EPA-450/2-77-032 

December 1977 

(OAQPS NO. 1.2-086) 

GUIDELINE SERIES 

CONTROL OF VOLATILE 

ORGANIC EMISSIONS 

FROM EXISTING 

STATIONARY SOURCES 

VOLUME 111: SURFACE 

COATING OF METAL 

FURNITURE 

l J.S.ENVIRONMENTAL PROTECTION AGENCY 

Office of Air and Waste Management 

Office of Air Quality Planning and Standards 

Research Triangle Park, North Carolina 2771 1 
EPA-450/2-77-032 

(OAQPS NO. 1.2-086) 

CONTROL OF VOLATILE 

ORGANIC EMISSIONS FROM EXISTING 

STATIONARY SOURCES 


VOLUME 111: SURFACE COATING 

OF METAL FURNITURE 

Emissions Standards and Engineering Division 

Chemical and Petroleum Branch 

1.1;. ENL IRONMENTAI, PROTECTION AGENCY 

Office of Air and F'aste Management 

Office of Air Quality Planning and Standarcl~ 

Rerearch Triangle Park, North Carolina 2771 1 

Decem ber 1977 
tjAQPS GUIDELINE SERIES 

The guideline series of reports is being issued by the Office of Air Quality 

E'lanning and Stand~lrds (OAQPS) to provide information to state and local 

air pollution control agencies; for example, to provide guidance on the 

;icquisition and processing ol air qual~ty data and on the planning and 

analysis requisite for the maintenance of air quality. Reports published in 

this series will be available -- as supplies permit - from the Library Services 

Office (MD- 35) , U .S . Environmental Protection Agency, Research Triangle 

Park, North Carulina 27711; or, for a nominal fee, from the National 

Technical Information Servlce, 5285 Port Royal Road, Springfield, Virginia 

22161. 

Publication No. EPA-450/2-77-032 

(OAQPS No. 1.2-086) 
PREFACE 

This document is one of a series designed to inform Regional, State 

and local air pollution control agencies of techniques available for 

reducing emissions of volati 1 e organic compounds (VOC) from existing 

stationary sources. It deals with the surface coating of metal furniture. 

"Metal furniture" includes any furniture made of metal or any metal part 

which wi 11 be assembled with other metal , wood, fabric, plastic or glass 

p'arts to form a furniture piece. This document describes the industry, 

ildentifies sources and types of emissions, and appl icable methods and costs 

of reducing these emissions. It also discusses techniques for monitoring 

the organic solvent content of coatings for purposes of determining 

compliance with anticipated regulations. Detailed discussions on low 

organic sol vent coatings and add-on control technologies are found in 

"Control of Volatile Organic Emissions from Existing Stationary Sources - 

Volume I: Control Methods for Surface Coating operations. "l ASTM test 

methods for monitoring organic solvent technology are found in "Volume 11: 

Surface Coating of Cans, Coil, Paper, Fabric, Automobiles and Light Duty 

Trucks, 112 

The table below provides emission limitations that represent the 

presumptive norm which can be achieved through the application of reasonably 

avai labl e control technol ogy (RACT) . Reasonabl e avai 1 able control technol ogy 

is defined as the lowest emission limit that a particular source is capable 

of meeting by the application of control technology that is reasonably 

avai labl e considering technol ogical and economic feasi bi 1 i ty It may 

?!PA-450/2-76-028, November 1976, (OAQPS No. 1.2-067) 

2~~~-450/2-77-008, May 1977, (OAQPS No. 1.2-073) 
require technology that has been applied to similar, but not necessarily 

identical source categories. Since the definition of metal furniture 

includes a wide variety of products, it must be cautioned that the emission 

limits reported in this Preface are based on capabilities which are 

general to this industry, but may not be applicable to every facility. 

Affected Faci 1 it. .- Recommended Limitation 

kg of organic solvent I bs of organic sol vent 

emitted per liter of emitted per gallon of 

coating (minus water) coating (minus water) 

Metal Furni ture Coati ng 0.36 3 .O 

Line 

'This emission litnit is based on the use of low organic solvent coatings. 

It can also be achieved with water-borne coatings and is approximately 

13quivalent (on the basis of solids appl ied) to use of an add-on control 

dev ice which collects or destroys about 80 percent of the solvent from a 

conventional high organic solvent coating. Even greater reductions (up 

to 90 percent) can be achieved by installing new equipment which uses 

powder or electrodeposited water-borne coatings. It is believed that most 

metal furniture facil ities will seek to meet future regulations through 

the use of coatings which are low in organic solvent. 
GLOSSARY 

Prime coat means the first film of coating applied in a two-coat operation. 

* Topcoat means the final film of coating applied in a two-coat operation. 

* Single coat means only one film of coating is applied on the metal 

substrate. 

Faraday caging means a repelling force generated during electrostatic 

spraying of powders in corners and small enclosed areas of metal 

substrate, 

Blocking agent means an agent which is released from the polymer matrix 

during the curing process. It is normally an organic radical and spl its 

from the monomer or oligmer at a predetermined temperature, thereby 

exposing reactive sites which then combine to form the polymer. Such 

reactions during the curing process may release additional volatile 

organic compounds into the atmosphere. 

Low organic solvent coating refers to coatings which contain less organic 

solvent than the conventional coatings used by industry, Low organic solvent 

coatings include water-borne, higher-solids, electrodeposition and powder 

coatings, 
CONVERS ION FACTORS FOR METRIC UNITS 


Equival ent 

-Me,tric Unit Metric Name English Unit 

Kg kilogram (loJgrams) 2.2046 lb 

1iter 1 iter 0.0353 ft3 

dscm dry standard cubic meter 35.31 ft3 

scmm standard cubic meter per min. 35.31 ft3/min 

Mg 

metric ton 

6 megagram (10 grams) 

6 metric ton (10 grams) 

2,204.6 

2,204.6 

lb 

Ib 

In keeping wi th U .S. Environmental Protection Agency pol icy,metri c 

units are used in this report.. These units may be converted to common 

English units by using the above conversion factors. 

Temperature in degrees Celsius (CO) can be converted to temperature 

in degrees Farenheit (OF) by the following formula: 

to = temperature in degrees Farenheit 

to, = temperature in degrees Celsius or degrees Ccntigraae 
TABLE OF CONTENTS 

PREFACE ................................ iii 


GLOSSARY ............................... v 


CONVERSION FACTORS FOR METRIC UNITS .................. iv 


1.0 SOURCES AND TYPES OF EMISSIONS .................. 1-1 


1 General Discussion ...................... 1-1 


1.2 Processes and Emission Points ................ 1-3 


1.3 Reference!.. .......................... 1-10 


2..0 APPLICABLE SYSTEMS OF EMISSION REDUCTION ............. 2-1 


2.1 Powder Coating. . ., ..................... 2-2 


2.2 Electrodeposition ...................... 2-3 


2.3 Water-Borne Spray. Dip. or Flowcoat ............. 2-4 


2.5 Carbon Adsorption ...................... 2-6 


2.6 Incineration ......................... 2-8 


2.7 References .......................... 2-10 


3.0 COSTANALYSIS ........................... 3-1 


3.1 Introduction......................... 3-1 


3.1.1 Purpose. ....................... 3-1 


3.1.2 Scope ......................... 3-1 


3.1.3 Use of Model Plants .................. 3-2 


3.1.4 Bases for Capital Cost Estimates ........... 3-3 


3.1.5 Bases for Annual ized Cost Estimates .......... 3-3 


3.2 Control of Organic Solvent Emissions - Cost Estimates ....................... 3-4 


3.2.1 Electrostatic Spray Line ............... 3-6 


3.2.2 Dip Line ........................ 3-10 


3.3 Cost Effectiveness ...................... 3-11 


3.4 Summary ........................... 3-14 


3.5 References .......................... 3-16 

4.0 ADVERSE AND BENEFICIAL EFFECTS OF APPLYING 

TECHNOLOGY .......................... 4-1 


4.1 Powder Coatings ...................... 4-1 


4.2 Electrodeposition ..................... 4-2 


4.3 Water-Borne Coatings .................... 4-4 


4.4 Higher Solids Coatings ................... 4-5 


4.5 Carbon Adxorption ..................... 4-5 


4.6 1ncinerat:ion ........................ 4-6 


4.7 Reference.> ......................... 4-8 


5.0 MONITORING TECHNIQUES AND ENFORCEMENT ASPECTS .......... 5-1 


APPENDIX A .SAMPLE CALCULATIONS OF CONTROL OPTIONS ......... A-1 


References. .......................... A-5 


viii 
i.O SOURCES AND TYPES OF EMISSIONS 

This chapter provides a general introduction to the metal furniture 

industry, the methoas by which conventional solvent-borne coatings are 

applied, and volati 7e organic solvent (VOC) emissions which can be 

expected from these coatings. 

1.1 GENERAL DISCUSSION 

Metal furniture is manufactured for both indoor and outdoor use, and 

may be divided into two general categories; "business and institutional " , and 

"household! Business and institutional furniture is manufactured for use 

in huspital s, schools, athletic stadiums, restaurants, laboratories and othel 

types of institutions, and government and private offices. Household 

metal furniture is manufactured mostly for home and general office use. 

A1 though there are more than twice as many manufacturers of metal household 

furniture, on the average, those that manufacture metal business and 

institutional furniture are twice as large. About half of the metal household furniture manuf~cturers employ less than 20 employees.' Metal furniture 

includes a variety of items including tables, chairs, waste baskets, beds, 

desks, lockers, benches, she1 ving, file cabinets, lamps, room dividers and 

many other simil ar products. 

