United States
Environmental Protection
Agency
Office of Air Quality
Planning and Standards
Research Triangle Park NC 27711
Air
E PA Alternative Control
Techniques Document:
Offset Lithographic Printing
EPA 453/R-94-054
June 1994
Supplemental Information Based on
Public Comment on
Draft Control Techniques Guideline
Announced in Federal Register on
Novembers, 1993
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EPA 453/R-94-054
Alternative Control Techniques Document:
Offset Lithographic Printing
Supplemental Information Based on
Public Comment on
Draft Control Techniques Guideline
Announced in Federal Register
Novembers, 1993
Emission Standards Division
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Air and Radiation
Office of Air Quality Planning and Standards
Research Triangle Park, North Carolina 27711
June 1994
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TABLE OF CONTENTS
Section Page
1.0 INTRODUCTION 1
2.0 APPLICABILITY 2
3.0 FOUNTAIN SOLUTION 4
4.0 CLEANING SOLVENTS 6
5.0 CARRYOVER TO HEATSET DRYERS 8
6.0 COMPLIANCE DEMONSTRATION 10
6.1 FOUNTAIN SOLUTION 10
6.2 METHODS 25 AND 25A 11
6.3 METHODS 24 AND 24A 12
6.4 EMISSION LIMITATION AND MATERIAL TESTING 12
APPENDIX A DEFINITION OF VOC COMPOSITE
PARTIAL VAPOR PRESSURE
APPENDIX B OCTOBER 25, 1993 GUIDANCE
ON METHODS 25 AND 25A
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1.0 INTRODUCTION
The purpose of this document is to provide information on
alternative control techniques (ACT) for volatile organic
compound (VOC) emissions from offset lithographic printing.
A draft control techniques guideline (CTG) for this industry was
made available for public comment on November 8, 1993. Over 20
comment letters were received. In developing this ACT document,
we solicited additional information to help us clarify and
understand the basis for the comments on the draft CTG. We have
considered all of the additional information we received, along
with the comments, in preparing this document.
This document supplements the draft CTG. The draft CTG
should not be used alone, but rather in conjunction with this
document. This document provides additional information that
States can use in developing rules based on reasonably available
control technology (RACT).
The discussion of comments on the draft CTG is presented in
the following sections:
Applicability
Fountain Solution
Cleaning Solvents
Carryover to Heatset Dryers
Compliance Demonstration
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2.0 APPLICABILITY
The draft CTG did not suggest a lower size cutoff for
applicability of the recommended levels of control. The
recommended control levels were believed to represent reasonably
available control technology (RACT) for offset lithographic
printers of all sizes.
Several commenters asked that the EPA advise States that in
order to be consistent with the requirements of the Clean Air Act
that the recommendations in the draft CTG should only be applied
to major sources in ozone non-attainment areas. The EPA
disagrees with this interpretation of the potential applicability
of the recommendations in a CTG.
Many of the CTGs developed under the 1977 Clean Air Act
Amendments include a recommendation to apply the guidance to
sources that are much smaller than major sources. For most
coating industry CTGs, there was no cutoff specified in the CTGs
themselves, but a general lower size cutoff of 15 pounds per day
actual VOC emissions without control devices from all activities
in the particular CTG category was suggested by EPA in other
related guidance and adopted into many State regulations. Under
the 1990 Clean Air Act Amendments, one of the categories for
which a CTG was to be developed was automobile refinishing. This
is a category that has few, if any, major sources, and thousands
of smaller sources. There would have been no reason to develop a
CTG for automobile refinishing if it could not be applied to
sources that were not major sources.
If the offset lithography CTG were made final an
applicability cutoff of 15 pounds per day actual VOC emissions
without control devices from all offset lithographic printing
activities (inks, coatings, blanket and roller washes and
fountain solution) would likely have been included to be
consistent with other CTGs. When an applicability cutoff is
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recommended in a CTG, a state may choose to have its regulations
apply to sources whose emissions are less than the cutoff level
recommended in the CTG, or to seek approval of a higher
applicability cutoff.
