903R83007
VOLATILE ORGANIC COMPOUND  EMISSION CONTROLS
  FOR THE AUTOMOBILE  REFINISHING  INDUSTRY
                    by

         PEDCo Environmental,  Inc.
            1006 N.  Bowen  Road
          Arlington,  Texas   76012
          Contract No.  68-02-3512
             Task Order No.  43
              Project Officer
               Eileen Glenn
   U.S. ENVIRONMENTAL PROTECTION  AGENCY
                REGION III
     PHILADELPHIA,  PENNSYLVANIA  19106
               November 1983

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                                   CONTENTS



                                                                         Page

Summary                                                                   iii

1.    Introduction                                                           1

     1.1  Source description and type of VOC emissions                      1

2.    Emission Control  Techniques                                            4

     2.1  Add-on controls                                                   4
     2.2  Lower VOC content coatings                                        4
     2.3  Improved transfer efficiency                                      5
     2.4  Other controls                                                    5

3.    Cost Analysis                                                          7

     3.1  Parameters for add-on controls                                    7
     3.2  Incineration                                                      7
     3.3  Carbon adsorption                                                 8
     3.4  Cost-effectiveness                                                9

4.    Regulatory Analysis                                                   10

References                                                                 11

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                                    SUMMARY



     This report presents an evaluation of the prospect of controlling VOC

emissions from automobile refinishing shops.   An industry estimate indicates

that the Philadelphia area has approximately 2000 such refinishing shops, and

these sources are believed to emit a total of about 2000 tons of volatile

organic compounds (VOC) per year.   A survey of different yellow pages in the

AQCR, however, indicated only 744 automobile refinishers.

     Exceptionally large automobile refinishing shops may emit 10 to 20 tons

of VOC per year.   Although most automobile refinishing is done in conjunction

with body repair work that involves repainting only part of a car, body repair

shops also routinely repaint entire automobiles; in fact,  several nationwide

chains specialize in this service.

     Surface preparation and painting are both sources of VOC emissions.  The

former includes first .washing and/or steam cleaning the car, followed by

sanding, solvent cleaning, and applying a primer.  Solvent cleaning entails

hand-wiping the surface.  The primer and paint are applied with hand-held,

compressed-air, spray guns.

     Total VOC emissions from painting an entire automobile average about 12.2

pounds.  During the busiest season, a large custom shop will paint about 30

cars per week, and this type of shop emits an estimated 6.3 tons of VOC per

year.  The rate of VOC emissions from establishments that specialize in body

repair work is much lower.  A large shop that specializes in low-cost painting

can paint up to 20 cars per day, and the estimated VOC emission rate for this

type of shop is 14 tons per year.

     The use of incineration, catalytic incineration, and carbon adsorption

control systems is not practical for automobile refinishing shops.  The

paints, paint thinners, and primers used in these shops contain xylene, tolu-

ene, and petroleum distillate, and OSHA regulations limit the concentrations

of these VOCs in ambient air to 100 ppm.  The control device would require

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large volumes of dilution air, and the cost of heating this large air volume

rules out incineration on economic grounds.  Inasmuch as paint solids render

catalytic incineration ineffective, this control  is automatically eliminated.

Carbon adsorption is impractical  because of the diversity of VOC species in

the process exhaust.  An additional problem is that most VOC emissions occur

during or shortly after application of the finish,  and any control  device

would have to be sized to handle this maximum emission rate.   For this reason,

the control device would be operating far below its rated capacity most of the

time and thus be greatly underutilized.

     The reduction of VOC emissions through the use of water-based coatings or

coatings with a higher solids content and the possibility of more efficient

application techniques were examined.  Water-based coatings and those with

higher solids content apparently do not produce a finish equivalent to that of

a new car.  One nationwide chain has evaluated and is continuing to evaluate

these possibilities with an eye toward reducing material costs.

