## PAINTING BASICS AND EMISSION CALCULATION S

FOR TCEQ AIR QUALITY PERMIT APPLICATIONS

NOVEMBER 5 , 2012



# TEXAS COMMISSION ON

ENVIRONMENTAL QUALITY

Protecting Texas by Reducing

And

Preventing Pollution

Presented by:

Mike Coldiron, P .E.

Texas Commission on Environmental Quality

Austin, Texas1

INTRODUCTION

Surface coated products are all around, and coatings are applied to many types of industrial

equipment and consumer products to provide decorative and protective finishes as well as

functional uses such as adhesives. The application of these finishes, while improving product

performance or extending product life, releases significant emissions of solvents and solids into

the environment. As such, the EPA, state, and local authori ties have promulgated regulations

that limit coating solvent content, emission rates, solvent, and solid species limits to reduce the

formation of ground level ozone and to protect public health from unhealthy levels of exposure

to solids and solvents. In addition to the state and federal industry

- wide rules, all facilities in

Texas that emit air contaminants into the air of the State of Texas must obtain a preconstruction

permit authorization before construction of the facility is begun, as required by Ti tle 30 Texas

Administrative Code (30 TAC) §116.110.

There are a number of methods to demonstrate compliance with the emission limits in

regulations or to estimate emissions for preconstruction authorizations such as AP

- 42 emission

factors, stack sampling, coating solvent testing, or the use of continuous emission monitors.

Emission factors lack accuracy and even applicability to a specific type of process or product

type. Stack sampling and continuous monitors are expensive and lack the ability to demonst rate

compliance with coating solvent content limits. Monitors also tell the facility about a problem or

potential violation only after it has occurred. Coating solvent content testing may be used both

before and after the application of the coating, but this can be expensive and inconvenient.

Emission calculations effectively deal with many of these problems and reduce compliance

demonstration costs, prevent violations, allow the facility to set appropriate emission limits

during permitting, and provide important cost and process information to facility management.

However, the accuracy of the calculations is dependent on the quality of the data used in the

calculations, and the level of effort required to produce the results is dependent on the how well

the data is organized. The purpose of this paper is to provide environmental professionals with2

the necessary background to collect usable data, organize the data, and use the data to

successfully complete emission calculations for a number of types of e mission standards and

limits.

REASONS TO CALCULATE EMISSIONS FROM SURFACE COATING SOURCES

Traditionally, calculations were carried out after the fact in response to regulatory requirements

and were looked upon as a burden to the facility. However, emissi on calculations provide both

predictive and retrospective evaluations of surface coating facility operations from an

environmental and business perspective. Rather than being viewed by management as an

expense, emission calculations can provide opportunit ies for process improvement and

reductions in operating costs.

The retrospective use of emission calculations is primarily for demonstration of compliance with

regulatory requirements such as the following:

 Federal New Source Performance Standards (NSPS) u nder Title 40 Code of Federal

Regulations, Part 60 (40 CFR 60);

 Federal National Emission Standards for Hazardous Air Pollutants (NESHAPs) under

40 CFR 63;

 State Reasonably Available Control Technology (RACT) requirements;

 State and federal construction pe rmits; and

 State and federal operating permits under 40 CFR 70;

Retrospective uses also include the determination of emissions for historical purposes such as the

following:

 Emission Inventories;

 Calculation of Emission Fees; and3

 The quantity of emissio ns released during emissions events (formerly known as

‘upsets’).

Prospective uses allow the facility to ensure compliance before the fact in areas such as the

following:

 Air quality construction permit applications;

 Determination of applicability of Stat e and federal permit programs;

 Evaluation of new processes and products to determine if they will be compliant with

State and federal rules before introduction;

 Monitor process performance and reduce production costs through improvements in

transfer effic iency and increasing coatings solids content;

 Determination of optimal operating points for volatile organic compound (VOC) and

particulate matter (PM) emission controls;

 Production scheduling to maintain compliance with RACT, NSPS, and NESHAP

rules that a llow for averaging to comply with the standard;

Well

- organized and complete emission calculations in both modes will result in greater

confidence in facility management of the ability of the facility to meet applicable requirements.

DEFINITIONS

Emission calculations are more easily understood if the exact wording of regulatory definitions

and their limitations are understood. What the definitions do not say is as important as what they

do say as well as how they are related to each other.

Coating

– A m aterial applied onto or impregnated into a substrate for protective,

decorative or functional purposes. Such materials include, but are not limited to, paints,

varnishes sealants, adhesives, thinners, diluents, inks, maskants, and temporary protective

coa tings.4

Coating application system

– Devices or equipment designed for the purpose of

applying a coating material to a surface. The devices may include, but are not limited to,

brushes, sprayers, flow coaters, dip tanks, rollers, knife coaters, and extrusi on coaters.

Coating line

– An operation consisting of a series of one or more coating application

systems and including associated flashoff area(s), drying area(s), and oven(s) wherein a

surface coating is applied, dried, or cured.

Coating solids (or solid s)

– The part of the coating that remains after the coating is dried

or cured.

Capture efficiency

– The amount of VOC collected by a capture system that is expressed

as a percentage derived from the weight per unit time of VOC entering a capture system

and delivered to a control device divided by the weight per unit time of total VOC

generated by a source of VOC.

Exempt solvent

– Those carbon compounds or mixtures of carbon compounds that have

been excluded from the definition of volatile organic compound.

Hazardous air pollutant

– Means any air pollutant listed in or pursuant to section 112(b)

of the [Federal Clean Air] Act. Hazardous air pollutants (HAPs) are as follows:

CAS No. Pollutant CAS No. Pollutant

75070 Acetaldehyde 79118 Chloroacetic acid

6035 5 Acetamide 532274 2

- Chloroacetophenone

75058 Acetonitrile 108907 Chlorobenzene

98862 Acetophenone 510156 Chlorobenzilate

53963 2

- Acetylaminofluorene 67663 Chloroform

107028 Acrolein 107302 Chloromethyl methyl ether

79061 Acrylamide 126998 Chloropre ne

79107 Acrylic acid 1319773 Cresols/Cresylic acid (isomers and mixture)

107131 Acrylonitrile 95487 o

- Cresol

107051 Allyl chloride 108394 m

- Cresol5

CAS No. Pollutant CAS No. Pollutant

92671 4

- Aminobiphenyl 106445 p

- Cresol

62533 Aniline 98828 Cumene

90040 o

- Anisidine 94757 2,4

- D (2,4

- Dichlorophenoxyacetic Acid)

(including salts and esters)

1332214 Asbestos 3547044 DDE (1,1

- dichloro

- 2,2

- bis(p

- chlorophenyl)

ethylene)

71432 Benzene (including benzene from gasoline) 334883 Diazomethane

92875 Benzidine 132649 Dibenzofuran

98077 Benzot richloride 96128 1,2

- Dibromo

- 3

- chloropropane

100447 Benzyl chloride 84742 Dibutylphthalate

92524 Biphenyl 106467 1,4

- Dichlorobenzene (p)

117817 Bis (2

- ethylhexyl) phthalate (DEHP) 91941 3,3

- Dichlorobenzidene

542881 Bis (chloromethyl) ether 111444 D ichloroethyl ether (Bis[2

- chloroethyl]ether)

75252 Bromoform 542756 1,3

- Dichloropropene

106990 1,3

- Butadiene 62737 Dichlorvos

156627 Calcium cyanamide 111422 Diethanolamine

133062 Captan 121697 N,N

- Diethyl aniline (N,N

- Dimethylaniline)

63252 Carbaryl 64675 Diethyl sulfate

75150 Carbon disulfide 119904 3,3

- Dimethoxybenzidine

56235 Carbon tetrachloride 60117 Dimethyl aminoazobenzene

463581 Carbonyl sulfide 119937 3,3'

- Dimethyl benzidine

120809 Catechol 79447 Dimethyl carbamoyl chloride

133904 Chlora mben 68122 Dimethyl formamide

57749 Chlordane 57147 1,1

- Dimethyl hydrazine

7782505 Chlorine 131113 Dimethyl phthalate

77781 Dimethyl sulfate 72435 Methoxychlor

534521 4,6

- Dinitro

- o

- ocresol (including salts) 74839 Methyl bromide (Bromomethane)

51285 2,4

- Dinitrophenol 74873 Methyl chloride (Chloromethane)

121142 2,4

- Dinitrotoluene 71556 Methyl chloroform (1,1,1

- Trichloroethane)

