EPA-453/P-06-001 (August 1, 2006)
Control Techniques Guidelines:
Industrial Cleaning Solvents
(DRAFT)
U.S. Environmental Protection Agency
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ui Air v^umny rimming aiiu oiaiiua
Sector Policy and Programs Division
Research Triangle Park, NC 27711
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Table of Contents
Parts.
1.0 Background and Control Options
2.0 Appendix A: 1994 ACT on Industrial Cleaning Solvents
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DRAFT CTG for Industrial Cleaning Solvents, Docket No. EPA-HQ-OAR-2006-0535 - 08/01/06
I. Introduction
Clean Air Act (CAA) section 172(c)(l) provides that state implementation plans
(SIPs) for nonattainment areas must include "reasonably available control measures"
(RACM), including "reasonably available control technology" (RACT), for sources of
emissions. Section 182(b)(2) provides that for certain nonattainment areas, States must
revise their SIPs to include RACT for sources of VOC emissions covered by a control
techniques guidelines (CTG) document issued after November 15,1990 and prior to the
area's date of attainment.
The United States Environmental Protection Agency (EPA) defines RACT as "the
lowest emission limitation that a particular source is capable of meeting by the
application of control technology that is reasonably available considering technological
and economic feasibility." 44 FR 53761 (Sept. 17, 1979). In subsequent Federal
Register notices, EPA has addressed how states can meet the RACT requirements of the
Act.
CAA section 183(e) directs EPA to list for regulation those categories of products
that account for at least 80 percent of the VOC emissions, on a reactivity-adjusted basis,
from consumer and commercial products in areas that violate the NAAQS for ozone (i.e.,
ozone nonattainment areas). EPA issued the list on March 23, 1995, and has revised the
list periodically. See 60 FR 15264 (March 23, 1995); see also 71 FR 28320 (May 16,
2006), 70 FR 69759 (Nov. 17, 2005); 64 FR 13422 (Mar. 18, 1999). Industrial cleaning
solvents are included on the current section 183(e) list.
This draft CTG is intended to provide state and local air pollution control
authorities information that should assist them in determining RACT for volatile organic
compounds (VOCs) for industrial cleaning solvents. In developing this CTG, EPA,
among other things, evaluated the sources of VOC emissions from the use of industrial
cleaning solvents and the available control approaches for addressing these emissions,
including the costs of such approaches. Based on available information and data, EPA
provides recommendations for RACT for industrial cleaning solvents. EPA solicits
comment on all aspects of this draft document.
Once finalized, States can use the recommendations in this CTG to inform their
own determination as to what constitutes RACT for VOC for industrial cleaning solvents
in their particular nonattainment areas. The information contained in this document is
provided only as guidance. This guidance does not change, or substitute for, applicable
sections of the CAA or EPA's regulations; nor is it a regulation itself. This document
does not impose any legally binding requirements on any entity. It provides only
recommendations for state and local air pollution control agencies to consider in
determining RACT. State and local pollution control agencies are free to implement
other technically-sound approaches that are consistent with the CAA and EPA's
implementing regulations
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DRAFT CTG for Industrial Cleaning Solvents, Docket No. EPA-HQ-OAR-2006-0535 - 08/01/06
The recommendations contained in this draft CTG are based on the data and
information currently available to EPA. These general recommendations may not apply
to a particular situation based upon the circumstances. Regardless of whether a State
chooses to implement the recommendations contained herein through State rules, or to
issue State rules that adopt different approaches for RACT for VOCs from industrial
cleaning solvents, States must submit their RACT rules to EPA for review and approval
as part of the SIP process. EPA will evaluate the rules and determine, through notice and
comment rulemaking in the SIP process, whether they meet the RACT requirements of
the Act and EPA's regulations. To the extent a State adopts any of the recommendations
in this guidance into its State RACT rules, interested parties can raise questions and
objections about the substance of this guidance and the appropriateness of the application
of this guidance to a particular situation during the development of the State rules and
EPA's SIP approval process.
CAA section 182(b)(2) provides that a CTG issued after November 15, 1990 and
before the date of attainment must include the date by which States must submit SIP
revisions in response to the CTG. States subject to section 182(b) should submit their
SIP revisions within one year of the date of issuance of the final CTG for industrial
cleaning solvents. States subject to CAA section 172(c)(l) may take action in response
to this guidance, as necessary to attain.
The remainder of this document is divided into six sections. Section II provides
the Background and Overview, which lists the cleaning (unit) operations associated with
industrial cleaning solvents and identifies the sources of VOC emissions from those
cleaning operations. Section III describes the emissions threshold that applies to this
draft CTG. Section IV describes the available control options for addressing VOC
emissions and summarizes state and local regulatory approaches for addressing such
emissions. It also lists categories of industries for exclusion from the draft CTG. (A
summary of the state and local regulatory approaches that EPA surveyed in preparing this
draft document will be placed in the docket in the form of a memo. This information
supplements the survey of state CTG summarize in Appendix B of the 1994 ACT). The
fourth section provides our proposed recommendations for RACT for industrial cleaning
solvents. Section V discusses the cost-effectiveness of the recommended controls.
Section VI provides a list of references.
II. Background and Overview
This category of consumer and commercial products includes the industrial
cleaning solvents used by many industries. It includes a variety of products that are used
to remove contaminants such as adhesives, inks, paint, dirt, soil, oil, and grease.
Contaminants are removed from parts, products, tools, machinery, equipment, vessels,
floors, walls, and other work production related work areas for a variety of reasons
including safety, operability, and to avoid product contamination. The cleaning solvents
used in these (unit) operations are, in many cases, generally available bulk solvents that
are used for a multitude of applications not limited to cleaning. For example, petroleum
distillates may be used as a cleaning solvent, as a paint thinner, or as an ingredient used
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DRAFT CTG for Industrial Cleaning Solvents, Docket No. EPA-HQ-OAR-2006 -0535 - 08/01/06
in the manufacture of a coating, such as paint. Because a portion of all solvents evaporate
during use, such solvent-based cleaning materials result in large amounts of emissions of
VOC.
In 1994, EPA completed a study of industrial cleaning solvents that characterized
cleaning operations carried out within six focus industries (automotive, electrical
equipment, magnetic tape, furniture, packaging, and photographic supplies) to evaluate
sources of evaporative emissions from VOC solvents used as cleaning materials. (See
Reference 1 in the reference section for the citation to this document). We believe that
the range of cleaning activities performed in these focus industries provide a good variety
of cleaning operations for the study, and that the information obtained relevant to VOC
emission sources and possible control techniques can be applied to virtually any industry.
Data collected by EPA during the development of the 1994 Alternative Control
Techniques (ACT) (to be referred to as 1994 ACT or ACT) document for industrial
cleaning solvents show nationwide usage of VOC solvent from six industries studied is
more than 360,000 Mg/yr (400,000 tpy).1 We also reported in the ACT document that the
estimated total VOC solvent usage for cleaning by all U.S. industry was more than
910,000 Mg/yr (1 million tpy). This number was estimated using multiple sources,
including data from the facilities we surveyed. In general, VOC emissions occur from
industrial cleaning solvents through evaporation during cleaning activities such as
wiping, flushing, and brushing, as well as from storage and disposal of used shop towels
and solvent.
The 1994 ACT is included as Appendix A to this draft CTG. The document
provides a thorough discussion of cleaning activities and types of cleaning operations in a
wide and diverse assortment of industrial facilities, frequently used cleaning solvents, and
the practices (or lack of) for managing solvents. It, also, identifies a methodology for
estimating VOC emissions by cleaning operation, discusses control techniques for
addressing such emissions, the costs-benefits of setting up a solvent accounting and
management system, and other items.
EPA surveyed 34 facilities in the six focus industries and collected approximately
300 individual cleaning data sets or unit operation systems (UOS) representing emissions
from the nine types of cleaning unit operations (UO) in the focus industries for the ACT
document. These nine UO are identified below together with the VOC emission
distribution based on the UOS material balance data:
Spray Gun Cleaning (50 percent)
Spray Booth Cleaning (14 percent)
Large Manufactured Components Cleaning (14 percent)
Parts Cleaning (7.0 percent)
Equipment Cleaning (6.9 percent)
Line Cleaning (3.6 percent)
Floor Cleaning (2.9 percent)
Tank Cleaning (0.82 percent)
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Small Manufactured Components Cleaning (0.44 percent).
Because spray gun cleaning (one of the UO) accounted for 50 percent of the
emissions from cleaning operations, the ACT dedicated appendix G of the document to
describe procedures for determining, in a consistent way, VOC emissions from a number
of subcategories of spray gun cleaning. The subcategories represented the range of gun
cleaning practices in the focus industries in 1994. However, due to the availability of
enclosed gun cleaners today, states have disallowed gun cleaning methods that result in
high solvent emissions.
The purpose of identifying these UO is to assist State and local agencies in
identifying the sources of VOC emissions from cleaning activities and to provide a
structure for developing and applying control techniques to mitigate VOC emissions from
industrial cleaning solvents used in these UO. And from this study, EPA believes all
categories of industrial cleaning operations are represented.
The ACT document provided a quantitative overview of cleaning solvents used
and a model for accounting and tracking solvent usagea solvent management system. It
also provided a methodology for calculating emissions in a consistent way.
Although the industrial cleaning solvent product category includes a variety of
different products with differing VOC contents, and although these products are used in
different ways by a wide range of industries, we believe that there are two basic
approaches to achieve VOC emission reductions from this product category. First, the
users of the products can control emissions through work practices targeted at the
activities and sources of emissions specific to the user's industry (e.g., keeping solvent
containers covered, properly storing and disposing of used shop towels and solvent, etc.).
Second, users can reduce overall VOC emissions through solvent substitution (e.g., use of
low-VOC, no-VOC, or low-vapor pressure solvents). These two general approaches are
effective strategies to achieve significant emission reductions from this product category,
notwithstanding the variation in the products, their users, and their specific uses.
We are considering including an example rule when we finalize this draft CTG
that would incorporate the recommendations contained in the final CTG. We solicit
comments on the utility of such an example rule in the final CTG.
III. Applicability (Scope of Sources')
In the draft CTG, EPA recommends that, in general, the recommendations in this
CTG should have broad applicability to any industrial cleaning operations that have
VOC emissions of at least 6.8 kg/day (15 Ib/day), before controls. This level of
emissions has been the applicability threshold for many CTGs in the past. Furthermore,
it is consistent with the intent of CAA section 183(e) to address individually small uses of
consumer and commercial products that, in the aggregate, are significant sources of VOC
emissions. We recommend that, for purposes of determining this threshold, aggregate
emissions from all solvent cleaning activities associated with covered operations at a
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given facility are included. As described below, we also recommend that specific
industry category exclusions, similar to the ones provided for in the Bay Area and South
Coast rules but tailored to the States' individual situations, accompany the applicability
threshold.
In addition to the exclusions a State or local agency may specify as a result of the
existence of effective measures that address cleaning operations associated with specific
source categories within its jurisdiction, we recommend that the States exclude from
applicability those cleaning operations in the following categories listed for regulation
under CAA section 183(e): aerospace coatings, wood furniture coatings, shipbuilding
and repair coatings, flexible packaging printing materials, lithographic printing materials,
letterpress printing materials, flat wood paneling coatings, large appliance coatings, metal
furniture coatings, paper film and foil coating, plastic parts coatings, miscellaneous
metals parts coatings, fiberglass boat manufacturing materials, miscellaneous industrial
adhesives, and auto and light-duty truck assembly coatings. For three of these product
categories (i.e., aerospace coatings, wood furniture coatings, and shipbuilding and repair
coatings), EPA has already issued CTGs that address cleaning operations. For the
remaining categories, EPA intends to include control measures for cleaning associated
with these categories if the Agency determines that a CTG is appropriate for the
respective categories.
We estimate that there are approximately 7360 facilities in nonattainment areas
for 8-hour ozone standards of which about 2550 would be potentially affected because
they meet the 6.8 kg/day (15 Ib of VOC /day) applicability threshold for this draft CTG.
We derived these number based on available information concerning the use of industrial
cleaning solvents from the 2002 EPA National Emissions Inventory.
IV. Recommended Control Options
The recommended measures for controlling emissions of VOC from the use,
storage, and disposal of industrial cleaning solvents includes work practices, limitations
on VOC content of the cleaning materials, and an optional alternative limit on composite
vapor pressure of the cleaning materials. The first two recommendations are based on the
Bay Area AQMD rule. Following the recommended control measures section is a
discussion of recommended exclusions from applicability of these measures that should
be considered by the State and local agencies.
When developing RACT measures for industrial cleaning operations, we suggest
that State and local agencies consider the specific industries and operations in their
jurisdictions and the individual requirements of those operations and tailor their rules to
those specific scenarios accordingly. Furthermore, in considering existing cleaning
requirements as bases for specific exemptions from their general industrial cleaning
solvents rules, State and local agencies should take into account how current those
measures are. EPA believes that more recent rules are likely to be more effective than
older, possibly outdated, rules. We remind States that the determination of whether a
specific State or local measure meets the RACT requirements of the Act will occur
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during the notice and comment rulemaking process associated with EPA action on SIP
submissions.
A. Control Measures
1. Work Practices
Recommended work practices that will help reduce VOC emissions from the use,
handling, storage, and disposal of cleaning solvents and shop towels include:
Covering open containers and used applicators;
Minimizing air circulation around cleaning operations;
Properly disposing of used solvent and shop towels; and
Implementing equipment practices that minimize emissions (e.g., keeping
parts cleaners covered, maintaining cleaning equipment to repair solvent leaks,
etc.).
2. VOC Content Limit
We recommend a generally applicable VOC content limit of 50 grams VOC per
liter (0.42 Ib/gal) of cleaning material for each of the nine cleaning UO identified in the
Background and Overview section, unless emissions are controlled by an emission
control system with an overall control efficiency of at least 85 percent. This limit is
modeled on the "general use" category of the Bay Area AQMD solvent cleaning
regulations, taking into account the specific exclusions provided for in the Bay Area
AQMD rule and described below.
3. Alternative Composite Vapor Pressure Limit
In addition to the recommended VOC content limit, EPA is considering possible
inclusion of a composite vapor pressure limit of 8 millimeters of mercury (mmHg) at 20
degrees Celsius, as (1) a replacement for the 50 g/1 VOC content limit entirely; or (2) an
alternative limit that may be used in lieu of the 50 g/1 VOC content limit for specific
operations as determined by the State or local agency. We recommend that such a limit
be considered for each of the nine cleaning UO identified in the Background and
Overview section.
B. Exclusions
This section includes product categories that EPA has listed for regulation under
section 183(e) as well as categories of cleaning operations that are specifically excluded
from applicability in the Bay Area rule. The Bay Area exclusions are provided as
examples for consideration by the State and local agencies.
1. Categories Listed for Regulation under CAA Section 183(e)
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DRAFT CTG for Industrial Cleaning Solvents, Docket No. EPA-HQ-OAR-2006 -0535 - 08/01/06
We recommend that the States exclude from applicability those cleaning
operations in the following categories listed for regulation under CAA section 183(e):
Aerospace coatings
Wood furniture coatings
Shipbuilding and repair coatings
Flexible packaging printing materials
Lithographic printing materials
Letterpress printing materials
Flat wood paneling coatings
Large appliance coatings
Metal furniture coatings
Paper film and foil coating
Plastic parts coatings
Miscellaneous metals parts coatings
Fiberglass boat manufacturing materials
Miscellaneous industrial adhesives
Auto and light-duty 'truck assembly coatings
2. Categories with Specific Exemptions under Bay Area 8-4-116
Electrical and electronic components
Precision optics
Numismatic dies
Stripping of cured inks, coatings, and adhesives
Cleaning of resin, coating, ink, and adhesive mixing, molding, and
application equipment
Research and development laboratories
Medical device or pharmaceutical manufacturing
Performance or quality assurance testing of coatings, inks, or adhesives
3. Categories Subject to Specific Rules and Exemptions under Bay Area 8-4-
117
Architectural coating
Metal container, closure, and coil coating
' Paper, fabric, and film coating
Light and medium duty motor vehicle assembly plants
Surface coating of metal furniture and large appliances
Surface coating of miscellaneous metal parts and products
Graphic arts printing and coating operations
Coating of flat wood paneling and wood flat stock
Magnet wire coating operations
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Aerospace assembly and component coating operations
Semiconductor wafer fabrication operations
Surface coating of plastic parts and products
Wood products coating
Coating, ink, and adhesive manufacturing
Flexible and rigid disc manufacturing
Marine vessel coating
Motor vehicle and mobile equipment coating operations
Polyester resin operations
4. Categories with special limits in South Coast AQMD Rule 1171(c) and
exemptions in 1171(h)
In addition to the Bay Area exclusions, and as discussed earlier, the more
stringent South Coast AQMD "general use" limit of 25 g/1 (0.21 Ib/gal) is accompanied
by higher limits for several individual operations. Although we are not recommending
higher limits for these categories beyond the 50 g/1 limit in this CTG, State and local
agencies should be aware of the individual performance requirements in these categories
when developing individual State or local cleaning solvent rules based on the specific
industries within their jurisdictions. We suggest that State and local agencies refer to the
South Coast rule for more details on subcategories and specific limits. The broad
categories are:
Product cleaning during manufacturing process or surface preparation for
coating
Repair and maintenance cleaning
Cleaning of coatings or adhesives application equipment
Cleaning of ink application equipment
Cleaning of polyester resin application equipment
V. Impacts of Recommended Controls
EPA estimates that there are approximately 2,550 facilities in ozone
nonattainment areas that would be affected by the draft CTG. These facilities had
emissions that exceed the emission threshold of 6.8 kg (15 Ib) of VOC per day. Total
aggregate VOC emissions from solvent cleaning operations from these nonattainment
sources are approximately 64,000 Mg/yr (71,000 tpy). EPA used studies published by
the Bay Area AQMD to estimate the cost of compliance for the measures recommended
in the draft CTG. According to these estimates, EPA believes that affected sources may
either incur minimal additional costs or realize a savings on a case - by - case basis,
depending primarily on facts such as how much they currently spend to operate high-
VOC content solvent - based parts cleaners, and the cost of organic solvent disposal. The
Bay Area AQMD studies indicate that there is a cost savings associated with replacing
high-VOC cleaning materials with low-VOC, waterbased cleaning materials.
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The total VOC emissions from solvent cleaning operations (64,000 Mg/yr (71,000
tpy) were determined by first assigning the VOC emissions from solvent cleaning
operations at each facility (NEI database) to one of two general groups: parts cleaners,
and other solvent cleaning operations. The parts cleaner subgroup included emissions
from all SCC codes with a "degreasing" or cold solvent cleaning/stripping classification
in SCC_L3. VOC emissions from this subcategory are approximately 4,000 Mg/yr
(4,400 tpy). The other solvent cleaning operations included all other SCCs that were
identified as solvent cleaning operations. The VOC emissions from the other subgroup
are approximately 60,000 Mg/yr (66,000 tpy). These emissions do not include emissions
from halogenated parts cleaners.
Costs associated with switchover to aqueous parts cleaners (cleaning systems or
washers) include the initial cost of equipment, solvent costs, filters, electricity, and waste
disposal costs. Many of these costs are also incurred when operating higher VOC solvent
cleaners. A study on parts cleaners, for example, has shown typical annual costs for
mineral spirits parts cleaners as $1,453. Estimates on annual costs for aqueous parts
cleaners, in comparison, range from $1,171 to $1,480, thus showing that facilities could
either face a slight increase in cleaning costs or realize a cost savings as a result of the
switchover.6
Facilities may either incur minimal additional costs or realize a savings on a case-
by-case basis, depending primarily on how much they currently spend to operate the high
VOC content solvent-based parts cleaners, the cost of organic solvent disposal, and air
emission fees levied for VOC emissions. A study provided by the California Bay Area
AQMD shows that the cost-effectiveness for meeting the 50 grams of VOC per liter of
cleaning material limit for a parts cleaner is estimated at $l,832/Mg (1,664/ton).6'7 This
represents the annual cost of compliance (industry wide) for parts cleaners (Table 4 of the
Bay Area Regulation 8, Rule 16). We determined that replacing high VOC content
cleaning materials with low VOC water-based cleaning materials for the other cleaning
(unit) operations (e.g., cleaning of large manufactured surfaces, tank cleaning, and gun
cleaning, etc.) would result in an estimated cost savings of $l,460/Mg. For this
calculation we only considered the cost-difference in cleaning material cost and cost-
difference in waste disposal cost. The savings is a result of the lower cost of aqueous
cleaners which offset the increase in waste disposal cost for aqueous cleaners.
As explanined above, this draft CTG is guidance for the States to use in
determining RACT for VOC from industrial cleaning solvents. State and local pollution
control agencies are free to implement other technically-sound approaches for RACT that
are consistent with the CAA and EPA's implementing regulations. Accordingly, there is
necessarily some uncertainty in any prediction of costs and emission impacts associated
with the recommendations in this document. Nevertheless, assuming that States adopt
the recommendations in this draft CTG or comparable approaches, EPA anticipates a net
cost savings. We based this prediction on an assumption that substitution of low-VOC
materials for high-VOC materials is possible for all uses. Because this assumption is not
true for some applications, this prediction may not be valid in all cases.
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VI. References
1. U.S. Environmental Protection Agency, Alternative Control Techniques
DocumentIndustrial Cleaning Solvents, February 1994. EPA-453/R-94-015.
(NTISPB 94-181-694).
2. Bay Area Air Quality Management District, Regulation 8, Rule 16: Solvent
Cleaning Operations, http:// www.arb.ca.gov/DRDB/BA/CURHTML/R8-
16.PDF , (Accessed June 27, 2006).
3. South Coast Air Quality Management District, Rule 1171: Solvent Cleaning
Operations.
4. Sacramento Metropolitan Air Quality Management District, Rule 466: Solvent
Cleaning.
5. U.S. Environmental Protection Agency, Control of Volatile Organic Emissions
from Solvent Metal Cleaning, November 1977. EPA-450/2-77-022.
6. Bay Area Air Quality Management District, Staff Report: Proposed
Amendments to BAAQMD Regulation 8, Rule 16: Solvent Cleaning Operations,
September 2002.
7. South Coast Air Quality Management District, Staff Report for
ProposedAmendment to Rule 1171 - Solvent Cleaning Operations, August 15,
1996.
10
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EPA-453/P-06-001
August 1,2006)
Place holder for
APPENDIX A
1994 Control Techniques Guidelines: Industrial Cleaning Solvents
(DRAFT)
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TECHNICAL REPORT DATA
(Please read Instructions on reverse before completing)
1. REPORT NO.
EPA-453/P-06-001
4. TITLE AND SUBTITLE
2.
Control Techniques Guidelines: Industrial Cleaning Solvents
(DRAFT)
7. AUTHOR(S)
9. ASSISTING ORGANIZATION NAME AND ADDRESS
Eastern Research Group, Inc. (ERG)
1600 Perimeter Park Drive,
Morrisville, NC 27560
Suite 200
12. SPONSORING AGENCY NAME AND ADDRESS
Director
Office of Air Quality Planning and Standards
Office of Air and Radiation
U.S. Environmental Protection Agency
Research Triangle Park, NC 2771 1
3. RECIPIENTS ACCESSION NO.
5. REPORT DATE
August 1, 2006
6. PERFORMING ORGANIZATION CODE
8. PERFORMING ORGANIZATION REPORT NO.
10. PROGRAM ELEMENT NO.
1 1 . CONTRACT/GRANT NO.
68-D-0 1-078
13. TYPE OF REPORT AND PERIOD COVERED
Draft
14. SPONSORING AGENCY CODE
1
15. SUPPLEMENTARY NOTES
EPA Work Assignment Manager : Dr. Mohamed Serageldin
16. ABSTRACT
Clean Air Act (CAA) section 172(c)(l) provides that state implementation plans (SIPs) for
nonattainment areas must include "reasonably available control measures" (RACM), including
"reasonably available control techniques" (RACT), for sources of emissions. Section 182(b)(2)
provides that for certain nonattainment areas, States must revise their SIPs to include RACT for sources
of VOC emissions covered by a control techniques guidelines document (CTG) issued after November
15, 1990 and prior to the area's date of attainment
This draft CTG is intended to provide state and local air pollution control authorities information that
should assist them in determining RACT for industrial cleaning solvents. The Agency is requesting
comments on the recommended control options.
17.
a. DESCRIPTORS
KEY WORDS AND'DOCUMENT ANALYSIS
b. IDENTIFIERS/OPEN ENDED TERMS c. COSATI Field/Group
VOC, Cleaning solvents, Control techniques Cleaning Solvents, Air pollution
guidelines, Nonattainment areas, Volatile controls, Pollution prevention,
organic compounds, Ozone
18. DISTRIBUTION STATEMENT
Release Unlimited
19. SECURITY CLASS (Report) 21. NO. OF PAGES
Unclassified
20. SECURITY CLASS (Page) 22. PRICE
Unclassified
EPA Form 2220-1 (Rev. 4-77) PREVIOUS EDITION IS OBSOLETE
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EPA-453/P-06-001
August 1,2006)
APPENDIX A of Draft CTG
1994 Control Techniques Guidelines: Industrial Cleaning Solvents
(DRAFT)
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Untied Statea Office of Mr Quality
Environment*! Protection Planning and Standard*
Agency Research Triangle Park NC 27711
EPA-4S3/R-94-015
February 1994
Mr
*EPA Alternative .Control
Techniques Document--
Industrial Cleaning Solvents
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EPA-453/R-94-015
Alternative Control
Techniques Document--
Industrial Cleaning Solvents
Emission Standards Division
U. S. Environmental Protection Agency
Emission Standards Division
Research Triangle Park, NC 27711
February, 1994
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ALTERNATIVE CONTROL TECHNIQUES DOCUMENTS
This report is issued by the Emission Standards Division,
Office of Air Quality Planning and Standards, U. S. Environmental
Protection Agency, to provide information to State and local air
pollution control agencies. Mention of trade names and
commercial products is not intended to constitute endorsement or
recommendation for use. Copies of this report are available--as
supplies permit--from the Library Services Office (MD-35),
U. S. Environmental Protection Agency, Research Triangle Park,
North Carolina 27711 ([919] 541-2777) or, for a nominal fee, from
the National Technical Information Service, 5285 Port Royal Road,
Springfield, VA 22161 ([800] 553-NTIS).
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TABLE OF CONTENTS
Page
1.0 EXECUTIVE SUMMARY ................. 1-1
2.0 INTRODUCTION .................... 2-1
3.0 INDUSTRIAL CLEANING WITH ORGANIC SOLVENTS ..... 3-1
3.1 OVERVIEW OF CLEANING ............. 3-2
3.1.1 Cleaning Mechanisms . ......... 3-2
3.1.2 Description of Cleaning Activities ... 3-3
"^ 3.1.3 Factors that Affect Emissions ..... 3-8
3.2 INDUSTRIES THAT USE VOC SOLVENTS FOR CLEANING . 3-10
3.2.1 Quantitative Overview of Cleaning
Solvents Use .............. 3-10
3.2.2 Accounting/Tracking Procedures ...... 3-14
3.2.3 Cleaning Solvent Use and Emissions in
the Focus Industries .......... 3-17
3.3 REFERENCES FOR CHAPTER 3 ........... 3-27
4.0 SOLVENT ACCOUNTING AND MANAGEMENT SYSTEMS ..... 4-1
4.1 SOLVENT ACCOUNTING SYSTEM ........... 4-4
4.2 SOLVENT MANAGEMENT .............. 4-6
4.2.1 Testing of Alternative Solvents .... 4-7
4.2.2 Plant Management Actions ........ 4-9
4.2.3 State Agency Actions .......... 4-10
4.3 REFERENCES FOR CHAPTER 4 ........... 4-12
5.0 COSTS OF INSTITUTING ACCOUNTING AND MANAGEMENT . . 5-1
5.1 PLANTWIDE CASE STUDY COSTS ..... ..... 5-1
5.1.1 Qualitative Cost Information ...... 5-2
5.1.2 Solvent Accounting Costs ........ 5-5
5.1.3 Cost of Pollution Reduction Techniques . 5-7
5.2 REFERENCES FOR CHAPTER 5 ........... 5-9
APPENDIX A. TERMS AND DEFINITIONS FOR SOLVENT CLEANING . A-l
APPENDIX B. REVIEW AND SUMMARY OF STATE AND LOCAL
CLEANING REGULATIONS ..... ....... B-l
APPENDIX C. UNIT OPERATION APPROACH ......... . C-l
APPENDIX D. AMERICAN AUTOMOBILE MANUFACTURERS
ASSOCIATION (AAMA) PROPOSAL ........ D-l
APPENDIX E. CASE STUDIES ........... ..... E-l
APPENDIX F. DRAFT TEST METHOD FOR DETERMINING THE
PERFORMANCE OF ALTERNATIVE CLEANING FLUIDS . F-l
APPENDIX G. PROCEDURES FOR DETERMINING VOC EMISSIONS
FROM SPRAY GUN CLEANING .......... G-l
APPENDIX H. SPRAY GUN CLEANING PROCEDURES AND MATERIAL
BALANCE CALCULATIONS FOR PAINT SPRAY GUN
UOS AT CASE STUDY PLANT L ......... H-l
iii
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LIST OF FIGURES
Number Page
l-l. Distribution of nationwide emissions in the
focus industries 1-3
3-1. Distribution of nationwide emissions in the
focus industries 3-26
4-1. Controlling cleaning solvent usage 4-2
IV
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LIST OF TABLES
Numbei
1-1
3-1
3-2
3-3
3-4
3-5
3-6
3-7
3-8
3-9
3-10
3-11
4-1
5-1
5-2
^
' EXAMPLE PLANT MANAGEMENT AND STATE
AGENCY ACTIONS
ESTIMATES OF THE AMOUNT OF VOC CLEANING SOLVENT
USED BY INDUSTRY, x 103 tons/yr
ESTIMATES OF THE AMOUNT OF VOC CLEANING SOLVENT
USED BY INDUSTRY, X 1CT Mg/yr
AGENCY DATA GATHERING EFFORT
FREQUENTLY USED INDUSTRIAL CLEANING SOLVENTS . . .
VOLUME OF SALES FOR COMMON CLEANING SOLVENTS . . .
FREQUENCY OF UNIT OPERATION SYSTEM OCCURRENCE . .
UNIT OPERATION SYSTEMS REPORTED BY THE FOCUS
INDUSTRIES
NATIONWIDE VOC SOLVENT USAGE ESTIMATES FOR
FOCUS INDUSTRIES, (tons/yr)
NATIONWIDE VOC SOLVENT USAGE ESTIMATES FOR
FOCUS INDUSTRIES, (Mg/yr)
NATIONWIDE VOC EMISSION ESTIMATE FOR FOCUS
INDUSTRIES, (tons/yr)
NATIONWIDE VOC EMISSION ESTIMATE FOR FOCUS
INDUSTRIES, Mg/yr)
EXAMPLE PLANT MANAGEMENT AND STATE AGENCY
ACTIONS
SUMMARY OF SOLVENT ACCOUNTING COSTS
SUMMARY OF POLLUTION REDUCTION TECHNIQUE COSTS . .
