United States Office of Air Quality EPA-450/3-83-013R
Environmental Protection Planning and Standards December 1983
Agency Research Triangle Park NC 27711
Air
Glossary for
Pollution Control
of Industrial
Coating Operations
Second Edition
(With Graphical Aids
for Rapid Estimation
of Acceptable
Compliance Alternatives)
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EPA-450/3-83-013R
Glossary for Air Pollution
Control of Industrial
Coating Operations
Second Edition
(With Graphical Aids for Rapid
Estimations of Acceptable
Compliance Alternatives)
Emission Standards and Engineering Division
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Air, Noise, and Radiation
Office of Air Quality Planning and Standards
Research Triangle Park, North Carolina 2771 1
Region 5, Libr-'T'' r
77 West Js3!;ir •
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This report has been reviewed by the Emission Standards and
Engineering Division of the Office of Air Quality Planning and
Standards, EPA, and approved for publication. Mention of trade names
or commercial products is not intended to constitute endorsement or
recommendation for use. Copies of this report are available through
the Library Services Office (MD-35), U.S. Environmental Protection
Agency, Research Triangle Park, North Carolina 27711; or, for a fee
from the National Technical Information Services, 5285 Port Royal
Road, Springfield, Virginia 22161.
Publication No. EPA-450/3-83-013R
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PREFACE
Since 1977 the U.S. Environmental Protection Agency has issued a
series of guidelines and regulations, the implementation of which
will result in large reductions in air pollution emitted by industrial
coating operations. The guidelines (referred to as Control Technique
Guidelines, or CTG's) are used to apprise the States of reasonably
available control technology for major existing sources of volatile
organic compounds (VOC's). The Federal regulations are applicable to
new or modified sources of pollution and are known as New Source Per-
formance Standards.
This regulatory activity has meant that industries must become
familiar with regulatory terms from the Clean Air Act, and State and
local agencies must learn terminology from the coatings industry.
This glossary is an attempt to aid both groups by listing the most
common terms which will be used by both in the application of air
pollution control to paints and coatings. The goal is for local con-
trol agents and industry representatives to be able to speak a common
language as they try to mutually solve the problems of controlling air
pollution from industrial coatings.
Also included as Appendices are example calculations which illus-
trate important coating concepts. Appendix A illustrates the effect of
changes in coating solids or transfer efficiency on the amount of VOC
which will be emitted from a coating operation. Appendix B contains
two charts which permit rapid manipulation of the various units used to
describe the solvent content of coatings. Figure B-l allows rapid cal-
culation of the solvent content of any of three major types of coatings
when the volume percent solids is known. Figure B-2 allows a quick
estimation of the emission reduction achieved when a coating with lower
solvent content is substituted for one which contains more solvent.
Appendix C provides practical examples of how Figures B-l and B-2 may
be used to determine the possible compliance alternatives available to
a coater.
William Johnson
Chemical Applications Section
Emission Standards and
Engineering Division
iii
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TABLE OF CONTENTS
GLOSSARY OF TERMS Pages 1-23
APPENDIX A - SURFACE COATING EMISSION CALCULATIONS Page 24
APPENDIX B - RAPID CONVERSION AIDS Page 31
APPENDIX C - EXAMPLE OF DETERMINING COMPLIANCE ALTERNATIVES
USING GRAPHICAL AIDS Page 35
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Glossary of Terms
Absorption - The unit operation in which one or more soluble compo-
nents of a gas mixture are dissolved in a liquid.
Add-on control device - An air pollution control device such as carbon
adsorber or incinerator which reduces the pollution in an exhaust
gas. The control device usually does not affect the process being
controlled and thus is "add-on" technology as opposed to a scheme
to control pollution through riaking some alteration to the basic
process.
Affected facility - With reference to a stationary source, any appara-
tus to which a standard is applicable.
Air dry - A coating which dries or cures at ambient temperature.
Air spray - Spray coating method in which the coating is atomized by
mTxTng it with compressed air.
Airless spray - Spray coating method in which the coating is atomized
by forcing it through a small opening at high pressure. The liquid
coating is not mixed with air before exiting from the nozzle.
ALAPCO - Association of Local Air Pollution Control Officials.
Aliphatic compounds - Organic compounds composed of open chains of car-
bon atoms. TFese include paraffins and olefins, but not aromatic
compounds.
Alternative method - Any method of sampling and analyzing for an air
pollutant which is not a reference or equivalent method but which
has been demonstrated to the Administrator's satisfaction to, in
specific cases, produce results adequate for his determination of
compliance.
Anodic electrodeposition - Electrodeposition in which the part being
painted is wired to serve as the anode or electron donor. This
was the first type of electrodeposition developed, but has been
largely replaced by cathodic electrodeposition which qives better
corrosion protection.
Applied solids - Solids which remain on the substrate being coated or
painted.
Architectural coatings - Stock type or shelf coatings which are formu-
lated for service under environmental conditions, and for general
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application on new and existing residential, commercial, institu-
tional, and industrial structures. These are distributed through
wholesale - retail channels and purchased by the general public,
painters, building contractors, and others.
Aromatic solvent - Solvents made of compounds that contain an unsat-
urated ring of carbon atoms, typified by benzene's structure.
Xylene and toluene are aromatic solvents often used in coatings.
Attainment area - An area which is considered to have air quality as
good as or better than the national ambient air quality standards,
as defined by Section 107 of the Clean Air Act. An area may be an
attainment area for one pollutant and a non-attainment area for
others.
Automatic electrostatic spray application - Electrostatic spray applied
by a robot or other self-acting mechanism. Automatic electrostatic
spray can be a very effient way to transfer coatings to the sub-
strate thus reducing pollution which otherwise would result from
wasted paint overspray.
BACT - "Best available control technology" - an emission limitation
based on the maximum degree of emission reduction which (consi-
dering energy, environmental, and economic impacts and other
costs) is achievable through application of production processes
and available methods, systems, and techniques. In no event does
BACT permit emissions in excess of those allowed under any appli-
cable NSPS or NESHAP. It is applicable on a case-by-case basis
for each major new (or modified) emission source to be located
in areas attaining the National Ambient Air Quality Standards.
It applies to each pollutant regulated under the Act, and is
concerned with Prevention of Significant Deterioration (PSD). See
Sections 165(a)(4) and 169 of the Clean Air Act.
Baking temperatures - The recommended temperatures for operation of the
curing oven in which a coated part is baked or cured to obtain op-
timum properties. The amount of volatile material released from
the coating can sometimes increase if baking temperature is
increased.
Banking - A system for recording qualified emission reductions for
later use in bubble, offset, or netting transactions.
Base coat/Clear coat - A two step finish coat system in which a highly
pigmented, often metallic, basecoat is followed by a thicker clear
coat. It reportedly results in a finish with high gloss
characteristics.
Bell - An electrostatic spray device in which the paint applicator is
shaped like a bell. This bell revolves rapidly so that paint,
metered to the center of the bell, is thrown by certifugal force
off of the edge as a fine mist. High electrostatic voltage main-
tained on the bell also contributes to keeping the paint spray
a fine mist. This fine mist allows electrostatic forces to
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draw the paint to the part being coated very efficiently with
verv little overspray. The bell is one of the most efficient
pieces of spray equipment with transfer efficiencies commonly
over 90 percent. When high bell speeds are used (over 30,000
revolutions per minute) then high solids coatings may be sprayed
more easily than with other types of spray equipment.
Beverage can - A can used for soft drinks or beer.
Binder - Nonvolatile portion of the liquid portion of a coating. When
~ - the paint dries, the binder becomes part of the solid film bind-
ing the pigment particles together and cementing the paint film to
the substrate over which it is applied.
Blushing - A film defect appearing as a milky opalescence which some-
times appears as the film or lacquer dries. It is often caused
the rapid solvent evaporation cools the surface and causes
for a comparable relaxation of controls at a second
oint wher^costs are high. The bubble policy, -as ^
in the Federal Register December 11, 1979 (44 FR
changes were proposed on April 7, 1982.