Metal furniture plants are 1 ocated throughout the United States, however, 

Illinois, California, Michigan, New York and Pennsylvania contain over 50 

percent of the plants in the industry. The Environmental Protection Agency's 

Region V contains about 30 percent of the industry, Regions I1 and IV about 

16 percent each, and Regions II1 and IX about 11 percent each. Plants vary 
in size depending on the type of furniture manufactured, the number of 

manufacturing and coating 1 ines, and the amount of assembly required. 

The manufacturinq markets of metal furniture facilities vary. Some 

plants manufacture metal furniture to be sold directly to consumers 

through retail stores. In contrast, "job shops", produce furniture on 

contract. The latter facilities apply coatings on many different furniture 

pieces according to the customer's specifications. The size of a metal 

furniture coating line varies depending on the furniture coated, the type 

01' coating application used, and on how many coats are applied. The 

coating 1 ine can have a steady production rate ranging from 8 to 24 feet 

per minute, or the furniture pieces may be coated sporadically. 

Coatings appl ied in each plant vary with personal preference, type of 

furniture, appl icat ion technique, pretreatment, and end use. Conventional 

coatings are applied at 0.7 to 1.5 mils thickness. Most of the coatings 

are enamels although some lacquers are also used. Some metal furniture 

pieces are coated with metal 1 ic coatings. The most comnon coatings are 

alkyds, epoxies and acrylics containing various mixtures of ketones, 

aromatic, a1 iphatic, terpene, ester, ether and alcohol solvents. The coatings 

are often purchased at higher sol ids contents but are thinned for application 

to about 25 to 35 volume percent sol.ids. 

The coatings applied to metal furniture must protect the metal from 

corrosion, be it indoor or outdoor furniture. They must have good adhesion 

properties to avoid peeling or chipping, must be durable and must meet 

customer standards of appearance. 
1.2 PROCESSES AND EMISSION POINTS 

Figure 1-1 depicts a typical metal furniture line. Unassembled, 

stmi-assembl ed or totally assembled furniture pieces first are transported 

on a conveyor throuqh a cleansing process. Here an alkaline cleaner 

rmoves mill scale, grease and oil. After a hot rinse, iron phosphate or 

other pretreatment often is employed to improve coating adhesion and prevent 

rusting. Following a cold rlnse, thc pieces are dried at 130"-180°C 

(;!50° - 350" F) . In some cases, the entire wash section is omitted and the 

pieces are c 1 eaned in a shot--blasting chamber or organic sol vent cleaning 

operati on. 

Most me tal furniture is finished with a single-coat operation. Some 

pieces, however, require a prime coat appl ication due to the topcoat 

formulation or the end-use of the piece. The prime coat may be applied by 

electrostatic or conventionall spray, dip or flowcoating techniques. The 

substrate with the prime coat then goes through a flashoff peri od to avoid 

popping of the f ilrn when the coating is baked. The prime coat is usually 

bdked in an oven at about 160" to 200°C (300"-400°F). 

The topcoat or d single coat may be appl ied by spraying, dipping or 

flowcoating. Ifa ~lantmanufactures furniture in a variety of colors, 

necessitating frequent color changes, the coating is usually sprayed either 

electrostatically or by conventional airless or air spray methods. If a 

plant manufactures furniture in only one or two colors, the coating often 

is applied either by flowcoating or bj dipping. 

Electrostatic spray coating may be performed either manually or automati cal ly a1 though no st spray coating in metal furniture facil ities is done 

manually. The paint particles are negatively charged, move along the path 

of' an electric force field created between the spray gun and the grounded 

metal furniture piece, and coat the piece. This method of application is 

more efficient than the conventional ai r or air1 ess spray methods because 

there is less overspray thereby reducing the amount of paint that must be 

sprayed and the VOC that evaporates. 

Spray coating is performed in a booth to contain overspray and prevent 

surface contamination, Two kinds of spray booths are usually found in 

the metal furniture industry, down draft or side draft. Air flow rates 

fnm spray booths vary depending on whether it is occupied by people, on type 

of spray booth, and on size of spray booth and openings. The minimum air 

ve'locities are prescribed by OSHA to assure capture of paint 

particles and insure the VOC concentration does not exceed the threshold 

limit values. 

Dip coating is the immersion of pieces into a coating bath. After 

withdrawal, the excess coating is allowed to drain back into the tank. 

Flowcoating involves conveying the piece over an enclosed sink, and 

allowing pumped streams of coating to hit the piece from all angles, flow 

over the piece and coat it. Excess coating drains back into the sink, is 

filtered and pumped hack into a coating hol ding tank. 

The coated furniture is usually baked in an oven but in some cases is 

air dried. The flashoff area 1ies between the coating application area 

and the oven. This allows solvents to rise slowly in the coating film, 

thus avoiding popping of the film when the coating is baked. The fraction 

of the solvent which evaporates in this area will depend on the type 

of coating used, line speed and the distance between the application area 

and oven. 
The baking oven may contain several zones at temperature ranges of 

160" to 230°C (300-450°F). The exhaust air flow rate from the ovens will 

depend on the type and size of the oven, and the size of the oven openings 

through which the parts enter and exit. Fire Underwriters Insurance 

typically requires that the atmosphere within industrial baking ovens 

not exceed 25 percent of the lower explosive limit (LEL) of the evaporating 

solvents. This means that about 10,000 scf o f a i r is required to evaporate 

1 gallon of solvent. Some facilities have been allowed to operate at higher 

LEL 's (around 50 percent), however, if proper LEL monitoring equipment is 

used. Many metal furniture baking ovens presently operate between 5-1 5 

percent of the LEL. The principle reason for maintaining such low concentration levels is that the oven must be maintained under negative pressure to 

avoid spillage of fumes into the plant. This requires a 15 mpm (50 fpm) 

to a 45 fpm (1 50 fpm) air velocity through the oven openings. The lower 

velocities are common to ovens which use air curtains to contain spillage. 

Siince the openings are often large to accommodate the variety of coated metal 

furniture pieces, the air flow required to maintain the oven under negative pressllre may exceed the air flow required to maintain the oven below 25 percent LEL. 

Volatile organic compounds are emitted from the coating area, the flashoff area and the oven. It is estimated that in spray applications, about I

65-80 percent of the VOC are released from the spray booth and the flashoff , 

1 

area, and the remaining 20-35 percent from the oven. For a dip or flowcoat i 

application, it is estimated that about 50-60 percent of the VOC are emitted 

from the coating and flashoff area, and the other 40-50 percent from the oven. 
Table 1-1 summarizes estimated VOC emissions from metal furniture coating 

operations. Note that emissions will vary from l i n e t o line due to its 

construction and the type of coating applied. 

Figure 1-2 displays the relationship between VOC emissions and flowr13te with isopleths of organic concentrations (LEL). Note that for a given 

emission rate, the exhaust flowrate at one percent LEL concentration is 

110times that at 10 percent LEL. The flowrate and resulting concentrations 

are a function of many factors; open or enclosed spray booths, dip or 

flowcoater, flashoff area or an oven. Unfortunately, flowrates are often 

designed for the worst situation and may be excessive for the typical 

piece coated by the facility. 
-- -- 

Tab1 e 1-1 DISTRIBUTION OF VOC EMISSIONSaFROM METAL FURNITURE 

COATING LINES 

Appl icat ion Application and 

Met hod Fl ashoff Area Oven 

Electrostatic Spray 

Conventional Air or 

Airless Spray 

Dip 

Flow 

a The base case coating is applied at 25 volume percent solids, 75 volume percent organic solvent 

which is equivalent to a VOC emission factor of 0.66 kg of organic solvent per liter of coating 

(5.5 lbslgal) minus water. 
20 40 60 80 100 120 140 160 180 200 

lbs of organic solvent (VOC) emitted per hour 

Figure 1-2. Re1 ati onshi p between VOC emission, exhaust f lowrates and 

VOC concentrati ons. 
1.3 REFERENCES 

1. Sherman, Michael, S., Director of Economic and Market Research, 

Summer and Casual Furniture Manufacturers Association, 1 etter to 

V. Gallagher in comment to draft of this document. Letters dated 

August 5, 1977 and August 12, 1977. 
- -- -- -- 

2.0 APPLICABLE SYSTEMS OF EMISSION REDUCTION 

This chapter discusses low polluting coatings and add-on equipment 

for the control of VOC from conventional coating applications used in the 

metal furniture industry. It a1 so discusses other methods of applying 

coatings (powder and el ectrodeposi tion) which result in low VOC emissions. 

