## EPA-450/2-77-032 December 1977 (OAQPSNO. 1.2-086) GUIDELINE SERIES



# CONTROLOF

# VOLATILE ORGANICEMISSIONS FROM EXISTING STATIONARY SOURCES VOLUME 111: SURFACE COATING OFMETAL FURNITURE

l

## J.S.ENVIRONMENTALPROTECTIONAGENCY OfficeofAir andWasteManagement OfficeofAir QualityPlanningand Standards Research Triangle Park,NorthCarolina27711

## EPA-450/2-77-032 (OAQPS

## NO. 1.2-086)



# CONTROLOFVOLATILE ORGANICEMISSIONSFROMEXISTING STATIONARYSOURCES VOLUME 111: SURFACECOATING OFMETALFURNITURE

EmissionsStandards and Engineering Division Chemical and PetroleumBranch

1.1;.ENLIRONMENTAI, PROTECTION AGENCY Officeof Air and F'asteManagement Officeof Air Quality Planning and Standarcl~ Rerearch TrianglePark, North Carolina 27711 December 1977tjAQPS GUIDELINE SERIES The guideline series of reports isbeing issued by the OfficeofAir 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 forthe maintenance of air quality. Reportspublished in this serieswill be available

-- as suppliespermit

- from theLibrary 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.

PublicationNo. 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 volati1 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 wi11 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 applicable 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 solvent 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 available control technology (RACT)


## . Reasonable avai

### 1able control technology isdefined as the lowest emission limitthat a particular source is capable of meeting by the application of control technology that is reasonably availabl e considering technological and economic feasibi1i ty Itmay ?!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, itmust be cautioned that the emission limits reported inthis Preface are based on capabilities which are general to this industry, but may not be applicable to every facility.

Affected Faci

### 1it. .- Recommended Limitation kg oforganic solvent 

### Ibs of organic solvent emitted per liter of emitted per gallon of coating (minus water) coating (minus water) Metal Furniture Coating 

### 0.36 

### 3.O Line 'This emission litnit isbased on the use of low organic solvent coatings. It can also be achieved with water-borne coatings and isapproximately 13quivalent (on the basis of solids applied) to use of an add-on control devicewhich 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 facilities will seek to meet future regulations through 

### the use of coatings which are low inorganic solvent.GLOSSARY

Prime coat means the first 

### filmof coating applied ina two-coat operation.
* Topcoat means the final filmof coating applied ina two-coat operation.
* Single coat means only one filmof coating isapplied on the metal substrate. Faraday caging means a repelling force generated during electrostatic spraying of powders incorners and small enclosed areas ofmetal substrate, Blocking agent means an agent which is released from the polymer matrix during the curing process. It is normally an organic radical and splits 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,

### CONVERSION FACTORS FOR METRIC UNITS
Equival ent Me,tric 

## - Unit Metric Name English Unit Kg kilogram (loJgrams) 2.2046 lb 1 iter 1iter 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

Inkeeping with U.S. 

### Environmental Protection Agency pol

### icy,metri c units are used inthis report.. These units may be converted to common English units by using the above conversion factors. Temperature indegrees Celsius (CO)can be converted to temperature indegrees Farenheit (OF) by the following formula:

to = 

### temperature indegrees Farenheit to, = 

### temperature indegrees 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 Annualized 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

# .......................... 3-164.0 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 TECHNIQUESAND 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 volati7e organic solvent (VOC) emissions which can be expected from these coatings.
1.1 

### GENERAL DISCUSSION Metal furniture ismanufactured for both indoor and outdoor use, and may be divided into two general categories; "business and institutional

## ", and "household! Business and institutional furniture ismanufactured for use

inhuspitals, 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. A1though there are more than twice as many manufacturers ofmetal household furniture, on the average, those that manufacture metal business and institutional furniture are twice as large. About half ofthe 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, she1ving, file cabinets, lamps, room dividers and many other similar products. Metal furniture plants 

### are 1 ocated throughout the United States, however, Illinois, California, Michigan, New York and Pennsylvania contain over 50 percent ofthe plants inthe industry. The Environmental Protection Agency's Region 

### V contains about 30 percent ofthe industry, Regions I1and 

### IVabout 16 percent each, and Regions II1and IXabout 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 ofmetal furniture facilities vary. Some plants manufacture metal furniture to be sold directly to consumers through retail stores. Incontrast, "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 linevaries depending on the furniture coated, thetype 01' coating application used, and on how many coats are applied. The coating 1ine can have a 