     There is no proposed draft regulation at this time, but the Philadelphia

Air Quality Control Region should continue to monitor progress in the areas of

improved transfer efficiency and new product development to determine if and

when new regulations might become feasible.
                                       IV

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                               1.   INTRODUCTION

     Over the past several years EPA's Office of Air Quality Planning and
Standards (OAQPS) has developed a series of Control  Techniques Guidelines
(CTGs) for volatile organic compounds (VOC) to assist state and local agencies
in the development of regulations for VOC control.   Although these CTGs cover
major VOC source categories from an overall nationwide perspective, several
VOC source categories that are not covered by CTG documents are major contri-
butors to the ozone problem within given areas.
     Air pollution control agencies in the Philadelphia Air Quality Control
Region (AQCR) have requested guidance in determining whether VOC controls are
available for non-CTG sources.  These agencies desire information that may
assist them in developing appropriate regulations.   One such VOC source cate-
gory to be investigated is automobile refinishing.   An industry estimate
indicates that there are 2000 automobile refinishers in the Philadelphia area
(M. Martino, Maaco Enterprises, Inc., personal communication, February 8,
1983); however, a survey of the Philadelphia, Camden, New Jersey, and Wil-
mington, Delaware, yellow pages indicated 451, 193,  and 99 automobile refin-
ishers, respectively, for a total of 744 automobile refinishers in the Phila-
delphia area.

1.1  SOURCE DESCRIPTION AND TYPES OF VOC EMISSIONS
     Most automobile refinishing is done in conjunction with body repair work,
which usually involves refinishing only part of the car and carefully matching
the color of the new paint with that of the existing paint.  Several nation-
wide chains,-however, specialize in repainting entire automobiles.
     Surface preparation prior to painting begins with washing or steam-clean-
ing the automobile.  Except for the lowest-priced automobile painting jobs,
additional surface preparation may include light sanding and hand-wiping with
solvent to remove oil, wax, and grease.  About one quart of solvent is used  to

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clean a typical car.   The next step in the process is to mask off the parts of
the car that are not to be painted.  Primer is then applied to the areas to be
refinished with a hand-held, compressed-air, spray gun.   One to two quarts of
primer will cover an entire automobile.
     Painting the car requires about one gallon of paint, which may be acrylic
lacquer, acrylic enamel, alkyd enamel, or polyurethane enamel.   Each gallon of
acrylic lacquer requires 5 to 7 quarts of thinner; acrylic enamel, 2 quarts;
alkyd enamel, 1 to 2 quarts; and polyurethane enamel, up to 1 quart (J.  Hill,
Hill's Paint and Body Shop, personal communication, April 15, 1983).   A gloss
hardener is sometimes used on enamel to speed up drying, about one pint per
gallon of paint.  Because hardener is expensive, however, shops try to avoid
its use.  For example, hardener normally will not be used if overnight drying
is convenient.   Some larger shops use bake ovens to speed up drying.
     Three to six coats of paint are applied with a hand-held, compressed air,
spray gun.   If lacquer is used, light sanding is required after each coat;
consequently, lacquer finishes are very expensive.  Lacquer coatings can be
spot-repaired,  however, which reduces the amount of repainting necessary.
Laccuer also dries faster than enamel, which is advantageous when shop floor
space is limited.  The faster drying also makes lacquer coatings less likely
to pick up dust and dirt from the shop environment during drying.   For these
reasons, custom shops and those that do a high-volume business often use
lacquer despite its extra cost.
     The VOC content of lacquers and enamels ranges between 4.5 and 5 pounds
per gallon.1  The solvents include toluene, xylene, petroleum distillate,  and
mixtures of aliphatic ketones, alcohols, and esters.  The solvent used for
cleaning is primarily a light petroleum distillate.  Primer and paint thinner
solvents are essentially the same as paint solvents.
     The VOC emissions from painting a single automobile are estimated to be
12.2 pounds (5.55 kilograms).  This estimate is based on the following usage:
     1.   One gallon of paint containing 4.8 pounds (2.2 kilograms) of
          VOC;
     2.   One quart of degreasing solvent containing 1.8 pounds (0.8
          kilograms) of VOC (density equal to No. 1 fuel oil);
     3.   Two quarts of sealant containing 2.4 pounds (1.1 kilograms) of
          VOC (VOC content equivalent to the paint); and

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     4.    Two quarts of thinner containing 3.3 pounds (1.5 kilograms) of
          VOC (density equivalent to acetone).

     During the busiest season, a large custom painter will  paint six cars per

day or 30 cars per week.   (Automobile refinishing shops typically operate just

over 8 hours a day, Monday through Friday.)  This corresponds to an hourly

emission rate of 9 pounds (4 kilograms) or a daily emission  rate of 73 pounds

(33 kilograms).  The estimated average annual emission rate  is 6.3 tons (5.7

megagrams).