Tab1 e 2 SUMMARY OF APPLICABLE CONTROL TECHNOLOGY 

FOR METAL FURNITURE 

Percent Reduction In 

Control Techno1 ogy Coating Appl i cation Organic Emi ssi ons 

-

Powder (spray or dip) Top or single coat 95-9ga 

Water-borne (el ectro- Prime or single coat 

deposition) 

Water-borne (spray, di p Prime, top or single coat 60-9oa 

or fl wcoat) 

High!er sol i ds (spray) Top or single coat 50-8oa 

Carbon adsorption Prime, top or single 

coat ( appl i cation 

and flashoff areas) 

Incineration Prime, top or single coat gob 

(ovens) 

a~hebase case against which these percent reductions were calculated is a 

high organic solvent coating which contains 25 volume percent solids and 75 

volume percent organic solvents. The transfer efficiencies for liquid coatings were assumed to be about 80 percent for spray and 5)U percent for dip or flowcoat, for powders about 93 percent, and for electrodeposition 99 percent. 

b~his percent reduction in VOC emissions is only across the control device, and 

does not take into account the capture efficiency. 
2.1 POWDER COATING 

Powder coatings nilay be applied electrostatically by spraying or dipping, 

or by dipping the preheated metal into a fluidized bed. Electrostatic 

spraying of powder is used more widely in metal furniture than fluidize bed 

because of its abi! ity to coat the pieces with thinner films of coating 

Elec.trostatic sprayed powders can be applied at film thicknesses of 2 m 1 s 

or greater while f1:~iclised bed powders are limited to 6 mils or greater 

After application, the powder particles are melted and cured in the oven to 

form a continuous ,sol id film. Although powders appear to be 100 percent 

solids, it is not unusual for them to contain small quantities of entrapped 

organic solvent. Powders can release up to 10 weight percent of VOC during 

the curing process. ' Therefore, the reduction in emissions for powders may 

range from 95 to 99 percent over conventional systems. Powder coatings are 

presently being applied on some furniture such as outdoor and indoor furniture, 

bed and chair frames, shelving and stadium seating. 2,3,4 

Electrostatic powder spray coating may be performed either manually or 

automatically. Powder particles are charged as they pass through the spray 

gun, and subsequently are attracted to the grounded metal furniture piece. 

The powder can wrap around the edges of conipl icated forms and is self-leveling 

on flat pieces. Film thickness may be controlled by voltaqe,and a thickness of 

3 to 4 mils can easily be achieved. Film thicknesses of 2 to 3 mils can be 

achl~eved with special attention and a very close control. Thinner films, however, 

have been achieved only in the laboratories and not on production 1 ines. 5 

Powder spray roating requires a booth as does spray coating with 

conventional coati nqs . However, ventilation requi rements are greatly reduced 

from those of solventborne spray booths mainly because the booths are not 

occupied. This obviates the need to heat or air condition air going into the 
spray booth and saves energy. Most powder overspray may be reclaimed and 

reused. Some overspray, however, has to be removed and reprocessed because 

it consists of larger and heavier granules which are not suitable for reuse. 6 

The ability to collelzt overspray can provide a high coating util ization. To 

change colors in a powder coating system, the booth and recovery units must 

be cleaned thorough1.y to avoid color contamination. To shorten the time 

required for a color changeover, some plants have several recovery units that 

may be easily connec%ed to the spray booth. Some have also purchased multiple 

mobi 1 e spray booths with associated recovery equipment. 

Powder coating may also he appl ied by dipping metal pieces into a fluidized 

bed. In the metal furniture industry, dipping has the disadvantage of applying powder only in thick films (at least 6 mils). The metal furniture piece 

is preheated to the melting point of the powder, dipped into the bed and 

held there until the desired film thickness is achieved. In electrostatic 

fluid bed coating, the powder particles are charged and become attracted to 

the grounded ,usual ly unheated ,metal piece moving through the bed. The 1 atter 

method is 1 imi ted to simp1 e shapes. 

Powder coatinqs are baked at temperatures of 180" to 230°C (300-450°F). 

Since the concentrations of organics are almost insignificant compared to 

conventi onal coat ings and no flashoff zones are requi red, smaller ovens may be 

installed. Further technical details on the use of powder coating's may be 

7 found in Vulume I, Sections 3.3.3 and 3.3.5. 

2.2 ELECTRODEPOSITION 

Electrodeposition (EDP) is being used at several facilities to coat metal 

furniture with 0.5 to 1.2 mils of film thickness. 8,9910 The thickness may 

be adjusted somewhat by varying voltage and immersion time. Electrodeposi tion 
11 

provides increased corrosion protection and applies thin coatings more 

uniformly and at a greater transfer efficiency than any other application 

system. A1 though electrodeposi tion was previously 1imi ted to one to two 

colors, a new installati on will be applying four different colors. 

EDP coat-ings are applied from an aqueous bath which contains about 

10--15 volume percent sol ids and 2-4 volume percent organic solvents. A 

direct current is applied in the bath causing the solids to become attached 

to the grounded metal piece. Electrodeposition can be performed either 

anodically or cathod~cally. The metal emerges from the bath with a coating 

containing about 90 vol ume percent solids, 1 to 2 percent organic solvent and 

the balance water. 1t is rinsed to eliminate excess paint particles and 

bak.ed at 160' to 180°C (300-350°F). The rinsing water is often obtained from 

the discharge from the ultrafilter. Ultrafiltration purges most of the 

soluble organics, amines and contaminating ions from the rinse residue and 

returns the solids portion to the bath. 

For further technical details in the use of electrodeposition coating 

12 technology, see Volume, Section 3.3.1. 

2.3 WATER-WRNE - SPRAY, DIP OR FLOWCOAT 

Since water-borne coatings have similar characteristics to organic 

sol vent-borne coatings, they can often be substituted for existing sol ventborne coatings without requiring major changes to existing coating equipment. 

There may be however, sane necessary alterations in equipment or the coating 

1 in12 to protect the equipment from corrosion,to lengthen the flashoff area 

and sometimes to control the humidity in the application and flashoff areas. 

Several metal coating facil ities have been successful in converting their 

existing flow, dip and spray (both electrostatic and conventional ) operation 

to apply water-borne coatings. 
Some organic solvents must be a part of a water-borne coating to 

temper the evaporation rate,and to provide film coalescence and the necessary 

film properties. A reduction of 60-90 percent in VOC emissions may be 

obt,ained by conversion to a water-borne coating. 

Water-borne coatings may be sprayed electrostatical ly on small coating 

1 ines if the entire coating system is electrically isolated. On larger lines, 

however, where the paint storage areas are hundreds or even thousands of 

feet away from the appl ication areas, electric isolation of the entire 

system becomes difficult and sometimes financially impractical. 13314 co1 or 

changes often require on1 y that the app'l ication system be flushed out with 

water. Coating with water-borne coatings may require more attenti on to the 

coating process since temperature, humidity, gun-to-metal distance and 

flashoff time may change the looks and performance of the coating. Convent ional 

air and airless spray techniques may also be used to apply water-borne coat ings. 

Fur1:her technical details on the use of water-borne coatings may be found in 

Volume I,Sections 3.3.1 and 3.3.5. 15 

2.4 HIGHER SOLIDS SPPAY 

The achievable VOC emission reduction by switching to higher solids 

coatings may range from 50 to 80 percent depending on the type of coating 

used previously and the volume percentage of solids. Higher sol ids coatings 

16

are being used on both pilot and full production 1 ines. 

Higher solids coatings can be applied most efficiently by automated 

electrostatic spraying a1 though manual and conventional spraying techniques 

can a1 so be used. Some minimal increase in energy may be required to raise 

the pressure of the spray gun, heat the coating, or power electrostatic spray 
17 

equipment in order to pump and atomize these coatings due to their higher 

viscosities. Transfer efficiencies of higher sol ids coatings are often 

better than those of conventional coatings, particularly when sprayed 

el ectrostatical ly . 

18 

As the solids content is increased in a coating, less solvent is 

released for each dry mil of coating. This may permit some reduction in 

air flow to the booth (if the air flow was originaiiy determined by the threshold 

limit of organic sol vents) resulting in an energy savings.19 This reduction 

however, will be 1 imited by the successful collection of overspray particles. The 

lower solvent content may also allow the air flow from the oven to be reduced. 

Further technical details on the use of high solids coatings may be 

20 found in Volume I,Section 3.3.2. 

2.5 CARBON ADSORPT ION 

As discussed in Chapter 1, from 50 to 80 percent of the volatile organic 

compounds from metal furniture coatings are emi tted from the application 

and flashoff areas. The use of carbon adsorption can reduce emissions from these 

areas by 75 to 90 percent depending on the capture efficiency into the control 

devi ce . 

Carbon adsorption is considered a viable control option for the 

application and flashoff areas because exhaust gases are at ambient temperature 

and contain only small amounts of particulate matter that could contaminate 

the carbon bed. Althouqh there are no known installations of a carbon 

2 1 adsorption system in a metal furniture plant, it is technically feasible, 

and no new invention would be required. Pilot studies will be necessary, 

however. 
The size of a carbon adsorption unit is dependent on the exhaust flow 

rate, its desorption period and VQC concentration. The flow rates and 

vol~atile organic concentrations will vary from each facility because of 

the wide variety of metal furniture manufactured. If any reduction in 

the flow rate of the exhaust air (within compliance with safety regulations) 

can be achieved, a smaller and less expensive carbon adsorber can be used. 

This reduces both capital and fixed operating costs. In order to optimize 

application of an add-on control device, the flashoff areas must be enclosed 

to minimize intrusion of air. 

In conventional spray booths, some particulate matter from overspray is 

captured by dry filters, or water or oil wash curtains at about 95 pcircent 

efficiency. 22 Additional particulate removal, however, may be necessary to 

prevent contamination of the carbon bed. Although there is little possibility 

that the recovered solvents may be directly recycled (because of the complex 

solvent mixtures), they may be valuable (3s supplementary fuel for boilers or 

heaters. 

Carbon adsorption systems can be large and require a large amount of 

floor space. Some 1 arge metal furniture faci 1 ities may require several dual -bed 

carbon adsorption units in parallel operation. Availability of the requisite 

space is an important consideration. The metal furniture operator may have 

to construct an addition to the plant. 

Further technical details on the use of carbon adsorption may be found 

in Volume I, Section 3.2.1. 23 
2.6 INCINERATION 

There are no serious technical problems associated with the use of 

either catalytic or noncatalytic incinerators on metal furniture facilities. 

Incineration has been used to reduce VOC emissions from ovens in metal 

24 furniture faci 1 ities. 