### steady production rate ranging from 8 

### to 

### 24 feet per minute, or the furniture pieces may be coated sporadically. Coatings applied ineach plant vary with personal preference, type of furniture, appl

### ication technique, pretreatment, and end use. Conventional coatings are applied at 

### 0.7 to 1.5 mils thickness. Most ofthe coatings
are enamels although some lacquers are also used. Some metal furniture pieces are coated with metal

### 1ic coatings. The most comnon coatings are alkyds, epoxies and acrylics containing various mixtures of ketones, aromatic, a1iphatic, terpene, ester, ether and alcohol solvents. The coatings
are often purchased at higher solids 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 oroutdoor furniture. They must have good adhesion properties toavoid 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 

### ortotally 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 entirewash section is omitted and the pieces are c1 eaned in a shot--blasting chamber or organic solvent cleaning operation. Most metal furniture isfinished with a single-coat operation. Some pieces, however, require a prime coat application due to the topcoat formulation orthe end-use 

### ofthe piece. The prime coat may be applied by electrostatic or conventionall spray, dip orflowcoating techniques. The substrate with the prime coat then goes through a flashoff period to avoid popping of the f ilrn when the coating isbaked. The prime coat is usually bdked inan oven at about 160" to 200°C (300"-400°F). The topcoat or d single coat may be applied by spraying, dipping or flowcoating. Ifa ~lant manufactures furniture in a variety of colors, necessitating frequent color changes, the coating isusually sprayed either electrostatically or by conventional airless or airspray methods. 

### If a plant manufactures furniture inonly one ortwo colors, the coating often 

### isapplied either by flowcoating or bj dipping. Electrostatic spray coating may be performed either manually orautomaticallya1though no st spray coating inmetal furniture facilities 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 ofapplication is
more efficient than the conventional air or air1 ess spray methods because there isless overspray thereby reducing the amount of paint that must be sprayed and the VOC 

### that evaporates. Spray coating is performed ina 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 

### isoccupied by people,on type ofspray booth, and on size ofspray booth and openings. The minimum air ve'locities are prescribed by OSHA to assure capture ofpaint particles and insure the VOC concentration does not exceed thethreshold limitvalues. Dip coating isthe immersion of pieces into a coating bath. After withdrawal, the excess coating isallowed todrain back intothetank. 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 thesink, is filteredand pumped hack into a coating holding tank. The coated furniture is usually baked in an oven but insome cases is airdried. The flashoff area 

### 1ies between the coating application area and the oven. This allows solvents to rise slowly inthe coating film, thus avoiding popping of the filmwhen the coating is baked. The fraction of thesolvent which 

### evaporates inthis 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 airflow rate from the ovens 

### will depend on the type and size ofthe oven, and the size ofthe 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 ofthe lower explosive limit 

### (LEL) ofthe evaporating solvents. This means that about 10,000 scf o f a i r is required toevaporate 

### 1 gallon of solvent. Some facilities have been allowed tooperate at higher 

### LEL's (around 50 percent), however, if

### proper 

### LEL monitoring equipment is used. Many metal furniturebaking ovens presently operate between 5-15 percent of the LEL. 

### The principle reason for maintaining such low concentration levels isthat the oven must be maintained under negative pressure to avoid spillage of fumes into the plant. This requires a 

### 15mpm (50 fpm) to a 45 fpm (1 50 fpm) airvelocity 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 ofcoated metal furniture pieces, the airflow required tomaintain theoven under negative pressllre may exceed the airflow required to maintain the oven below 

### 25 percent 

### LEL. Volatile organic compounds are emitted from the coating area, the flash

# I
off area and the oven. It 

### isestimated that in spray applications, about 65-80 percent ofthe VOC 

### are released from the spray booth and the flashoff 

### , 1 

### area, and the remaining 20-35 percent from the oven. For a dip orflowcoat 

# i application, it 

### isestimated 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 linedue to its construction and the type ofcoating 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.-- 

## -- Tab1e 1-1 DISTRIBUTION OF 

### VOC EMISSIONSaFROM METAL FURNITURE COATING LINES

Appl icat

### ion Application and Method 

### Flashoff Area Oven Electrostatic Spray Conventional Airor Airless Spray Dip Flow

a The base case coating isapplied 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 literof coating 

