. Usually, this matching is accomplished by blending
the repair into the surrounding area. The first coat is applied to the
immediate area being repaired, with subsequent coats extending beyond this
area. In some cases, a heavily reduced blend coat is used to further
improve the color match. Because this coat is less dense, it allows a
portion of the original color to show through and effect a gradual
transition from the color of the refinished area to the original
color.If»8»11 As OEM topcoats have become more complex, the precise
matching of original colors by refinishers has become more difficult, and,
in many cases, increased solvent usage has resulted from an effort to
achieve blending.
From the standpoint of appearance, topcoats may be either solid
colors or metallics and may be applied 1n one stage or in a two-stage
basecoat/clearcoat (BC/CC) system for improved gloss and "depth." Three-
stage mica coatings have also been developed.
Metallic finishes differ from solid color finishes because they
contain .small metal flakes, typically aluminum, that are suspended in a
mixture of binders, solvent, and pigment. Light enters the finish and is
reflected by these metal flakes to produce the metallic color effect. As
a result, these finishes are among the more difficult to color match
successfully. The solvents in the coating begin to evaporate as soon as
the material is sprayed. This rate of evaporation.determines the
alignment and depth of the metallic flakes. If evaporation occurs very
quickly, the flakes will be frozen in random patterns near the film
surface, giving the finish a light silvery appearance. Conversely, if
evaporation occurs too slowly, the flakes will sink further, resulting in
a reduced metallic effect and a darker finish.
3-5
-------
Basecoat/clearcoat systems consist of a basecoat, which may be either
a solid color or a metallic (although usually the latter), followed by a
clearcoat. These systems have become popular with vehicle owners because
they provide a deep, rich look that cannot be duplicated by a single-stage
coating.
The chemistry of coating systems, whether solid colors, metal lies,
single stage or two stage, is classified into several categories. These
are: acrylic lacquer, alkyd enamel, acrylic enamel, and polyurethane. A
breakdown of the relative properties and costs for the different types of
topcoat formulations is presented in Table 3-2. The values presented for
each coating type in Table 3-2 are average values for each parameter based
on a review of industry surveys and are not intended to represent a
particular coating. Lacquers account for approximately 34 percent by
volume of the coatings used by the automobile refinishing industry based
on a recent market survey.1 Lacquers are preferred for spot repairs
because they dry quickly by solvent evaporation and are easily redissolved
1n solvent and removed when necessary.8 Alkyd enamel, also referred to as
synthetic enamel, is the chemical combination of an alcohol, an acid, and
an oil. Developed by OuPont in 1929, alkyd enamel is less expensive than
acrylic enamel but has inferior durability. Acrylic enamels, the most
frequently used coating in the automobile reflnishlng Industry, are
characterized by excellent durability. Unlike lacquer coatings, enamels
have a natural high gloss and do not require compounding (polishing),
which reduces labor costs, especially for refinishing panels or entire
vehicles.8 Enamels (Including alkyd and acrylic) account for
approximately 54 percent of the paint currently sold. Polyurethane
coatings, which are the most recently developed coatings, comprise the
1 2
remaining 12 percent of the market. Polyurethane coatings typically are
used by the more technically sophisticated refinishing shops and generally
offer superior gloss retention and durability. They are frequently used
for overall painting jobs, such as painting fleet vehicles.**
There is a difference between the coatings applied by the OEM's and
those applied by refinishing shops. At OEM facilities, coatings once
applied to the vehicles are subsequently baked in large ovens to shorten
drying times and to cure the coatings. Automobile refinishing shops
3-6
-------
TABLE 3-2. TYPICAL TOPCOAT PARAMETERS*
CO
I
Basecoats
Solids content
As sold. wt.|°
As sprayed, Mt.S
Sol Ids content .
As sold, vol.jT
As sprayed, vol .t
VOC content
As sold, Ib/gal coating
As sprayed, Ib/gal coating6
As sprayed, Ib/gal solldsc
Density, Ib/gal
Coating as sold
Coating as sprayedc
Density of sol Ids
Reduction ratio6 '
Dry f lid thickness, mlls^
Volume/vehicle, as sprayed, gal
Cost
As sold, $/gale
As sprayed, S/galc
Per vehicle, S
Acrylic
1 acquer
32
14
25
10
5.2
6.3
62.5
7.7
7.3
11.0
1:1.5
1.5
2.7
72
34
91
Acryl ic
ename 1
46
33
36
24
4.5
5.3
22.2
8.5
8.0
11.0
1:0.5
1.5
1.1
52
38
41
Polyurethane
(isocyanate)
37
37
34
26
5.2
5.2
15.3
8.2
8.2
10.0
1:0.33
1.5
0.8
100
100
80
Acrylic
lacquer
33
11
26
9
5.2
6.4
73.5
7.0
7.0
10.0
1:2.0
2
3.9
31
16
61
Clearcoats
Acryl Ic
enamel
32
32
28
28
5.6
5.6
20.0
8.2
8.2
—
None
2
1.3
22
22
29
Polyurethane
45
45
33
33
4.4
4.4
13.3
9.5
9.5
9.5
None
2
1.1
49
49
54
"The values presented In this table are average values for the parameters listed. The parameters for each coating type are not
Intended to represent a particular coating.
References 1 and 9.
^Calculated values based on recommended reduction ratio and 6.95 Ib VOC/gal thinner (reducer).
Reference 1.
^References 1,4, and 9.
Volume of coat Ing:volume of
^Reference 14. 2
Calculated value based on one vehicle = 100 ft coated area and 35 percent transfer efficiency.
reducer.
-------
cannot use such drying ovens because the high temperatures would likely
damage the car's upholstery, glass, wiring, and plastic fittings. The
coatings used at refinishing shops must have the ability to either air dry
or dry when baked at low temperatures; therefore, automobile refinishing
coatings require solvents that allow the coatings to dry faster.
3.2.4 Application Techniques
Current practice in the automobile refinishing industry is to apply
all coatings, whether primer, basecoat, or clearcoat, using a hand-held
air atomized spray gun. This gun atomizes the coating into tiny droplets
by means of air pressure. The two basic types of spray guns are pressure
feed and.suction feed. In a pressure feed spray system, the paint is
contained in a pressure pot that is connected by hose lines to the spray
gun. Compressed air pushes the liquid out of the spray gun nozzle.
Pressure feed spray guns generally consume significantly more paint than
the suction feed guns due to the paint required to fill the pressure pot
and hose lines. In a suction feed gun, the rapid flow of the air
through the air line above the paint cup creates a vacuum in the paint
intake tube causing the paint to rise and mix with the air before exiting
the gun. The suction gun is the more popular gun and is used almost
exclusively 1n the automotive refinishing industry. The transfer
efficiency, the percent of paint solids sprayed that actually adheres to •
the surface being painted, provided by these guns varies dramatically
depending on the configuration of the part being painted, the type of gun
used, and the skill of the operator, but can be assumed to be approxi-
mately 35 percent.1** Consequently, around 65 percent of the paint that is
sprayed 1s wasted because it does not strike the surface being painted.
Spray booths provide dirt-free, well-lit, and well-ventilated
enclosures for coating application. Because of their longer drying times,
enamel, waterborne, and polyurethane coatings are best applied in a spray
booth to minimize the possibility of dirt adhering to the damp coating.
Spray booth ventilation is necessary to provide clean, dirt-free air to
remove paint overspray and solvent vapors, to hasten drying, and to
provide a safer work environment for the painter. Traditionally, the
airflow 1n spray booths has been horizontal or crossdraft. However,
downdraft booths with vertical airflow (top to bottom) are gaining 1n
3-8
-------
popularity. In the crossdraft design, incoming air is pulled into the
booth through filters located in the entrance door, travels along the
length of the car, passes through paint arrestor filters at the opposite
end which remove paint overspray, and finally exhausts through an exhaust
stack. In contrast, incoming air in a downdraft booth is pulled in
through filters in the roof, travels down over the top of the vehicle to
remove paint overspray, and passes into a grate-covered pit in the floor
of the booth. The downdraft booth is perceived to be the better design
because overspray in the rest of the booth is minimized, air circulation
is more uniformly concentrated around the vehicle, and solvent vapor is
drawn down and away from the breathing zone of the painter.
In order to decrease the drying time after coating application, some
shops use forced drying systems. Large volume shops may have a drying
chamber attached to the back of the spray booth that contains infrared
units mounted in the chamber walls or mounted in a traveling oven that
rolls along the length of the vehicle. At smaller shops, these traveling
ovens may be located in a storage vestibule next to the spray booth to be
rolled out for use inside the booth after the vehicle has been sprayed.
Small, portable infrared units in various sizes are also available either
to warm cold metal surfaces prior to coating application or to speed the
drying time of spot and panel repairs. Forced drying systems typically
are used in shops that use slower drying enamel, waterborne, and
polyurethane coatings to speed drying, which reduces the possibility of
dirt adhering to the damp coating.
Because it 1s Impossible to stock enough paint to match all the
colors used in the automobile industry, many repair shops use an in-Jiouse
color mixing machine system. This system comprises a paint measuring
scale, a catalog of color chips and formulas, and a rack containing forty
to sixty, 1-gallon cans of mixing colors. From these basic colors, almost
any OEM color can be matched and also can be adjusted for fading and
weathering of older finishes. In-house mixing of paints allows the repair
shop to prepare the proper amount of paint needed for each job rather than
buying 1n the unit quantities offered by paint manufacturers. It also
ensures that color matching can be done quickly and that slight
adjustments to the color can be made without having to reorder from the
supplier.
3-9
-------
3.2.5 Equipment Cleanup
The final phase of automobile refinishing consists of cleaning the
spray gun and any other equipment used. Typically, cleanup consists of
thoroughly rinsing the affected equipment with solvent to remove any paint
particles present. The solvent may be reused but is usually discarded.
3.3 REFERENCES FOR SECTION 3
1. Letter from R. Hick, DuPont, Wilmington, Delaware, to R. Blaszczak,
ESD/EPA. Research Triangle Park, North Carolina. February 8, 1988.
2. Industry Profile, Body Shop Business. June 1987.
3. Letter from D. Greenhaus, National Automobile Dealers Association
(NAOA), McLean, Virginia, to R. Blaszczak, ESD/EPA. Research
Triangle Park, North Carolina. February 2, 1988.
4. Minutes of meeting with G. Ocampo, The Sherwin-Williams Company,
Cleveland, Ohio, at EPA/OAQPS, Research Triangle Park, North
Carolina. February 4, 1988.
5. Letter from R. Hick, DuPont, Wilmington, Delaware, to A. Bell, Texas
Air Control Board, Austin, Texas. October 29, 1987.
6. Telecon of conversation between R. H1ck, DuPont, Wilmington,
Delaware, and M. McLaughHn, MRI, Gary, North Carolina. February 5,
1988.
7. Attachment to letter from L. Bowen, South Coast Air Quality
Management District, El Monte, California, to interested parties.
December 30, 1987.
8. Auto Refinishing Handbook, DuPont, Wilmington, Delaware. 1987.
9. Attachment to letter from D. Braun, BASF Corporation, Whitehouse,
Ohio, to R. Blaszczak, ESD/EPA. Research Triangle Park, North
Carolina. February 22, 1988.
10. BASF Corporation, Whitehouse, Ohio, product bulletin. 1988.
11. Minutes of meeting with representatives of the National Paint and
Coatings Association (NPCA), Washington, D.C., at EPA/OAQPS, Research
Triangle Park, North Carolina. January 20, 1988.
3-10
-------
12. Minutes of meeting with representatives of Akzo Coatings (Sikkens),
Norcross, Georgia, at EPA/OAQPS, Research Triangle Park, North
Carolina. December 16, 1987.
13. Attachment and letter from G. Levey, Speedflo Manufacturing
Corporation, Houston, Texas, to R. Blaszczak, ESO/EPA. Research
Triangle Park, North Carolina. January 4, 1988.
14. Attachment to letter from R. RondlnelH, The Devllbiss Company,
Toledo, Ohio, to R. Blaszczak, ESD/EPA. Research Triangle Park,
North Carolina. February 12, 1988.
15. The Sherwin-Wmiams Company, Cleveland, Ohio, product bulletins.
1988.
3-11
-------
4.0 EMISSION ESTIMATES
This section provides VOC emission estimates for each of the
automobile refinishing process steps identified in Section 3 as they are
currently practiced in the industry. These process steps include surface
preparation, primer application, topcoat application, and spraying
equipment cleanup. Emissions of VOC's from automobile refinishing
operations are the result of organic solvent evaporation from these
process steps. Table 4-1 presents the major emission sources within the
industry and the estimated percentage of total nationwide emissions from
each source. The VOC emission estimates presented in this section provide
a baseline with which to compare the emission reduction techniques and
resulting emission reductions discussed in Sections 5 and 6, respectively.
State or local agencies should conduct a survey of shops in their
area to determine their baseline VOC emissions from automobile refinishing
operations. An area survey would likely provide more accurate emission
estimates than using the data presented here because the VOC emissions
presented in this section are based on broad assumptions as outlined in
Section 4.1.