Page
1-6
3-11
3-12
3-13
3-15
3-16
3-19
3-20
3-22
3-23
3-24
3-25
4-8
5-3
5-4
V
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1.0 EXECUTIVE SUMMARY
Congress, in the Clean Air Act Amendments of 1990 (CAAA) ,
supplemented previous mandates regarding control of ozone in
nonattainment areas. A new Subpart 2 was added to Part D of
Title I. Section 183 (c) of the new Subpart 2 provides that:
...the Administrator shall issue technical documents which
identify alternative controls for all categories of
stationary sources of volatile organic compounds ... which
emit, or have the potential to emit 25 tons per year or more
of such air pollutant.
This report provides, alternative control techniques (ACT) for
State and local agencies to consider for incorporating in rules
to limit emission of volatile organic compounds (VOC's) that
otherwise result from industrial cleaning with organic solvents.
A variety of cleaning solvents are used by industry to
remove contaminants such as adhesives, inks, paint, dirt, soil,
oil, and grease. Parts, products, tools, machinery, equipment,
vessels, floors, walls, and other work areas are cleared for a
variety of reasons including housekeeping, safety, operability,
and to avoid product contamination. Solvents are used in
enormous volumes and a portion of evaporates during use, making
cleaning fluids a major source of emissions of VOC. Data
collected by EPA show nationwide usage of VOC solvent from only
six industries is about 380,000 megagrams per year (Mg/yr)
(410,000 tons per year [tons/yr]). Less comprehensive data from
other sources suggest total VOC solvent usage for cleaning by all
U.S. industry is more than 1 million tons each year.
1-1
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On average, 25 percent or more of the solvent that was used
for cleaning purposes by the six industries (automotive,
electrical equipment, metal furniture, photographic supplies,
packaging, and magnetic tape) used for the study was lost by
spillage or evaporation. This value varied significantly among
industries depending on the type of cleaning performed.
The study of the six industries initially tried to
quantitatively evaluate sources of evaporative emissions of VOC
from solvents used as cleaning agents. The plan was to 1)
examine cleaning "activities" such as wiping, spraying, and
dipping to identify the most efficient options and 2) quantify
the potential emission reductions and associated costs if use of
the more efficient were widely mandated. This approach was not
successful because data to support the necessary level of detail
simply was not available. As a result, the Agency was unable to
identify baseline emission levels, emission reductions or costs
associated with this approach.
Subsequently, information was requested from industry using
a different strategy. This time, respondents were asked to
provide usage and waste information for objects or processes that
had been cleaned rather than on the cleaning "activity". Nearly
300 sets of data sets based on this new approach were collected
from the six industries. The responses were closely studied;
numerous calls were made to maximize understanding of the
information.
The data indicated that all use of solvent for cleaning can
be evaluated on the basis of one of only nine general types:
cleaning of spray guns, spray booths, equipment, large
manufactured components, small manufactured components, floors,
tanks, lines and parts. Within each group, however, there is
considerable variation, including differences in cleaning
techniques, soils removed, solvency, and a likely host of others.
Figure 1-1 displays the relative emissions from the nine
types of unit operation systems. Somewhat surprisingly, cleaning
of spray guns accounted for 50 percent of the total emissions
1-2
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UJ
Line Cleaning (3.6%)
Tank Cleaning (0.82%)
Spray Gun Cleaning <50%)
Parts Cleaning (7.0%)
Spray Booth Cleaning (14%}
Sm. Mfg. Components (0.44%)
ROOT Cleaning (2.9%)
Equipment Cleaning (6.9%)
ttw&S:*:1*- l/g. Mfg. Components (14%)
Figure 1-1. Distribution of nationwide emissions in the focus industries
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while most of the remaining were from wiping and spraying the
exterior of various parts and equipment. Cleaning tanks and
small manufactured components accounted for the least emissions.
Equipment cleaning, the most common unit operation, produced only
7 percent of the total emissions.
Although this "unit operation system" approach generated
more comprehensible information, the data were still of
questionable accuracy for several reasons:
1. Most companies maintained only two types of records;
solvents purchased and (as a result of hazardous waste rules)
total contaminated solvent released for disposal as hazardous
waste.
2. Of the total solvent purchased, only part is used for
cleaning purposes; there was little or no information available
to quantify how much.
3. Respondees attempted to estimate the desired
information, but clearly the requisite details were not
available. ^
4. Further, close review of the data that was submitted
revealed that many of the numbers did not balance. The reason
was that in many cases the usage estimates were based either on
solvent inventories or "guesstimates." Also most plants did not
segregate their waste solvent or inadvertently overestimated the
solvent in the waste stream by not subtracting the amount of
contaminants.
5. There was a large variety in the quantities and ways
solvents are used for cleaning, both among and within industries.
6. Communications were difficult and imprecise; all
companies did not closely follow the instructions (and
vocabulary) that accompanied the questionnaire.
Many industrial facilities' solvent costs, at present, are
carried as a plantwide expense item with essentially no records
of where or how the materials are used. For example, for
accounting purposes, solvents are frequently charged as a plant
inventory item (rather than charged against different business
1-4
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centers within the plant). Further, access is often as simple as
opening a valve. No accountability is required. Even at plants
where the cost of cleaning solvents is charged to various
business or cost centers within the plant, usually it is not on a
relative usage basis. Instead, the total solvent cost may be
assigned to the individual cost centers using some surrogate such
as cash flow or number of employees.
Despite the difficulties listed above and general lack of
detailed information on cleaning solvent use, the study revealed
that a number of companies, for a variety of reasons, had found
it in their best interests to reduce the amount of solvent used
for cleaning. The reasons varied, cost of disposal of hazardous
waste, the cost of solvent, employee exposure and state air
pollution rules were factors. Often, a common factor was that
management expressed interest and set priorities on learning
where and how solvents and other chemicals were consumed.
Management concern usually resulted in reduced usage.
Simultaneously, reduced usage resulted in lower emissions and
costs and also moderated the rate and cost of waste generation.
A key element then, to reducing emissions from use of
cleaning solvents is to learn where and how solvents are used.
As demonstrated by some plants in the study, this can be done by
institution of a solvent accounting system that quantitatively
records where cleaning solvent is used. The general consensus of
plants that implemented a solvent accounting system is that the
resulting benefits and cost savings from changes in cleaning
practices or equipment outweigh the costs to implement and
maintain the accounting system.
As an alternative to the initial plan to describe specific
emission control techniques, this document describes a program
that is based on the above findings. The program consists of two
main elements; solvent accounting and plant management (or State
agency) actions. "Accounting" consists of records of the usage,
fate, and cost of cleaning solvents in each business center.
While accounting, in and of itself, may not result in reductions,
1-5
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it will identify and allow attention to be placed on the largest
uses of solvent and sources of emissions.
Once data are available via the solvent accounting system,
plant management and State agencies have a number of options for
reducing solvent usage and emissions. The plant management will
likely focus on actions that affect usage rates, while the State
agencies will emphasize ways to reduce emissions. Example
actions are listed in Table 1-1. One widely applicable action is
to search for alternative cleaning materials that would release
less VOC's to the atmosphere. Avenues for success include use of
either aqueous cleaning fluids or organic cleaning solvents that
evaporate more slowly.
Plants with many cleaning activities, or with many unit
operations, in each cost center may find the cost center level is
too large to allow identification of the major emission sources
in order to initiate steps to reduce solvent emissions. In that
case, data must be assembled on a more focused basis. A
particularly helpful concept is to collect data on a "unit
operation system" (UOS) basis1. A UOS is defined in this study
as an ensemble around which a material balance for cleaning can
be performed. Such a material balance aids detailed quantitative
evaluations of usage and emissions of solvent. The boundaries of
a UOS should be selected to include all possible points/sources
leading to evaporative emission losses associated with cleaning a
specific unit operation, including losses during dispensing the
solvent, spilling virgin and used solvent, handling residual
solvent in cleaning applicators, etc. The UOS approach is
described in Appendix C.
Detailed accounting of data on the input and output streams
for a UOS should result in the best chance to identify areas with
the greatest emission, usage, or waste reduction potential. The
more specific and better defined the UOS, the better the analysis
will be. Implementing the UOS approach or taking other actions
like those on Table 1-1 will ultimately lead to implementation of
emission reduction techniques.
1-6
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TABLE 1-1. EXAMPLES OF SOLVENT MANAGEMENT ACTIONS
Plant management actions
State agency actions
1. Collect data on a UOS
basis in cost centers
where high costs have
been identified.
Require plants to
consider accounting on
a UOS level if cost
center data cannot be
compared among plants.
Compare usage between
two like cost centers
or UOS's and require
action by larger user.
Require plants to
submit individual
solvent reduction
plans.
Provide incentives and
goals to similar cost
centers.
Compare solvent usage
from like UOS's within
a given industry and
require justification
from higher users.
Evaluate potential
alternative cleaning
solutions.
Mandate implementation
of specific solvent
management techniques.
Conduct experiments to
determine minimum
amount needed for each
cleaning task.
Require plants to
conduct extensive,
short-term studies and
to commit to take
action based on
results.
Implement an employee
suggestion program.
Compile and share
information on the use
of cleaning solutions.
Mandate use where
appropriate.
7. Form a task force with
other plant managers to
compare cleaning
practices.
Compile and share
results of alternative
cleaning solution
tests. Mandate use
where appropriate.
1-7
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In short, the first step in reducing emissions from use of
cleaning solvents is to identify those locations within the plant
boundaries where the cleaning solvents are used--and lost--in the
greatest quantity. This can be accomplished by requiring
companies to institute accounting procedures to track the use and
emissions from different places within the plant that use
cleaning solvents.
The second step is to use the knowledge obtained from the
accounting system. Specific actions may be initiated by plant
management or specified by the State Agency. The accounting
system provides a quantitative measure of the results of
corrective actions and helps guard against subsequent regression
to former working conditions.
The automobile industry has suggested an alternative
approach (Appendix D), use of short term intensive studies to
identify methods for reducing emissions from solvent use. This
would obviously be a positive activity, worthy of encouragement
by the State, and perhaps equally effective over the near term.
Some subsequent tracking steps would appear necessary to assure
that the initial success is not subsequently lost.
1. Memorandum from Wyatt.S ., EPA, to project file. February
24, 1994. "Unit Operation System" - Originator of Concept.
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2.0 INTRODUCTION
Congress, in the Clean Air Act Amendments of 1990 (CAAA),
supplemented previous mandates regarding .control of ozone in
nonattainment areas. A new Subpart 2 was added to Part D of
Title I. Section 183 (c) of the new Subpart 2 provides that:
...the Administrator shall issue technical
documents which identify alternative controls
for all categories of stationary sources of
volatile organic compounds ... which emit, or
have the potential to emit 25 tons per year
or more of such air pollutant.
The Act further directs that these documents are to be
subsequently revised and updated at intervals determined by the
Administrator.
This is an alternative control techniques (ACT) document
that discusses industrial cleaning solvents and provides
technical information for State and local agencies to reduce
VOC emissions. Detailed information was collected from surveys
of 6 different U.S. industries, hereafter referred to
collectively as "focus industries," and more general information
from a variety of other sources. Data collected by EPA's surveys
show nationwide usage from the six focus industries is about
380,000 megagrams per year (Mg/yr) (410,000 tons per year
[tons/yr]). Less comprehensive data from other sources suggest
total solvent usage for cleaning by all U.S. industry is more
than 1 million tons each year.
The remainder of this report consists of three chapters and
several appendices. Chapter 3 presents estimates of nationwide
solvent usage and emissions. It also includes discussions of the
2-1
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types of cleaning activities and the contaminants removed during
cleaning.
Chapter 4 presents approaches to prevent cleaning solvent
emissions through better solvent accounting and management
activities. Alternative actions that States and plants can take
to effect reductions are also discussed in Chapter 4.
Chapter 5 presents incremental costs for the accounting
procedures and reduction techniques adopted by those plants that
served as case studies. It also presents the estimated cost
impact (as reported by one plant) of switching the method of
cleaning paint spray guns from manual cleaning procedures to a
machine designed for cleaning such equipment (a gun washer).
The appendices present definitions of terms, a summary of
State and local regulations, a method for estimating fugitive
emissions, a different alternative for achieving reductions in
solvent usage, solvent accounting case studies, a method for
evaluating alternative cleaning fluids, a method for determining
emissions from spray gun cleaning, and a spray gun cleaning case
study.
2-2
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3.0 INDUSTRIAL CLEANING WITH ORGANIC SOLVENTS
A variety of organic solvents are used in enormous volumes
as cleaning fluids by industry. A portion of all solvents
evaporate during use, making cleaning fluids a major source of
emissions of volatile organic compounds (VOC's). This report
describes alternative techniques that will reduce VOC emissions
from those industrial cleaning solvents used to remove
contaminants such as adhesive3, inks, paint, dirt, soil, oil, and
grease. (Vapor degreasers and conveyorized, batch-loaded, and
remote reservoir cold cleaners, when used for cleaning metal
parts, were not addressed in this study, but are addressed in
another report titled "Control of Volatile Organic Emissions
from Solvent Metal Cleaning," EPA-450/2-77-022, November 1977.)
Contaminants must be periodically removed from parts, products,
tools, machinery, equipment, vessels, floors, walls, and other
work areas for a variety of reasons including safety,
operability, and to avoid product contamination.
This chapter, the product of an extensive study of cleaning
activities in a wide and diverse assortment of industrial
facilities, presents an overview of how organic solvents are used
by industry for cleaning. It discusses the industries that use
cleaning solvents, the kinds of solvents used, the type of
cleaning activities performed, and current practices, or lack
there of, for managing the use of solvents.
Further, the chapter describes the material balance concept
used for soliciting information and quantifying emissions. It
also describes the nine categories of "unit operation systems"
(UOS's) into which all types of industrial cleaning were grouped.
3-1
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3.1 OVERVIEW OF CLEANING
This section presents an overview of the cleaning process.
First, four mechanisms by which contaminants are removed are
described. Also presented are discussions of cleaning
"activities" (i.e., dipping, flushing, purging, spraying, and
wiping) and factors, including the degree of cleanliness
demanded, that affect emissions.
3.1.1 Cleaning Mechanisms
The cleaning activities that use organic solvents to remove
contaminants used by industry rely on one or more of the
following four mechanisms.
3.1.1.1 Solubilization. The contaminant must dissolve in
the cleaning solvent which may be either a neat solvent or
solvent mixture.
3.1.1.2 Surface Action. The (nonmechanical) displacement
of the contaminant from the surface that is cleaned through
changes in surface tension. Surface action can be achieved by a
detergent or through emulsification of the contaminant.
For example, a detergent displaces a contaminant with its
surface-active agent or surfactant. Because surfactants exhibit
greater affinity to the surface than do the contaminants, the
latter are displaced by surface phenomenon, the lowering of
surface and interfacial tension.
Emulsification refers to the effect of the contaminant and
the cleaning medium on each other. In the presence of an
emulsifier, portions of the contaminant (e.g., oil) are coated
with a thin film of the cleaning solvent, which prevents
rebonding of the contaminant to itself or to the surface. The
coated contaminant particles remain suspended in the cleaning
medium.
3.1.1.3 Mechanical Auction. The contaminant is physically
displaced by mechanical agitation (e.g., brushing). Solvents are
used to increase the efficiency of the mechanical action via
solubilization or surface action.
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3.1.1.4 Chemical Reaction. A material is added that reacts
with the contaminant to form a soluble product, allowing the
contaminant to be flushed away.
3.1.2 Description of Cleaning Activities
This section discusses dipping, flushing, purging, spraying,
and wiping actions that have been deemed "cleaning activities."
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The second major source is "dragout": evaporation of the
cleaning solvent carried out of the container in recesses or the
interior of the objects being cleaned.
The third source of emissions is associated with the
handling of the spent solvent. If kept in an uncovered vessel,
significant evaporation may take place. Even if the cover is
well gasketed, some evaporative emissions may occur.
3.1.2.2 Flushing. Flushing involves pumping solvent from a
reservoir through a pipe or hose onto or through equipment (e.g.,
pipes, hoses, tanks) to remove contaminants or residue.
During flushing, the solvent is moved through the object
being cleaned. Flushing is frequently used for maintenance
cleaning of the interior of objects or in conjunction with other
manufacturing processes. Reservoirs or piping may be cleaned
prior to storage of new materials (e.g., tank flushing). Process
vessels (e.g., reactors) may be flushed between batches.
In general, flushing requires solvent, a storage tank, a
hose, piping, and a spent solvent container. To flush an object,
portable equipment may be used. The solvent is pumped from its
reservoir through a hose onto or through the object being
cleaned. In some cases, the solvent may be used on a
once-through basis, discharged directly into a container (e.g., a
waste solvent drum), and reused elsewhere in the plant, recycled,
or disposed of as hazardous waste (We presume that operations no
longer intentionally allow spent solvent to evaporate in order to
reduce hazardous waste disposal costs.) In other cases, the
solvent may circulate back to the feed reservoir for reuse the
next time cleaning is required.
Once the solvent becomes so contaminated that it no longer
performs satisfactorily, the entire contents of the reservoir may
be transferred to another container to await recycling within the
plant or disposal as hazardous waste. More elaborate (and
usually fixed) systems are designed to flush large equipment
(e.g., a reactor vessel) at the end of a batch or for periodic
maintenance. In this case, the solvent may be delivered through
built-in piping.
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Flushing dissolves or disperses the contaminants in the
solvent. A contributing factor is agitation, which results from
the force or pressure exerted by the cleaning solvent stream from
the piping.
Emissions from this cleaning activity are minimal provided
that the system does not leak. However, the quantity of fugitive
emissions and the number of emission points can vary depending on
the object being cleaned and the technique used for flushing.
Depending on their construction, emissions can also be associated
with the storage tanks for virgin and spent solvent if they are
open or loosely lidded and with the process line while being
cleaned.
3.1.2.3 Purging. Purging is similar to flushing, but in
this report it applies only to cleaning the interior of spray
guns and other attached equipment (e.g., hoses, paint cups)
cleaned simultaneously with the spray gun. Spray guns are used
primarily to apply paints, other coatings (e.g., resin or wax),
and oil to manufactured products. Typically, spray guns are
cleaned periodically during operation and at the end of
production shifts to prevent plugging. Paint spray guns must
also be cleaned in preparation for a color change.
Spray guns are purged by a variety of techniques. For
example, siphon-feed paint spray guns with attached paint cups
are cleaned manually by adding solvent to the cup and pulling the
trigger to force solvent through the gun and nozzle.
Pressure-feed guns with variable lengths of hose also may be
cleaned manually. Purge solvent in these cases may be used on a
once-through basis or recirculated. Once-through solvent is
sometimes sprayed directly into the air where it all evaporates;
other plants direct the spent solvent to a collection vessel for
disposal or reuse.
Plants that perform a lot of painting often have robotic
spray systems that can recirculate paint and/or cleaning solvent.
These systems are cleaned automatically by solvent that is
delivered through permanent (and dedicated) fixed piping.
Additional fixed piping attached to the base of the gun also
3-5
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either directs most of the used solvent to a spent solvent
storage tank or recirculates it back to the feed tank. Some
robotic or reciprocal equipment have integral recovery systems
that preclude the release of any liquid solvent into the air.
Others permit only the briefest burst of solvent through the gun
tube and nozzle.into the air; where it evaporates.
The pressure exerted by the solvent pushes the bulk of the
paint or other contaminant through the line and gun in semi plug
flow. Some contaminants are dissolved in the solvent.
In addition to evaporation of some or all of the solvent
discharged into the air, emissions may also occur from virgin and
spent solvent storage vessels and leaks from fittings in the
solvent and paint lines.
3.1.2.4 Spraying. Spraying involves applying cleaning
solvent to a surface through a nozzle so that the solvent's
energy of momentum is converted to mechanical pressure as it
impacts the part to be cleaned. It can be used for cleaning
outer or inner surfaces of objects (e.g., the inside or outside
of a tank).
Spraying parts with cleaning solvent saves labor, time, and
money compared to other cleaning activities such as wiping.
Spraying can quickly wet many parts with solvent. Wiping
requires that a worker wet each surface one at a time. Thus the
labor costs of spraying can be several times lower than the costs
of other cleaning activities. However, the equipment costs for
spraying are somewhat higher.
Spray cleaning systems can be either automated or manual.
Automated systems are typically fixed in one location (e.g., a
spray booth), while manual systems can either be fixed or
portable. Automated systems tend to be larger and more complex.
They may include a solvent reservoir to hold virgin solvent,
piping, a pump, spray arms, nozzles, a basket to hold the parts
(for a cold cleaner), and a container to collect spent solvent.
Manually activated spray systems consist of a fixed or portable
reservoir of virgin solvent connected to a pump system and then
3-6
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to a hose and nozzle. Portable solvent reservoirs hold several
gallons of solvent, while fixed storage tanks are much larger.
Solubilization is the primary mechanism for contaminant
removal in spray cleaning. It occurs when an object
(e.g., process equipment) is completely wetted by solvent that
dissolves the contaminant. The impact of pressurized solvent
(i.e., a mechanical action) can also dislodge contaminants,
although only those that adhere loosely to the surface to be
cleaned.
Emission points from spraying activities include (1) the
surface of the object being cleaned (e.g., paint spray booth
walls), (2) the virgin and spent solvent vessels if they are open
or loosely lidded, and (3) the spray equipment itself. The
emissions from the object being cleaned account for a varying
portion of the total emissions. For example, evaporative
emissions from wetting a small part are small compared to those
from cleaning a large object such as the walls of a spray booth.
Factors affecting the relative importance of these emission
points are the vapor pressure of the solvent, the period of time
the solvent is exposed to the air, and the ambient temperature.
3.1.2.5 Wiping. Wiping is a simple form of solvent
cleaning and relies on the solubility of the contaminant in the
solvent or the surface action of the solvent plus the mechanical
loosening of the contaminant from the substrate by rubbing. The
absorbent wiper (e.g., rag, mop, or sponge) absorbs the solvent
and transfers it to the substrate surface. Contaminant particles
dissolve in the solvent, are loosened by surface action, or are
dislodged by applied pressure. Dissolved contaminants are
absorbed by the rag, while the loosened and dislodged particles
either adhere to the rag or are pushed off of the object being
cleaned. Wiping steps are repeated until the object is
sufficiently clean. If the dirty rag, mop, or sponge is rinsed
in the virgin solvent reservoir or the reclaimed solvent
container, some of the contaminant will be transferred to the
solvent in the reservoir. If not, the contaminant generally
remains on the rag.
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Wiping is perhaps the most common cleaning activity:
(1) the contaminant often is more quickly removed because of the
associated mechanical energy used and (2) it is a mobile activity
easily performed anywhere in the plant. Little equipment is
needed. The only costs accrued are for labor and materials;
there is no capital cost. This cleaning activity is most
appropriate for maintenance (e.g., cleaning [machinery, floors,
etc.] in place without disassembly or cleaning large pieces
produced in small quantities that would be impractical to clean
by alternative methods).
The major sources of emissions from wiping activities are
evaporation from vessels that contain fresh and spent solvent,
the solvent-soaked rags or other tools used, and spillage from
containers. Evaporation of residual solvent from cleaned parts
also contributes to emissions.
3.1.3 Factors that Affect Emissions
During cleaning, several factors contribute to the emissions
of solvent. These can be divided into two categories: (1) those
associated with the cleaning practice, and (2) those related to
the physical or chemical properties of the solvent.
Higher evaporative emissions may result from careless or
improper handling of cleaning tools (e.g., rags, brushes) or the
part during and after cleaning. Another practice that increases
solvent emissions is splashing and spillage during handling.
Factors that increase emissions associated with the cleaning
method itself include drying the tools or cleaned parts in areas
ventilated directly to the atmosphere, not using covers (or using
ineffective covers) for both the fresh and waste cleaning
solvent, and using adsorbent or porous items (e.g., ropes, bags)
for handling the solvent-wetted items.
The second category of factors that contribute to
evaporative losses relates to chemical and physical properties of
the solvents. Chemical factors include solvent volatility,
viscosity, and any change in chemical properties caused by
introducing the contaminant into the solvent, such as an increase
or decrease in boiling point, surface tension, etc. Physical
3-8
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factors are mainly associated with the air movement in the
cleaning area and the ambient and process temperatures, all of
which can contribute to increases in evaporation rates.
Still another physical factor is the degree of cleanliness
demanded, that is, the specification for contaminant removal that
must be met. There is no common standard of measurement, and
"clean" varies depending on the application and the industry.
Three general categories of cleanliness are:
1. Cleaning as a step in the manufacture of products.
The primary reason for this type of cleaning is to prepare an
object for a subsequent manufacturing step, such as painting. As
a result, complete removal of the residual cleaning materials or
solvents is typically required. An example is cleaning the
surfaces of a newly manufactured part (e.g., metal furniture)
prior to painting or initiating another coating operation, where
a high standard of cleanliness is necessary to ensure proper
adhesion of the coating. Still another example is use of solvent
to remove mold release compounds from molded plastic products
(such as a fiberglass boat prior to painting the hull) or to
remove all miscellaneous contaminants from a primed car body
prior to topcoating.
In selecting the solvent for cleaning products during
manufacture, performance is the critical test. The solvent must
achieve the desired cleaning in a way that permits the product to
be manufactured competitively. The cost of the solvent is
relatively minor compared to the labor and cost of rework should
the coating fail (or some other problem occur) as a result of
insufficient cleaning. In selecting a cleaning material or
considering a change, one must be mindful that residues of
cleaning materials may be unacceptable. The only acceptable
cleaner may be an organic solvent.
2. Cleaning of process equipment. This cleaning is often
done to prevent cross-contamination between different batches of
material prepared using the same equipment. An example is
cleaning paint manufacturing tanks between production of batches
of different colors. Another is purging coating application
3-9
-------
spray guns and associated lines and hoses with solvent prior to a
color change or at the end of the day's operations.
The cleaning requirement for process equipment may be fairly
rigorous to preclude contamination that would spoil the next
batch or next product (e.g., car). The solvent selected for
cleaning is often the same solvent used in the manufacturing
operation to avoid a compatibility problem.
3. Cleaning before maintenance. Parts and equipment may
need cleaning prior to or during maintenance operations. Cost
and convenience are important concerns affecting solvent
selection. The level of cleanliness may be less important.
Cleaning may be conducted for convenience--to remove grease, for
example--rather than to meet more specific requirements. In
other maintenance circumstances, the cleaning requirements may be
very high.
3.2 INDUSTRIES THAT USB VOC SOLVENTS FOR CLEANING
This section presents a quantitative overview of cleaning
solvent use by industry and a discussion of cleaning solvent
accounting/tracking practices.
3.2.1 Quantitative Overview of Cleaning Solvents jJse
Cleaning activities are an inherent and essential step of
any production process. Solvents are used extensively for this
purpose by many industries. Table 3-1 lists 13 industries, known
/
to so use organic solvents and presents estimates of nationwide
use in each industry. (Corresponding metric values are shown in
Table 3-2.) These tables reveal that the total usage for those
industries are somewhere between 270 and 1,400 tons/yr (240 and
1,300 Mg/yr). This is a low estimate of total nationwide use
because many other industries are known to also clean with
organic solvents.
Estimates were obtained from five sources. Four are
previous studies by the Agency that reported the nationwide use
of organic solvents for all purposes by certain industries.1"4
The fifth source is the current study.5 Tables 3-1 and 3-2 are
based on information from the first four and a ratio of cleaning
solvent to total solvent usage developed during the current
3-10
-------
TABLE 3-1. ESTIMATES OF THE AMOUNT OF VOC CLEANING SOLVENT USED
BY INDUSTRY, x 103 tons/yr
Industry
Automotivemanufacturing
(3711)
Automotive-trucks and
buses (3713)
Automotive parts/access.
(3714)
Automotive-stamping (3465)
Adhesives
Packaging
Plastics
Furniture
Rotogravure printing
FRP boats
Autobody refinishing
Electrical equipment
Magnetic tape
Photographic supplies
(chemicals)
Offset lithographic printing
Total
Reference
1
89-410*
73-330
19-88
7.8-35
2
14-62
8.3b
5.5b
3.9b
l.l-6.6b
3
46-210
28-130
16-72
4
26-120
5
72
16
7.7
1.0
30
230
5.6
11
41
Low
72
16
7.7
1.0
46
30
28
19
14
8.3
7.8
5.6
5.5
3.9
1.1
270
High
410
16
7.7
1.0
330
30
130
230
62
8.3
120
5.6
11
41
6.6
1,400
CO
"Tliis range may represent usage in more than the 3711 SIC subcategory.
''Estimate based on a usage = emissions assumption.
-------
TABLE 3-2. ESTIMATES OF THE AMOUNT OF VOC CLEANING SOLVENT USED
BY INDUSTRY, x 103 Mg/yr
Industry
Automotivemanufacturing
(3711)
Automotive trucks and
buses (3713)
Automotive parts/access.
(3714)
Automotive stamping
(3465)
Adhesives
Packaging
nasties
Furniture
Rotogravure printing
FRP boats
Autobody refinishing
Electrical equipment
Magnetic tape
Photographic supplies
(chemicals)
Offset lithographic printing
Total
Reference
1
81-370*
67-300
21-80
7.1-32
2
12-56
7.5b
5.0b
3.5b
1.0-6.0b
3
42-190
25-120
14-66
4
24-110
5
65
15
7.0
0.9
27
210
5.1
10
37
Low
65
15
7.0
0.9
42
27
25
21
12
7.5
7.1
5.1
5.0
3.5
1.0
240
High
370
15
7.0
0.9
300
27
120
210
56
7.5
110
5.1
10
37
6.0
1,300
U)
I
"This range may represent usage in more than the 3711 SIC subcategory.
bEstimate based on a usage = emissions assumption.
-------
study. Table 3-3 summarizes the number of facilities and number
of data sets obtained from the six focus industries in the
current study. Data were gathered through information requests
designed to obtain a variety of information on cleaning
practices, including the type and volume of solvents used.
Cleaning solvent usage and emissions in the six industries are
discussed further in Section 3.2.3.
TABLE 3-3. AGENCY DATA GATHERING EFFORT
Industry
Automotive --Manufacturing (3711)
Automotive --Trucks /buses (3713)
Automotive --Parts/access. (3714)
Automotive --Stamping (3465)
Electrical equipment
Magnetic tape
Furniture
Packaging
Photographic supplies (chemicals)
TOTAL
No. of
facilities
8
1
1 4
2
8
3
6
1
1
34
No. of data
setsa
78
7
18
6
63
14
87
6
14
293
aA data set is all the data gathered that pertained to the
cleaning of one industrial unit operation or several similar
unit operations, depending on how each facility reported
data.
Cleaning solvent usage makes up 9 to 41 percent of total
solvent usage, based on data from seven of the plants surveyed
for this study.6 They were the only plants (four in the
electrical equipment, and one each in the furniture, packaging,
and photographic supplies industries) that provided sufficient
data to calculate the ratio. This 4-fold range was used to
calculate nationwide usage values for References l through 4 in
Tables 3-1 and 3-2.
3-13
-------
The 4-fold range was also used to estimate a lower bound of
national cleaning solvent usage in all industry. These resulting
values are believed low because they are based on sales of only
19 solvents; others may also be used as cleaners. Table 3-4 lists
frequently used cleaning solvents at the plants in the focus
industries. Only solvents used at three or more plants (as
either a single compound or as a component of a mixture) are
included in the table.7 Total annual U.S. sales of these same
solvents are compiled in Table 3-5.8 Applying the
cleaning-to-total solvent usage ratio to these sales resulted in
an estimated national cleaning solvent usage of 1.3 to
5.7 million tons/yr (1.2 to 5.3 million Mg/yr).