For sources for which a CTG has not been issued, the
statutory requirements are that RACT be applied to major
stationary sources in moderate and worse ozone nonattainment
areas [Section 182(b)(2)(C)], and ozone transport areas [Section
184(b)(2)2]. Major non-CTG sources in marginal ozone
nonattainment areas may also be subject to RACT [Section
182 (a) (2) (A) ] .
All emissions from 1) non-CTG activities at the source and
2) CTG activities at the source that are below the applicability
cutoff(s) of the RACT regulation(s) for those activities are
included in determining whether the source is major with respect
to these requirements. If a source is major with respect to
these requirements, then RACT must be applied to all of the non-
CTG activities at the source. This means that in the absence of
a CTG for offset lithographic printing, RACT is required to be
applied to offset lithographic printing activities at a source
that is major with respect to Sections 182(b)(2)(C) or Section
184(b)(2). In the absence of a CTG for offset lithographic
printing, RACT may also be required to be applied to offset
lithographic printing activities at a source that is major with
respect to Section 182(a)(2)(A). These requirements apply even
if the offset lithographic printing activities at the source are
not themselves sufficient to be major.
A state may choose to regulate emissions from non-CTG
activities at sources that are not major with respect to Sections
182(b) (2) (C), 184 (b) (2), or 182(a) (2) (A) . This means that in the
absence of a CTG for offset lithographic printing a state may
choose to regulate emissions from offset lithographic printing
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activities at sources that are not major sources with respect to
Sections 182(b) (2) (C), 184 (b) (2), or 182(a) (2) (A) .
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3.0 FOUNTAIN SOLUTION
The draft CTG recommended different levels of VOC (alcohol
or alcohol substitute) content for fountain solution, as used,
for various types of offset printing. These recommendations were
based on information gathered from printers and suppliers, and on
the Maryland state regulation. The State indicated in its
comments that printers have complied with the limits in this
regulation. This comment was confirmed by representatives of two
trade groups for printers in Maryland.
Several commenters suggested that the limits for fountain
solution should allow for greater use of alcohol. No specific
evidence of a widespread need for greater alcohol levels was
presented. Some printers may need and be able to justify higher
limits on a case-by-case basis. Some commenters noted reverse
printing (dark colored ink covers most of substrate with image or
text formed by paper showing through intentional voids in the
dark colored ink) and jobs done with metallic inks as examples of
when it is more difficult to eliminate or reduce the use of
alcohol. The ability to obtain and maintain the proper balance
of ink and fountain solution on an offset lithographic printing
press is a function of many factors including the press,
dampening system, rollers, ink, paper, water quality, and
operator training and skill.
Several commenters suggested that the VOC limit for alcohol
substitutes be 5 weight percent instead of 3 weight percent.
This change makes sense for several reasons. The recommended
limit in the draft CTG for sheet fed printers was 5 weight
percent alcohol (without refrigeration). Emissions from a
fountain solution containing 5 weight percent alcohol substitute
would still be less than at 5 weight percent alcohol because of
the faster evaporation rate (higher volatility) of alcohol. Five
weight percent alcohol substitute is also a practical limit on
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alcohol substitute content for all types of offset printers
because at or above this level ink drying problems will result.
Allowing the use of fountain solutions that contain up to 5
weight percent alcohol substitutes could make it easier for some
printers to eliminate the use of alcohol.
Some sheet-fed printers run their presses with a mix of
alcohol and alcohol substitutes in the fountain solution for
certain jobs. Having a single VOC content limit for sheet-fed
printers for alcohol, alcohol substitutes, or a combination of
the two would simplify compliance demonstrations in these cases.
Several commenters suggested that the definition of alcohol
(as used in fountain solution) include normal propyl alcohol and
ethanol in addition to isopropyl alcohol. We agree with this
comment.
