Chapter 391-3-1 Rules for Air Quality Control 

PROPOSED AMENDMENTS TO THE RULES OF THE

DEPARTMENT OF NATURAL RESOURCES 

ENVIRONMENTAL PROTECTION DIVISION 

RELATING TO AIR QUALITY, CHAPTER 391-3-1

The Rules of the Department of Natural Resources, Chapter 391-3-1, Air Quality Control are 

hereby amended, added to, repealed in part, revised, as hereinafter explicitly set forth in the 

attached amendments, additions, partial repeals, and revisions for specific rules, or such 

subdivisions thereof as may be indicated. 

[Note: Underlined text is proposed to be added. Lined-through text is proposed for 

deletion.] 

Rule 391-3-1-.02(2)(a)6., “VOC Emission Standards, Exemptions, Area Designations, 

Compliance Schedules and Compliance Determinations,” is being amended to read as 

follows: 

6. VOC Emission Standards, Exemptions, Area Designations, Compliance Schedules and 

Compliance Determinations 

(i) Exemptions and Area Designations. 

(I) Sources located outside Cherokee, Clayton, Cobb, Coweta, DeKalb, Douglas, Fayette, 

Forsyth, Fulton, Gwinnett, Henry, Paulding, and Rockdale counties whose potential emissions 

of volatile organic compounds are not more than 100 tons per year shall not be subject to 

subparagraphs (u), (v), (x), (aa) through (ff) [inclusive], (hh), (kk), (ll), (nn), and (qq) of this 

section 391-3-1-.02(2). 

(II) Sources used exclusively for chemical or physical analysis or determination of product 

quality and commercial acceptance shall not be subject to subsections (t) through (ff) [inclusive], 

(hh) through (nn) [inclusive], (qq), and (tt) of this section 391-3-1-.02(2), provided: 

I. The operation of the source is not an integral part of the production process; and provided; 

II. The emissions from the source do not exceed 800 pounds in any calendar month; and 

provided; 

III. The exemption from such source is approved in writing by the Director. 

(III) Sources located within Cherokee, Clayton, Cobb, Coweta, DeKalb, Douglas, Fayette, 

Forsyth, Fulton, Gwinnett, Henry, Paulding, or Rockdale counties whose actual emissions of 

volatile organic compounds are less than 15 pounds per day shall not be subject to subsections 

(u), (v), (x), (aa) through (ff) [inclusive], (kk), (ll), and (qq) of this section 391-3-1-.02(2). 

(IV) Coatings, inks and other VOC-containing materials in use at sources of VOC emissions 

subject to any limitations or requirements of subsections (t) through (aa) [inclusive], (ii), (jj), 
Chapter 391-3-1 Rules for Air Quality Control 

(mm), and (tt) of this section 391-3-1-.02(2) shall not be subject to any requirements of such 

subsections, provided the source’s total aggregate use of such materials is not in excess of 55 

gallons per year and such exemption is approved in writing by the Division. 

(V) Sources located within Barrow, Bartow, Carroll, Hall, Newton, Spalding, or Walton Counties 

whose actual emissions of volatile organic compounds are greater than or equal to 15 pounds 

per day shall be subject to subparagraphs (u), (v), (x), (aa) through (ff) [inclusive], (hh), (kk), (ll), 

(nn), and (qq) of this section 391-3-1-.02(2) effective January 1, 2015. The requirements of this 

subparagraph (V) will no longer be applicable if the counties specified in this subparagraph (V) 

are re-designated to attainment for the 1997 National Ambient Air Quality Standard for ozone 

prior to January 1, 2015. In the event the 1997 National Ambient Air Quality Standard for ozone 

is violated in these counties or the counties specified in subparagraph (III) above, the 

requirements of this subparagraph (V) will only be reinstated if the Director determines that the 

measure is necessary to meet the requirements of the contingency plan. 

(ii) Compliance Schedules. 

(I) All sources of VOC emissions subject to any limitation or requirement of, or under, section 

391-3-1-.02(2) prior to the effective date of this amended Rule 391-3-1-.02, shall be in 

compliance or on an approved compliance schedule. 

(iii) Compliance Determinations. 

(I) Compliance determinations for coatings expressed as pounds of VOC per gallon of coating, 

excluding water, shall treat organic compounds that are not defined as VOCs as water for 

purposes of calculating the “excluding water” part of the coating composition. 

Rule 391-3-1-.02(2)(kkk), “VOC Emissions from Aerospace Manufacturing and Rework 

Facilities,” is being amended to read as follows: 

(kkk) VOC Emissions from Aerospace Manufacturing and Rework Facilities. 

1. No person shall cause, let, permit, suffer, or allow the emissions of VOC from the coating of 

aerospace vehicles or components to exceed: 

(i) 2.9 pounds per gallon of coating, excluding water and exempt solvents, delivered to a 

coating applicator that applies primers. For general aviation rework facilities, the VOC limitation 

shall be 4.5 pounds per gallon of coating, excluding water and exempt solvents, delivered to a 

coating applicator that applies primers. 

(ii) 3.5 pounds per gallon of coating, excluding water and exempt solvents, delivered to a 

coating applicator that applies topcoats (including self-priming topcoats). For general aviation 

rework facilities, the VOC limitation shall be 4.5 pounds per gallon of coating, excluding water 

and exempt solvents, delivered to a coating applicator that applies topcoats (including selfpriming topcoats). 