Data from nine automotive assembly plants reveal cleaning
solvent emissions ranging from 22 to 61 percent of the total
emissions.^ (However, one furniture manufacturer reported
cleaning emissions to be only 1 percent of the total.) Although
the usage (9 to 41 percent) and emission (22 to 61 percent)
ratios were based on data from plants in separate industries,
conclusions can be drawn from the differences. The differences
suggest that a plant cannot use a known usage ratio as an
accurate approximation of an unknown emissions ratio. This
result is to be expected, considering emissions from production
uses of solvent are independent of emissions from cleaning uses.
For example, a portion of cleaning solvent may be collected and
reclaimed, while all production solvent may be used as a paint
thinner and ultimately emitted either during manufacturing or
later use of the paint.
3.2.2 Accounting/Tracking Procedures
The EPA's study also revealed that many industrial
facilities carry the cost of solvents as a plantwide expense item
with essentially no records of where or how the materials are
used. For example, for accounting purposes, solvents are
frequently charged as a plant inventory item (rather than charged
against different profit centers within the plant). Further,
access is often as simple as opening a valve. No accountability
is required. Even at plants where the cost of cleaning solvents
3-14
-------
TABLE 3-4. FREQUENTLY USED INDUSTRIAL CLEANING SOLVENTS7
Solvent name
Acetone
Alcoholsb
Butyl acetate
Cyclohexanone
Ethanol
Ethyl acetate
Ethyl benzene
Ethylene glycol
Isopropyl alcohol
Methanol
Methyl ethyl ketone
Methyl isobutyl ketone
Naphthad
Perchloroethyleoe
Toluene
Xylene
Hazardous air
pollutant*
No
c
No
No
No
No
Yes
Yes
No
Yes
Yes
Yes
e
Yes
Yes
Yes
Solvent occurrences
As pure
solvent
5
2
1
4
13
6
-
9
16
1
10
6
12
As part of
compound
formulation
8
1
5
--
5
4
6
3
8
6
4
9
13
3
11
19
Solvent
concentration in
compound
formulation, %
11-57
12-38
-
49-95
2-50
1-20
5-10
9-35
3-20
3-75
2-50
6-98
1-36
1-51
1-83
aSee Appendix A for the definition of a hazardous air pollutant (HAP). Those compounds that are HAP's
are subject to regulation under Section 112 of the Clean Air Act.
"Total nonspecified production of Cjj or lower unmixed alcohols.
Unknown whether this class includes HAP's.
''This solvent includes naphthas, petroleum naphtha, VM&P naphtha, mineral spirits, stodard solvents,
naphthols, and naphthanols.
''Naphthas may include HAP's.
3-15
-------
TABLE 3-5. VOLUME OF SALES FOR COMMON CLEANING SOLVENTS
8
Solvent name
Acetone
Alcohol sa
Butyl acetate
Cy c 1 ohexanone
Ethanol
Ethyl acetate
Ethyl benzene
Ethylene glycol
Isopropyl alcohol
Methanol
Methyl ethyl
ketone
Methyl isobutyl
ketone
Naphtha
Perchloroethylene
Toluene
Xylene
TOTAL
Total U.S. sales
for 1990, Mg/yr
760,000
4,100,000
930,000
51,000
280,000
110,000
470,000
230,000
560,00.0
2,400,000
240,000
49,000
b
170,000
1,600,000
1,300,000
13,000,000
Total U.S. sales
for 1990, tons/yr
840,000
4,500,000
100,000
57,000
330,000
130,000
510,000
250,000
620,000
2,600,000
260,000
54,000
b
180,000
1,700,000
1,500,000
14,000,000
aTotal nonspecified
alcohols.
bFigure unavailable.
production of
or lower unmixed
3-16
-------
is charged to various business or coat centers within the plant,
usually it is not on a relative usage basis. Instead, the total
solvent cost may be assigned to the individual cost centers using
some surrogate such as cash flow or number of employees.
Only one response indicated that the amount of solvent used
for cleaning is actually measured, and then only for the solvent
added or removed from a parts washing dip tank. Most facilities
responded that they record only the total amount of solvent
purchased and disposed. The amount purchased is available from
purchase orders, and disposal information is maintained in
Resource Conservation and Recovery Act manifests, biannual
reports, and Treatment, Storage, and Disposal Facilities disposal
records. Regulatory .requirements were cited as the primary
reason for existing recordkeeping practices. In some larger
facilities, some form of recordkeeping is mandated by corporate
requirements.
Part of the reason for such imprecise accounting is
historical, but another is the cost associated with a more
quantitative tracking system. In many automobile manufacturing
plants, for example, a solvent line (pipe) makes solvent
available to every painter or cleaning employee in a spray
booth.9 At the turn of a valve, the employee has access to an
unlimited supply of solvent. To quantify the usage by booth,
employee, or other plant segment would require an investment in
both meters and labor to enter the results into a plant
accounting system.
3.2.3 Cleaning Solvent Use and Emissions in the Focus Industries
Cleaning with solvents in an industrial setting may be
perceived on a unit-operation (UO) basis. The conventional unit
operation, a term common to the chemical engineering discipline,
is an industrial operation classified or grouped according to its
function in an operating environment. Unit operations vary
considerably among industries.
Data were solicited during this study from the six focus
industries based on a material balance around a unit operation
system (UOS) . The concept of the unit operation "system" extends
3-17
-------
the boundaries of the conventional "unit operation." The UOS is
defined as the ensemble around which a material balance for
cleaning can be performed. The boundaries of a UOS should be
selected to include all possible points/sources leading to
evaporative emission losses associated with cleaning a specific
unit operation, including losses during dispensing the solvent,
spilling virgin and used solvent, handling residual solvent in
cleaning applicators, etc.
Nine types of UOS's were identified in this study that are
believed to be representative of most solvent cleaning performed
by all industry. These are: spray gun cleaning, spray booth
cleaning, large manufactured parts cleaning, equipment cleaning,
floor cleaning, line cleaning, parts cleaning, tank cleaning, and
small manufactured parts cleaning. A detailed explanation of UOS
can be found in Appendix C.
3.2.3.1 Distribution of UOS's at Surveyed Plants.
Table 3-6 presents the relative numbers of each UOS received in
response to the Agency's information request. Data on a total of
293 UOS's were provided by industry. The equipment cleaning UOS
was the most common, 28 percent, and parts cleaning was second at
23 percent. Only one industry, automotive, reported all nine
types of UOS. The automotive industry submitted 38 percent of
the total entries, while three, automotive, electrical equipment,
and furniture, submitted 90 percent of the total.10
Equipment and parts cleaning were performed by all focus
industries. Large manufactured components cleaning (i.e., the
cleaning of large components during manufacture) and line
cleaning each appear in only two (large manufactured components
cleaning was reported by the automotive and furniture industries,
while line cleaning was reported by the automotive and magnetic
tape industries). Spray booth cleaning was reported only by the
automotive industry. Table 3-7 details the types of UOS's
reported by each focus industry.
3-18
-------
TABLE 3-6. FREQUENCY OF UNIT OPERATION SYSTEM OCCURRENCE
Focus industry
Automotive-
manufacturing (3711)
Automotive-
trucks/buses (3713)
Automotive-
parts/access. (3714)
Automotive-
stamping (3465)
Electrical equipment
Furniture
Magnetic tape
Packaging
Photographic supplies
(chemicals)
Total
Distribution of unit operation systems, percent
Equipment
cleaning
2.4
-
.68
-
7.5
12
1.4
1.0
3.1
28
Floor
cleaning
1.4
-
-
-
1.7
0.34
0.34
3.8
Large
manufactured
components
cleaning
7.9
1.4
-
-
2.7
~
-
12
Line
cleaning
2.4
-
--
-
0.34
-
2.7
Parts
cleaning
0.34
-
3.8
1.7
6.1
8.5
1.4
.68
0.34
23
Small
manufactured
components
cleaning
1.4
-
-
0.34
4.4
4.4
-
-
11
Spray
booth
cleaning
3.8
-
. _
~
-
3.8
Spray gun
cleaning
5.1
1.0
1.7
-
1.7
2.4
-
-
0.34
12
Tank
cleaning
2.1
-
-
--
-
1.7
~
.68
4.4
Total
27
2.4
6.1
2.1
22
30
4.8
2.1
4.8
100
OJ
I
H
vo
-------
TABLE 3-7.
UNIT OPERATION SYSTEMS REPORTED BY THE FOCUS
INDUSTRIES
Industry
Automotive -
manufacturing (3711)
Automotive -
Trucks/buses (3713)
Automotive -
Parts/access. (3714)
Automotive -
Stamping (3465)
Electrical components
Furniture
Magnetic tape
Packaging
Photographic supplies
(chemicals)
Unit operation system
Equipment cleaning
Floor cleaning
Large manufactured components
Line cleaning
Small manufactured components
Spray booth cleaning
Spray gun cleaning
Tank cleaning
Large manufactured components
Spray gun cleaning
Equipment cleaning
Parts cleaning
Spray gun cleaning
Parts cleaning
Small manufactured components
Equipment cleaning
Floor cleaning
Parts cleaning
Small manufactured components
Spray gun cleaning
Equipment cleaning
Large manufactured components
Parts cleaning
Small manufactured components
Spray gun cleaning
Equipment cleaning
Floor cleaning
Line cleaning
Parts cleaning
Tank cleaning
Equipment cleaning
Floor cleaning
Parts cleaning
Equipment cleaning
Parts cleaning
Spray gun cleaning
Tank cleaning
3-20
-------
3.2.3.2 Usage. Estimates of the nationwide amount of
VOC-based solvents used in the focus industries are shown in
Table 3-8. (Metric values are in Table 3-9.) These estimates
were based on nationwide extrapolation of usage-per-employee
factors for the surveyed plants (using total plant employment).5
Equipment cleaning, the most common UOS, consumes only about
3 percent of the cleaning solvent used in the focus industries.
Spray gun cleaning, which constituted only 12 percent of the
UOS's, consumes more than 50 percent of the solvent used.
3.2.3.3 Emissions. Nationwide emission estimates of VOC's
from the nine UOS in the focus industries are presented in
Table 3-10 (metric values are in Table 3-11.) These estimates,
limited to the focus industries, are useful primarily for
comparing emissions among the variety of systems. They were
developed using the same procedure used to estimate the
nationwide usage estimates. First, emission factors were
developed for each UOS using emissions and plant employment data
from the surveyed plants. These factors were then used with
total employment figures for each industry to estimate the
nationwide emissions.5
The tables indicate that spray gun cleaning is the largest
emission source in the focus industries, while cleaning tanks and
small manufactured components is the smallest. Figure 3-1
displays the relative emissions from the nine types of UOS's.
Although spray gun cleaning constituted only 12 percent of the
entries shown in Table 3-6, it is by far the largest source of
emissions, 50 percent. Equipment cleaning, the most common UOS,
produces only 7 percent of the total. The three highest-emitting
.systems, cleaning of spray guns, spray booths, and large
manufactured components, account for 78 percent of the total
emissions.
Cleaning of internal surfaces (spray guns, lines, tanks, and
spray booths) accounts for nearly 70 percent of the total
emissions. Cleaning of external surfaces (equipment, floor,
large and small manufactured components) accounts for nearly
3-21
-------
TABLE 3-8. NATIONWIDE VOC SOLVENT USAGE ESTIMATES FOR FOCUS INDUSTRIES (TONS/YR)a
Focus industry
Automotive
- Manufacturing
- Trucks/buses
- Parts/access.
- Stamping
Electrical equipment
Furniture
Magnetic tape
Packaging
Photographic
supplies
Totalb
Nationwide VOC solvent usage by unit operation system, tons/yr
Equipment
cleaning
220
15
500
7,300
670
1,300
4,400
14,000
Floor,
cleaning
570
77
5,900
3.1
6,600
Large
manufactured
components
cleaning
8,400
6,900
900
16,200
Line
cleaning
14,000
39,000
330
53,000
Parts
cleaning
129
7,600
1,000
1,900
1,800
2,400
23,000
130
38,000
Small
manufactured
components
cleaning
180
13
290
130
610
Spray
booth
cleaning
17,000
17,000
Spray
gun
cleaning
28,000
8,800
130
2,800
180,000
5.3
220,000
Tank
cleaning
3,100
7,700
36,000
47,000
Totalb
72,000
16,000
7,700
1,000
5,600
230,000
11,000
30,000
41,000
410,000
CJ
to
to
1 ton = 2,000 lbm.
"Estimates based on nationwide extrapolation of usage
"Totals are different due to rounding.
-per-employee factors from surveyed plants (using total plant employment).
-------
TABLE 3-9. NATIONWIDE VOC SOLVENT USAGE ESTIMATES FOR FOCUS INDUSTRIES (MG'/YR)a
Focus industry
Automotive
- Manufacturing
- Tracks/buses
- Parts/access.
- Stamping
Electrical equipment
Furniture
Magnetic tape
Packaging
Photographic supplies
Total
Nationwide VOC solvent usage by unit operation system, Mg/yr
Equipment
cleaning
200
14
450
6,400
600
1,200
4,000
13,000
Floor
cleaning
S20
70
5,400
2.8
5,900
Large
manufactured
components
cleaning
7,600
6,300
810
15,000
Line
cleaning
13,000
36,000
300
49,000
Parts
cleaning
120
6,900
940
1,700
1,500
2,200
21,000
120
34,000
Small
manufactured
components
cleaning
160
12
270
HO
540
Spray
booth
cleaning
16,000
16,000
Spray gun
cleaning
26,000
8,000
120
2,600
170,000
4.8
200,000
Tank
cleaning
2,800
7,000
33,000
43,000
Total .
65,000
14,000
7,000
950
5,100
210,000
10,000
27,000
37,000
380,000
u>
to
u>
1 Mg = 106 g
'Estimates based on nationwide extrapolation of usage-per-employee factors from surveyed plants (using total plant employment).
-------
TABLE 3-10. NATIONWIDE VOC EMISSION ESTIMATE FOR FOCUS INDUSTRIES, tons/yr
Focus industry
Automotive-
manufac luring
(3711)
Automotive-
trucks/buses (3713)
Automotive-
parts/access. (3714)
Automotive-
stamping (3465)
Electrical equipment
Furniture
Magnetic tape
Packaging
Photographic
supplies (chemicals)
Total"
Emissions per unit operation system
Equipment
cleaning
220
15
450
5,600
230
960
110
7,600
Floor
cleaning
570
77
2,500
3.1
3,200
Large
manufactured
component
cleaning
7,700
6,900
840
15,400
Line
cleaning
130
3,800
6.6
3,900
Parts
cleaning
130
2,100
320
520
540
440
3,500
1.3
7,600
Small
manufactured
component
cleaning
180
13
220
72
490
Spray
booth
cleaning
15,000
15,000
Spray
gun
cleaning
9,500
8,800
55
1,100
36,000
5.3
55,000
Tank
cleaning
110
430
360
900
Total*
34,000
16,000
2,200
330
2,400
47,000
1,100
7,000
480
109,000
U)
^
to
1 ton = 2,000
"Totals do not match due to rounding.
m
-------
TABLE 3-11. NATIONWIDE VOC EMISSION ESTIMATE FOR FOCUS INDUSTRIES, Mg/yr
Focus industry
Automotive-
manufacturing (37 1 1}
Automotive-
trucks/buses (3713)
Automotive-
parts/access. (3714)
Automotive-stamping
(3465)
Electrical equipment
Furniture
Magnetic tape
Packaging
Photographic
supplies (chemicals)
Total*
Emissions per unit operation system
Equipment
cleaning
200
14
410
5,100
210
870
100
|_ 6,900
Floor
cleaning
520
70
2,300
3
2,900
Large
manufacturing
components
cleaning
7,000
6,300
760
14,000
Line
cleaning
120
3,400
6
3,500
Parts
cleaning
120
1,900
290
470
490
400
3,200
1
6,900
Small
manufacturing
components
cleaning
160
12
200
65
l_ 440
Spray
booth
cleaning
14,000
14,000
Spray gun
cleaning
8,700
8,000
50
1,000
32,000
5
50,000
Tank
cleaning
95
390
330
820
Total8
30,000
14,000
2,000
300
2,100
42,000
1,000
6,400
440
99,000
UJ
I
to
in
1 Mg = 106 g.
'Totals are not equal due to rounding.
-------
Line Cleaning (3.6%)
Tank Cleaning <0.82%)
Spray Gun Cleaning (50%)
Parts Cleaning (7.0%)
Spray Booth Cleaning (14%}
Sm. Mfg. Components (0.44%)
Floor Cleaning (2.9%)
Equipment Cleaning (6.9%)
:;:;:;£:*>- Lrg. Mfg. Components (14%)
(NOTE: Emission estimates based on data for unit operation systems).
Figure 3-1. Distribution of nationwide emissions in the focus industries.
-------
25 percent of the total emissions. Parts cleaning produces about
7 percent of the total emissions.
The percentage of solvent used that is lost through
evaporation varies among the focus industries depending on the
types of cleaning required. For example, the furniture industry,
with a lot of spray gun cleaning that generates waste solvent,
emitted about 20 percent of all cleaning solvent that it used.
For the automotive assembly industry, which uses wiping
activities as well as spray gun cleaning, the emissions were
almost 50 percent of usage. Most of the other industries fell
within this range.
Emissions are probably underestimated by most companies
because values for the quantities of solvent in wastes are
generally inflated. Many of the surveyed plants did not report
and probably never account for contaminant concentrations in the
waste solvent. Others merely estimated the values in response to
a question of the Agency's survey, in the absence of analysis for
VOC content of the waste. For spray gun cleaning, a similar
underestimation occurs when plants do not account for paint in
spraygun lines that is purged into a spent solvent tank during
spraygun cleaning. This paint contains solvent as thinner, and
plants do not account for this additional solvent.
3.3 REFERENCES FOR CHAPTER 3
l. Radian Corporation. Analysis of Solvent Consumption and
End-Uses for Specific Chemicals. Draft Report. EPA
Contract No. 69-02-4288. September 28, 1990. pp. 6.1-4.
2. Radian Corporation. Preliminary Review of 19 Source
Categories of VOC Emissions. Final Report. EPA Contract
No. 69-02-4378. May 20, 1988. pp. 19.2-6.
3. The Research Corporation of New England. End Uses of
Solvent Containing Volatile Organic Compounds. Final
Report. EPA Contract No. 68-02-4379. May 1979. Part I,
p. 21. \
4. Midwest Research Institute. Reduction of Volatile Organic
Compound Emissions from Automobile Refinishing. CTC Report.
EPA Contract No. 68-02-4379. October 1988. p. 6.
3-27
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5, Memorandum from Schmidtke, K., MRI, to project file.
January 8, 1993. Calculations of Nationwide VOC Cleaning
Solvent Usage and Emissions from Focus Industries.
6. Memorandum from Schmidtke, K., MRI, to project file.
July 2, 1993. Cleaning solvent as a percentage of total
solvent usage and emissions at surveyed plants.
7. Memorandum from March, D., MRI, to project file. April 28,
1993. Summary of common cleaning solvents from the project
data base.
8. U.S. Production and Sales 1990. In: Synthetic Organic
Chemicals. U.S. Industry Trade Commission. Publication
No. 2470. December 1991.
9. Telecon. Berry, J., EPA/CPB, with Mishra, R., General
Motors Corporation. 1992. Program to reduce chemical use
and costs.
1992.
10. Memorandum from March, D., MRI, to project file.
April 28, 1993. Number and frequency of unit operation
system occurrences in data base.
3-28
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4.0 SOLVENT ACCOUNTING AND MANAGEMENT SYSTEMS
Numerous VOC solvents are used for a multitude of industrial
cleaning purposes. They are used to remove a variety of
contaminants from many types of surfaces in all of the different
unit operation systems (UOS's). This heterogeneity makes it
difficult to identify "control techniques" that apply universally
to all examples of one type of UOS (although it may be possible
to develop such control techniques for a specific subcategory
within one type of UOS, as discussed in Appendix K for spray gun
cleaning).
Instead of specific control techniques, this chapter
describes a program that is designed to reduce solvent usage, and
allows plants wide latitude in selecting methods to achieve
reductions. In this analysis, "usage" refers to the amount
actually used in each cleaning activity. Thus, reducing usage
also reduces emissions. Reuse and recycling of dirty solvent are
not cleaning usage reduction techniques. They may reduce both
the amount of solvent purchased and hazardous waste disposal, but
they do not reduce the amount used for a cleaning activity.
Figure 4-1 outlines the program, which consists of two main
elements: solvent accounting and solvent management. The first
step toward reducing usage within a facility is to understand
current solvent use practices, which is accomplished by
establishing a solvent accounting system to track (i.e., measure
and record) the use, fate, and cost of all cleaning solvents in
the plant. The records would be developed at the cost center
level at the plant. Such a tracking system, in and of itself,
does not necessarily reduce solvent usage. It does, however,
identify and allow attention to be focused on the largest points
4-1
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SOLVENT ACCOUNTING
SYSTEM
to
PLANT MANAGEMENT
ATTENTION
KNOWLEDGE OF SOLVENTS
USAGE, FATE, AND COSTS
I
SOLVENT
MANAGEMENT
STATE AGENCY
ATTENTION
POTENTIAL EMISSION REDUCTION TECHNIQUES
--CHANGE SOLVENT
-CHANGE WORK PRACTICES
-MODIFY EQUIPMENT OR PROCESSES
-USE ADD-ON CONTROL DEVICES
Figure 4-1. Controlling cleaning solvent usage,
-------
of usage. It can set the stage for any of several subsequent
activities that can have a profound impact on overall solvent
consumption. Additional details about tracking procedures and
options are presented in Section 4.1.
In the second phase of the program, plant managers and/or
State agencies take action based on knowledge acquired via the
solvent accounting system. Such actions include application of
material balances around individual cleaning activities within
the cost center to determine which have the highest emissions,
evaluation of alternative cleaning solutions, and experimentation
to determine the minimum amount of solvent needed for particular
jobs. Ultimately, the knowledge and actions will result in the
implementation of emission reduction techniques. Collectively,
any combination of these or other actions is referred to as part
of a. "solvent management system." Additional information about
possible plant management and State agency actions is presented
in Section 4.2.
Emission reduction techniques can be grouped into two
categories--those that reduce evaporation at the source (unit
operation) and those that control emissions. Actions that may
reduce emissions at the source include switching to a different
cleaner, reducing usage rates, and increasing collection of used
solvent. Reduced usage and increased collection may be
accomplished by changing work practices, modifying equipment
(e.g., tools used in cleaning, solvent storage vessels, solvent
dispensers), or changing a. process. After the release of
emissions, the only way to reduce emissions is with containment
or capture and use of an add-on air pollution control device.
Many plants that implemented a program similar to this have
reported reduced cleaning solvent usage. Case studies are
highlighted in Appendix E. Similar benefits were noted by
researchers that reviewed the procedures many companies used to
identify cost-effective source reduction programs in areas other
than solvent cleaning. They found that plants with rigorous
accounting procedures for both cost and materials implemented an
average of three times as many pollution reduction techniques as
4-3
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did plants with only rigorous accounting for materials. (All
plants had materials accounting procedures.) Rigorous cost
accounting procedures incorporate pollution costs and charge them
against specific processes (i.e., unit operations) rather than to
general overhead. Plant size was not a factor in a plant's
ability to adopt accounting procedures. Both small and large
plants implemented accounting systems and successfully identified
reduction techniques. Most of the implemented reduction
techniques were cost, effective, about 75 percent with payback
periods of less than l year.1
The researchers also determined that other features of
successful reduction programs include employee involvement and
full managerial participation. Endorsement by both plant and
environmental management has also proven to be integral to the
success of reduction programs. Plants adopting these features
implemented an average of twice as many reduction techniques as
plants that failed to secure employee involvement and full
managerial participation.1 These concepts can also be used to
reduce cleaning solvent usage. For example, operators and
production personnel understand specific cleaning needs well, and
soliciting suggestions from and involving them in reduction
programs can provide a source of valuable information in
identifying possible areas for attention.
4.1 SOLVENT ACCOUNTING
As noted in Section 3.2.2, the Agency's investigation into
the use of solvent for cleaning revealed that for accounting
purposes, solvents traditionally have been considered a plant
"supply" or overhead item. That is, their use is so ubiquitous
within a plant that the cost may be borne as a simple line item
that is paid as overhead or is allocated across an entire plant
or among the various internal cost centers on some artificial
basis. Consequently, only the total amount of each solvent
purchased and the total waste disposal shipments are a matter of
record. This traditional process provides no real measure or
paper trail of the relative usage by different segments of the
plant. It provides no incentive (and perhaps significant
4-4
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disincentives) to the individual cost center managers to conserve
solvents (if everyone is paying, no one feels ownership). At
best, such accounting procedures could lead to wasteful use
because the charges to a specific cost (business) center are
either zero or merely an artificially prorated portion of the
incremental cost of wasted material.
The first step in problem solving is to define the problem.
In the case of solvent usage, the Agency has concluded that
successful "source reduction," or pollution-prevention, programs
for reducing usage are possible only when management has more
knowledge about use, fate, and associated costs (purchase and
disposal) than presently exists in most American industries. The
first step towards acquiring this knowledge is instituting a
tracking program that enables the plant personnel to identify and
quantify these parameters. Management interest should then focus
where large quantities of the solvent are used (and emitted).
An avenue to increasing management awareness is to debit
each cost center within the plant for the actual purchase and
disposal costs associated with its use of solvent. The
accounting systems can most easily be established within existing
cost centers at a plant where other plant charges such as raw
materials and utilities are already cumulated in periodic
reports. There are advantages, however, to narrowing the focus
even further to track data at the cleaning activity level within
the cost centers because it identifies exactly where high solvent
use and thus, cost occurs.
The accounting system generates line entries on the monthly
cost sheet for each cost center that show the actual usage and
waste disposal costs. To generate this information, all solvent
inputs to and outputs from the cost center must be measured and
recorded. Inputs include both virgin cleaning solvent and spent
solvent from other processes that is used for cleaning. Outputs
include the amounts of solvent collected for recycling,
reclamation, and disposal. To be useful, the VOC portion of each
input or output stream must be determined. (VOC emissions would
4-5
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then be calculated as the difference between the usage and the
collection rates.)
Tracking solvent use can be done in a number of ways. . One
is to include cleaning solvents in the plant's material inventory
system. The information to be recorded includes the name of the
solvent, the amount dispensed during the month, and the cost
center in which the solvent is used. Ideally, meters would be
installed in lines that supply large amounts of solvent, as in
the case of spray gun/line cleaning in some major facilities such
as auto assembly plants.
Tracking the fate of collected solvent also can be performed
in a number of ways. An acceptable approach must record the
total amount that is collected from its respective cost center.
To determine the VOC content of spent solvent streams (for use in
the material balance), samples should be analyzed periodically in
order to correct the shipping weight to account for contaminants.
To properly sensitize middle management to the cost
associated with cleaning solvents and improve its ability to
identify and control costs, it is necessary to charge the cost of
the solvents' use, for both purchase and waste disposal, to the
individual cost centers within the plant. This procedure
provides the incentive for and allows managers to use the same
management techniques to control costs associated with cleaning
solvents that they use to control costs for utilities such as
steam or cooling water. Each month when the cost sheets are made
available, the cost center manager can compare the current usage
and costs to historical values. With it, the manager can measure
success in reducing usage. Subsequently, when the cost sheet
shows an increase in usage, it will signal that remedial action
is required.
4.2 SOLVENT MANAGEMENT
Once data are available via the solvent accounting system,
plant management and State agencies have a number of options for
reducing solvent usage and emissions. The plant management will
likely focus on actions that affect usage rates, while the State
4-6
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agencies will emphasize ways to reduce emissions. Example
actions are listed in Table 4-1.
One widely applicable action is to search for alternative
cleaning materials that would release less VOC's to the
atmosphere. This may be accomplished by evaluating the relative
performance of alternative cleaning solutions to those solvents
currently emitted in large amounts. Testing for alternatives is
an essential step in a search for cleaning fluids that are less
volatile and have lower-VOC content and even cleaning solutions
with no VOC's that might replace current solvents. Testing
alternatives and other actions are discussed separately below.
4.2.1 Testing of Alternative Solvents
A screening test of potential alternative cleaners is the
first step. A screening test can identify whether the
alternative cleans as well as, better than, or worse than the
existing solvent. Solvents that pass the screening test should
then be evaluated relative to other criteria (e.g., the effect on
performance of a subsequent coating, the relative level of
scrubbing effort, solvent and disposal costs, the impacts on the
substrate, safety, and recyclability).
ASTM Method D-4828, "Standard Test Method for Practical
Washability of Organic Coatings," would appear adaptable for use
in comparing the cleaning effectiveness of solvents and other
cleaners. It was developed originally to determine the
effectiveness of removal of a variety of organic contaminants
from a painted substrate by manual or mechanical washing with a
sponge and a liquid or powdered cleaner. A modified version of
this method, which allows the company to exercise wide latitude
in selecting both the contaminants and substrates for test, is
presented in Appendix F. The method describes how the
contaminant is to be applied to test panels (i.e., the
substrate), how the solvent or cleaner is to be applied to the
sponge, and the number of wipes to be performed, if appropriate.
As designed, the method requires evaluation of the performance
based on a visual comparison of the degree to which the
contaminants are removed from the test panel. The impact of the
4-7
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TABLE 4-1. EXAMPLES OF SOLVENT MANAGEMENT ACTIONS
Plant management actions
State agency actions
1. Collect data on a UOS
basis in cost centers
where high costs have
been identified.
Require plants to
consider accounting on
a UOS level if cost
center data cannot be
compared among plants.
Compare usage between
two like cost centers
or UOS's and require
action by larger user.
Require plants to
submit individual
solvent reduction
plans.
Provide incentives and
goals to similar cost
centers.
Compare solvent usage
from like UOS's within
a given industry and
require justification
from higher users.
Evaluate potential
alternative cleaning
solutions.
Mandate implementation
of specific solvent
management techniques.
Conduct experiments to
determine minimum
amount needed for each
cleaning task.
Require plants to
conduct extensive,
short-term studies and
to commit to take
action based on
results.
Implement an employee
suggestion program.
Compile and share
information on the use
of cleaning solutions.
Mandate use where
appropriate.
7. Form a task force with
other plant managers to
compare cleaning
practices.
Compile and share
results of alternative
cleaning solution
tests. Mandate use
where appropriate.
4-8
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solvent on the test panel can also be evaluated qualitatively.
Simultaneous tests of the alternative and the existing solvent
are preferable to tests at different times.
Another approach would be to wipe each panel until the
cleanliness requirements are met. The ratio of required wipes
would be a gross measure of relative efficiency.
4.2.2 Plant Management Actions
As with testing for suitable alternative solvents, an
accounting system does not, in itself, provide a plant manager
with specific pollution information from a cleaning activity
(unit operation) in a cost center, nor may it always provide
incentive for him or her to take action. For example, if process
solvents are reused as cleaning solvents, there may be no usage
cost (although a line entry showing the amount used should still
be shown). A cost center manager will, however, likely react
even in the absence of any regulatory incentive, if the cost
alone is incentive to reduce the solvent usage in the expense
category. Further, if there are significant monthly
fluctuations, the manager may on his or her own initiative,
investigate to see how they can be reduced.
One action to focus reduction efforts is to require detailed
usage (and waste) records at the cleaning activity level within a
cost center. Such a specific analysis will likely be necessary
to provide guidance on practical remedial action, especially when
numerous cleaning activities are performed within a cost center.
