United States Office of Air Quality EPA-453/D-95-005a
Environmental Protection Planning and Standards August 1995
Agency Research Triangle Park NC 27711
Air
<& EPA Volatile Organic Compound
Emissions from Automobile
Refinishing -- Background
Information for Proposed Standards
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EPA-453/D-95-005a
Volatile Organic Compound Emissions
from Automobile Refinishing —
Background Information for Proposed
Standards
Emissions Standards Division
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Air and Radiation
Office of Air Quality Planning and Standards
Research Triangle Park, North Carolina 27711
August 1995
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TABLE OF CONTENTS
Page
1.0 INTRODUCTION • • - . 1'1
1.1 References • • 1~3
2.0 INDUSTRY DESCRIPTION 2-1
2.1 Industry Overview 2-1
2.1.1 Coating Manufacturers . 2-1
2.1.2 Coating Distributors ........ 2-2
2.1.3 Body Shops 2-3
2.2 Coating Types and Preparation 2-4
. 2.2.1 Lacquer Coatings 2-5
2.2.2 Enamel Coatings 2-5
2.2.3 Urethane Coatings 2-5
2.2.4 Waterborne Coatings 2-6
2.2.5 Additives and Specialty Coatings 2-6
2.2.6 Coating Preparation 2-6
2.2.7 Coating Systems 2-7
2.3 Process Steps and Materials 2-7
2.3.1 Surface Preparation 2-7
2.3.2 Primer Application 2-8
2.3.3 Primer Surfacer Application . . . 2-9
2.3.4 Primer Sealer Application .... 2-9
2.3.5 Topcoat Application 2-9
2.4 Preparation Stations 2-11
2.5 Spray Booths 2-11
2.6 Spray Equipment • • 2-15
2.6.1 Conventional Air Spray Guns ... 2-16
2.6.2 High-Volume, Low-Pressure
Spray Guns ........... 2-16
2.6.3 Low-Volume, Low-Pressure
Spray Guns . 2-18
2.6.4 Electrostatic Spray Guns .... 2-18
2.7 Equipment Cleaning 2-19
2.8 References 2-24
3.0 EMISSION CONTROL TECHNIQUES 3-1
3.1 Introduction 3-1
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TABLE OF CONTENTS (continued)
Page
3.2 Emission Reductions from
Coating Applications 3-2
3.3 Existing State Regulations 3-6
3.3.1 New Jersey 3-6
3.3.2 New York City . ; 3-6
3.3.3 Texas 3-6
3.5.4 California .. . , 3-6
3.4 References 3-9
4.0 BASELINE EMISSIONS AND EMISSION REDUCTIONS . . 4-1
4.1 • Coating Application 4-1
4.1.1 Baseline Volatile Organic
Compound Emissions
from Coating Applications . . . . 4-1
4.1.2 Reduction of Volatile Organic
Compound Emissions ,
from Coating Applications .... 4-5
4.2 References 4-6
5.0 COST IMPACTS 5-1
5.1 Costs to Coating Manufacturers 5-1
5.1.1 Process Modifications 5-1
5.1.2 Training Costs 5-2
5.1.3 Annual Costs to
Coating;Manufacturers 5-2
5.2 Costs to Distributors 5-2
5.3 Costs to Body Shops 5-2
5.3.1 Training Costs 5-2
5.3.2 Infrared Heating System Costs . . 5-4
5.3.3 Potential Productivity Losses . . 5-4
5.3.4 Annual Costs to Shops 5-6
5.4 Cost Effectiveness 5-6
5.5 References 5-7
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LIST OF FIGURES
Page
Figure 2-1. Typical infrared heating unit 2-12
Figure 2-2. Spray booth make-up and exhaust air
orientation 2-13
Figure 2-3. Conventional spray equipment 2-17
Figure 2-4. Typical enclosed gun cleaner 2-20
Figure 2-5. Typical open gun cleaner . 2-22
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LIST OF TABLES
Page
TABLE 3-1. COATING CONTROL OPTIONS 3-3
TABLE 3-2. EXISTING REGULATIONS 3-7
TABLE 4-1. 1995 BASELINE VOLATILE ORGANIC COMPOUND
EMISSIONS AND EMISSION REDUCTIONS (Mg/yr) 4-2
TABLE 4-2. 1995 COATING SOLIDS USE . . 4-3
TABLE 5-1. ANNUAL COSTS OF CONTROL TECHNIQUES (103 $) 5-3
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1.0 INTRODUCTION
National air quality monitoring data from 1989 through
1991 indicate that there are approximately 170 geographic
areas that failed to attain the National Ambient Air Quality
Standards (NAAQS) for ozone, with approximately 19 percent
being classified as being serious or severe, and 22 percent
being classified as being moderate or sub-marginal.1 Ozone is
a photochemical oxidant that is formed in the atmosphere
through a series of chemical reactions between precursor
emissions of volatile organic compounds (VOC's) and oxides of
nitrogen (NOX) in the presence of sunlight.
Although most large, stationary sources of VOC emissions
are covered by existing regulations, an examination of
emissions data completed in 1989 by the Congressional Office
of Technology Assessment (OTA) indicates that individual
small, dispersed sources of VOC's (area sources) contribute
significantly to the continuing ozone nonattainment problem.
According to the OTA report, "Catching Our Breath -- Next
Steps for Reducing Urban Ozone," one area source of VOC
emissions is the use of a wide range of consumer and
commercial products.2 This list of products includes
automobile refinish coatings.
Almost all automobile refinish coatings contain VOC's.
The volume used and VOC content are the primary factors that
affect the total amount of VOC's emitted by this product
category. The VOC emitted from automobile refinish coatings
includes VOC that are part of a coating's original
formulation, and VOC that are added during thinning or
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reducing, and VOC's released as reaction byproducts while the
coating dries and hardens. The total amount of VOC's emitted
from automobile refinish coatings was estimated to be about
88,500 megagrams per year.
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1.1 REFERENCES
1. Designation of Areas for Air Quality Planning Purposes,
40 CFR Part 81.
2. U. S. Congress, Office of Technology Assessment.
Catching Our Breath: Next Steps for Reducing Urban
Ozone. U. S. Government Printing Office. Washington,
B.C. Publication No. OTA-0-412. July 1989. p. 16.
1-3
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2.0 INDUSTRY DESCRIPTION
This chapter.describes the automobile refinish industry.
Section 2.1 provides an industry overview. Section 2.2
discusses the types of coatings used in refinishing. Section
2.3 describes the process steps and materials involved in
refinishing. Preparation stations are discussed in Section
2.4, spray booths in Section 2.5, spray equipment in
Section 2.6, and equipment cleaning in Section 2.7.
2.1 INDUSTRY OVERVIEW
As used in this document, "automobile" refers to passenger
cars, vans, motorcycles, trucks, and all other mobile
equipment that is capable of being driven or drawn upon a
highway, such as farm machinery and construction equipment.
"Refinishing" refers to any coating applications (to the
interior or exterior bodies of automobiles) that occur
subsequent to those at original equipment manufacturer (OEM)
assembly plants, and includes dock repair of imported
automobiles and dealer repair of transit damage before the
sale of an automobile.
The automobile refinish industry consists of manufacturers
that produce refinish coatings, distributors or "jobbers" that
distribute coatings and other equipment, and body shops that
repair and refinish automobiles.
2.1.1 COATING MANUFACTURERS
In 1989, sales of automobile refinish coatings in the
United States totalled slightly over $1 billion.1 Five
companies accounted for 95 percent of these sales: E.I.
du Pont de Nemours & Company, Inc., PPG Industries, The
Sherwin-Williams Company, BASF Chemicals, and Akzo Coatings.2
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Approximately one dozen smaller manufacturers supply the
remaining 5 percent.3 In the last few years, however, :several
other large foreign manufacturers have begun to enter the U.S.
market, namely, ICI Autocolor, Spies Hecker, and Herberts
Standox.
The five major manufacturers also produce components such
as catalysts, solvents ("thinners" or "reducers"), and
additives for use with their coatings. Approximately two dozen
other U.S. manufacturers produce lower-cost coating components
that are marketed for use with the coatings produced by the
major manufacturers.4 However, the major manufacturers report
that these lower-cost components may reduce the overall
quality of their 'coatings and, consequently, will not honor
their warranties if such components are added to their
products.5
2.1.2 COATING DISTRIBUTORS
Distributors of refinish coatings also sell mixing
components and other products used for refinishing, such as
mixing stations, infrared heating lamps, sandpaper, and
masking tape. Some distributors also sell equipment and
products necessary to perform body repairs. Distributors
provide body shops with valuable product support services such
as training in new products and equipment, mixing of topcoat
colors, troubleshooting advice, and general product
information.
Although at least one coating manufacturer, The
Sherwin-Williams Company, operates retail stores that
distribute only Sherwin-Williams products,6 the large majority
of the approximately 5,000 distributorships in the United
States are not owned or operated by coating manufacturers.