4.1 BACKGROUND
To establish a consistent basis (the baseline) for determining
current VOC emissions from the automobile refinishing industry, typical
coating parameters and facilities were selected based on surveys of the
industry. Appendix A presents the methodology used to develop three
general categories of refinishing shops, the number of jobs per shop per
category, and the coating usage per category. The categories developed
using this methodology include small shops, which perform an average of
6 partial repairs per week; medium-sized shops, which average 13 partial
repairs and 1 complete vehicle job per week; and volume shops, which
typically perform 15 complete vehicle jobs and 14 partial repairs per
week. Table 4-2 presents the typical coating parameters used in
calculating the VOC emission estimates for each type of shop. Table 4-3
summarizes the size, equipment, and coating consumption assumed for each
of the typical facilities. For the purposes of this analysis, it is
assumed that topcoats consist of a basecoat and clearcoat, and that
4-1
-------
TABLE 4-1. VOC EMISSION SOURCES AND PERCENTAGES OF TOTAL
NATIONWIDE VOC EMISSIONS
Percent of
Source total emissions
Surface preparation/cleaning 8
Primers 17
Topcoats 55
Equipment cleaner 20
4-2
-------
TABLE 4-2. TYPICAL COATING PARAMETERS FOR VOC CALCULATIONS
Base coats
Prlaers
Solids content
As sold, voluae percent*
As sprayed, voluae percent11
VOC content
As sold. Ifa/gal coating3
As sprayed. Ib/gal coating"
Reduction ratioc d
Dry fila thickness, alls'
Lacquer1
33
13
4.6
6.0
1:1.5
2
Enanel
36
24
4.1
5.1
1:0.5
2
Water-borne
33
33
2.5
2.5
None
2
Urethane
37
30
3.6
4.3
1:0.25
2
Acryl 1c
lacquer
25
10
5.2
6.3
1:1.5
1.5
Acrylic
enaael
36
24
4.5
5.3
1:0.5
1.5
Polyurethane
(Isocyanate)
34
34
5.2
5.2
Hone
1.5
Lacquer
26
9
5.2
6.4
1:2
2
Clear coats
Enaael
28
28
5.6
5.6
None
2
Higher solids
polyurethane
33
33
4.4
4.4
None
2
"References 1 and 2.
"Calculated value based on reduction ratio.
'References 1 through 3.
^oluae of coating:voluae of reducer.
'Reference 2.
OJ
-------
TABLE 4-3. TYPICAL AUTOMOBILE REFINISHING PAINT USAGE AND EQUIPMENT BY FACILITY TYPE
Facility description
Saatl shop
Hedii* shop (Include
dealers)*
Voluae shop (includes
franchises ]T
Mo. of
facilities Sales. Jobs/week5
nationwide11 c S1.000/yrb Full Partial
32. ZOO <1SO 0 6
41.300 150-750 I 13
8.600 >750 IS 14
Paint usage, gal/wk as sprayed9 Equlpaent
Lacquer Enaael Ur ethane Spray Mixing
P° 8 C P B C PBC booth station
1.6 1.6 2.5 0 0 0 000 No Ho
3.B 3.7 S.B 1.3 1.0 1.2 0 0 0 Yes Mo
000 18.4 13.8 1S.B 4.B 3.1 4.3 Yes Yes
*Assuaes 100 ft2 for full job; 10 ft2 for partial job.
bSee Appendix A.
'Reference 1.
°Prt*er coat * P; basecoat * fi; clearcoat • C.
^Assumes one full job and four partial jobs are coated with lacquer and the regaining nine partial jobs are coated with enaael.
'Assumes II full and 4 partial jobs are coated with enaael and 4 full jobs are coated with urethane.
-------
coating one complete vehicle is equivalent to coating 100 ft of surface
area. Partial jobs (e.g., spot and panel repair) are assumed to average
2
10 ft . Coating usage values were calculated based on the parameters
given in Tables 3-1 and 3-2 and on the following assumptions. Small shops
2,
paint an average of 6 partial jobs (60 ft ) per week and use lacquers
exclusively. Medium shops paint 5 partial jobs (50 ft2) with lacquer,
11 partial jobs (110 ft3) with enamel, and one full job (100 ft2) with
enamel. Volume shops paint 4 partial jobs and 18 full jobs (1,840 ft
total) per week and use enamel for half of the work and urethanes for the
other half.
These assumptions are intended to represent the range of typical
facilities. Because of localized trends within the industry, source-
specific information should be used for determining emission estimates
from this industry in a particular locale, if at all possible. Users of
this document should not attempt to use these values to estimate emissions
from specific shops.
4.2 BASELINE VOC EMISSIONS
The baseline nationwide VOC emissions from the motor vehicle
refinishing industry were calculated from the information in Tables 4-2
and 4-3, and are presented in Table 4-4. Small shops, which typically
perform spot and panel repairs using lacquer coatings and rarely repaint
entire vehicles, account for 15 percent of the total VOC emissions from
this industry (10.2 Ib VOC/d per shop). Medium-sized shops, which include
approximately 17,000 automobile dealerships that maintain body shop
operations, perform a range of repairs and use both lacquers and
enamels. These facilities account for 52 percent of VOC emissions
(29.0 Ib VOC/d per shop). Finally, the high-volume shops, which
specialize in repainting entire vehicles using both enamels and urethanes,
account for 33 percent of the overall emissions (89.0 Ib VOC/d per shop).
4.3 CALCULATIONS
The calculation methodology used to estimate VOC emissions is
presented in Appendix B. Agencies may elect to use this methodology to
calculate VOC emissions from their area if enough information from an area
shop survey is available.
4-5
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-p.
I
en
TABLE 4-4. BASELINE VOC EMISSIONS FROM AUTOMOBILE REFINISHING BY FACILITY TYPE
Facility description
Saall shop
Mediu* shop (includes dealers)
VoluM shop (includes franchises)
Total industry
Mo. of
shops1'6
33.200
41.300
8.600
83.100
Percent of
total Ho.
of shops
40
SO
10
100
Prtaer
1.9
S.9
22.9
6.1C
VOC Missions,
Basecoat
2.0
5.8
17.9
S.5C
, Ib/d per shop
Clear coat
3.2
8.7
21.5
7.8C
Total
Ib VOC/d.
Solvent per shop
3.1 10.2
8.7 29
26.7 89
8.3C 27. 7C
Total
tons VOC/yr.
nationwide
42.200
149.900
95.600
287.700
Percent of
total VOC
emissions
IS
52
33
100
"Reference 6.
Reference 7.
Sfeighted average values.
-------
4.4 REFERENCES FOR SECTION 4
1. Letter from R. Hick, DuPont, Wilmington, Delaware, to R. Blaszczak,
ESD/EPA. Research Triangle Park, North Carolina. February 8, 1988.
2. Attachment to letter from G. Ocampo, Sherwin-Williams, Cleveland,
Ohio, to R. Blaszczak, ESD/EPA. Research Triangle Park, North
Carolina. February 3, 1988.
3. Attachment to letter from D. Braun, BASF Corporation, Whitehouse,
Ohio, to R. Blaszczak, ESD/EPA. Research Triangle Park, North
Carolina. February 22, 1988.
4. DuPont Auto Refinishing Handbook, The DuPont Company, Wilmington,
Delaware. 1987.
5. Minutes of meeting with representatives of Akzo Coatings (Sikkens),
Norcross, Georgia, at EPA/OAQPS, Research Triangle Park, North
Carolina. December 16, 1987.
6. Industry Profile, Body Shop Business. June 1987.
7. Letter from D. Greenhaus, National Automobile Dealers Association
(NADA), McLean, Virginia, to R. Blaszczak, ESD/EPA. Research Triangle
Park, North Carolina. February 2, 1988.
8. Letter from L. Bowen, California South Coast Air Quality Management
District, El Monte, California, to interested parties. December 30,
1987.
9. The National Paint and Coatings Association, Washington, D.C. The
U. S. Paint Industry: Technology Trends, Markets, Raw Materials.
September 1986.
4-7
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5.0 EMISSION REDUCTION TECHNIQUES
This section presents information on VOC emission reduction
techniques and alternative low-VOC coatings that currently are available
to reduce VOC emissions from the automobile refinishing industry. The
information will allow planners to identify advantages and disadvantages
associated with the implementation of these options. The options may be
used singly or in combination to achieve required VOC reductions. Options
are available for each of the four process steps involved in automobile
refinishing.
Sections 5.1, 5.2, 5.3, and 5.4 present alternatives for reducing VOC
emissions during vehicle preparation, primer application, topcoat
application, and equipment cleanup, respectively. The VOC emission
reductions associated with implementation of these options are presented
in Chapter 6.
5.1 ALTERNATIVES FOR REDUCING VOC EMISSIONS DURING VEHICLE PREPARATION
As discussed in Section 3.0, vehicle preparation is critical in
assuring proper coating adhesion to the vehicle. Failure to properly
clean the surface to be painted may result in the need to reapply the
coating, resulting in Increased labor and raw materials cost, and
increased VOC emissions. The conventional vehicle preparation procedure
is a two-step process. The surface is washed with detergent and copious
volumes of water, followed by a thorough cleaning with solvent to remove
grease, wax, si 11cones, and other possible contaminants. However,
reduced-VOC cleaners and detergents are two alternatives to the standard
practice that can be used to reduce VOC emissions.
5.1.1 Reduced-VOC Cleaners
At least one major coating supplier offers a product for use during
the second step of vehicle preparation that contains less than 20 percent
of the VOC found in conventional cleaners. This aqueous-based cleaner,
introduced in late 1981, contains 80 percent water, 15 percent solvent (a
mixture of toluene and xylene), and 5 percent surfactant.3 The resulting
emulsion, which has the appearance of heavy cream, was formulated for
degreasing surfaces for spot repair. Despite its claimed superior
cleaning efficiency in this application, it has not gained widespread
5-1
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acceptance in the refinishing industry because it is inherently limited to
removing wax and grease during preparation, and is not a general purpose
solvent. Typically, body shop owners prefer to purchase those solvents
that have multiple uses in the shop (e.g., vehicle preparation, paint
thinning, and cleanup) to minimize inventory.3 Use of this or a similar
cleaner would, however, reduce worker exposure to VOC's during vehicle
preparation, and reduce overall VOC emissions.
5.1.2 Detergents
The use of a second detergent wash to clean the vehicle is an option
that would totally eliminate VOC emissions during vehicle preparation.
While the 'typical automobile refinisher relies upon the use of a solvent
rinse, detergents alone have been used successfully for many metal
cleaning applications.1*1 One area of concern is the complete removal of
silicones, which, if present, tend to cause a common coating defect called
"fish eyes." These are small, crater-like openings in the new finish
where silicones have prevented the coating from leveling to a smooth
finish. In order to avoid this defect, refinishers tend to use solvents
rather than detergents. Nonetheless, when properly used, detergents are
effective in cleaning the metal surfaces to be coated. Furthermore,
commercial products are available that will reduce the surface tension of
the coating film, thus allowing it to flow over and around any
1 K g
contamination (such as silicone) that might be present. *
5.2 ALTERNATIVES FOR REDUCING VOC EMISSIONS DURING PRIMER APPLICATION
Two alternatives for reducing VOC emissions are improving transfer
efficiency (the percentage of the coating sprayed that actually adheres to
the surface being coated), and using lower-VOC primers (waterbornes and
urethanes) in place of conventional lacquer and enamel primers.
5.2.1 Improved Transfer Efficiency
As discussed in Section 3.0, the spraying equipment preferred by the
automobile refinishing industry is the conventional hand-held air-
atomizing gun, which is typically outfitted with a 1-quart cup and has an
7 3
estimated transfer efficiency of approximately 35 percent. * This rate
of transfer efficiency means that approximately 65 percent of the coating
sprayed falls to deposit on the vehicle, resulting 1n unnecessary coating
consumption and VOC emissions. Two alternative coating application
5-2
-------
techniques, both of which allow transfer efficiencies up to 65 percent,
are electrostatic spraying and high-volume, low-pressure (HVLP)
. 9-11
spraying.
Electrostatic spraying involves using an electrical transformer
capable of delivering up to 60,000+ volts to create an electrical
potential between the paint particles and the surface of the vehicle.
These charged paint particles are thus electrically attracted to the
surface, increasing transfer efficiency. Although used by original
equipment manufacturers in great numbers, electrostatic spraying has not
been adopted by the automobile refinishing industry for three primary
reasons.7*1Z One problem is that typically these systems use a pressure
pot connected to the spray gun via a hose. Coating is left over in the
hose after each job. Since color changes occur with each job, this extra
material is discarded (once mixed with the appropriate reducer and
additives, most coatings have a limited pot life, or period in which they
are usable). This offsets coating savings through the increased transfer
efficiency. Another factor is the cost of the electrostatic system. A
typical air-atomized spray gun costs around $160 (excludes hoses, air
regulator, and compressor), while an electrostatic gun costs from $3,000
to $5,000 (includes gun, power cable, and power supply and excludes
compressor, hoses, air regulator). »: fl The compressor, hoses, and air
regulator for each system can cost an additional $2,000 to $3,000.8
Finally, electrical shocks and fire hazards are two potential safety
problems associated with electrostatic spraying, although the degree of
hazard 1s controversial.10'1** For these reasons, the use of electrostatic
spraying is probably not a practical option for the majority of the
refinishing industry.
High-volume, low-pressure spraying, also known as turbine spraying,
involves the use of a turbine to generate and deliver atomizing"air. The
turbine draws in filtered air which is driven through several stages at up
to 10,500 revolutions per minute (rpm).11 The result is a high volume of
warm, dry, atomizing air that is delivered to the spray gun at less than
7 pounds per square Inch (psl).11 This low-pressure air gives greater
control of the spray, with less overspray and paint fog due to the absence
of the blasting effect common with conventional high-pressure systems.