Measurement or estimation of additives in the cleaning solvent
and contaminants in the collected solvent would also be necessary
to determine the actual VOC emissions, and these values are
likely to vary with the type of cleaning being performed.
Two approaches to conducting specific analyses at the
cleaning activity level are presented in Appendices C and D.
Appendix C describes the UOS concept defined as the ensemble
around which a material balance for cleaning can be performed.
Inputs for the material balance consist of the VOC fraction of
all solvents used for cleaning in the system. Assuming no
emissions are captured and measured, the outputs are the VOC
4-9
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content of collected solvent. Emissions are then calculated as
the difference between the inputs and outputs. Normalizing data
for like UOS's would allow comparison within a plant or among
plants within a company or an industry. Records may then be
maintained at the UOS level to document gains achieved with
subsequent emission reduction techniques and to ensure that the
gains are maintained. The approach in Appendix D is similar, but
the system boundaries may be more variable, and long term record
keeping, if any, would be maintained at the cost center level
rather than the UOS. Comparison of results for similar cleaning
activities would be more difficult under this approach.
Another way the accounting system could be used is to give a
manager of two similar cost centers a basis for comparing the
relative solvent usage by those centers. By comparing solvent
usage on the unit operation level, the manager could identify the
reason for differences and subsequently require action by the
larger user to reduce usage. Another option he or she has is to
provide incentives and goals to encourage both centers to reduce
manufacturing costs (solvent usage and disposal) and emissions.
Still another potential use of an established accounting
system is to involve plant managers throughout an industry. One
or more task forces could be formed to compare usage and work
practices among their facilities and publicize the best for each
of a variety of cleaning procedures.
After a cleaning task is targeted for reduction, the plant
may conduct tests to determine the minimum amount of solvent
necessary for the task and then stipulate that only that amount
will be allocated. Implementing an employee suggestion program
to encourage the submittal of cost-saving ideas is another
possible action.
4.2.3 State Agency Actions
Despite the number of possible cost and environmental
incentives for managers to conserve solvent, the cost of solvent
in some industries will remain insignificant compared to the cost
of labor and the value of enormously expensive parts, regardless
of how much solvent is used. The aerospace industry is a good
4-10
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example, and emissions from cleaning account for about 60 percent
of their total emissions.2 To effect solvent conservation in
such an industry (or in any industry where the data collected in
the solvent accounting system do not show acceptable improvement)
may require that the State mandate that industry undertake
specific solvent management techniques based on information
gained from the solvent accounting system. (Some period would be
required to ensure that the accounting system is providing valid
information before management could be expected to take action
based on its results.)
If direct comparisons among plants within an industry are
not possible because of differences in the ways that the cost
centers are constructed, the State may require detailed studies
be initiated using the UOS regimen explained in Appendix C.
Standardizing the system around which the material balance is
performed is essential to obtain data that would allow
comparisons within and perhaps even across industries, although
the latter has yet to be demonstrated in practice. Significant
differences would be cause for more detailed investigations.
Confirmation that the differences are unwarranted could result in
changes based on transfer of knowledge from plants that reduce
emissions from the more wasteful sources.
A State may also require that plants submit individual
solvent reduction plans. Development of such a plan would cause
each plant to closely evaluate current emissions and costs
associated with the solvent in order to project possibilities for
reductions. The American Automobile Manufacturer's Association
has suggested such an approach (see Appendix D). Again, for
these plans to be useful, the plant would need to evaluate
solvent usage on a UOS basis. (Note that there must be some
sensitivity to previous reductions by individual plants. A
State-imposed requirement for a defined "percent reduction" would
penalize companies that previously implemented solvent
conservation programs and reward the more wasteful plants.)
A third option is to require plants to conduct extensive,
short-term studies of major solvent uses and commit to take
4-11
-------
action based on results of the investigations. The State could
also use the information from one plant to target corrective
action at other plants with the same UOS's.
As a fourth option, the State may compile information on the
use of cleaning solutions for an industry and share it with other
plants. This action alone, of course, will not necessarily
result in reductions in emissions unless the State follows
through with subsequent requirements for action.
Finally, States could obtain and disseminate the results of
many company's studies of alternative cleaning solutions and,
where deemed practical, require companies to switch to
alternatives.
4.3 REFERENCES FOR CHAPTER 4
l. Dorfman, M., W. Muir, and C. Miller, INFORM. Environmental
Dividends: Cutting more chemical wastes. 1992. pp. 30-35.
2. Personal communication between Serageldin, M., EPA/CPB, and
Booth, V., EPA/CPB. 1992. Solvent accounting and
utilization procedures in the aerospace industry.
4-12
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5.0 COSTS OF INSTITUTING ACCOUNTING AND MANAGEMENT
5.1 PLANTWIDE CASE STUDY COSTS
This section presents costs for six of the case studies
described in Appendix E. Two plants provided costs for both the
accounting system and reduction techniques. One plant provided
only solvent accounting system costs. Three plants provided
qualitative cost information. Although accounting was conducted
at lower levels than the plant level (some at the UOS levels and
others at the department level), all of these plants reported
only collective, plantwide costs. Similarly, pollution reduction
techniques were implemented for individual unit operations, but
the plants reported only the plantwide usage and emission
reductions, and the plantwide sum of the costs or savings, for
all techniques.
Generally, the total capital investment (TCI) for a solvent
accounting system includes computer hardware and software
programs used to track usage, waste, and emissions. For three
plants, however, new software was all that was needed. One plant
provided the cost for its existing computer hardware.
Theoretically, the TCI for the reduction techniques
undertaken after the accounting system is online would include
the cost for changes in equipment to reduce usage, waste, and
emissions. In practice, however, none of the pollution reduction
techniques implemented by the surveyed plants required new
equipment.
Direct annual costs related to solvent accounting include
labor required for recording, entering, and analyzing cleaning
solvent data; annual training; and maintenance of the computer
system and software. Average 1991 wage rates for the labor
5-1
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requirements at these plants were based on reported 1992 and
1993 wage rates (excluding overhead) that were adjusted downward
by 4 percent per year to account for inflation. All labor costs
in this section are based on these wage rates and reported hours
shown in Appendix E for each plant.
Direct annual costs associated with actual pollution
reduction techniques include cleaning solvent usage and waste
disposal costs, emission tax charged by State or local air
quality management districts, labor required for new equipment or
changes in cleaning practices, and maintenance related to the new
equipment. Cost impacts associated with changes in production
were not considered.
Indirect annual costs for both solvent accounting systems
and reduction techniques were calculated as described earlier.
Computers and associated software are assumed to have a 10-year
life, and the marginal rate of return is assumed to be
10 percent. Therefore, the capital recovery factor (CRP) is
0.16275.
The remainder of this section discusses costs and savings
for six of the plants described in Appendix E. Of these, only
qualitative information was provided by plants A, D, and F, which
is discussed in Section 5.1.1. Accounting system costs for
plants C, E, and 6 are discussed in Section 5.1.2 and summarized
in Table 5-1. Costs associated with reduction techniques for
plants E and G are presented in Section 5.1.3 and Table 5-2. A
comparison with solvent accounting costs is also presented in
Section 5.1.3.
5.1.1 Qualitative Cost Information*'4
Facility A has not performed a cost analysis of its solvent
accounting system or of the impact of changes made to better
manage solvent. Plant management, however, believes that even if
the costs to implement and maintain the accounting system and
solvent management techniques are higher than the savings, the
difference is small and the benefits are worth the cost. This
conclusion is based on the following qualitative assessments.
5-2
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TABLE 5-1. SUMMARY OF SOLVENT ACCOUNTING COSTS
A. Total capital investment, $
1. Purchased equipment*
2. Installation11
3. Initial training
B. Direct annual costs, $/yr
1. Operating labor
recording
data entry
analysis
mp'n*'*fiflnrr
2. Training
3. Maintenance materials
C. Indirect annual costs, $/yr
1. Overhead
2. Administrative charges
3. Property tax
4. Insurance
5. Capital recovery
D. Total annual costs, $/yr
Facility C
160
32
252
451
5,199
2,790
2,790
0
1,109
0
11,888
6,467
9
4.5
4.5
_Z5
6,560
18,448
Facility E
2,200
c
_e
2,200
2,250
1,700
2,000
902
98
_9Q2
7,852
3,452
44
22
22
368
3,908
11,760
Facility G
2,500
c
1.208
3,708
5,400
9,449
1,700
N/A
36
N/A
16,585
9,929
74
37
37
620
10,697
27,282
N/A = Not available
Assumes taxes and freight are included in purchase costs.
bAssumed to be 20 percent of purchased equipment cost
Included in the purchased equipment costs.
5-3
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TABLE 5-2. SUMMARY OF POLLUTION REDUCTION TECHNIQUE COSTS
A.
B.
C.
D.
Total capital investment, $
Annual costs for cleaning"
1. Direct annual costs, $/yr
a. Cleaning solvent
b. Waste disposal
c. Emission fees/taxes
d. Cleaning labor
e. Training
f . Maintenance labor
g. Maintenance materials
2. Indirect annual costs, $/yr
Accounting system costs, $/yr°
Total annual cost, S/yr4
Facility E
0
(15,600)
0
(1,950)
N/A
N/A
0
0
N/A
(17,550)
11,760
(5,790)
Facility G
0
(8,000)
b
(138)
N/A
N/A
N/A
N/A
N/A
(8,138)
27,282
19,144
N/A = Not available
The annual costs are the incremental costs (or savings) that resulted after implementation of pollution
reduction techniques.
'Included in the cleaning solvent cost.
"See Table 5-1 for the derivation of accounting costs.
Total annual cost is the sum of the annual cost for the solvent accounting system and annual cost
(savings) for the pollution reduction techniques.
5-4
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Limitations on acetone, which is one solvent management
technique implemented, have reduced the purchase and waste
disposal costs for this solvent. Another change, replacing
Tipsolve, a proprietary cleaner composed of a mix of solvents,
with dibasic acid ester (DBE) to lower evaporation, also reduced
purchase and waste disposal costs. Plant management indicates
that cleaning labor costs have increased slightly as a result.
No equipment was purchased for the accounting system or to aid
reductions.
Plant management at Facility D also has not performed a cost
analysis, but it, too, provided qualitative information.
Facility D indicates that costs for the accounting system may
exceed any savings achieved during the first year of
implementation but maintains that will change within a few years.
Tracking data provided by the accounting system will help
identify areas where solvent usage, waste, and costs can be
reduced.
Facility F reports reduced usage and waste disposal and
associated costs due to its accounting system and solvent
reduction efforts. The plant estimates a combined annual cost
reduction of $1,000 to $1,500 for both usage and waste due to
solvent reduction techniques. Plant management indicates that
implementing the solvent accounting system has made employees
more conscious of solvent usage, and this awareness has
contributed to reductions.
5.1.2 Solvent Accounting Costs
Plants C, E, and G provided data used to estimate the costs
for solvent accounting systems. The data show both the TCI and
the annual cost do not depend on facility size.
The TCI included only the cost for computer software and
initial training to use the software because all three plants
installed the new software on existing computers. The TCI for
facilities E and 6, both with approximately 100 employees, was
estimated to be about $2,200 and $3,708, respectively. For
facility C, a larger plant (believed to be approximately
800 employees), the TCI was estimated to be only $451.
5-5
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Total annual costs for accounting systems range from about
$12,000 to $27,000 for the smaller Facilities E and G and $18,000
for Facility C, an overall average of $19,000/yr. Additional
detail about the procedures used to determine these costs for the
three plants is presented below.
5.1.2.1 Facility C.i>6 The total annual cost for the
solvent accounting system at Facility C was estimated to be a
little more than $18,000/yr. The accounting system was
implemented! in 1992 on existing computer hardware and from an
existing software package. The original cost for the existing
computer and software was $4,200. Because the plant already
owned this equipment and software, these costs were not included
as part of the cost of the accounting system. An initial labor
cost of $160 was incurred from in-house development of the
software program used. Installation was assumed to equal
20 percent of the development cost. The plant provided initial
training for operators regarding recording procedures at a cost
of $259. For analysis purposes, these initial labor costs were
treated as a capital cost.
As shown in Table 5-1, annual labor costs for operating the
accounting system include $5,199/yr for recording information,
$2,790/yr for data entry, and $2,790/yr for evaluating the data.
The cost for annual training is $l,109/yr. No maintenance costs
are associated with the computer software.
5.1.2.2 Facility E.7>8 As noted in Appendix E, Case
Study E, this facility has tracked cleaning solvent use since
1989. The tracking procedures have changed over the years; this
analysis presents the costs for the computerized system that was
implemented in 1991.
The TCI for the solvent accounting system was reported to be
$2,200 to develop and install the software system on an existing
computer. No training costs were associated with implementing
computerized accounting.
Annual operating labor costs for 1991 include $2,250 for
recording information, $1,700 for data entry, and $2,000 for
5-6
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annual analysis. Annual training for the employee who performs
data entry costs $98. Annual maintenance and material costs for
upkeep of the software system are $1,804. In summary, total
direct annual costs for the accounting system are $7,852/yr. As
shown in Table 5-1, total indirect costs are $3,908/yr, and the
total annual cost is $11,760.
5.1.2.3 Facility G.9'10 Although facility G first
implemented a solvent accounting system when the plant opened in
1985, this analysis presents the costs for the upgraded system
and procedure implemented in 1991.
The TCI for implementing and installing the computer
software on existing hardware was estimated to be $3,708, of
which $2,500 was for the purchase and installation of software
and $1,208 was for initial employee training. Operators, the
data entry employee, and the employee evaluating data were
trained.
Annual labor costs for the solvent accounting system include
$5,400 for data recording, $9,449 for data entry, and $1,700 for
data analysis. Annual training costs, which totaled $36 in 1991,
are incurred from the plant's annual training meeting and from
training new hires. Indirect costs for the solvent accounting
system are detailed in Table 5-1. The total annual cost for the
solvent accounting system is $27,282, with a direct cost of
$16,585 and an indirect cost of $10,697.
5.1.3 Cost of Pollution Reduction Techniques
Only two facilities, E and G, provided the cost of
implementing pollution reduction techniques; Facility C provided
partial costs. As shown in Table 5-2, Facility E spends
$ll,760/yr for its accounting system and saves $17,550/yr due to
pollution reduction techniques implemented, for an overall
savings. Facility G also provided information for both the
accounting system and pollution reduction technique costs; the
plant spends $27,282/yr on its accounting system and saves
$8,138/yr as a result of pollution reduction techniques. Plant
management at Facilities E, F, and G all indicate that the
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accounting system has made employees more conscious of solvent
usage, and this awareness has contributed to reductions.
5.1.3.1 Facility C.3-4 As discussed in Appendix E,
Facility C implemented a variety of reduction techniques before
initiating a complete solvent accounting system in April 1992.
The plant had maintained solvent disposal records for several
years, and cleaning wastes were the only source. The plant used
these records to show pollution reduction techniques resulted in
waste reductions of 35,000 gal for a cost savings of $100,000 in
1991. (Knowledge of the magnitude of waste generated also may
have spurred development of the pollution reduction techniques.)
Other cost savings also may have been achieved, but without
accounting records, they could not be documented. Those savings
in waste costs alone, though, exceed the cost of the current
solvent accounting system by about $75,000 annually. Eventually
the plant expects to use the accounting results to identify
additional areas where solvent use, waste, and costs can be
reduced.
5.1.3.2 Facility E.7-8 As discussed in Appendix E,
Facility E reduced VOC emissions from cleaning solvents two ways,
by limiting access to the solvents and switching to using glycol
ethers rather than methyl ethyl ketone (MEK) and methyl isobutyl
ketone (MIBK). As a result, the plant reported cleaning solvent
emissions were reduced by 6.5 tons per year (tons/yr) between
1988 and 1991. The plant did not report actual usage or waste
generation, instead, they assumed that the usage and emissions
reductions are equal. Therefore, there is no change in waste
generation. The plant did not indicate whether the pollution
reduction techniques affected labor requirements.
The reduction techniques did not involve any equipment
changes; thus, the TCI is zero. Unit costs for the glycol
ethers, MEK, and MIBK were all reported by the plant as $1.20/lb
at the time of the substitution in 1990. Assuming these unit
costs did not change in 1991, the usage reduction achieved a cost
savings of $15,600/yr. Waste disposal costs were assumed to be
5-8
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unchanged. The local air quality management district charges
$300/ton of VOC emissions, resulting in another savings of
$l,950/yr. The impact, if any, on labor costs was not provided.
In summary, the reduction techniques saved the plant $17,550/yr.
As shown in Table 5-2, these savings exceed the cost of the
solvent accounting system by nearly $5,800/yr.
5.1.3.3 Facility G.9-10 Facility G has tracked cleaning
solvent usage since the plant opened, this allowed the plant to
document cost reductions achieved with pollution reduction
techniques implemented in 1986 and 1987 (no reduction techniques
have been implemented since). The plant documented a reduction
in solvent and waste costs of $8,000 in 1987. The change in unit
costs since 1987 for the solvent and waste were not provided to
EPA; thus, the 1991 savings was assumed to be $8,000. Emission
fees ($300/ton) paid to the plant's air quality management
district declined from $150/yr to $12/yr, for a savings of $138.
The incremental cost of labor is unknown; as is that of the
overhead costs. Total savings from solvent reduction techniques
is $8,l38/yr. Since facility G spends $27,282/yr on its current
accounting system, the net annual cost is $19,144.
5.2 REFERENCES FOR CHAPTER 5
l. Office of Air Quality Planning and Standards Control Cost
Manual (4th ed.). u. S. Environmental Protection Agency.
Research Triangle Park, NC. Publication No. EPA 450/3-90-
006. January 1990.
2. Telecon. Randall, D., MRI, with Joyner, L., Hatteras
Yachts. July 24, 1992. Solvent accounting and management
procedures.
3. Telecon. Schmidtke, K., MRI, with Brown, G., Graphics
Technology International. August;, 11 and 14, 1992. Solvent
accounting and management procedures.
4. Telecon. Schmidtke, K., MRI, with Facility F. September l,
1992. Solvent accounting and management procedures.
5. Telecon. Schmidtke, K., MRI, with Irish, D., Flexcon
Corporation. August 11 and 17, 1992. Solvent accounting
and management procedures.
5-9
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6. Telecon. Schmidtke, K., MRI, with Irish, D., Flexcon
Corporation. March 3, 1993. Costs and impacts of solvent
accounting and management procedures.
7. Telecon. Schmidtke, K., MRI, with Facility E. August 27
and November 24, 1992. Solvent accounting and management
procedures.
8. Telecon. Schmidtke, K., MRI, with Facility E's consultant.
November 25, 1992. Costs and impacts of solvent accounting
and management procedures.
9. Telecon. Schmidtke, K., MRI, with Koenig, J., SupraCote,
Inc. September 2 and December 3, 1992. Solvent accounting
and management procedures.
10. Letter from Koenig, J., SupraCote, Inc., to Schmidtke, K.,
MRI. January 11, 1993. Costs and impacts of solvent
accounting and management procedures.
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APPENDIX A.
TERMS AND DEFINITIONS FOR SOLVENT CLEANING
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APPENDIX A.
TERMS AND DEFINITIONS FOR SOLVENT CLEANING
This Appendix presents a glossary of terms and definitions
used -in this report.
Cleaning activity
Physical removal of foreign material from substrate being
cleaned. Includes actions such as wiping, brushing, flushing, or
spraying.
Cleaning classification
For convenience, cleaning has been considered to have three
main classifications: (l) cleaning of external surfaces,
(2) cleaning of interior surfaces (i.e., containers), and
(3) cleaning of removable parts.
Cleaning of external surfaces
Solvent is applied to the "external surface" being cleaned
(as contrasted to the interior of tanks or pipes). Surfaces that
fall within this classification include rollers in printing
machines, wings of airplanes, floors, tables, and walls. The
"cleaning activities" applied to the external surface may include
mopping, brushing, or spraying and use "cleaning tools" such as
rags, brushes, mops, or spraying equipment.
Cleaning of internal surfaces/containers
Solvent is applied to an interior surface for cleaning.
Surfaces may include the inside of tanks/vessels, batch reactors,
columns, heat exchangers, paint spray booths, and fuel tanks. The
"cleaning activities" applied may include flushing, agitation,
spraying, and mopping or brushing. Any combination of activities
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may be used, depending on the shape and size of the "unit
operation" and on the type residue that is being removed.
Cleaning of parts
Solvent engulfs the entire surface of the item (part) as it
is dipped in a container of solvent, or the part is cleaned above
the container by a cleaning activity such as spraying or wiping.
Equipment, the "unit operation," where this might take place,
includes part washers, batch-loaded cold cleaners, ultrasonic
cleaners, and spray gun washers.
Cleaning practices
A repeated or customary action that is specific to an
industry. An example is nightly maintenance of a spray booth in
an automobile assembly plant
Cleaning tool
An item used to aid cleaning, such as wiping rags, brushes,
scrapers, or water jets.
Closed-loop recycling (in-process recycling)
Reuse or recirculation of a chemical material within the
boundaries used to develop a material balance around a "unit
operation system. " A recovery or reclamation (R or R) unit
operation may be within the boundaries selected for the primary
unit operation system if it is:
1. Solely dedicated. The chemical is reused only for
cleaning the primary unit operation.
2. Physically integrated. The R or R operation is
connected to the primary unit operation by means of piping, so
that it is not possible to perform the material balance around
the primary unit operation system without including it.
Hazardous Air Pollutant (HAP)
Any of almost 200 substances identified as air toxics in
Section 112 of the Clean Air Act Amendments of 1990.
In-process recycling
(See closed-loop recycling).
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flushing
Line flushing is the procedure of completely cleaning out a
large paint circulating system such as those found at auto
assembly plants. The system includes the paint mix tanks and
perhaps hundreds of feet of pipe or piping. This procedure is
only necessary when a system is inadvertently contaminated or for
a routine color change.
Although the system is essentially closed loop, some losses
can occur during the flushing (i.e. through various vents, from
transfer operations and from the paint mix tanks) . In the
information supplied to the Agency, automobile assembly plants
with closed loop systems estimated a 10 percent loss from the
line flushing operation, independent of the solvent used, but
they provided no data or rationale to support the estimates.
Onsite recycling
An R or R unit operation located within the plant boundaries
from which clean solvent is returned to a process other than that
which generated the waste solvent. A material balance for the R
or R unit operation (distillation, filtration, etc.) should be
developed independently.
See "storage containers." (Emissions during cleanup of the R
or R unit operation should not be) overlooked when determining the
long-term solvent efficiency of the unit.)
Offsite recycling
An R or R unit operation system located outside of the plant
boundaries .
Pollution prevention
Practices or process changes that decrease or eliminate the
creation of emissions (or wastes) at the source. Such prevention
techniques include use of new materials, modification of
equipment, and changes in work practices.
Product substitution /
Replacement of any product or raw material intended for an
intermediate or final use with another. This substitution is a
source reduction activity if either the VOC emissions or the
quantity of waste generated is reduced.
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Purging
The process wherein individual paint applicators and
portions of paint delivery lines are emptied of one color paint,
cleaned, and filled with another. This is a common cleaning
practice in the automobile assembly industry.
Reclaim
"Reclaim" means a material is processed or regenerated to
recover a usable product. (See recycle).
Recovery or regeneration (R or R) unit operation
A device for purifying solvent that may use any of a variety
of techniques, including extraction, distillation, filtration,
adsorption, or absorption.
Recycle
"Recycled" means used, reused, or reclaimed
(40 CFR 261.l(b)(7)). A material is "used or reused" if it is
either employed as an ingredient (including its use as an
intermediate) to make a product. For example, when solvent
recovered by distillation is reused in the plant.
Reuse
See "used."
Source reduction
Any activity or treatment that reduces or eliminates the
generation of VOC emissions (or waste), including product
substitution or elimination and pollution prevention.
Storage container
Emissions from storage containers are to be included in a
material balance.
Treatment
Destruction or degradation of waste using techniques such as
combustion or neutralization to produce material that is less
toxic and more environmentally benign. (See recycle).
Unit operation (UP)
An industrial operation, classified or grouped according to
its function in an operating environment. Examples include
distillation columns, paint mixing vessels (tanks), spray booths,
parts cleaners and printing machines. A unit operation may
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consist of one or more items of equipment, e.g., both a reactor
and a mixing vessel or several mixing vessels. There may be
considerable variation in the type of unit operations from one
industry to another. (See unit operation system.)
Unit operation system (UPS)
The ensemble of equipment around which a material balance is
performed. A UOS includes all possible points/sources that could
result in losses to the atmosphere as a result of its being
cleaned, including losses during dispensing of solvent, losses
from residual solvent on or in cleaning tools (such as rags),
losses from solvent storage, etc. An item of equipment used for
cleaning parts by definition is a unit operation, therefore,
carry-out losses during removal of cleaned parts should be
considered in a material balance.
Used (or reused)
A material is "used or reused" if it is employed as an
ingredient (including use as an intermediate) in an industrial
process to make a product (for example, in purifying a waste
solvent, distillation bottoms from one column may be used as
feedstock in another).
Volatile Organic Compounds (VOC)^
[NOTE: This definition may change. The Code of Federal
Regulations (40 CFR 51.100 [s]) presents the current legal
definition.] Any compound of carbon, excluding carbon monoxide,
carbon dioxide, carbonic acid, metallic carbides or carbonates,
and ammonium carbonate, which participates in atmospheric
photochemical reactions.
1. This includes any such organic compound other than the
following, which have been determined to have negligible
photochemical reactivity: methane; ethane; methylene chloride
(dichloromethane); 1,1,1-trichloroethane (methyl chloroform);
l,l,l-trichloro-2,2,2-trifluoroethane (CFC-113);
trichlorofluoromethane (CFC-11); dichlorodifluoromethane
(CFC-12); chlorodifluoromethane (CFC-22); trifluoromethane
(FC-23); 1,2-dichloro 1,1,2,2-tetrafluoroethane (CFC-114);
chloropentafluorethane (CFC-115); 1,1,1-trifluoro
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2,2-dichloroethane (HCFC-123); 1,1,1,2-tetrafluoroethane
(HFC-134a); 1,1-dichloro l-fluoroethane (HCFC-14lb); 1-chloro
1,1-difluoroethane (HCFC-142b); 2-chloro
1,1,1.,2-tetrafluoroethane (HCFC-124); pentafluoroethane
(HFC-125); 1,1,2,2-tetrafluoroethane (HFC-134);
1,1,1-trifluoroethane (HFC-143a); 1,1-difluoroethane (HFC-152a);
and perfluorocarbon compounds which fall into these classes:
(a) Cyclic, branched, or linear, completely fluorinated
alkanes;
(b) Cyclic, branched, or linear, completely with
fluorinated ethers with no unsaturations;
(c) Cyclic, branched, or linear, completely fluorinated
tertiary amines with no unsaturations; and
(d) Sulfur containing perfluorocarbons with no
unsaturations and with sulfur bonds only to carbon and fluorine.
2. For purposes of determining compliance with emission
limits, VOC will be measured by the test methods in the approved
State implementation plan (SIP) or 40 CFR Part 60, Appendix A, as
applicable. Where such a method also measures compounds with
negligible photochemical reactivity, these negligibility-reactive
compounds may be deducted from the reported VOC if the amount of
such compounds is accurately quantified, and such exclusion is
approved by the enforcement authority.
3. As a precondition to excluding these compounds as VOC or
at any time thereafter, the enforcement authority may require an
owner or operator to provide monitoring or testing methods and
results demonstrating, to the satisfaction of the enforcement
authority, the amount of negligibly-reactive compounds in the
source's emissions.
4. For the purposes of Federal enforcement for a specific
source, the EPA shall use the test method specified in the
applicable EPA-approved SIP, in a' permit issued pursuant to a
program approved or promulgated under Title V of the Act, or
under 40 CFR Part 51, Subpart I or Appendix S, or under 40 CFR
Parts 52 or 60. The EPA shall not be bound by any State
determination as to appropriate methods for testing or monitoring
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negligibly-reactive compounds if such determination is not
reflected in any of the above provisions.
Waste minimization
Means the reduction, to the extent feasible, of hazardous
waste that is generated or subsequently treated, stored or
disposed. It includes any source reduction or recycling activity
undertaken by a generator that results in either (1) the
reduction of total volume or quantity of hazardous waste, or
both, so long as such reduction is consistent with the goal of
minimizing present and future threats to human health and the
environment. In order of preference there are: source
reduction, recycling, and treatment.
Work practice
This term is reserved for specific human activities within
industry that lead to a reduction in VOC emissions (or waste).
The activities include increased operator training, management
directives, segregation of the waste solvent, and practices that
lead to a reduction in cleaning frequency. It does not include
the .use of specialized equipment, such as solvent dispensers.
REFERENCES FOR APPENDIX A
1. 40 CFR Part 51, Vol. 57, No. 22, February 3, 1992.
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APPENDIX B.
REVIEW AND SUMMARY OF STATE AND LOCAL CLEANING REGULATIONS
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APPENDIX B.
REVIEW AND SUMMARY OF STATE AND LOCAL CLEANING REGULATIONS
B.I REVIEW OF STATE AND LOCAL REGULATIONS ON SOLVENT CLEANING
A survey of State and local agencies was conducted to obtain
information on existing cleaning solvent regulations.
Information was received from 45 agencies. Only 13 have specific
requirements on the use of cleaning solvents, and each of these
is summarized below. A list of all agencies have provided
information is in Section B.2 of this appendix.
B.l.l Alabama. Jefferson County^
All regulated surface coating facilities are subject to
recordkeeping requirements for cleaning solvents. For each
solvent, a plant must record the daily amount used; the density;
and the VOC, solids, water, and exempt VOC weight and volume
fractions.
B.1.2 Alabama. Huntsville^
Surface coating regulations require maintenance of daily
records on the quantity in gallons of all organic solvents used
for wash or cleaning.
B.1.3 Arizona3
All VOC emissions from solvent washings shall be considered
in the emission limitations for a facility unless the solvent is
directed into containers that prevent evaporation to the
atmosphere.
B.1.4 California. Bay Area4
Surface preparation, cleaning, and removal of coating, ink,
or paint in surface coating and other specified industries is
regulated under this rule. Specifically, the regulations require
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that: (1) no open containers be used to store or dispose of cloth
or paper impregnated with organic compounds, (2) no open
containers be used to store spent or fresh organic compounds, and
(3) no organic compounds be used to clean spray equipment unless
some mechanism for collecting the cleaning compounds and
minimizing their evaporation to the atmosphere is used.
B.I.5 California. South Coast5
This rule regulates cleaning during production, repair, and
maintenance of parts, products, tools, machinery, equipment, and
general work areas, as well as storage and disposal of
VOC-containing materials used in solvent cleaning. Facilities
affected by this rule include manufacturing plants, printing
presses, shipyards, motor vehicle assembly plants, and repair and
refinishing facilities such as auto garages, auto body shops, and
workshops for repairing buses, aircraft, trains, and trucks.