### (5.5 lbslgal) minus water.20 40 60 80 100 120 140 160 180 200
lbs oforganic solvent (VOC) emitted per hour

Figure 1-2. Re1ati onship between 

### VOC emission, exhaust flowrates and 

### VOC concentrations.

### 1.3 

### REFERENCES 

### 1. Sherman, Michael, S., 

### Director of Economic and Market Research, Summer and Casual Furniture Manufacturers Association, 

### 1etter 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 a1so discusses othermethods of applying coatings (powder and electrodeposition) which result in low VOC 

### emissions.
Tab1e 2 SUMMARY 

### OF 

### APPLICABLE CONTROL 

### TECHNOLOGY FOR METAL 

### FURNITURE Percent Reduction In Control Techno1ogy Coating Application Organic Emissions



## - Powder (spray or dip) Top or single coat 95-9ga Water-borne (electro- Prime or singlecoat deposition) Water-borne (spray, di

### p 

### Prime, top or single coat 60-9oa or fl wcoat) High!ersolids 

### (spray) Top or single coat 50-8oa 

### Carbon adsorption Prime, top or single coat (

### application and flashoff areas) Incineration Prime, top or single coat gob (ovens)

a~he base 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 inmetal furniture than fluidize bed because of itsabi! ity to coat the pieces with thinner films of coating Elec.trostatic sprayed powders can be applied at filmthicknesses of2 m 1 s
or greater while f1:~iclisedbed powders are limited to 

### 6 mils or greater After application, the powder particles are melted and cured inthe oven to form a continuous ,sol idfilm. 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 inemissions 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 attractedtothe grounded metal furniture piece. The powder can wrap around the edges ofconiplicated forms and isself-leveling
on flat pieces. Film thickness may be controlled by voltaqe,and a thickness of 

### 3 to 

### 4 mils can easily be achieved. Filmthicknesses of

### 2 to 

### 3 mils can be achl~eved with special attention and a very close control. Thinner films, however, have been achieved only inthe laboratories and not on production 1ines.5 Powder spray roating requires a booth as does spray coating with conventional coatinqs

## . However, ventilation requirements are greatly reduced from those of solventborne spray booths mainly because the booths are not occupied. This obviates the need to heat oraircondition air going into the

### spray booth and saves energy. Most powder overspray may be reclaimedand 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 utilization. To change colors ina 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%edto the spray booth. Some have also purchased multiple mobi1 e spray booths with associated recovery equipment. Powder coating may also he appliedby dipping metal pieces into a fluidized bed. In the metal furniture industry, dipping has the disadvantage ofapplying powder only inthick films (at least 

### 6 mils). The metal furniture piece is preheated to the melting point of the powder, dipped into the bed and heldthere until the desired 

### film thickness is achieved. Inelectrostatic 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 1imited to simp1e 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 conventional coat ings and no flashoff zones are required, smaller ovens may be installed. Further technical details on the use of powder coating's may be 

### 7 found inVulume 

### I, Sections 3.3.3 and 3.3.5. 2.2 ELECTRODEPOSITION Electrodeposition (EDP) is being used at several facilities tocoat 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. Electrodeposition

### 11 provides increased corrosion protection and applies thin coatings more uniformly and at a greater transfer efficiency than any other application system. A1though electrodepositionwas previously 1

### imi ted toone totwo colors, a new installation 

### will be applying four different colors. 

### EDP coat-ings are appliedfrom an aqueous bath which contains about 10--15volume percent solids and 2-4 volume percent organic solvents. 

### A direct current is

### applied inthe 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 bathwith a coating containing about 90 volume 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 isoften 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 inthe 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 solvent-borne coatings, they can often be substituted for existing solventborne coatings without requiring major changes to existing coating equipment. There may be however, sane necessary alterations in equipment orthe coating 1

in12to protect the equipment from corrosion,to lengthen the flashoff area and sometimes to control the humidity inthe application and flashoff areas. Several metal coating facilities 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 

### filmproperties. A 

### reduction of60-90 percent in VOC 

### emissions may be obt,ained by conversion to a water-borne coating. Water-borne coatings may be sprayed electrostaticallyon small coating 1ines if the entire coating system is electrically isolated. On larger lines, however, where the paint storage areas are hundreds oreven thousands of feet away from the application areas, electric isolation ofthe entire system becomes difficult and sometimes financially impractical.13314 

## co1or changes often require on1y 

### that the app'lication system be flushed out with water. Coating with water-borne coatings may require more attention tothe coating process since temperature, humidity, gun-to-metal distance and flashoff time may change the looks and performance ofthe coating. Conventional air and airless spray techniques may also be used to apply water-borne coatings. Fur1:her technical details on the use ofwater-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 ofsolids. Higher solids 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 a1though manual and conventional spraying techniques
can a1so 