5-3
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This blasting effect 1s caused when the compressed air released from the
gun suddenly expands and returns to atmospheric conditions, which tends to
over-atomize the coating and propel it at high velocity, causing
overspray, rebounding, and fog, and reducing transfer efficiency. At
present, less than 5 percent of automotive refinishers use HVLP
spraying. The cost of HVLP equipment varies significantly ranging from
around $1,000 for a basic one-gun system, up to $18,000 for a heavy-duty
complete system with multiple guns. However, the potential savings in
paint usage due to the higher transfer efficiency over conventional
equipment makes the HVLP equipment an attractive option for coating
application.
5.2.2 Waterborne Primers
Waterborne primers formulated for the requirements of automobile
refinishing recently have been developed and currently are offered by at
least one supplier. These primers typically contain 2.5 Ib VOC/gal (as
sprayed) compared with the 6.0 Ib VOC/gal and 5.1 Ib VOC/gal (as sprayed)
typically contained 1n conventional lacquer and enamel primers, respec-
tively. Unlike conventional primers, waterborne primers do not require
that old, cracked and crazed finishes be stripped prior to application of
the primer because the primer fills in the cracks. According to the
manufacturer, these primers can be topcoated with virtually any topcoat
system including basecoat/clearcoat systems. In addition, waterborne
primers are not subject to attack by solvents in the topcoats, eliminating
sandscratch swelling, lifting, or other coating problems. They also can
be applied with conventional spray equipment. The major disadvantage with
waterborne primers, from the refinlsher's perspective, 1s the relatively
long drying time associated with these formulations—60 minutes as opposed
to 20 to 30 minutes for conventfonal primers. * This increased drying
time interferes with the timely refinish of the vehicle and, depending on
the workload and available space in the shop, may leave the painter with
no productive work for that hour. Furthermore, the drying times of
waterborne coatings vary greatly with changes in temperature and humidity,
factors which are often difficult to control under shop conditions.
Waterborne primers are, however, cost competitive with lacquer and enamel
primers. Slow drying time and sensitivity to ambient conditions, along
5-4
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with shop unfamillarity with these relatively new products, probably
explains why these products currently account for less than 6 percent of
the total volume of primer sold in the United States.
5.2.3 Urethane Primers
The use of urethane primers is another option for reducing VOC
emissions from the automobile refinishing industry. These primers
typically contain 4.3 Ib VOC/gal (as sprayed) compared with the 6.0 Ib
VOC/gal and 5.1 Ib VOC/gal (as sprayed) contained in conventional lacquer
and enamel primers, respectively. These products provide excellent
filling of scratches and holdout (the ability of a primer to prevent the
topcoat from sinking into it).17 Drying times, however, average about
45 minutes, and urethane primers may also contain isocyanate hardeners.
The presence of isocyanates requires the use of supplied-air respirators,
which are not available at many shops. ' Urethane primers also cost
about 25 percent more than conventional lacquer primers and about
50 percent more than conventional enamel primers.
5.3 ALTERNATIVES FOR REDUCING VOC EMISSIONS DURING TOPCOAT APPLICATION
5.3.1 Improved Transfer Efficiency
Methods of improving transfer efficiency were discussed in
Section 5.2.1, and that information generally applies to the application
of topcoats. However, there are additional considerations rela'ted to
color matching that warrant discussion.
5.3.1.1 Color Coats. The unique problem associated with applying
topcoats that is not an issue for primer or clearcoat application is the
problem of color match. Approximately 90 percent of the refinishing work
in a typical shop involves spot repairs, and customers will reject an
otherwise satisfactory repair if the color of the repaired area fails to
match the rest of the vehicle. Shops frequently must blend the refinish
color over the original color to reduce the disparity between the original
and repair colors as much as possible. Color can also be varied by
adjusting the amount of solvent used to thin the paint, the speed
(volatility) of the solvent, the distance between the gun and the surface
being painted, and the air pressure used. For example, the painter could
hold the gun farther from the surface thereby creating a thinner coat and
allowing the original color to show through.
5-5
-------
Metallic finishes, which have become very popular, present additional
color matching difficulties. These finishes, which include small flakes
of aluminum, depend on the proper alignment of these flakes for optimum
appearance. This alignment, in turn, is dependent upon the rate of
solvent evaporation.
High transfer efficiency spray guns may make color matching more
difficult because they tend to produce thicker coats which makes it more
difficult to apply increasingly thinner coats of paint when blending or
feathering. The problems associated with the application of metallic
coatings are also exacerbated when high transfer efficiency equipment is
used since film thickness affects the evaporation rate of solvent which
determines the positioning of the metallic flakes in the coating. Another
adverse effect of a higher transfer efficiency is splotching, which is
caused when solvent initially trapped in the thicker coating escapes to
the surface and causes a blemish.
Based upon conversations with several facilities in California, it
appears that the HVLP equipment is being used with some success. The
manager at one shop stated that it 1s the painter who determines the
quality of the job.19 He stated that the HVLP spray gun has a different
feel than the conventional air-atomizing spray gun and it takes some time
to get accustomed to its use.1 A painter from another shop maintained
that, Initially, some problems were encountered with color match. How-
ever, experience with the equipment and changing the paint-to-solvent
ratio to 1:1 instead of the recommended reduction ratio solved these
problems and provided excellent results on a wide range of vehicles.20
This solution, however, points out a potential problem with implementing
the use of high transfer efficiency equipment to reduce VOC emissions. If
the coating is further reduced with solvent, the advantage of a higher
transfer efficiency will be partially or totally offset. Proper operator
training will be required. Another shop is currently applying primers
with HVLP and expects to apply topcoats with it in the near future.21 It
appears that while some drawbacks exist with the use of HVLP, these may be
overcome with experience. As with any change in operating procedures,
some resistance may be encountered from body shop operators if a change
from the conventional spray gun to the HVLP spray gun is implemented.
5-6
-------
Nevertheless, the California South Coast Air Quality Management District
is proposing to require a minimum 65 percent transfer efficiency for spray
equipment. This requirement is based on observation of the HVLP
equipment.
5.3.1.2 Clearcoats. There are no significant technical reasons for
not using high transfer efficiency spray equipment to apply clearcoats.
The industry probably has not yet done so because of the relative newness
of the technology, operator unfamiliarity with the equipment, and initial
capital cost. Also, shop owners are probably reluctant to maintain two
types of systems, a conventional system for color matching shop repairs,
and a high transfer efficiency system (HVLP) for primers, clearcoats, and
completely repainting vehicles.
5.3.2 Reduced-VOC Coatings
The use of coatings that contain a lower concentration of VOC's
(higher solids content) than the baseline coatings will result in a
reduction of VOC emissions. Lacquers generally have the highest VOC
content of the coatings applied in this industry. The replacement of
these coatings with enamels can reduce VOC emissions significantly.
Likewise, the replacement of lacquers or enamels with polyurethane
coatings further reduces emissions. Contemporary polyurethane clearcoats
typically have a solids content, as purchased, of 45 percent by weight,
compared to about 32 percent by weight for a typical lacquer or enamel
clearcoat. The emission reduction potential for polyurethane coatings is
even more apparent when considered in terms of the VOC usage required to
deposit 1 gallon of solids on the automobile. Polyurethane clearcoats
typically contain about 13 pounds of VOC per gallon of coatings solids (Ib
VOC/gal solids). Enamels contain about 20 Ib VOC/gal solids, and lacquers
typically contain about 73 Ib VOC/gal solids. This dramatic increase in
VOC content of lacquers results from the solvent additions that must be
made at the repair shop prior to spraying the materials.
Low-VOC coatings (primarily polyurethanes) have been adopted by many
automobile manufacturers for their production lines. The performance of
these coatings is, in most aspects, superior to that of lacquers and
enamels. Refinishing shops have been much slower to adopt polyurethane
coatings, primarily because of the longer drying times. However, recent
5-7
-------
advances in the coating chemistry have reduced the drying time of poly-
urethanes to a range of 4 to 6 hours. These drying times can be reduced
even more if forced drying (using heat lamps, for example) is used.
Another advantage of most higher solids coatings is the reduction in
the number of coats that must be applied to achieve the desired dry film
thickness. Two or three coats of polyurethane coatings can normally be
used in cases where four to six coats of lacquer would be required. The
combination of superior performance, the requirement for fewer coats than
enamels or lacquers, and improved drying times has made higher solids
coatings more acceptable to auto refinishers.
Research is being conducted by several paint formulators to produce
coatings with even higher solids contents. Increases in solids content
(up to 45 percent) have been accomplished by using strong solvents
(solvents with the ability to dissolve large quantities of a particular
resin while maintaining a sprayable viscosity). In order to increase
paint solIds content beyond 45 percent while continuing to maintain
satisfactory spray characteristics, the viscosity of the paint polymers
must not be allowed to Increase. Lower molecular weight polymers (i.e.,
shorter chain molecules) allow viscosities to be maintained, but there is
a corresponding decrease 1n certain coating properties, especially
durability. Research has not overcome this problem, and these coatings
are not yet available to the automobile refinishing industry.
5.4 ALTERNATIVES FOR REDUCING VOC EMISSIONS DURING EQUIPMENT CLEANUP
The solvent cleaning of leftover paint from the spray equipment
typically results 1n a significant quantity of VOC enissions. Systems are
available, however, that can reduce cleaning solvent consumption and,
therefore, VOC emissions. The simplest of these systems, usually called a
gun washer, consists of a closed container fitted with hose connections.
The spray gun is placed in the container, and the hoses are connected to
the suction and discharge nozzles of the spray gun. Solvent is then
pumped through the gun and back to the enclosed storage receptacle.
Because the system operates as a closed loop once the gun is attached,
there is considerably less spillage and less solvent evaporation than in
the standard practice. Solvent 1s recirculated through the gun washer
system until 1t 1s too contaminated for further use. The number of guns
5-8
-------
that can be cleaned with one solvent charge is highly variable and depends
primarily on the quantity and characteristics of the coatings used in the
guns. However, solvent consumption is typically reduced by 75 to
22 23
80 percent compared to conventional gun cleaning. '
The spent solvent from a gun washer system may be sent out of the
facility for recovery or disposal or it may be recovered in-house using a
distillation system. Small distillation systems that are capable of
21* 25
recovering around 90 percent of the spent solvent are available. ' The
residue from these systems may be used as a rustproofing undercoat for
vehicles.
5.5 ALTERNATIVES FOR SHOP ADD-ON CONTROL OF VOC EMISSIONS
Add-on controls are an option that may be applied to the auto
refinishlng industry to reduce VOC emissions from spray booths. Potential
add-on controls include thermal Incineration, catalytic incineration, and
carbon adsorption. Thermal Incineration has been used successfully in OEM
spray booths to control emissions. However, even though the application
of add-on controls to automobile refinishing operations is technically
feasible, it has been limited. Data on the number of automobile
refinlshlng operations in this country, if any, using add-on controls were
not obtained during this study. Cost is the primary limiting factor in
applying add-on controls 1n the automobile refinlshing industry. The
intermittent use of the spray booths in this industry generates an
intermittent high-volume air stream with low concentrations of VOC's that
is costly to control with add-on techniques. In addition, small
facilities that do not have a spray booth also would need to Install a
spray booth before an add-on control could be used.
A recent study conducted for the State of New Jersey evaluated the
use of thermal incineration, carbon adsorption, and catalytic incineration
for control of automobile refinishing spray booth emissions in New
Jersey. Although all of the alternatives Investigated were found to have
some technical limitations in their applicability to automobile
refinishing, they are technically feasible.1**
Thermal incineration is capable of achieving 99 percent destruction
of VOC. Because the spray booths are not used continuously, long lead
times to bring the Incinerator up to operating temperature would be
5-9
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required. The fuel requirements needed to incinerate the large volume of
air with a low concentration of VOC (including the fuel needed for
frequent startups) is high. The combustion of the fuel results in NOX
formation and since NOX also is a precurser to ozone, the benefit of
reducing VOC's is partially offset.11*
The positive and negative aspects of catalytic incineration are
similar to those of thermal incineration. High destruction efficiencies
can be achieved. The fuel requirements will be lower, because VOC
destruction is achieved at a lower temperature (900°F) than that required
for a thermal incinerator (1400°F). The potential for fouling the
catalyst exists because the spray booth exhaust gas stream contains
particulate matter.
Although carbon adsorption is a well established VOC control
technique, its application to the automobile refinishing industry poses
some problems. The potential problems are primarily due to the low VOC
content of the air stream being treated and to the intermittent nature of
the spray booth operation. During the painting process, several spray
coats are applied; the coats are allowed to dry between applications.
Consequently, the VOC concentration in the air stream to the carbon
adsorber varies widely. During the drying period, relatively pure air
will be passing over the carbon beds, which could result in VOC desorbing
from the beds.
5.6 REFERENCES FOR SECTION 5
1. DuPont Auto Refinishing Handbook. E. I. du Pont de Nemours &
Company, Wilmington, Delaware. 1987.
2. Summary of presentation by R. Hick, DuPont, Wilmington, Delaware, to
the Technical Review Group of Automotive Refinishing, California A1r
Resources Board. San Diego, California. October 20, 1982.
3. Telecon of conversation between B. H1ck, DuPont, Wilmington,
Delaware, and M. Mclaughlin, MRI, Gary, North Carolina. February 5,
1988.
4. Brady and Clauser, Materials Handbook. McGraw-Hill, New York, New
York. 1977-
5. Baumeister and Marks, Standard Handbook for Mechanical Engineers, 7th
Ed. McGraw-Hill, New York, New York. 1967.
5-10
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6. Product bulletin, BASF Corporation. Whltehouse, Ohio. 1987.