Incinerators are more efficient than carbon adsorbers for reducing VOC 

emissions from metal furniture ovens. Althouqh some energy is. required to brinq 

the oven exhaust to incineration temperature, this incremental energy can 

ble minimized by the use of primary heat exchangers. The concentration of organic 

vapors is usually higher in the oven exhaust (5-15 percent of LEL) than in 

the application and flashoff areas and provides some fuel for the incinerator. 

Particulate and condensible matter that is often found in the exhaust from 

higher temperature baking ovens will not affect an incinerator, whereas, it 

will coat a carbon bed and render it ineffective. Incineration can also be 

u!jed to reduce VOC -from application and flashoff areas. It will normally 

be necessary (but not always possible) for the operator to incorporate heat 

recovery systems to reduce fuel consumption to an acceptable level. Otherwise 

incineration of ambient temperature, low VOC concentration, gas streams is 

often energy intensive. 

If the exhaust rate can be lowered, within the 1 imits of health and 

fire safety regulations, less fuel will be required in the incinerator. A 

higher VOC concentration will provide a greater fraction of the total fuel 

requirement. Thus, increasing the VOC level not only reduces the size of 

the required incinerator and its capita1 and fixed operating cost, but also 

the fuel requi rements. The degree of difficiil ty in retrofitting incinerators 
to (existing metal furniture facilities will vary depending on the age of the 

equipment and facil ity, and where the equipment is located. 

In the past, most incinerators were fired with natural gas. Due to 

the energy shortages, some incinerators have been converted to No. 2 fuel 

oil, and more energy recovery rnethods have been used to reduce energy 

consumption. 

Further technical details on the use of incineration may be found in 

Volume I, Section 3.2.2. 26 
REFERENCES 

LeBras, Louis R., Technical Division Director, PPG Industries, Pittsburgh, 

Pa. Letter to Vera Gallagher in comment to draft of this document. 

Letter dated Septeher 22, 1977. 

Springborn Laboratories, Inc., (formerly DeBell & Richardson, Inc. ) 

Trip Report Nos. 57,72,85,86,100,108, General Surface Coating Study 

Contract by EPA 68-02-2075. 

"Powder System Cuts Finishing Costs at Westinghouse" and "Powder Coating 

Seating Scores at Iowa State's New Statiurn": Powder Finishing World. 

Pages 20-22 and 50-52. Second quarter, 1975. 

Bessel sen, John, Painting With Powder. Technical Paper presented at the 

Associ ati on for Finishing Processes of Society of Manufacturing Engineers 

in Cincinnati, Ohio, 1975. (FC 76-431). 

LeBras, Op. Cit. 

Dornbos, David L. Sr., Steel case Incorporated, Grand Rapids, Michigan. 

Letter to Vera Gallagher in comment of this document. Letter dated 

August 31, 1977. 

OAQPS Guide1 ines "Control of Volatile Organic Emissions From histing 

Stationary Sources-Volume I"Control Methods for Surface Coating Operations", 

EPA - 450/2-76-028; November 1976. 

Springborn Laboratories, Trip Report No. 103. General Surface Coating Study, 

Contract by EPA 68-02-2075. 

Schrantz, Joe, Twin Electrostatic Tanks Add Versatility at Star Industries. 

Industrial Finishing, pages 20-26. January 1976. 

Two Electrocoatiny Tanks Boost Production at Waterloo Industries, Industrial 

Finishing, pages 34-36. June 1975. 

LeBras, Op. Cit. 

Volume I,Op. Cit. 

Dornbos, Op. C-it. 

Zimnt, Werner S., Research Fellow, E.T. DuPont de Nemours & Company. 

Letter to Vera Gallagher in comment to draft of this document. Letter 

dated August 25, 1977. 

Volume I,Op. Cit. 

Springborn Laboratories Trip Report No. 41. General Surface Coating Study 

under Contract by EPA 68-02-2075. 
DeVittorio, 3. M., Appl ication Equipment for High-Sol ids and Plural 

Component Coatings. High-Sol ids Coatings, Volume I, No. 2, April 1976. 

LeBras, Op. Cit 

Lunde, Dona1d I,,Aqueous and High-Sol ids Acrylic Industrial Coatings. 

High-Solids Coatings, Volume I,No. 2, April 1976. 

Volume I,Op. Cit. 

Johnson, W.R., General Motors Corporation, Warren, Michigan. Letter 

to Radian Corporation commenting on "Evaluation of a Carbon Adsorption 

Incineration Control System for Autcl Assembly Plants." EPA Contract 

No. 68-02-1319, Task No. 46, January 1976. Dated March 12, 1976. 

Johnson, W. R. , General Motors Corporati on, Warren, Michigan. Letter 

to James A. McCarthy dated August 13, 1976. 

Volume I,Op. Cit. 

Springborn Laboratories, Inc. Trip Report No. 57, General Surface 

Coating Study Contract by EPA 68-02-2075. 

Volume I, Op. Cit. 
3.0 COST ANALYSIS 


3.1 INTRODUCTION 

3.1.1 Purpose 

The purpose of this chapter is to present estimated costs for controlling solvent emissions from existing coating lines at metal furniture plants. 

3.1.2 Scope 

Estimates of capital and annualized costs are presented for control 

1 ing VOC (Volatile Organic Compounds) from application areas and curing 

ovens associated with electrostatic spray and dip coating lines applying 

a single coat to metal shelves. The control alternatives considered 

applicable to a coating line using the conventional solvent thinned 

coating and for which cost estimates are developed include: 

Alternative I -Process Modification 

Conversion to a coating system applying one of the following 

low sol vent coating materials: 

1. Higher solids (70% or above) 

2. Waterborne 

3. Powder 

A1 ternative I I-dxhaust Gas Treatment 

Instal lation of hydrocarbon control equipment: 

1 . Carbon adsorption for appl ication exhausts 

2. Thermal incineration for oven exhausts 
Detailed control costs estimates are developed for existing coating 

2 2 lines with annual production rates of 278,000 m jyr. and 4,000,000 m /yr. 

2 2 for electrostatic spraying and 650,000 m /.yr. and 2,100,000 m lyr. for 

dip coating. The cost effectiveness (annual ized cost (credit) per metric 

unit weight of VOC controlled) for the a1 ternative control measures 

considered are estimated and graphically displayed for the range- of production rates analyzed . 

3.1.3 Use of Model Plants 

The cost analysis provided in this chapter relies upon the use 

of model coating 1 ines that are basically defined by an annual product 

coverage rate (square meterslyear) for 1920 hours operation. In general , 

no attempt has been made to consider detailed design characteristics 

for the model lines in terms of process equipment requirements, line 

speed, etc. However, it was necessary to estimate the number of spray 

booths, required coating thickness, transfer efficiencies, oven and 

booth exhaust rates in order to estimate capital and operating costs for 

the control a1 ternati ves considered. 

It is emphasized that model coating lines used in this analysis are 

particularly simple in that a one color single coat is applied to metal 

shelves. Analyzinq multi-color coating systems is beyond the scope of 

this analysis although some general cost implications will be summarized 

later. Other factors influencing cost analyses of coating lines different than the models chosen will be covered in the discussion of the 

bases for model 1 ine cost estimates. Finally, although control cost 
estimates based upon the model plant approach may differ with actual 

costs incurred, they are considered to be t.he best means of compari,ng 

the relative costs and cost-effectiveness of alternative control measures. 

3.1.4 Bases for Capital ------ Cost Estimates 

Capital cost estimates are intended to represent the total capital 

required to purchase and install necessary control or process equipment. 

For coating lines conv82rting to low solvent coatings, capital costs 

for control are generally incremental investments required to apply the 

difflerent coatings. It has been assumed throughout the model cost analysis 

that existing pre-treatment and curing equipment will not require modification in going to low-solvent coatings. This should not be interpreted 

to mean that such modifica.tions are unnecessary i n a l l cases. Rather, 

factors such as finish specifications and the condition of existing equipment will dictate how capital investments for actual lines will compare 

with the model estimates. The cost estimates provided were developed 

from EPA contractor studies and by contacting facilities that have implemented coating 1 ine conversions. 7'9'10 A11 capital costs are intended 

to r e f 1 e c t second quarter 1977 do1 lars. 

3.1 .5 Bases for --. Annual ized Cost Estimates. 

Annualized cost estimates for the control alternatives considered 

are developed to reflect annual charges for capital required to purchase 

and instal 1 process equipment or control systems, operating and maintenance 

costs and miscellaneous recurring costs such as taxes, insurance and administrative overhead. Capital charges are calculated using the "capital 
recovery factor" formula. Operating costs include costs for materials, 

utilities, labor and waste disposal. Net annualized costs for process 

changes, i.e. 1 ine conversions, are the incremental costs in going from 

the conventional solvent coating to the I~JWsolvent coatlng. As evidenced 

later in this chapter*, some conversions are projected to result in net 

annualized savings wbile others appear to result in increased annual costs. 

The bases for these ~1rojec.ted incremental costs or savings were provided 

in References 1 and 2. Again it is emphasized that these model coating 

line analyses are provided as a means of comparing the relative costs of 

a1 ternative control measures. The area of estimati ng incremental annual 

costs (savinqs) for alternative coatings is one in which all coating 

sup~pliers have devoted considerable resources. Unsurprisingly, varying 

some key assumptions can alter the conclusions drastically. Annual 

coating material costs appear to have the greatest impact on annual costs 

(savings) when comparing different coatings. Differences in coating 

thickness requirements, transfer efficiencies, raw material costs and sol ids 

content all influence this cost element. Assumptions used in this analysis 

are provided later in Table 3-2 which lists technical assumptions associated 

with the model coating lines. General cost factors used to estimate annualized costs for the model coatinq lines are provided in Table 3-1. All 

annual ized cost estimates are current. 

