UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
DATE: 29 JUN 1983
SUBJECT: Exclusion of Exempt Solvents From VOC Calculations
FROM: G. T. Helms, Chief
Control Programs Operations Branch (MD-15)
TO: Chief, Air Branch, Regions I-X
It has been brought to my attention that there has been some misunderstanding by various
parties concerning the proper method of excluding exempt solvents from VOC calculations.
This memorandum is to clarify that exempt solvents should be subtracted out from
coatings just like water, with the ultimate value of interest being the mass of VOC per unit volume
of coating less exempt solvent and water.
Attached is a memorandum dated February 26, 1981, from David Salman, Chemical
Applications Section, Chemical Petroleum Branch, to James Berry, Chief, Chemical Applications
Section, Chemical Petroleum Branch, Emission Standards and Engineering Division. This
document includes a discussion and examples of calculations related to the VOC content of
coatings with exempt solvents.
Should you have any questions, please contact the Technical Guidance Section (Brock
Nicholson or Bill Polglase, FTS 629-5516).
Attachment
DOW CHEMICAL U.S.A.
BARSTOW BUILDING
2020 DOW CENTER
MIDLAND, MICHIGAN 48640
May 13, 1983
Mr. Tom Helms
Chief of Control Programs, Operations Branch
Mail Drop 15
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
CALCULATION OF VOC CONTENT OF GRAPHIC ARTS INKS CONTAINING COSOLVENT BLENDS
WITH NON-VOC SOLVENTS
Dear Mr. Helms:
We are writing you in accordance with a recommendation by David Salman in the Chemicals &
Petroleum Branch of the U.S. EPA. It is our hope that you can clarify differing interpretations on
the calculation of VOC from graphic arts inks containing the non-VOC solvents 1,1,1
trichloroethane and methylene chloride.
As you are aware, the Federal EPA has exempted these two solvents from the definition of VOC.
Federal Register references on that exemption are:
42 FR 35314 of July 8, 1977
42 FR 3274 of January 16, 1979
44 FR 32042 of June 4, 1979
45 FR 32424 of May 16, 1980
45 FR 48941 of July 22, 1980
To date, 92% of the States with SIP's on VOC's have exempted, 1,1,1-trichloroethane from the
definition of VOC and from subsequent control of VOC in surface coatings and graphic arts.
About 88% of these States have similarly exempted methylene chloride.
In the State of Tennessee, a graphic arts company, which has been working closely with its local
EPA representative, is ready to use this option to meet VOC emission limitations. However, a
question has arisen on how to treat the non-VOC solvent in determination of VOC content from
their gravure inks. Specifically, one materials supplier believes that the way the regulations are
written preclude 1,1,1-trichloroethane and methylene chloride being blended with VOC
cosolvents. In their opinion, it is an "all or nothing" situation. The various States SIP's read:
"The volatile fraction of the ink, as applied to the substrate, contains 25.0 percent by
volume or less of organic solvent and 75.0 percent by volume or more of water;"
Since 1,1,1-trichloroethane and methylene chloride are neither (volatile) organic compounds nor
water, the supplier interprets the above to mean that any ink using a blend of 1,1,1-
trichloroethane and/or methylene chloride with other organic solvents will always calculate to
100% organic solvent.
Mr. Tom Helms May 13, 1983 Page Two
This has not been the interpretation by other parties for graphic arts or other surface coatings.
Interpretation by most State and Federal regulators has been that these solvents should be treated
as water is treated in the calculation of VOC. (See the enclosed February 26, 1981, memo on
"VOC Content of Coatings with Exempt Solvents" by David Salman.)
We would deeply appreciate whatever guidance you can provide us or the various regional offices
of the EPA on the calculation of VOC content of graphic arts inks containing cosolvent blends
with the non-VOC solvents. Please feel free to call us for specifics of particular customer usage.