7. Letter and attachment from G. Levey, Speeflo Manufacturing
Corporation, Houston, Texas, to R. Blaszczak, ESD/EPA, U. S.
Environmental Protection Agency. Research Triangle Park, North
Carolina. January 4, 1988.
8. Letter and attachments from R. Rondinelli, The DeVilbiss Company,
Toledo, Ohio, to R. Blaszczak, ESD/EPA. Research Triangle Park,
North Carolina. February 12, 1988.
9. Letter from M. Bunnell, Can-Am Engineered Products, Livonia,
Michigan, to R. Blaszczak, ESD/EPA. Research Triangle Park, North
Carolina. December 29, 1987.
10. Letter from A. Walberg, Electrostatic Consultants, Downers Grove,
Illinois, to J. Berry, CPB/OAQPS. Research Triangle Park, North
Carolina. November 30, 1987.
11. Questionnaire response from K. Marg, Bessam-Aire, Inc., Cleveland,
Ohio to R. Blaszczak, ESD/EPA. Research Triangle Park, North
Carolina. January 8, 1988.
12. Questionnaire response and attachments from L. Utterback, Ransburg-
GEMA, Indianapolis, Indiana, to R. Blaszczak, ESD/EPA. Research
Triangle Park, North Carolina. February 29, 1988.
13. Questionnaire response from A. C. Walberg, President, Electrostatic
Consultants Company, Downers Grove, Illinois, to R. Blaszczak,
Emission Standards Division, OAQPS, U. S. Environmental Protection
Agency, Research Triangle Park, North Carolina. January 18, 1988.
14. Radian Corporation, Austin, Texas. Economic, Energy, and
Environmental Impacts-of Add-On VOS Controls on the Automobile
Refinishing Industry in New Jersey. August 31, 1987.
15. New York State Department of Environmental Conservation, Albany, New
York. An Evaluation of Alternatives to Reduce Emissions from
Automobile Refinishing in the New York Metropolitan Area.
August 1987.
16. Letter and attachments from D. Braun, BASF Corporation, Whitehouse,
Ohio, to R. Blaszczak, ESD/EPA. Research Triangle Park, North
Carolina. February 22, 1988.
17. Attachments to letter from G. Ocampo, The Sherwin-Williams Company,
Cleveland, Ohio, to R. Blaszczak, ESD/EPA. Research Triangle Park,
North Carolina. February 3, 1988.
18. Minutes of meeting with G. Ocampo, The Sherwin-Wmiams Company,
Cleveland, Ohio, to R. Blaszczak, ESD/EPA. Research Triangle Park,
North Carolina. February 4, 1988.
5-11
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19. Telecon of conversation between J. Moore, Manager, Selman Chevrolet,
Orange, California, and M. Turner, Midwest Research Institute, Gary,
North Carolina. June 21, 1988.
20. Telecon of conversation between F. Paolini, Pasha Group, Long Beach,
California, and M. Turner, Midwest Research Institute, Gary, North
Carolina. June 21, 1988.
21. Telecon of conversation between G. Squyres, Gordon Body Shop, Inc.,
Redondo Beach, California, and M. Mclaughlin, MRI, Gary, North
Carolina. February 16, 1988.
22. Letter and attachments from M. Carney, Safety-Kleen, Inc., Elgin,
Illinois, to D. Salman, ESD/EPA. Research Triangle Park, North
Carolina. April 14, 1987.
23. Product Bulletin from Herkules Equipment Corporation, Walled Lake,
Michigan. 1987.
24. Product Bulletin from Paulee Equipment Sales, Inc., Culver City,
California. 1987-
25. Product Bulletin from BT Associates, Inc., Garden Grove,
California. 1987.
5-12
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6.0 ENVIRONMENTAL ANALYSIS
This section discusses the environmental Impacts associated with
Implementation of the various alternative control technologies discussed
1n Section 5.0, either alone or in combination with each other. The
primary emphasis is on a quantitative assessment of VOC emissions in the
absence of control technology (baseline emissions) and after implementa-
tion of one or more of the control alternatives. The impacts of these
control technologies upon water quality, solid waste, and energy
consumption are also briefly discussed in this section.
6.1 AIR POLLUTION
The Implementation of any of these control alternatives would reduce
VOC emissions from automobile reflnishing operations. The procedures for
calculating VOC emissions are presented in Appendix A. The estimated VOC
reduction potential for each technique is presented in Table 6-1. These
values are calculated using the coating parameters and facility charac-
teristics presented in Section 4.0. For each reduction technique, the
resulting VOC emissions (Ib/d) from a typical small, medium, and volume
shop are presented. The total estimated VOC emissions (tons/yr) resulting
from Implementing each technique at all shops nationwide also are
presented. Finally, for each technique, the reduction from baseline in
tons/yr and percent are presented. Although each of the techniques is
presented separately, several techniques could be Implemented together to
reduce emissions from this industry further. Solvent recovery systems and
HVLP spraying, for example, could be used in conjunction with any of the
other options, such as replacement of lacquers with either enamels or
urethanes.
6.2 OTHER CONSIDERATIONS
6.2.1 Water Pollution
The implementation of any of these control technologies would result
in no adverse water pollution impacts because no hazardous wastewater is
produced by these operations. Wastewater from cleanup after spraying
waterborne primers would be processed through the local wastewater
treatment system.
6-1
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TABLE 6-1. COMPARISON OF VOC EMISSIONS FROM AVAILABLE REDUCTION TECHNIQUES
en
I
ro
Reduction technique
Current practice (baseline)
Replace lacquers with acrylic enamel s° c
Replace lacguers and enamels with
urethanes
Replace solvent-borne primers with
waterborne primers0
Replace conventional cjearcoats with
higher-solids clears0
Install solvent recovery systems
Replace conventional air-atomizing spray
guns with high-volume,, low-pressure
(HVLP) spray equipment0 e
Smal I
shop
10.2
5.5
4.7
7.7
7.6
8.6
6.9
Facility VOC
Medium
shop
29.0
18.2
15.2
21.8
22.6
24.7
19.6
emissions.
Volume
shop
89.0
89.0
72.6
65.1
83.1
75.6
60.2
Ib/d
Weighted
average
27.7
20.5
17.0
20.6
22.9
23.5
18.7
Total VOC
emission*,
tons/yr
287,700
212,500
176,000
214,500
237,500
244,500
194.500
Reduction
from
base! Ine,
tons/yr
NA°
75,200
111,700
73,200
50,200
43,200
93,200
Percent
reduction
NA
26
39
25
17
15
32
Note: While certain control alternatives can be combined, VOC percent reductions are not additive in all cases.
"Not applicable.
Assumes baseline solvent consumption.
^Assumes that small shops will acquire the ability to spray enamels (I.e., acquire spray booths).
Assumes 75 percent recovery of spent solvent and no recovery of surface preparation solvents.
"Assumes a 65 percent transfer efficiency (the baseline condition assumes 35 percent).
-------
6.2.2 Solid Waste Disposal
The quantity of solid waste generated by implementation of these
technologies would be insignificant. The waste generated would consist of
used solvent, which could be recovered through distillation either onsite
or at a commercial recycling facility. The resultant still bottoms could
be used either for sound deadening or as an undercoat for corrosion
prevention.1'2 The filters used to collect overspray in the spray booth
would be disposed of in a local municipal waste facility.
6.2.3 Energy
The implementation of these control technologies would result in an
insignificant change in energy consumption. The increased use of spray
booths would result in a slight increase in energy consumption from the
operation of fans for the ventilation system and from heat lamps used to
accelerate drying of enamel and urethane coatings. The HVLP spraying
equipment, however, uses less energy than the conventional high-pressure
equipment.
6.3 REFERENCES FOR SECTION 6
1. Product Brochure, Paulee Equipment Sales,. Inc., Culver City,
California. 1987-
2. Product Brochure, BT Associates, Garden Grove, California. 1987.
3. Letter and attachments from R. Rondinelli, The Oevilbiss Company,
Toledo, Ohio, to R. Blaszczak, ESO/EPA. Research Triangle Park, North
Carolina. February 12, 1988.
4. Attachment to questionnaire response from K. Marg, Bessam-Aire, Inc.,
Cleveland, Ohio. January 8, 1988.
6-3
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7.0 CONTROL COST ANALYSIS
A cost analysis was performed for each type of facility (small,
medium, and large) introduced in Sections 3 and 4. Various emission
reduction options were evaluated for each shop type. These options
included the following: replace lacquers with acrylic enamels; replace
lacquers and enamels with urethanes; replace solvent-borne primers with
waterborne primers; replace conventional clearcoats with higher solids
clears; install cleanup solvent recovery systems; replace conventional
air-atomizing spray guns with HVLP spray equipment; and add-on a thermal
incinerator to the spray booth (volume shop only).
The costs presented in this chapter were developed using the facility
data given in Table 4-3 and costs generated through industry surveys. The
costs should be used for comparison purposes only because the parameters
used to generate the costs will likely vary considerably. This chapter
presents the cost methodology planners can use to perform their own cost
analysis based on area shop surveys. Alternatively, the costs presented
in this section may be used as default values. Section 7.1 presents the
basis for the capital costs, Section 7.2 presents the basis for annualized
costs, and Section 7.3 discusses the emission reduction cost and cost
effectiveness.
7.1 BASIS FOR CAPITAL COSTS
Table 7-1 presents the capital equipment costs for each model shop
for various pieces of equipment including conventional high-pressure, air-
atomized spray equipment, spray booths, HVLP spray equipment, mixing
stations, solvent recovery systems, and add-on controls. It is assumed
that a one-compressor system will support two spray guns. The spray booth
capital costs are based on the cost for a commercial crossdraft booth
($10,000) for the small shops and for a commercial downdraft booth
($50,000) for the medium and volume shops. The volume shops were assumed
to require two spray booths to handle their large production volume. The
shop's existing compressor, hoses, etc., will not be usable in conjunction
with the HVLP equipment, so these costs are based on installation of a
complete system. The cost of mixing stations was included where HVLP was
used because with increased transfer efficiency spray equipment, smaller
7-1
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TABLE 7-1. CAPITAL EQUIPMENT COSTS, IN $
Equipment description
Small
shop
Medium
shop
Volume
shop
Conventional spray equipment (two guns
per compressor)
Spray booth4
High-volume, low-pressure (HVLP) spray
equipment
Mixing station0
Solvent recovery system
Add-on control (thermal Incinerator)
3,500
7,000 10,500
10,000 50,000 100,000
12,000 15,000 18,000
700 2,800 4,200
600 600 1,200
150,000
^References 4 and 8.
Reference 5.
^Reference 3.
Reference 6.
7-2
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quantities of coatings will be required. The installation of a mixing
station will allow the facility to mix only the quantity of coating
required. The capital costs for the medium and volume shops include the
cost of two units each because both of these types of shops use two
different paint chemistries and would require two dedicated units.
Capital costs for solvent recovery systems are for an enclosed spray gun
cleaning and recycling station and include one unit for small and medium
shops and two units for the volume shop. It is assumed that the solvent
will be reused to clean as many guns as practical before being discarded.
The relative costs and benefits of solvent recovery through distillation
are not included.
The capital cost of an add-on control (thermal incinerator) for the
volume shop was estimated using the procedure in the EAB Control Cost
Manual. l The assumptions made include: (1) control of a total gas
stream of 24,000 scfm (two spray booths); (2) an incinerator temperature
of 1600°F with no heat recovery and operating for 8 hours per day; and
(3) a total capital investment cost of 1.5 times the capital equipment
cost. Appendix C provides further details of the"add-on control cost
estimates.
7.2 BASIS FOR ANNUALIZED COSTS
7.2.1 Annualized Raw Material Costs
Typical coating costs, in dollars per gallon, are presented in
Table 7-2. The cost of thinner or reducer used with each coating and the
cost of the surface preparation solvent are assumed to average $8.10 per
gallon. The cost of the low-VOC, aqueous-based cleaner described in
Section 5.1.1 was not Included in any of the cost analyses. However,
while the cost of this material 1s $13.60 per gallon, the cost to prepare
a given area of an automobile for refinlshing would be comparable to that
of solvent because it covers more area per unit volume.10 As discussed in
Section 4.0, typical small facilities are assumed to coat the equivalent
of 60 ft (6 partial jobs) per week, medium-sized facilities coat
230 ft (13 partial jobs and 1 full job) per week, and volume shops coat
1,640 ft (14 partial jobs and 15 full jobs) per week. The coating usage
1s presented in Section 4.0. Total coating cost, in dollars per job, is
calculated as follows:
7-3
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TABLE 7-2. TYPICAL COATING COSTS, $ PER GALLON
Reduction
Coating As sold3 ration" As sprayed0
Primers
Lacquer 27 1:1.5 16
Enamel 31 1:0.5 23
Waterborne 38 None 38
Urethane 53 1:0.25 42
Base coats
Acrylic lacquer 72 1:1.5 34
Acrylic enamel 52 1:0.5 37
Polyurethane (isocyanate 100 None 100
catalyzed)
Clear coats
Lacquer 31 1:2 16
Enamel 22 None 22
Polyurethane (higher-solids) 49 None 49
^References 1 and 2".
References 1, 2, and 3.
Calculated values based on reduction ratio and an average thinner/reducer
cost of $8.10/gallon.