Four broad categories of VOC and exempt compound emissions
from solvent cleaning are regulated under this rule. These are
emissions from surface preparation, repair and maintenance
cleaning, cleaning of application equipment, and use of
remote-reservoir cold cleaners. The main requirements specified
in this rule are:
l. The VOC content and partial pressure limits on solvents
used for:
a. Substrate cleaning during the manufacturing process and
surface preparation for coating, adhesives, or ink applications;
b. Repair and maintenance cleaning;
c. Cleaning coating and adhesives application equipment;
d. Cleaning polyester resin application equipment;
e. Cleaning inks and varnishes application equipment in
screen printing, lithographic printing, and other graphic arts
printing operations; and
f. Manufacturing and maintenance cleaning of electronic
assemblies;
2. Specific cleaning methods and devices must be used to
clean;
B-2
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3. Compliance with the rule may be achieved by using
collection and control systems, subject to certain performance
standards;
4. Atomizing any solvent into open air is prohibited;
5., The VOC-containing materials used in solvent cleaning and
cloth and paper moistened with solvents shall be stored in
nonabsorbent, nonleaking containers that shall be kept closed at
all times except when filling or emptying; and
6. Daily records on the amount of solvent used are required.
Additionally, cleaning associated with semiconductor
manufacturing, aerospace assembly and component manufacturing,
coating and ink manufacturing, and motor vehicle assembly line
coating are regulated under separate regulations.
B.1.6 California. Ventura County
This rule regulates the use of cleaning solvents for paper,
fabric, and film coating; surface coating of metal parts and
products; aerospace assembly and component manufacturing;
polyester resin material operations; motor vehicle and mobile
equipment coating; graphic arts; adhesives; and semiconductor
manufacturing. The county also has a proposed rule addressing
general cleaning. The specific requirements per industry are
listed below.
B.I.6.1 Paper. Fabric, and Film Coating.
1. Limit VOC content in cleaning solvents to 200 grams per
liter (g/L) (1.7 Ib/gal) of solvent; and
2. Maintain daily records of solvent used by type of solvent
and corresponding State identification number.
B.I.6.2 Surface Coating of Metal Parts and Products
1. Limit VOC content of solvent used for surface preparation
to 200 g/L (1.7 Ib/gal) of solvent;
2. Use a solvent with a VOC content less than 200 g/L
(1.7 Ib/gal) for cleaning coating operations equipment or use a
solvent with a vapor pressure less than 45 millimeters of mercury
(mm Hg) (1.8 in. Hg) and flush the solvent through the equipment
into a closed container; and
B-3
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3. Maintain manufacturers' specifications on solvents used
for equipment cleaning and surface preparation and maintain daily
records on type of solvent, reactive organic compounds (ROC)
content of solvents in g/L, volume of solvent used, and composite
vapor pressure of solvent and how it was determined.
B.l.6.3 Aerospace Assembly and Component Manufacturing
1. Limit VOC content of solvent used for surface preparation
to less than 250 g/L (2.1 Ib/gal) of solvent;
2. Clean guns in an enclosed gun washer; and
3. Maintain daily usage records.
B.l.6.4 Polyester Resin Material Operations. Limit use on
lines, brushes, spray equipment, and personnel of cleaning
materials containing greater than 200 g/L (1.7 Ib of VOC/gal) of
material as applied, or where the initial boiling point of the
cleaning agent is less 190°C (370eP), to less than 57 L (15 gal)
per calendar week unless a reclamation process is in place.
B.l.6.5 Motor Vehicle and Mobile Equipment Coating
Operations. Maintain monthly records consisting of the following
information:
1. Identification of each solvent and its uses;
2. ROC content of each solvent in g/L; and
3. Volume of solvent used; if purchasing records are used
for this, then manifests and recycling records must also be
maintained.
B.l.6.6 Graphic Arts. Limit vapor pressure to less than
33 mm Hg (1.3 in. Hg) for all solvents and:
1. Limit VOC content to 450 g/L (3.8 Ib/gal) for substrate
surface cleaning;
2. Limit VOC content to 750 g/L (6.3 Ib/gal) for repair and
maintenance cleaning;
3. Limit VOC content to 950 g/L (7.9 Ib/gal) for coating and
adhesives equipment cleaning;
4. Limit VOC content to 800 g/L (6.7 Ib/gal) for radiation
curing ink removal cleaning;
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5. Limit VOC content to 800 g/L (6.7 Ib/gal) for ink
application equipment cleaning from lithographic and letterpress
printing, and 450 g/L (3.8 Ib/gal) from other printing; and
6. Limit VOC content to 200 g/L (1.7 Ib/gal) for all other
cleaning operations. '
B.I.6.7 Adhesives.
1. Limit VOC content in solvent used for surface preparation
to less than 200 g/L (1.7 Ib/gal) of solvent; and
2. Clean coating application equipment in an enclosed
gunwasher with solvent with a vapor pressure less than 45 mm Hg
(1.8 in. Hg).
B.I.6.8 Semiconductor Manufacturing.
1. Subject the solvent cleaning stations to degreasing
regulations; and
2. Limit VOC content in solvent used for surface preparation
to less than 200 g/L (1.7 Ib/gal) of solvent.
In addition, Ventura County also has the following
freestanding requirements:
l. Emissions of ROC's (Reactive Organic Compounds) from
cleaning of any article, machine, or equipment should be included
with other emissions of that type of emissions in order to
determine compliance with Rule 66; and
2. Proposed Rule 317 focuses on substitution and
reformulation of cleaning solvent as a means of reducing ROC
emissions. The regulatory alternatives proposed include:
a. Use of closed containers for all cleaning activities;
b. Vapor pressure and ROC content limits on all cleaning
solvents; and
c. Prohibition of certain cleaning activities, including
flushing solvent from a solvent container greater than 0.47 L
(16 fluid ounces) unless the used solvent is collected in a
container; soaking objects in a container that is open except
when depositing objects; wipe cleaning where the solvent drips
from the materials, unless it is collected; atomizing solvent
into open air; and removing solvents from objects with compressed
air.
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B.l.7 Kansas7
Rule 28-19-73 requires most miscellaneous metal parts and
products and metal furniture facilities with total VOC potential
emissions greater than 2.72 Mg/yr (3 tons/yr) to keep daily
records of the type, density, and amount of solvent used for
purge and equipment cleaning. Automobile, light duty truck, and
metal car manufacturing plants; plants that perform customized
top coating of automobiles and trucks; and automobile refinishing
plants are exempted.
Rule 28-19-76 regulates the use of cleaning solvents at
lithographic printing major sources (VOC potential emission rate
^91 Mg/yr (.^100 tons/yr]). If such sources use cleaning solvents
containing VOC's, the solvent container must be tightly covered
during transport and storage, and cleaning rags used in
conjunction with cleaning solvents must be placed, when not in
use, in tightly closed containers and collected for proper
disposal or recycle. Furthermore, solvent must be extracted from
the rags prior to laundering, and monthly records on the quantity
of cleaning solvents used must be maintained.
B.1.8 Michigan. Wayne County
This rule requires that paint manufacturing equipment and
paint shipping containers be cleaned by methods and materials
that minimize the emission of VOC's. Such methods and materials
shall include one of the following:
1. Hot alkali or detergent cleaning;
2. High-pressure water cleaning; or
3. Cleaning using an organic solvent if the equipment being
cleaned is completely covered or enclosed, except for an opening
that is no larger than necessary to allow for safe clearance
based on the method and materials being used.
In addition, the wash solvent shall be stored only in closed
containers, unless it is demonstrated to be a safety hazard, and
disposed of in a manner such that not more than 20 percent, by
weight, is allowed to evaporate into the atmosphere.
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B.1.9 Missouri9
Cleaning solvents containing voC's are regulated in offset
lithographic, flexographic, and rotogravure printing operations.
The cleaning solvents must be kept in a tightly covered tank or
container during transport and storage, and the cleaning cloths
used with the cleaning solvents must also be placed in tightly
closed containers when not in use and while awaiting disposal.
The cleaning cloths should be properly cleaned and disposed of
and processed in such a way that as much of the solvent as
possible is recovered for further use or is destroyed. Cleaning
and disposal methods must be approved by the director, -and an
owner/operator may use an alternative method only if he or she
can demonstrate that the emission reduction is significant and
the method is approved by the director. Each printer subject to
this regulation is required to maintain records on the quantity
of cleaning solvents used monthly.
B.I.10 Ohio. Dayton10
This rule regulates organic material emissions from
activities using photochemically reactive materials. The use of
these materials in cleaning is specifically included in this
rule. Emissions from cleaning activities must be included in the
calculation of amount of photochemically reactive compound
emissions. These emissions have set daily and hourly limits, and
the requirements in Dayton specifically include cleaning
emissions in the compliance determination process.
B.I.11 Pennsylvania. Allegheny County11
The regulation restricts total VOC emissions from surface
coating processes (and associated cleaning) to 1.4 kg/hr
(3 Ib/hr), 7 kg/d (15 Ib/d), or 2,355 kg/yr (2.7 tons/yr).
Plants are required to keep daily records of the quantity,
composition, and density of solvents used for cleaning.
B.1.12 Tennessee. Metropolitan1
The State includes emissions of cleaning solvents in the
total facility emissions. Good work practices, use of solvents
that result in low VOC emissions, and daily and annual records of
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solvent use, including cleaning, are required for plants
manufacturing miscellaneous metal parts and products.
B.l.13 Wisconsin13
The State requires that good operating procedures for
solvents be used in cleaning. Recordkeeping, including daily
usage and VOC content, is required at facilities with air
emissions of 0.25 ton/d (0.23 Mg/d) or more on any one day of
operation or 50 tons/yr (45 Mg/yr) or more of all primary air
contaminants. Wash solvents for cured and air-dried coatings are
also regulated. Unless used wash solvent is collected in
containers that prevent evaporation, VOC emissions from solvent
washings will be considered in the emission limitations set for
cured and air-dried coatings.
B.2 SUMMARY OF STATE AND LOCAL REGULATIONS ON SOLVENT CLEANING
Typical requirements in the State and local regulations
described above for cleaning using organic solvents include:
1. Limits on the VOC content and partial pressure of
cleaning solvents;
2. Daily or monthly records of solvents;
3. Storage of waste solvent in closed containers; and
4. Equipment cleaning while completely covered or enclosed.
In addition, the regulations:
1. Prohibit specific cleaning methods and devices; and
2. Restrict or prohibit certain cleaning activities.
This section summarizes responses to an information request
that was sent to STAPPA/ALAPCO for distribution to State and
local agencies. A total of 44 agencies responded to the request
between July 1992 and February 1993. Information about proposed
Rule 1171 in California's South Coast Air Quality Management
District is also summarized.
The information is presented in three tables. Table B-l
identifies whether the agency regulates cleanup solvents,
indicates the actions or industries that are regulated, and
summarizes the regulatory requirements. Table B-2 summarizes how
cleaning is addressed in the permitting process, the aspects of
cleaning checked during plant inspections, and the plans for
B-8
-------
future cleaning-solvent regulations. Table B-3 presents
suggestions from the agencies for EPA guidance on cleanup solvent
emission control techniques, the types of unit operations cleaned
at inspected plants, and available case study information on
control techniques.
Listed below are definitions for all of the acronyms that
appear in the three tables:
1. VOC: Volatile Organic Compound;
2. ROC: Reactive Organic Compound;
3. MSDS: Material Safety Data Sheet;
4. NPPA: National Fire Protection Association;
5. BARCT: Best Available Retrofit Control Technology;
6. RACT: Reasonably Available Control Technology; and
7. BACT: Best Available Control Technology.
B-9
-------
TABLE B-l. SUMMARY OF STATE QUESTIONNAIRE RESPONSES
State
Alabama, Jefferson
County
Alabama,
Huntsville
Alabama, State
Arizona, State
Arkansas, State
California, Lassen
County
California, State*
Cleanup solvent
specific regs?
Yes
Yes
No
Yes
No
No
No
What is regulated?
All regulated surface coating
facilities.
Coating line wash and
cleanup associated with
surface coating.
All volatile organic
compound (VOC) emissions
from solvent washing shall
be considered in emission
limitations unless solvent is
directed into containers that
prevent evaporation.
Specific requirements
Daily records of all cleanup solvents.
f
Record of daily quantity in gallons of all
organic solvents used for wash or cleanup.
NA
B-10
-------
TABLE B-l. (continued)
State
California, South
Coast
California, Bay
Area
Cleanup solvent
specific regs?
Yes, Proposed
Rule 1171
Yes
What is regulated?
Cleaning during production,
repair, or maintenance of
parts, tools, machinery,
equipment or general work
areas, as well as to all
persons who store and
dispose of VOC-containing
materials used in solvent
cleaning operations.
Facilities affected by this
rule include: manufacturing
plants; printing presses;
shipyards; motor vehicle
assembly plants; repair and
refinishing facilities such as
auto garages, auto body
shops, and workshops for
the repair of buses, aircraft,
trains and trucks.
All surface preparation;
cleanup; coating, ink, and
paint removal in surface
coating and other specified
industries.
Specific requirements
Sets limits on solvents used for substrate
cleaning ^"rina manufacturine process and
of ink aRBlicatjpp? to no more than 200 s
VOC/L (1.7 Ib/gal) of material being
used; establishes limits for solvent used
for repair and maintenance cleaning that
the solutions used should not have a VOC
content of more than 850 g/L (7.1 Ib/gal)
of material and a VOC composite partial
pressure of more than 20 mm Hg (0.79 in.
Hg) at 20°C (68°F); establishes limits for
solvents used for cleanine coating and
adhesives application eauipment to be no
more 950 g VOC/L (7.9 Ib/gal) of
material and VOC composite partial
pressure of 35 mm Hg (1.4 in. Hg) at
20° C (68°F); establishes limits for
solvents used for cleanine inks or
varnishes apolication equipment in screen
plating shall not have a VOC content of
more than 1,070 g/L (8.9 Ib/gal) of
material and a VOC composite partial
pressure of more than 5 mm Hg (0.20 in.
Hg) at 20'C (68°F), in lithographic
printing the VOC content should not
exceed 850 g/L (7.1 Ib/gal) of material
and a composite partial pressure of more
than 25 mm Hg (0.98 in. Hg) at 20°C
(68°F), and all others should not have a
VOC content of more than 100 g/L (0.83
Ib/gal) of material and VOC composite
partial pressure of more than 3 mm Hg
(0.12 in. Hg) at 20°C (68°F); and
requires use of specific cleanup devices
and methods.
No open containers can be used for the
storage or disposal of cloth or paper
impregnated with organic compounds; no
open container storage of spent or fresh
organic compounds; and no usage of
organic compounds for the clean-up of
spray equipment unless equipment for
collection of the cleaning compounds and
minimizing its evaporation tn the
atmosphere is used.
B-ll
-------
TABLE B-i. (continued)
State
Cleanup solvent
specific regs?
What is regulated?
Specific requirements
California, Ventura
County
Yes
Paper fabric and film
coating, surface coating of
metal parts and products,
aerospace assembly and
component manufacturing,
polyester resin material
operations, motor vehicle
and mobile equipment
coating operations, and
graphic arts. Proposed rules
include: adhesives,
semiconductor manufac-
turing, and general cleanup
operations.
Paper, Fabric and Film Coating
- limit usage of cleanup solvents to 200 g
of VOC per liter of solvent or the
reactive organic compound (ROC)
emissions from cleanup are < 120 g/L
(< 1.0 Ib/gal) of solvent used, or the
emissions are collected and reduced.
- m«jpt«in daily records on the amount of
cleanup solvent used and its state I.D.
number.
Surface Coating of Metal Parts and
Products.
- limit use of equipment cleanup solvents
to <200 g ROC/L unless: the spray
equipment is cleaned in a solvent
container that prevents evaporation, the
cleaned equipment is drained and the
returned solvent is stored in a container
that prevents evaporation, or the
composite ROC vapor pressure of the
solvent is <45 mm Hg (1.8 in. Hg) at
20°C (68°F).
No ROC-containing solvents can be
used for substrate surface cleaning.
coating operation equipment cleaning
<200 g/L (1.0 Ib/gal) or use a solvent
with a vapor pressure less than 45 mm
of Hg (1.8 in. Hg) and flush solvent
through equipment into a closed
container.
- maintain manufacturer's specification
sheets on solvents used for equipment
cleaning and surface preparation
cleaning.
- maintain records on a daily basis for the
following: type, ROC content of
solvent in g/L, volume of solvent used,
composite vapor pressure of solvent and
how it was determined.
B-12
-------
TABLE B-l. (continued)
State
Cleanup solvent
specific tegs?
What is regulated?
Specific requirements
California, Ventura
County (cont'd)
Aerospace Assembly and Component
Manufacturing.
- surface cleaning solvents must contain
<200 g ROC/L (1.7 Ib/gal) or have a
vapor pressure :£ 25 mmHg
(0.98 in. Hg) at 20eC (68°F).
- cleaning must be performed in an
enclosed system or enclosed gun
washer.
- closed containers shall be used for
disposal and storage of
solvent-containing materials used for
cleanup.
- maintain usage records, along with
MSDS, on a daily basis.
Polyester Resin Material Operations
- cleaning material used on lines, rollers,
brushes, spray equipment, and personnel
and containing >200 g VOC/L of
material as applied (1.7 Ib/gal), or
where the initial boiling point is less
than 190'C (374°F) shall be limited in
use to <57 L (< IS gal) per calendar
week unless a reclamation system is in
place.
- all materials containing ROC's for
cleaning shall be in closed containers.
- generate weekly reports that list the
manufacturer, product number, amount
and application method for each
cleaning material used, reclaimed, or
recycled.
B-13
-------
TABLE B-l. (continued)
State
Cleanup solvent
specific regs?
What is regulated?
Specific requirements
California, Ventura
County (cont'd)
Victor Vehicle and Mobile Equipment
Boating Operations
closed containers shall be used to store
solvent-containing materials from
surface cleanup. Containers shall be
nonabsorbent.
- Organic compounds will not be used for
spray equipment cleanup unless:
- an enclosed gun washer or low
emission spray gun cleaner is used for
cleaning.
- the composite vapor pressure of
organic compounds is <45 mm Hg
(1.8 in. Hg) at 20°C (68°F).
- no substrate surface cleaning materials
with a ROC content of > 200 g/L
(1.7 Ib/gal) shall be used.
- all ROC-containing materials shall be
kept in closed containers when not in
use.
- MSDS on substrate surface cleaning and
application equipment cleaning showing
a monthly basis, the following:
- I.D. of each solvent and its uses.
- ROC content of each solvent, gallons
per liter.
- volume of solvent used; if purchase
records are used, then manifests and
recycling information should also be
Proposed Categories
Adhesives
- surface preparation < 200 g/L
(1.7 Ib/gal).
- coating application equipment cleaning:
- use enclosed gun washer and solvent
with vapor pressure < 45 mm Hg
(<1.8in. Hg).
Semiconductor Manufacturing
- solvent cleaning stations subject to
degreasing regs.
- surface preparation < 200 g/L
(1.7 Ib/gal).
- coating application equipment
cleaning use of solvents with a
vapor pressure < 33 mm Hg
(1.3 in. Hg) at 20°C (688F).
B-14
-------
TABLE B-l. (continued)
State
California, Ventura
County (cont'd)
Colorado, State
Colorado, Denver
City/County
Cleanup solvent
specific regs?
No
NA
What is regulated?
~
Cold cleaning and vapor
degreasing are regulated.
NA
Specific requirements
Rule 66 - Organic Solvents
- emissions of ROC's to the atmosphere
from cleanup with photochemically
reactive solvents of any article,
machine, equipment, should be included
with other emissions of that type of
emissions in order to determine
compliance.
Graphic Arts
- cleaning operations are limited to: wipe
cleaning, remote reservoir cold cleaner,
spray bottles with 0. 125 L (0.03 gal) or
less of solvent applied without
propellents or, using a closable solvent
container.
- maintain daily records showing types of
solvents used. Maintain monthly
records showing the amount of solvents
used and VOC content and density of
each.
Proposed Rule 317
- Focus on cleanup solvent substitution
and reformulation as a means of
reducing ROC emissions. The
regulatory alternatives discussed include:
- closed containers.
- vapor pressure limits of not greater
than 20 mm Hg (0.79 in. Hg) at
20°C (68 °F) and ROC content limits
not greater than 200 g ROC/L
(1.7 Ib/gal) of cleaning solvent.
- Prohibit certain cleaning methods:
- solvent flushing from a solvent
container greater than 0.47 L
(16 fluid ounces) unless collected in a
container.
- soaking of objects in a container that
is open except when depositing or
removing objects.
- wipe cleaning where the solvent drips
from the material unless collected.
- atomizing of solvent into open air.
- removing solvent from objects with
compressed air.
NA
B-15
-------
TABLE B-l. (continued)
State
Florida,
Jacksonville
Georgia, State
Indiana, Evansville
Indiana, State
Iowa, State
Iowa, Polk County
Kansas, State
Kentucky, State
Louisiana, State
Maine, State
Maryland,
Baltimore
Michigan,
Wayne County
Minnesota, State
Cleanup solvent
specific regs?
No
No
No
No
No
No
Yes
No
No
No
No
Yes
No
What is regulated?
Cold cleaning and
conveyorized degreasing are
regulated.
Miscellaneous metal coating
One regulation for miscel-
laneous metal parts and
products and metal furniture
and another for lithographic
major sources.
Solvent metal cleaning is
regulated.
Paint Manufacturers
> 18,900,000 L (500,000
gal) production.
Specific requirements
The amount and VOC content of each
washup solvent.
Specific handling methods for any source
emitting > 15 lb VOC per day.
Miscellaneous metal parts - Most facilities
with a VOC potential emission rate
(including cleaning solvents) equal to or
greater man 3 tons/yr shall keep daily
records of the type, density, and amount
of solvent used for purge and equipment
cleaning. Some types of plants are
exempt.
Lithographic printing If employing
cleanup solvent containing VOC: the
solvent container is tightly covered during
transport and storage; cleanup rags used in
conjunction with cleanup solvent are
placed, when not in use, in tightly closed
containers and collected for proper
disposal or recycle. Requires that the
solvent be extracted from rag before
laundering; and monthly records be
maintained on the quantity of cleanup
solvent used.
Maintain daily records of washup solvent
used and VOC content of each.
Mixing tanks and paint shipping container
cleaning are regulated with limits on VOC
content.
B-16
-------
TABLE B-l. (continued)
State
Missouri, State
Montana, State
Nebraska, State
Nevada,
Washoe County
North Carolina,
Buncombe County
North Carolina,
State
North Carolina,
Forsyth County
Cleanup solvent
specific regs?
Yes
No
No
No
No
No
No
What is regulated?
Lithographic, rotogravure
and flexographic printing.
Specific requirements
Offset lithographic printing -- If the
operation uses cleanup solvents containing
VOCs: the cleanup solvents are kept in
tightly covered tanks or containers during
transport and storage; the cleaning cloths
used with the cleanup solvents are placed
in tightly closed containers when not in
use and while awaiting offsitc
transportation. The cleaning cloths should
be properly cleaned and disposed of; are
processed in a way that as much of the
solvent as practical is recovered for
further use or destroyed. Cleaning and
disposal methods shall be approved by the
director, and an owner or operator may
use an alternate method of reducing
cleanup solvent VOC emissions, including
the use of low VOC cleanup solvents, if
the owner or operator shows that the
emission reduction is significant and this
method is approved by the director.
Recordkeeping - for each lithographic
printing subject to this rule records should
be maintained on the quantity of cleanup
solvents used on a monthly basis.
B-17
-------
TABLE B-l. (continued)
State
Cleanup solvent
specific regs?
What is regulated?
Specific requirements
Ohio, Dayton
Yea
Organic material emissions
from activities using
photochemically reactive
materials. Cleanup activities
are specifically included.
Quantity is restricted as:
1) 6.8 kg (15 Ib) of organic compounds
per day and 1.4 kg/hr (3 Ib/hour)
from all operations including cleanup
activities from any article, machine,
equipment, or other contrivance in
which substances which contain liquid
organic materials, come into contact
with a flame or are baked, heat-
cured, or polymerized, in the
presence of oxygen, unless said
discharge has been reduced by 85%.
These limits also apply to non-
photochemically reactive materials,
including cleanup for sources which
include a continuously moving sheet,
web, strip, or wire which is subjected
to any of the processes or any
combination of processes as described
above.
(2) 18.1 kg/day (40 Ib/day); 3.6 kg/hr
(8 Ib/hr) of organic compounds are
limits for emissions, including
cleanup, under conditions not
described in (1) for employing,
evaporating, or drying any
photochemically reactive material or
substance containing photochemically
reactive materials, unless said
discharge is reduced by at least 85%.
These limits apply to any combination
of processes as a continuously moving
sheet, web, strip, or wire as described
in (1) and (2).
There are no recordkecping requirements.
B-18
-------
TABLE B-l. (continued)
State
Oklahoma, Tulsa
City/County
Pennsylvania,
Allegheny County
Pennsylvania,
Philadelphia
Pennsylvania, State
South Carolina,
State
Tennessee,
Memphis & Shelby
County
Tennessee,
Metropolitan
Tennessee, State
Vermont, State
Virginia, State
Washington,
Puget Sound
Cleanup solvent
specific regs?
No
Yes
No
No
No
No
Yes
No
No
No
No
What is regulated?
Emissions of solvents used
for cleanup and purging of
surface coating operations.
Cold cleaning, open top
vapor degreasing and
conveyorized degreasing are
regulated.
Solvent metal cleaning.
Miscellaneous metal parts
and products. Special
provisions for new VOC
sources and modifications.
Conveyorized degreasing,
open top vapor degreasing
and cold cleaning are
regulated.
Specific requirements
Restrict emissions from surface coating
operations to < 1.4 kg/hr (3 Ib/hr) or
7 kg/day (15 Ib/day). Require daily
records of solvent quantity, composition
and density, and operating parameters.
Record nature, specific sources, and total
monthly VOC emissions, including
cleanup solvent.
Require good work practices, the use of
solvents that will result in the lowest VOC
emissions, and recprdkeeping of daily and
annual solvent use rates.
NA
B-19
-------
TABLE B-l. (continued)
State
Cleanup solvent
specific regs?
What is regulated?
Specific requirements
Wisconsin, State
Yes
Organic compound
emissions from activities
using organic compounds,
solvents, or mixtures.
Cleanup solvents are
specifically included.
Cleaning related to cured
and air dried coating
operations of miscellaneous
metal parts and products is
regulated.
Cold cleaning, open top
vapor degreasing,
conveyorized vapor
degreasing, and
conveyorized nonvapor
degreasing are regulated.
Use of good operating procedures with
solvents used in cleanup operations.
VOC emissions from solvent washings
will be considered in the emission
limitations set for cured and air dried
coatings unless the used wash solvent is
collected in containers that prevent
evaporation.
Reporting required for facilities with air
emissions of £0.23 Mg/d (0.23 ton/day)
or 45 Mg/yr (50 ton/yr) of any one or
more primary air contaminants. Daily
records for ink, coating, thinning and
cleanup solvents contain at minimum daily
usage and VOC content of each material.
NA = Not answered
aNo regulations provided - deferred to South Coast and Bay Area
B-20
-------
TABLE B-2.
CURRENT PRACTICE
Agency
Alabama, Jefferson County
Alabama, Huntsville
Alabama, State
Arizona, State
Arkansas, State
Ho* air permits include cleaning
Aggregate
w/other
sources
/
/
/
/
/
Considered
separately
/
/
/
Not considered
VOC Definition used*
EPA
EPA
EPA
Previous EPA
(plus methylene
chloride)
EPA
" Aspects of cleaning
operations checked during
inspection
VOC storage areas
VOC handling
methods
Presence of open
containers
Spill cleanup methods
Thinning solvents
Equipment cleanup
methods
* Daily records of
solvent usage
Waste solvent
recovery method
Final disposal of waste
solvent
Process operations/
procedure
Waste stream
characteristics
Storage/containment of
solvent
NA
Record of solvent
usage
VOC quantity emitted,
etc.
Record of solvent
usage
Plans for future cleaning
solvent regulations
None
Automotive refinishing
and restoration rule is in
developmental stage
None
Permitting
requirement for
solvent cleaning
Standards of perfor-
mance for solvent
cleaning
None
W
to
-------
TABLE B-2. (continued)
Agency
California, Bay Area
California, State
California, Lasson County
California, Ventura County
Colorado, State
How air permits include cleaning
Aggregate
w/other
sources
/
NA
/
/
Considered
separately
/
NA
Mot considered
NA
/
-
VOC Definition useda
EPA
(plus ethane)
EPA
No specific definition
EPA
Previous EPA (are
adding additional
compounds per EPA)
Aspects of cleaning
operations checked during
inspection
Look for uncovered
rags or paper
Open solvent
containers
Cleaning method for
spray equipment
Record of solvent
usage
Solvent storage
methods
Amount and type of
solvent
Visually inspect
application equipment
Methods of cleanup
Housekeeping
techniques
None
Record of solvent
usage
Proper storage/
disposal
VOC (g/L) or vapor
pressure limit
Permit limits (g/L,
type of solvents)
Records of solvent
usage
Compliance with rules
Plans for future cleaning
solvent regulations
Planning to set
volatility and VOC
limits for cleanup
solvents with
"Substitute Solvents
Used for Surface
Preparation/Cleanup
of Coatings"
Guidance document
is being developed
Possible
1/93 general rule to
cover all cleanup solvent
use not currently
addressed
None
at
to
10
-------
TABLE B-2. (continued)
Agency , , ,
Colorado, Denver
City/County
Florida, Jacksonville
Georgia, State
Indiana, Evansville
Indiana, State
[owa, State
How air permits include cleaning
Aggregate
w/otner
-. sources
NA
/
/
/
Considered
separately
NA
/
(if specific
cleanup
equipment is
used)
Not considered
. NA
/
VOC Definition used*
NA
Previous EPA
EPA
362 IAC
Previous EPA
EPA
Aspects of cleaning
operations checked during
inspection : :
Inventory records for
solvent purchased
Waste documentation
such as manifests and
recycling records
Housekeeping
procedures for
storage, use, and
disposal of solvents
and associated
materials
Type of solvents
Frequency of usage
Duration of usage
Quantity
Mechanism of
application
Controls
MSDS
Records of solvent
usage
Physical evidence of
usage
Solvent usage
Records of amounts
used
Area where solvents
are used
Equipment used for
cleanup
Compliance with
permit conditions
'';?.;/: "A ':;;.*:;
Plans for future cleaning
'_ v's0Weqt:r^|!a%fS?:-:;l
NA
None
None
NA
None
None
n
-------
TABLE B-2. (continued)
Agency
Iowa,
Polk County
Kansas, State
Kentucky, State
Louisiana, State
Maine, State
Maryland, Baltimore
Michigan, Wayne County
Minnesota, State
Missouri, State
Montana, State
How air pwittits include cleaning
Aggregate
w/other
sources^
/
/
/
/
/
(depends on
size and
type of
source)
S
Considered
separately
/
/
(depends on
size and type
of source)
/
(inconsistent)
/
Not considered
/
/
(depends on
size and type
of source)
/
(inconsistent)
VOC Definition useda
EPA
Previous EPA
EPA
Previous EPA
NA
Previous EPA
(currently undergoing
revision)
NA
Previous EPA
EPA
Aspects Q{ cleaning
operations'checked during
inspection
Recordkeeping report
Storage
Usage
Records
Records of raw
material usage
Records of solvent
usage
Waste solvent disposal
records
Records of solvent
usage
None
Look at all VOC's
used at facility
NA
Permit requirements
Records of solvent
usage
Solvent recordkeeping
Very cursory review
Plans for future cleaning
solvent regulations
None
NA
None
None
Solvent Metal
Cleaning regulations
will be adopted
Nov. 15, 1992
None
Only if State adopts new
regulations.