3.2 CONTROL OF SOLVFNT EMISSIONS FROM METAL FURNITURE SURFACE COATING 

- COST ESTIMATES 

The technical parameters used in developing the control cost estimates 
Table 3-1. COST FACTORS USED IN COMPUTING ANNUALIZED COSTS 

I. Direct Operating Costs 

A. Materials (As purchased) : 

* - A1 kyd conventional so lvent coating (40% solids) $2.00/1 iter ($8/gal) 

* - Polyester high solids coating (70% solids) $3.70/1 iter ($14/gal) 

* - Alkyd Waterborne coat ing (402 sol ids) $2.40/1 iter ($9/gal) 

- Epoxy powder coating $3.30/kg ($1.5O/l b) 

* - Electrodeposi tion waterborne (60% sol ids) $2.90/1 iter ($1 1 /gal ) 

- Carbon $2.20/kg ($1.00/lb) 

2. Utilities 

- Electricity 

- Natural gas $l.gO/thousand joules 

($2.00/million Btu) - Steam $5.50/thousand Kg 

($2.50/thousand I b) 

- Boiler feed water $0.13/thousand liters 

($0.50/thousand gal ) 

3. Direct Labor 

4. Maintenance Labor 

- Process modi ficati ons $1 O/man- hour 

- Add-on systems 0.02 x Capital Cost 

5. Maintenance Materials 0.02 x Capital Cost 

6. Waste Disposal 

- El ectrodeposi tion $0.008/1 iter coating ($0.03/gal) 

- All others $O.O3/l iter coating ($O.ll/gal) 

Annual ized Capital Charges 

1. Depreciation and interest 0.1468 x Capital Cost 

2. Taxes, insurance, administrative charges 0.04 x Captial Cost 

* By volume 
provided in Tables 3-3 and 3-4 are summarized in Table 3-2. Additional 

information regarding the expected range for many of these parameters is 

included in Chapters Two and Three of this document. 

3.2.1 Electrostatic Spray Line 

Capital and annual i zed costs for control a1 ternatives appl icabl e to 

electrostatic spray coating lines are presented in Table 3-3. Capital costs 

for converting lines to higher solids coatings (70% and above) or to waterborne 

coatings are related to appl ication equipment modifications only. Sources 

estimated conversion costs at between $1 0,000-$15,000 per automatic station 

and about $1,000 for manual booths. 3'10 The above estimates change radically 

for waterborne if paint sources are not located close to application equipment 

and if stainless steel piping is required for paint recirculation systems. 

Additionally, as mentioned in Chapter Three, attempting to insulate the remote 

paint source configurat~on from ground to comply with OSHA requirements creates 

technical problems. Capital costs for converting to a powder coating are 

associated with instal ldtion at powder application and recovery systems. Since 

models considered are one color 1 ines, only one recovery system is included 

in capital cost estimates. Mu1 ti-color 1 ines with production rates comparable 

to modlel lines may realize higher costs for additional recovery systems in 

order to minimize the longer times associated with powder color changes. 

Capital costs for achieving VOC emission reductions comparable to low solvent 

coatings (i.e., 80% and greater) using exhaust gas treatment appear to be 

greater than line conversion costs. 
Tab1 e 3-2. TECHNICAL PARAMETERS FOR MODEL COATING LINES 

Electrostatic Spray Li tie 

Number of Booths 

Automatic 

Manual 

Dry Coating Thickness, ~m (mils) 

Conventional sol ver t 

Hligher sol ids 

Waterborne 

Powder 

Tranisfer efficiencies 

Exhaust gas volumes , N m 3Isec (scfm) 

Dip Line 

Dry Colating Thickness, 11m (mi 1 s) 

Conventional sol vent 

klaterborne 

Electrodeposition 

Transfer Efficiencies Same as Table 2 - Chapter 2 

Exhaust gas volumes, -~m"/sec. (scfm) 

Clip Tank 
Table 1-3. CONTROL COSTS FOR M(DEt EXISTING ELECTROSTATIC SPRAY COATING LINES 

Alternative I - Process Change: 

Installed ~aoital Cost !$000) 

Direct Oper ting Costs (savings) 

( WoO/yr) P 

Capital Charges ($000/yr.) 

278,000 Square ~eters/~ear' 

(3,000,000 Square Feet/Year) 

Baseline Costs Incremental Co_s_t~fp_r- Conversion 

Higher 

25% solids Solids Waterborne Powder 

255b / 15' I lid 1 6oe 

I I I 

1 

I 

4,000,000 Square ~eters/~ear~ 

(48,000,000 Square Feet/Year) 

Baseline Costs Incren~ental Costs for Convet* 

25% solids ! !~~~~~ 1 ~ate~r-irne 1 ~;zr 

1,200~ 

1 I 

i I 

! 

Net Annualized Cost (credit) ($000/yr) 

Solvent Emissions Controlled ( ~ ~ j ~ r j ~ 

percent Emissior Reduction 

Cost(cred1t) per Mg of VOC 

rentrollpd ($/Mu) 

---- A -" -- Alternative I1 - Exhaust Gas Jredtment (Oven) (Spray Bootb) 

Thermal Incinerator parban Adsorpt~on Oven 

I (Spray Booth) 1 Ol:"~inerator Carbon Adsorption 1 

with Primary I Solvent at with Primarv Solvent at 1 and 

-- Heat Recovery _ -+Fuel Valve I Booth I Heat Recovery Fuel Value j Booth. 

i I I I 

h Installed Capital Cost ($000) 

Direct Operating Costs ($000/~r) 

Capital Charges ($iIOO/yr) 

Net Annualized Lost ($00O/yrj 

Solvent Emissions Control led (Mglyr) 

Percent Emission Reduction (Total ) 

Cost per Mg of VOC controlled ($/Mg) 

a~necolor system operating 1920 hourslyear and coating metal shelves - single coat. 

'~xcludes metal pre-treatment equipment and dry-off oven costs for line (reference 1,2) 

CApplication and paint circulating equipment modifications (references 3, 10). 

d~etter insulation from ground to prevent electrical shock and corrosion protection (references 3,4) 

eBooths and recovery system (reference 6). 

f~eferences 1,2. 

g~g = megagram = 1 metric ton

h~eferences 1 , 2. 
I 

Table 3-4. CONTROL COSTS FOR MODEL EXISTING DIP COATING LINES 

,000 Square ~eters/Year" 2,100,000 Square f4eters/yeara 

10,000 Square Meters/Year) (22,500,000 Square Feet/Year) 

I 3asel ine Costs Incrmental Costs for conversion1 Baseline Costs 1 Incremental Costs for Conversion Alternative I- Process Chanqe: 

25% Solids - Waterborne --.- EDP 25% Solids Waterborne ., EDP 

installed Capital Cost ($000) l0Sb 3C 1 24d 21 5b 5C 208~ 

Direct Operating Costs (Savings) 

($000/yr) 

Capital Charges ($OOO/yr) 

Net Annualized Cost (credit) ($000/yr 

Solvent Emissions Control1 ed (~~/?r !g 

Per~ent Emission Reduction 

Cost (credit) per Mg of VOC 

controlled ($1~9) 

(uip lank) (Dip Tank) W (Oven) (Oven) ,Lo 

Alternative I1 - Exhaust Gas Treatment Thermal Incinerator Carbon~dsorption Oven ~ermal Incinerator Carbon Adsorption Over; 

with Primary Solvent at and with Primary Solvent at and 

Heat Recovery Fuel Valve Tank tieat Recovery Fuel Valve Tank 

h Direct Operating Cost ($000/yr) 

Capital Charges ($000/yr) 

Net Annual ized Cost ($000/yr) 

Solvent Emissions Control led (Mglyr) 

Percent Emission Reduction (Total) 

Cost per Mg of VOC Controlled ($/Mg) 

-

a~ne

i 

color system operating 1920 hours/year and coating metal shelves - no primer. 

b~xcludes metal pre-treatment and dry-off oven costs (references 1,2). 

xist sting tank cleaned and corrosion protection (reference 5). 

d . . Existing solvent dip coating system replaced by EDP system (references 1,2,7). 

e~eferences 1,Z. 

f~eference8. 

g~g= Megagram = 1 metric ton 

h~eferences 1,2. 
Net annual savings appear possible by converting to higher sol ids 

coatings due mainly t.o the estimated lower applied film cost when compared 

to conventional sol vent coatings . 

As noted in Table 3-1, coating material costs for waterborne are 

slightly higher than solvent coatings for the same volume solids. This 

results in higher annual costs when converting to waterborne coatings. For 

lines converting to powder coatings some energy, waste disposal and direct 

labor savings were estimated. " However, as indicated in Table 3-2, it is 

assumed that metal furniture requires a coating thickness of 50 NTI (2 mils) 

when coating with powders. This factor greatly diminishes any materials cost 

savings normally expected with powder coatings when compared to conventional 

solvent coatings. 

In the case of incineration of oven emissions, annualized costs are 

mainly costs for fuel required to raise the temperature of the oven exhaust 

from 160°C to 760°C and capital charges. Annual costs for carbon adsorption 

of sp,ray booth exhausts are slightly reduced (less than 2%) by crediting recovered 

solvent at fuel value. Large capital investments required for carbon 

adsoription systems are reflected in high capital charges. In general, net 

annualized costs for controlling VOC emissions from electrostatic spray coating 

lines appear to be lowest when converting to higher solids or waterborne 

coatings and greatest when combining incineration and carbon adsorption 

of oven and spray booth exhausts, respect.ively. 