123911 1,4

- Dioxane (1,4

- Diethyleneoxide) 60344 Methyl hydrazine

122667 1,2

- Diphenylhydrazine 74884 Methyl iodide (Iodom ethane)

106898 Epichlorohydrin (1

- Chloro

- 2,3

-

epoxypropane) 108101 Methyl isobutyl ketone (Hexone)

106887 1,2

- Epoxybutane 624839 Methyl isocyanate

140885 Ethyl acrylate 80626 Methyl methacrylate

100414 Ethyl benzene 1634044 Methyl tert butyl ether

5 1796 Ethyl carbamate (Urethane) 101144 4,4

- Methylene bis (2

- chloroaniline)

75003 Ethyl chloride (Chloroethane) 75092 Methylene chloride (Dichloromethane)

106934 Ethylene dibromide (Dibromoethane) 101688 Methylene diphenyl diisocyanate (MDI)6

CAS No. Pollutant CAS No. Pollutant

107062 Et hylene dichloride (1,2

- Dichloroethane) 101779 4,4'

- Methylenedianiline

107211 Ethylene glycol 91203 Naphthalene

151564 Ethylene imine (Aziridine) 98953 Nitrobenzene

75218 Ethylene oxide 92933 4

- Nitrobiphenyl

96457 Ethylene thiourea 100027 4

- Nitroph enol

75343 Ethylidene dichloride (1,1

- Dichloroethane) 79469 2

- Nitropropane

50000 Formaldehyde 684935 N

- Nitroso

- N

- methylurea

76448 Heptachlor 62759 N

- Nitrosodimethylamine

118741 Hexachlorobenzene 59892 N

- Nitrosomorpholine

87683 Hexachlorobutadiene 56382 Parathion

77474 Hexachlorocyclopentadiene 82688 Pentachloronitrobenzene (Quintobenzene)

67721 Hexachloroethane 87865 Pentachlorophenol

822060 Hexamethylene

- 1,6

- diisocyanate 108952 Phenol

680319 Hexamethylphosphoramide 106503 p

- Phenylenediamine

110543 Hexane 75445 Phosgene

302012 Hydrazine 7803512 Phosphine

7647010 Hydrochloric acid 7723140 Phosphorus

7664393 Hydrogen fluoride (Hydrofluoric acid) 85449 Phthalic anhydride

7783064 Hydrogen sulfide 1336363 Polychlorinated biphenyls (Aroclors )

123319 Hydroquinone 1120714 1,3

- Propane sultone

78591 Isophorone 57578 beta

- Propiolactone

58899 Lindane (all isomers) 123386 Propionaldehyde

108316 Maleic anhydride 114261 Propoxur (Baygon)

67561 Methanol 78875 Propylene dichloride (1,2

- Dichlorop ropane)

75569 Propylene oxide 593602 Vinyl bromide

75558 1,2

- Propylenimine (2

- Methyl aziridine) 75014 Vinyl chloride

91225 Quinoline 75354 Vinylidene chloride (1,1

- Dichloroethylene)

106514 Quinone 1330207 Xylenes (isomers and mixture)

100425 Styrene 95476 o

- Xylenes

96093 Styrene oxide 108383 m

- Xylenes

1746016 2,3,7,8

- Tetrachlorodibenzo

- p

- dioxin 106423 p

- Xylenes

79345 1,1,2,2

- Tetrachloroethane Antimony Compounds Antimony Compounds

127184 Tetrachloroethylene (Perchloroethylene) Arsenic Compoun ds Arsenic Compounds (inorganic including arsine)

7550450 Titanium tetrachloride Beryllium Compounds Beryllium Compounds

108883 Toluene Cadmium Compounds Cadmium Compounds

95807 2,4

- Toluene diamine Chromium Compounds Chromium Compounds

584849 2,4

- Tol uene diisocyanate Cobalt Compounds Cobalt Compounds

95534 o

- Toluidine Coke Oven Emissions Coke Oven Emissions7

CAS No. Pollutant CAS No. Pollutant

8001352 Toxaphene (chlorinated camphene) Cyanide Compounds 1 Cyanide Compounds 1

120821 1,2,4

- Trichlorobenzene Glycol ethers 2 Glycol ethers 2

79005 1,1,2

- Trichloroethane Lead Compounds Lead Compounds

79016 Trichloroethylene Manganese Compounds Manganese Compounds

95954 2,4,5

- Trichlorophenol Mercury Compounds Mercury Compounds

88062 2,4,6

- Trichlorophenol Fine mineral fibers 3 Fine minera l fibers 3

121448 Triethylamine Nickel Compounds Nickel Compounds

1582098 Trifluralin Polycyclic Organic

Matter 4 Polycyclic Organic Matter 4

540841 2,2,4

- Trimethylpentane Radionuclides

(including radon) 5 Radionuclides (including radon) 5

108054 Viny l acetate Selenium Compounds Selenium Compounds

For all listings above which contain the word "compounds" and for glycol ethers, the following

applies: Unless otherwise specified, these listings are defined as including any unique chemical

substance t hat contains the named chemical (i.e., antimony, arsenic, etc.) as part of that

chemical's infrastructure.

1 X'CN where X = H' or any other group where a formal dissociation may occur. For example

KCN or Ca(CN)2

2: Glycol ethers include mono

- and di

- ethers of ethylene glycol, diethylene glycol, and

triethylene glycol R

- (OCH 2 CH 2 )

n - OR′.

Where:

n = 1, 2, or 3; R = alkyl C7 or less; or R = phenyl or alkyl substituted phenyl; R′= H or alkyl C7 or less; or OR′ consisting of carboxylic acid ester, sulfate, phospha te, nitrate, or sulfonate.

3 Includes mineral fiber emissions from facilities manufacturing or processing glass, rock, or

slag fibers (or other mineral derived fibers) of average diameter 1 micrometer or less.

4 Includes organic compounds with more than on e benzene ring, and which have a boiling point

greater than or equal to 100 o C.

5 A type of atom which spontaneously undergoes radioactive decay.

 The substance caprolactam (CAS number 105602) is deleted from the list of hazardous air

pollutants establis hed by 42 U.S.C. 7412(b)(1). [61 FR 30823, June 18, 1996]

 The substance methyl ethyl ketone (MEK, 2

- Butanone) (CAS Number 78933) is deleted from

the list of hazardous air pollutants established by 42 U.S.C. 7412(b)(1). [70 FR 75059,

December 19, 2005]8

 The substance ethylene glycol monobutyl ether (EGBE, 2

- Butoxyethanol) (CAS Number

111762) is deleted from the list of hazardous air pollutants established by 42 U.S.C.

7412(b)(1). [69 FR 69325, November 29, 2004]

Particulate matter

– Any material, except uncom bined water, that exists as a solid or

liquid in the atmosphere or in a gas stream at standard conditions.

Transfer efficiency

– The amount of coating solids deposited onto the surface or a part

of a product divided by the total amount of coating solids d elivered to the coating

application system.

Volatile organic compound

– any compound of carbon or mixture of carbon compounds

except the following:

CAS NO. AIR CONTAMINANT NAME

67

- 64

- 1 ACETONE

506

- 87

- 6 AMMONIUM CARBONATE

124

- 38

- 9 CARBON DIOXIDE

630

- 08

- 0 CARBON MONOXIDE

---- CARBONIC ACIDS

- U

75

- 68

- 3 1

- CHLORO

- 1,1

- DIFLUOROETHANE (HCFC

- 142b)

75

- 45

- 6 CHLORODIFLUOROMETHANE (HCFC

- 22)

593

- 70

- 4 CHLOROFLUOROMETHANE (HCFC

- 31)

1615

- 75

- 4 1

- CHLORO

- 1

- FLUOROETHANE (HCFC

- 151a)

593

- 70

- 4 CHL OROFLUOROMETHANE (HCFC

- 31)

76

- 15

- 3 CHLOROPENTAFLUOROETHANE (CFC

- 115)

2837

- 89

- 0 2

- CHLORO

- 1,1,1,2

- TETRAFLUOROETHANE (HCFC

- 124)

138495

- 42

- 8 1,1,1,2,3,4,4,5,5,5

- DECAFLUOROPENTANE (HFC 43

- 10mee)

75

- 71

- 8 DICHLORODIFLUOROMETHANE (CFC

- 12)