Sincerely,
cc: Carol K. Niemi Raul M. Oteiza
Inorganic Chemicals Department Inorganic Chemicals Department
Chlorinated Solvents Section Chlorinated Solvents Section
Phone: (517) 636-1636 Phone: (517) 636-0401
pac
Enclosures
cc: Mr. John Patton Mr. Eric Flowers
Tennessee Air Pollution Control Tennessee Air Pollution Control
150 Ninth Avenue North 150 Ninth Avenue North
Nashville, TN 37203 Nashville, TN 37203
Mr. David Salman
Chemicals & Petroleum Branch
Mail Drop 13
U.S. Environmental Protection
Agency
Research Triangle Park, NC 27711
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
Office of Air Quality Planning and Standards
Research Triangle Park, North Carolina 27711
DATE: FEB 26 1981
SUBJECT: VOC Content of Coatings with Exempt Solvents
FROM: Dave Salman
Chemical Applications Section, CPB (MD-13)
TO: James Berry, Chief
Chemical Applications Section CPB (MD-13)
Many States have exempted certain volatile organic compounds of negligible
photochemical reactivity, such as 1,1,1-trichloroethane and methylene chloride from their VOC
rules. Recently I was asked by a representative of a major supplier of such solvents how to
calculate the reactive (Footnote 1) VOC content of a coating that contained both VOC and
exempt solvents (Footnote 2). I suggested that exempt solvents should be subtracted out from
coatings just like water with the ultimate value of interest being the mass of VOC per unit volume
of coating less exempt solvent and water (Footnote 3). I provided several sample calculations.
These examples are attached.
(Footnote 1) The word reactive has been dropped after this point. All subsequent
references to VOC in this memo and attachments mean reactive VOC.
(Footnote 2) The term exempt solvent as used in this memo and attachments means those
compounds of negligible photochemical reactivity that States are not required to control in their
ozone SIPs. These compounds are listed in Attachment III.
(Footnote 3) Since coatings that contain exempt solvents such as 1,1,1-trichloroethane and
methylene chloride are not likely to also contain water as a solvent, the less water term has been
dropped from the attached examples.
ATTACHMENT I
Given the mass of VOC and mass of exempt solvent per unit volume of coating, determine
the mass of VOC per unit volume of coating less exempt solvent.
Let x = mass of exempt solvent per unit volume of coating
y = mass of VOC per unit volume of coating
d = density of exempt solvent
z = mass of VOC per unit volume of coating less exempt solvent
y
Then z = --------
1 - x/d
Example 1 - Each gallon of coating contains 3 pounds of VOC and 2 pounds of exempt
solvent. The density of the exempt solvent is 11 pounds per gallon.
3
z = ------ = 3.7 pounds of VOC per gallon of coating less exempt solvent
1 - 2/11
Example 2 - Each liter of coating contains 0.2 kg of VOC and 0.4kg of exempt solvent.
The density of the exempt solvent is 1.3 kg per liter.
0.2
1 - ------------ = 0.3 kg of VOC per liter of coating less exempt solvent
1 - 0.4/1.3
Note: The term VOC as used above means reactive VOC only.
ATTACHMENT II
A paint formulator wants to add both VOC and exempt solvent to 0.25 gallons of coating
solids to make 1 gallon of coating. The coating must meet an emission limit of 3 pounds of VOC
per gallon less exempt solvent. What is the maximum amount of VOC that can be added? How
much exempt solvent should be added to make 1 gallon of coating?
The answer to this problem depends on the density of the VOC and exempt solvent. If we
assume that the VOC density is 7.2 pounds per gallon, the exempt solvent density is 11 pounds
per gallon, and let:
x = maximum pounds of VOC that can be added
x
Then: --------------- = 3
.25 + x / 7.2
x = .75 + x / 2.4
.58x = .75
x = 1.3 pounds VOC
Since the VOC has density 7.2 pounds per gallon, this is equivalent to
1.3 / 7.2 = .18 gallons VOC
Finally, to make a full gallon of coating the formulator must still add:
1 - .25 - .18 = 1 - .43 = .57 gallon exempt solvent
or
.57 x 11 = 6.3 pounds exempt solvent
If VOC or exempt solvent with different densities were used the results would differ. The
same calculation can be done using the appropriate solvent densities.
Note: The term VOC as used above means reactive VOC only.
ATTACHMENT III
Compounds of negligible photochemical reactivity that States are not required to control in their
ozone SIPs of February 1981:
methane
ethane
1,1,1-trichloroethane (methyl chloroform)
trichlorotrifluoroethane
methylene chloride
trichlorofluoromethane
dichlorodifluoromethane
chlorodifluoromethane
trifluoromethane
dichlorotetrafluoroethane
chloropentafluoroethane
Federal Register References:
42FR35314 - July 8, 1977
44FR32042 - June 4, 1979
45FR32424 - May 16, 1980
45FR48941 - July 22, 1980