Another 10,000 body part distributors also sell refinish
products.7 Both types of distributorships are known as paint,
body supply, and equipment (PBE) specialists, and are commonly
referred to as "jobbers" or "refinish jobbers."
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2.1.3 BODY SHOPS
There are approximately 50,000 body shops of various sizes
and technology levels in the U.S.,8,9,10 including small-size
shops, medium-size shops, shops at new car dealerships, and
large "production" shops. The work performed by most small -
and medium-size body shops, which comprise most of the
industry, is somewhat confined to repairing and refinishing
small portions of an automobile (e.g., a panel, or a "spot" on
a panel). About 90 percent of refinish work performed is spot
repair.11,12 sixty percent of new-car dealerships
(approximately 13,500 facilities nationwide) reportedly
operate body shops.13 New-car dealers refinish not only new
cars damaged in shipment, but also cars that are brought in by
customers for repair. Other types of shops specialize in
repainting entire automobiles and are often referred to as
"production" shops.
Although body shops in some areas of the United States
must obtain permits or licenses to operate, painters are
rarely required to be licensed.14'15 Painter training is
often provided by coating manufacturers and distributors and
by trade organizations, but no formal apprenticeship programs
have been instituted by the industry.
In contrast, the refinish industry in several European
countries is reportedly structured differently. For instance,
in Germany, the refinish industry comprises large,
sophisticated shops.16 In Holland, painters are required to
be trained, pass a test, and obtain a license.17 In several
European countries, painters usually participate in
apprenticeship programs. These apprenticeships are not
usually mandatory, but are part of the European culture."
The refinish industry in the United States is a dynamic
industry that has changed dramatically in the past decade.19
The industry is shifting away from a large number of small
facilities toward fewer, larger shops, primarily because of
worker health and safety issues and hazardous waste management
concerns.20 It is estimated that there were approximately
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125,000 shops in operation in 1976, but by 1993 the number
decreased to approximately 50,000.21
2.2 COATING TYPES AND PREPARATION
The main categories of coatings are primers and topcoats.
The primer category consists of pretreatment wash primers,
primers, primer surfacers, and primer sealers. Topcoats are
applied over the primer coats and provide the final color to
the refinished area.
Primers and topcoats can be classified as lacquer, enamel,
or urethane coatings. These coatings differ in their
chemistry, durability, and VOC content. Lacquer coatings cure
by solvent evaporation only. Enamel and urethane coatings
cure by solvent evaporation and chemical cross-linking
reactions.22
Lacquers and some types of enamel coatings consist mainly
of pigment, resin, and solvent (thinner or reducer). The
resin and pigment are collectively referred to as coating
"solids" or "nonvolatiles" because they remain on the
substrate to form the dry film. Solvents suspend the solids
in solution and reduce the viscosity so that the coating flows
into a uniform film on the substrate. The solvents evaporate,
and only trace quantities remain in the film on the substrate.
In addition to the coating components discussed above,
urethanes and some enamel coatings use catalysts (or
hardeners) to initiate the chemical cross-linking.
Urethane coatings typically have a much higher volume
percent solids than lacquers and a slightly higher percentage
than enamels. This is an important feature because, as
mentioned above, the coating solids are the permanent part of
the paint that remain on the surface as a film. The greater
the solids content of a coating, the less coating required to
obtain the desired film thickness.
The coatings applied by body shops differ from those
applied by OEM's. OEM facilities use coatings that require
temperatures up to 400 °F (204 °C) to cure the paint. This is
possible because no temperature-sensitive materials have yet
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been installed in the automobile. Body shops, on the other
hand, must use coatings that cure at low temperatures (less
than 150 °F [66 °C]) to avoid damaging the automobile's
upholstery, glass, wiring, or plastic components.
2.2.1 Lacquer Coatings
Lacquers were one of the first types of coatings used on
automobiles. Lacquers dry faster than most enamels or
urethanes and, when dry, can be buffed to remove surface
imperfections. These characteristics are attractive to body
shops that do not have spray booths because the rapid drying
helps minimize the opportunity for dirt to be trapped in the
wet coating. One disadvantage of lacquers is that time and
labor must be expended in buffing (compounding) lacquer
finishes to achieve full luster.23 Another disadvantage is
that lacquer finishes are not as durable as enamel and
urethane finishes.
2.2.2 Enamel Coatings
Enamel coatings, either alkyd or acrylic, have long been
used in the automobile refinish industry. Alkyd enamel is a
chemical combination of an alcohol, an acid, and an oil.
Developed in 1929, alkyd enamels are less expensive than
acrylic enamels but not as durable. Some acrylic enamels
require hardeners to promote curing. Both types of enamels
have a natural high gloss and do not require compounding to
remove surface imperfections. Some enamel coatings can be
polished, if necessary, to remove trapped dirt or dust.
2.2.3 Urethane Coatings
Urethane coatings are typically formed by a reaction
between a hydroxyl-containing material and a polyisocyanate
hardener. Their use is growing because of their superior
gloss retention and durability. They are frequently used by
the more technically sophisticated body shops for complete
refinish jobs, such as refinishing of fleet vehicles.24
Urethane coatings dry more slowly than lacquers and
enamels, and spray booths may be necessary to reduce drying
time and provide a clean, dust-free curing environment. The
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possible presence of trace amounts of residual isocyanates
requires painters to use an air-supplied respirator to reduce
worker exposure. Isocyanate-free hardeners are available for
use in some coating systems.25
2.2.4 Waterborne Coatings
A waterborae coating contains more than 5 weight-percent
water in its volatile fraction.26*27 Like enamel and urethane
coatings, waterborne coatings dry relatively slowly. The use
of a spray booth may be necessary to prevent contamination,
and infrared heating equipment may be necessary to facilitate
drying.
2.2.5 Additives and Specialty Coatings
Some additives and specialty coatings are necessary for
unusual performance requirements, and are used in relatively
small amounts to impart or improve desirable properties.
Problems such as "fish eye" defects (a surface imperfection
that can occur when the old finish contains silicone) can be
prevented by the use of additives. Additives and specialty
coatings include adhesion promoters, uniform finish blenders,
elastomeric materials for flexible plastic parts, gloss
flatteners, and anti-glare/safety coatings.
2.2.6 Coating Preparation
Most coatings are mixed with additional solvents (and
sometimes catalysts) prior to application to ensure proper
drying time, adhesion, appearance, and color-match. Topcoats
in particular must be mixed exactly according to the
manufacturer's instructions because even a slight deviation
may result in unacceptable finish quality.
Many shops order topcoats to match the automobile being
refinished from local automotive paint distributors. Others
mix their own colors using mixing stations. .A mixing station
typically consists of a microfiche viewer or a computer that
contains the coating manufacturer's mixing instructions, a
digital scale, and a mixing machine. Shops that use mixing
stations typically stock only a few primary colors, from which
almost any OEM color can be produced.28 According to an
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industry survey, about one-half of all shops own mixing
machines.29 Almost all lajfge volume or sophisticated shops
own mixing stations, but few small shops (those employing only
one or two painters) own them.30
Shops that mix their own coatings strive to mix as little
as possible to complete a job, but always with a slight excess
to ensure that enough is available to complete the job. By
minimizing the excess, the shop minimizes the cost of
materials and the amount and cost of hazardous coating waste
disposal.
2.2.7 Coating Systems
All of the major coating manufacturers market specific
brands of primer and topcoat products as "systems." All of
the coatings within a particular manufacturer's coating system
are compatible and, according to the manufacturers, should be
used exactly according to instructions and never interchanged
with coatings from other systems.31 Problems with adhesion,
durability, and recoatability are reportedly common if coating
systems are not maintained.32
2.3 PROCESS STEPS AND MATERIALS
The procedures for refinishing automobiles vary from shop
to shop; however, some basic steps are followed, whether the
job is to repair a spot, panel, or entire automobile.
Generally, the surface is thoroughly cleaned to ensure proper
adhesion of the coating, the metal surface is primed, a
topcoat is applied, and the spray equipment is cleaned.
The following subsections describe the surface preparation
and coating application processes. The spray equipment
cleaning process is discussed in Section 2.6.
2.3.1 Surface Preparation
The first step in the refinish process is preparing the
surface. The surface is normally washed with detergent and
water and allowed to dry. It is then cleaned with either
solvent or a solvent-based surface preparation product
(solvent wipe) to ensure removal of all remaining wax, grease,
and other contaminants.
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Surface preparation products generally contain solvents
(toluene, xylene, and petroleum distillates) and
surfactants.33 These products are wiped off after they have
effectively dissolved the wax and grease from the surface.
This step is important to avoid contamination and ensure
proper adhesion of the coatings, and is necessary even if the
existing paint does not have to be removed or if the parts to
be coated are new. Some shops use waterborne, low-VOC surface
preparation products instead of solventborne products.
If an existing primer/topcoat is in good condition (no
chips or cracks), the new paint can be applied directly on top
of it by merely "scuff-sanding" (or roughening) the surface to
promote adhesion.' If the existing finish has imperfections or
the part has been damaged in an accident, the old finish
should be completely removed down to bare metal.
