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Rule 3.20 WOOD PRODUCTS COATING OPERATIONS

(Adopted 12/05/2005, Amended 8/1/2011)

A. GENERAL

A.1 PURPOSE: To establish limits on the emission of volatile organic 

compounds (VOC) from coatings and strippers used on wood 

products.

A.2 APPLICABILITY: This rule applies to any person who uses, 

manufactures, blends, sells, repackages, distributes, or 

specifies the use of wood products coatings and/or strippers for 

use within the District.

A.3 SEVERABILITY: If a court of competent jurisdiction issues an 

order that any provision of this Rule is invalid, it is the 

intent of the District that other provisions of this Rule remain 

in full force and effect, to the extent allowed by law.

B. EXEMPTIONS

B.1 The provisions of this Rule shall not apply to the following:

a. This rule does not apply to sources using less than 55 

gallons per year (singly or in any combination) of wood 

products coatings and/or strippers.

b. Wood products coatings that are sold in non-refillable 

aerosol-spray containers.

c. Coating operations for the purpose of manufacturing a 

finished wood panel intended for attachment to the inside 

walls of buildings including, but not limited to, homes and 

office buildings, mobile homes, trailers, prefabricated 

buildings and similar structures; or a finished exterior wood 

siding intended for use in construction.

d. Coating of architectural components or structures not coated 

in a shop environment. Coating of architectural components 

or structures is subject to the provisions of Rule 3.15 

Architectural Coatings.

e. Stencil coatings when used to comply with U.S. Military 

Specifications.
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C. DEFINITIONS

C.1 Aerosol-Spray Container: Any hand-held, pressurized, nonrefillable container of 1 liter (1.1 quarts) or less where the 

contents are released when a valve on the container is 

depressed.

C.2 Air Assisted Airless Spray: Equipment used to apply coatings 

that uses fluid air pressure to atomize coating and air pressure 

between 0.1 and 50 psig to adjust the spray pattern.

C.3 Binders: Non-volatile polymeric organic materials (resins) that 

form the surface film in coating applications.

C.4 Capture Efficiency: Expressed in percent, capture efficiency is 

the ratio of the weight of the VOC in the effluent stream 

entering a control device to the weight of the VOC emitted from 

wood product coating operations, both measured simultaneously, 

and can be calculated by the following equation:

Where: Wc = Weight of VOC entering the control device

We = Weight of VOC emitted

C.5 Clear Topcoat: A final coating that contains binders, but not 

opaque pigments, and is specially formulated to form a 

transparent or translucent solid protective film.

C.6 Closed Container: A container that has a cover where the cover 

meets with the main body of the container without any gaps 

between the cover and the main body of the container.

C.7 Coating: A material which is applied to a surface and which 

forms a film in order to beautify and/or protect such surface. 

"Coating" includes, but is not limited to, materials such as 

topcoats, stains, sealers, fillers, conversion varnish, 

pigmented coatings, multicolored coatings, moldseal coatings, 

washcoats, and toners.

C.8 Control Efficiency: Expressed in percent, control efficiency is 

the ratio of the weight of the VOC removed by the control device 

from the effluent stream entering the control device to the 

weight of VOC in the effluent stream entering the control 

device, both measured simultaneously. Control efficiency is

calculated by the following equation:
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 Where: Wc = Weight of VOC entering the control device

Wa = Weight of VOC discharged from the control device

C.9 Conversion Varnish: A coating comprised of a homogeneous (alkydamino resin) liquid which, when acid catalyzed and applied, 

hardens upon exposure to air or heat by evaporation and 

polymerization to form a continuous film that imparts protective 

or decorative properties to wood surfaces. Any conversion 

varnish used as a self sealing system shall be classified as a 

conversion varnish rather than a sealer.

C.10 Dip Coat: A coating which is applied by dipping an object into a 

vat of coating material and allowing any excess coating material 

to drain off.

C.11 Electrostatic Application: The electrical charging of atomized 

coating droplets for deposition by electrostatic attraction.

C.12 Exempt Compound: As defined in District Rule 1.1, Definitions.