(iii) The VOC content limits listed in Table (kkk) -1 below expressed in pounds per gallon of 

coating, excluding water and exempt solvents, delivered to a coating applicator that applies 

specialty coatings. 
Chapter 391-3-1 Rules for Air Quality Control 

TABLE (kkk)1 Specialty Coating VOC Limitations 

Coating Type 

VOC Content 

Limit 

(lb/gal) 

Ablative Coating 5.0 

Adhesion Promoter 7.4 

Adhesive Bonding Primers: 

 Cured at 250oF or below 7.1 

 Cured above 250oF 8.6 

Adhesives: 

 Commercial Interior Adhesive 6.3 

 Cyanoacrylate Adhesive 8.5 

 Fuel Tank Adhesive 5.2 

 Nonstructural Adhesive 3.0 

 Rocket Motor Bonding Adhesive 7.4 

 Rubber-based Adhesive 7.1 

 Structural Autoclavable Adhesive 0.5 

 Structural Nonautoclavable Adhesive 7.1 

Antichafe Coating 5.5 

Bearing Coating 5.2 

Caulking and Smoothing Compounds 7.1 

Chemical Agent-Resistant Coating 4.6 

Clear Coating 6.0 

Commercial Exterior Aerodynamic Structure Primer 5.4 

Compatible Substrate Primer 6.5 

Corrosion Prevention Compound 5.9 

Cryogenic Flexible Primer 5.4 

Cryoprotective Coating 5.0 

Dry Lubricative Material 7.3 

Electric or Radiation-Effect Coating 6.7 

Electrostatic Discharge and Electromagnetic Interference 

(EMI) Coating 6.7 

Elevated Temperature Skydrol Resistant Commercial 

Primer 6.2 

Epoxy Polyamide Topcoat 5.5 

Fire-Resistant (Interior) Coating 6.7 

Flexible Primer 5.3 

Flight-Test Coatings: 

 Missile or Single Use Aircraft 3.5 

 All Other 7.0 

Fuel-Tank Coating 6.0 

High-Temperature Coating 7.1 

Insulation Covering 6.2 

Intermediate Release Coating 6.3 

Lacquer 6.9 

Maskants: 

 Bonding Maskant 10.3 
Chapter 391-3-1 Rules for Air Quality Control 

Coating Type 

VOC Content 

Limit 

(lb/gal) 

 Critical Use and Line Sealer Maskant 8.5 

 Seal Coat Maskant 10.3 

Metallized Epoxy Coating 6.2 

Mold Release 6.5 

Optical Anti-Reflective Coating 6.3 

Part Marking Coating 7.1 

Pretreatment Coating 6.5 

Rain Erosion-Resistant Coating 7.1 

Rocket Motor Nozzle Coating 5.5 

Scale Inhibitor 7.3 

Screen Print Ink 7.0 

Sealants: 

 Extrudable/Rollable/Brushable Sealant 2.3

 Sprayable Sealant 5.0 

Silicone Insulation Material 7.1 

Solid Film Lubricant 7.3 

Specialized Function Coating 7.4 

Temporary Protective Coating 2.7 

Thermal Control Coating 6.7 

Wet Fastener Installation Coating 5.6 

Wing Coating 7.1 

(iv) 5.2 pounds per gallon of coating, excluding water and exempt solvents, delivered to a 

coating applicator that applies Type I chemical milling maskants. 

(v) 1.3 pounds per gallon of coating, excluding water and exempt solvents, delivered to a 

coating applicator that applies Type II chemical milling maskants. 

(vi) The following aerospace activities are exempt for the coating emission limits in paragraphs 

1.(i) through (v): touchup, aerosol, and DOD classified coatings; coatings used on space 

vehicles; and facilities that comply with the low volume usage exemption in paragraph 10. 

2. The emission limitations in this subsection shall be achieved by: 

(i) The application of low solvent coating technology where each and every coating meets the 

specified applicable limitation expressed in pounds of VOC per gallon of coating, excluding 

water and exempt solvents, stated in section 1 of this subsection; or 

(ii) The application of low solvent coating technology where the monthly volume-weighted 

average VOC content of each specified coating type meets the specified applicable limitation 

expressed in pounds of VOC per gallon of coating, excluding water and exempt solvents, stated 

in section 1 of this subsection; averaging is not allowed between primers, topcoats (including 

self-priming topcoats), specialty coating types, Type I milling maskants, and Type II milling 

maskants or any combination of the above coating categories; or 
Chapter 391-3-1 Rules for Air Quality Control 

(iii) Control equipment, including but not limited to incineration, carbon adsorption and 

condensation, with a capture system approved by the Director, provided that the control system 

has a VOC reduction efficiency of 81 percent or greater. 

3. Each owner or operator of an aerospace manufacturing and/or rework operation shall apply 

all non-exempt primers and topcoats utilizing one or more of the application techniques 

specified below: 

(i) Flow/curtain application; 

(ii) Dip coat application; 

(iii) Roll coating; 

(iv) Brush coating; 

(v) Cotton-tipped swab application; 

(vi) Electrodeposition (dip) coating; 

(vii) High-volume low-pressure (HVLP) spraying; 

(viii) Electrostatic spray application; or 

(ix) Other coating application methods that achieve emission reductions equivalent to HVLP or 

electrostatic spray application methods, as determined by the Director. 