Removal of old paint is by one of three methods: (1) by
sanding (best for small areas), (2) with paint removers (which
typically contain solvents such as methylene chloride,
methanol, and ammonia, and are most efficient for large areas
and complete panels), or (3) by sand blasting (best for
complete automobiles or extremely large areas). 34»35 The
paint removal step is followed by a final solvent wipe.
2.3.2 Primer Application
Before any coatings are applied to bare metal, the surface
should be treated with a metal conditioner to etch the surface
and prevent flash rusting, which can occur from bare metal
exposure to the atmosphere. Metal conditioning can be
achieved using a hand-applied acidic conditioner, or by the
application of a pretreatment wash ("self-etching") primer,
that both etches and primes the surface. Pretreatment wash
primers contain at least 0.5 percent acid by weight, and can
be applied prior to the application of solventborne or
waterborne coatings. If a pretreatment wash primer is not
used, the conditioned surface should be primed to provide
corrosion resistance and promote adhesion.36
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The term "precoat" has been used in several State
automobile refinish rules to describe a bare metal coating
category. A precoat is described as a coating that is applied
to bare metal prior to the application of waterborne coatings.
When pretreatment wash primers cannot be used (i.e., when they
are incompatible with the substrate or other coatings),
primers or primer sealers can be used to prepare the surface
for subsequent waterborne coatings; therefore, a separate
11 precoat" category is not necessary.
2.3,3 Primer Surfacer Application
If imperfections remain in the surface after primer
application, a primer surfacer is applied. Primer surfacers
build film thickness in order to create a smooth surface after
sanding, and provide adhesion and corrosion resistance.
2.3.4 Primer Sealer Application
If there are no surface imperfections, some shops apply
only a primer sealer to provide more corrosion resistance,
promote adhesion of subsequent coatings, and enhance the
uniform appearance of the topcoat. Primer sealers prevent
dulling of the topcoat caused by the penetration of topcoat
solvents into the primer and primer surfacer coats.
2.3.5 Topcoat Application
The topcoat system, applied after the surface is prepared
and free of defects, provides the final color and appearance.
Topcoats may be single-stage, two-stage, or three-stage
coating systems. Each stage of a two- or three-stage system
directly impacts the durability of the topcoat system, and the
ability to successfully match the old paint color.
Two-stage basecoat/clearcoat systems may have either a
solid color or a metallic basecoat, covered by a transparent
clearcoat for protection and gloss. The basecoat is
approximately one-third and the clearcoat two-thirds of the
total coating used.37'38'39 Two-stage systems are popular
because of their deep, rich finish, which reportedly cannot be
duplicated by a single-stage coating.
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Metallic finishes contain small metal flakes, typically
aluminum, which are suspended in a mixture of binders,
solvent, and pigment. Light reflects off these metal flakes
to produce the metallic effect. Color-matching these coatings
is difficult and depends on the alignment of the metallic
particles, which is influenced by the evaporation rate of the
solvent. OEM's use metallic coatings on at least 50 percent
of all new automobiles.40
Three-stage systems consist of a basecoat, midcoat, and
clearcoat. The basecoat and midcoat account for about
one-half of the coating volume and the clearcoat for
one-half.41'42 Three-stage refinish systems are often used to
match three-stage OEM finishes.43
Three-stage iridescent finishes are similar to metallic
finishes; they contain flakes of mica in the midcoat that
reflect light to produce an iridescent, or "pearl", effect.
As OEM topcoats have become more complex, the precise
matching of original colors by painters has become more
difficult. Annual changes in OEM color selections add a
dimension of difficulty to achieving color-match. An
automobile manufacturer typically will introduce over 10 new
colors in a single year.44 New car colors are developed by
coating manufacturers, who preview them with automobile
manufacturing stylists. The automobile manufacturer then
determines from market research which colors to use.
Once a new color has been selected, the coating
manufacturers develop coatings that achieve the desired
appearance and performance specifications. Trial application
by the automobile manufacturer may then take a number Of
months before the coating is approved for line application.
The typical automobile painter, however, lacks this period
of "trial application" and is expected to meet color
specifications and customer satisfaction for every job,
regardless of previous experience with a particular color.
Although refinish coating formulations are developed for each
OEM color, there is often variability in the shade color,
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which requires the painter to make adjustments to the formula.
Because of the difficulty of matching certain colors, the
painter must sometimes refinish more of the automobile rather
than just the damaged portion. This, of course, increases
coating usage.
2.4 PREPARATION STATIONS
Preparation of the surface for repainting and application
of the primer usually are done in open areas of body shops;
however, in some shops these steps are performed in
preparation, or "prep", stations. Prep stations typically are
ventilated and equipped with plastic curtains to control dust
and coating overspray. Many shops are equipped with portable
infrared heating units to facilitate drying of primers during
cool and/or humid shop conditions. Figure 2-1 presents a
diagram of a typical heating unit.
2.5 SPRAY BOOTHS
Spray booths are clean, well-lit, and well-ventilated
enclosures for coating operations. Because of their longer
drying times, enamel, water-based, and urethane coatings are
best applied in a spray booth to minimize the possibility of
dirt adhering to the wet coating. Air is drawn into a spray
booth through filters to assure a flow of clean air past the
automobile being painted. This air hastens drying and
provides a safer work environment for the painter by removing
solvent vapors from the booth. Filters in the discharge from
the booth remove coating overspray (the portion of the coating
solids that does not adhere to the surface being sprayed) from
the exhaust air.
There are three types of spray booths used in the refinish
industry: crossdraft, downdraft, and semi-downdraft (Figure
2-2). Traditionally, the air flow in refinish spray booths
has been from one side of the booth to the other, or
11 crossdraft." In the crossdraft design, incoming air is
pulled into the booth through filters located in the entrance
door. The air travels along the length of the car and then
passes through coating arrester.filters at the opposite end,
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Figure 2-1. Typical Infrared Heating Unit
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M«k»-upAir
i i i r i i r i
?... t ? ? t f t t ? ?
Exhcutt Trench
Downdraft
Semi-downdraft
Crossdraft
Figure 2-2. Spray booth make-up and exhaust air orientation
!
a
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where coating overspray is removed. The air then exits
through an exhaust stack, carrying with it any solvent vapors
or other VOC's.
Downdraft booths have a vertical air flow (top to bottom)
and are considered state-of-the-art because they provide the
cleanest drying/curing environment. In a downdraft booth, the
air is pulled in through filters in the roof, travels down
over the top of the automobile, picks up coating solvent and
overspray, and passes into a grate-covered pit in the floor of
the.booth.
The downdraft booth is a better design than the crossdraft
booth because the air is less turbulent, which helps minimize
the mixing of overspray with air in the rest of the booth. In
addition, air circulation is more uniformly concentrated
around the automobile and solvent vapor is drawn down and away
from the painter's breathing zone.
Downdraft booths can utilize dry-filtration or
wet-filtration (waterwash) systems to capture coating
overspray. In wet-filtration booths, water is used to capture
overspray. Both types of filters only remove coating solids;
they do not reduce VOC emissions to the atmosphere.
The semi-downdraft spray booth is a combination of
crossdraft and downdraft booth designs. Air enters the booth
through the ceiling and is discharged at the back of the
booth. Air in a semi-downdraft spray booth is more turbulent
than in a downdraft booth but less turbulent than in a
crossdraft booth.
In order to decrease the drying time after coating
application, most shops with spray booths use heated air
drying systems. Smaller shops may use traveling ovens that
can be rolled out for use inside the booth after the
automobile has been sprayed. Small, portable, infrared
heating units are also available either to warm metal surfaces
prior to coating application or to speed the drying time of
the repair.
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Approximately 40 percent of all body shops own crossdraft
booths and 30 percent own downdraft or semi-downdraft
booths.45 The portion that can heat the booth air is not
known. As the refinish industry continues to move away from
lacquer coatings and toward slower drying higher-solids and
waterborne coatings, shops that do not already have spray
booths are expected to purchase them.
2.6 SPRAY EQUIPMENT
Current practice in the refinish industry is to apply
coatings with hand-held spray guns that use air pressure to
atomize the coating. There are two basic types of spray gun
systems: pressure-feed and suction-feed. In a pressure-feed
system, the coating is contained in a "pot" that is connected
by hose lines to the spray gun. Compressed air introduced to
the pot pushes the liquid through the hose and out of the
spray gun nozzle. Pressure-feed systems generally require
significantly more coating than suction-feed because of the
amount of residual coating in the pressure pot and hose lines.
In a suction-feed system, coating is contained in a "cup"
mounted on the spray gun. The rapid flow of air through the
air line and spray gun creates a vacuum which draws the
coating from the cup and forces it through the gun nozzle.