     A large painting specialty shop paints a maximum of 20  cars per day.   If

the shop uses only paint and thinner, it will emit 8.7 pounds of VOC per car.

This corresponds to a VOC emission rate of 20 pounds (9.2 kilograms) per hour

or 160 pounds (73 kilograms) per day.  The estimated annual  VOC emission rate

frorr these shops is 14 tons (13 megagrams).

     A typical body repair shop has a much lower emission rate.  The estimated

emission rate for such a shop is 1 ton (0.9 megagram) per year.

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                        2.   EMISSION CONTROL TECHNIQUES



     The control  of VOC emissions from automotive surface coating operations

is complicated by two factors:   (1) most of the emissions occur during and

shortly after application of the coating; and (2) the coatings contain VOCs

such as toluene,  xylene, and petroleum distillate and OSHA regulations limit

concentrations of these compounds in ambient air to 100 ppm.   Meeting the OSHA

standard requires the dilution of the VOC-containing streams  with large vol-

umes, of air.



2.1  ADD-ON CONTROLS


     Incineration is technically feasible, but it is impractical  because of

the large quantity of dilution air that must be heated to around 816°C

(1500°F).  Catalytic incineration is impractical because solid particles from

the paint accumulate on the catalyst surface and render it inactive.   Carbon

adsorption is not a feasible control because a huge unit would be required to

control the large volumes of VOCs that are emitted at very low concentrations

from the process.  Also, it would be difficult (if not impossible) to strip

high-boiling-solvent components from the carbon bed.  Water-soluble VOC spe-

cies, such as acetone and isopropanol cannot be easily separated from con-

densate if steam is used to regenerate the carbon.   Thus, extensive paint

reformulation would be necessary, even if a system that is not prohibitively

large could be designed.  The control efficiency of a carbon  adsorber would be

severely limited because the exhaust stream would have a VOC  content of 10 to

25 ppm compared with a 50 to 100 ppm VOC concentration in the inlet stream.



2.2  LOWER VOC CONTENT COATINGS


     General Motors uses water-based coatings in its assembly lines,  but a

1977 report indicates that no satisfactory water-based coatings have been

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developed for the automotive refinishing market.2  Apparently, this is still
the case.
     Since almost all existing coatings are thinned with solvents prior to
their application, the use of these coatings or modifications of these coat-
ings with higher solids content does not appear to be promising.   The goal of
the automotive refinishing industry is to produce a finish with an appearance
equivalent to that of a new car; anything less is unmarketable.

2.3  OTHER CONTROLS
     The use of enclosed booths for automobile painting could reduce the
capital costs of VOC control.  Because less dilution of air would be needed, a
smaller-capacity control device, such as a carbon adsorber or incinerator,
could be used.  Operating costs also would be lowered, but some of this sav-
ings, would be offset by the capital and operating costs of the booth.  Costs
analyses show that add-on controls are not cost-effective, even if a favorable
exact VOC dilution is assumed.   The OSHA upper limit of 100 ppm would be
attainable with enclosed booths, but most automobile refinishing shops empha-
size body repair work and painting is only a necessary secondary activity.
Enclosed booths dedicated to painting would tie up much needed floor space in
body shops when space is often limited.  Increasing the amount of space in
such shops would mean additional operating costs as well as the costs of VOC
control devices.
     The automobile refinishing industry has experimented with electrostatic
sprciy guns, but none of them have worked ,as well as the conventional hand-
held, compressed-air spray gun (M. Martino, Maaco Enterprise, Inc., personal
communication, April 20, 1983).  Also, it takes 2.5 to 3 times longer to paint
the car with an electrostatic spray gun.

2.4  IMPROVED TRANSFER EFFICIENCY
     Transfer efficiency is defined as the percent of the coating emitted from
an applicator that actually coats the surface.  In the wood furniture coating
industry, a typical transfer efficiency is 40 percent.3  For the application
of paints on the assembly line:  electrostatic spraying had transfer efficien-
cies as high as 93 percent; airless non-electrostatic spraying had transfer

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efficiencies of 44 percent; air non-electrostatic spraying had transfer effi-

ciencies of 37 percent, and water-borne coating application had transfer

efficiencies of 30 percent (A.  Rawaka, South Coast Air Quality Managment

District, personal communication, October 24, 1983).   No transfer efficiency

estimates for automobile refinishing were available.