Caoture - The containment or recovery of emissions from a process for
^direction into a duct which may be exhausted through a stack or
sent to a control device. The overall abatement of emissions from
a process with an add-on control device is a function both of the
capture efficiency and of the control device.
Caoture device - A hood, enclosed room, floor sweep or other means of
'collecting solvent or other pollutants into a duct. The pol utant
can then be directed to a pollution control device sue as an^n-
cinerator or carbon adsorber. Sometimes the term is used loosely
to include the control device.
Caoture Efficiency - The fraction of all organic vapors generated by a
^process that are directed to an abatement or recovery device.
Carbon Adsorber - An add-on control device which us« .
s1:
surface on which it was formed.
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Catalytic incinerator - A control device which oxidizes VOC by using a
catalyst to promote the combustion process. The catalyst allows
the combustion process to proceed at a lower temperature (usually
around 600°F to 800°F) than a conventional thermal incinerator
would require (1,100 to 1,400°F), resulting in fuel savings and
lower cost incineration.
Cathodic electrodeposition - An electrodeposition paint application
technique where the part being painted is the cathode. Cathodic
electrodeposition gives superior corrosion resistant coatings and
has largely replaced the older anodic processes. Cathodic
electrodeposition is often used to apply automobile primers.
Cellosolve - Proprietary name for Union Carbide's brand of monoethyl
ether of ethylene glycol, C2H50CH2CH20H, a commonly used solvent
for water borne coatings. It is also their generic name for a
series of ethers of similar type such as methyl cellosolve and
butyl cellosolve.
Cellulosic coating - A coating in which a large portion of the solids
are made up of chemically treated cellulose. Cellulose lacquers
are widely used in the wood furniture industry for topcoats.
Chalking - Formation of a powder on the surface of a paint film caused
by disintegration of the binding due to weathering.
Clean Air Act - The Clean Air Act, as amended, provides the foundation
for EPA"'s efforts to improve air quality. The Clean Air Act,
building on earlier legislation, was passed in 1970, and was a-
mended in 1977.
Clear coat - A transparent coating usually applied over a colored
opaque coat to give improved gloss and protection to the color
coat below. In some cases a clear coat simply refers to any
transparent coating without regard to the substrate.
Chlorinated solvent - An organic solvent which contains chlorine atoms
as part of the molecular structure. For example, methylene chlo-
ride and 1,1,1 - trichloroethane, the most common, are used in
aerosol spray containers and in traffic paint. Certain chlorinat-
ed solvents are exempt from some air pollution regulations because
of their low photochemical reactivity.
Coating - A protective or decorative film applied in a thin layer to a
surface. This term often applies to paints such as lacquers or
enamels, but also is used to refer to films applied to paper,
plastics or foil.
Coating application station - The part of a coating line where the
coating is applied. In a spray operation it is the spray booth
and is distinquished from the flash off area and oven.
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Coating head - The coating applicator in a roll coater, rotogravure
coater or knife coating operation.
Coating solids - The part of the coating which remains after the
coating is dried or cured.
Coil coating - A very efficient metal coating operation in which sheet
metal is unwound from a coil, roller coated and rewound. The me-
tal may then be formed into products such as aluminum siding,
automobile parts or a variety of other items.
Compliance coating - A coating whose volatile organic compound content
H does not exceed that allowed by regulation. Compliance coatings
may be water borne, low solvent (higher solids) or powder.
Comoliance schedule - A negotiated agreement between a pollution source
P and a government agency that specifies dates and procedures by
which a source will reduce emissions and, thereby, comply with a
regulation.
Condensation - A method of solvent recovery in which the vaporized
solvent is liquified generally by cooling.
Control - In the air pollution field, this means the abatement of poll-
^^^Mutants which might be exhausted into the atmosphere. It often
refers to the collection or destruction efficiency of an add-on
device such as an incinerator or carbon adsorber as opposed to
capture of the pollutants into the device.
Control device - Any equipment which reduces the quantity of a pollutant
that is emitted to the air. The device may destroy or secure the
pollutant for subsequent recovery. Examples are incinerators,
carbon adsorbers and condensers.
Control device efficiency - The ratio of the pollution released by a
^control device and the pollution introduced to the control device
expressed as a percentage.
Control Technique Guidelines (CTG) - A series of documents prepared by
EPA to assist States in defining reasonable available control
technology (RACT) for major sources of volatile organic compounds
(VOC) The documents provide information on the economic and
technological feasibility of available techniques; and, in some
cases, suggest limits on VOC emissions.
Cowta11 . small marks of paint applied to wood furniture to give an
antique effect.
Catering - A paint film imperfection which appears as tiny depressions
Tnthe surface.
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Criteria pollutant - A pollutant for which a criteria document has been
issued as described by Section 108 of the Clean Air Act. Criteria
pollutants are nitrogen oxides, sulfur oxides, ozone, particulate
matter, and carbon monoxide. A National Ambient Air Quality
Standards (NAAQS) exists for each criteria pollutant.
CTG - A Control Technique Guideline.
Cure volatiles - Reaction products which are emitted during the chemi-
cal reaction which takes place in some coating films at the cure
temperature. These emissions are other than those from the
solvents in the coating.
Curing oven - A heating chamber where wet paint solidifies either
by drying or by chemical cross linking of the paint film.
Designated pollutant - A pollutant which is not a criteria pollutant
(as described in Section 108 of the Clean Air Act) nor a hazardous
air pollutant (as defined in Section 112 of the Clean Air Act) but
for which new source performance standards exist. States are re-
quired to control these pollutants under Section Hid of the Clean
Air Act. Designated pollutants are acid mist, total reduced sulfur
(TRS), and fluorides.
Disk - An electrostatic spray application device which consists of a
rapidly spinning metal disk onto which paint is fed. The paint is
slung off the edge of the rotating disk by centrifugal force and
the paint is formed into a fine mist. This device applies paint
with high transfer efficiency.
Distress - A mechanical deforming of the surface of a piece of wood
fuTniture during the coating process to give an antique appearance.
Dip coating - Method of applying a coating in which the substrate is
dipped into a tank of coating and then withdrawn.
Doctor blade - Method of applying a coating in which a flat metal strip
or blade is mounted such that it scrapes off excess coating from a
roll or rotogravure coater before the coater contacts the paper or
other substrate being coated.
EDP - See Electrodeposition.
Elastomer - A natural or synthetic polymer which has rubber-like
properties.
Electrocoat - See Electrodeposition.
Electrodeposition - Dip coating method in which an electrical field is
used to promote the deposition of the coating material onto the
part. The part being painted acts as an electrode which is oppo-
sitely changed from the particles of paint in the dip tank.
Electron beam - A method of curing coatings which uses high energy
radiation to cross-link polymers.
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Electrostatic spray - A method of applying a spray coating in which op-
posite electrical charges are applied to the substrate and the
coating. The coating is attracted to the object by the electro-
static potential between them.
Elpo - See Electrodeposition.
Emission reduction - The decrease in VOC emitted when (1) a low solvent
coating is used in place of a higher solvent coating or (2) an
add-on control device (such as carbon adsorber or incinerator) is
used on a process. Emission reduction is often expressed as a
percentage. Figure B-2 in Appendex B allows rapid estimation of
the percent reduction when one coating is substituted for another.
Emulsion - A two phase liquid system in which small droplets of one
1iquid are uniformly dispersed throughout the second.
Enamel - A coating that cures by chemical cross-linking of its base re-
sin. Enamels can be readily distinguished from lacquers because
enamels are not resoluble in their original solvent.
End sealing compound - A viscous coating used to form a seal or
gasket between the end of a can and the can body.
Equivalent method - Any method of sampling and analyzing for an air
pollutant which has been demonstrated to the Administrator's satis-
faction to have a consistent and quantitatively known relationship
to the reference method, under specific conditions.