### 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 inorder to pump and atomize these coatings due to their higher viscosities. Transfer efficiencies of higher solids coatings are often better than those of conventional coatings, particularlywhen sprayed electrostatically


## .18 

### As the solids content is increased ina coating, less solvent is released for each dry mil 

### of coating. This may permit some reduction in airflow to the booth (ifthe airflow was originaiiy determined by the 

### threshold limit

### of organic sol vents) resulting inan 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 ofhigh solids coatings may be 20 

### found inVolume I, Section 3.3.2.


### 2.5 CARBON ADSORPT I ON As discussed in Chapter 1, from 50 

### to80 percent ofthe volatile organic compounds from metal furniture coatings are emitted 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 device

# . Carbon adsorption isconsidered a viable control option for the application and flashoff areas because exhaust gases are at ambient temperature and contain only small amounts of particulatematter that could contaminate the carbon bed. Althouqh there are no known installations ofa carbon 2

### 1 adsorption system ina metal furniture plant, it 

### istechnically 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 furnituremanufactured. 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 faci1 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 inmetal 24 

### furniture faci1ities. 

### Incinerators are more efficient than carbon adsorbers for reducing VOC emissions from metal furniture ovens. Althouqh some energy is.requiredto 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 inthe 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 inthe 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 inthe incinerator. 

### A higher 

### VOC concentration 

### will provide a greater fraction ofthe total fuel requirement. Thus, increasing the VOC level not only reduces the size of the required incinerator and itscapita1 and fixed operating cost, but also the fuel requirements. The degree of difficiilty in retrofitting incinerators

### to (existingmetal furniture facilities will vary depending on the age of the equipment and facility, 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 3.2.2.2

### 6

### REFERENCES LeBras, Louis 

### R., Technical Division Director, PPG Industries, Pittsburgh, Pa. Letter to Vera Gallagher incomment 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 FinishingWorld. Pages 20-22 and 

### 50-52. Second quarter, 1975. Besselsen, John, Painting With Powder. Technical Paper presented at the Association for Finishing Processes ofSociety of Manufacturing Engineers in Cincinnati, Ohio, 1975. (FC 76-431). LeBras, Op. Cit. 

### Dornbos, David L. Sr., 

### Steelcase Incorporated, Grand Rapids, Michigan. Letter to Vera Gallagher incomment 

### of this document. Letter dated August 31, 1977. OAQPSGuide1ines "Control ofVolatile 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 incomment to draft ofthis 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., Application Equipment for High-Solids and Plural Component Coatings. High-Solids Coatings, Volume 

### I, No. 2, April 1976. LeBras, Op. Cit 

### Lunde, Dona1

### d I,,Aqueous and High-Solids 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 ofa 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 Corporation, Warren, Michigan. Letter toJames 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 atmetal 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 solvent coating materials: 1. Higher solids (70%or above) 2. Waterborne 3. 

### Powder A1ternative II-dxhaust Gas Treatment Installation of hydrocarbon control equipment: 1


## . Carbon adsorption for application exhausts 2. 

### Thermal incineration for oven exhaustsDetailed 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 (annualized cost (credit) per metric unit weight of VOC controlled) for the a1ternative 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 inthis 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. Ingeneral

## , no attempt has been made to consider detailed design characteristics for the model lines in terms of process equipment requirements, line speed, etc. However, itwas 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 a1ternatives considered. It isemphasized that model coating lines used inthis analysis are particularly simple inthat a one color single coat isapplied tometal 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 inthe discussion of the bases for model 1ine cost estimates. Finally, although control costestimates 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.



### -Cost Estimates 

### 3.1.4 Bases for Capital

----- 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 ingoing to low-solvent coatings. Th

### isshould 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 1ine conversions.

### 7'9'10 A11 capital costs are intended to r e f 1 e c t second quarter 

### 1977 do1lars. 3.1

### .5 Bases for
--. Annualized Cost Estimates. Annualized cost estimates for the control alternatives considered
are developed to reflect annual charges for capital required to purchase and instal1 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 "capitalrecovery 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 ingoing from the conventional solvent coating to the I~JW solvent coatlng. As evidenced later inthis chapter*, some conversions are projected to result innet annualized savings wbile others appear to result in increased annual costs. The bases for these ~1rojec.ted incremental costs or savings were provided inReferences 1 and 2. Again it isemphasized that these model coating line analyses are provided as a means of comparing the relative costs of a1ternative control measures. The area of estimating incremental annual costs (savinqs) for alternative coatings isone inwhich 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 incoating thickness requirements, transfer efficiencies, raw material costs and solids content all influence this cost element. Assumptions used inthis analysis
are provided later inTable 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 inTable 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 indeveloping the control cost estimatesTable 3-1. COST FACTORS USED 