3.2.2 Dip Line -

Capital and annual ized costs for the control a1 ternatives considered 

for existing dip 1ines are summarized in Table 3-4. The incremental capital 

costs for converting the dip line to waterborne appear to be small when compared 

to the baseline investment. Costs assume that the existing dip tank is used 
and some corrosion protection is required. On the other hand, dip lines 

converting to the waterborne electrocoat will require significant investments 

when instal 1 ing the el ectrodeposi tion appl ication system. Capital costs for 

oven exhaust incineration and carbon adsorption of dip tank exhausts for the 

model dip lines are approximately two times greater than convertjng to 

electrodeposi tion. 

Increased annualized costs for controlling dip coating lines by conversion 

to waterborne are primarily a result of higher material costs for the waterborne coating. For electrodeposition, lower applied film costs for the 

el ectrocoat material he1 p over-ride increased electrical costs associated 

with the electrodeposition system. '* A1 though incremental direct operating 

cost increases for the electrodeposition system appear to be minimal in 

Tab1 e 3-4, capital charges associated with the 1 arge capital investment 

requirements are much higher than waterborne conversion. Total annualized 

costs for incineration and carbon adsorption presented in Table 3-4 are about 

two times greater than incremental annualized costs for electrodeposition and 

about five times greater than waterborne annualized costs. 

3.3 COST-EFFECTIVENESS 

The cost-effectiveness of the alternative control measures considered for 

electrostatic spray and dip coating lines are summarized in Table 3-5. For 

electrostatic spray lines it appears to be more cost effective to reduce VOC 

emissions by converting to a low solvent coating, either waterborne or higher 

solids. Conversion to powder coating will result in the highest emission 

reduction achievable yet is not nearly as cost-effective as waterborne or 
7: 


Table 3-5. COST EFFECTIVENESS OF ALTERNATIVE CONTROL METHODS 

Spray Coating Line: $/Mg of VOC Control 1 ed 

278,000 rn2/yr. 4,500,000 m2/yr. Reduction in VOC 

A. Conversion to Higher Solids Coating (1 58)* (226 86 

B. Conversion to Waterborne coating 

C. Conversion to Powder Coating 

D. Thermal Incinerator on Oven & 

Carbon Adsorber on Spray Booths 

E. Carbon Adsorber on Spray Booth 

F. Thermal Incinerator on Oven 

W 

I Dip Coating Line: $/Mg of VOC Control 1 ed ---I 

N 650,000 m2/yr. 2,100,000 rn21yr -

% Reduction in VOC

G. Conversion to Waterborne 

H - Conversion to El ectrodeposi tion 

1. Thermal Incinerator on Oven & 

Carbon Adsorber on Spray Booths 

(Dip Tank) 

J. Carbon Adsorber on Surav Booths 

(bid Tank) 

K. Thermal Incinerator on Oven 

*Parenthesis indicates credit 
Figure 3-7 . Cost-Effectiveness versus Surface Area Coated 

(Base1 ine=25% Sol ids Conventional Coating) 

-Electrostatic Spray 

--.--- Dip 

NOTE: Refer to Table 3-5 

for code to letters 

Mi 11 ion Square Meters/Year 
higher solids conversions. In fact, at higher production rates the results 

appear to indicate that it is more cost-effective to incinerate oven exhausts 

and treat booth exhausts by carbon adsorption than convert to powder coatings. 

For dip coating lines, converting to an alternative coating appears to be a more 

cost-effective measure for reducing VOC emissions than incineration and carbon 

adsorption. Although the model analysis estimates a 92% reduction in VOC by 

converting to electrodeposition, the cost per megagram of VOC controlled is 

higher than waterborne conversion over the range of sizes studied. Costeffectiveness values from Table 3-5 and an additional estimate of cost-effectiveness for each application method were plotted and the results are displayed 

in Figure 3-1. Smooth curves drawn through the points depict how costeffectiveness is expected to vary with square feet coated per year. 

3.4 SUMMARY 

Based upon the model analyses performed on electrostatic spray and dip 

coating lines applying finishes to metal shelves, VOC reductions of 80 percent 

or greater can be achieved at the least cost per unit weight of VOC controlled 

when using existing (modified) application equipment while applying low solvent 

coatings. For electrostatic spray 1 i n e s , converting to higher sol ids coatings 

(70% or greater) or a waterborne coating appears to be the most cost effective 

control a1 ternative. The latter a1 ternative, however, may have 1imi ted application 

due to the technical and cost implications associated with some line configurations. 

For clip coating lines conversion to waterborne, where applicable, seems the 

most cost-effective alternative. Controlling VOC emissions by incineration 

and carbon adsorption appears to be the least cost-effective alternative for 
the m~odel 1 ines considered. 

Finally, it is stressed that the resu 1 ts of this ana lysis are intended 

only to serve as guidance in assessing the relative costs of a1 ternati ve 

control schemes. Individual requ irements and specifications of a particular 

coating 1ine may requ ire ana lysis when determining costs for that specific 

coating line. 
3.5 REFERENCES 

1. Second Interim Report on Air Pollution Control Engineering and 

cost study of the Genera1 Surface Coating Industry Prepared by 

Springborn Laboratories, Inc. mder EPA contract no. 68-02-2075 

August 23, 1977 

2. Second Interim Report on Air Pollution Control Engineering and 

Cost Study of the General Surface Coating Industry - Appendices 

A & B. Prepared by Springborn Laboratories, Inc. under EPA contract 

no. 68-02-2075, August 23, 1977 

3. Personnal communical;ion to John Pratapas , USEPA/SASD, from Bi 11 

White - DeVilbiss, Toledo, Ohio, November 29, 1977 

4. Trip Report - Keller Industries, Milford, Va. from W.B. Kloppenburg 

of springborn Laboratories to avid patrick, USEPAIESED, ~ebrdar~-

23, 1976 

Personnal communication to John Pratapas, USEPA/SASD, from Margo 

Oge - Springborn Laboratories, April 29, 1977 

DeVilbiss Case History - Powder coating Technical Handbook PC-1001 

July 15, 1974 

Personnal communication to John Pratapas, USEPA/SASD, from James 

Johnson, The Shaw-Walker Co. Muskegon, Michigan, November 29, 1977 

Personnal communication to Vera Gal lagher, USEPA/ESED, from L. R. 

LeBras, PPG Industries, Pittsburgh, Penn. , September 22, 1977. 

Personnal communication to John Pratapas, USEPA/SASD, from Frank 

Merlotti - Steelcase, Inc. Grand Rapids, Michigan, June 9, 1977. 

Personnal communication to John Pratapas, USEPA/SASD, from Clyde 

Speir - Lyon Metals, Aurora, I1 1 inois, December 8, 1977. 

H-igh Solids Coatings Volume 2, No. 2, Technology Marketing Corporation 

Stamford, Conn. , Apri 1 1977 

Capital and Operating Costs of Selected Air Pollution Control 

Systems, GARD, Inc., Niles, I:llinois, EPA contract no. 68-02-2072, 

Mily 1976 

Control of Volatile Organic Emissions from Existing Stationary 

Sources - Volume I: Control Methods for Surface-coating operations. 
4.0 ADVERSE AND BENEFICIAL EFFECTS OF APPLYING TECHNOLOGY 

4.1 POWDER COATINGS 

There are several advantages obtained after a facility is converted to 

apply powder coatings besides the substantial reducti on in emissions. 

There are almst none of the solid or liquid waste disposal costs 

or problems that are often encountered when using sol vent-borne coatings. 

Powders do not, require the purchase of additional sol vents to 

control viscosity or to clean equipment. 

Conversion tci powder coatings will reduce energy requirements of 

the spray booth because the large volumes of fresh air required for solventborne coatings are not required. (A1 though the lower explosive limit is 

higher than for sol vent, the reduction in air volumes is possible mostly 

because the spray booth is not occupied.) By using an efficient particulate 

collector, the spray booth air may be recycled into the working area ,further 

reducing energy usage for air conditioning or heating. It has been estimated 

that a 35-50 percent overall reduction in energy consumption can be achieved 

when a single coat application is replaced with one coat of powder, and a 

55-70 percent reduction is possible when a two-coat application is replaced 

with a single coat of powder. 1 

Powder coatings also have an advantage in providing good coverage 

of the metal piece and masking imperfections or welds in the metal. 

Although powder overspray can be reclaimed at about 98 percent 

efficiency, not a1 1 the reclaimed powders can be reused. Reclaimed powder 

containing a buildup of powder fines will have to be discarded, and the 

larger and heavier granules will have to be reprocessed again before they 

are suitable for reuse. 2 3 

4-1 
There are disadvantages encountered when applying powder coatings. 

A1 1 appl i cat ion equipment, spray booths and associated equipment 

(and often ovens) used for llquid syste~~is must be 'replaced. This will then 

limit the coating flexibi 1 ity of the metal furnjture manufacturer because he 

will only be able to apply powders. 

Coating film thickness of less than 2 mils has not been successfully 

obtained with powders on a production line basis. 

Color changes for powder require about half an hour downtime. Metal 

furniture facil i ties requiring numerous color changes during the day would 

have to greatly curtail production capacity. Color changes may be shortened 

if the powders are not reclaimed in their respective colors resulting in a 

coating usage efficiency of about 50 to 60 percent. Those facilities which 

apply many colors but can schedule their operations to run a single color 

for a given time period may still find powder an economically acceptable 

a1 ternative. 

No one can yet provide the so-called metal1 ic coatings in ponder, 

Color matching during manufacturing of powder is difficult. 