Exempt solvent - Specified organic compounds that are not subject to
the requirements of a regulation. Such solvents that have been
deemed of negligible photochemical reactivity by EPA are: meth-
ane, ethane, 1,1,1-trichloroethane (methyl chloroform), methylene
chloride, trichl orof1uoromethane (CFC-11), dichlorodifluoromethane
(CFC-12), chlorbdifluoromethane (CFC22), trifluoromethane (FC-23),
trichlorotrifluoroethane (CFC-113), dichlorotetraf1uoroethane
(CFC-114), and chloropentafluoroethane (CFC-115).
Existing source - Any stationary source of air pollution other than a
new source.
Exterior basecoat - A coating applied to the outside of a beverage can
toprovide both corrosion resistance and as a background for
lithography or printing.
Face velocity - The velocity of air through a oaint spray booth. Where
people are working, health regulations usually require this velo-
city to be at least 100 feet per minute. When electrostatic spray-
ing is used a face velocity of 60 feet per minute is permitted.
Fabric coating - A process which applies a uniform layer of polymeric
resin on a supporting fabric substrate. Typical coatings are
rubbers, urethanes, vinyls, and acrylics.
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Fabric printing - A process which applies a decorative, usually multi-
colored pattern on a fabric substrate.
Filler - A thick coating applied to wood furniture to fill large pores
in the wood.
Film former - The part of a coating that remains on the substrate after
the cure. Some film formers may be liquid but polymerize to form
a solid when the coating is baked to the requisite curing
temperature.
Film thickness - The thickness of the dry cured coating on the sub-
strate. Film thickness varies with application, but coatings on
metal generally range from 0.5 to 4 mils.
Flashoff zone - The area within a plant where solvents evaporate from a
coating during the interval between coats or before the painted
object enters a bake oven.
Flat screen printer - A semi continuous process for printing on fabric.
The fabric is placed on a belt, the belt and fabric are moved into
position under the flat screen, and the belt is stopped. The flat
screen, on which print paste has been applied is mechanically low-
ered onto the fabric. A squeegee moves across the screen forcing
print paste through a pattern onto the fabric. The screen is then
raised and the fabrics and belt are indexed to the next position
to receive another screen and another color on the pattern.
Flexible packaging - Use of paper, aluminum foil, cellophane or plastic
films either singly or in combination to produce bags, pouches,
and wraps for consumer and industrial products. The flexible
package will typically be less than 50 micrometers (0.002 inches)
thick and will usually conform to the shape of the item(s) it con-
tains.
Flexible vinyl products - Those products composed of a supported
ornonsupportedvinyl sheet or coating and more than 50 micro-
meters (0.002 inches) thick. This term does not. include vinyl
resilient floor coverings.
Flexography - A method of printing in which the image areas are raised
above the non-image areas. The image carrier is made of rubber or
other elastomeric material.
Floor sweep - A vapor collection duct designed to capture vapors which
are heavier than air and which collect along the floor.
Flow coat - Method of applying coating to an object in which the
coating is poured on the object.
Fluidized bed coating - A powder coating technique in which the powder
is applied by lowering the part to be coated into a fluidized con-
tainer of powder. The powder is "fluidized" by blowing air through
the powder from the bottom of the container.
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Fly speck - Small spots of paint that are sprayed onto wood furniture
to creatp an antique affect.
Freedom of information request - A request for information from a
Federal government agency pursuant to the Freedom of Information
Act.
Fugitive emissions - Emissions not caught by a capture system.
General provisions - Suhpart A of part 60 - Standard of Performance for
MewStationary Sources in 40 CFR 60. This subpart contains in-
structions on monitoring and recordkeeping and definitions of
terms generally used in the program for development of new source
performance standards.
Glaze - Small amount of color coating added to wood furniture to high-
light and give character to the wood. These are often manually
wiped to remove most of the color.
Gloss - A property of paints and enamels which can be characterized by
measuring the specular reflectance of the film using ASTM test
D 523-67 (1972) Test for Specular Gloss. The 60-degree specular
gloss test is usedfor allexcept flat paints. A measure-
ment of 65 or more characterize the material as "gloss".
Semi gloss paints are those with readings between about 30 to
65; "flats" when tested at an 85 degree angle have readinqs below
15.
Grain raising - Swelling of the fibers of wood caused by absorbed li-
quids, especially water. Grain raising causes the surface of wood
to look and feel rough.
Handheld electrostatic - A hand held spray gun which uses electrosta-
ticstoimprove efficiency. This application gives higher
transfer efficiency than nonelectrostatic hand held spray.
Hazardous pollutant - An air pollutant to which no ambient air quality
standard is applicable and which causes or contributes to air pol-
lution which may reasonably be anticipated to result in an
increase in serious irreversible or incapacitating reversible,
illness. This definition is given in Section 112 of the Clean Air
Act. Hazardous pollutants include asbestos, mercury, beryllium,
benzene, arsenic, vinyl chloride and radionuclides.
Higher-solids coatings - Paints containing considerably higher solids
than has been conventional in the past. Usually paints with great-
er than 60 percent solids by volume are considered higher solids
coatings although the term is often applied to any coating which
meets any of EPA's Control Technique Guidelines. Formerly, under
California's Rule 66, a high solids paint is one containing not
less than BO percent solids by volume.
Hood - A partial enclosure or canopy for capturing and exhausting, by
means of a draft, the organic vapors or other fumes rising from a
coating process or other source.
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Hood capture efficiency - The emissions from a process which are cap-
tured by the hood and directed into the control device, expressed
as a percent of all emissions.
Hot melt adhesive - Adhesive which is applied in a molten condition and
cools rapidly to form a solid. Hot melt adhesives contain little
or no volatile organic solvents.
Hydrocarbon - An organic compound consisting only of carbon and hydro-
gen. Sometimes the term hydrocarbon is used loosely (but
incorrectly) to refer to any organic compound.
Infrared (I. R.) - Electromagnetic radiation of wave lengths between
0.78 and 1.0 micrometer (780 to 1000 nanometer) sometimes used to
cure coatings.
Inside spray - Coating applied (sprayed) on the inside of cans to
provide a protective film between the contents of the can and the
can body.
Isocyanate - A compound containing the functional group, -N=C=0. These
functional groups may be crosslinked with a hydroxy'l containing
material to form urethane polymers which are often used in
coatings.
Knife coater - A coater used primarily for paper or fabric webs which
employs an adjustable blade or "knife" to distribute a liquid
coating evenly over a moving web surface.
LAER - "Lowest achievable emission rate" - Pursuant to Section 171(1)
of the Clean Air Act, LAER is that rate of emissions which re-
flects:
(a) the most stringent emission limitation which is contained
in the implementation plan of any State for such class or category
of sources, unless the owner or operator of the proposed source
demonstrates that such limitations are not achievable; or
(b) the most stringent emission limitation which is achieved
in practice by such class or category of source, whichever is more
stringent.
In no event, however, shall the application of this term permit a
proposed new or modified source to emit any pollutant in excess of
the amount allowable under applicable new source standards of
performance. Areas of the country that have not attained national
ambient air quality standards may require LAER on new sources of
pollution.
Lacquer - A coating which dries primarily by solvent evaporation, and
hence is resoluble in its original solvent.
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Lamination - The process of adhering two web surfaces together to form
a single composite material. Paper, fabric, foil and plastic film
may be laminated to each other.
Latex - A dispersion of rubber, synthetic resin or polymers used in
paints, adhesives, or coatings.
LEL - See lower explosive limit.
LEL Meter - A device used to measure the concentration of combustible
vapors in an air sample.
Less water - A term used by the Environmental Protection Agency in its
series of Guidelines to the States on development of regulations
for the coating industry and subsequently adopted by many States
in their regulations. The term usually appears in the expression
"pounds of volatile organic compound per gallon of coating (less
water)".
Letter press - A method of printing in which the image areas are raised
above the background area. The mechanism which transfers the
image is made of metal or other relatively hard material.
Lithography - See off-set lithography.