4. Each owner or operator of an aerospace manufacturing and/or rework operation shall ensure 

that all application devices used to apply primers and topcoats (including self-priming topcoats) 

are operated according to company procedures, local specified operating procedures, and/or 

the manufacturer’s specifications, whichever is most stringent, at all times. Equipment modified 

by the owner or operator shall maintain a transfer efficiency equivalent to HVLP or electrostatic 

spray application techniques. 

5. Each owner or operator of an aerospace manufacturing and/or rework operation shall comply 

with the following housekeeping requirements for any affected cleaning operation. Aqueous 

cleaning solvents and hydrocarbon-based solvents which have a maximum composite vapor 

pressure of 7 mm Hg at 20oC are exempt from these requirements. 

(i) Solvent-laden cloth, paper, or any other absorbent applicators used for cleaning shall be 

placed in bags or other closed containers upon completing their use. These bags and 

containers must be kept closed at all times except when depositing or removing these materials 

from the container. The bags and containers used must be of such a design so as to contain 

the vapors of the cleaning solvent. Cotton-tipped swabs used for very small cleaning operations 

are exempt from this requirement. 

(ii) All fresh and spent cleaning solvents, except semi-aqueous solvent cleaners, used in 

aerospace cleaning operations shall be stored in closed containers. 
Chapter 391-3-1 Rules for Air Quality Control 

(iii) Conduct the handling and transfer of cleaning solvents to or from enclosed systems, vats, 

waste containers, and other cleaning operation equipment that hold or store fresh spent 

cleaning solvents in such a manner that spills are minimized. 

6. Each owner or operator of an aerospace manufacturing and/or rework operation utilizing 

hand-wipe cleaning operations (excluding the cleaning of spray gun equipment performed in 

accordance with section 7) shall comply with one of the following: 

(i) Utilize cleaning solvent solutions that are classified as an aqueous cleaning solvent and/or a 

hydrocarbon-based cleaning solvent with a maximum composite vapor pressure of 7 mm Hg at 

20oC. 

(ii) Utilize cleaning solvent solutions that have a composite vapor pressure of 45 mm Hg or less 

at 20oC. 

7. Each owner or operator of an aerospace manufacturing and/or rework operation shall clean 

all spray guns used in the application of primers, topcoats (including self-priming topcoats), and 

specialty coatings utilizing one or more of the following techniques: 

(i) Enclosed System: Spray guns shall be cleaned in an enclosed system that is closed at all 

times except when inserting or removing the spray gun. Cleaning shall consist of forcing 

cleaning solvent through the gun. If leaks are found, repairs shall be made as soon as 

practicable, but no later than 15 days after the leak was found. If the leak is not repaired by the 

15th day after detection, the cleaning solvent shall be removed and the enclosed cleaner shall 

be shut down until the leak is repaired or its use is permanently discontinued. 

(ii) Nonatomized Cleaning: Spray guns shall be cleaned by placing cleaning solvent in the 

pressure pot and forcing it through the gun with the atomizing cap in place. No atomizing air is 

to be used. The cleaning solvent from the spray gun shall be directed into a vat, drum, or other 

waste container that is closed when not in use. 

(iii) Disassembled Spray Gun Cleaning: Spray guns shall be cleaned by disassembling and 

cleaning the components by hand in a vat, which shall remain closed at all times except in use. 

Alternatively, the components shall be soaked in a vat, which shall remain closed during the 

soaking period and when not inserting or removing components. 

(iv) Atomizing cleaning: Spray guns shall be cleaned by forcing the cleaning solvent through 

the gun and directing the resulting atomized spray into a waste container that is fitted with a 

device designed to capture the atomized cleaning solvent emissions. 

8. Each owner or operator of an aerospace manufacturing and/or rework operation that 

includes a flush cleaning operation shall empty the used cleaning solvents each time aerospace 

parts or assemblies, or components of a coating unit (with the exception of spray guns) are flush 

cleaned into an enclosed container or collection system that is kept closed when not in use or 

into a system with equivalent emission control approved by the Director. Hydrocarbon-based 

solvents which have a maximum composite vapor pressure of 7 mm Hg at 20oC and aqueous 

and semi-aqueous materials are exempt from the requirements of this Section. 
Chapter 391-3-1 Rules for Air Quality Control 

9. The following activities are not regulated by this subsection: 

(i) Research and development; 

(ii) Quality control; 

(iii) Laboratory testing activities; 

(iv) Metal finishing; 

(v) Electrodeposition (except for the electrodeposition of paints); 

(vi) Composites processing (except for cleaning and coating of composite parts or components 

that become part of an aerospace vehicle or component as well as composite tooling that 

comes in contact with such composite parts or components prior to cure); 

(vii) Electronic parts and assemblies (except for cleaning and topcoating of completed 

assemblies); 

(viii) Manufacture of aircraft transparencies; 

(ix) Wastewater treatment operations; 

(x) Regulated activities associated with space vehicles designed to travel beyond the limit of 

the earth’s atmosphere, including but not limited to satellites, space stations, and the space 

shuttle; 

(xi) Maintenance and rework of antique aerospace vehicles and components. 