C.13 Filler: A preparation used to fill in cracks, grains, etc. of 

wood before applying a coating. 

C.14 Flow Coat: A coating of which is applied by flowing a stream of 

coating over an object and allowing any excess coating material 

to drain off.

C.15 High-Solid Stain: Stains containing more than 454 grams (1 

pound) of solids per 3.785 liters (1 gallon), by weight and can 

include wiping stains, glazes, and opaque stains.

C.16 High-Volume, Low-Pressure (HVLP): Equipment used to apply 

coatings by means of a gun which is designed to be operated and 

which is operated between 0.1 and 10 pounds per square inch 

gauge (psig) air pressure measured dynamically at the center of 

the air cap and at the air horns.

C.17 Ink: A fluid that contains dyes and/or colorants and is used to 

make markings but not to protect surfaces.

C.18 Low-Solids Stains: Stains that contain 454 grams (1 pound) or 

less of solids per 3.785 liters (1 gallon) or less by weight.

C.19 Low-Volume, Low-Pressure (LVLP) Equipment: Spray coating 

application equipment with air pressure between 0.1 and 10.0 

psig and air volume less than 15.5 cubic feet per minute (cfm) 

per spray gun and which operates at a maximum fluid delivery 

pressure of 50 psig.
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C.20 Mold-Seal Coating: The initial coating applied to a new mold or 

repaired mold to provide a smooth surface which, when coated 

with a mold release coating, prevents products from sticking to 

the mold.

C.21 Multi-Colored Coating: A coating which exhibits more than one 

color when applied and which is packaged in a single container 

and applied in a single coat.

C.22 New Wood Product: A wood product which has not been previously 

coated. A wood product from which uncured coatings have been 

removed to repair flaws in initial coatings applications is a 

new wood product.

C.23 Pigmented Coatings: Opaque coatings that contain binders and 

colored pigments that are formulated to hide the wood surface 

either as an undercoat or topcoat.

C.24 Reactive Diluents: A liquid component of a coating that is a VOC 

during application, and one in which through chemical or 

physical reactions, such as polymerization, becomes an integral 

part of a finished coating.

C.25 Refinishing Operation: The steps necessary to remove cured 

coatings and to repair, preserve, or restore a wood product.

C.26 Repair Coating: A coating used to recoat portions of a product 

which has sustained mechanical damage to the coating following 

normal coating operations.

C.27 Roll Coater: A series of mechanical rollers that form a thin 

coating film on the surface of the roller which is applied to a 

substrate by moving the substrate underneath the roller.

C.28 Sealer: A coating containing binders which seals the wood prior 

to application of subsequent coatings.

C.29 Stencil Coating: An ink or a pigmented coating which is rolled 

or brushed onto a template or stamp in order to add identifying 

letters and/or numbers to wood products.

C.30 Stripper: A liquid used to remove cured coatings, cured inks, 

and/or cured adhesives.

C.31 Surface Preparation and Clean-up: The removal of loosely held 

uncured adhesives, uncured inks, uncured coatings, and 

contaminants such as dust, soil, oil, grease, etc., at any step 

in the production, repair, maintenance, or servicing of parts, 
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products, tools, machinery, equipment, or general work areas and 

including the storage and disposal of VOC containing materials.

C.32 Toner: A wash coat which contains binders and dyes or pigments 

to add tint to a coated surface.

C.33 Touch-up Coating: A coating used to cover minor coating 

imperfections appearing after the main coating operation.

C.34 Volatile Organic Compound (VOC): As defined in District Rule 

1.1.

C.35 Volatile Organic Compound Composite Partial Vapor Pressure: The 

sum of the partial pressures of compounds defined as VOC.

C.36 Wash Coat: A coating that is used to seal wood surfaces, 

preventing undesired staining, and control penetration. For the 

purpose of this rule, wash coats shall be considered low-solids 

coatings and shall contain less than 454 grams (1 pound) of

solids per 3.785 liters (1 gallon) by weight. Wash coats with 

greater than 454 grams (1 pound) of solids per 3.785 liters (1 

gallon), by weight, shall be considered sealers.