Lower Explosive Limit - (LEL) - The concentration of a compound in air
below which a flame will not propagate if the mixture is ignited.
Low-solvent coating - A coating which contains a lower amount of
volatile organic compound (VOC) than conventional organic solvent
borne coatings. Low solvent coatings usually fall into the three
major groups of higher solids, waterborne or powder coatings.
Magnet wire - Wire used in equipment such as electrical motors, genera-
tors and transformers. Magnet wire is coated with an elec-
trically insulating varnish or enamel.
Maintenance coatings - Coatings used for bridges, chemical plants and
other heavy duty industrial type applications.
Major modification (with respect to Prevention of Significant Deterio-
ration and New Source Review) - This term is defined as in Section
111 of the Clean Air Act with two changes: (1) includes only
modifications to major stationary sources and (2) provides
significant pollutant increase levels below which a modification is
not considered major. (See Section 111 (a) of the Clean Air Act,
40 CFR 51.24(b)(2), (23); 52.2Kb) (2), (23); and 51.18(j) (vi),
(viii)).
Major stationary source - This term is used to determine the applica-
bility of prevention of significant deterioration (PSD) and nonat-
tainment new source review regulations. In a nonattainment area,
any stationary source that has the potential to emit more than TOO
tons per year is considered a major stationary source. In PSD
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areas, the cut-off level maybe either 100 or 250 tons per year
depending on the type of source. (See Subsection 169 and 302(j)
of the Clean Air Act and 40 CFR Section 51.24(b)(l) 52.21 (b)0)
and 51.18(j)(l)(i)-(vi)).
Make-up air - Fresh air drawn in from outside the plant to replace the
dirty solvent laden air from a coating operation or drying oven
that is exhausted from the building. This make-up air must be
heated in the winter to room temperature or even to oven tempera-
ture, thus accounting for a large energy usage.
Make-up solvent - Portion of solvent required to compensate for the
amount Tost, normally via evaporation, during a manufacturing
process.
Manufacturer's formulation - A list of substances or component parts of
coatings as described by the maker of the coatings. This may be
used, in many cases, to calculate the volatile organic compound
content of a coating.
Marine paint - A coating used on ships or boats.
Material balance - A calculation based on conservation of mass, i.e.,
the amount of material going into a process is equal to the amount
which leaves the process. This relationship is often used to
estimate solvent losses from coating operations.
Metallic paint - Paint containing tiny flecks of aluminum or other me-
tal often used for painting automobiles because of the attractive
appearance of the paint.
Method 18 - An EPA test method which uses gas chromatographic techniques
to measure the concentration of individual volatile organic
compounds in a gas stream.
Method 24 - An EPA reference method to determine density, water content
and total volatile content (water and VOC) of coatings. (40 CFR
Part 60 Appendix A)
Method 25 - An EPA reference method to determine the VOC concentration
of a gas stream. (40 CFR Part 60 Appendix A)
Metric ton - A unit of weight equivalent to 2,204.6 pounds or one mega-
gram (10° grams).
Mini-bell - An electrostatic spray application device using a rapidly
rotating bell to atomize paint. The bell is of small diameter giv-
ing rise to the name mini-bell.
Mil - A unit of length equal to one thousandth of an inch.
Miscellaneous metal parts - As used in the Environmental Protection
Agency'sControlTechnique Guidelines, any metal parts excluding
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those produced in can, coil coating, magnet wire, metal furniture,
and large appliance plants, and also excluding automobile, ship,
and airplane bodies.
Model plant - A description of a typical but theoretical plant used for
developing economic, environmental impact, and energy impact
analyses as support for regulations or regulatory guidelines.
It is an imaginary plant the parameters of which are typical
of existing or future plants. The parameters are used to esti-
mate the cost of incorporating air pollution control technology
as the first step in exploring the economic impact of a potential
NSPS. Such analyses are a fundamental part of the development
of a standard, as recorded in the Background Information
Document.
Modified source - An existing facility in which a physical change in
the facility, or a change in method of operation, increases the
amount of any air pollutant (to which a standard applies) emitted
into the atmosphere by that facility or which results in the emis-
sion of any air pollutant (to which a standard applies) into the
atmosphere not previously emitted.
Monomer - The starting compound for a polymerization reaction.
NAAQS - National Ambient Air Quality Standards are developed by EPA
pursuant to Section 109 of the Clean Air Act. They are standards
which, in the judgement of the Administrator of EPA, must be
attained and maintained in order to protect the public health,
with allowance for an adequate margin of safety. "Secondary" NAAQS
similiarly specify a level necessary to protect the public welfare.
NAAQS exist for nitrogen oxides, sulfur oxides, particulate matter,
ozone and carbon monoxide.
NAPCTAC - "The National Air Pollution Control Techniques Advisory Com-
mTttee", a group constituted pursuant to § 117 of the CAA consist-
ing of representatives from industry, universities, local air pol-
lution control agencies, and environmental groups. The committee
meets at the request of the Agency to assist in the development of
NSPS and NESHAP's.
Naphtha - Any of several hydrocarbon solvents, or their mixtures, which
are derived from petroleum products or coal tar. These may be com-
posed of aliphatic or aromatic compounds.
NESHAP - National Emission Standards for Hazardous Air Pollutants, re-
gulations as defined in Section 112 of the Clean Air Act which re-
gulate asbestos, mercury, beryllium, benzene, arsenic, vinyl chlo-
ride, radionuclides and any other substance for which no ambient
air quality standard is applicable and which in the judgement of
the EPA Administrator may cause an increase in mortality, or an
increase in serious irreversible or incapacitating reversible ill-
ness. (40 CFR Part 61)
13
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New source - Any stationary source the construction or modification of
which commences after the publication of regulations or prooosed
regulations which prescribe a standard of performance which is
intended to apply to that type of air pollution emission source.
New source performance standards - see NSPS.
NOR stain - Non-grain raising stain used on wood furniture. These are
usually organic borne because of the tendency of water to cause
the grain of wood to swell.
Nonattainment area - An area, as defined under Section 107 of the Clean
Air Act, which is in violation of one or more of the national
ambient air quality standards.
NSPS - New source performance standards, i.e. standards for emission
of air pollutants from new, modified or reconstructed sta-
tionary emission sources which reflects the degree of emis-
sion limitation achievable through the application of the best
system of emission reduction which (taking into account the cost
of achieving such reduction) the administrator determines has
been adequately demonstrated. The Clean Air Act usually refers to
these as standards of performance for new stationary sources.
OAQPS - The Office of Air Quality Planning and Standards, a part of the
U.S. Environmental Protection Agency.
Offset lithography - A method of printing in which the image area of
the printing roll is essentially at the same level as the nonimage
area. The ink wets the image area only and the nonimage area is
wetted by water. Ink is transferred from the printing roll to the
rubber surface on a roll called the blanket cylinder which trans-
fers the ink to the paper. When a web or continuous roll of paper
is used, the process is called "web offset."
Olefins - A class of unsaturated aliphatic hydrocarbons having one or
more double bonds. The double bond makes these compounds highly
chemically reactive and useful as starting materials for the manu-
facture of other compounds. Examples are ethylene and propylene.
Orange peel - A paint surface appearance, characterized by small pits,
resembling the surface texture of an orange. Depending on the pro-
duct, this may be desirable (appliances) or highly undesirable
(automobiles).
Organic aerosol - Fine organic particles or droplets which remain dis-
persed in the atmosphere.
Orgam'sol - A thick coating consisting of resin and plasticizers and
some organic solvent which is often used to coat flexible sub-
strates such as paper or fabrics. It is similar to a plastisol
except that an organise! contains more organic solvent.
Oven - Enclosed area in which a coating is heated and baked or cured.
14
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Overall control - The product of the capture efficiency and the control
device efficiency gives an overall control efficiency for the pro-
cess.
Overspray - That solids portion of a coating sprayed from a spray ap-
plicator which fails to adhere to the part being sprayed. (Applied
solids plus overspray solids equal total coating solids delivered
by the spray application system.)