### IN COMPUTING ANNUALIZED COSTS
I. Direct Operating Costs A. Materials (As purchased): 

## *

- A1kyd conventional 

### solvent coating (40%solids) $2.00/1 

### iter ($8/gal) 

## *

- Polyester high solids coating (70%solids) $3.70/1 

### iter ($14/gal) 

## *

- Alkyd Waterborne coating (402 solids) $2.40/1 iter ($9/gal)



### - Epoxy powder coating $3.30/kg ($1.5O/lb) 

## *

- Electrodeposition waterborne (60%solids) $2.90/1 

### iter ($11 /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 

### Ib)



## - Boiler feed water $0.13/thousand liters ($0.50/thousand gal) 3. Direct Labor 

### 4. Maintenance Labor



## - Process modifications $1 O/man- hour



## - Add-on systems 0.02 x Capital Cost 

### 5. Maintenance Materials 0.02 x Capital Cost 

### 6. Waste Disposal



## - El ectrodeposition $0.008/1 

### iter coating ($0.03/gal)



### - All others $O.O3/l iter coating ($O.ll/gal) Annualized Capital Charges 1. Depreciation and interest 0.1468 

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

## * By volumeprovided inTables 3-3 and 3-4 are summarized inTable 

### 3-2. Additional information regarding the expected range for many of these parameters is included inChapters 

### Two and Three of this document. 

### 3.2.1 Electrostatic Spray Line Capital and annualized costs for control a1ternatives applicable to electrostatic spray coating lines are presented inTable 3-3. Capital costs for converting lines to higher solids coatings (70%and above) or towaterborne coatings are related to application 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 inChapter 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 installdtion at powder application and recovery systems. Since models considered are one color 1 ines, only one recovery system is included incapital cost estimates. Mu1ti-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 lineconversion costs.Tab1e 

### 3-2. TECHNICAL PARAMETERS FOR MODEL COATING LINES
Electrostatic Spray Li tie

Number of Booths Automatic Manual Dry Coating Thickness, ~m (mils) Conventional solvert Hligher solids Waterborne Powder Tranisfer efficiencies Exhaust gas volumes

### ,

# N m

### 3Isec (scfm)

Dip Line Dry Colating Thickness, 11m (mi

### 1s) Conventional solvent klaterborne Electrodeposition Transfer Efficiencies Same as Table 

### 2 

## - Chapter 

### 2 Exhaust gas volumes,

- ~m"/sec. (scfm)

Clip TankTable 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~entalCosts 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 parbanAdsorpt~on Oven 

## I (Spray Booth) 

# 1

# Ol:"~inerator Carbon Adsorption

# 1 with Primary I Solvent at with Primarv Solvent at 1 and

-+ -- HeatRecovery

_ 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 ($00O/yrj Solvent Emissions Controlled (Mglyr) Percent Emission Reduction (Total) Cost per Mg of VOC controlled ($/Mg)

a~ne color 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~eferences1,2. g~gmegagram = 1 metric ton = h~eferences1, 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 3aseline 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 215b 5C 208~ Direct Operating Costs (Savings)

($000/yr) Capital Charges ($OOO/yr) Net Annualized Cost (credit) ($000/yr Solvent Emissions Control1ed (~~/?r !g Per~ent Emission Reduction Cost (credit) per Mg of VOC

controlled ($1~9) (uip lank) (DipTank) W (Oven) (Oven) ,Lo Alternative I1

### - Exhaust Gas Treatment Thermal Incinerator Carbon~dsorption Oven ~ermalIncinerator 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 Annualized Cost ($000/yr) Solvent Emissions Controlled (Mglyr) Percent Emission Reduction (Total) Cost per Mg of VOC Controlled ($/Mg)



### - 

# i

a~ne 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 solids coatings due mainly 

### t.o the estimated lower applied filmcost when compared to conventional solvent coatings

# . As noted inTable 

### 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 inTable 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. Ingeneral, 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 annualized costs for the control a1ternatives considered for existing dip 

### 1ines are summarized inTable 

### 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 usedand some corrosion protection is required. On the other hand, dip lines converting to the waterborne electrocoat will require significant investments when instal1 ing the electrodeposition application 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 electrodeposition. Increased annualized costs for controlling dip coating lines by conversion towaterborne are primarily a result of higher material costs for the waterborne coating. For electrodeposition, lower applied film costs for the electrocoat material he1p over-ride increased electrical costs associated with the electrodeposition system. 