10. The requirements for primers, topcoats, and chemical milling maskants specified in 

subsections 1.(i), 1.(ii), 1.(iv) and 1.(v) do not apply to the use of low-volume coatings in these 

categories for which the rolling twelve month total of each separate formulation used at a facility 

does not exceed 50 gallons, and the combined rolling twelve-month total of all such primers, 

topcoats, and chemical milling maskants used does not exceed 200 gallons. The requirements 

for specialty coatings specified in subsection 1.(iii) do not apply to the use of low-volume 

specialty coatings for which the rolling twelve month total of each separate specialty coating 

formulation used at a facility does not exceed 50 gallons, and the combined rolling twelve-month 

total of all such specialty coating formulations used does not exceed 200 gallons. Coatings 

exempted under section 9 of this subsection are not included in these 50- and 200- gallon limits. 

11. The following situations are exempt from the requirements of Sections 3 and 4: 

(i) Any situation that normally requires the use of an airbrush or an extension on the spray gun 

to properly reach limited access spaces; 

(ii) The application of any specialty coating; 
Chapter 391-3-1 Rules for Air Quality Control 

(iii) The application of coatings that contain fillers that adversely affect atomization with HVLP 

spray guns and that cannot be applied by any of the application methods specified in 

subparagraph 3.; 

(iv) The application of coatings that normally have a dried film thickness of less than 0.0013 

centimeter (0.0005 inches) and that cannot be applied by any of the application methods 

specified in section 3.; 

(v) The use of airbrush application methods for stenciling, lettering, and other identification 

markings; 

(vi) The use of hand-held spray (aerosol) can application methods; and 

(vii) Touchup and repair operations. 

12. The following cleaning operations are exempt from the requirements of Section 6 of this 

subsection: 

(i) Cleaning during the manufacture, assembly, installation, maintenance, or testing of 

components of breathing oxygen systems that are exposed to the breathing oxygen; 

(ii) Cleaning during the manufacture, assembly, installation, maintenance, or testing of parts, 

subassemblies, or assemblies that are exposed to strong oxidizers or reducers (e.g., nitrogen 

tetroxide, liquid oxygen, or hydrazine); 

(iii) Cleaning and surface activation prior to adhesive bonding; 

(iv) Cleaning of electronic parts and assemblies containing electronic parts; 

(v) Cleaning of aircraft and ground support equipment fluid systems that are exposed to the 

fluid including air-to-air heat exchangers and hydraulic fluid systems; 

(vi) Cleaning of fuel cells, fuel tanks, and confined spaces; 

(vii) Surface cleaning of solar cells, coating optics, and thermal control surfaces; 

(viii) Cleaning during fabrication, assembly, installation, and maintenance of upholstery, 

curtains, carpet, and other textile materials used in the interior of the aircraft; 

(ix) Cleaning of metallic and non-metallic materials used in honeycomb cores during the 

manufacture or maintenance of these cores, and cleaning of the completed cores used in the 

manufacture or maintenance of aerospace vehicles or components; 

(x) Cleaning of aircraft transparencies, polycarbonate, or glass substrates; 

(xi) Cleaning and solvent usage associated with research and development, quality control, and 

laboratory testing; 
Chapter 391-3-1 Rules for Air Quality Control 

(xii) Cleaning operations, using nonflammable liquids, conducted within five feet of energized 

electrical systems. Energized electrical systems means any AC or DC electrical circuit on an 

assembled aircraft once electrical power is connected, including interior passenger and cargo 

areas, wheel wells, and tail sections; and 

(xiii) Cleaning operations identified as essential uses under the Montreal Protocol for which the 

U.S. EPA has allocated essential use allowances or exemptions. 

13. Each owner or operator of an aerospace manufacturing and/or rework operation shall 

submit a monitoring plan to the Division that specifies the applicable operating parameter value, 

or range of values, to ensure ongoing compliance with Subsection 2.(iii) of this subsection. The 

monitoring device shall be installed, calibrated, operated, and maintained in accordance with the 

manufacturer’s specifications. 

14. Each owner or operator of an aerospace manufacturing and/or rework operation utilizing an 

enclosed spray gun cleaner shall visually inspect the seals and all other potential sources of 

leaks at least once per month. Each inspection shall occur while the spray gun cleaner is in 

operation. 

15. Each owner or operator of an aerospace manufacturing and/or rework operation utilizing 

coatings specified in Section 1 shall maintain a current list of coatings that includes the specific 

category, VOC content as applied, and the monthly amount used for each coating. 

16. Each owner or operator of an aerospace manufacturing and/or rework operation utilizing 

cleaning solvents shall maintain the following records: 

(i) Maintain a current list of hand-wipe and flush cleaning solvents with documentation that 

demonstrates that the cleaning solvent complies with one of the composition requirements in 

Section 6.(i) and for semi aqueous cleaning solvent used for flush cleaning. This list shall 

include the annual amount of each applicable solvent used. 

(ii) Maintain a current list of hand-wipe cleaning solvents with their respective vapor pressures 

or, for blended solvents, VOC composite vapor pressures for all vapor pressure compliant handwipe cleaning solvents listed in Section 6.(ii). This list shall include the monthly amount of each 

applicable solvent used. 

(iii) Maintain a current list of all cleaning solvents with a vapor pressure greater than 45 mm Hg 

used in exempt hand-wipe cleaning operations. This list shall identify the applicable 

exemption(s) for each process and include the monthly amount of each applicable solvent used. 

(iv) Maintain a record of all leaks from enclosed gun cleaners, as found during the monthly 

inspection required by subparagraph 14. of this subsection. The record shall include the 

identification of the leaking paint gun cleaner, the date the leak was discovered, and the date 

the leak was repaired. 