C.37 Wood Panel: Any piece of wood or wood composition which is solid 

or laminated, and which is larger than 10 square feet in size, 

and which is not subsequently cut into smaller pieces.

C.38 Wood Products: Surface-coated products which include cabinets 

(kitchen, bath, and vanity), tables, chairs, beds, sofas, 

shutters, art objects, and any other coated objects made of 

solid wood and/or wood composition.

C.39 Wood Product Coating Application Operations: A combination of 

coating application steps of which may include use of spray 

guns, flash-off areas, spray booths, ovens, conveyors, and/or 

other equipment operated for the purpose of applying coating 

materials.

D. REQUIREMENTS

D.1 Application Equipment Requirements: A person subject to the 

provisions of this rule shall not apply any wood products 

coating to any wood products, unless one of the following 

application methods is used:

a. Electrostatic application equipment;

b. High Volume Low Pressure spray equipment;

c. Low-Volume, Low-Pressure spray equipment;
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d. Air assisted airless, for touch-up and repair only;

e. Hand application methods, such as brushes or rollers;

f. Dip coat;

g. Flow coat;

h. Roll coat;

i. Vacuum coat;

j. Any other equivalent method, which has been approved in 

writing by the Air Pollution Control Officer (APCO) and the 

U.S. Environmental Protection Agency (EPA).

D.2 VOC Content of Coatings for New Wood Products: Except as 

provided in Sections D.5 and D.6 of this rule, no person shall 

apply any coating to a new wood product which has a volatile

organic compound (VOC) content exceeding the applicable limits 

specified below:

Coating Category

VOC limits

Less water and exempt compounds

Grams per liter lb-VOC/lb-solid

Clear Topcoats 275 0.35

Conversion 550 1.20

Filler 275 0.18

High-Solid Stain 350 0.42

Inks 500 0.96

Mold-Seal Coating 750 4.20

Multi-Colored Coating 275 0.33

Pigmented Coating 275 0.25

Sealer 275 0.36

Coating Category

VOC limits

Grams per liter lbs./gal.

Low-Solid Stains, 

Toners, Wash coats 120 1.00

a. Notwithstanding the VOC limits specified in this section, a 

person may apply a sealer with a VOC content not exceeding 

680 grams/liter, provided that the topcoat used on the same 

wood product does not exceed 275 grams/liter.

b. If emission averaging is not used to achieve compliance with 

this section, VOC limits expressed in grams per liter shall 

be used.

c. If emission averaging is used to achieve compliance with this 

section, VOC limits expressed in pounds of VOC per pound of 

solids shall be used.
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D.3 VOC Content of Coatings for Refinishing, Repairing, Preserving, 

or Restoring Wood Products: Except as provided in Sections D.5

and D.6 of this rule, no person shall apply any coating to 

refinish, repair, preserve, or restore a wood product which has 

volatile organic compound (VOC) content exceeding the applicable 

limits specified below:

Coating Category

VOC limits

Less water and exempt compounds

Grams per liter lb-VOC/lb-solid

Clear Topcoats 680 2.50

Conversion 550 1.20

Filler 500 0.96

High-Solid Stain 700 2.57

Inks 500 0.96

Mold-Seal Coating 750 4.20

Multi-Colored Coating 680 2.60

Pigmented Coating 600 1.60

Sealer 680 2.50

Coating Category VOC limits

Grams per liter lbs./gal.

Low-Solid Stains, 

Toners, Wash coats 480 4.00

a. If emission averaging is not used to achieve compliance with 

this section, VOC limits expressed in grams per liter shall 

be used.

b. If emission averaging is used to achieve compliance with this 

section, VOC expressed in pounds of VOC per pound of solids 

shall be used.

D.4 VOC Content For Strippers: A person shall not use a stripper on 

wood products unless:

a. It contains less than 350 grams of VOC per liter of material; 

or

b. The VOC composite partial vapor pressure is 2 mm Hg (0.04 

psig) or less at 20oC (68oF), as calculated pursuant to 

Section G.9 of this rule.