     Paint spray guns have been developed that promise to improve transfer

efficiency4 and better transfer efficiency would reduce VOC emissions by

reducing paint consumption.  Maaco Enterprises, Inc., a nationwide chain of

automobile painting and body repair shops, has evaluated and worked with

different types of spray guns and spraying techniques with an eye toward im-

proving transfer efficiency as a means of reducing material costs (M. Martino,

Maaco Enterprises, Inc., personal communication, April 20, 1983).  In their

opinion, however, these new paint spray guns do not produce a finish of ac-

ceptable quality.

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                               3.   COST ANALYSIS



     The cost of the material for a $500 to $750 automobile paint job is about

$200 (J. Hill, Hill's Paint and Body Shop, personal communication, April 15,

1983).   The remainder covers labor, overhead, and profit.   About $125 of the

$20C is for coating materials; the rest is for tape, sandpaper, and cleanup

supplies.   The material cost associated with a $79.95 budget repaint job is

aboit $20.00 (B. Bennett, Earl Scheib, Inc., personal communication, March 23,

1983).   Obviously there is considerable incentive to reduce material costs

through improved transfer efficiency.



3.1  PARAMETERS FOR ADD-ON CONTROLS

     Estimates for control costs represent a large custom shop capable of

painting 6 cars a day or 30 cars a week.   Estimated VOC emissions amount to

12.2 pounds per car, or 6.3 tons per year.  Assuming that the control device

would need to process 3000 scfm of VOC-laden air and the average molecular

weight of the VOC equals that of toluene, this would correspond to the eva-

poration of 4.46 pounds per hour of VOC diluted to 100 ppm.   This is equal to

the evaporation of 2 quarts of solvent over a 32-minute period.  To accomplish

this, the shop would have to schedule operations so that only one paint,

degreasing solvent, or sealant spraying operation took place at any one time.



3.2  INCINERATION

     Two cases are considered.  In the first case, the VOC is diluted with air

to 130 ppm, incinerated at 816°C (1500°F), and the exhaust gases are vented.

In the second case, the exhaust gases are used to preheat the incoming air-VOC

stream.  The latter would reduce fuel  requirements by 54 percent, but capital

costs would double.

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     Estimated capital  costs are $45,000 for the incinerator and $90,000 for
the incinerator-preheater combination.   Installation costs are equal to capi-
tal costs.   Capital-related annual costs are as follows:   (1) a capital re-
covery factor of 14.67 percent of the total capital investment, based on a
12-year equipment life and a 10 percent interest rate5; (2) property taxes and
insurance at 4 percent of total cpaital costs; and (3) operating and mainten-
ance costs at 4.75 percent of total capital costs.   Assuming that OSHA stand-
ards could be met by diluting the 12.2 pounds of VOC emitted while painting an
automobile and that the average molecular weight of the VOC species is equal
to that of toluene, 491,000 scf of air would be required.   Heating this air to
816° (1500°F) would require 13.87 million Btu.  If a credit of 25,000 Btu per
pound is allowed for the 12.2 pounds of VOC, heat requirements would be 13.56
million Btu.   If this heat were supplied by natural gas at a cost of $4 per
million Btu (N.  Houey,  Department of Energy, personal communication, Febru-
ary 23, 1983) and the incinerator were 100 percent efficient, the fuel cost
would be $55.35 per car (or $25.46 per car with the heat exchange option).  It
should be noted that according to AP-42,6 the combustion of the natural gas
required to control 12.2 pounds of VOC emissions would produce 2.37 pounds of
nitrogen oxide emissions.6  This would offset to some degree the reduction of
VOC emissions.  Incineration is estimated to have an overall efficiency (cap-
ture efficiency multiplied by the efficiency of the control device) of about
67.5 percent.

3.3  CARBON ADSORPTION
     The estimated cost of a carbon adsorber is about $36,000, and installa-
tion costs would run about 50 percent of the unit cost.  This makes the in-
stalled cost about $54,000.  Capital-related annual costs are as follows:
(1) capital recovery factor of 11.75 percent of the total  capital investment,
based upon a 20-year equipment life and a 10 percent interest rate; (2) pro-
perty taxes and insurance at 4 percent of total capital costs; and (3) oper-
ating and maintenance costs at 4.75 percent of total capital costs.  Steam
requirements would be 5 pounds per pound of VOC, and the cost would be $3.50
per thousand pounds.  Recovered VOC credits are estimated to be 10 cents per
pound.  The recovered VOC would be a hydrocarbon mixture,  and soma VOC would

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have to be recovered from a water solution; these considerations reduce VOC

recovery credits.