17. For the purpose of this subsection, the following definitions shall apply: 

(i) “Ablative coating” means a coating that chars when exposed to open flame or extreme 

temperatures, as would occur during the failure of an engine casing or during aerodynamic 
Chapter 391-3-1 Rules for Air Quality Control 

heating. The ablative char surface serves as an insulative barrier, protecting adjacent 

components from the heat or open flame. 

(ii) “Adhesion promoter” means a very thin coating applied to a substrate to promote wetting 

and form a chemical bond with the subsequently applied material. 

(iii) “Adhesive bonding primer” means a primer applied in a thin film to aerospace components 

for the purpose of corrosion inhibition and increased adhesive bond strength by attachment. 

There are two categories of adhesive bonding primers: primers with a design cure at 250oF or 

below and primers with a design cure above 250oF. 

(iv) “Aerosol coating” means a coating applied by means of a hand-held, pressurized container, 

which is non-refillable or which utilizes non-refillable propellant canisters and which expels an 

adhesive or a coating in a finely divided spray when a valve on the container is depressed. 

(v) “Aerospace facility” means any facility that produces, reworks, or repairs in any amount any 

commercial, civil, or military aerospace vehicle or component. Regulated activities include 

coating, milling, solvent use, and depainting operations. 

(vi) “Aerospace vehicle or component” means any fabricated part, processed part, assembly of 

parts, or completed unit, with the exception of electronic components, of any aircraft. 

(vii) “Aircraft transparency” means the aircraft windshield, canopy, passenger windows, lenses 

and other components which are constructed of transparent materials. 

(viii) “Antichafe coating” means a coating applied to areas of moving aerospace components 

that may rub during normal operations or installation. 

(ix) “Antique aerospace vehicle or component” means an aircraft or component thereof that was 

built at least 30 years ago. An antique aerospace vehicle would not routinely be in commercial 

or military service in the capacity for which it was designed. 

(x) “Aqueous cleaning solvent” means a cleaning solvent in which water is the primary 

ingredient (greater than 80 percent by weight of cleaning solvent solution as applied must be 

water). Detergents, surfactants, and bioenzyme mixtures and nutrients may be combined with 

the water along with a variety of additives such as organic solvents (e.g., high boiling point 

alcohols), builders, saponifiers, inhibitors, emulsifiers, pH buffers, and antifoaming agents. 

Aqueous solutions must have a flash point greater than 93oC (200oF) (as reported by the 

manufacturer) and the solution must be miscible with water. 

(xi) “Bearing coating” means a coating applied to an antifriction bearing, a bearing housing, or 

the area adjacent to such a bearing in order to facilitate bearing function or to protect base 

material from excessive wear. A material shall not be classified as a bearing coating if it can 

also be classified as a dry lubricative material or a solid film lubricant. 

(xii) “Bonding maskant” means a temporary coating used to protect selected areas of 

aerospace parts from strong acid or alkaline solutions during processing for bonding. 
Chapter 391-3-1 Rules for Air Quality Control 

(xiii) “Caulking and smoothing compounds” means semi-solid materials which are applied by 

hand application methods and are used to aerodynamically smooth exterior vehicle surfaces or 

fill cavities such as bolt hole accesses. A material shall not be classified as a caulking and 

smoothing compound if it can be classified as a sealant. 

(xiv) “Chemical agent-resistant coating (CARC)” means an exterior topcoat designed to 

withstand exposure to chemical warfare agents or the decontaminants used on these agents. 

(xv) “Chemical milling maskants” means a coating that is applied directly to aluminum 

components to protect surface areas when chemical milling the component with a Type I or 

Type II etchant. Type I chemical milling maskants are used with a Type I etchant and Type II 

chemical milling maskants are used with a Type II etchant. This definition does not include 

bonding maskants, critical use and line sealer maskants, and seal coat maskants. Additionally, 

maskants that must be used with a combination of Type I or Type II etchants and any of the 

above types of maskants are also not included in this definition. 

(xvi) “Cleaning operation” means collectively spray-gun, hand-wipe, and flush cleaning 

operations. 

(xvii) “Cleaning solvent” means a liquid material used for hand-wipe, spray gun, or flush 

cleaning. This definition does not include solutions that contain no VOCs (i.e., VOC content 

less than 1.0 weight percent). 

(xviii) “Clear coating” means a transparent coating applied over a colored opaque coating, 

metallic substrate, or placard to give improved gloss and protection to the color coat. In some 

cases, a clearcoat refers to any transparent coating without regard to substrate. 

(xix) “Coating” means a material that is applied to the surface of an aerospace vehicle or 

component to form a decorative, protective, or functional solid film, or the solid film itself. 

(xx) “Coating operation” means using a spray booth, tank, or other enclosure or any area, such 

as a hangar, for applying a single type of coating (e.g., primer); using the same spray booth for 

applying another type of coating (e.g., topcoat) constitutes a separate coating operation for 

which compliance determinations are performed separately. 

(xxi) “Coating unit” means a series of one or more coating applicators and any associated 

drying area and/or oven wherein a coating is applied, dried, and/or cured. A coating unit ends at 

the point where the coating is dried or cured, or prior to any subsequent application of a different 

coating. It is not necessary to have an oven or flashoff area to be included in this definition. 

(xxii) “Commercial exterior aerodynamic structure primer” means a primer used on 

aerodynamic components and structures that protrude from the fuselage, such as wings and 

attached components, control surfaces, horizontal stabilizers, vertical fins, wing-to-body fairings, 

antennae, landing gear, and doors, for the purpose of extended corrosion protection and 

enhanced adhesion. 