NA
None
None
-------
TABLE B-2. (continued)
Agency^ -
Nebraska, State
Nevada, Washoe County
North Carolina, Buncombe
County
North Carolina, State
North Carolina,
Forsyth County
Ohio, Dayton
Oklahoma, Tulsa City/
Couaty
Pennsylvania, Allegheny
County
Pennsylvania, Philadelphia
Pennsylvania, State
How air permits include cleaning
Aggregate
W/othet
. sources '
/
/
/
/
/
/
/
/
/
Considered
separately
/
/
(when a facility
does
inventories by
material
balance)
Not considered
/
(source
dependent)
VOC Definition used*
NA
vapor pressure
definition of 78 mm Hg
(<1.51b/in2)
Rule 66 and NC Toxics
State
EPA
Previous EPA
EPA and vapor
pressure definition
EPA
EPA
EPA
Aspects of cleaning
operations checked during
inspection
Cleaning operations are
not generally inspected
Solvent records
MSDS
Condition of
equipment
Records - use material
balance
NA
* Records of solvent
usage
Review facility
records
Work practices
Suggestions for
minimizing emissions
Recommend solvent
substitutions
Check annual
Emissions Inventory
Maintenance records
Applicable equipment
Record of solvent
usage
Records of solvent
purchase and usage
Records to determine
compliance w/ permit
Operating practices/
good housekeeping
Plans for future cleaning
solvent regulations
None
None
None
None
NA
None
None
NA
None
NA
to
I
ro
ui
-------
TABLE B-2. (continued)
Agency
South Carolina, State
Tennessee, Metropolitan
Tennessee, Memphis and
Shelby County
Tennessee, State
Vermont, State
Virginia, State
Washington, Puget Sound
s
How air permits include cleaning
Aggregate
w/other
- sources
/
/
/
/
/
/
[depends on
source size)
Considered
separately
/
/
/
/
/
(depends on
source size)
Not considered
/
VOC Definition used*
EPA
EPA
EPA
EPA
Vapor pressure
definition (are
proposing EPA
definition)
EPA
EPA
Aspects of cleaning
operations checked during
inspection
. NA
Look for good work
practice in use and
storage
Reports of annual
emissions including
cleanup losses
Records of solvent
usage
Records of solvent
usage
None
Check material
balance and other
records
Lids on VOC
containers
Spray equipment
cleaning method
Plans for future cleaning
solvent regulations
NA
None
None
None
None
NA
Wood finishing
regulations in
preliminary
development
Marine surface
coating regulations in
preliminary
development
w
-------
TABLE B-2. (continued)
Agency , > ' =
Wisconsin, State
How air permits include cleaning
Aggregate
w/other
sources
/
(coating and
printing)
Considered
separately
/
Not considered
VOC Definition used*
Previous EPA
Aspects of cleaning
operations checked during
inspection
Solvent containers
Dirty rags
Storage
Solvent reclamation
Plans for future cleaning
solvent regulations '
None
NA = Not answered.
aEPA:State uses current EPA definition of VOC from PR Vol.57 No. 22 February 3, 1992. Previous EPA:State defines VOC with EPA definition in
PR Vol. 56 No. 52 March 18, 1990.
w
to
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TABLE B-3.
SUGGESTIONS AND INFORMATION FOR GUIDANCE ON CLEANUP SOLVENT
EMISSION CONTROL TECHNIQUES
Agency >
Alabama, Jefferson
County
Alabama, Huntsville
Alabama, State
Arizona, State
Arkansas, State
Comments on approach
Address types of painting
equipment and paint used
None
None
None
Should not be too complex
to understand
Unit Operations cleaned at
inspected plants
Roll applicators
Flood and spray coalers
Conveyors for painted
products
Floor areas
Surface preparation
Spray painting equipment
and spray booths
Press cleaning
Distillation columns
Tanks
Spray booths
Printing machines
Parts cleaners
Process equipment (molds,
containers, etc.)
Individual parts cleaning
Fiberglass boat manufacturer
Available emission control case
study information
None
None
None
Spray painting operation
Boat manufacturing
Other into^iiation awj; \fjpC .
. reduction ideas :
Replace cleanup solvents
with nonorganic detergents
Use pyrolysis to clean parts
Maintain continuity with
fire safety and environ-
mental guidelines such as
NFPAa Guidelines for
spray booths and storage of
flammables
None
Substitution w/low VOC
solvents
Use vapor degreasing
Ration cleanup solvent to
workers
Lids on container
CD
I
NJ
00
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TABLE B-3. (continued)
- ,
Agency
California, Bay Area
California, State
California, Lassen
County
_
Comments on approach
Approach is practical
only if all "acceptable"
methods of cleaning are
identified and specified
Must identify current
cleaning methods to
develop emission
reduction factors
Could alternatively
identify cleaning methods
by source category and
identify acceptable
cleaning methods for
each category
Generalized guidance
may not be possible since
some sources have
specific needs-must
provide direction for
specific requirements of
these sources
Allow alternative
approaches to be
approved via director
N/A
Unit Operations cleaned at
inspected plants
Paint spray guns and
components
- Cold solvent parts cleaners
Printing presses
General wipe cleaning of
work areas, work benches,
spray booth filters
Coating applications,
manufacturing, and
degreasing
Surface preparation
General maintenance
Cleanup operations
N/A
Available emission control case
study information
Aerospace industry contact
provided
None
None
Other information and VQC
reduction ideas
Include methods to clean
auxiliary spray application
equipment such as supply and
distribution lines, large
pressure pots, and in-line
heating systems
None
N/A
a
(O
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TABLE B-3. (continued)
Agency
California, Ventura
County
Colorado, Slate
Colorado, Denver City/
County
Florida, Jacksonville
Georgia, State
ndiana, Evansville
' ' -::>'-X .':;' '
r.^o9uaenfa gin approach
Wide variety of sources
requires special
consideration
Alkaline cleaners not to
be used for cleaning
Aluminum
Water-based solvent rusts
some materials
Purity required in
electronics industry
Should limit all solvent to
200g/L(1.71b/gal)or
10 mm Hg (0.39 in. Hg)
at 20°C (68 °F)
w/specific exemptions
None
- Should state that TCE is
not an acceptable
substitute for VOC
solvents (Many small
industries have made this
change due to TCA's
exemption.)
None
None
NA
Unit Operations cleaned at
inspected plants
Oilfield equipment (well
heads)
Engines
Rocket engines
Spray guns
Coating application
equipment
Paint spray guns
Printing presses
Can coating lines
Coating line blades
NA
None
Printing press blanket wash
Paint spray booth
Aircraft stripping
NA
Available emission control case
study information
Boat manufacturing article
provided
None
NA
None
Provided 2 contacts for
automotive spray booth
cleaning data
NA
Other information and VOC
reduction ideas
Provided contacts on Technical
Review Group Solvents
Committee developing
BARCT/RACT* for "Surface
Preparation and Cleanup
Solvents"
NA
NA
None
Covers for tank cleaning
Non-VOC agents for floor
cleaning
NA
u>
O
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TABLE B-3. (continued)
< r '
Agency
Indiana, State
Iowa, State
[owa, Polk County
Kansas, State
Kentucky, State
,.
Comments on approach
Recordkeeping is
burdensome to both
company and -agency, not
easily verified, is easily
falsified, and not reliable
for compliance
Impose State or federal
tax on cleanup solvents
sold or manufactured as
incentive to reduce
usage. Then provide
information on how
sources can reduce
emissions
NA
Inclusion of fugitive
VOC's in permanent total
enclosure capture effi-
ciency calculations
motivates limiting usage
* Should address handling
and storage of solvents
and rags
Solvent should be
extracted from rags
before treating rags
Should not apply to
sources where the State
currently includes
cleanup as part of source
specific RACT or BACT
Unit Operations cleaned at
inspected plants
Distillation columns
Tanks
Spray booths
Printing machines
Parts cleaners
Surface preparation
Dip tanks
Doctor blades
Rolls
Printing presses
Chemical reactors
Plastic injection molds
Paint applicators
Available emission control case
study information
None
None
NA
None
None
Other information and VOC
reduction ideas
Should be simple and field
enforceable
Inspectors need to check
physical aspects
Solvent taxes may be best
way to reduce emissions
Records are not reliable
None
Avoid compliance costs of
VOC's by using aqueous-
based systems
MN and TX Air Control
Boards have done work
with solvent-laden rags
None
CD
CO
-------
TABLE B-3. (continued)
Agency
Louisiana, State
Maine, State
Maryland, Baltimore
Michigan, Wayne County
Minnesota, State
Missouri, State
Montana, State
Nebraska, State
Nevada, Washoe County
Comments on approach
None
None
Regulations will cover
certain generic
operations. Industry may
have difficulty
determining whether their
cleaning activity is
regulated
Possible incompatibility
of wipe solvent and
surface coating system in
automobile assembly
None
None
None
None
N/A
Unit Operations cleaned at
.. inspected plants
Assembly line operations
Aircraft maintenance
Auto/truck maintenance
None
Spray booths
Printing presses
Paint shipping containers
Spray booths
Vehicle wiping prior to
painting
N/A
Printing facilities
Paint spray booths
Particleboard
finishing/printing line
Safety Kleen solvent
stations
Hand applications
Dip tanks
Printing operations
Spray booths
Mixing operations
* Packaging operations
Plastics production
Available emission control c4Se
study information
None
None
None
NA
None
None
None
Example of add-on control
(thermal incinerator)
Add-on control example
Distillation recovery
example
Qthw information and VQC
reduction ideas
None
New source categories are
low priority compared with
other CAAA requirements
None
NA
NA
None
NA
NA
None
ffl
W
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TABLE B-3. (continued)
Agency
North Carolina,
Buncombe County
North Carolina, State
North Carolina, Forsyth
County
Ohio, Regional
Oklahoma, Tulsa City/
County
Comments on approach
None
Reasonable cutoff level to
exempt small users
None
None
Should be directed at
specific solvents
Recordkeeping require-
ments and methods of
controlling emissions
should be enforced by
State
De minimus limits for
emissions
Define economic impact
for affected industries
Industry review prior to
publication
Unit Operations cleaned at
inspected plants
None
NA
Roller and blanket wash
Paint spray nozzle
Printing press cylinders
Parts washers
Grates in painting
operations
Spray booths
Surface preparation for
adhesive application.
None
Available fttnissioti control case
study information
None
Provided contact at agency
None
NA
None
Ottutf rofonnatioti and VOC
reduction ideas
None
None
None
Small facilities do not
account for collected
solvent, so that emissions
appear to be usage
Public relations incentives
where facilities that reduce
emissions by some percent-
age are listed as "Clean
Facilities"
De minimus limits based
on annual emissions rather
than single cleaning event
emissions
Establish hourly limits to
prevent exposure
o
u>
Ul
-------
TABLE B-3. (continued)
Agency
Pennsylvania, Allegheny
County
Pennsylvania,
Philadelphia
Pennsylvania, State
South Carolina, State
Tennessee, Metropolitan
Tennessee, Memphis and
Shelby County
Tennessee, State
Comments on approach
Specify industry or
source category since
broad regulations on
equipment enclosure,
solvent substitution, and
work practice impacts a
large number of
industries
None
Generic requirements are
better than none.
None
Stress solvent
substitution
Stress work practice
Most of the agency's
cleanup solvent sources
are small businesses -
Equipment changes
present financial burden
for these firms
Solvent substitution and
work practice are more
useful
None
Unit Operations cleaned at
inspected plants
Printing
Spray booths
Coil coaters
Paper coaters
Mixing tanks
Automobile repairs
Laboratories
Printing press
Coaters
Parts cleaners
NA
Fiberglass and paint spray
gun
Printing presses
Painting equipment
Paint manufacturing
Boat manufacturing
Misc. boat manufacturing
Printing presses
Automobile/truck servicing
shops
Spray booth
Paper making machines
Wipe operations
\
None
Available emission control case
"' study information
None
Provided contact in
shipbuilding industry
NA
NA
None
None
None
Other information and VQC
reduction ideas
Use of low VOC solvents
where feasible
Better housekeeping
Require solvent collection
and recovery in extreme
cases
Require recordkeeping
Charge $25/ton for
unrecovered solvents
None
NA
NA
None
None
None
W
-------
TABLE B-3. (continued)
As«*°y : I
Vermont, State
Virginia, State
Comments on approach
NA
NA
Unit Operations cleaned at
inspected plants " '
Printers
Dip cleaning of plating
materials
Coating equipment
Spray booths
Printing machines
Parts cleaners
Available emission control ease
, study information >
NA
None
Other information and VOC
reduction ideas , ..
NA
None
CD
to
U1
-------
TABLE B-3. (continued)
-
Agency
Washington, Puget Sound
Wisconsin, State
-
Comments on approach
Military and commercial
aircraft specifications
limit solvent choices
list specific source
categories
Include problems
encountered and specific
successes achieved in
these categories
Case study information
is helpful
None
Unit Operations cleaned at
inspected plants
Spray guns
Spray booth
Foam manufacturing
Paint and ink manufacturing
Mixing vats
None
Available emission control case
study information
- Will provide aerospace and
boatbuilding contacts
Provided contact for WA
department which assists
facilities in reducing
hazardous waste
None
Other information and VQC
reduction ideas
Emphasize case studies
Work with industries
None
w
i
aNational Fire Protection Association.
Best available retrofit control technology/reasonably available control technology.
°Best available control technology.
-------
B.3 REFERENCES FOR APPENDIX B
1. Jefferson County Department of Health. Section 8.11.12.
2. City of Huntsville, Alabama. Air Pollution Control Rules
and Regulations. Department of Natural Resources and
Environmental Management. Ch.8, 8.11.12(a)(3).
April 1992.
3. Arizona Department of Environmental Quality. Arizona
Administrative Code, Title 18, Chapter 2, R18-2-530.
4. Bay Area Air Quality Management District. Regulation 8:
Organic Compounds. 8-1-300, -320, -321, -322. May 1988.
5. South Coast Air Quality Management District. Staff Report
for Rule 1171: Solvent Cleaning Operations. SCAQMD
No. 910626MG. June 1991.
6. Ventura County Air Pollution Control District. Summary of
Cleaning Solvent Regulations.
7. Air Pollution Control Section. Kansas Department of Health
and Environment, Proposed New Regulation No. 28-19-76.
June 1991.
8. Air Pollution Control Division. Wayne County Health
Department. Michigan Department of Natural Resources.
Rule 630.
9. Air Conservation Commission. Code of State Regulations.
Department of Natural Resources. 10 CSR 10-2.340,
10-2.290. March 1992.
10. Regional Air Pollution Control Agency. Regulation
NO. 3745-21-07{G)4.
11. Bureau of Air Pollution Control. Allegheny County Health
Department. Section 505.
12. Metropolitan Health Department. Pollution Control
Division. Sections 7-i4(c)(6), 7-l6(f), and 7-23.
13. Wisconsin Department of Natural Resources.
Section NR 419.03(2), NR 101.21(4), NR 101.22(3),
NR 422.15(8), Wisconsin Administrative Code.
B-37
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APPENDIX C.
-------
APPENDIX C.
C.I UNIT OPERATION APPROACH
Cleaning with solvents in an industrial setting may be
perceived on a unit-operation basis.1"4 The conventional unit
operation, a term common to the chemical engineering discipline,
is an industrial operation classified or grouped according to its
function in an operating environment. Unit operations vary
considerably among industries. Examples include items of
traditional production equipment such as a distillation column, a
paint mixing vessel (tank), or a printing machine. Other less
traditional examples could be defined as areas in which
manufactured parts are handled or cleaned, a spray booth, or a
parts cleaner.
A manufactured product may require cleaning to prepare it
for a subsequent manufacturing step. An example is to remove
contaminants from a primed car body prior to topcoating. A high
standard of cleanliness is required both to ensure proper
adhesion of the coating and to remove any contaminant that would
signal its presence through the paint, resulting in a blemish or
unevenness.
In some cases, unit operations are production equipment
that must be cleaned to avoid contamination between different
batches of material manufactured using the same equipment.
Cleaning mixing vessels between batches of different adhesive
compounds is an example. Another is solvent purging of spray
guns and associated hoses between color changes. Cleaning
production equipment or work areas is also done to maintain
equipment and provide clean working environments for employees.
C-l
-------
Data were solicited from the focus industries based on a
material balance around a unit operation system (UOS). For
purposes of material balance calculations, the concept of the
unit operation "system" extends the boundaries of the
conventional "unit operation". The UOS is defined as the
ensemble around which a material balance for cleaning can be
performed. The boundaries of a UOS should be selected to include
all possible points/sources leading to evaporative emission
losses associated with cleaning a specific unit operation,
including losses during dispensing the solvent, spilling virgin
and used solvent, handling residual solvent in cleaning
applicators, etc. Emissions from waste management
(e.g., recycling or subsequent treatment) are not to be included
within a UOS.
A material balance is a mathematical statement that
expresses the law of conservation of mass (i.e., at equilibrium,
the mass that flows into a process or UOS equals the mass out).
It can be used to calculate the quantity or composition of one
stream when all others flowing in and out of the UOS are known.
For this study, material balances are written for the
VOC-containing solvents used within a UOS. In many cases, the
unknown "stream" is the cumulative emissions from within the UOS.
The material balance can quantify this total.
An example of a unit operation system for a "wiping-
cleaning" activity is provided in Figure C-l. Whereas a
conventional material balance around this unit operation might
attempt to limit an evaluation of Streams A and B (see small box
within Figure C-l), the "system" concept is more pragmatic. It
incorporates any inefficiencies (additional evaporative losses)
that precede or follow the unit operation but would not have
happened were it not for the activity at the unit operation. The
"system" encompasses the virgin solvent container, the cleaning
applicators (rags), the unit operation being cleaned, the spent
solvent remaining in the virgin solvent container (dirtied from
dipping the rag in the container), and the container for used
cleaning applicators. Note that the UOS encompasses the entire
C-2
-------
EVAPORATIVE
LOSS, V!
EVAPORATIVE
LOSS, V2
EVAPORATIVE
LOSS, V3
SYSTEM
BOUNDARY
SOLVENT
INPUT,
EVAPORATIVE
LOSS, V4
USED SOLVENT OUTPUT, S2
WITH X1 WEIGHT FRACTION
CONTAMINANTS
NET SOLVENT = S2(1-x2)
SOLVENT IN RAGS, S4
NET SOLVENT = S4(1-X4)
USED SOLVENT IN RAG CONTAINER, S3
WITH x3 WEIGHT FRACTION
CONTAMINANTS
NET SOLVENT = 83 (1-x3)
Figure C-l. Example unit operation system (uncontrolled)
C-3
-------
path of the solvent from the time it leaves a controlled
environment (closed vessel) until it is physically removed
(e.g., taken off site for disposal or removed from storage for
reuse onsite) . The following equation represents the VOC
material balance for the UOS in Figure C-l:
V-L + V2 + V3 + V4 = S^i - S2f2(l-X2) - S3f3(l-X3) - S4f4(l-X4)
where :
vl' V2» V3' and V4 = voc
Slf S2, S3, and S4 = Solvent streams, Ib/yr;
fl» f2' f3' and f4 = VOC wei9nt fraction in solvent,
Ib voc/lb solvent; and
xlf x2, x3 and x4 = Contaminant weight fraction in spent
solvent, Ib contaminant /Ib waste.
Completion of the material balance around a UOS requires
measurement (or estimates) of all input and output VOC-based
liquid solvent streams. The difference between these streams,
(after accounting for the contaminants and the .VOC content of the
solvent) , may be assumed to have evaporated as solvent emissions.
In the example of Figure C-l, there is one input stream, slf into
the UOS. If the solvent is not 100 percent VOC, the total
solvent input must be multiplied by the solvent's VOC weight
fraction.
Material balances around a UOS should be applied with care
to obtain precise and accurate emission estimates. In general,
the more complex the UOS the more difficult it is to obtain
precise answers. Simpler UOS's will have fewer, more easily
measured input and output streams. Another factor that may
affect the precision of the emission estimates is the time frame
over which data are collected and averaged. Longer term tests,
generally have more precision. In the example of Figure C-l, an
annual basis is used.
There are seven output streams in the example of Figure C-l;
three are solvent and four are gaseous. The three output solvent
C-4
-------
streams, S2, S3, and S4, represent collection of liquids from the
system. The 82 stream is the amount of solvent remaining in the
solvent container; S3 and S4 are, respectively, any solvent
accumulated in the container that houses used cleaning
applicators and the solvent remaining in the cleaning
applicators. In some cases, S3 and S4 may be zero because the
container permits it all to evaporate before it can be reclaimed,
recycled, or disposed.
These solvent streams likely contain contaminants, a
consequence of cleaning. Contaminant removed from a cleaning
applicator may be introduced into the solvent container if the
applicator (rag) is dipped. Contaminant levels in the output
streams include the weight fractions in the spent solvent (x1),
in the applicators (x2), in any container used for the soiled .
applicators (x3), and contaminants in cleaning applicators (x4).
Knowledge of these contaminant levels may be necessary to
determine the mass of solvent in the waste stream. This could be
an essential interim step to accurately determine the total
VOC-based solvent that evaporated during cleaning. If
compensation is not made for the contaminant level, estimates of
emission levels will be biased low. The output solvent streams
would be assumed to be all solvent, thereby inflating the
discharge value.
In this UOS, contamination of S2 can be eliminated if
solvent is dispensed onto the applicator, rather than dipping the
applicator into the solvent. That is, the contaminant level in
the virgin solvent container will remain zero. For UOS's that
include flushing, purging, spraying, or dipping, contamination of
the solvent is unavoidable because it occurs by direct contact of
solvent with the contaminant on the surface of the unit
operation.
The VOC content of the liquid fraction of the spent solvent
may need to be determined in cases where input solvents consist
of mixtures of VOC's and non-VOC's. In cases where solvent
volatility is low (where evaporation losses are not significant),
a practical approximation is to assume that the VOC weight
C-5
-------
fraction in each spent solvent stream (after correcting for
contaminant) is the same as that in the input solvent (i.e., f^
f2, f3, and f4 are equal).
The gaseous output streams from the cleaning shown in
Figure C-l include evaporative losses from the solvent container,
the cleaning applicators, the surface being cleaned, and the
spent solvent container. Other emission streams may exist, not
shown here, such as evaporation from virgin and spent solvent
storage vessels. These should also be attributed to the UOS.
Another factor to consider in some UOS's is process solvent
that is collected with spent cleaning solvent. For example,
paint in a spray gun contains thinning solvent, a process-derived
VOC. Spent solvent collected from cleaning the spray gun
includes both process and cleaning solvent. Therefore, a
rigorous material balance would require correction for the amount
of process solvent associated with the paint in the gun. This
amount may be estimated based on knowledge of the solids
(contaminant) content in the spent solvent and the solids
(nonvolatile matter) content in the purchased paint. See
Appendix G for additional details.
In response to EPA's information request, companies
identified the unit operations that they clean and defined UOS's
for each. They then performed a material balance to calculate
the emission rate for each UOS. The variety of systems submitted
by the surveyed plants in the focus industries were found to be
of nine distinctively different types of UOS's (although there
may be subcategories within some). The nine, listed and
explained below are believed to be representative of most solvent
cleaning performed by all industry:
1. Spray gun cleaning includes spray guns, attached paint
lines, and any other gun equipment used in applying a coating;
2. Spray booth cleaning includes all interior surfaces of
booths and all equipment within the booth such as conveyors,
robots, etc.;
3. Large manufactured components cleaning (i.e., the
cleaning of large parts as a step in the manufacture process)
C-6
-------
includes large manufactured products, such as automobile bodies,
furniture sheet metal, etc.;
4. Equipment cleaning includes all production equipment
that may be cleaned in place (not moved to a cleaning area) to
prevent cross-contamination or merely for maintenance purposes.
Examples are punch presses, electrical contacts on a major piece
of equipment, pump parts, packaging equipment, rollers, ink pans,
carts, press frames, and table tops;
5. Floor cleaning includes floors in all production areas
of a facility;
6. Line cleaning includes lines that transport raw material
(e.g., paint, resin) and that are cleaned separately from tanks,
spray guns, and other process equipment. In some cases a small
tank may be part of the system;
7. Parts cleaning includes miscellaneous items that might
be moved to dip into a container of solvent. Examples of parts
include applicator tips, brushes, machine parts, pumps, circuit
boards, truck parts, engine blocks, gauges, cutoff steel/machined
parts, tool dies, motors and assemblies, screws, oil guns, welded
parts, bearings, and filters;
8. Tank cleaning includes mixing pots, process vessels, and
tanks. In some instances, tank lines are cleaned in conjunction
with the tanks and would be considered part of. the system; and
9. Small manufactured components cleaning (i.e., the
cleaning of small parts as a step in the manufacture process)
includes small manufactured products such as glass windows,
engine components, subassemblies, sheet metal panels, molded
parts, electrical contacts, steel and copper components,
tin/silver-plated terminals, plastic parts, upholstered parts,
circuit breaker cases, switch covers, and threads and bolts.
These nine types of UOS's provide a framework for describing
and understanding cleaning. They were selected based on
differences in the level of cleanliness required, method of
cleaning, type of contaminants removed, size and use of the item
being cleaned, and types of solvents used. In some cases it also
may be possible to define subcategories within a given UOS
C-7
-------
category; for example, several spray gun cleaning subcategories
are discussed in Chapter 4.
The large and small manufactured components and equipment
UOS's share a number of similarities. They were developed as
three separate categories because of the following differences.
First, the data from surveyed plants revealed different reasons
for cleaning. Large components were typically cleaned in
preparation for painting. Smaller components tended to be more
complex shapes and were cleaned as part of a product-assembly
process. Equipment was cleaned for maintenance and to provide a
safe workplace.
Second, although the data from the surveyed plants did not
show a difference, it was initially believed that equipment would
more likely be cleaned to remove oil, grease, and dirt, whereas
manufactured components would more likely be cleaned to remove
glue, wax, markings, and other production-related contaminants.
A specific size cutoff between large and small manufactured
components was not established, but it was roughly based on
whether the component could be moved by an individual.
Tank and line UOS's are similar in that both may consist of
a tank and process lines. The tank UOS, however, is perceived as
having only a short amount of piping that is cleaned with the
tank so that the majority of surface area cleaned is in the tank.
Conversely, the line UOS consists of an extensive piping network
that may also include a tank; the majority of the surface area
cleaned is in the lines.
C.2 UNIT OPERATION SYSTEM DESCRIPTIONS
Figures C-2 through C-10 and their accompanying narratives
provide detailed information for the nine UOS's developed from
responses to the Agency's request. The diagrams provide a
pictorial presentation of the components and boundaries of each
UOS. The narratives each explain industrial application,
frequency and purpose of cleaning, emission points, and common
solvents used within the system.
C-8
-------
Equipment Cleaning Unit Operation System
Equipment (rollers, pumps, coaters, paint buckets, machines,
conveyors, screw bowl machines, bearings, packaging machines,
punch press, electrical contacts, ink templates, etc.) is
primarily cleaned with some type of applicator and solvent. Due
to the varying nature of equipment, the solvent can be applied in
many different ways. However, an applicator is commonly used to
spread the solvent and wipe the surface clean. The applicator is
usually dipped into the solvent, applied to the equipment, wrung,
and stored in barrels before being sent offsite. The type of
contaminants removed are gelatin, small particles, ink, dirt,
grease, paint, and wax. Emission sources include the solvent
container, the soaked applicator, the equipment while being
cleaned, and the final storage container, where the applicator
may be air-dried. Ethanol, isopropyl alcohol (IPA), butyl
acetate, propane, isobutane, butane, cyclohexane, naphthalene,
toluene, acetone, xylene, and ethyl acetate are frequently used
solvents for equipment cleaning, as seen in the focus industries.
Any equipment parts that are cleaned in a dedicated cleaning
vessel are classified in the parts UOS.
USED APPLICATORS
CONTAINER
APPLICATOR
BEING WRUNG
SOLVENT CONTAINER
EQUIPMENT
L
j
SOLVENT FLOW
EMISSIONS
Figure C-2. Equipment cleaning unit operation system.
C-9
-------
Floor Cleaning Unit Operation System
The floor cleaning UOS consists of a solvent container, an
applicator (e.g., mop, rag), a floor surface, a used applicator
storage container, and a dirty solvent collection container.
Routine floor cleaning is conducted to remove paint, grease, oil,
and grime. The frequency of cleaning ranges from once a week to
five times a day. Emission points include the open solvent
container, the applicator while in use, the floor after solvent
is applied, the used applicator storage container, and the
solvent collection container. Typical solvents used to clean
floors include acetone, methyl ethyl ketone (MEK), and ethyl
acetate. ;
USED
APPLICATORS
.CONTAINER
USED LEFTO
SOLVENT CONTAI
DIRTY SOLVENT
COLLECTION CONTAI
IER
«> SOLVENT FLOW
-REMISSIONS
Figure C-3. Floor cleaning unit operation system.
C-10
-------
Large Manufactured Components Unit Operation System
Large manufactured components (e.g., auto bodies, furniture
components, and sheet metal prior to stamping processes) are
cleaned during manufacture using a solvent container and an
applicator (brush or paper towel). These components are cleaned
to prepare the surface for future treatment by removing grease,
oil, grime, dye, polyurethane and polysulfide sealants, and
adhesives. Emission sources are the solvent container, the
applicator, the component, and the spent applicator. Commonly
used solvents include xylene, IPA, naphthalene, MBK, and acetone.
USED APPLICATORS
CONTAINER F
LARQE MANUFACTURING COMPONENT
SOLVENT FLOW
EMISSIONS
Figure .C-4. Large manufactured components unit operation system.
C-ll
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Small Manufactured Components Unit Operation System
Small manufactured components (e.g., contacts, switches,
machined parts, and circuit breaker cases) are cleaned during
manufacture by applying the solvent from a solvent container onto
an applicator and wiping the unit. Small components have
contaminants similar to the large manufacturing components.
Emission points include the solvent container, the applicator,
the manufacturing component, and the used applicator storage
container. Acetone, xylene, toluene, ethanol, IPA, and butyl
acetate are commonly used to clean small manufactured components.
APPLICATOR
1
USED APPLICATORS
CONTAINER
SOLVENT
CONTAINER
SMALL MANUFACTURING
COMPONENT
_J
SOLVENT FLOW
EMISSIONS
Figure C-5. Small manufactured components unit operation system.
C-12
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Line Cleaning Unit operation System
The lines unit operation consists of a line alone or an
extensive network of piping with a tank. Lines and associated
tanks are cleaned to remove contaminants, typically paint or
other coatings, between batches or for maintenance. The solvent
is flushed through the tank and lines and sent to the spent
solvent container, and the spent solvent is then disposed of or
recycled. Emission points are the solvent container, tank, line
fittings, and spent solvent container. Xylene, butyl acetate,
ethyl benzene, toluene, tetrahydrofuran, cyclohexanone, and MEK
are often used to perform this task.
SOLVENT
CONTAINER
SPENT
SOLVENT
CONTAINER
SOLVENT FLOW
EMISSIONS
Figure C-6. Line cleaning unit operation system.
C-13
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Spray Booth Cleaning Unit Operation System
The solvent is typically applied by spraying or wiping the
surfaces within the spray booth (e.g., spray booth walls,
conveyors, floor, and grating). After application, the solvent
is wiped with an applicator (brush or rag). The applicator is
usually stored after use in a plastic sealed drum and sent
offsite. Emission sources are the solvent containers, the
applicator, surfaces in the booth, and the used applicator
container. Many different solvents are used for this operation,
and the solvent choice depends on the industry. Common choices
include mineral spirits, toluene, acetone, xylene, IPA, ethyl
glycol butyl ether, and diisopropylene glycol monoethyl ether.