Overvarnish - Coating applied over the ink on the outside of beverage
cans to provide gloss and protect the can from corrosion and abra-
sion.
Oxygenated solvent - An organic solvent containing oxygen as part of
the molecular structure. Alcohols and ketones are oxygenated com-
pounds often used as paint solvents.
Ozone - An oxygen molecule composed of three oxygen atoms. It is a
component of photochemical smog and its concentration in the air
is regulated by pollution control laws. It is a pollutant which
meets the criteria of Section 110 of the Clean Air Act.
Paper coating - As used in Environmental Protection Agency's control
technique guidelines, is the coating of paper, plastic film or me-
tallic foil usually with a roll, knife, or rotogravure coater.
Percent capture - The ratio of solvent vapors collected into the cap-
ture system to the amount of solvent vapors released by a process
expressed as a percentage.
Photochemical oxidant - Ozone and smaller amounts of other irritating
chemicals such as peroxyacetyl nitrate which are products of atmos-
pheric reactions of volatile organic compounds, NOX and sunlight.
Photochemical q/idants are a major portion of the air pollution
commonly known as "smog".
Photochemical reactivity - Measure of the rate at which an organic com-
pound reacts in the presence of ultraviolet radiation to form pho-
tochemical oxidants.
Pigment - A finely ground insoluble powder dispersed in a coating to
gTve a characteristic color.
Pinhole - An imperfection in a paint film which resembles a hole caused
By" penetration with a pin.
Plasticizer - A substance added to a polymer composition to soften and
add flexibility to the product.
Plastisol - A coating made of a mixture of finely divided resin and a
plasticizer. It is applied as a thick gel which solidifies when
heated.
15
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Precursor - In photochemical terminology, a compound such as a volatile
organic compound which "precedes" oxidant. Precursors react in
sunlight to form ozone or other photochemical oxidants.
Pressure sensitive adhesive - An adhesive which, when placed on a back-
ing material,adheres to another surface on contact without
wetting, heating or adding a curing agent.
Primary heat recovery - A method of conserving energy by using heat
from incinerator exhaust gases to preheat the inlet gases to the
inci nerator.
Primer - First layer of coating applied to a surface.
Primer surfacer - A coating, usually applied over a thin primer, which
gives "Ixxly" to the surface, fills in irregularities and unlike
the primer, is intentionally thick enough to permit sanding with-
out cutting through to bare metal. A topcoat is applied over a
primer surfacer.
Pot life - The amount of time a paint may be stored before it hardens
and can no longer be used. This usually refers to catalyzed or
"two component" coatings which may have a pot life of only a few
hours after the two components are combined.
Powder coating - A coating applied as a dry powder which, when baked at
sufficiently high temperature, flows out to form a continuous film.
Print paste - A pigmented coating used to render designs on fabric, us-
ually applied by the roller, rotary screen or flat screen printing
processes. Mineral spirits are the solvent in print pastes.
Promulgation - The publication of a final rule in the Federal Register.
Promulgation is preceeded by a formal proposal published in the
Federal Register and an intervening public comment period.
Proposal - The publication of a rule in a preliminary (not final) form
in the Federal Register. Usually comments are invited from the
affected public"! ano"the final rule is promulgated only after
these comments are considered.
PSD - Prevention of Significant Deterioration refers to regulations
requiring preconstruction review of major new sources and major mo-
difications locating in attainment or unclassified areas (clean
air areas). The requirements are outlined in 40 CFR 52.21, 40 CFR
51.24, and Part D of the Clean Air Act. The objective of the PSD
program is to assure that areas of the country that are relatively
free from air pollution remain that way.
RACT - "Reasonably available control technology" - the lowest emission
limit that a particular source is capable of meeting by the appli-
cation of control technology that is reasonably available consi-
dering technological and economic feasibility. RACT is usually
applied to existing sources in nonattainment areas and in most
cases is less stringent than new source performance standards.
16
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Radiation cure - Method of curing or drying coatings by exposure to
electromagnetic waves or particles such as infrared, ultra-violet,
or electron beam.
Reactive compound - A volatile organic compound which is a precursor,
i.e., reacts in the atmosphere to form photochemical oxidants.
Almost all organic compounds are photoreactive, but a few have
such low reactively that they are usually considered nonreactive.
Solvents that have been deemed of negligible photochemical reac-
tivity by EPA are: methane, ethane, 1,1,1-trichloroethane
(methyl chloroform), methylene chloride, trichlorofluoromethane
(CFC-11), dichlorodifluoromethane (CFC-12), chlorodifluoromethane
(CFC-22), trifluoromethane (FC-23), trichlorotrifluoroethane
(CFC-113), dichlorotetrafluoroethane (CFC-114), and chloropenta-
fluoroethane (CFC-115).
Reconstructed source - An existing facility in which components are
replaced to such an extent that the fixed capital cost of the new
components exceed 50 percent of the fixed capital cost that would
be required to construct a comparable entirely new facility. New
source performance standards may be applied to sources, which are
reconstructed after the proposal of the standard if it is techno-
logically and economically feasible to meet the standard.
Recovered solvent - Solvent which is extracted from a process or ex-
haust stream usually by adsorbtion or condensation.
Reducing solvent - A solvent added to dilute a coating usually for the
purpose of lowering the coating's viscosity.
Reference method - Any method of sampling and analyzing for an air
pollutant which is published in Appendix A of 40 CFR 60.
Regulatory alternative - Any of several air pollution control strate-
gies or options that are considered during the development of a
regulation. Each such alternative is evaluated in terms of cost
of control and economic impact on the industry.
Release coating - A coating applied to a substrate (usually a flexi-
ble one)which limits the adherence of a pressure sensitive
coating. This is used as a covering sheet for pressure sensitive
labels so that the labels can be pulled off and used. The back
side of adhesive tapes are coated with release coating to allow
the tape to be unrolled.
Reverse roll cpater - A roll type coater for paper, film, foil and
metal coil which applies coating to the web by a roll which turns
in a reverse direction to the direction of travel of the web.
This procedure is said to reduce striations in the coating.
Roll coating (Roller coating) - Method of applying coating to a flat
sheet or strip in which the coating is transferred by a roller or
series of rollers.
17
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Rotary screen printer - A widely used fabric printing technique in
which a moving fabric web passes in contact with a series of rota-
ting drums. The cylindrical drums have holes in the drum surface
in the shape of a pattern. Liquid print paste is forced through
the holes in the drum surface onto the fabric, leaving a pattern
on the fabric surface.
Rotational electrostatic spray - A spray paint device which uses a ro-
tating bell or disk to shear the paint into a fine mist and which
efficiently draws the paint onto the part being painted by elec-
trostatic forces.
Rotogravure - A method of printing in which the image areas of the
printing roll are recessed relative to the background. The image
is in the form of cells or cups mechanically or chemically etched
in the surface. Typically, a gravure cell is 35 microns deep by
125 microns square, with 22,500 cells in the square inch.
Rule 66 - An air pollution regulation passed by the Los Angeles Air
Pollution Control District in 1966. This regulation was aimed at
controlling hydrocarbons and defined certain types of compounds as
unreacting and exempt from control. This was one of the first VOC
regulations, was very influential and was widely copied by other
juri si dictions.
Salt spray test - A test to determine corrosion resistance of paints by
exposing a standardized steel panel to a salt (sodium chloride)
solution fog. The length of time until the panel corrodes
gives a measure of corrosion resistance of the paint.
Sealer - A coating used to seal the pores of a surface, especially a
wood surface, before additional coats of paint or varnish are add-
ed.
Secondary heat recovery - Use of heat from an incinerator exhaust for
uses within a plant such as heating an oven or a room. This is
distinguished from primary heat recovery which is the use of
the hot incinerator exhaust gases to heat the inlet gases to the
incinerator.
Section 111 - A section of the Clean Air Act which requires development
of standards of performance for new stationary sources (new source
performance standards).