(xxiii) “Commercial interior adhesive” means materials used in the bonding of passenger cabin 

interior components. These components must meet FAA fireworthiness requirements. 
Chapter 391-3-1 Rules for Air Quality Control 

(xxiv) “Compatible substrate primer” means either compatible epoxy primer or adhesive primer. 

(xxv) “Corrosion prevention compound” means a compound that provides corrosion protection 

by displacing water and penetrating mating surfaces, forming a protective barrier between the 

metal surface and moisture. Coatings containing oils or waxes are excluded from this category. 

(xxvi) “Critical use and line sealer maskant” means a temporary coating, not covered under 

other maskant categories, used to protect selected areas of aerospace parts from strong acid or 

alkaline solutions such as those used in anodizing, plating, chemical milling and processing of 

magnesium, titanium, or high-strength steel, high-precision aluminum chemical milling of deep 

cuts, and aluminum chemical milling of complex shapes. Materials used for repairs or to bridge 

gaps left by scrubbing operations are also included in this category. 

(xxvii) “Cryogenic flexible primer” means a primer designed to provide corrosion resistance, 

flexibility, and adhesion of subsequent coating systems when exposed to loads up to and 

surpassing the yield point of the substrate at cryogenic temperatures (-275oF and below). 

(xxviii) “Cryoprotective coating” means a coating that insulates cryogenic or subcooled surfaces 

to limit propellant boil-off, maintain structural integrity of metallic structures during ascent or 

reentry, and prevent ice formation. 

(xxix) “Cyanoacrylate adhesive” means a fast-setting, single component adhesive that cures at 

room temperature. Also known as “super glue.” 

 

(xxx) “Depainting operation” means the use of a chemical agent, media blasting, or any other 

technique to remove permanent coatings from the outer surface of an aerospace vehicle or 

components. The depainting operation includes washing of the aerospace vehicle or 

component to remove residual stripper, media, or coating residue. 

(xxxi) “Dry lubricative material” means a coating consisting of lauric acid, cetyl alcohol, waxes, 

or other noncross linked resin-bond materials that act as a dry lubricant. 

(xxxii) “Electric or radiation-effect coating” means a coating or coating system engineered to 

interact, through absorption or reflection, with specific regions of the electromagnetic energy 

spectrum, such as the ultraviolet, visible, infrared, or microwave regions. Uses include, but are 

not limited to, lighting strike protection, electromagnetic pulse (EMP) protection, and radar 

avoidance. Coatings that have been designated as “classified” by the Department of Defense 

are exempt. 

(xxxiii) “Electrostatic discharge and electromagnetic interference (EMI) coating” means a 

coating applied to space vehicles, missiles, aircraft radomes, and helicopter blades to disperse 

static energy or reduce electromagnetic interference. 

(xxxiv) “Elevated-temperature Skydrol-resistant commercial primer” means a primer applied 

primarily to commercial-type aircraft that must withstand immersion in phosphate-ester (PE) 

hydraulic fluid (Skydrol 500b or equivalent) at the elevated temperature of 150oF for 1,000 

hours. 
Chapter 391-3-1 Rules for Air Quality Control 

(xxxv) “Epoxy polyamide topcoat” means a coating used where harder films are required or in 

some areas where engraving is accomplished in camouflage colors. 

(xxxvi) “Exempt solvent” means a specified organic compound that has been determined by the 

EPA to have negligible photochemical reactivity and is listed in 40 CFR 51.100 and/or 391-3-1-

.01(llll). 

(xxxvii) “Fire-resistant (interior) coating” means for civilian aircraft, fire-resistant coatings are

used on passenger cabin interior parts that are subject to the FAA fire-worthiness requirements. 

For military aircraft, fire-resistant interior coatings are used on parts that are subject to the 

flammability requirements of MIL-STD-1630A and MIL-A-87721. For space applications, these 

coatings are used on parts that are subject to the flammability requirements of SE-R-0006 and 

SSP 30233. 

(xxxviii) “Flexible primer” means a primer that meets flexibility requirements such as those 

needed for adhesive bond primer fastener heads or on surfaces expected to contain fuel. The 

flexible coating is required because it provides a compatible, flexible substrate over bonded 

sheet rubber and rubber-type coatings as well as a flexible bridge between fasteners, skin, and 

skin-to-skin joints on outer aircraft skins. 

(xxxix) “Flight test coating” means a coating applied to aircraft other than missiles or single-use 

aircraft prior to flight testing to protect the aircraft from corrosion and to provide required 

marking during flight test evaluation. 

(xl) “Flush cleaning” means the removal of contaminants such as dirt, grease, and coatings 

from an aerospace vehicle or component or coating equipment by passing solvent over, into, or 

through the item being cleaned. The solvent may simply be poured into the item cleaned and 

then drained, or be assisted by air or hydraulic pressure, or by pumping. Hand-wipe cleaning 

operations where wiping, scrubbing, mopping, or other hand actions used are not included in 

this definition. 

(xli) “Fuel tank adhesive” means a non-rubber based adhesive used to bond components 

exposed to fuel and which must be compatible with fuel tank coatings. 

(xlii) “Fuel tank coating” means a coating applied to fuel tank components for the purpose of 

corrosion and/or bacterial growth inhibition and to assure sealant adhesion in extreme 

environmental conditions. 