7-4
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Ct = (VpCp+VbCb+VcCc+JpCs)
where
Ct = the total coating cost in dollars per partial job
Vp = the volume of primer sprayed, in gallons per partial job
Cp = the primer cost, in dollars per gallon, as sprayed
Vb = the volume of basecoat sprayed, in gallons per partial job
Cb = the basecoat cost, in dollars per gallon, as sprayed
Vc = the volume of clearcoat sprayed, in gallons per partial job
Cc = the clearcoat cost, in dollars per gallon, as sprayed
Jp = the volume of cleanup solvent used, in gallons per partial job
Cc = the cleanup solvent cost, in dollars per gallon
Annualized coating costs are calculated as follows:
Ca * Ct(N)50 weeks/yr
where
Ca = the annual cost, in dollars per year
Ct = the total coating cost in dollars per job
N = the number of partial jobs performed per week
7.2.2 Annualized Equipment Costs
Annualized equipment costs are based on the capital costs presented
in Table 7-1 and an interest rate of 9.5 percent. The interest rate is
based on the commercial loan rate (one point above the prime rate) quoted
in the March 8, 1988, issue of the Wall Street Journal. Equipment life is
estimated to be 10 years. The annual ized equipment cost is calculated by
the following equation:
AEC . P (1
where
AEC = the annual ized equipment cost in dollars per year
P = the installed cost of the equipment in dollars
n = the life of the equipment in years
1 = the annual interest rate =9.5 percent
7-5
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7.2.3 Annual 1zed Operating Costs for Add-On Controls
Annual1zed operating costs for the thermal incinerator were estimated
using the procedures in the EAB Control Cost Manual.11 Appendix B
provides details of the operating cost estimates.
7.3 EMISSION REDUCTION COSTS AND EFFECTIVENESS
The costs and effectiveness of the various alternatives for reducing
VOC emissions from the automobile refinlshlng industry are presented in
Tables 7-3 (small shop.), 7-4 (medium-sized shop), and 7-5 (volume shop).
For the small facility, it was assumed that lacquers were used
exclusively in primer, basecoat, and clearcoat applications and that the
facility'does not own a spray booth. Spray booths are not required for
the application of lacquers. Consequently, the use of alternatives that
involve the replacement of topcoats (i.e., replacing lacquers with acrylic
enamels, replacing lacquers and enamels with urethanes, or replacing
conventional clearcoats with higher solids clears) will include an
additional capital and annual 1zed equipment cost for a spray booth. The
capital cost of the spray booth is estimated at $10,000.
For the small facilities, replacing lacquers or enamels with
urethanes and replacing conventional clearcoats with higher solids
clearcoats each results in an additional cost of $l,200/yr. The higher
cost is due almost entirely to the cost of the spray booth required to
apply the alternative coatings. However, there is a cost savings of
$l,200/yr for replacing lacquers with acrylic enamels because the costs of
the spray booth are offset by the significantly lower material costs for
acrylic enamels. For those small facilities that already own spray
booths, a switch to alternative topcoats would have little effect in terms
of cost. The slight cost savings of $300/yr incurred when solvent-borne
primers are replaced with waterborne primers shows that the costs for
application of both of these primers is comparable. The installation of a
solvent recovery systen generates a savings of $580/yr because the use of
solvents during equipment cleanup is reduced significantly (75 to
80 percent less). Replacing conventional air-atomizing spray guns with
HVLP spray equipment results in a savings of $l,300/yr. This option
assumes that lacquers would continue to be used but that less paint 1s
required due to the higher transfer efficiency (about 65 percent versus
about 35 percent).
7-6
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TABLE 7-3. COST OF AVAILABLE TECHNIQUES FOR REDUCING VOLATILE ORGANIC COMPOUND EMISSIONS FROM A SMALL
AUTOMOBILE REFINISHING FACILITYa
Raw Annual Ized
•aterlal cost. Capital raw Material
Reduction technique $/ partial job0 c cost, t cost, t/yr
Current practice 22.65 3.500 6.800
(baseline)
Replace lacquers with 13.39 13.500 4.000
acrylic enaiels
Replace lacquers with 21.41 13.500 6.400
urethanes
Replace solvent-borne 21.72 3.500 6.500
pr tiers with water borne
pr tiers
Replace conventional clear 21.47 13.500 6.400
coats with higher solids
clears
Install cleanup solvent 21.17 4.100 6.400
recovery systeas
Replace conventional air- 13.56 12,700 4.100
atoatzing spray guns with
hlgh-voluae. low-pressure
(HVLP) spray equipment
Annual! zed Total Cost VOC VOC reduction Increaental
equipment. annual ized (savings) froi emissions. froa baseline cost.
cost. t/yrd cost. $/yr baseline, $/yr tons/yr Tons/yr Percent I/ton VOC
560 7.400 KAe 1.27 NA NA NA
2.200 6.200 (1.200) 0.69 0.58 46 0
2.200 8.600 1.200 0.59 0.68 54 2.100
560 7.100 (300) 0.96 0.31 24 0
2.200 8.600 1.200 0.95 0.32 25 3.900
650 7.000 (400) 1.08 0.19 15 0
2.000 0.100 (1.300) 0.86 0.41 32 0
^Values (except raw Mterlal costs) have been rounded according to the rules of significant figures.
"Partial jobs are defined as being equivalent to coating a 10-ft' area.
'Based on typical basecoat. clearcoat systems.
"Values are based on an Interest rate of 9.5 percent (one point above the March 7. 1988. priae rate).
*NA • not applicable.
-------
CO
TABLE 7-4. COST OF AVAILABLE TECHNIQUES FOR REDUCING VOLATILE ORGANIC COMPOUND EMISSIONS FROM A MEDIUM
AUTOMOBILE REFINISHING FACILITY*
Raw Annualized
aaterial cost. Capital raw aaterlal
Reduction technique I/part tal job0 c cost. $ cost. $/yr
Current practice 18.27 57.000 21.000
(baseline)
Replace lacquers with 12.63 57.000 14.500
acrylic enaaels
Replace lacquers and 20.65 57.000 23.700
enaaels with urethanes
Replace solvent-borne 17.80 57.000 20.500
pr tiers with waterborne
pr tiers
Replace conventional clear 18.53 57.000 21.300
coats with higher solids
clears
Install solvent recovery 17.17 57. 600 f 19.700
systeas
Replace conventional air- 10.86 67.8009 12.500
atoaizing spray guns with
high-voluae. low-pressure
(HVLP) spray equipaent
Annualized Total Cost VOC VOC reduction Incremental
equipaent annualized (savings) froa ' eaissions. froa baseline cost.
cost. $/yr° cost, $/yr baseline. $/yr tons/yr Tons/yr Percent J/ton VOC
9,100 30.100 HA* 3.63 HA NA
9.100 23.600 (6.500) 2.27 1.36 37 0
9,100 32.800 2.700 1.89 1.73 48 1.600
9.100 29.600 (500) 2.73 0.90 25 0
9.100 30.400 300 2.82 0.81 22 370
9.200 28.900 (1,200) 3.08 0.55 15 0
10.800 23.300 (6.800) 2.46 1.17 32 0
^Values (except raw aaterlal costs) have been rounded according to the rules of significant figures.
"Partial jobs are defined as being equivalent to coating a 10-ft* area.
•.Based on typical basecoat. clearcoat systeas.
"Values are based on an interest rate of 9.S percent (one point above the March 7. 1988. p'rlae rate).
!NA • not applicable.
'Astuaes baseline capital cost plus an additional $600 for a solvent recovery systea.
°Assuaes $15.000 for HVLP spray equipaent, $50,000 for a spray booth, and $2,800 for a lining station.
-------
TABLE 7-5. COST OF AVAILABLE TECHNIQUES FOR REDUCING VOLATILE ORGANIC COMPOUND EMISSIONS FROM A VOLUME
AUTOMOBILE REFINISHING FACILITY*
Raw Annual ized
•atertal cost. Capital raw aaterial
Reduction technique S/partlat job0 c cost. S cost. J/yr
Current practice 13.33 1U.700 109.300
(baseline)
Replace lacquers and 19.39 114,700 159.000
enaaels with urethanes
Replace solvent-borne 13.17 114.700 108.000
pr leers with waterborne
pr leers
Replace conventional clear 15.21 1U.700 124.800
coats with higher solids
clears
Install solvent recovery 12.86 115.900 105.400
systeas
Replace conventional air- 7.62 122.200 62.400
^j atoalzlng spray guns with
1 high-voluae. low-pressure
10 (HVLP) spray equipment
Theraal Incineration 13.33 264.700 4 49. 000 f
Annuallzed Total Cost VOC VOC reduction Incremental
equlpaent. annual Ized (savings) fro* emissions. froa baseline cost.
cost. $/yrg cost. |/yr baseline. S/yr tons/yr Tons/yr Percent S/ton VOC
18.300 127.600 HAe 11.1 NA NA NA
18.300 177.300 49.700 9.1 2.0 18 24.900
18.300 126.300 (1.300) 8.1 3.0 27 0
18.300 143.000 15.400 10.4 0.7 7 22.000
18.500 123.900 (3.700) 9.5 1.6 15 0
19.500 81.900 (45.700) 6.0 5.1 46 0
42.000 491.000 363.000 3. 59 7.6 68 46.500
'Values (except raw aaterla) costs) have been rounded according to the rules of significant figures. Replacing lacquers with enanels was not considered because volune shops
.were assumed to use enaaels and urethanes only. .
"Partial jobs are defined as being equivalent to coating a 10-ft* area.
'Based on typical basecoat. clearcoat systeas.
"Values are based on an Interest rate of 9.5 percent (one point above the March 7. 1988. priae rate).
'HA > not applicable.
'Includes annual operating cost of S340.000.
9A$suae 98 percent control of spray booth eaissfons.
-------
The costs for the typical medium-sized facility were developed under
the assumption that both lacquers and enamels were used and that this
facility owns a spray booth. The capital cost of two sets of conventional
spray equipment and the cost of a spray booth were included in the
baseline capital cost. Replacing lacquers and enamels with urethanes and
replacing conventional clearcoats with higher solids clears result in
annualized costs above baseline at $2,700/yr and $300/yr, respectively.
This increase is due to higher costs for the urethane coatings. Replacing
lacquers with acrylic enamels again shows a significantly lower annualized
raw material cost that results in an annualized cost savings of
$6,500/yr. Replacing solvent-borne primers with waterbome primers
results in a cost savings of $500/yr; the overall difference in annualized
cost between the use of the two primers is relatively small and indicates
that the cost of using each primer is comparable. (Note that, for both the
small and the medium facilities, a slight cost savings is associated with
switching to waterborne primers.) As for the small facility, the
installation of a solvent recovery system and the use of HVLP spray
equipment Instead of conventional spray equipment at medium facilities
both show savings from baseline. These savings are $l,200/yr and
$6,800/yr, respectively, and result from reduced cleanup solvent
consumption (approximately 75 percent reduction) and reduced coating
consumption (about a 50 percent reduction in coating usage), respectively.
The costs for the typical volume facility assume- that enamels and
urethanes are used and that two spray booths and two mixing stations are
available. Therefore, replacing lacquers with enamels was not considered
as an option for this analysis. The capital cost of three sets of
conventional spray equipment, two spray booths, and two mixing stations,
were included in the baseline capital cost.
Replacing enamels with urethanes and replacing conventional
clearcoats with higher solids clears result in significant increases in
annualized costs above baseline—$49,700/yr and $15,400/yr, respec-
tively. Replacing solvent-borne primers with waterborne primers results
in a savings of $l,300/yr. The installation of solvent recovery systems
and the use of HVLP spray equipment both result in significant savings
from baseline. These savings are $3,700/yr and $45,700/yr, respectively,
7-10
-------
and are based upon reduced cleanup solvent consumption (approximately
75 percent) and reduced coating consumption (approximately 50 percent),
respectively.
The cost of control of spray booth emissions by thermal incineration
was estimated for the volume facility. The thermal incinerator was
assumed to achieve a 98 percent control of the spray booth emissions
(100 percent capture, 98 percent control efficiency). This control level
results in an overall VOC reduction of 68 percent. However, the cost of
control is high; the total annualized operating cost is $363,000 above
baseline. The cost of the auxiliary fuel (natural gas) is a significant
portion of the annual operating cost. The cost of controlling spray booth
emissions by carbon adsorption were not estimated during this study. A
recent study conducted for the State of New Jersey estimated the total
annualized operating cost of controlling a single spray booth by carbon
adsorption at $50,000/yr.9 Similarly, in a recent study, the State of New
York estimated the total annualized operating cost for a carbon adsorption
control system at $66,000/yr.8 (Note: These two studies estimated the
cost of control by.incineration at $160,000 and $43,000 per year, respec-
tively.) The wide variation in cost estimates for add-on controls
suggests that the assumptions used for specific applications should be
carefully considered.
Traditionally, the incremental cost effectiveness of a control
alternative is calculated by dividing the additional cost above baseline
by the VOC emission reduction below baseline level. The incremental costs
($ per unit of VOC reduction) may then be used to evaluate whether the
cost of achieving a unit reduction is reasonable. When the cost to
achieve an emission reduction results in a negative value (i.e., a cost
savings), the calculated cost-effectiveness value has no meaning because
there is no additional cost associated with achieving the emission
reduction. Several of the control alternatives presented in this study
result in a cost savings. The incremental cost for these alternatives are
reported as zero. The incremental costs of VOC reduction for the various
alternatives associated with the typical small, medium, and large
facilities are presented in Tables 7-3 through 7-5, respectively.
7-11
-------
It is apparent that, in each case, the use of HVLP spray equipment
Instead of conventional air spray guns and the installation of a solvent
recovery system result 1n a cost savings. Switching to acrylic enamels at
those facilities that use lacquers also will result 1n a cost savings.