Powder fi lms have appearance 1 imitations. 

Recesses are difficult to cover effectively due to the Faraday caging 

effect. 

Excessive humidity during storage or application can affect the 

performance of powder. 

Powder coatings are also subject to explosions,as are many particulate 

dusts 4 

4.2 ELECTRODEPOSITION 

Several other advantages, in addition to reduced VOC emissions , accrue 

from converting to el ectrodeposition. 
The major one is good qua1 ity control as a consequence of the fully 

automated process. 

It provides a very high transfer efficiency. 

It also provides excel lent mating coverage and corrosion protection 

because the paint parti cl es penetrate into the smal lest recesses. (However, 

because the coverage is so uniform, electrodeposition does not mask 

imperfections in the substrate as well as other appl ication techniques). 

The low solvent content permits lower vent 

reduced energy consumption. 

The dry off oven that normally follows the 

longer required a1 tho~gh an additional rinse with 

ilation rates resulting in 

pretreatment step is no 

deionized water is essential. 

Conversion to electrodeposition may also result in lower insurance costs 

because of reduced f i re and toxi city hazards. 

There are severa 1 disadvantages to the el ectrodepos i tion process. 

One is that it requires a unique type of application equipment. As 

a result, electrodeposition can be capital intensive when used on small 

scale production 1 ines. 

If the hooks which hold the metal furniture pieces are not properly 

cleaned or hung, the electrical contact may be faulty and the coating will 

not adhere to the metal. 

Conversion to clectrodeposi tion coating will increase electrical consumption. The amount, however, will depend on the former application system, 

size of the electrodeposition bath, type of furniture pieces coated, and 

thic:kness of the coating. Energy is required for the coating system, 

refrigerati on (to overcome the heat generated by the el ectri cal process), to 

circulate the bath, and purification of the bath. If a spray operation is 
rep1 aced by 

solid and 1 

elimination 

electrodeposi tion, some credit may be a1 lowed for decreased 

iquid wastes and the reduced energy requirements attributable to 

of the spray booth. 

4.3 WATER-BORNE COATINGS 

There are seveml advantages to converting to water-borne coatings. 

The greatest is that existing equipment, whether for cpray, flow, ordip 

coatina, can be used. (Some parts of the coatinq equipment, however, may have 

to be protected from corrosion). 

Water-borne coatings may be thinned with water,and coating equipment 

can be cleaned or flushed with water rather than organic solvent. Unlike 

with organic coatings, however, water-borne coatings must be cleaned off 

application equipment when still wet since they are not soluble in their 

carriers when they become dry making cleanup with organic solvents necessary. 

A potential disadvantage of water-borne coatings is that energy consumption may increase because some water-borne coatings must be flashed off 

under controlled humidity, and the ovens may have to be lengthened to 

several stages to compensate for the slower evaporation rate. However, this 

energy increase is pdrtially offset by the reduced oven exhaust and perhaps 

the lower curi ng temperature typical of many water-borne coatings. 

The water-borne coating is more sensitive to temperature and humidity, 

both during application and flashoff. The flashoff air circulation may need 

to be increased to a1 low a uniform evaporation rate of water during high and 

5 low humidity conditions. 

Disposal of solid or liquid waste may be difficult. 

In dip or flow coating processes, an additional rinse may be required 

to avoi d contami nati cln of the coating bath. 
Overspray froni water-borne does not harden as rapidly making sludge 

hand1 ing more difficult. 

Proper pretreatment is critical to prevent flash rusting of metal 

furniture. 

4.4 HIGHER SOLIDS COATINGS 

Higher solids coatings can be applied with existing spray equipment. 

These coatings are presently limited to about 65 volume percent solids, 

a1 though research is being done; both on high solids (65-80 percent) 

coatings and on improved application equipment. Conversion to higher solids 

coatings can reduce energy requirements. Air flow in the spray booth can be 

reduced because less organic solvent is applied for each dry mil of coating. 

The oven energy requirements may also be reduced. Sol id and 1 iquid waste 

may decrease since less coating is applied per dry mil. However, the tackiness 

of some high-sol ids coatings may make cleanup more difficult.6 Although the 

sol vent content is reduced, thus reducing the level of toxicity, there is a 

potential health hazard associated with isocyanates used in some high-solid, 

two-component sys terns. 

4.5 CARBON ADSORPTION 

There are no metal coating facilities known to use carbon adsorbers to 

redwe VOC from appl i cati on and flashoff areas. This technology, however, 

is technically feasible for such applications and is well documented. A 

potenti a1 disadvantage is that it will increase the requirements for electrical 

and fuel energy. The amount will depend or1 application, size of adsorber, 

and concentration of the organics entering the carbon bed. Any decrease in 

air flow and accompanying increase in VOC concentration from the coating 

application and flashoff areas will reduce the energy demands. 

15 gercent LEL 
I. "tcc~nornir.71Ac,tI 1cdt:on of' Powder Coating. Powder Cinishing World 

Paqes 13-62, CtL- quart~v. 1976. 

/*. era L 2 7echrlicai Director, PPG Industries, Inc., Pittsburgh, 

?a. Letter +i'r i'ti "riiiagher :n cornmerit of this document. Letter 

ddted Septeni er . , 1'17'. 

. Wrnbos, La\: L. J?.., :teelcase, Incarporated, Grand Rapids, Michigar. 

Letter to ber'c; ii i l iilher. in coment of this document. Letter dated 

Au~I:s~ 3: , '~?i 

4. Op. Cit. i- bra; 

5. "lzlater-Bor-ne '-7~-~~i iol~land Dip," Prod~cts Finishing. Pages 73-76. 

February 13'7. 

6. "Questicn Cowe: . ' riigh-Sol ids Coatings, Volume I, No. 3. July 1976. 

i'. Curnbustl or E +i31nr-~-~ng Ai r Prehedter Wellsville, New York, Report of 

Fwl Requirement:, -a~ital Cost and Operating Expenses for Catalytic 

~1ndPherrw?; 7ftewurn~r.s. EFA Con tr-dct Report No. EPA-450/3-76-031 . Septernb~y :976 
5.0 MONITORING TECHNIQUES AND ENFORCEMENT ASPECTS 

This chapter discusses the recommended emission limit, the monitoring 

techniques and enforcement aspects of low polluting coatings and add-on 

control equipment. 

As stated in the preface, there is no universal VOC emission control 

technique applicable for the industry as a whole because of the variety of 

metal furniture products manufactured. Hiowever, metal furniture faci 1 ities 

have certain similarities which permits grouping them for use of certain 

control techniques. For example, ifa facility has no difficulty with 

Faraday caging, applies a limited number of colors, can run a single color 

for a given time period, and a coating film thickness of greater than two 

m i 1s is not objectionable , powder could be the best control technique. 

If a facility runs only a few colors on a large production basis, electrodeposition would be the best control technique. However, if a facility must 

color match or change colors frequently, water-borne or higher-sol ids coatings 

would be the best choice. The recomnended emission 1 imi t(3.O lbs of organic 

solvent per gallon of coating, less water), as stated in the Preface,is based 

on the application of water-borne or higher solids coatings. Sample calculations 

to verify compliance with this emission limit are shown in Appendix A. 

Previous control regulations for VOC have included limitations on the 

reactive organic solvent or have stipulated that a minimal reduction be 

achieved through add-on control equipment. While either approach is acceptable, 

maximum solvent content is a more pra~tical basis for those surface coating 

operations where use of low-solvent coatings will generally be the compliance 

technique. 

5-1 
For metal furnl ture indu%tries, it .Is recommended that emission 

limitations be expressed in terms of organic solvent content since these 

values can be determined with re1 ati vely simple analytical techniques. 

Limitations in VOC may be expressed in terms of mass or volume and 

may be based on the (entire coating (including organic solvent) or only on 

paint solids. In this guideline, limitations are expressed as the allowable 

mass of organic solvent per unit volume of coating (kgs per liter of coating 

or lbs per gallon of coating) as it is delivered to the coating applicator. 

Wa'ter in the coating is subtracted. The principal advantage of this format is 

that enforcement is relativeTy simple. Field personnel can draw samples and 

have them analyzed quickly. A disadvanta,ge is that the relationship between 

the solvent fraction and srganic emissions is not linear. If the solvent 

content is expressed in terms of mass of organic solvent per unit volume of 

paint solids (kgs per liter of solids or lbs per gallon of solids), the 

disparity disappears . The relationship is 1 inear and more readily understood 

e.g., a coating cont(3ining 2 lbs of organic solvent per gallon of solids 

relleases twice as much organic solvent as one of 1 lb per gallon. The 

disadvantage of this format, however, is that the analytical methods are more 

complex. Appendix A -in "Control of Volatile Organic Emissions -,'ram Existing 

Stationary Sources - Volume I1 : Surface Coating of Cans, Coils, Paper, 

Fabrics, Automobiles and Light: Duty Trucks" presents ASTM methods for 

determination of the pounds of organic sol vents per gal Ion of coating (minus 

water). 

Other options sllch as pounds or gallons of organic solvent per pound of 

coating are generally less desirable although they may be entirely appropriate 

for a given industry. Basing limitations on the mass of coating or paint 
solids is not recommended because the specific gravity of coatings tends 

to vary widely with the degree and type of pigment employed, Highly 

piqmented paints have much greater density than unpigmented clear coats 

or varnishes, 

This limitation for coatings assumed the facility merely converts 

from use of an orqanic-borne coating to a coating low in organic solvent. 