     The overall efficiency (capture efficiency multiplied by the efficiency

of the control device) probably would not exceed 67 percent.   The VOC-air

mixture entering the adsorber would have a maximum VOC content of 100 ppm.

The exit gas from a carbon adsorber in good working condition would typically

contain 10 to 25 ppm VOC.  If the air stream entering the adsorber were less

than 100 ppm VOC,  the recovery efficiency could be much less than 67 percent.

This treatment assumes that carbon adsorption is technically feasible, which

may not be the case.



3.4  COST-EFFECTIVENESS

     Table 1 shows capital and annual costs for incineration, incineration

with heat recovery, and carbon adsorption.  Costs range from $2,500 per ton of

VOC controlled with the carbon adsorption option to $18,600 per ton of VOC

controlled with incineration.  The basis for these estimates may be overly

optimistic.   None of these control methods is considered cost-effective.



         TABLE 1.   CAPITAL COSTS, ANNUAL COSTS, AND COST-EFFECTIVENESS
               FOR VOC CONTROL SYSTEMS (SEPTEMBER 1982 DOLLARS).



                                              Incineration with    Carbon
                                Incineration    heat recovery    adsorption

Capital Cost
 Installed equipment               90,000          180,000         54,000

Annual Cost
 Capital recovery factor           13,200           26,400          6,300
 Operating and maintenance          4,300            8,600          2,600
 Property taxes and insurance       3,600            7,200          2,200
 Steam and fuel                    57,200           26,300            200
 Total annual cost                 78,300           68,500         11,300
 VOC recovery credit                  0                0              800

Net Annual Cost                    78,300           68,500         10,500

Tons of VOC Controlled               4.2              4.2            4.2

Cost per Ton of VOC Controlled     18,600           16,300          2,500

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                            4.   REGULATORY ANALYSIS



     No draft regulation for the automobile refinishing industry is presented

hereii.

     The California Air Resources Board has classified regulating the automo-

bile refinishing industry as a low-priority item.   That agency maintains that

although statewide estimated emissions amount to 25,000 tons per year, en-

forcement would be nearly impossible because of the large number of small

sources that would have to be policed (T.  Preston, California Air Resources

Board,  personal communication,  February 2, 1983).   This same situation exists

in the Philadelphia AQCR.   Extensive development work is being done in the

areas of improved transfer efficiency and new product development.   It is

recommended that the Philadelphia AQCR continue to monitor'progress in these

areas,
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                                 REFERENCES
1.   Material Safety Data Sheets, E.  I.  duPont de Nemours and Company, Inc., F
    and F Department, Wilmington, Delaware:

    a.    White Lucite Acrylic Lacquer,  5338-L, November 23, 1981.
    b.    Blue Lucite M.  M.  Lacquer,  5366-L,  June 15, 1976.
    c.    White Centari Acrylic Enamel,  508-A, November 2, 1981.
    d.    Blue Centari Acrylic Enamel, 45370-A, May 6, 1982.
    Properties of duPont automobile paints.

2.   Booz, Allen, and Hamilton, Inc.   Surface Coating in the Automotive Refin-
    ishing Industry.  (Draft final report.)   Prepared for the U.S. Environ-
    mental Protection Agency, Research Triangle Park, North Carolina.  Decem-
    ber 30, 1977.

3.   PEDCo Environmental, Inc.  Volatile Organic Compound Emission Controls
    for the Wood Furniture Industry.   Arlington, Texas.   January 1983.

4.   Fitz and Fitz, Inc.   Sales brochure.   Auburn, Washington.

5.   U.S. Environmental Protection Agency.  Draft Document,  Control Technique
    Guidelines for the Control of Volatile Organic Emissions from Wood Furni-
    ture Coating.   Office of Air and Waste Management, Office of Air Quality
    Planning and Standards, Research Triangle Park, North Carolina.  April
    1979.

6.   U.S. Environmental Protection Agency.  Compilation of Air Pollutant
    Emission Factors.  Office of Air and Waste Management,  Office of Air
    Quality Planning and Standards,  Research Triangle Park, North Carolina.
    Third Edition.  AP-42, including Supplement 12 of April 1, 1981.
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