Based on available data, it is clear that some spray
equipment is likely to give better transfer efficiency than
others. Simply defined, transfer efficiency is the ratio of
the amount of coating solids deposited onto the surface of the
coated part to the total amount of coating solids that exit
the gun nozzle. Paint that is sprayed but not deposited onto
the surface is referred to as "overspray." Increased transfer
efficiency, or reduction of coating overspray, has a number of
benefits. Because coating overspray releases the same amount
of solvent as the coating that adheres to the substrate,
reducing overspray reduces VOC emissions.
Less overspray also benefits the refinisher. Solvent
concentration in the booth is reduced, less time is spent
applying coatings (because more reaches the substrate), and
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solvent use for cleanup of overspray is reduced.
Additionally, a shop that uses high-transfer efficiency spray
equipment uses less coating, and therefore may also realize a
savings in coating costs. The transfer efficiency of spray
guns vary dramatically depending on a number of factors, such
as the shape of the surface being coated, type of gun,
velocity of the aerosol, skill and diligence of the operator,
and extraneous air movement within the spray booth.
2.6.1 Conventional Air Spray Guns
Conventional air spray guns are suction-feed and are the
standard method of applying coatings. Figure 2-3 shows the
two basic types of conventional spray guns: syphon-feed and
gravity-feed. In syphon-feed guns the paint cup is attached
below the spray gun, and the rapid flow of air through the gun
creates a vacuum that siphons the coating out of the cup.
Gravity-feed guns, which have the paint cup attached above the
gun, require less air pressure to move the coating through the
gun and provide substantially better transfer efficiency than
syphon-feed guns.46
The air pressure at which conventional spray guns operate
is usually 30 to 90 pounds per square inch (psi). One of the
major problems with these guns is that the high velocity of
the aerosol causes the coating particles to "bounce", which
increases overspray. The transfer efficiency of conventional
spray guns is substantially lower than that of "high-volume,
low pressure" (HVLP) spray guns.
2.6.2 High-Volume. Low-Pressure Spray Guns
High-volume, low-pressure spray guns use large volumes of
air at low pressure (10 psi or less) to atomize coatings.
Because the atomized spray leaves the gun at a lower velocity
than in conventional air spraying, there is less particle
"bounce." As a result, higher transfer efficiency can be
achieved, with overspray reportedly being reduced by 25 to 50
percent.47
The air source in an HVLP spray system can be a turbine or
conventional compressed air. Both systems can be purchased to
2-16
-------
Syphon-Feed
Gravity-Feed
Figure 2-3. Conventional spray equipment
2-17
-------
handle multiple spray guns. The materials of construction of
most HVLP systems are designed to be compatible with a full
range of coatings. Many HVLP spray systems are .designed to
atomize high-, medium-, and low-solids coatings.
When first using HVLP spray equipment, the painter must
adjust to the different characteristics of the spray pattern.
Initially, HVLP spray guns are more difficult to use,
especially for color-matching, because the greater transfer
efficiency requires that the painter move the gun more quickly
in order to avoid applying an excessively thick coat. Thick
films can cause splotching, which occurs when solvent
initially trapped in the thicker coating escapes to the
surface and causes a blemish. Also, thicker films retard the
evaporation rate of the solvent, which can influence the
positioning of metallic flakes. In addition, the HVLP spray
requires more skill to blend.48 Once a painter becomes
experienced with HVLP guns, however, these problems are
overcome, with a significant cost savings because the amount
of waste coatings can be reduced with no sacrifice in the
quality of the refinished surface.
2.6.3 Low-Volume. Low-Pressure Spray Guns
Low-volume, low-pressure (LVLP) spray guns are quite
similar to HVLP spray guns in that atomized coatings are
released at lower pressure (9.5 to 10 psi) and lower velocity
than conventional air spray guns. The transfer efficiency of
LVLP spray guns is reportedly about the same as for HVLP spray
guns. The primary difference is that LVLP guns use a
substantially smaller volume of air for paint atomization (45
to 60 percent less). Consequently, energy costs for air
compression are less than with HVLP guns.4^
2.6.4 Electrostatic Spray Guns
Electrostatic spray systems create an electrical potential
between the coating particles and the substrate. The charged
coating particles are attracted to the substrate, thus
reducing overspray and increasing transfer efficiency.
2-18
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Typical electrostatic spray systems are pressure-feed.
A large amount of coating is contained in the hose that
connects the spray gun to the paint pot. It must be removed
before the next coating can be applied with the gun. These
designs appear impractical for the refinish industry,
primarily because refinish facilities change coatings so
often.50 In addition, the cost of electrostatic spray systems
may be prohibitive for most body shops.51
It has been reported that there are explosion and
electrocution risks associated with use of electrostatic spray
guns unless very strict operating procedures are observed.52
Foremost, it is necessary to establish and maintain proper
electrical grounding of all metallic objects in electrostatic
spray areas, especially solvent and paint containers. If
improperly grounded, these objects can develop high-voltage
charges as they come in contact with the electrified air
molecules and paint molecules. A spark near these objects may
easily ignite any surrounding solvent vapors.53 Users of
electrostatic spray equipment should carefully observe all
manufacturers' operating procedures.
2.7 EQUIPMENT CLEANING
Spray equipment can be cleaned manually or with any of
several types of gun cleaning systems specifically designed
for this purpose. About 60 percent of all body shops
reportedly use some type of gun cleaning system.54'55 Shops
that do not have spray gun cleaning systems usually rinse the
outside of the gun and cup, add solvent to the cup, and then
spray the solvent into the air or into a drum set aside for
spent solvent.56
An enclosed gun cleaner or washer (Figure 2-4) consists of
a closed container (much like an automatic dishwasher with a
door or top that can be opened and closed) fitted with
cleaning connections. The spray gun is attached to a
connection, and solvent is pumped through the gun and onto the
exterior of the gun. The paint cup is also placed in the
cleaner, where the interior and exterior are sprayed with
2-19
-------
Spray Nozzto
Gun Support
Pump Tubing
(nMRttw
and Tubing
Solvent Basin
Pump
Figure 2-4. Typical enclosed gun cleaner
2-20
-------
solvent. Many gun cleaners are capable of cleaning two guns
and cups per cleaning and are typically designed to clean
other equipment such as paint stirrers and strainers.
Cleaning solvent falls back into the cleaner's solvent
reservoir for recirculation. Solvent is recirculated until it
is too contaminated for further use. Some enclosed gun
cleaners are equipped with a second solvent reservoir that
contains virgin solvent that is used as a final rinse.
A typical open gun cleaner, shown in Figure 2-5, consists
of a basin similar to a sink in which the operator washes the
outside of the gun under a solvent stream. The gun cup is
filled with recirculated solvent, the gun tip is placed into a
canister attached to the basin, and suction draws the solvent
from the cup through the gun. The operator then removes the
cup, places the gun's suction stem under the clean solvent
spigot, pulls the trigger, and pumps solvent through the gun.
The solvent gravitates to the bottom of the basin and drains
through a small hole to a reservoir that supplies solvent to
the recirculation pump. The recirculating solvent is changed
when it no longer cleans satisfactorily.
Waste solvents generated by spray equipment cleaning are
often disposed of by evaporation (via spraying into the air,
or by placing in open drums) or incineration, or are reclaimed
via distillation. Solvent can be reclaimed either at the shop
or off-site. Off-site solvent reclaimers collect spent
solvent from body shops, distill it, and return clean solvent
to the shops. Some companies provide this service only for
those shops that rent their gun cleaning systems.
In-house recycling can be as simple as letting spent
solvents settle and decanting the "clean" layer for reuse.
This method, gravity separation, is used where the purity of
the solvent is not critical. Some on-site distillation units
produce a more refined solvent, which reduces the amount of
new solvent that must be purchased and eliminates disposal
fees for the reclaimed solvent.
2-21
-------
Figure 2-5,
Typical open gun cleaner
2-22
X
I
3
-------
Care must be taken when a solvent reclaim unit is to be
placed in use. Solvents are combustible and can also be an
explosion hazard.57 Explosion hazards are possible from the
distillation residues that contain nitrocellulose.
Nitrocellulose is found in lacquer paint but would not be
expected in enamels and urethanes.58 In addition, some
on-site reclaimers are not explosion-proof and may pose a
hazard when operated near other non-explosion-proof electrical
equipment. It is recommended that reclaim equipment be
operated outdoors and away from spark-producing equipment, and
that the power is turned off when the machine is being
emptied.59
The use of solvent for gun cleaning can reportedly be
reduced by using teflon-lined paint cups, which makes paint
removal easier. Some facilities use a small plastic liner
inside the paint cup to make cleanup easier and reduce solvent
use. The paint-covered plastic liner is discarded after each
use and the paint cup remains essentially free of paint.
2-23
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-------
2.8 REFERENCES
l. Rauch Associates, Inc. The Rauch Guide to the U. S. Paint
Industry. ISBN 0-932157-00-09. 1990. p. 85.
2. National Paint and Coatings Association/ NPCA Automotive
Refinish Coalition's Estimates of 1990 National Baseline
VOC Emissions from the Automotive Refinish Industry.