1717

- 00

- 6 1,1

- DICHLORO

- 1

- FLUOROETHANE (HCFC

- 141b)

507

- 55

- 1 1,3

- DICHLORO

- 1,1,2,2,3

- PENTAFLUOROPROPANE (HCFC

- 225cb)

422

- 56

- 0 3,3

- DICHLORO

- 1,1,1,2,2

- PENTAFLUOROPROPANE (HCFC

- 225ca)

76

- 14

- 2 1,2

- DICHLORO 1,1,2,2

- TETRAFLUOROETHANE (CFC

- 114)

35 4

- 23

- 4 1,2

- DICHLORO

- 1,1,2

- TRIFLUOROETHANE (HCFC

- 123a)

75

- 37

- 6 1,1

- DIFLUOROETHANE (HFC

- 152a)

75

- 10

- 5 DIFLUOROMETHANE (HFC

- 32)

163702

- 08

- 7 2

- (DIFLUOROMETHOXYMETHYL)

- 1,1,1,2,3,3,3

-

HEPTAFLUOROPROPANE ((CF 3 ) 2 CFCF 2 OCH 3 )

616

- 38

- 6 DIMETHYL CARBONATE9

CAS NO. AIR CONTAMINANT NAME

74

- 84

- 0 ETHANE

163702

- 06

- 5 2

- (ETHOXYDIFLUOROMETHYL)

- 1,1,1,2,3,3,3

- HEPTAFLUOROPROPANE

((CF 3 ) 2 CFCF 2 OC 2 H 5 )

297730

- 93

- 9 3

- ETHOXY

- 1,1,1,2,3,4,4,5,5,6,6,6

- DODECAFLUORO

- 2

-

(TRIFLUOROMETHYL) HEXANE

(HFE

- 7500, HFE

- s702 , T 7145, and L

- 15381)

163702

- 05

- 4 1

- ETHOXY

- 1,1,2,2,3,3,4,4,4

- NONAFLUOROBUTANE (HFE

- 7200)

353

- 36

- 6 ETHYLFLUORIDE (HFC

- 161)

375

- 03

- 1 1,1,1,2,2,3,3

- HEPTAFLUORO

- 3

- METHOXYPROPANE (HFE

- 7000)

431

- 89

- 0 1,1,1,2,3 ,3,3

- HEPTAFLUOROPROPANE (HFC

- 227ea)

431

- 63

- 0 1,1,1,2,3,3

- HEXAFLUOROPROPANE (HFC

- 236ea)

690

- 39

- 1 1,1,1,3,3,3

- HEXAFLUOROPROPANE (HFC

- 236fa)

---- METALLIC CARBIDES

- U

---- METALLIC CARBONATES

- U

74

- 82

- 8 METHANE

79

- 20

- 9 METHYL ACETATE

75

- 09

- 2 METHYL ENE CHLORIDE

107

- 31

- 3 METHYL FORMATE

163702

- 07

- 6 1,1,1,2,2,3,3,4,4

- NONAFLUORO

- 4

- METHOXYBUTANE (HFE

- 7100)

98

- 56

- 6 PARACHLOROBENZOTRIFLUORIDE (PCBTF)

406

- 58

- 6 1,1,1,3,3

- PENTAFLUOROBUTANE (HFC

- 365mfc)

354

- 33

- 6 PENTAFLUOROETHANE (HFC

- 125)

431

- 31

- 2 1,1,1,2,3

- PENTAFLUOROPROPANE (HFC

- 245eb)

460

- 73

- 1 1,1,1,3,3

- PENTAFLUOROPROPANE (HFC

- 245fa)

679

- 86

- 7 1,1,2,2,3

- PENTAFLUOROPROPANE (HFC

- 245ca)

24270

- 66

- 4 1,1,2,3,3

- PENTAFLUOROPROPANE (HFC

- 245ea)

127

- 18

- 4 PERCHLOROETHYLENE (TETRACHLOROETHYLENE)

---- PERFLUOROCARBON COMPOUNDS WHICH FALL INTO THESE

CLASSES:

(1) CYCLIC, BRANCHED, OR LINEAR, COMPLETELY FLUORINATED

ALKANES;

(2) CYCLIC, BRANCHED, OR LINEAR, COMPLETELY FLUORINATED

ETHERS WITH NO UNSATURATIONS;

(3) CYCLIC, BRANCH ED, OR LINEAR, COMPLETELY FLUORINATED

TERTIARY AMINES WITH NO UNSATURATIONS; AND

(4) SULFUR CONTAINING PERFLUOROCARBONS WITH NO

UNSATURATIONS AND WITH SULFUR BONDS ONLY TO CARBON

AND FLUORINE.

108

- 32

- 7 PROPYLENE CARBONATE

---- SILOXANES: CYCLIC, BRANCHED, OR LINEAR COMPLETELY10

CAS NO. AIR CONTAMINANT NAME

METHYLATED

540

- 88

- 5 TERTIARY

- BUTYL ACETATE (T

- BUTYL ACETATE)

811

- 97

- 2 1,1,1,2

- TETRAFLUOROETHANE (HFC

- 134a)

359

- 35

- 3 1,1,2,2

- TETRAFLUOROETHANE (HFC

- 134)

29118

- 24

- 9 TRANS

- 1,3,3,3, TETR AFLUROPROPENE

71

- 55

- 6 1,1,1

- TRICHLOROETHANE (METHYL CHLOROFORM)

75

- 69

- 4 TRICHLOROFLUOROMETHANE (CFC

- 11)

76

- 13

- 1 1,1,2

- TRICHLORO

- 1,2,2

- TRIFLUOROETHANE (CFC

- 113)

306

- 83

- 2 1,1,1

- TRIFLUORO

- 2,2

- DICHLOROETHANE (HCFC

- 123)

420

- 46

- 2 1,1,1

- TRIFLUOROETHANE (HFC

- 143a)

75

- 46

- 7 TRIFLUOROMETHANE (HFC

- 23)

All definitions are from References 1 through 4.

It should be noted that the EPA definition of VOC does not take into acco unt vapor pressure or

volatility of the compound. However, this makes a big difference in practice because coating

resins and plasticizers meet the definition of VOC, yet they do not evaporate. The difference

between the regulatory definition and what oc curs under shop conditions for a coating can be

reconciled through the use of EPA Test Method 24 (40 CFR 60, Appendix A) which covers the

determination of coating VOC content, water content, density, volume solids, weight solids, and

1,1,1

- trichloroethane and dichloromethane content. The difference may also be resolved on a

species

- specific basis through the analysis of physical properties as follows:

 Vapor pressure at the maximum process temperature. Compounds with vapor

pressures less than 0. 0 1 mmHg can usually be assumed not to be emitted as stated in

the TCEQ Modeling and Effects Review Applicability (MERA) guidance document;

 Boiling point at atmospheric pressure. Compounds with boiling points above 400°F

can usually be assumed not to be emitted if no t heated significantly above room

temperature in the process; and

 Molecular weight of the compound. VOCs with molecular weights above 200 are

usually assumed not to be emitted if not heated significantly above room temperature

in the process.11

It is also i mportant to recognize that most common coating solvents and solids are also HAPs.

However, not all VOCs are HAPs, with mineral spirits being one of the more notable differences.

This provides coating manufacturers an important amount of latitude in the f ormulation of

coatings since many NESHAP rules regulate coating HAP content and not VOC content. This

allows for lower solids content while still meeting the HAP content limits.

COATING BASICS

Coatings are made up of two categories of constituents: solids and solvents. These categories

can be further subdivided as shown in Figure 1.

Solvents VOC HAPS

Solids

Solids

Figure 1. Coating Solid and Solvent Makeup

The types of ingredients within a coating may be obtained from Material Sa fety Data Sheets

(MSDS), technical data sheets, coating vendor technical staff, or from Test Method 24 (40 CFR

60, Appendix A). In order to complete a set of emission calculations, the use of more than one

data source is frequently required.