USED APPLICATORS
CONTAINER
SOLVENT FLOW
EMISSIONS
Figure C-7. Spray booth cleaning unit operation system.
C-14
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Spray Gun Cleaning Unit Operation System
The spray gun cleaning unit operation system consists of a
solvent container, a solvent transfer container, the spray gun,
attached lines that are cleaned with the gun, possibly a paint
collection vat, and a spent solvent collection container. Spray
guns are typically used by industries that paint as part of their
manufacturing process. The frequency of cleanings is based on
the industry's need to change paints. Every time a new color or
type of paint is used, the gun has to be cleaned. Some
industries use spray guns to apply oil as well. In some
instances, the gun is purged into a sink in or near the spray
booth and the dirty solvent is drained to the spent solvent
container. Emission points include the solvent container, the
transfer container, the gun, the spent solvent transfer unit, and
the spent solvent storage containers. Xylene, MEK, lacquer
thinner, diethylene glycol monobutyl ether, acetone, acetic acid,
naphthalene, methyl benzene, ethyl benzene, butyl acetate, methyl
isobutyl ketone (MIBK), or methanol are frequently used solvents
for this operation, as seen at plants in the focus industries.
The diagram below shows manual cleaning in which all spent
solvent is discharged through the nozzle; the solvent that does
not evaporate in this process is collected. Different procedures
are used for cleaning automated spray equipment: solvent is
introduced directly into the paint line, and most of the used
solvent is drained from the base of the gun to a spent solvent
storage tank or recirculated to the feed tank. Only a short
burst through the gun tube and nozzle is discharged to the
atmosphere, and this discharge is allowed to evaporate.
SPENT SOLVENT
TRANSFER CONTAINER
USED SOLVENT
COLLECTION CONTAINER
PAINT COLLECTION
CONTAINER
fr SOLVENT PLOW
-* EMISSIONS
Figure C-8. Spray gun cleaning unit operation system.
C-15
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Tank Cleaning Unit Operation System
The tanks UOS consists of a tank or reactor vessel alone or
with a small amount of attached piping that is cleaned with the
tank. Solvent is poured into the tank, and the tank is wiped
with an abrasive tool (a brush). The spent solvent is generally
used to flush short chemical lines and is then disposed of.
Tanks are cleaned to remove residues, grease, and sludge bottoms.
The emission sources include the pouring operation, the used
brush or rag, and the solvent evaporating from the tank.
Commonly used solvents for tank cleaning by plants in the focus
industries include ethanol, MEK, acetic acid, naphthalene, ethyl
benzene, methyl benzene, MIBK, xylene, cyclohexanone,
tetrahydrofuran, toluene, and ethyl acetate.
In some cases, tanks are cleaned without manual scrubbing.
Tanks can also be cleaned either manually by spraying the
interior surfaces with the lid opened or automatically with the
tank lid closed. A spray arm is lowered into the tank, the tank
lid is closed, and solvent is sprayed on the interior tank
surfaces.
At some facilities, a combination of the above cleaning
methods is used.
USED APPLICATORS
CONTAINER
~\
SOLVENT
TRANSFER
CONTAINER
SPENT SOLVENT
STORAGE
CONTAINER
SOLVENT FLOW
EMISSIONS
Figure C-9. Tank cleaning unit operation system.
C-16
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Parts Cleaning Unit Operation System
There are many varied ways of cleaning parts. The most
common means of cleaning parts is to put them in a sink and spray
solvents from a spigot on the parts. The solvent then drains
back to a storage container to be reused later. Another method
of cleaning parts is to dip the parts into solvent contained in a
sink or bucket. The contaminants of interest are grime, grease,
paint, wax, ink, etc. In both methods, there are potential
emissions from the solvent application, the part, and the spent
solvent storage container. Parts commonly cleaned in this manner
include filters, tools, punch press dies, paint brushes, and
spray gun tips. Naphthalene, MEK, toluene, ethyl benzene,
xylene, IPA, kerosene, tetrahydrofuran, MIBK, cyclohexanone, and
ethyl acetate are often used to clean parts.
In some cases, a machine similar to a dishwasher is used.
The contaminated part is placed in the machine, the cover is
closed, spray nozzles introduce solvent into the machine, and the
dirty solvent is piped into a storage or waste tank. An air
pollution control device is often attached to the unit to control
air emissions.19 The entire operation is a closed loop. From
such equipment, emissions are greatly reduced.
SPENT SOLVENT
CONTAINER
SOLVENT FLOW
EMISSIONS
Figure C-10.
Parts cleaning unit operation system.
C-17
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C.3 REFERENCES FOR APPENDIX C
1. Serageldin, M. A. Information Requested from Manufacturers.
U. S. Environmental Protection Agency, Research Triangle
Park, NC. October 16, 1991.
2. Serageldin, M. A., J. C. Berry, and D. I. Salman. A Novel
Approach for Gathering Data on Solvent Cleaning. U. S.
Environmental Protection Agency. Research Triangle Park,
NC. Publication No. EPA/600/R-92/131. May 1992. 7 pp.
3. Memorandum from Serageldin, M.A. EPA/CPB, to Trenholm, A.,
MRI. September 30, 1992. List of definitions for the
Industrial Cleanup Solvent CTG.
4. Serageldin, M.A., "The Unit Operation System--A New Solvent
Management System." U. S. Environmental Protection Agency
APTI Course No. 582: Issues Related to VOC Control Systems
Teleconference Workshop. July 22-23, 1993 (North Carolina
State University, Environmental Program -IBS).
C-18
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APPENDIX D.
AMERICAN AUTOMOBILE MANUFACTURERS ASSOCIATION (AAMA) PROPOSAL
-------
Enclosure
Motor Vehicle Manufacturers Association
of the United States. Inc.
Thom»H.iu»a. October 2, 1992
President and Chtef Executive Officer
Mr. James C. Berry, Chief
Chemical Application Section
Chemicals and Petroleum Branch
Emission Standards Division
U.S. Environmental Protection Agency
Office of Air Quality Planning and Standards
Research Triangle Park, North Carolina 27711
Dear Mr. Berry:
This letter is a followup to our meeting on August 26, 1992 when we discussed an
Engineering Project Study related to the current Environmental Protection Agency (EPA)
effort to prepare a Cleanup Solvent Control Technology Guideline (CTG). The enclosed
proposal has been prepared along the lines discussed.
It is proposed that the enclosed study procedure be incorporated into the draft CTG.
The Motor Vehicle Manufacturers Association of the United States, Inc. (MVMA) is
proposing this study in lieu of detailed recordkeeping and reporting procedures under
consideration by EPA. Requiring detailed records for individual point sources (i.e., a
topcoat booth) on a routine basis would not be cost effective, and potentially would provide
inaccurate data. The added cost resulting from such inappropriate requirements for detailed
records is not justified and runs counter to one of the objectives of the Clean Air Act ~> to
promote the productive capacity of the Nation. The MVMA approach will identify
opportunities for potential recordkeeping control points unique to each plant and its
capabilities and will result in appropriate emission reductions.
As you know, our members are not in the business of performing CTG studies but
they do know a lot about cleanup solvents and how to best evaluate their usage in a
production envkQwent Please contact me with any questions or discussion points you may
have. We will be interested in learning of your reaction to this proposal.
Sincerely,
E. A. Praschan
Manager, Emissions & Control
Enclosure
7430 Second Avenue. Suite 300 Detroit. Michigan 48203
Tel. No. 313473-4311 Pax No. 313-873-5400
D-l
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A PROTECT STUDY PROPOSAL
ON
CLEANUP SOLVENT USE
IN
MOTOR VEHICLE MANUFACTURING ASSEMBLY OPERATIONS
For
A CONTROL TECHNOLOGY GUIDELINE (CFG)
The Enviroomeotal Protection Agency (EPA)
October 2, 1992
The Molar Vdride Mvm&ctmen Association of the Umttd Slate*, Inc.
7430 Second Avenue, Suite 300
Detroit, TUicJrfm 48202
D-2 ,
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A PROTECT STUDY PROPOSAL
ON
rr.P.f FffTP gQLVENT USE
IN
MOTOR VEHICLE MANUFACTURING ASSEMBLY OPERATIONS
This is an Engineering Project Study Proposal on Cleanup Solvent usage and control
in motor vehicle manufacturing assembly operations. It is intended that this study be
incorporated into the Control Technology Guideline (CTG) on Cleanup Solvent now being
addressed by the Environmental Protection Agency (EPA). The study could be performed
either by individual company and plant personnel or in cooperation with an outside
contractor.
The study would be done in lieu of detailed recordkeeping and reporting procedures
under consideration by EPA. The MVMA approach will identify potential recordkeeping
control points in addition to identifying appropriate emission reductions. Containing the
impact of inappropriate recordkeeping and reporting will help to balance two key Clean Air
Act goals - to protect and enhance air quality and to promote the Nation's productive
capacity.
ApplirahlHfr
The 1990 Clean Air Act (CAA) Amendments require that State Implementation Plans (StPs)
for certain ozone nonattainment areas be revised to require the implementation of Reasonably
Available Control Technology (RACT). EPA, in the Ffdflffll KfigiittfT notice 44 FR 53761
(September 17, 1979), defines RACT as: "the lowest emission limitation that a particular
source is capable of meeting by the application of control technology that is reasonably
available considering technological and economic feasibility." RACT is to be used to control
volatile organic compound (VOQ emissions from sources for which the EPA has already
published, or is required to publish a CTG.
A CTG for Cleanup Solvents is one of eleven CTG's that EPA must publish within three
years of enactment of the 1990 CAA Amendments, i.e., by November 15, 1993. It will
identify RACT for control of VOC emissions generated from cleaning solvents used in
manufacturing assembly operations. The CTG's are intended to provide State and local air
D-3
-------
pollution authorities with an information base for proceeding with their own analyses of
RACT to meet statutory requirements. The CTO's review current knowledge and data
concerning the technology and costs of various emission control techniques. Each CTG
contains a "presumptive norm" for RACT for a specific source category, based on EPA's
evaluation of the capabilities and problems general to that category. Where applicable, EPA
recommends that States adopt requirements consistent with the presumptive norm.
Consequently, it is appropriate that the draft CTG provide guidance on studies of cleanup
solvent operations in existing plants and that the studies identify those capabilities, problems,
concerns and any potential exemptions or de minimis levels considered appropriate for
cleanup solvent usage in RACT plants.
The study would identify sources and usage of cleanup solvent through a comprehensive
(suggest minimum of three months) review of purchase records, plant distribution sources,
identifiable cleanup operations, and recycling and waste disposal records where quantities are
justified. The study would also identify potential VOC usage reductions at each applicable
RACT plant
The study would not include non-manufacturing area cleanup such as cafeterias, restrooms,
office buildings, etc., nor would it include non-routine, "one time only type" maintenance
cleanup of manufacturing facilities and equipment. To prevent duplication, a source for
which there has been a RACT, BACT (best achievable control technology) or LAER (lowest
achievable emission rate) determination made within 18 months of the date of this proposed
study would be excluded from this new study. Likewise, where there has been, or will be, a
cleanup solvent case study involving an identical or similar operation that is transferrable,
that case study would not be repeated to fulfill the requirements of this study for that
operation. Of course, similarities and differences would be discussed and taken into account
in the rationale used to justify the case study transfer.
Where a potential improvement is identified, it would be evaluated, with usage data recorded
both before and after. Where potential improvements could not be applied, or trial results
are found to be unacceptable, the study would provide appropriate supporting documentation.
Any unique plant features or conditions preventing such application of cleanup solvent usage
improvements would be identified.
Work procedures an^ material and equipment changes that have potential for «*^wing the
use of c*TOPing solvents would be included in this improvement study. All the potential
improvements may not be applicable to other motor vehicle manufacturing facilities inasmuch
as some will require conditions that are available only at specific plants. For example,
efficient collection of purge solvent may only apply where high volume painting is done with
automatic spray guns designed with that capability. For various reasons, including retrofit
D-4
-------
cost, plant specific configuration, and production materials in use, incorporation of such
improvements may not be feasible in every plant industry-wide.
RACT must address "technological and economic feasibility* through evaluation of actual
VOC reduction, cost, and feasibility of all factors involved in a decision to change a proven
material or procedure. For example, there would not be a net VOC reduction if a cleaning
material containing only half as much solvent requires twice as much material to perform the
same job. Likewise, there is an identifiable cost burden if a lower VOC cleaner or
procedure produces an equivalent cleanup but requires twice as much labor and/or costs more
per gallon. An acceptable cleaning liquid for one operation may not be feasible for another
if different materials, shapes or surfaces are being cleaned.
MVMA members do not support, nor does this study propose to retafrn$h, a cleanup solvent
RACT standard based on usage per unit because there are too many other variables. A
typical plant painting 30 units per hour does not generally use half as much cleanup solvent
as one painting 60 units per hour. There is a given amount of cleaning required once a
facility has been used regardless of the number of units produced. Among other things, the
amount of cleaning varies depending on the coating material used (chemical nature and ease
of clean up), equipment (complexity and shape of equipment), and the parts being sprayed
(shapes producing more overspray, and complexity of vehicle model mix).
Maintaining the ability to produce a quality product is also a major MVMA concern. The
proposed MVMA study would show those solvent cleanup operations that are important for
quality. One level of cleaning may be needed periodically for appearance, but that same
level of cleanliness may not be adequate for quality. An area inappropriately cleaned may
cause defects on a vehicle. For example, paint particles on overhead equipment that were
not removed regularly, have led to multiple "droppings" and defects on the tops of units
being painted that had to be repaired. Even though cleanup is an indirect" use of material
and labor, its importance to overall quality and productivity should not be minimiMH To do
so could lead to arbitrary and erroneous conclusions on what constitutes RACT for cleanup
solvents.
Recordkeeping has been demonstrated as a viable and acceptable control tool as part of the
Automotive and Light Duty Truck "Protocol" and would be the foundation for performing
the proposed study. If accurate records are kept on cleanup solvents entering and leaving a
plant,, then currenr v appropriately modified material usage records and material balance
calculations, such as those already being used, should present an adequate picture of cleanup
solvent usage in each applicable plant.
The recordkeeping required for such a study to identify usage is initially much greater and
requires more detail than for ongoing tracking and control purposes. Among the major
benefits anticipated for MVMA members in this proposed study would be the identification
of realistic key inventory, usage, and control points. Such control points could be used for
recording and reporting cleanup solvent usage once rules and permits are established for
D-5
-------
plants in each state. Continuing detailed records for individual point sources (i. e., a topcoat
booth) on a routine basis would provide little, if any, environmental benefit, be replete with
potential inaccuracies, and not be productive. This is in part due to the feet that many
cleanup solvents are supplied directly to multiple spraybooths, and/or obtained from a single
plant source, rendering accurate tracking of the quantities of solvent used at a specific point
source very difficult and burdensome, if not impossible.
In the highly competitive industrial sector where resources must be applied productively,
unnecessary recordkeeping must be kept to a minimum. For example, it should not be
necessary to show that for a gallon of solvent used in the cleanup of a spray booth that one
oz. was used to clean spray gun nozzles, twenty ozs for "wiping down" an automatic
reciprocator, and the other 107 ozs. broken down by usage within the spraybooth. It should
be sufficient to record that one gallon was used to clean the spraybooth. Likewise,
estimating the usage of one, twenty and 107 ozs. should be sufficient so long as there is full
accounting for the entire gallon. Further, it should not be necessary over the long run to
detail that five gallons of solvent were used to clean the Main Enamel booth and five gallons
were used to clean the adjacent Tutone booth so long as the total ten gallons are recorded. A
similar rationale can and should be applied to the reporting of data.
The MVMA approach will identify appropriate recordkeeping control points as well as
opportunities for potential emission reductions that are unique to each plant and its
capabilities.
In summary, the major elements of this proposed study and the content of the sections are as
follows:
Identify Cleanup Solvent Usage
Identify and Critique Potential Improvements
Evaluate Most Promising Improvements
Prepare Report Summarizing Results and Recommendations
Project Schedule
Followup Actions
The fbfiORl&g areas would be included in the proposed study to identify cleanup
solvent usage:
Body Shop
PaintShop
Trim Shop
Chassis Area
Final Prep Area
General Manufacturing Maintenance Areas
D-6
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IL Tdfflltifr *** fatigue Potential Improvement*
Potential improvements found in the study that could reduce cleanup solvent use
would be critiqued and screened by plant management for possible adoption. The
report in item VI below would provide the rationale should any potential improvement
not be trialed for adoption.
m.
Those promising improvements that appear beneficial in reducing cleanup solvent
usage will be scheduled for appropriate trials, with both before and after usage
recorded and evaluated. They will include:
Material Changes
Materials normally evaluated for solvent reduction, cost, usage and labor effect
. in motor vehicle operations include caustic cleaners, lower VOC cleaners and
peelable type boom coatings. The evaluation and decision to incorporate an
alternative material such as a cleaner requires site-specific analysis. Many
factors determine the effectiveness of a cleaner. These include the type of
coating to be removed, time available for cleaning, amount of material to be
removed, the type surface being cleaned (walls of glass and stainless,
galvanized or mild steel; configuration and detail of equipment, etc.) as well as
physical booth constraints such as piping, structural steel present, and space
between equipment.
Equipment and Facility Changes
Examples of equipment that could be included in the evaluation study are high
pressure water equipment to reduce solvent stripping, floor scrubbers, and
removable or replaceable equipment covers. For equipment and facility
changes or improvements, not all plants are expected to be capable of
incorporating a given change. Booth design, specific operations occurring
within a booth, existing equipment within a boom and availability of space to
any retrofit must be considered. In addition, paint quality
must be carefully considered when any change is contemplated for the
paint shop. A faulty trial can produce many vehicles requiring repair before a
problem can be reversed.
IV. Prepare Eqwt Simnm^jrinf R**"1** and
A summary report would be prepared incorporating study data, with a narrative on
each area of study. The report will provide a summary of the positive and negative
aspects of those material, process and cleanup changes found to be reasonably
D-7
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effective. Recommendations would be made based on the study results at each
applicable RACT plant
V.
A mutually appropriate schedule will be developed between each affected plant and
state or local agency for the proposed study.
VI. Follow-up Actions
Based upon the study results, plans for implementation would be developed in
cooperation with EPA, State or local control agency representatives. Consideration for
operational flexibility and for equivalency of reduction by alternative means over the
longer run, will be needed for any material, process or procedural changes to be
implemented. It is anticipated that individual company representatives would work as
needed with EPA, State or local agencies to incorporate cleanup solvent plans into
permits on a timely basis.
D-8
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APPENDIX E.
CASE STUDIES
-------
APPENDIX E.
CASE STUDIES
Many companies and industrial facilities now use cleaning
solvent accounting systems. They do so routinely as with other
raw materials. This section reports on several plants, most of
which (1) track usage at a level comparable to the UOS concept,
(2) account for purchase costs by department, and (3) account for
waste and disposal cost on a plantwide basis.
Many of these plants have analyzed the resulting data to
ascertain which areas (unit operations) within the plant would
most^benefit from changes in cleaning practices, and they have
i
implemented changes. A few of these facilities implemented
reduction programs or techniques before initiating their
accounting systems, but plant management expects to use
information from the systems to quantify the effects of the
changes and to identify additional reduction techniques.
The general consensus by the plants is that the overall
benefits and cost savings of the changes outweigh the costs to
implement and maintain the accounting system. The benefits
reported by these plants include reduced cleaning solvent usage,
waste, emissions, and costs related to both solvent purchases and
waste disposal. In some instances, plants also report reductions
in State*imposed emission fees. One facility reduced its usage
of one cleaning solvent by 76 percent. Another changed
production schedules so that fewer cleanings were needed. They
reduced the amount of waste disposal by 35,000 gallons (gal) in
1 year and saved $100,000. Another plant reports having reduced
E-l
-------
its solvent usage by 20 percent in 1 year due to changes in
several cleaning procedures.
Many facilities have recordkeeping systems that record
material usage for inventory, production, waste disposal, or
other purposes that are similar to the needs of a solvent
accounting system. While some may not currently track cleaning
solvent, the necessary information to do so could be incorporated
into the existing tracking programs. For example, one facility
in the adhesive manufacturing industry has initiated programs
tracking production materials.1 This plant will eventually
incorporate all cleaning solvents with the expectation that data
from the tracking system will be used to identify techniques to
reduce operating costs associated with cleaning.
Each of the following case studies provides details of
different solvent accounting and management systems that have
been implemented. Each is presented with an introductory
discussion of the approach, followed by specific details on
accounting procedures, reduction techniques implemented, and the
resulting environmental impacts. Costs related to implementing
the solvent accounting systems and reduction techniques are
presented in Chapter 5 and Appendix 6.
E.I CASE STUDY A2'3
A facility in the fiberglass boat manufacturing industry,
Facility A, implemented a solvent accounting system that tracks
the amount of cleaning solvent issued to each department (cost
center) and the amount used per boat. The accounting system also
tracks the total (plantwide) amount of spent solvent, or waste
generated, from cleaning. After analyzing the resulting
information, management encouraged substitution of specific .
solvents and restricted the use of others. Significant
reductions in use, emissions, and waste disposal resulted.
Although one of the changes made was a greater transition to use
of an "exempt" solvent, the case study demonstrates use of a
solvent accounting system and subsequent management remedial
activities.
E-2
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The plant uses solvents to clean spray guns, tools, and
workers' hands. Acetone, Tipsolve (a mixture of methylene
chloride, 1,1,1-trichloroethane, acetone, and toluene), lacquer
thinner, 1,1,1-trichloroethane, alcohol, and naphtha are
traditional solvents used for cleaning. Dibasic acid ester (DBE)
was introduced in 1990 and has replaced much of the Tipsolve
usage.
The solvent accounting system tracks actual allocations of
cleaning solvent to each department and the total (plantwide)
amount of spent cleaning solvent that is shipped offsite for
recycling or waste disposal each month. Historically, this plant
tracked acetone and Tipsolve, the two major solvents. After its
introduction, the plant incorporated DBE into the system.
Their normal procedure is to estimate emissions as the
difference between usage and total waste. However, because total
waste includes both spent solvent and contaminants, it is
periodically analyzed to determine the contaminant level, and at
the end of the year, a correction is made to more accurately
estimate annual emissions.
At this plant, the accounting system distributes the cost of
solvents as an overhead expense to user departments based on the
historical distribution of usage. The plant is now considering
using the allocation records to charge user departments on an
actual-use basis. At this plant, waste disposal costs are not
back-charged by department, but rather are charged to the
maintenance department, which is responsible for collecting and
disposing of hazardous waste.
The plant made a number of changes in its cleaning program.
The solvent accounting system has documented the impact of these
changes on usage rate, emissions, and collection rates for
recycling and waste disposal. Reductions occurred both because
of these changes and because of reduced production rates. At the
end of the year, the plant normalizes only Tipsolve emissions
relative to production levels (as described below) but believes
that overall, normalized solvent usage, emissions, waste
generation, and cost have all declined.
E-3
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Solvent accounting helped management identify at leaat one
example of how acetone was clearly being wasted. As production
declined, acetone use remained nearly constant because the daily
allocation to each employee did not change. This procedure
increased waste because unused solvent had to be disposed; it
could not be returned to storage. To correct the problem, daily
employee allocations of acetone were reduced from 5 to 2.5 gal.
Five-gal safety cans are gradually being replaced with 2.5-gal
cans. Tighter lids are being required to prevent emissions. The
reduction in unit issue of acetone has reduced not only usage but
also the amount of waste generated. Cost savings are dual, both
the purchase cost of solvent and the cost of waste disposal.
To facilitate the switch from Tipsolve to DBE, management
placed limits on individual usage of Tipsolve and allowed
unlimited use of DBE. In April 1990, prior to the changeover,
management issued an allowance of 5 gal/d of Tipsolve per
production line. In September 1990, when DBE was introduced,
management further restricted Tipsolve use to 2.5 gal per line
but allowed unlimited access to DBE. Management verbally
encouraged employees to use even less Tipsolve..
Tipsolve usage from September 1990 to February 1991 showed
a steady decrease from 484 gal per month (gal/mo) to 114 gal/mo,
a 76 percent reduction in usage. (This trend is shown in
Figure E-l). Total usage has since continued to decline, as has
the amount of waste Tipsolve generated. The plant has
calculated a "normalized emission rate" based on production;
emissions for 1990 decreased by 34 percent over 1988 and 1989.2
Emissions for 1991 decreased 83 percent from 1988, and a
reduction of 95 percent over 1988 is expected by the end of 1992
or early 1993.
Usage of DBE, also shown in Figure E-l, increased from 0 to
90 gal/mo from September 1990 to February 1991. Since
February 1991, the DBE usage has declined as employees have
improved application procedures. The DBE is less volatile,
employees do not need to soak rags as with Tipsolve, and DBE can
E-4
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500-
450-
400
350
o
300
"8 250
to
200
1 150
100
50
1
SEP OCT NOV DEC JAN
For 1990 to 1991
FEB
DBE USED
TIPSOLVE USED
Note: Data are not normalized for all accompanying decline in
production.
Figure E-l. Substitution of DBE for Tipsolve.
E-5
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be used longer than Tipsolve for dipping. Usage stabilized in
late 1992.
Training was provided for employees before and after the
change to DBE. The initial 90-minute training session was
attended by 75 to 100 employees: It presented a description of
DBE, how to handle it, an explanation of why the switch was being
made, and a lengthy question-and-answer period. In a followup
session, employees provided feedback on the performance of and
problems with DBE.
E.2 CASE STUDY B4
A textile company reduced its solvent usage at five separate
but geographically close textile mills by changing accounting
procedures. Under its previous accounting system, cleaning
solvent (and other supplies) for all five plants was stored in a
common location. The solvent was not inventoried (i.e., usage at
each plant was not recorded), and the purchase cost for solvent
was prorated equally among all five plants; each plant was
charged for 20 percent of the total. In effect, then, any single
mill paid for only 20 percent of its incremental solvent usage.
With the new computerized system, actual usage at each plant is
recorded, and each plant is charged for its usage. Solvent
purchases declined after introduction of the new system.
E.3 CASE STUDY C5'6
Facility C, in the paper and vinyl coating industry,
implemented a solvent accounting system in which cleaning solvent
usage is tracked at each coating machine and parts washer
(i.e., two types of unit operations). Plant management believes
that this accounting system will provide valuable information in
its effort to reduce the usage, waste disposal, and associated
costs. Although the plant implemented several new cleaning
procedures in 1991, before implementing the accounting system in
April 1992, management expects the accounting system to help
identify other possible efficiencies in cleaning procedures.
Numerous VOC-based solvents are used at the plant including
methyl ethyl ketone (MEK), ethyl acetate, and toluene. Coating
machines are flushed with solvent, and various parts are removed
E-6
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from the coating machines and dipped in wash tanks.
Historically, these cleaning activities were performed after each
production run. (Their coating machines are vented to a control
device during cleaning; wash tanks are not.)
In late 1991, this plant implemented both a process change
and several changes in cleaning procedures that have reduced
solvent usage, emissions, and waste generation; The process
change eliminates some cleaning steps by scheduling compatible
coating formulations successively on the coating machine. One
work practice change is to reuse cleaning solvent until it
becomes too contaminated. The plant now also restricts the
cross-sectional area of wash tanks and the amount of solvent the
wash tank may contain. New, smaller, wash tank equipment was
purchased that reduces the solvent*to-air interface. Management
standardized cleaning procedures that operators are to follow.
Floor cleaning with MEK, an extremely volatile solvent, was
eliminated. Floors are now cleaned with an aqueous solution (The
facility reported that this change had a relatively small impact
compared to the other changes they made.).
Although the plant recognizes reductions achieved by the
changes, all are not quantifiable because the changes predated
implementation of the accounting system. Significantly, however,
records of cleaning waste disposal indicate a reduction of
35,000 gal from 1991 to 1992.
The plant implemented the accounting system in April 1992
and plans to consider additional changes after collecting data
for a year. Tracking will continue to provide data that will be
used to quantify the benefits of subsequent changes relative to
the base year.
Operators now manually record the amount of solvent used to
clean each coating machine and the amount added to the wash tanks
(parts cleaners) to clean removable parts. The information is
subsequently entered into a computer data base. Operators spend
approximately 5 minutes per day (min/d) recording information for
each of 19 machines, and one spends 0.5 hour per day (hr/d)
entering the information into the data base. Analyzing and
E-7
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compiling the information to identify changes or to track trends
requires an average of 0.5 hr/d. The same employee enters and
analyzes the cleaning data. The plant used an existing computer,
and 8 to 10 hr were devoted to developing the data base
spreadsheet.
The costs of solvents used for production and cleaning, as
well as disposal costs, are charged as overhead expenses. Waste
from cleaning is tracked by the safety and environmental
department. All waste solvent from the plant is from cleaning.
The labor required for each cleaning has not changed at this
plant, but the number of cleanings per year has declined due to
scheduling changes. The total manhours per year on cleaning has
declined.
Because tracking of cleaning solvents at the plant required
changes on recordkeeping forms, initial training sessions were
held for eight operators and supervisors to explain the new
procedures; a total of about 14 manhours were devoted to these
sessions. Additional training for operators is an ongoing
process that is conducted by the employee who evaluates the data
base information. This employee sends memoranda to management
and operators clarifying issues that appear to be problems or to
implement new procedures. He also chairs a bimonthly quality
improvement meeting. Total manhours in ongoing training are
about 5 per month.
E.4 CASE STUDY D7'8
Facility D, in the coated films and paper industry,
implemented a solvent accounting system in which cleaning solvent
usage is tracked by individual coating machine, mix tank, or wash
tank (parts cleaner). Based on information it provided, the
plant has also implemented changes in cleaning procedures.
Numerous small programs were initiated to reduce solvent usage
and waste generation. Management expects to identify more
cleaning solvent usage and waste reduction techniques. A new
system with special material tracking abilities for product
formulations will be started in 1993. It will allow real-time
input of solvent usage into a data base by operators.
E-8
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Cleaning activities at the plant include flushing coating
machines and pipes, flushing and wiping tanks, and dipping parts
in wash tanks (parts cleaners). Acetone is the most common
solvent. No limits are placed on the amount that employees can
use; the amount used is based upon the operator's judgement of
his or her needs. Changes in procedures may be implemented
without supervisory review and approval. Usage of solvents is
manually recorded on mix tickets on the basis of cleaning one
machine, one tank, the parts washer, etc. These tickets are
first routed to the inventory department, where a clerk enters
information into a computer for inventory control. The
information is later entered into a second data base by a manager
in the environmental department. Most equipment is vented to a
control device during cleaning, and emissions to the atmosphere
due to cleaning are reportedly very small.
Each department within the plant is charged for the actual
materials it uses and is allocated appropriate waste disposal
costs as explained below. Waste solvent information is kept by
the solvent recovery department. The total cost of waste
disposal is reported to the environmental department, which in
turn, allocates costs to individual departments based on the
usage information reported on the mix tickets.