Washington, DC. March 1992.
3. Telecon. Sullivan, J., Radian Corporation, with
Schultz, K. R., E. I. du Pont de Nemours & Company, Inc.
April 9, 1993. Estimate of the number of refinishing
coating manufacturers in the United States.
4. Ref. 3
5. Letter from Sell, J., Automotive Refinish Coalition to
Jordan, B., EPA/CPB. December 2, 1991. Automotive
Refinish Coalition's additional comments concerning
technical and factual issues raised by the study, p. 2. .
6. Ref. 1
7. Letter from Roland, D., Automotive Service Industry
Association, to Ducey, E., EPA/CPB. January 22, 1993.
Distributors of automotive refinishing coatings.
8. Collision Repair Industry. Repair in the 90's. Insight
1:5. February, 1991.
9. Letter from Graves, T. J., Esq., National Paints and
Coatings Association, to South Coast Air Quality
Management District. July 8, 1988. Automobile
refinishing industry characterization and regulation.
10. Meeting Summary from Sullivan, J. W., Radian Corporation,
to Schultz, K. R., E. I. Du Pont de Nemours & Company,
Inc., July 29, 1992. Baseline emission estimates for the
automobile refinishing industry.
11. Sell, J. Position Paper of the NPCA Automotive Refinish
Coalition Concerning Draft Automobile Refinishing Control
Techniques Guidelines. In: National Air Pollution
Control Techniques Advisory Committee. Research Triangle
Park, N.C. Office of Air Quality Planning and Standards.
November 21, 1991. p. 1081.
12. Schultz, K. R., E. I. Du Pont de Nemours & Company, Inc.
Comments on the Automobile Control Techniques Guideline
Draft for NAPCTAC Review on 11/21/91. In: National Air
Pollution Control Techniques Advisory Committee. Research
2-24
-------
Triangle Park, NC. Office of Air Quality Planning and
. Standards. November 21, 1991. p.1070.
13. Letter from Randall, D. A., Automotive Service
Association, to Ducey, E., EPA/CPB. June 27, 1991.
Summary of Automotive Refinishing Model Shop Emission
Reduction Costs.
14. Ref 13.
15. Letter from French, R., Collision Industry Conference, to
Ellen, D., EPA/CPB. October 11, 1992. Body shop
licensing.
16. Telecon. Shaw, I., Radian Corporation, with Sieradski,
R., Akzo Coatings, Inc. October 12, 1992. European
automobile refinishing industry.
17. Ref. 16°.
18. Ref. 16.
19. Ref. 9.
20. Ref. 11.
21. Memorandum from Campbell, D. L., Radian Corporation, to
Ducey, E., EPA/CPB. June 19, 1990. Trip report of site
visits with Sherwin-Williams Sales Manager, Doug Smith.
22. PPG Refinish Manual. PPG Industries. 1989.
23. Ref. 22.
24. Memorandum from Ross A., EPA/ORD, to Ducey, E., EPA/CPB.
September 17, 1991. Urethane Dispersions in Automotive
Refinishing.
25. Letter from Sell, J., Automotive Refinish Coalition to
Jordan, B., EPA/CPB. December 2, 1991. Automotive
Refinish Coalition's Additional Comments Concerning
Technical and Factual Issues Raised by the Study, p. 2.
26. Athanson, W. J. World Automotive Chemical Coatings--
Solvents Glossary. D. Van Nostrand Co., New York, NY.
1989. p. 89.
27. U. S. Environmental Protection Agency, Office of Air
Quality Planning and Standards. Glossary for Air
Pollution Control of Industrial Coating Operations. Second
Edition. EPA-450/3-83-013R. Research Triangle Park, NC.
December 1983. p. 23.
2-25
-------
28. Telecon. Sullivan, J., Radian Corporation, with
Smith, D., Sherwin-Williams Company. January 10, 1992.
Paint mixing and recofdkeeping.
29. Babcox Publications. 1993 Annual Industry Profile. June
1993. p. 51.
30. Ref. 28.
31. Ref. 11. pp. 1076, 1081, and 1082.
32. Clark, M. Common Complaints, Specific Solutions. Body
Shop Business. June 1990. pp. 80-81.
33. Athey, C., C. Hester, M. McLaughlin, R.M. Neulicht, and
M.B. Turner. Reduction of Volatile Organic Compound
Emissions from Automobile Refinishing. U.S. Environmental
Protection Agency, Research Triangle Park, North Carolina.
EPA-450/3-88-009. 1988.
34. Ref. 22.
35. Telecon. Sullivan, J., Radian Corporation, with
Smith, D., Sherwin-Williams Company. April 23, 1992.
Coating preparation.
36. Bay Area Air Quality Management District. Staff Report on
Proposed Regulation 8, Rule 45 - Motor Vehicle and Mobile
Equipment Coating Operations. May 1, 1989.
37. Letter from Schultz, K., E.I. Du Pont de Nemours &
Company, Inc., to Brower, G.> New Jersey Department of
Environmental Protection. January 24, 1989. pp. 3,4.
New Jersey Refinish Rule Development Procedures.
38. Inglis, R. J. BASF Comments on Draft Automobile Control
Techniques Guideline. In: National Air Pollution Control
Techniques Advisory Committee. Research Triangle Park,
N.C. Office of Air Quality Planning and Standards.
November 21, 1991. Pp. 1012-1019.
39. Ocampo, G., Sherwin-Williams. Comments on Draft
Automobile Control Techniques Guideline. In: National
Air Pollution Control Techniques Advisory Committee.
Research Triangle Park, NC. Office of Air Quality
Planning and Standards. November 21, 1991. pp. 1045-
1048.
40. Ref. 32.
41. Ref. 38.
42. Ref. 39.
2-26
-------
43. Ref. 22.
44. Ref. 38.
45. Norton, J. 1992 Annual Industry Profile. Body Shop
Business. 11:56. June 1992.
46. Memorandum from Campbell, D. L., Radian Corporation, to
Ducey, E., EPA/CPB. June 20, 1990. Revised trip report--
CBWD's, Inc.
47. Graco, Incorporated. Product Information. High Output
HVLP Sprayers. 1990.
48. Ref. 33.
49. Telecon, Sullivan J., Radian Corporation, with Thomas, M.,
IWATA Paint Spray Equipment Manufacturing Company.
November 26, 1992. Low-volume low-pressure spray guns.
50. Ref. 13
51. Ref. 33
52. Adams, J. New Application Methods and Techniques. Binks
Manufacturing Company. Franklin Park, IL. In: SPCC '91
National Conference and Exhibition. Long Beach, CA.
November 13, 1991. p. 37-56.
53. Ref. 52.
54. Telecon. Soderberg, E., Radian Corporation with Kusz, J.,
Safety Kleen Corporation. January 8, 1991. Gun
cleaners.
55. Telecon. Campbell, D.L., Radian Corporation, with
Schultz, K., E.I. Du Pont de Nemours & Company, Inc.
December 12, 1990. Coating cost and industry
characterization.
56. Ref. 54.
57. Gwynn, Sandra. Are Recylers Safe? Hammer and Dolly.
June 1992. pp. 37 and 38.
58. Ref. 57.
59. Ref. 57.
2-27
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3.0 EMISSION CONTROL TECHNIQUES
3.1 INTRODUCTION
The steps involved in automobile refinishing include surface
preparation, coating application, and spray equipment
cleaning. Although each of these steps can be a source of VOC
emissions, regulated entities under the National Rule include
only coating manufacturers and importers; therefore, coating
application is the only source of emissions that can be
reduced by standards for such entities. Achieving reductions
from surface preparation and spray equipment cleaning would
require standards at the coating user level. This chapter
discusses the use of low-VOC coatings for reducing VOC
emissions from coating application.
Before discussing techniques to reduce the VOC emissions
from coating application, it is necessary to discuss the
methodology used to determine the VOC content of coatings. As
explained in Chapter 2, the solids portion of a coating
remains on the substrate to form the film; therefore, the VOC
content of a coating ideally would be related to its volume
solids. There is as yet, however, no generally accepted
method for the determination of the solids content of
coatings. This document continues the EPA's approach of
relating the mass of VOC in a coating to the combined volumes
of VOC and solids, expressed as: mass of VOC per unit volume
of coating, minus volume of water and any negligibly
photochemically reactive ("exempt") compounds. Unless
otherwise stated, the VOC contents discussed in this document
represent the amount of VOC in the coating as it is applied,
3-1
-------
that is, after it has been prepared for application according
to the manufacturer's mixing instructions.
3.2 EMISSION REDUCTIONS FROM COATING APPLICATIONS
Information on low-VOC coatings was gathered through a
survey of the major manufacturers of automobile refinish
coatings conducted by the EPA in March of 19901 and from
coating product literature. This information indicates that
all of the major manufacturers have developed coatings that ,
contain substantially less VOC than conventional coatings.
Some of these coatings have been developed to comply with
several State regulations that mandate their use.