Resins

Pigments

Pigment Extenders

Fillers

Flatting Agents

Rheology Control

Biological Control

UV Inhibitors Water

Exempt Solvent

Thinners

Diluents

Reducers12

The coating m akeup provides only an inventory list of air contaminants and relative volumes to

evaluate but it does not describe the fate of the air contaminants as the parts to be coated pass

through the process. The fate of the solids and solvents depends on the con figuration of the

coating line. Three common scenarios are presented below:

DIP COATING

Solvents Solvents

Parts to Wet Dry

be coated Parts Parts

Figure 2. Dip Coating Emission Sources

SPRAY COA TING

– PARTS DRY IN BOOTH

Solvents

Over

- spray Solids

Part to Dry

be coated Parts

Over

- spray

Solids Fallout

Figure 3. Spray Coating Emission Sources

Dip Tank Parts Drying

PM Filter

Spray Booth13 SPRAY COATING

– PARTS ARE DRIED OUTSIDE THE

BOOTH OR IN AN OVEN

Solvents

Over

- spray Solids

Solvents Solvents

Parts to Wet Dry

be coated Parts on Conveyor Parts

Over

- spray

Solids Fallout

Figure 4. Coating Line Emission Sour ces

Emissions of Solids

The fate of solids is determined by the application and control methods used. In the first

example, application techniques with 100 percent transfer efficiency such as dipping, brushing,

rolling, and flow coating produce no PM emi ssions because all of the solids that leave the

applicator remain on the part. In the remaining examples, application techniques with a transfer

efficiency of less than 100 percent (e.g., spraying), the solids that leave the applicator end up in

four loca tions as follows:

 The part to coated;

 The interior of the booth due to overspray and overspray fall out within the booth;

 The overspray filters; and

 The portion not captured by the overspray filters exhausted to the atmosphere.

In order to determine the emissions of the solids to the atmosphere, the amount of solids in the

first three categories need to be quantified.

PM Fi lter

Spray Booth Drying Ovens14

The geometry of the part and the application equipment determine the transfer efficiency (TE),

which is a measure of the amount of spray ed coating that is applied to the part. TE may be

determined through several methods such as estimation from tables or charts, the volume of

coating applied to a part, or through the weighing of parts and the paint pots.

Estimation of TE from tables or c harts (see References 5 and 6) is the least accurate method and

is presented as Table 1.

Table 1. Transfer Efficiency as a Function of Application Equipment and Part Geometry

Application Equipment Flat Surface Table Leg

Surface Bird Cage

Surface Air Atom ized 50 15 10

Airless 75

- 80 10 10

HVLP 65 15 10

Electrostatic Disk 95 90

- 95 90

- 95

Electrostatic Airless 80 70 70

Electrostatic Air Atomized 75 65 65

A significant improvement in the estimation of TE can be achieved through the use of the

volume of coating applied to a part. This can be determined either through the use of wet or dry

film thickness, coating volume solids content, the surface area of the part, the number of parts

coated, and accurately weighing the application system (paint pots, hos es and gun) before and

after the coating is applied.15

Dry Film Thickness Method

Data Requirements

Surface Area of the Part 43 in 2

Dry Film Thickness 0.002 in

Coating Volume Solids Content 0.5

Coating Density 11.5 lb/gal

Amount of Coating Sprayed 2 .87 lb

Number of Parts Coated 150

Calculate Coating Consumption

2.87 lb gal = 0.25 gal

11.5 lb

Calculate Transfer Efficiency

TE = 43 in 2 0.002 in 150 parts gal 100 = 44.7 %

0.5 solids 231 in 3 0.25 gal

Wet Film Thickness Method

Da ta Requirements

Surface Area of the Part 43 in 2

Wet Film Thickness 0.004 in

Coating Density 11.5 lb/gal

Amount of Coating Sprayed 2.87 lb

Number of Parts Coated 15016

Calculate Coating Consumption

2.87 lb Gal = 0.25 gal

11.5 lb

Calculate Tran sfer Efficiency

TE = 43 in 2 0.004 in 150 parts gal 100 = 44 .7 %

231 in 3 0.25 gal

The best TE estimates can be provided by carefully conducted TE tests on a number of parts. TE

testing involves accurately weighing the parts and the applicatio n system (paint pots, hoses and

gun) before and after the coating is applied.

Part Weight Change Method

Data Requirements

Coating Solids Content 8.5 lb/gal

Coating Density 11.5 lb/gal

Amount of Coating Sprayed 2.87 lb

Number of Parts Coated 20

Weight Gai n Per Part 0.08 lb

Calculate Coating Solids Sprayed

8.5 lb Gal 2.87 lb = 2.12 lb solids sprayed

Gal 11.5 lb

Calculate Transfer Efficiency

0.08 lb solids 20 parts 100 = 75.4%

Part 2.12 lb solids17

For very large parts the method descri bed above can be modified through the use of sheets of

metal foil applied to the part that are weighed before and after the application of the coating.

The amount of overspray that falls out of the spray booth air stream before entering the

overspray filte r is determined by the application equipment and to a lesser extent the coating

viscosity. Application equipment with a greater proportion of larger droplets in the spray pattern

will have a greater portion of the overspray fall out within the booth. App lication equipment

with higher transfer efficiencies such as high volume low pressure (HVLP) or airless spray have

large numbers of larger droplets compared to air atomized spray equipment. Droplets with a

diameter of greater than 30 microns do not stay s uspended in the air stream for a significant

amount of time and will fall to the floor of the booth or impact the walls. Therefore, the fraction

of the paint overspray that will be emitted is the fraction of the droplet sizes that are smaller than

30 micr ons in diameter. Determination of the fraction of the droplets smaller than PM 10 and PM

2.5 is also necessary to determine the emission rates in these size ranges. The particle size

distribution will depend on the type of application equipment used since each type of equipment

has differing droplet size distributions. Particle size distribution data may be available from

application equipment vendors and from References 8 through 12. The following table may be

used to estimate PM, PM 10 , and PM 2.5 emissi on rates for both enclosed and outdoor coating

operations.

Table 2 Particle Size Distribution as a Function of Application Equipment

Application Equipment

Type Droplet Fraction Greater

than PM 30 Droplet Fraction Greater

than PM 10 Droplet Fraction Greater

than PM 2.5

Air Atomized 0.81 0.94 0.99

Airless 0.9856 0.9987 0.9999

HVLP 0.90 0.90 0.90

Overspray filters are used in nearly all spray booths to control PM emissions and the efficiency

of the filter system (dry filters or, in some older booths, water wash) is usually available from the18

filter system vendor. Overall PM control efficiencies (PM 30 and smaller) may be determined by

ASHRAE Method 52.1. Control efficiencies for PM 10 and PM 2.5 may be determined by

ASHRAE Method 52.2. Filter media evaluate d by this method will have a minimum efficiency

removal value (MERV) provided. To be assigned a specific MERV value, the filter media must

achieve a minimum composite average particle size removal efficiency minimum efficiency in

three particle size range s

. The size ranges are 0.3

- 1.0, 1.0

- 3.0, and 3.0 to 10.0 microns. If the

vendor provides a MERV for the filter media, the efficiencies for the various particle sizes may

be determined using the MERV chart.

Table 3 Composite Average Particle Size Rem oval Efficiency Requirements for a Sp ecific

MERV

Composite Average Particle Size Removal

Efficiency (%) in Size Range (μm)

- ANSI/ASHRAE Standard 52.2

- 2007 Contaminants Typically

Controlled Typical Applications MERV 0.3

– 1.0 1.0

– 3.0 3.0

– 10.0

1

— — <2 0 Particles >10.0 μm:

pollens, dust mites,

textile/carpet fibers Minimum filtration;

residential buildings 2

— — <20

3

— — <20

4

— — <20

5

— — 20

– 35 Particles 3

- 10.0 μm:

mold, spores, cement dust Most commercial and

better residential building s 6*

— — 35

– 50

7

— — 50

– 70

8

— — >70

9

— <50 >85 Particles 1.0

- 3.0 μm:

Legionella, lead dust, coal

dust, auto emmissons Superior residential and

better commercial

buildings 10

— 50

– 65 >85

11

— 65

– 80 >85

12

— >80 >90

13 <75 >90 >90 Par ticles 0.3

- 1.0 μm: all

bacteria, most tobacco

smoke, droplet nuclei,

most smoke Hospital inpatient and

general surgery; superior

commercial buildings 14 75

– 85 >90 >90

15 85

– 95 >90 >90

16 >95 >95 >95

IEST Standards

17 >99.97 on 0.30 μm parti cles, IEST Type A Particles <0.3 μm (viruses, Cleanrooms and19

18 >99.99 on 0.30 μm particles, IEST Type C radon progeny, carbon

dust) pharmaceutical

manufacturing 19 >99.999 on 0.30 μm particles, IEST Type D

20 >99.9999 on 0.10

– 0.20 μm particles, IE ST Type

F

* Mimimum requirement under ASHRAE standard 62.1 (Ventilation for Acceptable Indoor Air Quality)

Source: Adapted with permission from ANSI/ASHRAE Standard 52.2

- 2007: Method of Testing General Ventilation

Air

- Cleaning Devices for Removal Ef ficiency by Particle Size. Atlanta, GA: American Society of Heating,

Refrigerating, and Air

- Conditioning Engineeers, Inc. 2007 © American Society of Heating, Refrigerating and Air

Conditioning Engineers, Inc., www.ashrae.org

T he control efficiency of the system for the various particle size ranges will be determined by

limits on off

property concentrations of the PM species, applicable rules for ambien t PM, PM 10

and smaller and PM 2.5 and smaller concentrations, applicable state and federal rules and air

permit requirements

. As a result, e mission rates must be determined for three particle size

ranges ; PM, PM 10 and smaller and PM 2.5 and smaller.