The costs of switching from traditional primers to waterborne primers are
comparable. Cost Increases are associated with the other alternatives
presented.
7.4 REFERENCES FOR SECTION 7
1. Letter from R. Hick, DuPont, Wilmington, Delaware, to R. Blaszczak,
ESD/EPA. Research Triangle Park, North Carolina. February 8, 1988.
2. Attachment to letter from G. Ocampo, Sherwin-Williams, Cleveland,
Ohio, to R. Blaszczak, ESD/EPA. Research Triangle Park, North
Carolina. February 3, 1988.
3. Attachment to letter from D. Braun, BASF Corporation, Whitehouse,
Ohio, to R. Blaszczak, ESD/EPA. Research Triangle Park, North
Carolina. February 22, 1988.
4. Letter and attachments from R. Rondlnelli, The DeVllbiss Company,
Toledo, Ohio, to R. Blaszczak, ESD/EPA. Research Triangle Park,
North Carolina. February 12, 1988.
5. Letter and attachments from M. Bunnell, Can-Am Engineered Products,
Livonia, Michigan, to R. Blaszczak, ESD/EPA. Research Triangle Park,
North Carolina. December 29, 1987.
6. Product Bulletin from Herkules Equipment Corporation, Walled Lake,
Michigan. 1987.
7. Peters, M. A., and Tlmmerhaus, J. D. Plant Design and Economics for
Chemical Engineers, 2nd Edition. McGraw-Hill Book Company, New
York. 1968.
8. An Evaluation of Alternatives to Reduce Emissions From Automobile
Refinlshing 1n the New York Metropolitan Area. New York State
Department of Environmental Conservation. August 1987.
9. Radian Corporation, Austin, Texas. Economic Energy and Environmental
Impacts of Add-On VOS Controls on the Automobile Refim'shlng Industry
in New Jersey. August 31, 1987.
10. Telecon of conversation between R. Hick, DuPont, Wilmington,
Delaware, and M. Turner, Midwest Research Institute, Cary, North
Carolina. June 23, 1988.
7-12
-------
11. EAB Control Cost Manual (Third Edition), EPA 450/5-87-001A. U. S,
Environmental Protection Agency, ESO/EPA, February 1987.
7-13
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8.0 EXISTING REGULATIONS
8.1 INTRODUCTION
This section presents the current status of regulatory development
work by State and local air pollution control agencies to limit VOC
emissions from the automobile refinishing industry. The agencies
presented here are those participating in the reasonably available control
technology (RACT) clearinghouse project. The information presented in
this section is not intended to provide an exhaustive source of
information on regulatory development nationwide, but rather to give an
overview of State and local regulatory positions regarding emissions from
the automobile refinishing industry.
8.2 FEDERAL REGULATIONS
No regulations have been promulgated under the Clean Air Act
specifically to address emissions from automobile refinishing operations.
8.3 STATE AND LOCAL REGULATIONS
Twenty State and local agencies were contacted to provide an overview
of the current level of regulation being applied to the automobile
refinishing industry across the United States. A list of the State and
local agencies contacted 1s found in Section 8.4.
Of those agencies contacted, only the-States of New York and Texas
have adopted regulations that directly govern the automobile refinishing
industry. The State of Oregon regulates automobile refinishing under a
surface coating and refinishing regulation. The California Bay Area and
South Coast Air Quality Management Districts (BAAQMD and SCAQMD) and the
State of New Jersey are actively considering Imposing regulations on the
automobile refinishing industry. Currently, the remaining States
contacted have either no regulations governing automobile refinishing or
have general rules governing industrial sources that have emission rates
above a certain threshold level. States with threshold levels that would
likely impact some automobile refinishing shops include Connecticut
(maximum 8 Ib VOC/h, 40 Ib VOC/d), Delaware (maximum 5 Ib VOC/h, 40 Ib
VOC/d), the District of Columbia (maximum 40 Ib VOC/d), Georgia (maximum
3 Ib VOC/h, 15 Ib VOC/d), North Carolina (maximum 40 Ib VOC/d) and Rhode
Island (new source maximum 10 Ib VOC/h).
8-1
-------
The following sections briefly describe the regulatory activities in
New York, Texas, Oregon, New Jersey, and the California BAAQMD and
SCAQMD.
8.3.1 New York
In its revised State implementation plan (SIP), the State of New York
committed to investigate the feasibility of adopting a control program to
reduce VOC emissions from automobile refinishing operations.1
8.3.2 Texas
The Texas Air Control Board adopted specific regulations for the
automobile refinishing industry in 1987. Coatings used are limited to the
following maximum VOC concentrations: primers, 2.1 Ib VOC/gal coating;
acrylic lacquers, 6.2 Ib VOC/gal coating; acrylic enamels, 5.2 Ib VOC/gal
coating; alkyd enamels, 5.0 Ib VOC/gal coating; clearcoat, 5.2 Ib VOC/gal
coating. In addition, recycling of cleanup solvents is required.2
8.3.3 Oregon
The Oregon Department of Environmental Quality regulates automobile
refinishing operations under a surface coating and refinishing regula-
tion. Shops that process less than 35 vehicles per day are considered to
emit less than 40 tons VOC per year and are exempt from regulation.
Nonexeapt shops must install control equipment. The Portland
metropolitan area is an ozone nonattainment area.
8.3.4 New Jersey
The New Jersey Department of Environmental Protection, Division of
Environmental Quality, included in its revised SIP a commitment to
regulate the automobile refinishing industry.** It is currently studying
this industry and expects to adopt a regulation within the next year.
8.3.5 California
8.3.5.1 Bay Area Air Quality Management District. The BAAQMD is
actively considering imposing regulations on automobile refinishers. A
questionnaire has been distributed to approximately 2,500 facilities under
the BAAQMD jurisdiction, and the responses are being evaluated. No
regulatory decision had been made at the time of this writing.
8.3.5.2 South Coast Air Quality Management District.6*7 The SCAQMD has
proposed Rule 1151 that would require the use of equipment that can
achieve a 65 percent transfer efficiency at a pressure of 10 ps1 or less
8-2
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(i.e., HVLP, electrostatic) and would limit the amount of VOC allowed in
various automobile coatings used in both coating new vehicles and
refinishing vehicles. These VOC limitations would be implemented in two
phases. The first phase would take effect on January 1, 1990, and would
set the following VOC limits for coatings used on passenger cars, light-
duty trucks, medium-duty vehicles, and motorcycles: pretreatment and
precoat operations, 6.7 Ib VOC/gal coating; primer, 2.1 Ib VOC/gal
coating; acrylic enamel, 5.2 Ib VOC/gal coating; alkyd enamel, 4.9 Ib
VOC/gal coating; polyurethane enamel, 5.2 Ib VOC/gal coating; and lacquer,
6.2 Ib/gal coating. The second phase would take effect on July 1, 1991,
and would apply to 1992 and subsequent model year vehicles and complete
(full body) paint jobs regardless of model year. These second-phase VOC
limitations are identical to the first-phase limitations for pretreatment,
precoat, and primers but set a significantly lower VOC limit of 3.5 Ib
VOC/gal coating for all topcoats regardless of their formulation. A
public hearing to consider adoption of Proposed Rule 1151 is scheduled for
July 8, 1988.
8.4 AGENCIES CONTACTED
The following State and local agencies were contacted to provide an
overview of the current level of regulation being applied to the
automobile refinishing industry in the U.S.:
Alaska Illinois
Arkansas Kentucky
California Maine
Bay Area Air Quality Management District Maryland
South Coast Air Quality Management District Massachusetts
Colorado North Carolina
Connecticut Oregon
Delaware Pennsylvania
Washington, D.C. Rhode Island
Florida South Carolina
Georgia
8.5 REFERENCES FOR SECTION 8
1. New York State Department of Environmental Conservation, Albany, New
York. An Evaluation of Alternatives to Reduce Emissions from
Automobile Refinishing in the New York Metropolitan Area.
August 1987.
8-3
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2. Texas Air Control Board, Austin, Texas. Regulation V, Chapter 115
Volatile Organic Compounds, revision 115.191 (b) (8)(D), Emission
Limitations. 1988.
3. Telecon of conversation between C. Ayer, Oregon Department of
Environmental Quality, Portland, Oregon, and J. Obremski, Midwest
Research Institute, Gary, North Carolina. December 8, 1987.
4. Radian Corporation, Austin, Texas. Economic, Energy, and
Environmental Impacts of Add-On VOS Controls on the Automotive
Refinishing Industry in New Jersey. August 31, 1987.
5. Telecon of conversation between J. Guthrie, California Bay Area Air
Quality Management District, San Francisco, California, and
M. Mclaughlin, MRI, Gary, North Carolina. January 15, 1988.
6. Telecon of conversation between B. Wallerstein, California South Coast
Air Quality Management District, El Monte, California, and M. Turner,
Midwest Research Institute, Gary, North Carolina. June 23, 1988.
7. Correspondence from B. Wallerstein, California South Coast Air Quality
Management District, El Monte, California, to R. Blaszczak, U. S.
Environmental Protection Agency, Research Triangle Park, North
Carolina. May 16, 1988.
8-4
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9.0 COMPLIANCE EVALUATION CONSIDERATIONS
Several available techniques for reducing VOC emissions have been
presented in this document; the techniques utilize different approaches
for reducing VOC, including (a) reducing the VOC content of the coatings,
(b) employing equipment modifications to improve transfer efficiency and
reduce coating usage, and (c) employing work practice modifications such
as solvent recycling and recovery to reduce solvent emissions during
cleanup operations.
Section 8 presented a summary of current regulations for VOC
emissions from the auto refinishing industry. The current regulations
fall into four categories: (1) regulation of coating VOC content (e.g.,
SCAQMD, Texas); (2) emission limits in terms of pounds per hour or tons
per day (e.g., Colorado, Connecticut, Delaware); (3) performance standards
(e.g., 65 percent transfer efficiency, SCAQMD); and (4) equipment/work
practice standards (e.g., required recycling of cleanup solvents, Texas).
The reduction technique chosen, as well as the type of regulation
written, will have an impact on how compliance can be determined. The
available techniques and factors to be considered in determining
.compliance for the techniques are discussed in this section. Table 9-1
summarizes several compliance evaluation techniques and their
applicability to the available reduction techniques. The compliance
evaluation techniques that are applicable include recordkeeping, testing
the VOC content of coatings, inspections, emission testing, and equipment
testing.
Ultimately, recordkeeping is the most universal approach for
evaluating compliance with VOC emissions regulations. This is especially
true if a regulation is written in terms of emission rate (e.g., Ib/day)
without regard to the techniques employed for achieving the reduced
emission limit. In this case, accurate records on solvent and coating
usage, combined with their respective VOC contents, will provide the data
necessary to calculate emission rates. The minimum recordkeeping should
include the following information for properly evaluating compliance with
a VOC emissions standard:
9-1
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TABLE 9-1. APPLICABILITY OF COMPLIANCE EVALUATION TECHNIQUES
Alternative Coating Emission Equipment
control techniques Recordkeeping testing Inspections testing testing
Reduced VOC cleaners x x x
Improved transfer efficiency x x x
Lover VOC coatings (primers x x x
and topcoats)
Solvent recovery during x x
cleanup
Add-on control x x x
9-2
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1. The volume of each type of coating used.
2. The volume of thinners and reducers used.
3. The volume of vehicle preparation/equipment cleanup solvents
used.
4. The VOC content of each coating, thinner/reducer, and vehicle
preparation equipment cleaning solvent used. (This information can
usually be obtained from the manufacturer's material safety data sheet for
the product.)
5. The number and type of jobs completed. Daily records are
recommended.
Note that recordkeeping of solvent/coating usage would not be
directly applicable as a compliance evaluation technique for a regulation
which specifies add-on controls or a specific transfer efficiency.
Testing the solvents and coatings to determine their VOC content is a
compliance evaluation technique that can be used to augment record-
keeping. Testing of the materials is especially applicable to the cases
where a regulation explicitly limits the VOC content of the coatings. In
such cases, specific criteria (e.g., test methods and frequency of
testing) for determining compliance should be established in conjunction
with the regulation.
Emission testing has very limited applicability as a compliance tool
due to the fugitive (unconflned) nature of the emissions from this
industry. Emission testing only will be applicable 1n cases where an add-
on control device is being used and where a control efficiency is
stipulated. In such cases, emission testing of the control device inlet
and outlet air streams will provide data on the control device efficiency
for removing VOC's from the captured air stream.
Equipment testing is a compliance technique that can be used if
specific equipment performance standards have been included in a
regulation, for example, if a specific transfer efficiency is
stipulated. However, this technique is limited in its field
application. Field evaluation of spray equipment for the automobile
reflnishing Industry is impractical due to the expense involved and the
variability of shop conditions. A more straightforward approach is to
require evaluation of specific equipment by the manufacturer or by an
9-3
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independent laboratory under controlled conditions to determine if the
equipment meets specific performance criteria. Compliance with the
regulation would be based on use of equipment that has been demonstrated
to meet the performance criteria.
Inspections are a compliance tool that augment all other compliance
evaluation techniques and are applicable in all cases. Inspections can be
used to evaluate (a) records and recordkeeping procedures; (b) types and
quantities of solvents used; (c) operating conditions and use of required
special equipment (e.g., cleanup solvent recovery systems, high transfer
efficiency spray systems, add-on controls); and (d) general work
practices.
Inspections are a valuable part of any compliance program since they
provide the opportunity for a "hands-on" evaluation of facility
operation. This enables the inspector to evaluate other information (such
as records of solvent/coating usage) available for determining compliance.
