State of California
AIR RESOURCES BOARD
Crystal Ballroom
Hotel San Franciscan
1231 Market Street
San Francisco, CA
September 27, 1978
10:00 a.m.
AGENDA
Page
78-17-1 Approval of Minutes of August 7, 1978 001
78-17-2 Consideration of a Proposed Model Rule for the Control 007
of Volatile Organic compound Emissions from the Surface
Coating of Manufactured Metal Parts and Products
78-17-3 Status Report on sulfur Dioxide Regulations for the 125
South Coast Air Quality Management District
78-17-4 Other Business -
a. Executive Session - Personnel and Litigation
b. Research Proposals
ITEM NO.: 78-17-2
Consideration of a Proposed Model Rule for the Control of
Volatile Organic compound Emissions from the Surface Coating of
Manufactured Metal Parts and Products
RECOMMENDATION
Approve model rule and direct staff to transmit it to the air
pollution control districts in the South Coast, San Francisco Bay
Area, San Diego, San Joaquin Valley, North Central Coast, South
Central Coast, Sacramento Valley, and Southeast Desert Basin for
consideration as an amendment to their rules and regulations.
SUMMARY
The use of solvents for a variety of cleaning and surface coating
operations are the most significant source of organic gas
emissions from non-vehicular sources in all of California's
metropolitan areas. Volatile organic compound (VOC) emissions
contribute to both oxidant and aerosol formation in the ambient
air. Approximately 8 percent of all solvent-related emissions in
California's urban areas are associated with the painting of
manufactured metal parts and products.
The provisions of the model rule apply to all manufactured metal
parts and products with the exception of automobiles, light-duty
trucks, aircraft, aerospace vehicles, marine vessels, can, coils,
and magnetic wire. Industrial maintenance coatings, which are
applied to surfaces and structures already in service, are also
excluded from the provisions of the model rule. The staff
recommends, however, that the model rule for manufactured metal
parts and products include metal furniture and fixtures, although
a separate model rule was previously presented to the Board,
because the model rule includes the same VOC emission limits
recommended by the staff at the July 26 Board meeting.
The staff has obtained emission data for 639 sources in this
category. The total emissions from these sources amount to
approximately 65 tons per day (43.4 in the South Coast Basin and
18.4 in the Bay Area).
There are additional emissions from an undetermined number of
smaller sources for which data were not readily available.
Coatings used in this source category generally contain about 75
percent organic solvent, almost all of which evaporates as the
coating dries. The staff proposes that emissions from these
coating operations be reduced in two ways, both of which are
commercially available and currently used in a number of coating
operations.
The first method is to require the use of low-solvent coatings
which emit no more than 340 grams of VOC per liter for air-dried
or forced-dried coatings and 275 grams per liter for baked
coatings, excluding water, or an equivalent emission control
measure. Separate limits based upon drying conditions were
necessary due to differences in curing mechanism and its
relationship to the amount of solvent required for acceptable
application and coating performance.
A more stringent limit of 180 grams per liter, excluding water,
is recommended for new sources where the economic impact of
retrofitting existing coating application lines does not exist.
The second method of control requires a minimum application
efficiency of 65 percent. As a result of higher application
efficiency, there is less over spray, and therefore, less
emissions.
The staff projects an estimated emission reduction of 78 percent
or approximately 51 tons per day from the use of low-solvent
coatings alone. An additional but undetermined emission
reduction will occur due to increased application efficiency.
Another reduction of 10 tons per day comes from metal furniture
and fixture coatings.
Two exemptions are provided to minimize economic impacts to small
companies which do not produce large amounts of emissions. The
first exempts coatings which emit less than 20 pounds of VOC per
day, which is equivalent to approximately four gallons per day of
solvent-borne coating, or up to 17 gallons per day of waterborne
coatings. This exemption provides for the use of small amounts
of specialty-type coatings on production lines which utilize
predominately complying coatings or lacquers for tough-up and
repair provided that the total use of non-compliance coatings
does not exceed 20 pounds of VOC per day.
The second exemption allows touch-up and repair work to be done
without electrostatic equipment. This allows improved coating
penetration into recessed areas where Faraday caging (a repelling
of paint particles) might otherwise be a problem.