D.5 Emission Control Equipment: As an alternative, a person may 

comply with the VOC limits specified in Sections D.2, D.3, and 

D.4. of this rule by using an approved air pollution control 

system consisting of all the following:
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a. A capture and control device which reduces VOC emissions from 

the application of wood products coatings or strippers by an 

equivalent or greater amount than the limits specified in 

Sections D.2, D.3, and D.4 of this rule, with written 

approval of the Air Pollution Control Officer (APCO). The 

minimum required overall capture and control efficiency of an 

emission system at which an equivalent or greater level of 

VOC reduction will be achieved shall be calculated by the 

following equation:

Where: C.E.= Overall Control Efficiency, percent.

VOCLWc = VOC Limit of Rule 3.20, less water and 

less exempt compounds, pursuant to 

Sections D.2, D.3, and/or D.4

VOCLWn,Max = Maximum VOC content of non-compliant 

coating used in conjunction with a 

control device, less water and less 

exempt compounds.

Dn,Max = Density of solvent, reducer, or thinner 

contained in the non-compliant coating, 

containing the maximum VOC content of the 

multi-component coating.

Dc = Density of corresponding solvent, 

reducer, or thinner used in the compliant 

coating system = 880 g/L

b. The capture system shall vent all drying oven exhaust to the 

control device and shall have one or more inlets for 

collection of fugitive emissions;

c. During any period of operation of a thermal incinerator, 

combustion temperature shall be continuously monitored;

d. During any period of operation of a catalytic incinerator, 

exhaust gas temperature shall be continuously monitored;

e. Written approval for the use of such equipment is obtained 

from the Air Pollution Control Officer (APCO) prior to 

installation or use of the equipment.

D.6 Emissions Averaging Provisions: A person may comply with the 

provisions of Sections D.2, D.3, and D.4 of this rule by using 

an averaging approach for all or a portion of the coatings used 
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at the facility, provided that all the following requirements of 

are met:

a. A person shall demonstrate that the emissions from the 

coatings being averaged, on a pounds of VOC per pounds of 

solids basis on a rolling 30-day basis, are less than or 

equal to the allowable emissions, based on the following:

Where: VOCi = VOC content limit of coating “i” (grams 

of VOC per liter of material for low 

solids coatings and pounds of VOC per 

pound of solids for all other coatings, 

as required in Sections D.2, D.3, or 

D.4 of this rule.)

Ui = Usage of coating “i” (liters of 

material for low solids coatings, and 

pounds of solids for all other 

coatings), and

ERi = Actual VOC content of coating “i”, as

applied (grams per liter for low solids 

materials and pounds of VOC per pounds 

of solids for all other coatings).

b. Any wood product coating not included in emissions averaging 

shall comply with the VOC limits in Sections D.2, D.3, or D.4 

of this rule.

D.7 Requirements for Surface Preparation and Clean-up Materials: 

Any solvent cleaning of application equipment, parts, products, 

tools, machinery, equipment, general work areas, and the storage 

and disposal of VOC-containing materials used in surface 

preparation and clean-up operations shall be carried out 

pursuant to District Rule 3.14, Surface Preparation and Cleanup.

D.8 Storage and Disposal – General Requirements: All VOC-containing 

materials, whether in its form for intended use or as a waste or 

used product, including items such as cloth or paper laden with 

VOC containing materials, shall be stored in non-absorbent, nonleaking containers which shall be kept closed at all times, 

except when filling or emptying, and disposed of in a manner to 

prevent evaporation of VOCs into the atmosphere at the facility.
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E. ADMINISTRATIVE REQUIREMENTS

E.1 Labeling Requirements - VOC content: Each container of any 

coating or stripper manufactured after date of adoption shall 

display its maximum VOC content of the coating, as applied, and 

after any thinning as recommended by the manufacturer, or shall 

have this information provided in a product data sheet supplied 

with the container. VOC content shall be displayed as grams of 

VOC per liter of coating (less water and less exempt solvent, 

and excluding any colorant added to tint bases) or stripper. VOC 

content displayed may be calculated using product formulation 

data, or may be determined using the test method in Section G of 

this rule. Alternatively, containers for strippers subject to 

the provisions of Section D.4 of this rule may display only the 

partial vapor pressure.