Emissio ns of Solvents

All solvents are ultimately lost to the atmosphere. The difficult part is determining the emission

distribution or how much solvent is lost to the atmosphere at different steps in the process. The

emission distribution is dependent on the following:

 Transfer efficiency (TE);

 The solvent species and their relative amounts in the coating;

 The speed at which the parts are removed from the booth after spraying;

 The amount of time the parts are allowed to dry outside of the booth in a drying are a

or on a conveyor; and

 The use of drying ovens.

TE affects the distribution of solvent emissions because all of the solvents contained in the

overspray will be emitted from the spray booth based on the assumption of 100 percent capture20

efficiency. With h igher TE values, less overspray will occur in the booth to generate solvent

emissions.

The solvents used in the coating have the greatest effect on the distribution of solvent emissions.

Coatings such as lacquers that have “fast” solvents will have the ma jority of the solvent

evaporate or “flashoff” in the booth. Other coatings such as water based epoxies that have a

greater proportion of “slow” solvents will have a lesser portion of the solvents flashoff in the

booth and a greater proportion flashoff out side of the booth provided that the residence time in

the booth is the same.

As noted above, the residence time of the parts in the booth, in drying areas, flashoff tunnels, and

on conveyors will further determine the solvent emission distribution. The lo nger the parts

remain in any specific segment of a coating line, the greater the solvent emissions will be for that

segment. The fraction of the solvents emitted in any one segment of the coating line may be

estimated through the use of flashoff curves or through testing on the coating line or in a

laboratory where coating line conditions can be accurately duplicated.

Generic flashoff curves provide the least accurate estimate of solvent emission distributions and

an example of flashoff curves from Refer ence 5 is presented in Figure 5.21

Figure 5. Coating Flashoff Curves

The flashoff curves can be used to estimate the solvent emission distribution for the type of

coating in use based on the time that the parts remain in any segment of the coating line. F or

example, an epoxy coated part will have lost approximately 30 percent of the solvent upon

exiting the booth at 2 minutes after spraying. The same part will have lost an additional 9

percent of the solvent after 8 minutes on the conveyor (39% total loss

– 30% loss in the booth).

Increased accuracy in the solvent emission distribution can be achieved through the use of either

laboratory testing or testing on the coating line. For laboratory testing, coated parts are weighed

at specific time intervals tha t correspond to the change in line segments. The resulting weight

change at each time interval corresponds to the solvent loss. Similarly, testing on the actual22

coating line involves weighing parts at each process transition and recording the weight chan ge

to determine the solvent loss for the specific segment of the coating line.

If an oven is used in the process, the parts are usually dry upon exiting the oven. In the case of

dry parts, the solvent loss in the oven will equal the remaining amount of s olvent in the coating

on the part. For example, if 39 percent of the solvent is lost in the booth and on the conveyor, 61

percent of the solvent is lost in the oven (100%

- 39% lost in the booth and conveyor).

CLASSIFICATION OF CALCULATIONS AND SUMMARY OF REQUIRED DATA

AND DATA SOURCES

Emission calculations for surface coating fall into two broad categories as follows:

 Concentration units; and

 Mass units.

Concentration units, such as lb VOC/gallon, most frequently appear in rules (RACT, NSPS,

NESHAP etc. ), new source review (NSR) permits, and Title V permits and are designed to

reduce emissions from existing sources and limit emissions from new sources. These standards

are written for specific operations in specific industries to achieve emission reducti ons over

current practices.

Mass units, such as lb/hr or tons/yr, are needed to complete TCEQ NSR permit applications,

emission inventories, and emission fee calculations, and are used as inputs into atmospheric

dispersion models. The dispersion models ar e used to demonstrate compliance with the National

Ambient Air Quality Standards (NAAQS) and TCEQ state property line standards for particulate

matter and H 2 S, as well as providing the off

- property concentrations of all species to be emitted

by the facilit y to demonstrate that the facility emissions will not be detrimental to public health.

The data required to complete the calculation depends on the units that the standard or limit

contains. The most common units and the required data appear in Tables 6 through 10.23

TABLE 4

SURFACE COATING CALCULATIONS

- SOLVENT EMISSIONS

DATA REQUIREMENTS AND DATA SOURCES

Concentration Limits

lb VOC/gal of coating lb VOC/gal solids lb VOC/gal solids applied

Coating Data Re quired Units Data Source Units Data Source Units Data Source

Coating Consumption lb/gal MSDS lb/gal MSDS lb/gal MSDS

Multiple Component Mixing

Ratio lb/gal MSDS lb/gal MSDS lb/gal MSDS

Thinning Ratio lb/gal MSDS lb/gal MSDS lb/g al MSDS

Coating Density lb/gal MSDS lb/gal MSDS lb/gal MSDS

Coating/Component VOC

Content lb/gal MSDS lb/gal MSDS lb/gal MSDS

Coating Water Content lb/gal MSDS lb/gal MSDS lb/gal MSDS

Coating Exempt Solv ent

Content lb/gal MSDS lb/gal MSDS lb/gal MSDS

Coating Volume VOC

Content Percent MSDS/Technical Data Percent MSDS/Technical Data Percent MSDS/Technical Data

Sheet/Vendor Sheet/Vendor Sheet/Vendor

Thinner Density lb/gal MSDS lb/gal M SDS lb/gal MSDS

VOC Control Efficiency Percent Control Equipment

Vendor Percent Control Equipment

Vendor Percent Control Equipment

Vendor

Coating Volume Solids

Content Percent MSDS/Technical Data Percent MSDS/Technical Data Perce nt MSDS/Technical Data

Sheet/Vendor Sheet/Vendor Sheet/Vendor

Transfer Efficiency NA NA Percent Tables/Calculation/

Testing24

TABLE 5

SURFACE COATING CALCULATIONS

- SOLVENT EMISSIONS

DATA REQUIREMENTS AND DATA SOURCES

Mass Units

lb/hr tons/yr

Coating Data Required Units Data Source Units Data Source

Coating Consumption gal/hr Plant Production Data gal/yr Plant Production Data

Multiple Component Mixing Ratio None MSDS/Technical Data None MSDS/Technical Data

Sheet/Vendor Sheet/Vendor

Thinning Ratio None MSDS/Technical Data None MSDS/Technical Data

Sheet/Vendor Sheet/Vendor

Coating Density lb/gal MSDS lb/gal MSDS

Coating/Component VOC Content lb/gal MSDS lb/gal M SDS

Coating Exempt Solvent Content lb/gal MSDS lb/gal MSDS

Thinner Density lb/gal MSDS lb/gal MSDS

Thinner VOC Content lb/gal MSDS lb/gal MSDS

Thinner Exempt Solvent Content lb/gal MSDS lb/gal MSDS

VOC Emission Distribution Percent Flashoff Curves or Testing Percent Flashoff Curves or

Testing

VOC Control Efficiency Percent Control Equipment Vendor Percent Control Equipment

Vendor25

TABLE 6

SURFACE COATING CALCULATIONS

- SOLIDS EMI SSIONS

DATA REQUIREMENTS AND DATA SOURCES

Mass Units

lb/hr tons/yr

Coating Data Required Units Data Source Units Data Source

Coating Consumption gal/hr Plant Production Data gal/yr Plant production data

Multiple Comp onent Mixing Ratio None MSDS/Technical Data None MSDS/Technical Data