It does not consider any small or signifitcant reduction in VOC emissions 

which may result from a decrease in film thickness or an increase in 

transfer efficiency of a coating. One example of such reduction may be 

where a facility is applying a convention~il coating at 1.2 mils film 

thickness, and converts to a coating contdining less organic solvent than 

the conventional coating but which does not quite meet the recommended 

emission limit. However, ifthe new coating has better hiding power and can 

be applied at only 0.8 mils film thickness, the decrease in film thickness can still result in a proportional reduction in VOC emissions as 

compared to a coating which meets the recommended emission limit. Other 

examples would be if 3 facility converts from a manual conventional spray 

application (at a transfer efficiency of 40-70 percent) to an automated 

electrostatic spray sistem (at a transfer efficiency of 70-90 percent), or 

from any spray system to a flow or dip coat system (at a transfer efficiency 

of at least 90 percent). Some incremental reduction in VOC emissions will 

be realized. This reduction in VOC content can be included in the overall 

system to provide the equivalent reduction in emissions, 

In those few far: lities where add-on control equipment is a more likely 

optjon, it may be more appropriate to state emission limits in terms 0f 

cont;rol efficiency across the incinerator, adsorber, etc. Where limitat ions 
are expressed only in terms of the coating content, it will be necessary 

to determine mass emissions from the control system and relate them to 

the quantity of coatings applied during the test period. It is often 

difficult to detennine the consumption of coatings during any given period 

and to determine the amount of organic solvent directed to the control 

device. Chapter 5 of "Control of Volatile Organic Emissions from 

Existiny Stati 0nar.y Sources - Vol ume I : Control Methods for Surface 

Coating Operat ions" presents test methods for add-on control devices. 

When add-on type devices are selected as the compliance method, the air 

pollution control agency should require that the coating lines be equipped 

with an approved capture device to assure effective control. The capture 

system will 1ikelv have to be custom designed to accommodate the plant-toplant variables which affect performance. When reviewing the design of 

such a syste~n, however, the air pollution control official must consider 

requi rements imposed by the Occupational Safety and Health Administration 

and the National Fire Prevention Association. 

Some coatings will emit a greater amount of VOC than merely its 

solvent content. This incremental VOC may come from three possible sources. 

The first IS the possibil ity that some of the monomer may evaporate. A1 so, 

if it reacts by the condensation polymerization, the evolution of byproduct compounds may be a compounding factor. Finally, it has been reported 

that the industry is using increasing quantities of "blocking agents" which 

are released from the polymer matrix during the curing process. 

There are now no approved analytical methods certified by the agency 

for determining the quantity of VOC emitted by such reactions, although 

certainly the orgc~nic inass emission rate could be determined by expensive 
and sophisticated analytical techniques. The more practical means of 

quanti fying the contribution of the polymerization reacti on to the 

overall emiss ion ~~roblem would be by contacting the manufacturer of 

the coating. Certainly, his know1 edge o f the fundamental chemical 

mechanisms involved would allow calculat ion of an emission rate based 

on the chemical reaction. 

This emission will occur during the cure (if at all) which is usually 

temperature initi(3ted by the oven. If' the oven is controlled by an 

incinerator, then verification of the efficiency of the device should be 

sufficien~. to assure compliance with the coating regulation. 
APPENDIX A 

SAMPLE CALCULATIONS OF CONTROL OPTIONS 

This appendix aids the local agency in determining ifa coating propo'sed for use by a metal furniture f a c i l i t y w i l l meet the recommended 

emission limit of 0..36 kilograms of VOC per liter of coating applied, 

(3.0 1 bs/gal ) excluding any water that the coating may contain, The 

purpose of excluding water is to preclude compliance through dilution with 

water. This appendix also explains how t.o compare the actual VOC emissions 

from a facility regardless of the type of' low-polluting coating or add-on 

control device used, 

The purpose of dl1 coating operations is to cover a substrate with a 

film that provides both corrosion resistance to the substrate and esthetic 

appeal. Therefore, the rational basis for specifying an a1 lowable VOC 

emission limit would be in units of coating volume ( e.g, grams of VOC per 

square meter (1 bs/sq .ft) per unit thickness of film). However, the 

complexity of any analytical method which would provide a measurement of the 

volume of a cured coating precluded this approch. As a compromise, the 

recommended 1 imitations were developed in kilograms (lbs) of VOC per unit 

volume of uncured solids and organic solvent. Mathematically, then, the 

emission factor (ef) for a coating would be expressed as: 

volume fraction organic solvent)(average organic solvent density) (1) ef= L,---- vo ume fraction of solids + volume fraction of organic solvent 

or 

(2) ef = lvol ume fraction organic solvent) (average organic solvent density) 

1 - volume' fraction of water 
The following exa,mples show the use of these equations to determine 

the emission factor for both organic solvent-borne and water-borne coatings. 

CASE 1 : Determine the emission factor for an organic solvent-borne coating 

which contains 40 percent organic solvent, 

Therefore: ef = (-*40)(0.88 kg/liter*) 1-0 

= 0.35 kg/l iter (2 -94 1 bs/gal ) 

Since the emission factor is less th<an the recommended limit of 

0.36 kg/liter (3.0 lt:~s/gal), this coating is in compliance. 

CASE 2: Determine the emission factor for a water-borne coating containing 

75 percent solvent. 

Since 80 percent of the solvent is water, the respective volumes of 

water and organic solvent may be calculated as shown: 

Volume water= .80 x .75 liter = .6 liter 

Volume organic solvent= 0.75 liter - .6 liter = .15 liter 

-

= 0.32 kg/liter (2.64 lbslgal) 

This coating also has an emission factor less than the recommended limit 

and would comply. 

The level of control represented by 0.36 kg/liter of coating 

(3.0 lbs/gal) less water can also be achieved with a conventional high 

organic solvent coating ifsuitable add-on control equipment is installed. 

However, this method of determining the equi val vent emission 1 imi t factor 

is not as straiqhtforward as the previous two cases and must also consider 

the volume of solids in the coating. 

&Tis' density is considered typical and is equal to 1.36 1 bs/gal . 
CASE 3: Determine the emission factor for a conventional organic-borne 

coating containing 75 percent organic solvent. 

However, this l iter of coating contains only 0.25 1iter (gallon of 

solids whereas the coating which represents the recommended emission limit 

of 0.36 kg/liter (3,0 lbs/gal) contains 0.60 liter (gallon) of solids. 

(This can be back calculated from the recommended emission limit in this 

manner, ) 

-

(x)( 0.88 kg/liter) i.e. 0.36 = 

x = 0.40 volume percent organic solvent. 

Therefore fraction of solids = 1 - x = 0.60 

On a unit volume of solids basis, the conventional coating contains: 

0.66 kg organic solvent - 2.64 organic sol vent 22 1bs VOC 

0.25 1iter sol ids 1 iter sol ids gal , sol ids 

And the recommended limit reference coating contains 

0.36 kg organic solvent - 2.6 kg organic solvent 5 lbs WC 

'0.6 liter solids liter solids 
Consequently, in order for the conventional coating to emit no more VOC 

than the reference coating, the add-on control device must capture and 

destroy (or collect) 2.04 kg of sol vent per 1 iter of solids applied 

(2..64 - 0.6). This will require a control system that is at least 78 

percent efficient. 5ince the add-on control devices can often operate at 

90 percent efficienc,~ or greater, the agency must insure that at least 

85 percent of the VOC emitted by the coating is captured and delivered to 

the add-on control device. Since it will normally not be practical to 

attempt the complex analytical program essential to develop a 

material balance around the coating appl icati on and flashoff areas and ovens, 

the agency will riornial ly certify an acceptable capture system based on good 

engineering practice. 1 
APPE:NDIX A REFERENCE 

1. Young, Dexter E. , Environmental Protecti on Agency, memorandum concerning 

requirements for ventilation of spray booths and ovens. Dated March 10, 

1977. 
--- - - -- 

-- - -- -- 

I 

TECHNICAL REPORT DATA 

-- (Plrase read IarYuctzons on the rer,erse belore completing/ 

' RE@%&50/2-77 -032 1 7 

3 RECIPIENT'S ACCESSIONNO. I--- I

- I --- - -------- --- 5 REPORT DATE 

ControlofVolatileOrgar~icEmissionsfromExisting December1977 

Stationary Sources 6. PERFORM~NGORGAN~ZAT~ONCODE - Volume I I I : The Surface Coating 

of Metal Furniture 

8. PERFORMING ORGANIZATION REPORT NO. 

OAQPS NO. 1 ,2-086 

10 PROGRAM ELEMENT NO 

Management 

Office of Air Qua1ity Planning and Standards 

North Carol ina 2771 1 _ ___________I---

13. TYPE OF REPORT AND PERIOD COVERED 

WGAGENCY CODE 

16 ABSTRACT 

This report provides the necessary guidance for development of regulations 

to 1imi t volatile organic compound (VOC) emissions from the coating operations 

of metal furniture industry, This auidance includesan emission limit which 

represents Reasonablv Available Control Technoloqy (RACT), methods by which 

RACT can be achieved, and monitoring and enforcement aspects. 

- 17. KEY WORDS AND DOCUMENT ANALYSIS - ----- - _ - - -- ----- a DESCRIPTORS ~.IOENTIFIERS/OPEN ENDED TERMS c COSATI F~eld/Group 

Air Pollution Air Pol 1 ution Control 

VOC Emission Limits Stationary Sources 

Metal Furniture Industry Organic Vapors 

Regulatory Guidance 

18. DISTRIBUTION STATEMENT (This Report) 21. NO. OF PAGES t 
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20. SECURITY CLASS (This page) 22. PRICE 

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I I EPA Form 2220-1 (9.73) 
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