Several commenters also suggested that the baseline level of
alcohol assumed in the model plants on the draft CTG was too
high. The baseline levels assumed were 10 weight percent alcohol
for non-heatset web, 17 weight percent alcohol for heatset web
and sheet-fed, and no alcohol for newspaper. The commenters
suggested that the average/typical level of alcohol used by all
printers still using alcohol was around 10 weight percent, and
also noted that many printers have already eliminated the use of
alcohol. We agree with this comment and note that the reductions
for an individual plant can be estimated, either directly or
using tables in the draft CTG, based on knowledge of the starting
and ending VOC levels in the fountain solution, the type of VOC
used (alcohol or alcohol substitute), and whether the fountain
solution is refrigerated.
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4.0 CLEANING SOLVENTS
The draft CTG recommended a 70 percent reduction in VOC
emissions from cleaning solvents through the use of materials
that, as used, contain no more than 30 weight percent VOC. This
recommendation was based on waterbased cleaners. There are a
number of low VOC cleaners available. These products are both
waterbased and vegetable oil based. The current use of these low
VOC cleaners is limited. They have not been used in all segments
of the offset printing industry. Research, development,
production trials and expanded production use of these materials
continues.
Several commenters suggested that as an alternative to low
VOC cleaning materials, that printers also should have the option
of reducing VOC emissions from cleaning by using cleaning
materials with low vapor pressure. These commenters referred to
the South Coast Air Quality Management District (SCAQMD) Rule
1171 which limits the VOC composite partial vapor pressure of
cleaning materials for offset printing to 25mm Hg at 20°C. (The
definition of VOC composite vapor pressure from the SCAQMD rule
1171 is provided in Appendix A to this document.) Comments from
the SCAQMD suggested that the VOC composite partial vapor
pressure of cleaning materials could be limited to 10mm Hg at
20°C. The VOC composite partial vapor pressure of most cleaning
materials used to meet the SCAQMD requirement is less than 10mm
Hg at 20°C. The VOC composite partial vapor pressure of solvents
used in automatic blanket washing systems is commonly less than
6mm Hg at 20°C. The use of cleaning materials with a VOC
composite partial vapor pressure less than 10mm Hg at 20°C would
result in a comparable emission reduction to using cleaning
materials that contain less than 30 weight percent VOC.
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A new development in the area of cleaning solvents is the
availability of an offset lithographic ink that can be cleaned
with water. This ink was developed by Deluxe Corporation and has
been put in use at over 40 of their facilities since early 1993
in non-heatset web and sheet-fed production printing of checks
and business forms. This ink is being used by other printers in
production printing of greeting cards and brochures. Testing is
being done on applying this ink to other end uses including
heatset web printing.
Several commenters noted that in the draft CTG it was
assumed that 100 percent of the VOC in the cleaning materials
evaporated and was emitted. The comments noted that towels used
for manual cleaning are still wet when cleaning is completed and
that when the towels are kept in a closed container after use
that they are still wet when sent for laundering or disposal
(e.g., burning in a cement kiln). Further, some printers and
some industrial laundries have installed centrifuges (extractors)
to spin solvent out of used shop towels. This recovered solvent
can be reused, distilled, rerefined or combusted. For cleaning
materials with a VOC composite partial pressure less than 10mm Hg
at 20°C about 50 percent of the VOC may remain in the towel after
use. To limit evaporative losses, cleaning materials and used
towels must be kept in closed containers.
In some automatic blanket washing systems, there may be
collection of some of the liquid cleaning materials. An example
would be overspray from the wetting of brushes or rollers.
Clearly any material that is collected as a liquid for reuse or
disposal has not evaporated. Further, the amount of cleaning
material used in automatic blanket washing may be more closely
controlled and may be less than is used in manual cleaning.
There may also be carryover of automatic blanket wash material
into heatset dryers where the carryover material can be
controlled by the same device used to control ink oil emissions
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from the dryer. This is discussed in more detail in the section
below on carryover to heatset dryers.
Several commenters asked that the applicability of the
recommended limits for cleaning materials be clarified. The
limits were intended to apply to blanket and ink roller washes.