Sheet/Vendor Sheet/Vendor

Thinning Ratio None MSDS/Technical Data None MSDS/Technical Data

Sheet/Vendor Sheet/Vendor

Coating Density lb/gal MSDS lb/gal MSDS

Thinn er Density lb/gal MSDS lb/gal MSDS

Coating/Component Solids Content lb/gal MSDS lb/gal MSDS

Transfer Efficiency Percent Tables/Calculation/Testing Percent Tables/Calculation/Testing

Filter Efficiency Percent Control Equipment Ve ndor Percent Control Equipment Vendor

Fall Out Percent Tables/Vendor Percent Tables/Vendor26

TABLE 7

SURFACE COATING CALCULATIONS

- SOLVENT SPECIES EMISSION RATES

DATA REQUIREMENTS AND DATA SOURCES

Species Mass E mission Rates

lb/hr tons/yr

Coating Data Required Units Data Source Units Data Source

Coating Consumption gal/hr Plant Production Data gal/yr Plant production data

Multiple Component Mixing Ratio None MSDS/Technical Data None MS DS/Technical Data

Sheet/Vendor Sheet/Vendor

Thinning Ratio None MSDS/Technical Data None MSDS/Technical Data

Sheet/Vendor Sheet/Vendor

Coating Density lb/gal MSDS lb/gal MSDS

Coating/Component Species Percent MSDS Percent MSDS

Thinner Density lb/gal MSDS lb/gal MSDS

Thinner Species Percent MSDS Percent MSDS

VOC Emission Distribution Percent Flashoff Curves or Testing Percent Flashoff Curves or Testing

VOC Control Efficiency Percent Control Eq uipment Vendor Percent Control Equipment Vendor27

TABLE 8

SURFACE COATING CALCULATIONS

- SOLIDS SPECIES EMISSION RATES

DATA REQUIREMENTS AND DATA SOURCES

Species Mass Emission Rates

lb/hr tons/yr

Coating Dat a Required Units Data Source Units Data Source

Coating Consumption gal/hr Plant Production Data gal/yr Plant production data

Multiple Component Mixing Ratio None MSDS/Technical Data None MSDS/Technical Data

Sheet/Vendor Sheet/Vendor

Thi nning Ratio None MSDS/Technical Data None MSDS/Technical Data

Sheet/Vendor Sheet/Vendor

Coating Density Lb/gal MSDS lb/gal MSDS

Thinner Density Lb/gal MSDS lb/gal MSDS

Coating/Component Species Lb/gal MSDS lb/gal MSDS

Transfer Efficiency Percent Tables/Calculation/Testing Percent Tables/Calculation/Testing

Filter Efficiency Percent Control Equipment Vendor Percent Control Equipment Vendor

Fall Out Percent Tables/Vendor Percent Tables/Vendor

CALCULATION APPROACH

The actual emission calculations for each set of units may be determined either by hand or by

using a computer. Hand methods are impractical for facilities that use large numbers of coatings

or have a large number of emission s ources. However, hand calculations illustrate the

calculation approach for each set of units and are presented below.28 Coating As

- Applied VOC Content

Single Component Coating

Data Requirements

Coating VOC content from MSDS or technical data sheet

Since t he coating is not mixed with any thinners or any other components the as

- applied VOC

content will be as stated.

Single Component Coating with Thinner

Data Requirements

Coating VOC Content 2.8 lb VOC/gal

Thinner VOC Content 7.3 lb VOC/gal

Thinning Ratio 10 : 1

10 Parts Coating 5 gal

1 Part thinner 0.5 gal

11 Parts Mixed Coating 5.5 gal

Calculate VOC Content

2.8 lb VOC 5 gal + 7.3 lb VOC 0.5 gal =17.65 lb VOC

Gal gal

17.65 lb VOC =3.20 lb VOC/gal coating

5.5 gal29

Multiple Component Coating

Data Requirements

Part A VOC Content 2.8 lb VOC/gal

Part B VOC Content 1.2 lb VOC/gal

Mixing Ratio 2 : 1

2 Parts Part A 1 gal

1 Part Part B 0.5 gal

3 Parts Mixed Coating 1.5 gal

Calculate VOC Content

2.8 lb VOC 1 gal + 1.2 lb VOC 0.5 gal =3.4 lb VOC

Gal gal

3.4 lb VOC =2.26 lb VOC/gal coating

1.5 gal30

Multiple Component Coating with Thinner

Data Requirements

Part A VOC Content 2.8 lb VOC/gal

Part B VOC Content 1.2 lb VOC/gal

Thinner VOC Content 7.3 l b VOC/gal

Mixing Ratio 2 : 1

2 Parts Part A 1 gal

1 Part Part B 0.5 gal

3 Parts Mixed Coating 1.5 gal

Thinning Ratio 10 : 1

10 Parts Coating 1.5 gal

1 Part thinner 0.15 gal

11 Parts Mixed Coating 1.65 gal

Calculate VOC Content

2.8 lb VOC 1 gal + 1.2 lb VOC 0.5 gal + 7.3 lb VOC 0.15 gal =4.49 lb VOC

Gal gal gal

4.49 lb VOC =2.72 lb VOC/gal

1.65 gal

Coating VOC Content

- Less Water and Exempt Solvent

In addition to calculating coating VO C content as applied on a per gallon of coating basis, many

State and federal rules require that the as

- applied coating VOC content be determined on a per

gallon of coating basis, less water and exempt solvent. This also requires that the volume of

water and exempt solvent (gallons) be known for the coating.31

Data Requirements

Coating VOC Content 2.8 lb VOC/gal

Coating Water Content 1.0 lb water/gal

Water Density 8.34 lb/gal

Coating Exempt Solvent Content 0.5 lb ES/gal

Exempt Solvent Density 6.64 l b/gal

Calculate Coating Volume Water and Exempt Solvent

1.0 lb Water Gal
= 0.12 gal

Gal 8.34 lb

0.5 lb ES Gal
= 0.075 gal

Gal 6.64 lb

Calculate Coating VOC Content

Coating VOC Content (lb) = lb VOC/gal c oating (less Water and ES)

1 (gal)

– Coating Water Volume (gal)

- Coating ES Volume (gal)

2.8 lb VOC/gal = 2.8 lb VOC = 3.47 lb VOC/ gal coating (less Water and ES)

1 gal

- 0.12 gal

- 0.075 gal 0.805 gal

Coating VOC Content per Gallon of Solids

Some State and federal rules contain an alternate standard that requires the as

- applied coating

VOC content be determined on a per gallon of solids basis. This set of units requires that the

volume of VOC, water, and exempt solvent (gall ons) be known for the coating.32

Data Requirements

Coating VOC Content 2.8 lb VOC/gal

Solvent System Density 7.1 lb/gal

Coating Water Content 1.0 lb water/gal

Water Density 8.34 lb/gal

Coating Exempt Solvent Content 0.5 lb ES/gal

Exempt Solvent Den sity 6.64 lb/gal

Calculate Coating Volume VOC, Water and Exempt Solvent

2.8 lb VOC gal
= 0.394 gal

Gal 7.1 lb

1.0 lb Water gal
= 0.12 gal

Gal 8.34 lb

0.5 lb ES gal
= 0.075 gal

Gal 6.64 lb

Calculate Coa ting VOC Content

Coating VOC Content (lb) = lb VOC/gal solids

1 (gal)

- Coating VOC Volume (gal)

- Coating Water Volume (gal)

- Coating ES Volume (gal)

2.8 lb VOC/gal = 2.8 lb VOC = 6.81 lb VOC/ gal solids

1 gal

- 0.394 gal

- 0. 12 gal

- 0.075 gal 0.411 gal

Coating VOC Content per Gallon of Solids Applied

The final set of VOC concentration units are commonly seen in NSPS standards and have units

of lb VOC/gal solids applied. This type of standard allows for greater complian ce flexibility due

to allowing transfer efficiency to be taken into consideration. In other words, a higher VOC33

content coating (lb VOC/gal coating) can be used to achieve compliance with the standard as

long as a high transfer efficiency application syst em is used.