Table 3-1 lists the various coatings used in automobile
refinishing-and the VOC contents of conventional coatings.
This table also presents VOC content limits for the various
coatings, which are organized into three options.
The limits of Option 1 were derived by evaluating the
technical feasibility, cost, and reported limitations of
coatings that are currently available. Coatings at the Option
1 limits would not require the purchase of any additional
equipment by body shops. Therefore, shops at all levels of
technical sophistication should be able to use these coatings
with no loss of productivity or quality.
The Option 2 limits were suggested by coating manufacturers
several years ago when they anticipated that such coatings
could be developed before they were required by a rule. The
Option 2 limit of 600 grams of VOC per liter (g VOC/O for 3-
stage topcoats is claimed by manufacturers to be "technology-
forcing" because there are no coatings currently available at
these limits. There are primer/primer surfacers available
that meet the Option 2 limit; however, equipment (such as
heating lamps) would likely have to be purchased by users to
speed the drying of these slower-drying coatings.
The VOC limits of Option 3 are identical to the limits
determined to be Best Available Retrofit Control Technology
(BARCT) by the California Air Resources Board (GARB)
(effective January l, 1992 through December 31, 1994), except
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for the precoat.2 These coatings are currently available;
however, their longer drying times would also require the
purchase of additional equipment by shops in geographical
areas with weather conditions less favorable than
California's.
The VOC contents of conventional pretreatment wash primers
range from 695 to 780 g VOC/£; the average is approximately
755 g VOC/£.3 A limit of 780 g VOC/£ is included in all
options to ensure that this bare metal coating can be applied
in.a thin film and that it will be compatible with subsequent
coatings. No emission reductions are anticipated from
pretreatment wash primers, but significant reductions could
not be expected since only about two percent of total
automobile refinish emissions result from their application.
Precoats contain between 550 and 850 g VOC/J?; the average is
approximately 695 g VOC/£.4 As discussed in Chapter 2, a
separate category for precoats is not necessary; therefore,
none of the options contain precoat categories.
Since primer sealers are sometimes used as bare metal
coatings, the primer sealer limits of the options (discussed
below) were used to estimate the emissions reductions from
precoats. The Option 1 and 2 limit of 550 g VOC/£ would
result in about a 60 percent reduction in VOC emissions from
the average precoat; the Option 3 limit of 420 g VOC/f would
result in about an 80 percent reduction.
Conventional primer/primer surfacers contain between
550 and 850 g VOC/£; the average is approximately 685 g
VOC/£.5 The Option 1 limit of 550 g VOC/£ would result in
about a 55 percent reduction in VOC emissions from
conventional primer/primer surfacers; the Option 2 limit of
455 g VOC/t would result in about a 70 percent reduction; the
Option 3 limit of 335 g VOC/£ would result in about an 85
percent reduction.
Conventional primer sealers typically contain between 600
and 805 g VOC/-?; the average is approximately 755 g VOC/£.6
The Option 1 and 2 limit of 550 g VOC/f would result in about
3-4
-------
a 75 percent reduction in VOC emissions from conventional
primer sealers; the Option 3 limit of 420 g VOC/t would result
in about a 90 percent reduction.
As discussed in Chapter 2, topcoats are typically applied as
a single coating, or a 2-stage (basecoat/clearcoat) or 3-stage
(basecoat/midcoat/clearcoat) system. The VOC content of a
multi-stage topcoat is estimated by the following equation:
M
VOCbc + T" VOCmci + 2(VOCcc)
voc - • • - iM°
M + 3
where:
VOC multi = voc content of a multi-stage topcoat,
VOC content of the basecoat,
VOCmc. = VOC content of the midcoat(s),
VOCCC = VOC content of the clearcoat, g/£; and
M = Number of midcoats.
This equation is used because the basecoat is approximately
one-third, and the clearcoat two-thirds, of the total film
thickness of a 2-stage topcoat system. The basecoat and
midcoat each are approximately one-quarter, and the clearcoat
one-half, of the total film thickness of a 3-stage topcoat
system. Additional midcoats present in topcoats of more than
three stages are included in the middle term of the numerator.
The VOC contents of conventional refinish topcoats range
from 550 to 805 g VOC/(.7 The average VOC contents of the
different topcoat types are presented in Table 3-1. The
emission reductions from conventional topcoats that would
result from a 600 g VOC/f limit range from about 70 percent
for lacquers to about 40 percent for all other topcoats. The
625 g VOC/t limit for 3-stage topcoats included in Option 1
would result in about a 30 percent reduction from conventional
coatings.
3-5
-------
The use of topcoats with VOC contents below the Option 3
limits reportedly can result in inferior color-match. Coating
manufacturers contend that the use of such coatings could
actually increase VOC emissions because painters could be
forced to refinish substantially larger portions of an
automobile in order to blend the refinished area into the
existing finish.
3.3 EXISTING STATE REGULATIONS
A number of States containing ozone nonattainment areas
have already adopted rules for automobile refinishing. A
summary of these regulations is presented in Table 3-2. The
following subsections briefly describe the regulations in
these States.
3.3.1 New Jersey
The New Jersey regulation applies to the entire State,
and specifies the maximum allowable VOC emissions per volume
of coating. No requirements are specified regarding surface
preparation or equipment cleaning operations.8
3.3.2 New York City
The New York City Metropolitan Area regulation applies to
the five boroughs of New York City and four surrounding
counties. The regulation limits the VOC content of automobile
refinish coatings applied.9
3.3.3 Texas
In Texas, automobile refinishing is regulated under a
rule covering several types of surface coating processes. The
Texas regulation limits the VOC content of coatings and
surface preparation products in all nonattainment areas. Body
shops in these areas are also required to use enclosed gun
cleaners.10
3.3.4 California
Several California air .quality districts have adopted
rules for automobile refinishing, including the Bay Area,
South Coast, Ventura, San Joaquin, Santa Barbara, and Mojave.
Others, such as San Diego and Sacramento, have rules in
development. With minor differences, these rules contain the
3-6
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TABLE 3-2. EXISTING REGULATIONS
Area 1995 coating VOC limits
(g/l)
New Jersey9- Basecoat: 720
Clearcoat: 530
Others: 600
Texas13 Pretreatment: 780
Precoat: 660
Primers: 600
Primer sealer: 720
Topcoat: 600
3-stage topcoat: 625
Specialty coating: 840
New York City Repair/touchup: 745
Overall (full job): 600
California Air Pretreatment: 420
Resources Precoat: 420
Board Primer/primer surfacer: 250
(CARB)c/d Primer sealer: 335
Topcoat: 455
Metallic/Iridescent
topcoat: 540
Specialty coating: 840
aRegulation applies to entire state.
^Regulation applies in nonattainment areas only.
GMost air quality management districts in California are
expected to adopt rules
with these requirements by January 1995.
•3-CARB recommends lower limits for mobile equipment.
3-7
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same requirements determined to be the "best available"
control technology by GARB,11 including VOC content limits for
coatings and surface preparation products, and spray gun
efficiency and cleaning requirements.
3-8
-------
3.4 REFERENCES
1. Memorandum from Campbell, D.L., Radian Corporation, to
Ducey, E. EPA/CPB. February 28, 1991. Summary of
Coating Manufacturer's Survey Responses -- Automobile
Refinishing CTG.
2. State of California Air Resources Board. Determination
of Reasonably Available Control Technology and Best
Available Retrofit Control Technology for Automobile
Refinishing Operations. January 8, 1991.
3. National Paint and Coatings Association. NPCA Automotive
Refinish Coalition's Estimates of 1990 National Baseline
VOC Emissions from the Automotive Refinish Industry.
Washington, DC. March 1992. 6 pp.
4. Ref. 3.
5. Ref. 3.
6. Ref. 3.
7. Ref. 3.
8. New Jersey State Department of Environmental Protection
and Energy. Control and Prohibition of Air Pollution by
Volatile Organic Compounds. Title 7, Chapter 27. New
Jersey. State Department of Environmental Protection and
Energy. January 28, 1992.
9. New York State Department of Environmental Conservation.
An Evaluation of Alternatives to Reduce Emissions from
Automobile Refinishing in New York, New York. New York
State Department of Environmental Conservation.
August 1987.
10. Texas Natural Resources Conservation Commission. Control
of Air Pollution from Volatile Organic Compounds.
Regulation 5, Chapter 115, Subchapter E. Austin, Texas.
November 10, 1993.
11. Ref. 2.
3-9
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4.0 BASELINE EMISSIONS AND EMISSIONS REDUCTIONS
This chapter presents estimates of the VOC emissions and
emissions reductions from the use of low-VOC coatings. Since
some States have already developed automobile refinish rules,
1995 emissions were used as the "baseline" from which
emissions reductions were measured. Considering the
reductions already achieved by State rules, estimates of
baseline VOC emissions are presented in Table 4-1, along with
estimates of the reductions achievable using low-VOC coatings.