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5.0 CARRYOVER TO HEAT SET DRYERS
Several commenters noted that there was no mention in the
draft CTG of the carryover of VOC from cleaning solvents and
fountain solutions into heatset dryers. These comments focused
on carryover of cleaning solvent from automatic blanket washing
and alcohol substitutes from fountain solution. Carryover is
important because the same control device that reduces ink oil
emissions from the dryer exhaust can also control cleaning
solvents and fountain solution materials that are exhausted from
the dryer.
The first evidence of carryover of VOC from automatic
blanket washing systems was fires and explosions in dryers.
These resulted from a build-up of VOC from the cleaning solvents.
A great deal of safety planning and engineering now goes into the
design and operation of automatic blanket washing systems to
prevent such incidents.
Determination of the amount or fraction of blanket wash or
fountain solution VOC that is exhausted from the dryer is
difficult because of the relatively low ratio of the amount of
VOC from blanket wash and fountain solution (particularly when
alcohol substitutes are used in the fountain solution) to the
amount of VOC from ink oil VOC that evaporates in the dryer. The
results of some tests were submitted in response to the draft
CTG. These tests indicated that a considerable portion of the
VOC from cleaning solvents used in automatic blanket washing
systems and from alcohol substitutes used in fountain solution
can be captured in and exhausted from the dryer.
For automatic blanket washing, direct capture in each of two
separate tests at different facilities averaged around 40
percent. Direct capture refers to the fraction of the VOC used
in the blanket wash that is carried into the dryer on the web
(printed substrate) immediately after the blanket wash. The
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automatic blanket wash materials used in both tests all had vapor
pressures less than 10mm Hg at 20°C.
In the first test, a limited number of measurements were
made on a production press at a printing facility. In the second
test over 100 measurements were made under various press, dryer
and automatic blanket washer operating conditions on a production
size press at a pressmakers facility. Since there were a large
number of runs at a variety of operating conditions in the second
test and the results from the two tests were similar, 40 percent
direct carryover of VOC from automatic blanket washing is a
reasonable general assumption when the vapor pressure of the
cleaning material is less than 10mm Hg at 20°C.
In the test conducted at a printing facility, a separate
measurement was made of indirect capture. This refers to VOC
from blanket washing that is first dispersed in the pressroom air
and subsequently drawn into the dryer through the make-up air
inlets over a long period of time. This VOC enters the pressroom
air in various ways including as overspray from the process of
wetting the cloth that wets and cleans the blanket, and from
evaporation from the cloth over a period of time. In this test
almost 40 percent of the VOC in the blanket wash material was
found to be indirectly captured in the dryer. Since test
results on indirect capture were presented for just one facility
at its particular operating conditions and the amount of indirect
capture would be affected by press and pressroom ventilation
practice, no general assumption is made in this document about
indirect carryover of VOC from automatic blanket wash materials.
For fountain solution, direct capture of VOC from alcohol
substitutes was measured at a variety of operating conditions on
the production size press at the pressmakers facility. The
average result was about 70 percent direct capture. Since there
were a large number of runs at a variety of operating conditions
in the fountain solution test, 70 percent direct carryover of VOC
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from alcohol substitutes in fountain solution is a reasonable
general assumption.
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6.0 COMPLIANCE DEMONSTRATION
6.1 FOUNTAIN SOLUTION
Several commenters suggested changes in the recommendations
for compliance demonstration and monitoring for fountain
solution.
The fountain solution on most presses flows through a
recirculating system. A system may be dedicated to a single unit
on a press, service an entire press, or even provide fountain
solution to multiple presses. A recirculating system includes a
tank (reservoir), pump(s), pipes or tubes, and a tray for each
unit served by the system. (On smaller presses, fountain
solution may be fed to the tray from a bottle, without
recirculation.) A roller picks up fountain solution from the
tray and delivers some of it via a series of rollers and
sometimes a brush to the printing plate.
On some presses the only material added to the recirculating
system is press ready fountain solution. In these cases, knowing
that the VOC content of each addition of press ready material to
the recirculating system is within the VOC content limit is
sufficient to know that the material on press (i.e., in the
recirculating system) is also within the VOC content limit.