9-4
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10.0 GLOSSARY OF COATING TERMS1'2
Acrylic: A thermoplastic resin made from the polymerization of acrylic
derivatives, chiefly from the esters of acrylic acid and related
compounds, and characterized by excellent durability and color
retention.
Additives: Chemical substances added to a finish in small quantities to
impart or improve desirable properties such as corrosion resistance,
durability, or curing rate.
Alkyd: A thermosetting synthetic resin made from the combination of an
alcohol, an acid, and an oil. While properties vary widely with
ingredients, alkyd enamels are generally not as durable as acrylic
enamels.
Basecoat: A color coat requiring a clear final coat.
Body filler: A thick plastic material which is used to fill small dents.
Build: The amount of paint film deposited, specifically the film
thickness in mils.
Cast: Describes where a color lies in relation to others. Also known as
hue.
Clearcoat: A transparent coating over the color coat (basecoat) in
basecoat/clearcoat systems.
Color coat: The paint layer that contains pigment; may constitute the
topcoat by itself or serve as the basecoat portion of a
basecoat/clearcoat system.
Compatibility: The ability of one coating to adhere properly to another.
Compounding: The action of using an abrasive material (i.e., compounding
agent) to smooth and Improve the gloss of lacquer topcoats. Also
referred to as polishing.
Curing: The chemical reaction that takes place in the drying of
nonlacquer coatings.
Degreasing: Cleaning a substrate by removing greases, oils, and other
surface contaminants. Generally performed as part of vehicle
preparation.
Drying: The change from a liquid to a solid that occurs after the paint
is deposited on a surface. This change includes evaporation of the
solvent and any chemical curing that might occur.
Dry spray: Spraying under-reduced coatings. In metallic finishes, this
traps the metallic particles near the surface, causing a highly metallic
color effect.
10-1
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Electrostatic spray: A method of applying a spray coating in which
opposite electrical charges are applied to the substrate and the
coating. The coating is attracted to the object by the electrostatic
potential between them.
Emulsion: A two-phase liquid system in which small droplets of one liquid
are uniformly dispersed throughout the second.
Enamel: A coating that cures by chemical cross-linking of its base
resin. Enamels can be readily distinguished from lacquers because
enamels are not resoluble in their original solvent.
Evaporation: The change from a liquid to a gas; the means through which
solvents leave a coating film as it dries.
Face: The color of a finish when viewed perpendicular to the surface.
Filler: A heavily plgmented coating used to fill small Imperfections such
as scratches in a substrate.
Film: A very thin continuous sheet of material.
Flash: The initial stage of drying when some of the solvent evaporates,
dulling the surface from a high gloss to a normal gloss.
Flat: Lacking in gloss.
Flocculation: Formation of clusters of pigment particles.
Flooding: The phenomenon that occurs when metallic particles settle in
the paint film, causing a strong pigment color effect.
Flop: The color of a finish when viewed from an acute angle.
Flow: The leveling characteristics of a wet paint film.
Gelation: The development of Insoluble polymers in paints. Normally
irreversible.
Gloss: A property of paints and enamels which can be characterized by
measuring the specular reflectance of the film using ASTM test D 523-67
(1972) Test for Specular Gloss. The 60-degree specular gloss test is
used for all except flat paints. A measurement of 65 or more
characterizes the material as "gloss." Semigloss paints are those with
readings between about 30 to 65; "flats" when tested at an 85 degree
angle have readings below 15.
Hardener: An additive designed to promote a faster cure of an enamel
finish.
10-2
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Hardness: That quality of a dry paint film that provides resistance to
surface damage.
Haze: The development of a cloud in a film or a clear liquid.
Hiding: The degree to which a paint obscures the surface to which it is
applied.
Hold out: The ability of a coating to prevent the topcoat from sinking
1n.
Inhibitor: A paint additive which slows or prevents some process (e.g.,
corrosion inhibitor).
Lacquer: A coating which dries primarily by solvent evaporation and,
hence, is resoluble in its original solvent.
Leafing: The orientation of metal flake pigments in a paint film which
results 1n a bright metal appearance and a concentration of the
particles at the surface of the film.
Lifting: The attack by the solvent in a coating on the previously applied
coating, which results in distortion or wrinkling of the new coating.
Lightness: The amount of white or black in a given color, measured by the
amount of light reflected by a surface. Also called value.
Metal conditioner: An acidic metal cleaner which removes rust and
corrosion from bare metal, etches the surface for improved coating
adhesion, and forms a film to Inhibit further corrosion.
Metallic paint: Paint containing tiny flecks of aluminum or other metal
often used for painting automobiles because of the attractive appearance
of the paint.
MEK: Methyl ethyl ketone. Used as a fast-evaporating solvent, primarily
with lacquers.
Micas: Finishes which contain mica flakes (aluminum silicate) 1n addition
to the pigment.
MIBK: Methyl isobutyl ketone. Used as a medium-evaporating solvent.
M1st coat: A coat of rich, slow-evaporating thinner with little color
added. Also called a blend coat.
Mottling: A film defect appearing as blotches or surface imperfections.
Occurs in metal!ics when the flakes float together.
Orange peel: A paint surface appearance, characterized by small pits,
resembling the surface texture of an orange. Depending on the product,
this may be desirable (appliances) or highly undesirable
(automobiles).
10-3
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Overall repainting: Repainting the entire vehicle.
Overspray: That solids portion of a coating sprayed from a spray
applicator which fails to adhere to the part being sprayed. (Applied
solids plus overspray solids equal total coating solids delivered by the
spray application system.)
P/B: The pigment-to-binder ratio. The ratio of the weight of pigment to
the weight of binder in a coating.
Paint remover: A chemical that breaks down an old finish by liquifying
it.
Panel repair: A repair in which a complete section (e.g., hood, door) is
repainted.
Particle size: The size of the pigment particles in a coating. Measured
in mils (l/l,000th of an inch).
Pigment: A finely ground insoluble powder dispersed in a coating to give
a characteristic color.
Plastidzer: A substance added to a polymer composition to soften and add
flexibility to the product.
Polyurethane: Urethane resins are primarily produced by reacting
isocyanates with carboxylie compounds. They may be sold as one- or two-
component systems, and are characterized by high resistance to stains,
water, and abrasion.
Primer: First layer of coating applied to a surface.
Primer-sealer: A primer that improves adhesion of the topcoats and that
seals old painted surfaces.
Primer-surfacer: A coating, usually applied over a thin primer, which
gives "body" to the surface, fills Irregularities, and, unlike the
primer, 1s Intentionally thick enough to permit sanding without cutting
through the bare metal. A topcoat is applied over a primer-surfacer.
Reduce: To lower the viscosity of a coating by adding solvent.
Reducing solvent: A solvent added to dilute a coating usually for the
purpose of lowering the coating's viscosity.
Retarder: A solvent added to a coating to reduce the evaporation rate.
Rubbing compounds: Abrasives that smooth and polish the coating film.
Used primarily with lacquer coatings.
Runs: Excessive vertical flow resulting in poor adhesion.
10-4
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Sagging: Sprayed material that fails to adhere properly to the surface.
Sandscratch swelling: A painting problem characterized by a swelling of
sandscratches in the old surface caused by solvents in the new coat.
Sealer: A material that protects the substrate from subsequent coatings
or protects coatings from something in the substrate.
Semi-gloss: An intermediate gloss between high and low gloss.
Sheen: The gloss or flatness of a coating film when viewed at a low
angle.
Show through: Flaws in the primer which are visible through the topcoat.
Solids: The percentage, on either a weight or volume basis, of solid
(i.e., nonsolvent) material in a coating.
Spot repair: A type of refinish repair job in which a section of vehicle
smaller than a full panel is repaired. This is the most frequent
repair.
Spray booth: An enclosed, ventilated area used for spray painting.
Spray gun: A tool for directing atomized coating at the surface to be
painted. Atomlzation may be by high-pressure air, by high-pressure
steam, by high fluid pressure, by electrical means (electrostatic
process), or by high-volume, low-pressure (HVLP) air.
Stabilizer: A chemical compound added to a coating to prevent
degradation.
Strength: The opacity and/or tinting power of a pigment. This is a
measure of the ability of a pigment to color.
Substrate: The surface to which a coating is applied.
Surfacer: A coating applied over a primer to provide a uniform surface
thick enough to permit some sanding before application of a topcoat.
Surfacer 1s also known as primer-surfacer.
Tack: The stickiness of a coating film. The time required for a coating
to become tack-free at ambient.conditions is a common measure of drying
speed.
Thinner: A liquid that is used to reduce the viscosity of a coating and
that will evaporate before or during the cure of a film.
Tint: To add color to another color.
Tinting strength: The ability of a pigment to change the color of a
coating to which 1t is added.
10-5
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Toluene: A fast-evaporating solvent, frequently used.
Topcoat: The last coat applied in a coating system.
Transfer efficiency: The ratio of the amount of coating solids deposited
onto the surface of the coated part to the total amount of coating
sol Ids used.
Undercoat: A first coat; primer, sealer, or surfacer. Should not be
confused with the "undercoat" applied underneath new vehicles for rust
protection.
Undertone: The color of a pigment that becomes visible when that pigment
is mixed with a white pigment.
Weathering: The change 1n a paint film over time.
Xylene: A widely used solvent with a medium evaporation rate.
Yellowing: A yellow discoloration of a coating film.
REFERENCES FOR SECTION 10
1. Glossary for A1r Pollution Control of Industrial Coating Operations,
Second Edition, EPA-450/3-83-013R, U. S. Environmental Protection
Agency, Research Triangle Park, North Carolina. December 1983.
2. OuPont Auto Reflnishing Handbook, E. I. du Pont de Nemours & Company,
Inc., Wilmington, Delaware. 1987.
10-6
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APPENDIX A.
METHODOLOGY FOR DETERMINING AUTOMOBILE REFINISHING SHOP SIZE CATEGORIES,
THE NUMBER OF AUTOMOBILE REFINISHING JOBS PER SHOP, AND
THE TYPES AND AMOUNTS OF COATINGS USED IN EACH SHOP
-------
APPENDIX A. METHODOLOGY FOR DETERMINING AUTOMOBILE REFINISHING SHOP
SIZE CATEGORIES, THE NUMBER OF AUTOMOBILE REFINISHING JOBS PER SHOP,
AND THE TYPES AND AMOUNTS OF COATINGS USED IN EACH SHOP
In order to develop a categorization scheme for automobile
reflnlshlng shops, 1t was necessary to have a good understanding of the
Industry Including trends 1n types of repairs, types of coatings used 1n
the Industry, the level of sophistication of the shops, and the number of
jobs performed on a weekly basis. A source of valuable information in
developing the categorization scheme was the Body Shop Business Industry
Profile, 1987. This publication provided its own categorization scheme
that Included the following information for six categories: sales volume,
average number of jobs per shop, and percent of total number of shops per
category. The first four columns of Table A-l present this information.
The remainder of the table reflects some manipulation of the data based on
the 83,100 automobile refinishing shops nationwide. This number was
multiplied by the appropriate percentage for each category to obtain the
total number of shops per category. The total number of jobs per category
was then calculated by multiplying the number of shops per category by the
average number of jobs per shop. Categories A and B were combined to form
the small shop category; categories C, D, and E were combined to form the
medium shop category; and category F formed the volume shop category.
This categorization was developed because: three model shops were
desired; the volume shop clearly stood out on its own having an average of
28.4 jobs per shop; categories C, D, and E lay relatively close to the
average of 13.2 jobs per shop and combined to produce a weighted average
of 14 jobs per shop (near the average of all shops); and categories A and
B combined to produce a weighted average of six jobs per shop.
The coatings used in the automobile refinishing industry vary
significantly by shop size and by the availability of a spray booth. A
spray booth prevents deposition of windblown dust particles and dirt on
the freshly painted surface of the slower drying enamel and urethane
coatings. Lacquer coatings, due to their relatively fast drying time, do
not require a spray booth to produce a satisfactory finish. The following
assumptions were made in order to simplify the analysis. It was assumed
A-l
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that small shops do not own a spray booth and, therefore, spray lacquers
exclusively. The medium shops were assumed to own a spray booth and were,
therefore, able to spray enamels in addition to lacquers. The volume
shops were assumed to own two spray booths and were able to spray enamels
and the more sophisticated urethane coatings.
In a conversation between Mr. Raymond Conner of the National Paint
and Coatings Association and Mr. Mark Turner of Midwest Research
Institute, Mr. Conner provided an estimate of 36,000,000 gal of coatings
sold in the United States in 1983. This estimate was made up of
13,000,000 gal of primer and 23,000,000 gal of topcoat. The following
analysis shows how paint usage was allocated among the model shops
developed above.
1. Find the coating usage by coating type:
lacquers = 34 percent of coatings sold
enamels = 54 percent of coatings sold
urethanes = 12 percent of coatings sold
To account for any increase in coating usage, 40,000,000 gal of
coating were assumed to be sold 1n 1987. Therefore:
lacquers = (0.34)(40,000,000) = 13,600,000
enamels = (0.54)(40,000,000) = 21,600,000
urethanes = (0.12)(40,000,000) = 4,800,000
2. Find the amount of lacquer coatings used at small shops:
A small shop will use lacquers exclusively on the six partial jobs
performed.
For a partial lacquer job, 0.3518 gal coating are used.