E.2 Operation and Maintenance Plan (“O&M Plan”): Any person using an 

approved emission control device pursuant to Section D.5 as a 

means of complying with this rule must submit an O&M Plan for 

the emission control device to the Air Pollution Control Officer

for approval. Each O&M Plan shall specify operation and

maintenance that will demonstrate continuous operation of the 

emission control device during periods of emissions-producing 

operations. Each O&M Plan shall also specify which records must 

be kept to document these operations and maintenance procedures. 

An O&M Plan shall be implemented upon approval of the Air 

Pollution Control Officer.

E.3 Emissions Averaging Plan (“EA Plan”): A person wanting to use 

emissions averaging to achieve compliance with this rule 

pursuant to D.6 shall submit an Emissions Averaging Plan for 

approval by the Air Pollution Control Officer. The EA Plan may 

not be implemented until approved in writing, by the Air 

Pollution Control Officer. Submittal of an EA Plan does not 

provide an exemption from the requirements of this rule. If the 

EA Plan is not approved, emissions averaging will not be 

permitted. The EA Plan shall include, at a minimum:

a. A description of the wood product coatings to be included in 

the averaging program; and

b. A description of the quantification and recordkeeping for 

coating usage, coating VOC and solids content, VOC emissions, 

and calculations to show compliance with Section D.6 of this 

rule.
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F. MONITORING AND RECORDS:

F.1 Usage Records: Any person subject to this Rule shall maintain 

the following records in order to evaluate compliance:

a. A data sheet, material list, or invoice giving material name, 

manufacturer identification, material application, and VOC 

content;

b. Any catalysts, reducers, or other components used and the mix 

ratio; and the applicable VOC limit from Section D.2. or D.3.

and the actual VOC content of the wood product coating as 

applied;

c. For persons using coatings or materials that comply with the 

VOC limits specified in Sections D.2, D.3, and D.4 of this 

rule, records shall be maintained on a monthly basis showing 

the type and volume of coatings and strippers used. Coating 

type shall be designated according to the coating categories 

as listed in Sections D.2, D.3, and D.4;

d. For persons using a collection and control system pursuant to 

Section D.5 of this rule, records shall be maintained on a 

daily basis showing the type and volume of coatings and 

solvents used. Key system operating and maintenance 

procedures of the control system shall also be maintained on 

a daily basis. Key system operating parameters are those 

necessary to ensure compliance with the requirements of 

Section D.5 of this rule.

e. For coatings used in emissions averaging pursuant to Section 

D.6 of this rule, daily records shall be maintained showing 

the type and volume of coatings and strippers used;

F.2 Duration of Records: All records required by this rule shall be 

maintained for at least three (3) years, and shall be made 

available to the Air Pollution Control Officer upon request.

G. TEST METHODS AND CALCULATIONS

G.1 General: For the purposes of this Rule, the following test 

methods or calculation methods shall be used. Other test methods 

determined to be equivalent and approved in writing by the 

District and the EPA may also be used. VOC emissions or other 

parameters determined to exceed any limits established by this 

Rule through the use of any of the following test methods or 

calculations shall constitute a violation of this Rule.
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G.2 Determination of VOC Content: VOC content of wood products

coatings, strippers, and surface preparation and clean-up 

materials subject to this rule shall be determined in accordance 

with EPA Method 24 and Section G.10 or G.11 of this rule, as 

applicable.

G.3 Determination of Composition of VOC: The composition of VOC 

shall be as specified on the manufacturer’s label or data sheet, 

or as determined by ASTM Method E-260, General Gas

Chromatograph.

G.4 Determination of Compounds Exempt from VOC Definition: Exempt 

compounds shall be determined in accordance with South Coast Air 

Quality Management District Method 303. If any of the

perfluorocarbons or volatile cyclic and linear methyl siloxanes 

are being claimed as exempt compounds, the person making the 

claim must state in advance which compounds are present, and the 

EPA approved test method used to make the determination of these

compounds.