Section Hid - A part of Section 111 of the Clean Air Act that regu-
lates emissions of noncriteria and nonhazardous air pollutants
(which are the so called "designated pollutants"). After EPA
issues an NSPS for a new source category, state air agencies must
submit to EPA a plan to control emissions of designated pollutants
from existing sources in that category.
Section 112 - A section of the Clean Air Act which requires development
of national emission standards for hazardous air pollutants.
18
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Section 114 - A section of the Clean Air Act giving the Environmental
Protection Agency authority for information gathering inspections,
and monitoring and provides for EPA personnel to have access
into plants with air pollution emissions.
Shade - A color coat used on wood furniture which gives character to
^^the finish. It is often applied by hand wiping with a rag.
SIC code - Standard Industrial Classification, a numerical identifica-
^H^fn system developed by the U. S. Government for statistical pur-
purjosts and widely used by business firms. Industries are
grouped into similiar categories and each category is given a
number representing the category.
Side seam sealer - A compound for protecting the side seam of three
piece cans.
SIP - State Implementation Plans are required by Section 110 of the
— Clean Air Act as amended. Each State is to subnit a plan to the
EPA Adm nistrator which provides for implementation maintenance
and enforcement of the national ambient air quality standards.
Smog - A common name for the visible haze which results from air pollu-
tion containing photochemical oxidants.
Speciality printing - Printing on such items as food packages and
5th er than printing of publications.
Spray booth - An enclosed, ventilated area used for spray painting.
Solvent - A liquid used in a paint or coating to dissolve or disperse
^TTlm-forming constituents and to adjust viscosity I •evaporates
during drying and does not become a part of the dried film.
Solvent density - The weight per unit volume of a solvent or solvent
mixture This number is often used in calculating the VOC emis-
s Ss from coatings. Densities of common organic solvents range
from 6.6 lb/gal to 9.5 Ib/gal. The Environmental Protection A-
gency has chosen 7.36 Ib/gal as an average density of a coating
solvent mixture to use in some calculations.
Solvent borne coating - Coatings which contains only organic solvents.
If water is present, it is only in trace quantities.
Stain - A wood coating which is used to give color to wood. Stains
^^usually have low solids and high solvent content, i.e., often
greater than 95% solvent by volume.
of oerformance - Standards for emission of air pollutants
from new modVtled or reconstructed stationary emission sources
which reflect the degree of emission limitation achievable
through the application of the best system of emission reduction
which (taking into account the cost of achieving such reduction)
19
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the administrator determines has been adequately demonstrated.
These are also commonly known as new source performance standards
(NSPS).
STAPPA - State and Territorial Air Pollution Program Administrators.
Substrate - The surface to which a coating is applied.
Surface coating operation - The application of a film which covers the
surface of some object. Painting and varnishing are common surface
coating operations as are coatings applied to fabric, paper,
plastic film and metallic foil.
Surfacer - A coating applied over a primer to provide a uniform surface
thTck enough to permit some sanding before application of a
topcoat. Surfacer is also known as primer surfacer.
Textile printing - The decorative enhancement of cloth by applying a
pattern or colored design with inks, dyes, or print pastes. The
design is usually applied by roller, flat screen or rotary screen
techniques.
Theoretical VOC content - The quantity of VOC which will be released
during application, flashoff and cure per unit volume of coating
(or coating solids).
Thermal incinerator - A device for oxidizing waste material via
flame and heat. This contrasts with a catalytic incinerator which
incorporates a catalyst to aid the combustion.
Thinner - A liquid used to reduce the viscosity of a coating and which
wTll evaporate before or during the cure of a film.
TLV - Threshold Limit Values (TLV) represent the air concentrations of
chemical substances to which it is believed that workers may be
daily exposed without adverse effect.
Topcoat - The last coat applied in a coating system.
Total enclosure - An enclosure around the coating head of a web coating
lineor other coating application device so that all volatile or-
ganic compounds (VOC) from the coating application and flashoff
operations are collected and ducted through a stack or into the
oven. With a total enclosure on a coating line there will be no
fugitive emissions, only stack emissions. Some air pollution re-
gulations may require a total enclosure so that all VOC emitted by
the process can be measured.
Total organic compound (TOO - Those compounds measured according to the
procedures in an applicable test method.
Touch-up coating - Often, after a metal part such as an automobile body
or large appliance goes through a coating line, small paint imper-
fections will be present which are corrected later in a separate
20
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spray booth. This process is called "touch-up". Volatile organic
compounds from this repair process may be treated differently than
emissions from the main coating line in regulations.
Trade Association - An organization formed by members of an industry to
promotetfie business of the industry as a whole or to encourage
scientific and technical advances which will benefit the industry.
Government air pollution regulators often talk to trade associa-
tions who have an interest in volatile organic compound regula-
tions. Prominent among these are:
American Petroleum Institute
American Society for Testing Materials
Can Manufacturers Institute
Chemical Manufacturers Association
Flexible Packaging Association
Graphic Arts Technical Foundation
International Gas Cleaning Institute
Motor Vehicle Manufacturers Association
National Coil Coaters Association
National Paint and Coatings Association
National Spray Equipment Manufacturers Association
Powder Coating Institute
Rubber Manufacturers Association
Trade journal - A magazine devoted to the interests of a specific in-
dustry.
Trade sales - Paint sold as shelf goods through retail outlets to the
general public and used mainly for coating of architectural struc-
tures.
Traffic paint - Any coating used for traffic control such as to paint
center! ines on highways and also for parking lot and curb markings.
Transfer efficiency - The ratio of the amount of coating solids depo-
sited onto the surface of the coated part to the total amount of
coating solids used.
Three-piece can - A can made of three different pieces, a body, a top,
and a bottom.
Two component paint - A coating which is manufactured in two compo-
nents which must be maintained separate until shortly before use.
When mixed, the two liquids rapidly crosslink to form a solid
composition.
Two-piece can - A can which consists of a body and bottom manufactured
from a single piece of steel or aluminum and a separate top which
is attached to the body.
Units - In air pollution regulatory usage, units are the dimentional
quantities such as length, weight, or volume in which an air pol-
lution regulation or a guideline is expressed. In the series of
21
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reports known as Control Techniques Guidelines, suggested RACT le-
vels are given in units of "Ibs of VOC per gallon of coating (less
water)". The metric euivalent of this can also be used: "Kg of
VOC per liter of coating (less water)". For new source perfor-
mance standard regulations, units of "Kg of VOC per liter of
coating solids" have been used. These latter units permit easier
consideration of transfer efficiency in any calculations that are
required. Figure B-l, in Appendix B, allows rapid calculation of
the solvent content, in pounds of VOC/gallon of coating (less
water) of three important types of coatings when the volume per-
cent solids is known.
Urethane coating - A one or two part coating which contains polyisocya-
nate monomer and a hydroxyl -containing material which react during
cure to form polyurethane. The basis reaction is:
R2OH — >R1NHCOOR2.
Ultraviolet (UV) - Electromagnetic radiation of wavelength between 10
and 400 nanometer. Sources of UV are used to cure coatings which
are specially designed for this purpose.
Vapor capture system - Any combination of hoods and ventilation system
that captures or contains organic vapors in order that they may be
directed to an abatement or recovery device.
Varsol - The brand name of Exxon produced mineral spirits.. Varsol is
often used as the solvent in print paste for fabric painting.
Vinyl plastisol - An emulsion of polyvinyl chloride (PVC) resin,
plasticizers, emulsifiers and stabilizers. It might contain a
small amount of diluent, 1-5 percent, for viscosity control.
Vinyl printing ink - Any mixture or solution containing a polymeric
resin and dye or pigment which is applied in decorative patterns
to vinyl sheets or coated webs using a rotogravure printing
process.
Vinyl printing and top-coating - The application of a decorative pat-
tern to a vinyl sheet or coated web with a rotogravure type print-
ing press. Frequently a thin, protective top coat is applied by
the last print head of the press.