(0.3518 gal/job)(6 jobs/week shop)(50 weeks/yr)(33,200 shops)
= 3,503,928 gal lacquer/yr
= 3,504,000 gal lacquer/yr
3. Find the number of lacquer partial jobs performed at medium
shops;
Total lacquer coating usage = 13,600,000
Small shop lacquer coating usage = 3,504,000
.*. medium shop lacquer coating usage = 10,096,000 gal/yr
A-2
-------
(10,096,000 gal/yr)(job/0.3518 gal)(yr/50 weeks)(41,300 shops)
= 13.9 jobs/week-shop
= 14 jobs/week-shop (lacquer partial jobs per week at medium
shops)
.*. 1 full job and 4 partial lacquer jobs (5 total jobs) are
performed (1 full job = 10 partial jobs)
4. Find the number of enamel partial jobs performed at medium shops:
From Table A-l, 14 jobs are performed at each medium shop. If 5 of
the 14 are lacquer jobs (1 full and 4 partial), then 9 enamel jobs are
performed at each medium shop. Typically, medium shops perform three to
four full jobs per month. Therefore, since one full lacquer job is
assumed to be performed at medium shops each week, all nine enamel jobs
are assumed to be partial jobs.
For a partial enamel job, 0.3004 gal coating are used.
(0.3004 gal/job)(9 jobs/week-shop)(50 weeks/yr)(41,300 shops)
= 5,582,934 gal enamel/yr
= 5,583,000 gal enamel/yr
5. Find the number of urethane jobs (partial and .full) performed at
volume shops:
For a partial urethane job, 0.2828 gal of coating are used.
Additionally, 4,800,000 gal/yr of urethane are used.
(4,800,000 gal/yr)(job/0.2828 gal)(yr/50 weeks)(8,600 shops)
=39.5 jobs/week-shop
- 40 jobs/week-shop (urethane partial jobs per week at volume
shops)
Although urethanes are gaining in popularity, most urethane paint
jobs are full body paint jobs. Therefore, it was assumed that four full
urethane jobs are performed per week at volume shops.
6. Find the number of enamel jobs (partial and full) performed at
volume shops;
Total enamel coating usage = 21,600,000
Medium shop enamel coating usage = 5,583,000
.'. Volume shop enamel coating usage = 16,017,000 gal/yr
A-3
-------
(16,017,000 gal/yr)(job/0.3004 gal)(yr/50 weeks)(8,600 shops)
= 124 jobs/week-shop (enamel partial jobs per week at volume
shops)
Because 4 full urethane jobs are performed, we know that there are
24 enamel jobs. However, 124 partial jobs translate into 1,240 ft2.
Therefore, the breakdown is as follows:
11 full enamel jobs (1,100 ft2)and 14 partial enamel jobs (140 ft2)
(25 total enamel jobs; and 1,240 ft2 area coated)
Although this breakdown gives one more job than the total 28 jobs for this
category, it is not expected to have a significant impact on emission
estimates. The breakdown will have no impact on emissions per job, cost
per job, or expected emission reductions.
A-4
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APPENDIX B.
TYPICAL COATING PARAMETERS FOR VOC CALCULATIONS
(CALCULATIONS FOR TABLE 4-2)
-------
TYPICAL COATING PARAMETERS FOR VOC CALCULATIONS
(CALCULATION FOR TABLE 4-2)
Percent coating solids, as sprayed, is calculated as follows:
"as Vt/100 percent
where
Gas = coating solids, volume %, as sprayed
Gs = coating solids, as sold, in gallons solids/gallon of coating
sold
Vt = total coating volume, as sprayed (volume of coating as sold
plus volume of reducer added), gallons
The gallons of coating solids applied per week are calculated as follows:
G _ (N)m(AH7.4805 gal/ft3)
^a ~ 12,000 rails/ft
where
Ga » gallons of coating solids applied per week
T » final coating thickness in rails
A = surface area being coated in ft (assumes 10 ft for partial
job)
N = number of partial jobs performed per week (one total job
= 10 partial jobs)
The gallons of coating solids used per week are calculated as follows:
G - Ga
u ~ TE/100 percent
where
GU = coating solids used in gallons of solids per week
Ga = coating solids applied in gallons of solids per week
TE = transfer efficiency in percent (baseline TE = 35 percent)
B-l
-------
Coating volume in gallons per week as sprayed, 1s calculated as follows:
G..
as Gae/100 percent
as
where
Vas = volume of the coating sprayed 1n gallons per week
The VOC emissions calculations from Table 4-4 for coatings as pounds per
day are calculated as follows:
Vas (CVOC}
VOC. = as VUL
't 5 days/week
where
= total dally VOC emissions for a particular coating type (i.e.,
primer, basecoat, or clearcoat) in pounds per day
= V^C content of the coating type (i.e., primer, basecoat, or
clearcoat) as sprayed in pounds per gallon
The volume of solvent used for cleanup and surface preparation is
calculated as follows:
a. V°C*
6.95 Ib/gal
where
J = the volume of solvent in gallons per day
VOCS = the solvent VOC emissions from cleanup and surface preparation
in pounds per day
The VOC emissions from the use of cleanup and surface preparation solvents
are estimated as follows:
vocs = (voctp+voctb+voctc)xf
B-2
-------
where
VOCtp = total daily VOC emissions from application of primer in
pounds per day
VOCtjj = total dally VOC emissions from application of basecoat 1n
pounds per day
VOC^j. = total dally VOC emissions from application of clearcoat in
pounds per day
The 30/70 ratio is based on an estimate that emissions from the use of
cleanup solvents account for 30 percent of the total VOC emissions.
Therefore, if:
VOCg = total daily VOC emissions from the facility in pounds per day
VOCS = total daily VOC emissions from cleanup and preparation
solvents in pounds per-day =0.3 VOCg
VOCC = total dally VOC emissions from coatings as sprayed in pounds
per day * 0.7 VOCg
VOCC = VOCj-p+VOCttj+VOCtj.; and
VOCD = VOCC+VOCS
then:
vocs = vocc(|§)
The total emissions, in tons/yr, for each option are calculated as
follows:
VOC (83,100)(250d/yr)
VOC.. = — wa
2,000 Ib/ton
where
VOCy = the total VOC emissions in tons per year
VOCwa = the weighted average VOC emissions per shop in pounds per
day
83,100 * the total number of automobile refinishing shops nationwide.
B-3
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[Note: The weighted average VOC emissions per shop was determined as
follows: VOCtp, VOCtb, VOCtc, and VOCS were summed to obtain VOC0 for
each shop category. Then, VOCg for each category was multiplied by the
number of shops in the appropriate category to obtain the total emissions
in each category. The emissions total from each category was then summed
to obtain the total daily emissions for all shops. This total daily
emissions was then divided by the total number of shops to obtain the
weighted average VOC emissions per shop.]
Reference for Appendix B
1. Letter from R. Hick, DuPont, Wilmington, Delaware, to R. Blaszczak,
ESD/EPA. Research Triangle Park, North Carolina. February 8, 1988.
B-4
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APPENDIX C.
CALCULATION OF THERMAL INCINERATION ADD-ON CONTROL COSTS
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APPENDIX C. CALCULATION OF THERMAL INCINERATION ADD-ON CONTROL COSTS
Table C-l summarizes the costs for the thermal incinerator. The
costs were calculated according to the procedures in the U. S.
Environmental Protection Agency, EAB Control Cost Manual (3rd Edition),
EPA 450/5-87-001A, February 1987. The following assumptions were used:
1. For volume facility, two spray booths must be controlled;
2. Each downdraft spray booth has a volumetric flow rate of
12,000 scfm, based upon the following spray booth dimensions: 14 ft wide,
25 ft long, and 9 ft high. Average air velocity is 35 ft/min.
14 ftx25 ftx35 ft/min = 12,250 ft3/min
3. The incinerator operates at 1600°F, has no heat recovery, and
operates on natural gas;
4. The spray booth off-gas has a VOC concentration of less than
100 ppm, is at 70°F, and has no heating value; and
5. The total capital investment costs, including installation costs,
were estimated as 1.5 times the purchased equipment costs.
Calculations
1. Calculate auxiliary fuel requirement:
Fuel used, ft3/ft3 waste gas:
Qs LI Cp AT5-Cp2AT2-h.
Q 2h3-l.lCp5AT5
where:
Q3 = auxiliary fuel flow rate, scfm
Q2 = waste gas flow rate, scfm
C = mean heat capacity of flue gas for temperature interval AT5,
5 reference temperature (70°F) to combustion temperature
AT5 = Temperature differential from reference (70°F) to outlet of
combustion chamber
C = mean heat capacity of waste gas for temperature interval AT2,
2 reference temperature (70°F) to combustion chamber inlet
AT2 * temperature differential from reference (70°F) to combustion
chamber inlet
C-l
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TABLE C-l. THERMAL INCINERATION COSTS
Cost
Capital costs
Purchased equipment cost 100,000
Total capital investment (l.Sxpurchased equipment) 150,000
Operating costs
Direct costs:
Auxiliary fuel 324,000
Electricity 2,000
Operating labor 1,500
Maintenance labor 1,500
Materials 1,500
Supervisory labor 250
Indirect costs:
Overhead (60 percent labor and materials) 2,850
G&A (4 percent total capital investment) 6,000
339,600
C-2
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ht = waste gas heat content, Btu/scf
h3 = lower heating value of fuel, Btu/scf
Q3 (1.1)(0.0194)-0-0
24,000 " 900-(1.1)(0.0194)
Q3 = 903 scfm
2. Determine cost of Incinerator:
Total gas flow through incinerator is equivalent to waste gas
(24,000 scfm) plus auxiliary fuel (900 scfm) = 25,000 scfm.
From Figure 3-3, EAB Control Cost Manual, the purchase equipment cost
is $100,000.
3. Calculate total capital investment:
The EAB Control Cost Manual indicates that installation costs can
vary from 25 percent to 300 percent of the purchased equipment cost. A
value of 50 percent was chosen. The capital investment cost is 1.5 times
the purchased equipment cost.
4. Calculate auxiliary fuel cost:
Natural gas cost = 900 ft3/minx60 min/hx2,000 h/yrx$3.00/1,000 ft3
= $324,000
5. Calculate electrical costs:
r (0.746) (QHAPUSHQ)P
LE " 6,356 n
where
G£ * cost of electricity
Q = gas flow rate, acfm
AP = pressure drop through system, in H20
S * specific gravity of gas
0 = operating factor, h/yr
P = price of electricity
n = fan and motor efficiency
r - (0.746H24.000H4m) (2,000) (0.05) _ $1 fl?7
CE " 6,356 (0.60) " 51'877
C-3
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6. Estimate operating labor:
0.5 h/dx250 dx!2/$/h = $1,500
7. Estimate maintenance labor:
Same as operating labor
8. Estimate maintenance materials:
Same as maintenance labor
9. Estimate supervisory labor:
Fifteen percent of operating labor = (0.15)(1,500) = $225
10. Estimate overhead costs:
Estimate is 60 percent of labor and materials
Overhead = (0.60)(1,500+1,500+1,500+225) = $2,835
11. Estimate taxes, Insurance, etc. (G&A):
Estimate used 1s 4 percent of total capital investment
G&A = (0.04) (150,000) =< $6,000
C-4
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
EPA 450/3-88-009
3. RECIPIENT'S ACCESSION NO.
4. TITLE AND SUBTITLE
5. REPORT DATE
October 1388
Reduction of Volatile Organic Compounds Emissions
in Automobile Refinishing
6. PERFORMING ORGANIZATION CODE
, AUTHOR(S)
Athey, Hester, Mclaughlin,
Neulicht, Turner
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Midwest Research Institute
401 Harrison Oaks Boulevard, Suite 350
Gary, North Carolina 27513
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
68-02-3817
12. SPONSORING AGENCY NAME AND ADDRESS
U. S. Environmental Protection Agency
Emission Standards Division
Office of Air Quality Planning and Standards
Research Triangle Park, North Carolina 27711
13. TYPE OF REPORT AND PERIOD COVERED
14. SPONSORING AGENCY CODE
15. SUPPLEMENTARY NOTES
ESD Work Assignment Manager:
Robert Blaszczak (MD-13) (919) 541-5406
16. ABSTRACT
Automobile refinlshlng (repainting) is a source of volatile organic compound (VOC) emissions. This
study was conducted to evaluate available techniques that can be used to reduce VOC emissions from this
source. This document provides information on the steps involved in the refinishing process which result in
emissions, available emission reduction techniques, VOC emission levels, VOC emission reductions, and costs
associated with the reduction techniques. Techniques investigated include: (1) reduced-VOC cleaners,
(2) replacement of lacquers with enamels, (3) replacement of enamels with poIyurethanes, (4) replacement of
solvent borne primers with waterborne primers, (5) replacement of conventional clearcoats with highei—solids
clearcoats, (6) installation of cleanup solvent recovery systems, (7) replacement of conventional spray guns
with higher transfer efficiency equipment, and (8) add-on controls
The primary conclusions from the study are: (1) the use of available techniques could result in VOC
emission reductions ranging from 3 percent to 50 percent of the current estimated baseline emissions from
typical refinishing shops; and (2) the annual ized costs for many of the available techniques are less than
the cost of current practices.
7.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lOENTIFIERS/OPEN ENDED TERMS 0. COSATI Field/Croup
Automobile Refinishing
Volatile Organic Compound
Emissions
VOC's
DISTRIBUTION STATEMENT
Release Unlimited
19. SECURITY CLASS /ThisReport)
21. NO. OF PAGES
20. SECURITY CLASS fThis page/
22. PRICE
EPA Form 2220-1 (R«v. 4-77) PREVIOUS EDITION is OBSOLETE
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