The VOC content of press ready material can be determined
analytically from a sample taken before it is added to the
recirculating system, or by having analytical data for the
constituents of the press ready mix and combining the results
based on the proportions in which they are mixed to make press
ready material. The analysis of the constituents of the press
ready mix can be performed by the supplier of each constituent.
On some presses there are times when VOC containing
materials other than press ready fountain solution (e.g., alcohol
or VOC containing alcohol substitute concentrate) are added
directly to the material already in the recirculating system.
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These direct additions may be made automatically or manually. In
these cases some information is needed about the VOC content of
the material in the recirculating system after the direct
addition is made to check that the material on press is still
within the VOC content limit.
After an automatic addition is made, the check on the VOC
content of the on press material could be based on the control
settings of the automatic feed equipment which makes additions of
VOC containing ingredients up to a pre-set level. The equipment
used to make automatic additions would have to be operated
properly, and records would have to be kept to document that the
calibration of the equipment was checked periodically.
Alternatively, a sample can be taken from the recirculating
system. This sample can either be analyzed directly for VOC
content or analyzed with an instrument such as a hydrometer,
refractometer or conductivity meter that has been calibrated
against the VOC content limit for the fountain solution and some
lower VOC content [e.g., no VOC (i.e., the water used in the
fountain solution), the desired VOC content, or some point in
between] and verifying that the reading for the on press material
is in the proper range.
After a manual addition is made, the check on the VOC
content of the on press material can be made using the same
sampling and analysis procedure described above for automatic
additions. Alternatively, if the quantity and VOC content of the
material on press before the addition is known, then the VOC
content of the material on press after the addition can be
calculated by combining the before addition information with the
quantity and VOC content of the material added.
6.2 METHODS 25 AND 25A
Several commenters noted that the information in the draft
CTG concerning when to use Method 25 and when to use Method 25A
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for compliance testing of control devices on heatset dryers was
not consistent with the latest guidance from EPA on this subject.
We agree with this comment. We agree that the latest guidance
should be used. A copy of the latest guidance from EPA (October
25, 1993 memorandum from John B. Rasnic, Director, Stationary
Source Compliance Division) is in Appendix B of this document.
6.3 METHODS 24 AND 24A
Several commenters asked that the EPA clarify that Method
24, not Method 24A, is the test method that should be used to
determine the VOC content of materials (inks, coatings, fountain
solution additives and cleaning solvents) used by offset
lithographic printers. We agree with this comment. The only
situation for which the EPA has required or recommended that
Method 24A be used is for publication rotogravure printing.
6.4 EMISSION LIMITATIONS AND MATERIAL TESTING
The emission limits recommended in the draft CTG or
discussed in this document for fountain solution and cleaning
materials are intended to limit the amount of VOC (or vapor
pressure for cleaning materials) in these types of materials as
they are used on the press (as applied). They were not intended
to be limit the amount of VOC (or vapor pressure for cleaning
materials) in the concentrates (as supplied) that are shipped
from the supplier or distributor to the printer. Fountain
solution concentrates, especially alcohol substitutes, are
diluted with large amounts of water (e.g., a few ounces of
concentrate per gallon of water) to make press ready fountain
solution. Some cleaning materials may also be diluted with water
before use on the press.
The amount of VOC in a press ready fountain solution or
material can be determined directly by analysis of the press
ready material, or from analytical data for the constituents of
the press ready material combined in the proportions in which
they are mixed to make press ready material. The analysis of the
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constituents of the press ready material can be performed by the
supplier of each constituent and provided to the printer. The
principles discussed in the EPA document Procedures for
Certifying Quantity of Volatile Organic Compounds Emitted by
Paint, Ink and Other Coatings (EPA-450/3-84-019 as revised June
19, 1986) may be helpful to suppliers and printers in calculating
"as applied" VOC contents from "as supplied" analytical VOC
content data and mix ratios.
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APPENDIX A
DEFINITION OF VOC COMPOSITE
PARTIAL VAPOR PRESSURE
FROM
SOUTH COAST AIR QUALITY MANAGEMENT DISTRICT
RULE 1171
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!35) VOC COMPOSITE PARTIAL PRESSURE is the sum of the partial
pressures of the compounds defined as VOC's.