Data Requirements

Coating VOC Content 2.8 lb VOC/gal

Solvent System Density 7.1 lb/gal

Coating Water Content 1.0 lb water/gal

Water Density 8.34 lb/gal

Coating Exempt Solvent Content 0.5 lb ES/gal

Exempt Solvent Density 6.64 lb/gal

Tr ansfer Efficiency 0.60

Calculate Coating Volume VOC, Water and Exempt Solvent

2.8 lb VOC Gal
= 0.394 gal

Gal 7.1 lb

1.0 lb Water Gal
= 0.12 gal

Gal 8.34 lb

0.5 lb ES Gal
= 0.075 gal

Gal 6.64 lb

Calculate Coating VOC Cont ent

Coating VOC Content (lb) = lb VOC/gal solids applied

1 (gal)

- Coating VOC Volume (gal)

- Coating Water Volume (gal)

- Coating ES Volume (gal) TE

2.8 lb VOC/gal = 2.8 lb VOC = 11.35 lb VOC/ gal solids applied

1 gal

– 0.3 94 gal

- 0.12 gal

- 0.075 gal 0.6 0.411 gal 0.634

Coating HAP Content

- Pounds Organic HAP per Pound of Coating Solids

The concentration limits in t he National Emission Standard for Hazardous Air Pollutants

(NESHAPs) under 40 CFR Part 63 (MACT) for som e coating operations contain limits in units

of Lb HAP/Lb of c oating solids

.

Data Requirements

Coating Density 11.5 lb/gal

Coating VOC Content 3.5 lb VOC/gal

Coating PM Content 8.0 lb PM/gal

Coating HAP Content 2. 0 lb HAP/gal

Calculate Coat ing HAP Content

2. 0 lb HAP Gal
= 0. 25 lb HAP/lb PM

Gal 8.0 lb PM35

Coating Mass Emission Rates

Emission Rates

– Parts Dry in the Spray Booth

Data Requirements

Coating VOC Content 3.5 lb VOC/gal

Coating PM Content 8.0 lb PM/gal

Daily Coating Co nsumption 6.0 gal

Spray Time 3.0 hr

Annual Coating Consumption 4750 gal/yr

Transfer Efficiency 0.60

Filter Efficiency

- Booth 99.00%

Minimum Efficiency Removal Value 1 4

Filter Efficiency 3.0

- 10.0 microns 90.00%

Filter Efficiency 1.0

- 3.0 mi crons 90.00%

PM Fallout PM 30 98.56%

PM Fallout PM 10 99.87%

PM Fallout PM 2.5 99.99%

Calcu late Short Term VOC Emission Rate

3.5 lb VOC 6.0 gal
= 7.0 lb VOC/hr

G al 3 hr

Calculate Short Term PM 30 Emission Rate

8.0 lb PM 6.0 gal 1

- 0.6 1

- 0. 9 9 1

- 0.9 856 = 0.00 0 9 lb PM 30 /hr

Gal 3 hr36

Calculate Short Term PM 10 Emission Rate

8.0 lb PM 6.0 gal 1

- 0.6 1

- 0.90 1

- 0.9987 = 0.00 08 lb PM 10 /hr

Gal 3 hr

Calculate Short Term PM 2.5 Emission Rate

8.0 lb PM 6.0 gal 1

- 0.6 1

- 0.90 1

- 0.9999 = 0.00 01 lb PM 2.5 /hr

Gal 3 hr

Calculate Annual VOC Emission Rate

3.5 lb VOC 4750 gal 1 ton = 8.31 ton VOC/yr

gal Yr 2000 lb

Calculate Annual PM 30 Emission Rate

8.0 lb PM 4750 gal 1

- 0.6 1

- 0.99 1

- 0.9856 1 ton = 0.0 0 11 ton PM 30 /yr

Gal Yr 2000 lb

Calculate Annual PM 10 Emission Rate

8.0 lb PM 4750 gal 1

- 0.6 1

- 0.90 1

- 0.9987 1 ton = 0.00 10 ton PM 10 /yr

Gal Yr 2000 lb

Calculate Annual PM 2.5 Emission Rate

8.0 lb PM 4750 gal 1

- 0.6 1

- 0.90 1

- 0.9999 1 ton = 0.00 01 ton PM 2.5 /yr

Gal Yr 2000 lb37

Emission Rates

– Parts Dry on the Conveyor and Oven

Coating VOC Content 3.5 lb VOC/gal

Daily Coating Consumption 6.0 gal

Spray Time 3.0 hr

Annual Coating Consumption 4750 gal/yr

Transfer Efficiency 0.60

Solvent Loss in Booth 0.30

Solvent Loss on Conveyor 0.09

Solvent Loss in the Oven 0.61

Calculate Total Short Term VOC Emissions for the Coating Line

3.5 lb VOC 6.0 gal
= 7.0 lb VOC/hr

Gal 3 hr38

Calculate Short Term VOC Em ission Rate for Each Coating Line Segment

Spray Booth

Part Overspray

TE Booth

Flashoff 1

- TE

7.0 lb VOC 0.60 0.30 + 7.0 lb VOC 1

- 0.6 = 4.06 lb VOC/hr

hr hr

Conveyor

TE Conveyor Flashoff

7.0 lb VOC 0.60 0.09 = 0.37 l b VOC/hr

hr

Drying Oven

TE Oven

Flashoff

7.0 lb VOC 0.60 0.61 = 2.56 lb VOC/hr

hr

Calculate Total Annual VOC Emissions for the Coating Line

3.5 lb VOC 4750 gal 1 ton = 8.31 ton VOC/yr

Gal Yr 2000 lb39

Calculate Annual VOC Em ission Rate for Each Coating Line Segment

Spray Booth

Part Overspray

TE Booth Flashoff 1

- TE

8.31 ton VOC 0.60 0.30 + 8.31 ton VOC 1

– 0.6 = 4.81 ton VOC/yr

yr yr

Conveyor

TE Conveyor Flashoff

8.31 ton VOC 0.60 0.09 = 0.45 ton VOC/yr

yr

Drying Oven

TE Oven

Flashoff

8.31 ton VOC 0.60 0.61 = 3.04 ton VOC/yr

yr

Only VOC emission rates are calculated in this example since it is assumed that all of the PM

emissions occur within the booth and the emission calculation will be the same as in the previous

example. Most spray booths that have a face velocity of 100

– 200 ft/min will achieve 100

percent capture of both PM and VOC emissions. Actual painting is not the only source of

emissions in these examples. Cleanup solvent can make a significant contribution to the total

annual solvent emissions for the facility. Because cleanup and coating application cannot occur

simultaneously, hourly cleanup emission rates should be calculated separately. The short

- term40

permit limit will be the higher of the two emission rates. Cleanup emission rates should be

determined using the same methodology as used in the VOC emission rate calculations noted

above with consideration given to the amount of spent wash so lvent recovered during cleanup.

Coating Species Mass Emission Rates

Data Requirements

Coating Density 11.5 lb/gal

Daily Coating Consumption 6.0 gal

Spray Time 3.0 hr

Annual Coating Consumption 4750 gal/yr

Transfer Efficiency 0.60

Filter Efficienc y 0.9 9

Fall Out Factor 0.9 856

Mixed Coating Formulation

Coating Weight Constituent HAP

Constituent CAS No. Fraction Type (P/V/ES) (Y/N)

Methyl Ethyl Ketone 78

- 93

- 3 0.20 V Y

Acetone 67

- 64

- 1 0.05 ES N

Methanol 67

- 56

- 1 0.10 V Y

VM&P Naphtha 8032

- 32

- 4 0.05 V N

Strontium Chromate 6/2/89 0.10 P Y

Titanium Dioxide 13463

- 67

- 7 0.15 P Y

Iron Oxide 1332

- 37

- 2 0.05 P N

Epoxy Resin NA 0.30 P N41

Calculate Short Term Species Emission Rates

Volatile Species

11.5 lb 6.0 gal Wt. Fraction
= 23.0 Weight Fraction lb/hr

Gal 3 hr

Coating Weight Weight Emission

Constituent Fraction Fraction lb/hr Rate (lb/hr)

Methyl Ethyl Ketone 0.20 23.0 4.60

Acetone 0.05 23.0 1.15

Methanol 0.10 23.0 2.30

VM&P Naphtha 0.05 23.0 1.1 5

Particulate Species

1

- TE 1

- FE 1

- FO

11.5 lb 6.0 gal Wt.