G.5 Determination of Capture Efficiency: Efficiency of the

collection system shall be determined in accordance with EPA

“Guidelines for Determining Capture Efficiency, January 9, 

1995”. Individual collection efficiency test runs subject to the 

U.S. EPA technical guidelines shall be determined by one of the 

following:

a. Applicable U.S. EPA Methods 204, 204A, 204B, 204C, 204E, 

and/or, 204F; or

b. The South Coast Air Quality Management District “Protocol for 

Determination of Volatile Organic Compound (VOC) Capture 

Efficiency”; or

c. Any other method approved by the U.S. EPA, the California Air 

Resources Board, and the Air Pollution Control Officer.

G.6 Determination of Control Efficiency: Efficiency of control 

equipment shall be determined in accordance with EPA Method 18, 

25, 25A, EPA Method 2 or 2C (whichever is applicable).

G.7 Vapor Pressure: Vapor pressures may be obtained from standard 

reference texts or may be determined by ASTM D-2879.

G.8 Volatile Content of Radiation Curable Materials: Volatile 

content of radiation curable materials shall be obtained in 

accordance with ASTM Method D-5403-93.
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G.9 Calculation for Determining Volatile Organic Compound Composite 

Partial Vapor Pressure: VOC composite partial vapor pressure for 

determination of compliance with Section D.4. of this rule shall 

be calculated by the following equation:

Where: PPc = VOC composite partial presser at 20°C, 

in mmHg.

Wi = Weight of the “i”th VOC compound, in 

grams.

Ww = Weight of water, in grams.

We = Weight of exempt compounds, in grams.

MWi = Molecular weight of the “i”th VOC 

compound, in (g/gmole).

MWw = Molecular weight of water, in 

(g/gmole).

MWe = Molecular weight of exempt compound, in 

(g/gmole).

VPi = Vapor Pressure of the “i”th VOC 

compound at 20°C, in mmHg.

G.10 Calculation For Determining Weight of VOC Per Volume of Coating, 

Less Water and Less Exempt Compounds: The weight of VOC per 

combined volume of VOC and coating solids, shall be calculated 

by the following equation:

Where: Wv = Weight of Volatile Compounds, in grams.

Ww = Weight of water, in grams

Wec = Weight of exempt compounds, in grams.

Vm = Volume of coating material, in liters.

Vw = Volume of water, in liters.

Vec = Volume of exempt compounds, in liters.

G.11 Calculation for Determination of VOC Content per Volume of 

Material: The volume of material is defined as the volume of the 

original material, plus any VOC-containing material added to the

original material. The original material is the material before 

any VOC-containing material such as the solvent is added for 

purposes of mixing or thinning. The VOC content shall exclude 

any colorant added to a tint base. The weight of VOC per total 
Feather River AQMD 3.20 - 14

volume of material shall be calculated by the following 

equation:

Where: Wv = Weight of all Volatile Compounds.

Ww = Weight of water.

Wec = Weight of compounds listed as exempt 

from the definition of VOC as provided 

for in the definition of Exempt 

Compounds in this Rule.

Vm = Volume of material.

G.12 Calculation for Determination of Pounds of VOC per Pound of 

Solids: Pounds of VOC per pound of solids is the weight of VOC 

per weight of coating solids within any given volume of coating, 

and can be calculated by the following equation:

Where: Ws = Weight of all Volatile Compounds, in 

pounds.

Ww = Weight of water, in pounds.

Wec = Weight exempt compounds, in pounds.

Wr = Weight of coating solids, in pounds.

G.13 Calculation for Coatings That Contain Reactive Diluents: For 

coatings that contain reactive diluents, the VOC content of the 

coating is determined after curing. The pounds of VOC per pound 

of coating solids shall be calculated by the test method found 

in Section G and the following equation:

Where: Ws = Weight of Volatile Compounds, in pounds 

emitted into the atmosphere during 

curing.

Ww = Weight of water, in pounds emitted into 

the atmosphere during curing.

Wec = Weight exempt compounds, in pounds 

emitted into the atmosphere during 

curing.

Wr = Weight of coating solids, in pounds 

prior to reaction.