VOC Composite Partial Pressure is calculated as follows:
(W.) (VP.) /MW.
PP ='
c
W W -L W
MW MW i~ MW.
w e ^ x i
Where:
W± = Weight of the "i"th VOC compound, in grams
Ww = Weight of water, in grams
We = Weight of exempt compound, in grams
MW± = Molecular weight of the "i"th VOC compound, in g_
g-mole
MWW = Molecular weight of water, in g
g-mole
MWe = Molecular weight of exempt compound, in g
g-mole
PPC = VOC composite partial pressure at 20°C, in mm Hg
VP± = Vapor pressure of the "i"th VOC compound at 20°C,
in mm Hg
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APPENDIX B
OCTOBER 25, 1993 GUIDANCE
ON METHODS 25 AND 25A
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October 25, 1993
MEMORANDUM
SUBJECT: EPA's VOC Test Methods 25 and 25A
FROM: John B. Rasnic, Director
Stationary Source Compliance Division
Office of Air Quality Planning and Standards
TO: Air, Pesticides, and Toxics Management Division
Directors
Regions I and IV
Air and Waste Management Division Director
Region II
Air, Radiation, and Toxics Division Director
Region III
Air and Radiation Division Director
Region V
Air, Pesticides, and Toxics Division Director
Region VI
Air and Toxics Division Directors
Regions VII, VIII, IX and X
As a result of requests from industry, Regional Offices and
State programs, we have reviewed our guidance regarding the use of
Methods 25 and 25A for measuring gas stream volatile organic
compounds (VOC) concentration. Information obtained during this
review has resulted in the following revised guidance, which is
effective immediately and which supersedes all previous guidance
on this matter. This revision has been coordinated with the other
divisions within the Office of Air Quality Planning and Standards.
The EPA has decided to add an option 3 to permit further the
use of Method 25A in lieu of Method 25 under certain conditions.
Therefore, our new guidance is as follows. The EPA mandates the
use of Method 25 for measuring gas stream VOC concentration when
determining the destruction efficiency (DE) of afterburners. It
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also allows the use of Method 25A, in lieu of Method 25, under any
of the following circumstances: 1) when the applicable regulation
limits the exhaust VOC concentration to less than 50 ppm; 2) when
the VOC concentration at the inlet of the control system and the
required level of control are such to result in exhaust VOC
concentrations of 50 ppm or less; or 3) if, because of the high
efficiency of the control device, the anticipated VOC
concentration at the control system exhaust is 50 ppm or less,
regardless of the inlet concentration.
Further, if a source elects to use Method 25A under option 3,
above, the exhaust VOC concentration must be 50 ppm or less and
the required DE must be met for the source to have demonstrated
compliance. If the Method 25A test results show that the required
DE apparently has been met, but the exhaust concentration is above
50 ppm, this is an indicator that Method 25A is not the
appropriate test method and that Method 25A should be used.
BACKGROUND
The primary industry impacted by this policy is the printing
industry, which has consistently claimed that the Method 25 test
procedure is too expensive and cumbersome to be used as a
compliance demonstration tool. They have stated that current
state-of-the-art-technology afterburners routinely achieve 98-99
percent destruction efficiency, generally significantly greater
than is required by regulations. As a result, control system
outlet VOC concentrations are commonly less than 50 ppm,
regardless of the inlet concentration.
Regulations which specify performance requirements for the
subject control systems have typically been based on older
technology, which was less efficient than current technology. We
agree with the printing industry's claim that VOC destruction
technology currently available can perform at greater levels than
as specified by the regulations. It is therefore appropriate to
revise our guidance on the usage of these compliance demonstration
methods.
This guidance specifies the circumstances under which
Method 25 and Method 25A are to used. It will reduce the
administrative burden on a significant number of regulated
industrial sources but will not reduce the stringency of any
currently applicable regulatory requirements.
cc: OAQPS Division Directors
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