Fraction 1

- 0.60 1

- 0.9 9 1

- 0.9 856 = 0.0 0 1 3 Weight Fraction lb/hr

gal 3 hr

Coating Weight Weight Emission

Constituent Fraction Fraction lb/hr R ate (lb/hr)

Strontium Chromate 0.10 0.0 0 1 3 0.00 0 1

Titanium Dioxide 0.15 0.0013 0.00 0 2

Iron Oxide 0.0 5 0.0013 0.000 1

Epoxy Resin 0. 30 0.0013 0.00 0 4

Calculate Annual Species Emission Rates

Volatile Species

11.5 lb 4750 gal 1 Ton Wt. Fr action
= 27.3 Weight Fraction ton/yr

gal Yr 2000 lb42

Coating Weight Weight Emission

Constituent Fraction Fraction ton/yr Rate (ton/yr)

Methyl Ethyl Ketone 0.20 27.3 5.46

Acetone 0.05 27.3 1.36

Methanol 0.10 27.3 2.73

VM&P Naphtha 0.05 27. 3 1.36

Particulate

Species

1

- TE 1

- FE 1

- FO

11.5 lb 4750 gal 1 Ton Wt.

Fraction 1

- 0.60 1

- 0.9 9 1

- 0.9 856 = 0.0 0 16 Weight Fraction ton/yr

gal Yr 2000 lb

Coating Weight Weight Emission

Constituent Fraction F raction ton/yr Rate (ton/yr)

Strontium Chromate 0.10 0.0 0 16 0.00 0 16

Titanium Dioxide 0.15 0. 0 016 0.00 0 24

Iron Oxide 0.05 0.0 0 16 0.00 0 08

Epoxy Resin 0.30 0.0 0 16 0.00 0 48

The emission distribution for the individual volatile species can be determine d using the solvent

loss fractions (flashoff fractions) used in the previous example.

Calculation of HAPS

Since the adoption of the Federal Clean Air Act Amendments of 1990, an additional set of

calculations may be necessary to determine the emission ra te of hazardous air pollutants (HAPs).

A number of the National Emission Standards for Hazardous Air Pollutants (NESHAPs) under

40 CFR 63 apply to surface coating operations and contain concentration limits (lb HAP/gal) that43

affected facilities are requir ed to certify compliance. In addition, the applicability of these rules

and the applicability of Title V operating permits under 40 CFR 70 may also be triggered solely

by HAP emissions if they exceed 10 tpy for any individual HAP and 25 tpy in the aggrega te for a

site.

Fortunately, HAP emissions can be calculated using the same methods as VOC and speciated

emissions. The only changes to the methods is simply the substitution of coating HAP content

for VOC content to determine compliance with concentration limits. To determine if the 10/25

tpy thresholds are exceeded, the speciated emission calculations need only be completed for the

HAP species (see definitions) and compared to the 10 tpy threshold for any individual HAP

species and summed to determine if the total exceeds 25 tpy.

Addition of Emission Controls for Solvents

All of the coating scenarios evaluated above do not consider the use of solvent emission controls.

Controls are generally required for three reasons as follows:

 The emission standard i n federal, state or local rules cannot be met;

 To meet the requirements of Best Available Control Technology (BACT) in federal,

and TCEQ permits; and

 To provide acceptable off property concentrations of the various solvent species to

insure that there will be no adverse effects on public health.

Emission controls for surface coating can either be process controls or add

- on controls. Process

controls involve changing the basic process to provide greater efficiency in the application of

coatings and in the u se of solvents. Process controls typically consist of increasing transfer

efficiency (less coating is used per part) and through the use of high solids coatings (less coating

and solvent used per part). Add

- on controls provide significant emission reduct ions as long as

the unit is used to control the correct portion of the coating line (usually the spray booths and

flashoff tunnel) and the emission capture efficiency is high. The most common types of44

emission controls are thermal oxidizers in one of many configurations or carbon adsorption

systems. Carbon adsorption systems can work nearly as well as thermal systems provided the

emission species are well known and do not change over time.

The emission reductions for process controls can be determined thr ough substituting the revised

transfer efficiencies and coating solvent contents into the emission calculation methods covered

previously. For add

- on controls, the emission calculation methods need to be modified through

the use of an additional term that includes the control efficiency (CE) of the add

- on control

equipment as follows:

Addition of Emission Controls

Emission Rate 1

- CE =

Emission Rate 1

- 0.98 = Emission Rate X 0.02

This calculation approach works for either concentration units or mass units without

modification.

AUTOMATION OF EMISSION CALCULATIONS

The emission calculation methods previously described present an orderly approach for hand

calculations but are still far too cumbersome to be used on a daily basis for compliance

demonstrations or for use in permit applications. Fortunately, spreadsheets and databases can be

used to simplify the process and reduce the amount of repetitive data entry through the use of

tables that store specific types of information as follows:

 Coating and solvent properties such as density, VOC content, mix ratios, species, and

type, etc.;45

 Configuration of the facility such as number of booths, filter efficiencies, and VOC

control efficiencies;

 Dynamic data that includes transfer efficiency and changes in flashoff due to changes

in coatings and conveyor speed; and

 Daily data that includes the amount of each coating and solvent mixed, applied in

each booth or coating line, and transferred to waste.

This type of approach al lows the data to be easily updated, sorted by type of product (polyester,

epoxy etc.), type of air contaminant (P, V, ES, HAP), date, or booth. As can be seen from the

emission calculation examples, a great deal of data is common between the various emiss ion

standard and the software can draw from common tables to produce a variety of preformatted

reports to demonstrate regulatory compliance or regulatory applicability. In addition, emission

calculation automation can also provide management with useful i nformation on production

costs such as the cost of coating per part, comparison of the amount of coating used by different

crews on the same parts, and provide opportunities for process improvement and reductions in

operating costs.

CONCLUSIONS

Emission ca lculations for surface coating facilities have become more important than ever for

facilities to demonstrate compliance with regulatory and permit limits as well as initially setting

permit emission limits. This task can be simplified if accurate coating and facility data is

collected through a partnership with coating and equipment vendors, facility production

operations, and facility management. Understanding how to collect this data and calculate both

concentration and mass emission rates will allow th e environmental staff to more easily prepare

permit applications, and upon issuance of the permit more easily demonstrate compliance with

permit and other regulatory emission limits.46

REFERENCES

1. Clean Air Act, §112[42 USC 7142] National Emission Standard f or Hazardous Air

Pollutants, §112(b) List of Pollutants

2. Texas Commission on Environmental Quality

– 200 5 Emission Inventory Guidelines

–

200 5 . Document No. RG

- 360

_ 0 5 , December 200 5 (available online at:

http://www.tceq.state.tx.us/comm_exec/forms_pubs/pubs/rg/rg

- 360_05/rg

360_05_1390103.pdf ).

3. Texas Commission on Environmental Quality

– General Air Quality Rules, 30 TAC

§101.1, June 15, 2005 (availabl e online at:

http://www.tceq.state.tx.us/assets/public/legal/rules/rules/pdflib/101a.pdf ).

4. Texas Commission on Environmental Quality

– Control of Air Pollution f rom Volatile

Organic Compounds, 30 TAC §115.10 and 30 TAC §115.420, May 5, 2005 (available

online at: http://www.tceq.state.tx.us/assets/public/legal/rules/rules/p dflib/115a.pdf and

http://www.tceq.state.tx.us/assets/public/legal/rules/rules/pdflib/115e.pdf ).

5. Air Pollution Engineering Manual, AP

- 40. 2 nd ed., J. .A. Daniel son, Ed.; Air Pollution

Control District of Los Angeles, Environmental Protection Agency, Office of Air and

Water Programs, Office of Air Quality Planning and Standards, Research Triangle Park,

NC, May 1973

6. Air Pollution Engineering Ma nual. Anthony J. Buonicore and Wayne T. Davis, Ed., Air

and Waste Management Association, 1992, p. 362

7. Texas Natural Resource Conservation Commission

– Air Permit Technical Guidance for

Coating Sources: Surface Coating Operations, April 2001

8. Calculations on particle size paints prepared by D.T. Emery of Phillips Petroleum

Company in Bartlesville, Oklahoma, January 1993;47

9. Droplet distribution information prepared by Dan Carroll of Coltec Industries in Des

Moines, Iowa, November 1992;

10. Determination of Particl e Size Distributions for Airless Spray prepared by K.C. Kwok,

Ph.D. for Rescar Inc. of Downers Grove, Illinois, January 1994;

11. IWATA Test Report supplied by Glen Nelson, Project Manager for Binks Manufacturing

Company of Franklin Park, Illinois, July 1993; and

12. CORROSION 95

- Paper No. 634, Cost Effective Solutions Today and Beyond 2000 with

Supercritical Fluid Technology prepared by R.J. Woods and D.C. Busby, Union Carbide

Corporation, South Charleston, WV.