Viscosity - A measure of a coating's resistance to flow.
VOC - See volatile organic compound.
Volatile Organic Compound (VOC) - Any organic compound which partici-
pates in atmospheric photochemical reactions; that is, any organic
compound other than those which the Administrator designates as
having negligible photochemical reactivity. VOC may be measured
by a reference method, an equivalent method, an alternative method
or by procedures specified under any subpart. A reference method,
22
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an equivalent method, or an alternative method, however, may also
measure nonreactive organic compounds. In such cases, an owner or
operator may exclude*the nonreactive organic compounds when deter-
mining compliance with a standard. The Administrator has desig-
nated the following organic compounds as negligibly reactive:
methane, ethane, 1,1,1-trichloroethane (methyl chloroform), methy-
lene chloride, trichlorofluoromethane (CFC-11), dichlorodifluoro-
methane (CFC-12), chlorodifluoromethane (CFC22), trifluorornethane
(FC-23), trichlorotrifluoroethane (CFC-113), dichlorotetrafluoro-
ethane (CFC-114), and chloropentafluoroethane (CFC-115).
Volume percent solids - The portion of a coating which remains as part
of the cured film expressed as percent by volume. This contrasts
to another convention of expressing solids content by weight per-
cent. Often a percentage is given without specifying whether vol-
ume or weight. This is confusing and leads to errors in coating
calculations. Fiaure B-l in Appendix B allows quick estimation of
the solvent content, in pounds of VOC per gallon of coating (less
water), when the volume percent solids is known.
Washcoat - A wood furniture coating which is applied after the body
stain. It seals the wood surface and stiffens the wood fibers for
subsequent sanding.
Waterborne coating - A coating which contains more than five weight
percent water in its volatile fraction.
Waterwash spray booth - A spray booth in which water is used to col-
lect overspray. Ventillation air is drawn through the water and
paint overspray is captured in the water from which it can be
recovered as sludge. The waterwash may help the booth to be
kept free of overspray buildup and may reduce the necessity of
frequent cleanings.
Weather resistance - The ability to undergo exposures to weather
without failure, which is an important paint characteristic. Many
new paints are tested by exposure to weather for several years
before the paint is judged acceptable for specific use.
Web coating - Coating of fabric, paper, plastic film, metalic foil,
metal coil or other products which are flexible enough to be
unrolled from a large roll, coated by blade, roll coating or
rotogravure as a continuous sheet and, after cure, rerolled.
Weight percent solids - The portion of a coating which remains as part
of the cured film expressed as percent by weight. This contrasts
to another convention of expressing content by volume percent.
23
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APPENDIX A
SURFACE COATING EMISSION CALCULATIONS
How to Determine
The volume of coating needed to do a particular job
The difference (expressed as a percentage) in emissions
between two coatings
The emission reduction (expressed as a percentage) needed to
meet an emission limit
The effect of improvements in transfer efficiency
25
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0 HOW MUCH COATING IS NEEDED TO DO A PARTICULAR JOB?
The same volume of coating solids must be deposited on an object
to coat it to a desired film thickness regardless bT the type of
coating or volatile organic compound content of the coating used.
Solids make the film. Volatiles (VOC, water, and non-photochemically
reactive solvents) evaporate.
Four gallons of a 25 volume percent (v/o) solids coating must be
used to get one gallon of coating solids.
VOC
SOLIDS
VOC
SOLIDS
VOC
SOLIDS
VOC
SOLIDS
But, only two gallons of a 50 v/o solids coating must be used to get
one gallon of coating solids.
VOC
VOC
SOLIDS
SOLIDS
26
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This means that twice as much work can be done with a gallon of
50 v/o solids coating than with a gallon of 25 v/o solids coating.
Twice as many gallons of 25 percent solids coating are needed than
gallons of 50 percent solIds coating to do the same job.
HOW DO EMISSIONS FROM DIFFERENT COATINGS COMPARE?
Comparisons of the percent difference 1n emissions between two
coatings, or between a coating and an emission limit, must be done on
a solids basis.
VOC.
Each gallon of the 25 v/o solids coating contains 5.5 pounds of
5.5 IBS.
VOC
SOLIDS
So, for each gallon of coating solids, 22.0 pounds of VOC are
emitted.
5.5 pounds VOC
gallon coating
4 gallons coating
gallon solids
Each gallon of the 50 v/o solids coating contains 3.7 pounds
of VOC.
27
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So, for each gallon of coating solids, 7.4 pounds of VOC are
emitted.
3.7 pounds VOC
gal ion coating
2 gallons coating
gallon solids
Thus, emissions from the 50 v/o solids coatings are 66 percent
less than from the 25 v/o solids coating when providing an equal
amount of solids to the process.
22.0-7.4
0.66
0 WHAT EMISSION REDUCTION IS NEEDED TO MEET AN EMISSION LIMIT?
This calculation, which must also be done on a solids basis,
is the same as that used above tocompare emissionsi from two
different coatings.
A coater who uses a 25 v/o solids coating containing 5.5 pounds
of VOC per gallon, less water, must reduce emissions by 66 percent
to meet an emission limit of 3.7 pounds of VOC per gallon,
less water.
HOW MUCH DO IMPROVEMENTS IN TRANSFER EFFICIENCY HELP A SOURCE TO
COMPLY?
The coater may want to use a coating that does not comply with a
regulation and compensate by improvements in the transfer efficiency
with which the coating is applied to meet an equivalent emission
level. In order to calculate credit for VOC reductions which result
from improvements in transfer efficiency, calculations should be done
using units of:
Ib VOC
gallon son as deposited
These units are determined by dividing Ib VOC/gallon solids by
the transfer efficiency expressed as a decimal fraction. For
example, if the starting transfer efficiency is 60 percent, the units
would be:
1.0 gal solids
Ib VOC = Ib VOC x in coating used
U.bU gal solids
gal solids deposited
(with the old system)
gal solids
in coating used
deposited
28
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If the same paint were now to be sprayed with 90 percent
transfer efficiency, the new value would he:
1.0 gal solids
1b VOC = 1b VOC x in coating used
gallon solids gallon solids 0.90 gal solids
deposited in coating used deposited
(with new system)
If both the solvent content of the coating and the transfer
efficiency are changed, the situation becomes:
1.0 gal solids in
lb VOC = Ib VOC v new coating used
gal solids deposited gal solids in j gal solids
(with new paint and new coating deposited
new transfer efficiency) used
where j = the new transfer efficiency expressed as a decimal
Expressed in these units, the emissions from the old and new
systems can be directly compared to determine the reduction achieved.
NOTE: For metal furniture and appliance coating, the EPA has
recommended* that credit for transfer efficiency be given from a base-
line of 60 percent transfer efficiency (TE). For example, if a
company goes from 35 percent TE to 85 percent TE, credit should only
be given for going from 60 percent TE to 85 percent TE to avoid
rewarding a source that has historically had poor transfer efficiency
- hence a high emission rate.
The rationale for this is that 60 percent TE is a reasonable
transfer efficiency to achieve for these industries, and credit
should only be given for exceeding 60 percent TE.
For the automobile industry, the CTG recommendation for baseline
transfer efficiency is 30 percent TE for both primer surfacer and
topcoat. This is the efficiency at which waterborne coatings were
applied at two existing assembly plants.
* Memo from G. T. Helms, Chief, Control Programs Operations Branch,
EPA, to Chief, Air Programs Branch, EPA Regions I-X, "Appropriate
Transfer Efficiencies for Metal Furniture and Large Appliance
Coating", November 28, 1980.
29
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APPENDIX B
RAPID CONVERSION AIDS*
* The graphs Tn this appendix are based on graphs on Page 1-4 and
on Page D-4 in "Control of Volatile Organic Emissions from Existing
Stationary Sources - Volume II: Surface Coating of Cans, Coils,
Paper, Fabrics, Automobile, and Light-duty Trucks, EPA-450/2-77-008,
May, 1977
31
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52
CURVES FOR WATER-BORNE
COATINGS ARE FOR WATER/SOLVENT
RATIOS OF 70/30 AND 80/20.