(xliii) “General aviation” means that segment of civil aviation that encompasses all facets of 

aviation except air carriers, commuters, and military. General aviation includes charter and 

corporate-executive transportation, instruction, rental, aerial application, aerial observation, 

business, pleasure, and other special uses. 

(xliv) “General aviation rework facility” means any aerospace facility with the majority of its 

revenues resulting from the reconstruction, repair, maintenance, repainting, conversion, or 

alteration of general aviation aerospace vehicles or components. 
Chapter 391-3-1 Rules for Air Quality Control 

(xlv) “Hand-wipe cleaning operation” means removing contaminants such as dirt, grease, oil, 

and coatings from an aerospace vehicle or component by physically rubbing it with a material 

such as a rag, paper, or cotton swab that has been moistened with a cleaning solvent. 

(xlvi) “High temperature coating” means a coating designed to withstand temperatures of more 

than 350oF. 

(xlvii) “High volume low pressure (HVLP) spray equipment” means spray equipment that is 

used to apply coating by means of a spray gun that operates at 10.0 psig of atomizing air 

pressure or less at the air cap. 

(xlviii) “Hydrocarbon-based cleaning solvent” means a cleaning solvent that is composed of a 

mixture of photochemically reactive hydrocarbons and oxygenated hydrocarbons and have a 

maximum vapor pressure of seven mm Hg at 20oC. These cleaners also contain no hazardous 

air pollutants. 

(il) “Insulation covering” means material that is applied to foam insulation to protect the 

insulation from mechanical or environmental damage.

(l) “Intermediate release coating” means a thin coating applied beneath topcoats to assist in 

removing the topcoats in depainting operations and generally to allow the use of less hazardous 

depainting methods. 

(li) “Lacquer” means a clear or pigmented coating formulated with a nitrocellulose or synthetic 

resin to dry by evaporation without a chemical reaction. Lacquers are resoluble in their original 

solvent. 

(lii) “Leak” means any visible leakage, including misting and clouding. 

(liii) “Metallized epoxy coating” means a coating that contains relatively large quantities of 

metallic pigmentation for appearance and/or added protection. 

(liv) “Mold release” means a coating applied to a mold surface to prevent the molded piece from 

sticking to the mold as it is removed. 

(lv) “Nonstructural adhesive” means an adhesive that bonds nonload bearing aerospace 

components in noncritical applications and is not covered in any other specialty adhesive 

categories. 

(lvi) “Optical antireflection coating” means a coating with a low reflectance in the infrared and 

visible wavelength ranges that is used for antireflection on or near optical and laser hardware. 

(lvii) “Part marking coating” means coatings or inks used to make identifying markings on 

material, components, and/or assemblies. These markings may be either permanent or 

temporary. 

(lviii) “Pretreatment coating” means an organic coating that contains at least 0.5 percent acids 

by weight and is applied directly to metal or composite surfaces provide surface etching, 

corrosion resistance, adhesion, and ease of stripping. 
Chapter 391-3-1 Rules for Air Quality Control 

(lix) “Primer” means the first layer and any subsequent layers of identically formulated coating 

applied to the surface of an aerospace vehicle or component. Primers are typically used for 

corrosion prevention, protection from the environment, functional fluid resistance, and adhesion 

of subsequent coatings. Primers that are defined as specialty coatings are not included under 

this definition. 

(lx) “Rain erosion-resistant coating” means a coating or coating system used to protect leading 

edges of parts such as flaps, stabilizers, radomes, engine inlet nacelles, etc., against erosion 

caused by rain impact during flight. 

(lxi) “Research and development” means an operation whose primary purpose is for research 

and development of new processes and products and that is conducted under the close 

supervision of technically trained personnel and is not involved in the manufacture of final or 

intermediate products for commercial purposes, except in a de minimis manner. 

(lxii) “Rocket motor bonding adhesive” means an adhesive used in rocket motor bonding 

applications. 

(lxiii) “Rocket motor nozzle coating” means a catalyzed epoxy coating system used in elevated 

temperature applications on rocket motor nozzles. 

(lxiv) “Rubber-based adhesive” means a quick setting contact cement that provide a strong, yet 

flexible bond between two mating surfaces that may be of dissimilar materials. 

(lxv) “Scale Inhibitor” means a coating that is applied to the surface of a part prior to thermal 

processing to inhibit the formation of scale. 

(lxvi) “Screen print ink” means an ink used in screen printing processes during fabrication of 

decorative laminates and decals. 

(lxvii) “Sealant” means a material used to prevent the intrusion of water, fuel, air, or other 

liquids or solids from certain areas of aerospace vehicles or components. 

(lxviii) “Seal coat maskant” means an overcoat applied over a maskant to improve abrasion and 

chemical resistance during production operations. 

(lxix) “Self-priming topcoat” means a topcoat that is applied directly to an uncoated aerospace 

vehicle or component for purposes of corrosion prevention, environmental protection, and 

functional fluid resistance. More than one layer of identical coating formulation may be applied 

to the vehicle or component. 

(lxx) “Semi-aqueous cleaning solvent” means a solution in which water is a primary ingredient 

(greater than 60 percent by weight of the solvent solution as applied must be water). 