4.1 COATING APPLICATION
4.1.1 Baseline Volatile Organic Compound Emissions from
Coating Applications
Estimates of 1995 VOC emissions from coating applications
were based on 1988 coating usage and emissions estimates
provided by coating manufacturers^'2. The amount of coating
required for a refinish job ultimately depends on the solids
content of the coating. The amount of coating solids
projected for application in 1995 is presented in Table 4-2.
The relationship between the VOC (predominantly solvent)
and solids in a solventborne coating was approximated using
the following equation:
Vs = 1 - (VOCC / d) (4.1)
where:
Vs = Volume solids content of coating (fraction);
VOCC = Solvent (VOC) content of coating (g/£); and
d = Density of solvent
4-1
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m
m
rt
in in **
H m CNJ . O t>
H H
0*0 o o o o :
*j< o co c* o\
0 n rH CS
H fl C^
rH rH
O O O O O O
VD C"** 03 in ro rn
r~ CO rH VD O O
CO ^*
CQ
rt
0)
nS
4J
G
0)
•H
-U CQ
4-) fC
nJ d)
0 rt
G
G
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4J G
•H t) -H
Sn CJ rt rt
Q) -H C71 JJ
CO J«J G G -U
0) O O G
hj >H CQ «W -H
rt -H rt CQ
CD 0 Q) rt
-------
TABLE 4-2. 1995 COATING SOLIDS USE
Coating solids
Coating category use
(103 l/yr)
Primers
Pretreatment wash primer 260
Precoat 150
Primer/primer surfacer 3,940
Primer sealer 1,100
Topcoats
Single stage
Lacquer 910
Enamel 4,920
Basecoat 2,990
Clearcoat 13,700
Specialty 40
Total 28,010
4-3
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The amount of coating solids applied in the United States
was estimated by the following equation:
Cs = Cc * Vs (4.2)
where:
Cs = Liters of coating solids applied in the United
States;
Cc = Liters of coatings applied in the United States;
and
Vs = Volume solids content of coating (fraction).
The amount of coating solids applied in a particular area of
the United States is assumed to be a function of the
population of that area, and was estimated by the following
equation:
Csa = Cs * (Pa / PUS) <4-3)
where:
csa = Liters of coating solids applied in area;
Cg = Liters of coating solids applied in the United
States;
Pa = Population of area; and
PUS - U.S. population.
Census data for 1990 were used in this document to estimate
1995 populations. The U.S. population in 1990 was
approximately 248,710,000.3 Population data for nonattainment
areas were obtained from a 1994 EPA document on nonattainment
area designations.4
By rearranging equation 4.2, the amount of coating used in
a particular area ("area coating use") can be estimated by
dividing the amount of coating solids applied in the area by
the coating VOC content that is typical or, in the case of
regulated areas, required in the area. Area coating use was
4-4
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estimated by the following equation:
Cca = Csa / Vsa (4.4)
where:
Cca = Area coating use (t/yr);
Csa = Liters of coating solids applied in area; and
Vsa = Volume solids content of coating (a function of
the presence and stringency of the area's
applicable rule) expressed as a fraction.
The VOC emissions in an area from coating application were
estimated using the following equation:
Et = (cca * VOCC) / 106 (4.5)
where:
Et = Area coating application emissions
(megagrams/yr);
Cca = Area coating use (£/yr);
VOCC = VOC content of coating (g/£); and
10^ = Grams per megagram.
Equations 4.1 through 4.5 were used for each coating category
to estimate baseline VOC emissions and emissions reductions.
4.1.2 Reduction of Volatile Organic Compound Emissions from
Coating Applications
As shown in Table 4-1, Option 1 reduces baseline emissions
by about 32,470 megagrams per year (Mg/yr), or 37 percent;
Option 2 reduces the baseline by about 34,520 Mg/yr, or 39
percent; and Option 3 reduces the baseline by about 36,820
Mg/yr, or 42 percent.
4-5
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4 .2 REFERENCES
1. National Paint and Coatings Association. NPCA Automotive
Refinish Coalition's Estimates of 1990 National Baseline
VOC Emissions from the Automotive Refinish Industry.
Washington, DC.' March 1992.
2. Letter from Inglis, R., BASF Corporation, to Sullivan,
J.W., Radian Corporation. March 8, 1993. Emission
estimates for the automobile refinish industry.
3. U. S. Bureau of the Census. Statistical Abstract of the
United States: 1991 (llth edition). Washington, DC.
1991. p. 7.
4. U. S. Environmental Protection Agency, Office of Air
Quality Planning and Standards. Ozone and Carbon Monoxide
Areas Designated Nonattainment. Research Triangle Park,
NC. August 15, 1994.
4-6
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5.0 COST IMPACTS
This chapter discusses the methods and assumptions used
to estimate the cost impacts of implementing the control
options described in Chapter 3, Sections 5.1, 5.2, and 5.3
present estimates of the costs that coating manufacturers,
distributors., and body shops, respectively, would incur from
the implementation of the coating options. Cost effectiveness
of the control options are discussed in Section 5.4.
5.1 COSTS TO COATING MANUFACTURERS
Coating manufacturers will incur costs from the
implementation of the VOC limits of the coating options due to
process modifications and training. Research and development
(R&D) costs associated with formulating low-VOC coatings were
not considered, since these costs have generally already been
forced by State regulations.
5.1.1 Process Modifications
Implementation of the coating options will require
manufacturers to modify production facilities. Transition to
coatings compliant with Options 1 and 2 is estimated to cost
about $10 million. Most of this cost would be to purchase
pumping and mixing equipment that will process higher-solids
coatings.1 Although solventborne coatings are available that
meet the primer and primer sealer VOC limits of Option 3,
according to coating manufacturers these limits would likely
be met using waterborne coatings because of difficulties in
the application of high-solids coatings, such as the
difficulty in applying a thin coat of primer sealer.
Modifications required to produce waterborne coatings will
cost about $73 million, primarily to upgrade process equipment
5-1
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from carbon steel to corrosion resistant materials.2-5
5.1.2 Training Costs
Implementation of the coating options would likely
require that manufacturers teach their sales representatives,
technicians/trainers, district/other managers, marketing
personnel, and "product specialists" (personnel who provide
the interface between R&D and marketing departments) to use
the new coatings. It was estimated that approximately
2,500 employees would require one day of training.6 The cost
for each was estimated at $425, including travel, lodging, and
wages.7 Training costs for all options are assumed to be
equal.
5.1.3 Annual Costs to Coating Manufacturers
Process modification and training costs were annualized
over 10 years at an interest rate of 7 percent. These costs .
are presented in Table 5-1.
5.2 COSTS TO DISTRIBUTORS
Coating distributors must be trained in order to provide
essential services (e.g., mixing of topcoat colors,
troubleshooting advice, general product information) to their
customers. An estimated 4,450 distributors would have a
representative attend a l-day training seminar. The total
cost for each distributor was estimated to be $425, including
travel, lodging and wages.8'9
The training costs for distributors were also annualized
over 10 years at an interest rate of 7 percent, and are
presented in Table 5-1.
5.3 COSTS TO BODY SHOPS
Costs incurred by shops may include painter retraining,
infrared heating system purchase/operation, and productivity
losses. Shops would likely incur only training costs if the
VOC limits of Option 1 were implemented, while Options 2 and 3
may trigger all of the costs mentioned above.
5.3.1 Training costs. Because compliant.coatings may
mix, spray, and dry differently than noncompliant coatings,
painters must be retrained in these areas. It was estimated
5-2
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Table 5-1. ANNUAL COSTS OF CONTROL TECHNIQUES (103 $)
Option 1 Option 2 Option 3
Manufacturer costs
Process 1,420 1,420 10,380
modifications
Training 150 150 150
Distributor training 270 270 270
costs
Body shop costs
Training 2,690 2,690 2,690
Heating systems 0_ 20,890 20, 890
Total annual costs 4*530 25,420 34,380
5-3
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that 44,500 painters will require training. Coating
manufacturers, who will provide the training, estimate that
the requisite 8 hours of instruction can be scheduled (during
weekends or evenings) with no loss of shop revenue.10,11
Because training may require overtime, it was assumed
that shops will reimburse painters with overtime wages of $12
per hour (1.5 times the normal hourly wage) and the cost of
two meals ($15),12 It was also assumed that no travel costs
will be incurred; training will be made available locally.13"
14 The 8-hour course will be offered at no charge by coating
manufacturers.15'16
5.3.2 Infrared Heating System Costs. As discussed
earlier, coatings.compliant with Options 2 and 3 may require
supplementary heat because their drying characteristics are
affected by ambient conditions. Without supplementary heating
they reportedly can require up to two days to dry.17 To
minimize productivity losses, shops may purchase heating
systems to use during periods of adverse ambient conditions.