## '* A1though incremental direct operating cost increases for the electrodeposition system appear to be minimal in Tab1e 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 inTable 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 inTable 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 inthe 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 Control1 ed 278,000 rn2/yr. 4,500,000 m2/yr. Reduction in

### VOC 

### A. Conversion to Higher Solids Coating (158)* (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 Control1 ed
---I N 650,000 m2/yr. 2,100,000 

### rn21yr % Reduction in

### VOC


## - G. Conversion 

### to Waterborne 

### H - Conversion to Electrodeposition 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 (Base1ine=25% Solids 

### Conventional Coating)



# - Electrostatic Spray

--.--- 

### Dip NOTE: 

### Refer to Table 3-5 for code to letters

Mi11

### ion Square Meters/Yearhigher solids conversions. Infact, at higher production rates the results appear to indicate that 

### it ismore cost-effective to incinerate oven exhausts and treat booth exhausts by carbon adsorption than convert to powder coatings. For dip coating lines, converting toan 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 inVOC by converting to electrodeposition, the cost per megagram of VOC controlled is higher than waterborne conversion over the range ofsizes 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 tovary 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 solids coatings (70%or greater) or a waterborne coating appears to be the most cost effective control a1ternative. The latter a1ternative, however, may have 

### 1imi ted application due to the technical and cost implications associated with some line configurations. For clip coating lines conversion towaterborne, where applicable, seems the most cost-effective alternative. Controlling 

### VOC emissions by incineration and carbon adsorption appears to be the least cost-effective alternative forthe m~odel1

### ines considered. Finally, it isstressed that the resu

### 1ts of this analysis are intended only to serve as guidance inassessing the relativecosts of a1ternati ve control schemes. Individual requirements and specifications of a particular coating 

### 1 

### ine may requireanalysis 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 Bi11 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 Gallagher, 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, I11inois, December 8, 

### 1977. H-igh Solids Coatings Volume 2, 

### No. 2, Technology Marketing Corporation Stamford, Conn. 

### , Apri1 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 isconverted to apply powder coatings besides the substantial reduction inemissions. There are almst none of the solidor liquidwaste disposal costs
or problems that are often encountered when using solvent-borne coatings. Powders do not, require the purchase ofadditional solvents to control viscosity orto 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. (A1though the lower explosive 

### limitis higher than for solvent, the reduction inairvolumes 

### is possible mostly because the spray booth is not occupied.) By 

### using an efficient particulate collector, the spray booth airmay 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 inenergy 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 orwelds inthe 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. A11 appl

### ication equipment, spray booths and associated equipment (and often ovens) used for llquidsyste~~is must 

### be 'replaced. This will then limit

### the coating flexibi1ity

### ofthe 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 linebasis. 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 ifthe powders are not reclaimed intheir respective colors resulting ina 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 a1ternative. No one can yet provide the so-called metal1ic coatings inponder, Color matching during manufacturing ofpowder is difficult. Powder fi

### lms have appearance 1imitations. 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, inaddition to reduced VOC emissions

## ,accrue 

### from converting to electrodeposition.

### The major one is good qua1itycontrol as a consequence of the fully automated process. It provides a very high transfer efficiency. It also provides excellent mating coverage and corrosion protection because the paint particles penetrate into the smallest recesses. (However, because the coverage is 

### so uniform, electrodeposition does not mask imperfections inthe 

### substrate as well as other application techniques). The low solvent content permits lower vent reduced energy consumption. The dry off oven that normally follows the longer required a1tho~gh an additional rinsewith ilation rates resulting in

pretreatment step is no deionized water isessential. Conversion to electrodeposition may also result in lower insurance costs because of reduced f

### ire and toxicity hazards. There are severa

### 1 disadvantages to the electrodepos

### i tion process. One is that it requires a unique type ofapplication equipment. 

### As
a result, electrodeposition can 

### be capital intensive when used on small scale production 

### 1ines. 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 clectrodeposition 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, refrigeration (to overcome the heat generated by the el ectrical process), to circulate the bath, and purification of the bath. If

### a spray operation is

### rep1 aced by solid and 1 elimination electrodeposition, some credit may be 

### a1lowed for decreased iquidwastes 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 stillwet since they are not soluble intheir carriers when they become dry making cleanup with organic solvents necessary. 