(lxxi) “Silicone insulation material” means an insulating material applied to exterior metal 

surfaces for protection from high temperatures caused by atmospheric friction or engine 

exhaust. These materials differ from ablative coatings in that they are not “sacrificial.” 
Chapter 391-3-1 Rules for Air Quality Control 

(lxxii) “Solid film lubricant” means a very thin coating consisting of a binder system containing 

as its main pigment material one or more of the following: molybdenum, graphite, 

polytetrafluoroethylene (PTFE), or other solids that act as a dry lubricant between faying 

surfaces. 

(lxxiii) “Specialty coating” means a coating that, even though it meets the definition of a primer, 

topcoat, or self-priming topcoat, has additional performance criteria beyond those of primers, 

topcoats, and self-priming topcoats for specific applications. These performance criteria may 

include, but are not limited to, temperature or fire resistance, substrate compatibility, 

antireflection, temporary protection or marking, sealing, adhesively joining substrates, or 

enhanced corrosion protection. 

(lxxiv) “Specialized function coating” means a coating that fulfills extremely specific engineering 

requirements that are limited in application and are characterized by low volume usage. This 

category excludes coatings covered in other Specialty coating categories. 

(lxxv) “Spray gun” means a device that atomizes a coating or other material and projects the 

particulates or other material onto a substrate. 

(lxxvi) “Structural autoclavable adhesive” means an adhesive used to bond load-carrying 

aerospace components that is cured by heat and pressure in an autoclave. 

(lxxvii) “Structural nonautoclavable adhesive” means an adhesive used to bond load-carrying 

aerospace components that is cured under ambient conditions. 

(lxxviii) “Surface preparation” means the removal of contaminants from the surface of an 

aerospace vehicle or component or the activation or reactivation of the surface in preparation for 

the application of a coating. 

(lxxix) “Temporary protective coating” means a coating applied to provide scratch or corrosion 

protection during manufacturing, storage, or transportation. Two types include peelable 

protective coatings and alkaline removable coatings. These materials are not intended to 

protect against strong acid or alkaline solutions. 

(lxxx) “Thermal control coating” means a coating formulated with specific thermal conductive or 

radiative properties to permit temperature control of the substrate. 

(lxxxi) “Topcoat” means a coating that is applied over a primer on a aerospace vehicle or 

component for appearance, identification, camouflage, or protection. Topcoats that are defined 

as specialty coatings are not included under this definition. 

(lxxxii) “Touch-up and repair coating” means a coating used to cover minor coating 

imperfections appearing after the main coating operation. 

(lxxxiii) “Touch-up and repair operation” means that portion of the coating operation that is the 

incidental application of coating used to cover minor imperfections in the coating finish or to 

achieve complete coverage. This definition includes out-of-sequence or out-of-cycle coating. 
Chapter 391-3-1 Rules for Air Quality Control 

(lxxxiv) “Type I etchant” means a chemical milling etchant that contains varying amounts of 

dissolved sulfur and does not contain amines. 

(lxxxv) “Type II etchant” means a chemical milling etchant that is a strong sodium hydroxide 

solution containing amines. 

(lxxxvi) “Wet fastener installation coating” means a primer or sealant applied by dipping, 

brushing, or daubing to fasteners that are installed before the coating is cured. 

(lxxxvii) “Wing coating” means a corrosion-resistant topcoat that is resilient enough to withstand 

the flexing of the wings. 

18. Applicability. 

(i) The requirements of this subsection shall apply to all aerospace facilities with potential 

emissions of volatile organic compounds exceeding 100 tons per year, except in the counties of 

Cherokee, Clayton, Cobb, Coweta, DeKalb, Douglas, Fayette, Forsyth, Fulton, Gwinnett, Henry, 

Paulding, and Rockdale, where facilities with potential emissions of volatile organic compounds 

exceeding 25 tons per year are subject to this subsection. 

(ii) Effective January 1, 2015, the requirements of this subsection shall apply to all aerospace 

facilities with potential emissions of volatile organic compounds exceeding 25 tons per year in 

Barrow, Bartow, Carroll, Hall, Newton, Spalding, or Walton County. The requirements of this 

subparagraph (ii) will no longer be applicable if the counties specified in this subparagraph (ii) 

are re-designated to attainment for the 1997 National Ambient Air Quality Standard for ozone 

prior to January 1, 2015. In the event the 1997 National Ambient Air Quality Standard for ozone 

is violated in these counties or the counties specified in subparagraph (i) above, the 

requirements of this subparagraph (ii) will only be reinstated if the Director determines that the 

measure is necessary to meet the requirements of the contingency plan. 

19. Compliance Dates. 

(i) All aerospace facilities subject to this subsection and located in the counties of Cherokee, 

Clayton, Cobb, Coweta, DeKalb, Douglas, Fayette, Forsyth, Fulton, Gwinnett, Henry, Paulding 

and Rockdale shall be in compliance. 

(ii) All aerospace facilities subject to this subsection; located outside Cherokee, Clayton, Cobb, 

Coweta, DeKalb, Douglas, Fayette, Forsyth, Fulton, Gwinnett, Henry, Paulding and Rockdale 

counties; and in operation on or before October 1, 1999, shall be in compliance by January 1, 

2001. 

(iii) All aerospace facilities subject to this subsection; located outside Cherokee, Clayton, Cobb, 

Coweta, DeKalb, Douglas, Fayette, Forsyth, Fulton, Gwinnett, Henry, Paulding and Rockdale 

counties; and which begin initial operation after October 1, 1999, shall be in compliance upon 

startup. 

Authority: O.C.G.A. Section 12-9-1 et seq., as amended.