Two moderate-to-large heaters were assumed to be
necessary at shops. Most shops already own one heating
system, so the costs presented in this document are for the
purchase and operation of an additional heating system at
44,500 shops. Heating systems are estimated to cost $2,120
each, and are used on approximately 25 percent of refinish
jobs.18,19
5.3.3 Potential Productivity Losses
Coatings that meet the limits of Options 2 and 3 may
affect shop productivity because of their longer drying times.
The following is a discussion of the potential effects on
productivity of the various coatings.
Primer surfacers. Option 2 and 3 primer surfacers
may affect shop productivity because they dry slower than
conventional coatings. If supplemental heating is not used
to speed drying, productivity losses may occur in some
geographical areas if these surfacers are used. In humid,
cool conditions, waterborne surfacers are reported to dry
5-4
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slowly, and drying times of up to two days under such
conditions are reportedly common in the absence of
supplementary heating.20
The impacts on productivity that would be caused by use
of Option 2 and 3 surfacers are highly variable and
impossible to quantify on a nationwide basis. For instance, a
substantial number of shops would not lose any productivity
because they would compensate for increased drying time by
performing other work while the surfacers are drying, and by
scheduling work flow through the shop differently. However,
many shops cannot merely work on other refinish jobs while
jobs with primer surfacer coats are drying because these shops
do not have adequate floor space. Shops may need to use
drying equipment, such as infrared heating systems, to reduce
drying time. Shops that use infrared heating systems to
accelerate drying may still lose up to 15 minutes per job
positioning the heating systems.21 It should be noted that
the use of heating systems may not totally eliminate
productivity losses.
Primer sealers. No productivity losses are anticipated
from the primer sealers of any option. Shop employees in the
SCAQMD reported that primer sealers equivalent to Option 3 dry
as quickly as conventional primer sealers.22'28
Topcoats. Coating manufacturers report that low-VOC
topcoats do not dry significantly slower than conventional
topcoats and, consequently, no productivity losses are
expected from the use of low-VOC topcoats.29 Manufacturers
claim, however, that shops without spray booths that use
lacquer topcoats will lose productivity when switching to
compliant topcoats. The longer drying times of compliant
topcoats leave the wet surface exposed to airborne
contaminants. Manufacturers maintain that shops must expend
more labor during polishing to remove the additional
contamination.30
Costs for shops without spray booths that use lacquers
have not been included in this document, primarily because
5-5
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lacquer use for automobile refinishing has steadily dropped
over the last few years, a trend which would likely continue
even in the absence regulatory action. In 1988 and 1993,
lacquers were used on 25 percent and 14 percent of refinish
jobs, respectively.31'32 Furthermore, there is evidence that
most shops without spray booths are already using conventional
enamels or urethanes, which, as mentioned previously, do not
dry significantly faster than low-VOC topcoats.
5.3.4 Annual Costs to Shops
The capital costs of heating systems and training were
armualized over 10 years at an interest rate of 7 percent.
These annual costs are presented in Table 5-1.
5.4 COST EFFECTIVENESS
Average cost effectiveness is the cost to reduce VOC
emissions by 1 megagram. Average cost effectiveness values
were calculated by dividing annual costs by annual emission
reductions. The annual costs of the coating options include
costs for process modifications, manufacturer, distributor,
and body shop training, and infrared heating systems (Options
2 and 3). The average cost effectiveness of Options 1 through
3 are $140, $740, and $940 per megagram, respectively.
Incremental cost effectiveness is the cost to achieve the
incremental emission reductions from implementing one option
instead of another. The cost for the additional emission
reductions achieved by Option 2 over Option 1 is about $10,100
per megagram. The incremental cost effectiveness of
implementing Option 3 (instead of Option 2) is about $3,900
per megagram.
5-6
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5.5 REFERENCES
1. Telecon. Sullivan, J. W., Radian Corporation, with
Schultz, K. R., E.I. du Pont de Nemours & Company, Inc.
March 16, 1993. Costs of regulation.
2. Ref. 1.
3. Meeting Summary from Sullivan, J. W., Radian Corporation,
to Sell, J., National Paint and Coatings Association, et.
al. January 8, 1993. National Paint and Coatings
Association Automotive Refinish Coalition views on future
Federal regulation.
4. Letter from Schultz, K. R., E.I. du Pont de Nemours &
Company, Inc., to Sullivan, J. W., Radian Corporation.
June 18, 1993. Cost estimates of plant modifications
necessary to produce waterborne coatings.
5. Sullivan, J. W., Radian Corporation. September 13, 1993.
Calculation of costs to manufacture waterborne primers.
6. Meeting Summary from Sullivan, J. W., Radian Corporation,
to Sell, J., National Paint and Coatings Association, et.
al. Model shops and costs of Federal regulation.
July 9, 1993.
7. Letter from Sell, J., National Paint and Coatings
Association, to Ducey, E., EPA/CPB. June 3, 1993. Costs
of Federal regulation.
8. Ref. 7.
9. Letter from Carragher, R., Automotive Service Industry
Association, to Ducey, E., EPA/CPB. May 10, 1993.
Comments on training for the automotive refinishing
industry rulemaking.
10. Ref. 7
11. Ref. 9.
12. Ref. 9.
13. Ref. 7.
14. Ref. 9.
15. Ref. 9. • . .
16. Telecon. Burk, D. G., Radian Corporation, with
Sieradzki, R., AKZO Coatings, Inc. March 25, 1993.
Painter retraining.
5-7
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17. Memorandum from Sell, J., National Paint and Coatings
Association, to Sullivan, J. W., Radian Corporation.
August 23, 1993. Additional background information
concerning the Automotive Refinish Background Information
Document.
18. Telecon. Sullivan, J. W., Radian Corporation, with
Gregory, D. April 1, 1993. Edwin Trisk heating lamps.
19. Telecon. Sullivan, J. W.,Radian Corporation, with
Hutchins, J. March 22, 1993. Infratech curing systems.
20. Ref. 17.
21. Ref. 17.
22. Sullivan, J. W., Radian Corporation. Site visit at R. B.
Paint and Body Center. Sante Fe Springs, CA. prepared
for Morris, M., EPA/CPB. August 25, 1993.
23. Sullivan, J. W., Radian Corporation. Site visit at One
Day Paint and Body, Anaheim, CA. Prepared for Morris,
M., EPA/CPB. August 25, 1993.
24. Sullivan, J. W., Radian Corporation. Site visit at Lee's
Body Works. Sante Fe Springs, CA. Prepared for Morris,
M., EPA/CPB. August 25, 1993.
25. Sullivan, J. W., Radian Corporation. Site visit at Maaco
Auto Painting. Sante Fe Springs, CA. Prepared for
Morris, M., EPA/CPB. August 25, 1993.
26. Sullivan J. W., Radian Corporation. Site visit at House
of Imports. Buena Park, CA. Prepared for Morris, M.,
EPA/CPB. August 25, 1993.
27. Sullivan, J. W., Radian Corporation. Site visit at
Camenita Collision Center. Sante Fe Springs, CA.
Prepared for Morris, M., EPA/CPB. August 25, 1993.
28. Sullivan, J. W., Radian Corporation. Site visit at Dave
Salas Metric's Auto Body Shop. Sante Fe Springs, CA.
August 25, 1993.
29. Ref. 6.
30. Ref. 6. [
31. Body Shop Business. 1990 Annual Industry Profile. 9_;49.
June 1990.
32. Babcox Publications. 1993 Annual Industry Profile. June
1993. p.48.
5-8
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TECHNICAL REPORT DATA
(Please read Instructions on reverse before completing)
i. REPORT NO.
EPA-453/D-95-005a
3. RECIPIENT'S ACCESSION NO.
4. TITLE AND SUBTITLE
Volatile Organic Compound Emissions from
Automobile Refinishing - Background Information
for Proposed Standards
5. REPORT DATE
August 1995
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
U.S. Environmental Protection Agency
Office of Air Quality Planning and Standards
Technical Support Division
Research Triangle Park, NC 27711
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
12. SPONSORING AGENCY NAME AND ADDRESS
U.S. Environmental Protection Agency
Office of Air Quality Planning and Standards
Technical Support Division
Research Triangle Park, NC 27711
13. TYPE OF REPORT AND PERIOD COVERED
Draft
14. SPONSORING AGENCY CODE
15. SUPPLEMENTARY NOTES
16. ABSTRACT
A draft rule for the regulation of volatile organic compounds (VOC) from automobile refinishing is
being proposed under the authority of Section 183(e) of the Clean Air Act. This document contains
information on the automobile refmish industry, and presents control options and their associated
environmental and cost impacts.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b. IDENTIFIERS/OPEN ENDED TERMS
c. COSATI Field/Group
Air Pollution
Volatile Organic Compounds
Automobile Refinishing
Consumer and Commercial Products
18. DISTRIBUTION STATEMENT
Release Unlimited
19. SECURITY CLASS (Report)
Unclassified
21. NO. OF PAGES
58
20. SECURITY CLASS (Page)
Unclassified
22. PRICE
EPA Form 2220-1 (Rev. 4-77) PREVIOUS EDITION IS OBSOLETE
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