Of the various low-solvent coatings available, no one system is
best in every situation. Each has a unique set advantages and
disadvantages. The recommended emission limit allows for this
flexibility. In general, higher-solids coatings have the best
cost-effectiveness ration at roughly $0.06 per pound of VOC
reduced. The cost-effectiveness for waterborne coatings is
estimated at $0.40 per pound of VOC reduced. For powder
coatings, the range is $1.34 for a powder system with recovery to
$2.24 without recovery.
Table of Contents
List of Figures. . . . . . . . . . . . . . . . . . . . . . . . . . . . . iv
List of Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iv
I. Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
II. Conclusions and Recommendations . . . . . . . . . . . . . . . . . . .3
A. Conclusions. . . . . . . . . . . . . . . . . . . . . . . . . . .3
B. Recommendations. . . . . . . . . . . . . . . . . . . . . . . . .6
C. Discussion of Model Rule . . . . . . . . . . . . . . . . . . . 10
III. Background. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
A. Industry Overview. . . . . . . . . . . . . . . . . . . . . . . 12
B. Rule Development . . . . . . . . . . . . . . . . . . . . . . . 14
IV. Coating Processes and Emissions . . . . . . . . . . . . . . . . . . 16
A. Description of Coating Processes . . . . . . . . . . . . . . . 16
B. Coatings Presently Used. . . . . . . . . . . . . . . . . . . . 20
C. Emissions Estimate . . . . . . . . . . . . . . . . . . . . . . 23
V. Emission Control Techniques . . . . . . . . . . . . . . . . . . . . 27
A. Low-solvent and Powder Coatings. . . . . . . . . . . . . . . . 27
1. Waterborne Coatings . . . . . . . . . . . . . . . . . . . 28
a. Spray, Dip, and Flow . . . . . . . . . . . . . . . . 28
b. Electrodeposition. . . . . . . . . . . . . . . . . . 44
2. Higher-solids . . . . . . . . . . . . . . . . . . . . . . 46
3. Powder. . . . . . . . . . . . . . . . . . . . . . . . . . 55
B. Increased Application Efficiency . . . . . . . . . . . . . . . 65
C. Add-on Controls. . . . . . . . . . . . . . . . . . . . . . . . 68
1. Incineration. . . . . . . . . . . . . . . . . . . . . . . 69
2. Carbon Adsorption . . . . . . . . . . . . . . . . . . . . 69
D. Potential Emission Reduction . . . . . . . . . . . . . . . . . 70
VI. Impacts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
A. Economic Impact. . . . . . . . . . . . . . . . . . . . . . . . 75
1. Impact to Coating Applicators . . . . . . . . . . . . . . 75
2. Impact to Coating Suppliers . . . . . . . . . . . . . . . 78
B. Energy Impact. . . . . . . . . . . . . . . . . . . . . . . . . 79
C. Environmental Impacts. . . . . . . . . . . . . . . . . . . . . 83
1. Industrial Hygiene. . . . . . . . . . . . . . . . . . . . 83
2. Volatile Amines . . . . . . . . . . . . . . . . . . . . . 84
Reference. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
Appendix A - Coating Performance Properties. . . . . . . . . . . . . .A-1
Appendix B - ARB Survey of Coatings Applied to Metal . . . . . . . . .B-1
Letter Concerning the Consultation Meeting for Large
Appliances. . . . . . . . . . . . . . . . . . . . . . . B-10
Invitation to the Coating Industry to Meet Individually
to Discuss. . . . . . . . . . . . . . . . . . . . . . . B-14
General Metal Coating Operations
Request for Information from Trade Associations . . . . B-16
ITEM NO.: 78-17-3
Status Report on Sulfur Dioxide Regulations for the South Coast
Air Quality Management District.
RECOMMENDATION
None; this is a status report only.
SUMMARY
The California Health and Safety Code requires air pollution
control districts, including the South Coast Air Quality
Management District, to adopt rules and regulations which assure
that reasonable provision is made to achieve and maintain all
applicable ambient air quality standards. Such standards are in
effect for sulfur dioxide (SO2) sulfate, suspended particulate
matter, and visibility reducing particles.
In response to this requirement, the District Board has approved
a strategy for the control of emissions of sulfur oxides SOx).
This strategy is known as Control Strategy II. This strategy is
designed to achieve the state and national standards for SO2,
however, it will not achieve the state ambient air quality
standard for sulfate.