1 -
30 40 50 60 70
SOLIDS IN COATING, Vol %
Figure B-1. Approximate weight of organic solvent per gallon
of coating (less water) for three coatings as a function of'solids
content. (A 40 volume percent solids coating could contain as
little as 1.7 pounds of VOC per gallon of coating (less water) if
it is of the 80/20 water-borne type, or as much as 4.4 pounds
for an organic-borne coating).
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I I I
SOLVENT CONTENT
OF ORIGINAL
COATING.
IbVOC/gal COATING
(LESS WATER)
12345
SOLVENT CONTENT OF REPLACEMENT
COATING, IbVOC/gillon COATING (LESS WATER)
Figure B-2. Approximate reduction in emissions which occurs
by replacing a higher solvent coating with one of lower solvent
content. (In the example above, a 74 percent reduction in
emissions can be obtained by replacing a coating with a solvent
content of 5.1 pounds of VOC per gallon, less water, with a
coating which contains 2.8 pounds of VOC per gallon, less
water).
33
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APPENDIX C
EXAMPLES OF DETERMINING COMPLIANCE ALTERNATIVES
USING GRAPHICAL AIDS
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EXAMPLES OF COMPLIANCE SITUATIONS
CASE 1
SITUATION:
A company using an organic-borne coating with a VOC content of 5.1
Ihs. of VOC per gallon of coating (less water) must comply with a State
regulation that limits it to 2.8 Ibs. of VOC per gallon of coating
(less water). What are the company's options for compliance?
RAPID DETERMINATION OF ALTERNATIVES
STEP 1 - Figure C-l (which is equivalent to Figure B-l in Appendix B)
indicates three coatings that meet the 2.8 Ib VOC/gallon of coating
(less water) regulation: An 80/20 waterborne coating with 24 volume
percent solids, a 70/30 waterborne coating with 33 volume percent
solids, and an organic-borne coating with 62 volume percent solids.
Conversion of the process to use any of these would comply with the
regulation.
CURVES FOR WATER BORNE
COATINGS ABE FOB WATER/SOLVENT
RATIOS OF 70/30 AND 80/20
SOlVfNT DENSITY = 7 36 lb,V
SOLIDS IN COATING. Vol %
Figure C-1 Approximate weight of organic solvent per gallon
of coating (less water) for three coatings as a function of sohds
content
STEP 2 - If compliance with an add-on control device such as-an incin-
erator or carbon adsorber is desired (instead of changinq the coating)
use Figure B-2 in Appendix B to determine that a change from a coating
with 5.1 Ib VOC per gallon of coating (less water) to one with 2.8 Ib
VOC per gallon (less water) represents about a 74 percent reduction in
emissions. Any combination of capture device and control system that
will achieve an overall 74 percent reduction would be an equivalent
compliance scheme.
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CAUTION - Avoid the erroneous tendency to calculate the required reduc-
tion in Step 2 by this method:
5.1 - 2.t
5TI
100% = 45%
Such a calculation does not truly compare the relative amounts of
VOC needed to apply the same volune of coating solids.
CASE 2
SITUATION:
A company using an organic-borne coating with a solvent content of
30 volume percent solids must comply with a State regulation that
limits it to 2.8 Ibs of VOC per gallon of coating (less water). What
are the company's option's for compliance?
RAPID DETERMINATION OF ALTERNATIVES
STEP 1 - Use Figure C-2 (which is equivalent to Figure B-l in
Appendix B) to find that an organic-borne coating with 30 volume
percent solids contains 5.1 Ibs. of VOC per gallon of coating less
water. (Obviously, the company is not currently in compliance with
the regulation.)
From thi9 point, the example is identical with the situation in
CASE 1. Go to Step 1 in CASE 1 and proceed through that example.
CURVES FOR WATER BORNE
RATIOS OF 70/30 AND M/20
SOLVENT DENSITY = 7 36 Ib/ul
10 20 30 40 SO 60 70 «
SOLIDS IN COATING Vol%
Figure C-2 Approximate weight of organic solvent per gallon
of coating (less water) for three coatings as a function of solids
content
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CASE 3
SITUATION:
A coating plant with several coating lines is currently using
100 gallons/day of a 5.1 Ib VOC/gallon (less water) conventional
solvent-borne coating to coat a given output of products, but the
company must now comply with a State regulation that limits it to
2.8 Ibs of VOC per gallon of coating (less water).
The company want to calculate the daily maximum VOC emissions
from the plant that will be permitted by the new regulation at their
current production rate. The plant is located in a State that will
permit the emissions from all lines to be considered as a "bubble."
The company wants to vary the amounts of solvent used on each coating
line, but in such a way that the total daily maximum allowable
emissions for the whole plant are never exceeded.
Calculate the daily allowable emissions under this "bubble."
STEP 1- Remember that essentially all equivalency calculations must
be based on the volume of coating sol ids not volumes of coating.
STEP 2- Figure C-2 shows that the existing 5.1 Ib VOC/gal coating
contains approximately 30 volume percent solids. Therefore, the
amount of coating solids sprayed each day is equal to:
100 gal coating/day x 0.30 gal solids = 30 gal solids/day
gal coating
STEP 3 - Figure C-l shows that a solvent-borne coating complying with
the 2.8 Ib VOC/gal of coating (less water) limitation contains 62
volume percent solids.
STEP 4 - The amount of solids required at a constant production rate
will be the same (30 gallons solids/day) regardless of whether the
original or the complying coating is used.
For the complying coating, the usage rate in gallons of coating
required is:
gal coating = 30 gal of solids applied x 1 gal complying coating
reauired 3ay 0.62 gal solids
gal coating = 48.4 gal complying coating needed/day
required
STEP 5 - Calculate the allowable emissions.
Allowable = 2.8 Ib VOC x 48-4 gal complying coating
emissions gal complying day
coati ng
= 135 Ib VOC/day
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CAUTION - Avoid the error of calculating allowable emissions in the
following way:
100 gal/day x 2.8 1b VOC = 280 Ib VOC/day
~
This is incorrect and allows a high emission rate which is not
in compliance with the regulation.
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TECHNICAL REPORT DATA
(Pteau nod Italruenons on rt« wen* 6e/Ofe comptetuttt
REPORT NO.
EPA 450/3-83-01 3R
RECIPIENT'S ACCESSION NO.
Glossary For Air Pollution Control of
ndustrial Coating Operations (M1th Graphical Aids for
apid Estimation of Acceptable Compliance Alternatives)
REPORT DATE
December 1983
AUTHORIS) Second Edition
B PERFORMING ORGANI
0 PROGRAM ELEMEN
ffice of Air Quality Planning and Standards
.S. Environmental Protection Agency
esearch Triangle Park, NC 27711
1 CONTRACT/GRANTNO-
2. SPONSORING AGENCY NAME AND ADDRESS
13. TYPE OF REPORT AND PERIOD COVE'-tO
14 SPONSORING AGENCY CODE
EPA/200/04
ABSTRACT
Common terms used in the air pollution control of emissions from industrial
coating operations are defined. The definitions cover both coatings
terminology and terms related to the Clean Air Act. Appendices give
sample calculations to illustrate emission reductions achieved by changing
coatings. Graphical aids which simplify calculations are shown.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b IDENTIFIERS/OPEN ENDED TERMS
:. COSATI Field/Group
Air Pollution
Coatings
Pollution Control
Volatile Organic Compounds
Air Pollution Control
13 B
18. DISTRIBUTION STATEMENT
iECURITY CLASS (ThisRtpo
Unclassified
20 SECURITY CLASS (This page)
Unclassified
39_
22 PRICE
EPA F«« 2J20-I
PK«VIOU1 EOITION l» OMOL.TI
41
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U.S. Environmental PT: •<•-"-
Region 5, Library (™ -'
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