### A potential disadvantage of water-borne coatings isthat energy consumption may increase because some water-borne coatings must be flashed off under controlled humidity, and the ovens may have tobe 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 curing 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 a1low a uniform evaporation rate of water during high and 5 

### low humidity conditions. Disposal of

### solidor liquidwaste may be difficult. In dip or flow coating processes, an additional rinse may be required to avoi d contaminaticln of the coating bath.Overspray froni water-borne does not harden as rapidly making sludge hand1ing more difficult. Proper pretreatment iscritical to prevent flash rusting of metal furniture.
4.4 HIGHER SOLIDS COATINGS Higher solids coatings can be appliedwith existing spray equipment. These coatings are presently limited to about 65 volume percent solids, a1though research isbeing done; both on high solids (65-80 percent) coatings and on improved application equipment. Conversion to higher solids coatings can reduce energy requirements. 

### Airflow inthe spray booth can be reduced because less organic solvent isapplied for each dry mil of coating. The oven energy requirements may also be reduced. Solidand 1iquidwaste may decrease since less coating isapplied per dry 

### mil. However, the tackiness of some high-solids coatings may make cleanup more difficult.6 Although the sol vent content is reduced, thus reducing the level oftoxicity, there isa potential health hazard associatedwith isocyanates used in some high-solid, two-component systerns.


### 4.5 CARBON ADSORPTION There are no metal coating facilities known to use carbon adsorbers to redwe VOC from application and flashoff areas. This technology, however, is technically feasible for such applications and iswell documented. 

### A potentia1 disadvantage isthat itwill increase the requirements for electrical and fuel energy. The amount will depend or1 application, size ofadsorber, and concentration of the organics entering the carbon bed. Any decrease in airflow and accompanying increase inVOC concentration from the coating application and flashoff areas 

### will reduce the energy demands.

### 15

### gercent LELI. 

### "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 'ri'ti 

### "riiiagher 

### :n cornmerit of this document. Letter ddted 

### Septenier

. , 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~l

### and Dip," Prod~cts Finishing. Pages 73-76. February 13'7. 6. 

### "Questicn 

### Cowe:


## . ' 

### riigh-Sol ids Coatings, Volume I, No. 3. July 1976. i'. 

### Curnbustlor E +i31nr-~-~ng Ai 

### r Prehedter Wellsville, New York, Report of Fwl Requirement:, -a~ital Cost and Operating Expenses for Catalytic ~1nd 

### Pherrw?; 7ftewurn~r.s. EFA 

### Contr-dct 

### Report No. EPA-450/3-76-031 

# . Septernb~y

## :976

### 5.0 MONITORING TECHNIQUESAND 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 inthe preface, there is no universal VOC 

### emission control technique applicable for the industry as a 

### whole because ofthe variety of metal furniture products manufactured. Hiowever, metal furniture faci1

### ities have certain similaritieswhich permits grouping them for use ofcertain 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 i1s isnot 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, ifa facility must color match or change colors frequently, water-borne or higher-sol

### ids coatings would be the best choice. The recomnended emission 1 imit(3.O lbs of organic solvent per gallon of coating, less water), as stated inthe Preface,is based
on the application of water-borne or higher solids coatings. Sample calculations to verify compliance with this emission limitare shown inAppendix A. Previous control regulations for VOC have included limitationson the reactive organic solvent 

### orhave stipulated that a minimal reduction be achieved through add-on control equipment. While either approach isacceptable, maximum solvent content isa more pra~tical basis for those surface coating operations where use of low-solvent coatings 

### will generally be the compliance technique. 5-1For metal furnlture indu%tries, it .Is recommended that emission limitations be expressed interms of organic solvent content since these values can be determined with re1ati vely simple analytical techniques. Limitations in 

### VOC may be expressed in terms ofmass or volume and may be based on the (entirecoating (including organic solvent) oronly on paint solids. Inthis guideline, limitations are expressed as the allowable
mass of organic solvent per unit volume of coating (kgs per literof coating
or lbs per gallon ofcoating) as 

### it is delivered to the coating applicator. Wa'ter inthe coating issubtracted. 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 interms of mass oforganic solvent per unit volume of paint solids (kgs per literof solids or lbs per gallon ofsolids), the disparity disappears


## . The relationship is 1 inear and more readily understood e.g., a coating cont(3ining 2 lbs oforganic 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 ofVolatile Organic Emissions -,'ram Existing Stationary Sources

- Volume 

### I1: Surface Coating ofCans, Coils, Paper, Fabrics, Automobiles and 

### Light: Duty Trucks" presents 

### ASTM methods for determination of the pounds oforganic solvents per galIon 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 paintsolids 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 inorganic solvent. 

### Itdoes 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 filmthickness, the decrease in

### filmthickness can still result ina 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 inVOC content can be included inthe overall system to provide the equivalent reduction inemissions, Inthose few far: litieswhere add-on control equipment isa more likely optjon, itmay be more appropriate to state emission limits interms 0

### f cont;rol efficiency across the incinerator, adsorber, etc. Where 

### lim

### itat ionsare expressed only interms 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 ofcoatings during any given period and to determine the amount oforganic solvent directed tothe control device. Chapter 5 of "Control of Volatile Organic Emissions from Existiny Stati0nar.y Sources


### - Volume I: Control Methods for Surface Coating Operations" 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 requirethat the coating lines be equipped with an approved capture device toassure effective control. The capture system 

### will 1 ikelv have to be custom designed toaccommodate the plant-toplant variables which affect performance. When reviewing the design of such a syste~n,however, the air pollution control official must consider requirements 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 possibilitythat some ofthe monomer may evaporate. 

### A1so, 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 expensiveand sophisticated analytical techniques. The more practical means of quantifying the contribution of the polymerization reaction tothe overall emission ~~roblem would be by contacting the manufacturer of the coating. Certainly, his know1edge o f the fundamental chemical mechanisms involved would allow calculation ofan emission rate based
on the chemical reaction. This emission will occur during the cure (ifat all) which is usually temperature initi(3tedby 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 indetermining 

### 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 limitof 

### 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 isto preclude compliance through dilutionwith 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 isto cover a substrate with a filmthat provides both corrosion resistance to the substrate 

### and esthetic appeal. Therefore, the rational basis for specifying an a1lowable VOC emission limitwould be inunits 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 1imitations were developed inkilograms (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 oforganic solvent or (2) ef = lvol ume fraction organic solvent)(average organic solvent density) 

### 1 

## - volume' fraction ofwater

### 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<anthe recommended 

### limitof 0.36 kg/liter (3.0 lt:~s/gal),this coating 

### is incompliance.
CASE 2: 

### Determine the emission factor for a water-borne coating containing 

### 75 percent solvent. Since 80 percent of the solvent iswater, 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 if

### suitable add-on control equipment is installed. However, this method of determining the equival vent emission 1imi t 

### factor 

### isnot as straiqhtforward as the previous two cases and must also consider the volume of solids inthe coating.

&Tis'density i

### s considered typical and isequal 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 inthis 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 solids 

### 1iter solids gal 

### , solids 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 solvent per 1iterof solids applied (2..64

# - 0.6). 

### This will require a control system that isat 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 ofthe VOC emitted by the coating iscaptured 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

### ication and flashoff areas and ovens, the agency 

### will riornial

### lycertify an acceptable capture system based on good engineering practice.

### 1

### APPE:NDIX A 

### REFERENCE 1. 

### Young, Dexter E. 

## ,Environmental Protection 

### Agency, memorandum concerning requirements for ventilation 

### of spray booths and 

### ovens. Dated March 10, 1977.--- - - --

-- - -- -- 

# I TECHNICAL REPORTDATA



### -- (PlrasereadIarYuctzons on therer,ersebelore completing/ 

## ' RE@%&50/2-77 -032 1 7 3 RECIPIENT'S ACCESSIONNO. I 

# I---

- 

### I

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

### ControlofVolatileOrgar~icEmissionsfromExisting December1977 6.PERFORM~NGORGAN~ZAT~ONCODE Stationary Sources


### - Volume 

### II

### 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 Carolina 2771

### 1



### _ ___________I--- 13. TYPE OF REPORTAND PERIOD COVERED 

# WG AGENCY 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 limitwhich represents Reasonablv Available Control Technoloqy (RACT), methods by which RACT can be achieved, and monitoring and enforcement aspects.



## - 17. KEY WORDS AND DOCUMENTANALYSIS

- - - --- - _ - - -- - ---- a DESCRIPTORS ~.IOENTIFIERS/OPENENDED TERMS c COSATI F~eld/Group 

### Air Pollution 

### Air Pol1 ution Control 

### VOC Emission Limits Stationary Sources Metal Furniture Industry Organic Vapors Regulatory Guidance

18. DISTRIBUTION STATEMENT (ThisReport) 21. NO.OF PAGES 

### 6 3 

# t

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