Information from this solvent accounting system has been
monitored over the years to help management identify areas to
reduce usage. Several changes in cleaning procedures have been
made, such as use of the "third-cycle rinse solvent" for the
first rinse cycle of next cleaning. Some of the dirtiest solvent
from the first rinse cycle is then used in production
formulations. Additional reductions in usage have been achieved
after several small programs to investigate possibilities. In
one, operators tried using less solvent to clean tanks, in some
instances only half of normal use. The results were acceptable,
and the smaller amount is now used for tank cleaning. In another
program, operators discovered that merely soaking a tank
(allowing it to sit full of solvent) for a period of. time cleaned
as well as did rinsing it several times. Less solvent is needed
E-9
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to clean a tank. Downtime increased, of course, so a compromise
of soak time and the number of rinses was necessary.
No one change has resulted in major reductions, but
collectively, numerous changes have led to sizable reductions in
both usage and waste generation. From 1990 to 1991, cleaning
solvent usage declined 20 percent. Waste generation was reduced,
but the plant did not track or keep records on the amount of the
reduction.
The plant reports that costs exceeded savings in the first
year following implementation of the accounting system. Within a
year or two, as the reduction techniques were phased in, savings
began to exceed costs. The plant did not quantify the costs but
indicated they are low. For example, recordkeeping costs are
incidental because operators spend little time recording chemical
usage.
The accounting program will be modernized in 1993 using a
new plantwide computer system. Operators will directly enter
information into the data base rather than on mix tickets. The
new equipment , which will cost $2 to $3 million, was justified
for process purposes. Incorporation of a chemical tracking
program is a minor incremental use and tracking of cleaning
solvent even smaller. The company was unable to estimate the
incremental cost of the cleaning solvent accounting system to the
base computer system's cost.
E.5 CASE STUDY E9'10
Facility E, in the can coating industry, implemented a
solvent accounting system that tracks process materials,
including cleaning solvents. This accounting system resulted
from the South Coast Air Quality Management District's (SCAQMD's)
Rule 109, which requires coating facilities to record solvent
used to clean equipment and to calculate emissions from cleaning
practices. In 1991, the plant began to enter solvent usage into
a computer data base, and limits were placed on the amount of
solvent to be used for cleaning the equipment. The plant also
implemented a solvent substitution program. Records reveal that
these practices have resulted in reductions in usage, waste
E-lO
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generated, and emissions. Further, after analysis of accounting
data, the plant identified areas of apparent "overuse" but has
not yet taken remedial action.
Solvent accounting procedures at this plant have evolved
over the years. Prior to Rule 109, daily solvent usage and waste
generation records were kept on a plantwide basis. After passage
of Rule 10911 in 1989, operators manually recorded the actual
solvent usage for each coating machine and wash tank (individual
unit operations). In 1991, the plant employed a consultant to
develop/implement a software system for tracking solvent usage on
their existing computers. Daily, a manager enters data from the
usage records into the computer data base. The system is
programmed to calculate VOC usage based on the total solvent
usage data and the compositional analysis of the solvents. It is
also programmed to compare the actual usage rates with accepted
rates and automatically generates a notification if overuse
occurs. The amount of waste solvent collected from cleaning is
recorded on an overall plant basis, wastes are not segregated;
coating and cleaning solvents are collected together.
Emissions are calculated by two procedures. First, Rule 109
requires daily records of emissions, assuming they equal usage.
The plant realizes this procedure overestimates emissions because
the plant collects some spent solvent for disposal. (At the end
of the year, therefore, the plant also estimates actual emissions
based on the difference between usage and the VOC content of the
waste. Analyses show the waste is about 71 percent VOC.)
Each department is allocated a quantity of solvent for its
cleaning needs. Supervisors distribute cleaning solvents,
thereby limiting operator access. The plant also provides
specific guidelines for its operators on the amount of solvent
used for cleaning each coating machine. (No such limitations on
solvent use are placed on wash tanks.) These guidelines were
developed from information collected by the solvent accounting
system. The department and equipment guidelines and supervisory
distribution of solvent have been in effect since 1991.
E-ll
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Cleaning solvents are overhead costs charged to a department
on the basis of actual usage. Waste disposal costs are borne by
the plant.
Plant management investigated solvent substitution and in
1990 began using glycol ether, a low-vapor-pressure solvent, in
place of methyl isobutyl ketone and MEK. The plant changed to
aqueous coatings and adhesives for several of its operations in
the spring of 1992 and, with this change, also switched to
aqueous cleaning solutions to reduce both employee exposure and
emissions. Most equipment and the floors at the plant are now
also cleaned with aqueous solutions. Some cleaning procedures,
such as flushing coating equipment, wiping rollers, and dipping
parts into one wash tank, however, still involve the use of VOC
solvents.
The plant reports that implementing and maintaining the
accounting system has not been burdensome. Operators spend a
total of 3 hours per week (hr/wk) recording usage information.
One manager spends approximately 2 hr/wk entering information
into the data base. The plant's consultant annually evaluates
and analyzes information in the data base.
The plant has reduced cleaning solvent usage and emissions.
Management attributes the reduction to both the accounting
practice and the allocation limits but affirms that the reduction
is primarily due to the accounting, which has made employees
conscious of their individual solvent usage. Emissions declined
65 percent (from 10 to 3.5 tons) from 1988 to 1991. The plant,
as required by the rule, assumes usage and emissions reductions
are equal. Thus, waste disposal rates have remained constant.
The plant plans to use the information from the accounting
system to identify other areas of waste and overuse. The plant
reports that such identification efforts are much easier when
information is recorded at the equipment level rather than the
plant level.
The plant has historically trained employees on cleaning
practices. When the data base was implemented and the
limitations on solvent use began, management explained that
E-12
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solvent was being limited to reduce usage and emissions.
Further, they explained that the amount of solvent used would be
compared to the allocated amount of solvent needed for cleaning
equipment. Training for the employee that enters information
into the data base required 6 hr and was provided by the plant
consultant who also maintains the computer system.
E.6 CASE STUDY F12
A plant in the can coating industry, Facility F, implemented
a solvent accounting system that tracks solvent used for cleaning
both equipment and parts. The facility is subject to several
SCAQMD rules, including Rule 109 (explained for Facility E).
Prior to Rule 109, the plant tracked cleaning solvent for each
unit operation for the inventory and to monitor the amount of
solvent used for cleaning. Accounting procedures did not change
after Rule 109, but the plant did implement a_few successful
reduction techniques.
Cleaning at the plant includes wiping rollers used in the
coating operations and dipping coater parts into wash tanks
(parts cleaners). Butyl Solvent, composed of xylene and
ethylene glycol, is used for cleaning. Cleaning is required
between customer orders. General guidelines on the amount of
cleaning solvent needed for particular tasks were obtained from
.an audit conducted when the plant first opened in 1985.
Operators manually record cleaning solvent usage for each
coating machine, press, and wash tank. They spend approximately
30 to 40 min/d manually entering usage information on log sheets
and double-checking their numbers. A manager spends
approximately 10 to 15 min/d reviewing records from operators for
inconsistencies, and if more solvent is used on a particular
piece of equipment than the amount normally required, the
operator is questioned. The information is later added to a
written inventory by a manager, and the amount used is subtracted
from inventory. Handling accounting activities related to
material usage consumes a major part of one manager's time.
The cost for cleaning solvent is charged to each department
based on actual usage. Accounting by department has been a
E-13
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driving force in reducing usage because the accounting provides
the department manager, who is striving to reduce costs, with
actual usage and cost information. Waste from cleaning is not
tracked by equipment but rather on a plantwide total basis, so
these costs are not charged to individual departments.
Evaluation of information from the accounting system
revealed several work practices that resulted in overuse of
solvent. The plant then implemented a few changes. For example,
unnecessary cleanings, such as cleaning ink pails when they are
ready to be disposed of offsite, were eliminated. The use of
spray bottles was also discontinued, which has helped to decrease
the evaporation rate of cleaning solvent.
While the plant did not quantify specific results of their
program, management reports these changes led to reductions in
both cleaning solvent usage and waste generation. Careful
attention from management on recording practices has made
operators more aware of their solvent usage, and this awareness
has also led to reductions.
It is also likely that the changes in work practices reduced
emissions. In fact, the plant reports reductions because it
assumes emissions equal usage, as required by Rule 109. However,
the plant also collects some spent solvent for waste disposal,
which means it overestimates emissions using this assumption. It
also means the actual emission reductions cannot be calculated
without before and after usage and waste data, which the plant
did not share with EPA.
Operators are trained regarding cleaning practices. Monthly
departmental meetings are held that include discussion of topics
such as production efficiency, recordkeeping inconsistencies,
safety, and refresher training for a variety of practices. These
meetings last approximately 1 to 1.5 hr and approximately 35 to
40 people attend. A manager holds an additional monthly meeting
to discuss any planned changes in practices or problems that have
occurred.
E-14
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E.7 CASE STUDY G13'14
Facility G, in the coil coating industry, has implemented a
solvent accounting system that tracks solvent usage for equipment
cleaning (i.e., a unit operation). This facility is also subject
to California's SCAQMD Rule 109, which requires recording of
solvent used for and emitted from cleaning. The plant has also
implemented a solvent reduction program that changed some
cleaning practices. The accounting system and the reduction
program are reported to have reduced cleaning solvent usage,
waste, and emissions.
Coating equipment is cleaned at the plant with
Cleanup Solvent1*, which contains MEK, toluene, isopropanol, and
petroleum distillate. Cleaning is necessary between customer
orders. Coating equipment (the paint pan, roller machinery, and
roller surfaces) is cleaned as one unit operation.
The plant has manually tracked solvent usage on a unit
operation basis since the plant first opened to confirm that
expected inventory was used on schedule. After Rule 109, this
information has been entered into a computer data base by a clerk
in the production control department.
The quantity of cleaning waste generated is recorded
plantwide. It is easy to track because it is generated in only
one area of the plant. Also, except for a small amount of
coating solvent that remains in the paint pan, waste cleaning
solvent is collected separately from other waste.
Emissions are estimated by subtracting the amount of waste
collected from cleaning (corrected.for the contaminants) from the
solvent used. These emissions are captured and vented to a
control device. The capture and destruction efficiencies of the
control system are used to calculate the actual emissions to the
atmosphere.
The plant implemented a few cleaning procedural changes to
reduce solvent usage and waste. The plant provides guidelines
for operators on the specific amount of solvent needed for
cleaning equipment. It was determined by trial and error that
the least possible amount of solvent that cleans effectively is
E-15
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2 gal per coating machine. This guideline has been in effect
since shortly after the plant opened. The plant has also
prescribed changes in cleaning practices such as scraping coater
pans and rollers to remove excess coating material prior to
cleaning.
These changes reduced solvent usage, waste, and emissions
related to cleaning between 1986 and 1987. Usage was reduced
45 percent, from 40.8 to 22.4 tons. Waste disposal decreased
25 percent from 41.0 to 30.6 tons. Emissions were calculated as
the difference between usage and the VOC content of the waste,
which, according to the plant, was about 70 percent in both
years. Thus, emissions decreased 92 percent from 12.1 to
0.98 tons. (These emissions are captured and sent to a control
device, so emissions to the atmosphere reportedly declined from
0.5 to 0.04 ton.) These reductions are shown in Table E-l.
TABLE E-l. REDUCTIONS AT FACILITY G
Usage
Wastea
Emissions
1986
40.8 tons
41.0 tons
12.1 tons
1987
22.4 tons
30.6 tons
0.98 ton
Net
reduction
18.4 tons
10.4 tons
ll.l tons
Percent
reduction
45
25
92
*At 70 percent VOC.
Recordkeeping associated with the accounting system has made
operators more aware of their cleaning practices and made them
more frugal and efficient with usage. Upkeep of the accounting
system requires some labor input from operators and managerial
staff. A total for all operators of 8 hr/wk is spent recording
cleaning solvent usage, and the clerk in the production control
department spends 14 hr/wk imputing these data into the data
base. A manager then spends l hr/wk evaluating the information.
The plant provides training for all operators before they
perform cleaning. Before implementation of the accounting
system, training was provided for eight operators and the
E-16
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employees that enter and evaluate data. New personnel also
receive this training as part of their orientation. An annual
meeting, which lasts approximately 15 min and is attended by
three people, is held to provide refresher training to operators.
When the plant initiated its program several years ago, a
meeting was held to explain the planned changes and their
purposes to operators. A roundtable meeting including both
management and operators was also held when the plant began its
reduction program. Many viable ideas were presented by operator
staff, and some of the techniques implemented originated with
operators.
E.8 CASE STUDY H15
An automotive company implemented a program to reduce the
variety and amounts of chemicals, including cleaning solvents,
used by its plants and to reduce the cost to dispose of hazardous
waste. The reduction program included a team that first examined
the usage of "indirect," or nonproduct, chemicals. This team
discovered that corporatewide, the company used thousands of
different cutting oils to perform equivalent operations and that
even within an individual plant there often were many similar
commercial products used by different people to accomplish the
same cleaning. This assortment of supplies, including cleaning
materials, resulted from personal preferences of employees and
also from a large number of visits by salesmen to the plants.
Duplication produced additional inventory, storage, and disposal
costs for the plants. The team's conclusion was that normal
market forces tended to swell the number and types of products
that must be kept in inventory.
The corporation began an experimental program by hiring a
contract firm to be responsible for supplying chemicals, defining
and performing cleaning procedures (as long as production is
unaffected), and handling waste disposal for a single plant.
This firm acted as liaison between the plant and suppliers, its
responsibility was to reduce indirect or nonproduction chemical
usage and costs by various methods. It, in effect, became the
holding company for those chemicals and the resulting waste using
E.-17
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just-in-time delivery principles and minimizing inventoried
products. In previous practices, indirect chemical and disposal
costs were charged to plant overhead. With the new program, the
contract firm bids a fixed price for supplying segments of the
plant and is responsible for meeting these contractual costs.
This provides the contractor with the profit incentive to reduce
the costs of supplying the indirect chemicals. In effect, the .
experiment made these chemicals, which are incidental to the
assembly of automobiles, the major profit mechanism for the
contractor. The company has been adding plants to the program
since 1987.
The contractor has recommended several changes to reduce the
use of solvents (and the cost of cleaning). One engine plant was
able to reduce cleaning frequency by making a process change in
its honing operation. Engines "were previously honed with a
solvent-oil solution, followed by a washing operation. The
solvent-oil honing solution contaminated the washer,
necessitating emptying and cleaning the washer every other day.
After switching to an aqueous honing solution, the washer now
requires cleaning only once every 4 weeks.
Another change reduced the wasteful use of purge solvent in
paint shops. Previously, solvent was readily available to the
painters via manual valves on the solvent distribution lines
within each spray booth. These lines have been blocked at some
plants.
The failure rate of engines at one engine manufacturing
plant was reduced by improving cleaning practices. A management
team established specifications for cleanliness of engine parts
and then developed methods to meet the specifications. The
failure rate of engines has declined from 30 per month to only
2 (when the car is ready for shipping and the engine will not
start, a new engine is installed, a very costly step).
One of their plants targeted waste disposal of paint residue
from paint spray booths. This plant made changes in the
technology used to detoxify paint sludge from its spray booths
and was able to reduce disposal costs.
E-18
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The company's plants have reduced the usage, waste, and cost
of indirect chemicals by an average of 30 percent overall in the
plants that have implemented accounting and managerial techniques
and by 50 percent in some cases. One plant saved more than
$2 million on paint sludge waste disposal costs. Management
attributes its success to the accounting system, which permitted
management to identify where major quantities are used. The next
step was an aggressive effort by management to change practices.
E.9 CASE STUDY I16
Several plants in the aerospace industry have assessed their
solvent usage and subsequently changed cleaning practices to
reduce usage; others are starting or planning assessment
programs. One plant instituted a sophisticated accounting system
where employees are required to check out solvent by project and
employee number from a "chemical crib" and return any leftover
chemical for storage or waste disposal. At the same time, the
plant established limits on the amount of solvent to be allocated
for specific cleaning tasks. These procedures reportedly
achieved significant usage reductions.
In many cases the accounting results revealed that the
initial allocation limits were generous and could be reduced for
even greater savings. In response to their own assessment
programs, plants at other aerospace companies have also
implemented the procedure of dispensing solvents from a
centralized chemical crib and tracking their use. Some have also
implemented various work practice procedures (such as replacing
5-gal pour spout and immersion containers with 1-quart dispensing
bottles), solvent substitutions, and training programs to teach
good work practices and to inform employees of the environmental
benefits of reduced usage.
E.10 REFERENCES FOR APPENDIX E
1. Letter from Gelli, J., Courtald's Aerospace, to Schmidtke,
K., MRI. August 13, 1992. Summary of material tracking
information.
E-19
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2. Telecon. Randall, D., MRI, with Joyner, L., Hatteras
Yachts. July 24, 1992. Solvent accounting and management
procedures.
3. Memorandum from Trenholm, A., and K. Schmidtke, MRI, to
Serageldin, M., EPA/CPB. June 25, 1992. Site visit report
of Hatteras Yachts in High Point, North Carolina.
4. Telecon. Berry, J., EPA/CPB, with Linker, J., Wiscassette
Mills. August 12, 1992. Solvent accounting techniques.
S. Telecon. Schmidtke, K., MRI, with Irish, D., Flexcon
Corporation. August 11 and 17, 1992. Solvent accounting
and management procedures.
6. Telecon. Schmidtke, K., MRI, with Irish, D., Plexcon
Corporation. March 3, 1993. Costs and impacts related to
solvent management techniques.
7. Telecon. Schmidtke, K., MRI, with Brown, G., Graphics
Technology International. August 11 and 14, 1992. Solvent
accounting and management procedures.
8. Telecon. Schmidtke, K., MRI, with Brown, G., Graphics
Technology International. December 8, 1992. Solvent
accounting and management procedures.
9. Telecon. Schmidtke, K., MRI, with Facility E. August 27
and November 24, 1992. Solvent accounting and management
procedures.
10. Telecon. Schmidtke, K., MRI, with Facility E's Consultant.
November 25, 1992. Costs and impacts related to solvent
management techniques.
11. South Coast Air Quality Management District. Regulation I -
General Provisions, Rule 109 - Recordkeeping for Volatile
Organic Compound Emissions. Adopted May 5, 1989.
12. Telecon. Schmidtke, K., MRI, with Facility F. September 1,
1992. Solvent accounting and management procedures.
13. Telecon. Schmidtke, K., MRI, with Koenig, J., SupraCote,
Inc. September 2 and December 3, 1992. Solvent accounting
and management procedures.
14. Letter from Koenig, J., SupraCote, Inc., to Schmidtke, K.,
MRI. January 11, 1993. Costs and impacts of solvent
management techniques.
15. Telecon. Berry, J., EPA/CPB, with Mishra, R., General
Motors Corporation. 1992. Solvent accounting and
management procedures.
E-20
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16. Personal communication between Serageldin, M., EPA/CPB, and
Booth, V., EPA/CPB. 1992. Solvent accounting and
utilization procedures in the aerospace industry.
E-21
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APPENDIX F.
DRAFT TEST METHOD FOR DETERMINING THE PERFORMANCE
OF ALTERNATIVE CLEANING FLUIDS
-------
APPENDIX F.
DRAFT TEST METHOD FOR DETERMINING THE PERFORMANCE
OF ALTERNATIVE CLEANING FLUIDS
This appendix presents a draft test method for evaluating
the performance of alternative cleaning fluids. Any fluids may
be tested, but the primary intent is that it will be used to
evaluate the performance of alternatives relative to a VOC
solvent. It is a screening technique designed to determine
whether the alternative(s) cleans at least as well as a currently
used VOC solvent in a simple, standardized wiping application.
The results of this procedure may not mimic those that would be
achieved for a different scenario in an industrial setting
(e.g., spraying or wiping a complex shape). However, any
cleaning fluids that are unsatisfactory in this test can be
eliminated from consideration for more complicated site-specific
tests. This test method has not yet been validated.
F.I STANDARD TEST METHOD FOR DETERMINING THE PERFORMANCE OF
ALTERNATIVE CLEANING FLUIDS
F.I.I Introduction
Industrial plants use VOC solvents to clean numerous
contaminants from a variety of materials in different
configurations. Alternative solvents and cleaning fluids exist
that would produce lower VOC emissions from many of these
cleaning applications. This method involves comparative testing
of an existing VOC solvent with alternatives using one
standardized cleaning procedure. It is a screening technique
that identifies which alternative fluids clean as well as or
better than an existing VOC solvent. Because it may not
reproduce the plants' actual cleaning procedure, nor determine
F-l
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the effect of the alternative on the performance of coatings
applied to the cleaned surface, it is likely that additional
site- or industry-specific tests will be needed before the
alternatives that pass this screening test are adopted.
This method is based on ASTM Method D 4828-91 for
determining the practical washability of organic coatings.
Changes were made to the method to allow its use in new
applications. The changes include a wider variety of acceptable
test panel materials, contaminants, and cleaning fluids.
Procedures for evaluating the results are also different. The
cleaning apparatus and procedure were not modified.
F.2 APPLICABILITY AND PRINCIPLE
F.2.1 Appli cabi1i ty
This method applies to the determination of the relative
ease of removal of contaminants from a variety of materials/
surfaces by manual or mechanical cleaning with a sponge and
various solvents or other cleaning solutions.
F.2.2 Principles
A contaminant is applied to a test panel to represent a
typical industrial cleaning situation. One portion of the soiled
panel is scrubbed with a sponge and the existing solvent, and
another portion is scrubbed with a sponge and an alternative
solvent or cleaning solution that produces lower VOC emissions.
The performance of the alternative is then rated as (1) worse
than the existing solvent, or (2) as good as or better than the
existing solvent.
F.3 APPARATUS
1. Sponge and Holder1
2. Contaminant Applicator
3. Weight, 100 g
XA sponge, 3 by 3* by l* in. (75 by 95 by 45 mm), Part No.
AG-8116, and a metal holder, Part No. AG-8115, available from
BYK-Gardner, Inc., 2435 Linden Lane, Silver Spring, MD 20910 or a
sponge, Part No. WA 2222, and metal holder, Part No. WA 2220,
available from Paul N. Gardner Co., 316 N.B. First Street,
Pompano Beach, Florida 33060-6699 have been found acceptable for
this purpose. An equivalent may be used.
F-2
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4. Balance, Weighing Accurately to 0.1 g
5. Doctor or Bird Film Applicator, having a 7-mil (0.18-mm)
clearance by 6-in. (150-mm) film width
6. Panels of various materials, 17# by 6% by K in. (455 by
165 by 6.3 mm)
7. Washability Machine2
8. Masking Tape
9.. Straightedge, approximately 17 in. (430 mm) in length
10. Cotton Tipped Swabs
11. Medicine Droppers
12. Suction Plate, for drawdowns
F.4 REAGENTS AND MATERIALS
F.4.1 Contaminanta
Examples that may be used with this test method include, but
are not limited to pencil, crayon, ball-point pen, waterborne
felt-tip markers, grease, and mineral oil.
F.4.2 Solvents and Cleaning Solutions
Examples that may be used with this test method include any
VOC solvent or alternative cleaning fluid.
F.4.3 Test Panels
Different types of panels may be selected to match the
cleaning application. Examples include, but are not limited to,
glass, stainless steel, aluminum, and plastic. The surface may
be painted or unpainted.
F.5 PREPARATION OF APPARATUS
F.5.1 Waahafriiity Machine
Level the apparatus before use and operate at 37 ± l cpm.
(A cycle consists of a complete forward and reverse stroke.)
2Washability machine, Model AG-8100, available from
BYK-Gardner, Inc. or Model WA 2037D, available from the Paul N.
Gardner Co., have been found suitable for this purpose. Other
straight-line wash testers may be adapted to meet the
requirements of this test method.
F-3
-------
P.5.2 Sponoe and Holder
Add sufficient weight to the holder in the form of metal
sheets or other flat weights to give a combined weight of 1000 g,
including the dry sponge.
F.5.3 Test Panel
Prepare paint coated panels by the following procedure.
Stir the material thoroughly and strain, if necessary, to remove
all skins and particles. Draw down the coating on the panel.
Apply the coating in 3 to 4 s from end to end to prevent pin
holes or holidays in the film. Air dry all panels in a
horizontal position for 7 days in a room maintained at 73 ± 3.5°F
(23 ± 2°C) and 50 ± 5% relative humidity as described in
Specification D3924, or under conditions specifically applicable
to the material under test. Prepare enough panels with each
paint for all the projected tests.
Before use, clean the top of the test panel (painted or
unpainted) to be sure it is free of specks.
F.6 PROCEDURE
F.6.1 Application of Contaminants
l. Apply the selected contaminants to the test panel (or
coating on the panel) in one straight line parallel to the length
of the panel for the manual method of cleaning, or in a pair of
lines perpendicular to the length of the panel for the mechanical
method of cleaning.
2. Apply solid contaminants using the apparatus shown in
Figure F-l. Insert pencil, crayon, pen or similar items into the
appropriately sized hole and secure its position so it extends
Itf in. (40 mm) beyond the panel (see Figure l(a)). Secure the
medium in position with a piece of masking tape (see
Figure 1(b)). Put the wooden applicator panel at one end of the
test panel and place the 100-g weight on its top face at the end
nearest to the marking device, as shown in Figure l(b), securing
it with a piece of tape. Allow the nonweighted end of the wooden
applicator panel to rest on the surface of the test panel, then
hold it by the outer edges and pull it along the entire length of
the panel (see Figure l(c)).
F-4
-------
1a
1b
1c
6'(152.4mm)
lOOg
O ":.
T
'
Elevation
or Side View
1/2" (12.7mm)
Wooden Applicator Panel
1/8" (3.18mm) radius
Grip area to pull panel
located here on each side; approx.
* 5/16" (8mm) hole bored at approximately
45° angle (for pencil and pen)
* 5/8" (16mm) hole bored at approximately
45° angle (for magic marker).
Masking Tape
T
3" (76.2mm)
i
-»
./
Plan or
Top View
Wooden Applicator Panel
Test Panel
Paint
T
-lOOg Weight
Wooden
Applicator
Panel
Figure F-l. Contaminant application.
F-5
-------
3. Apply liquid contaminanta using hand-held cotton-tipped
swabs. Immerse one end of a cotton-tipped swab in an appropriate
solvent or cleaning solution and allow to remain totally immersed
until the cotton tip is saturated (approximately 10 to 15 sec).
Remove the tip from the liquid and apply the first of two
parallel lines to the test panel using the straightedge to assist
in drawing the lines. Adjustment of pressure on the cotton tip
may be required to provide a line of uniform intensity.
Reimmerse the cotton tip in the liquid and then draw the second
line. Repeat with a clean or unused cotton tip for each liquid
being used. Permit the contaminants to dry at least 1 hr under
the same temperature and humidity conditions as in 5.4.
Note lOnly one contaminant may be tested at one time.
Typically, as noted above, this will mean the application of one
line for manual cleaning or two parallel lines of contaminant for
mechanical cleaning. As shown in Figure P-2, one section of the
panel will be used to test the VOC solvent and another section
will be used to test an alternative cleaning fluid. However, the
panel may be long enough to allow evaluation of more than one
alternative cleaning fluid in a single test.
F.6.2 Cleaning
1. Soak the sponge in the solvent or solution at ambient
temperature until saturated. Remove the sponge and squeeze with
one hand until no more liquid drips from the sponge. Replace the
sponge in the holder and pour 15 ± 1 mL of solvent or cleaning
solution on the exposed face of the sponge.
2. Apply 5 mL of solvent or cleaning solution in parallel
bands to each contaminant line.
F.6.3 Manual Method
1. Place the sponge and holder at one end of the panel so
that its long axis is perpendicular to the length of the panel
(see Figure F-2). Rub the sponge across the panel over the
contaminant lines/ exerting minimum downward pressure. Continue
rubbing until all the contaminants are removed or to a maximum of
100 cycles. If all the contaminants are removed prior to
F-6
-------
Direction of Sponge
Additional Test S
(Use Option
Mechanical Wash
Section One (Alternative Additional Test Section
(VOC Solvent) Cleaning Fluid) (Use Optional)
m
Sponge Holder
(Top View)
u>
0
t
-
^
^
C
1
s*
n^"~
" *,
x
^
\
k>ntaminant Area
Manual Wash
Weight
Sponge Holder
(Side View)
(Tape On),
Grip Area
Sponge Holder
(Top View)
Grip Area
Sponge
Figure P-2. Panel layout and brush holder diagram
F-7
-------
100 cycles, stop and record the number of cycles before
proceeding to 6.5.
F.6.4 Mechanical Method
1. Place the sponge and holder at one end of the panel so
that its long axis is parallel to the length of the panel (see
Figure F-2). Attach the sponge and holder to the cable of the
washability machine. Allow the sponge to travel a maximum of
100 cycles. If all the contaminants are removed prior to
100 cycles, stop and record the number of cycles before
proceeding to 6.5.
2. Remove the test panel and evaluate the condition of each
in the path of the sponge and rate as follows:
a. Worse than existing solvent
b. As good as or better than existing solvent
When a contaminant is removed prior to 100 cycles, note the
number of cycles in which each contaminant was removed.
F.7 REPORT
F.7.1 Report the Following Information
1. Type of contaminants, solvents, or cleaning solutions,
and washing method used and the results obtained in 6.5.
2. Any contaminants that were removed in less than
100 cycles, and
3. Any deviation from the recommended procedure.
F.S PRECISION AND BIAS
1. Precision Unknown.
2. Repeatability Unknown.
3. Reproducibility Unknown.
4. Bias Unknown.
F-8
-------
APPENDIX G.
PROCEDURES FOR DETERMINING VOC EMISSIONS FROM
SPRAY GUN CLEANING
-------
APPENDIX G.
PROCEDURES FOR DETERMINING VOC EMISSIONS FROM
SPRAY GUN CLEANING
This appendix presents procedures for analyzing cleaning
solvent usage and emissions for several subcategories of the .
spray gun cleaning unit operation system. This appendix focuses
on spray gun cleaning for two reasons. First, more quantifiable
data are available for this unit operation than for any of the
other eight unit operations identified by this study. Second, as
noted in Chapter 2, more emissions are associated with this unit
operation than with any of the others. Similar analyses could be
developed for the other UOS's.
A total of six subcategories were developed, based on the
cleaning procedure used. Four are for cleaning manual guns and
two are for cleaning automatic guns: (1) uncontrolled manual
cleaning, (2) manual cleaning with collection of "once-through"
solvent, (3) manual cleaning with recirculated solvent,
(4) cleaning manual guns with a commercial gun washer,
(5) automatic cleaning with collection of "once-through" solvent,
and (6) automatic cleaning with recirculated solvent. In most
cases, the plant has a choice, and the choice affects both the '
usage and emissions. Information from this study is used to
illustrate each of the subcategories, and usage and waste data
from several plants are used in example material balance
calculations for most subcategories.
A State agency, over a period of time, could receive
sufficient information on solvent usage for cleaning spray guns
that it would be able to develop usage factors, preferably per
unit area cleaned, with some confidence that they are
G- 1
-------
representative of the subcategories. Subsequently, those usage
factors would provide a powerful tool with which to screen future
reports on solvent usage. For example, if one knew with some
confidence that to clean a gun generally required from 4 to
6 pints per cleaning cycle and someone reported 2 (or 10), then
the State would be interested in knowing more about how that
facility did so well (or poorly).
A State agency could also develop emissions factors for each
subcategory by using the usage (and waste) information from
facility reports in the appropriate material balances. The
emissions factors would allow the State to quantify the emissions
associated with each cleaning procedure and rank the procedures.
The remainder of this chapter has five sections.
Section G.I describes the components within the spray gun
cleaning UOS subcategories and the important factors that must be
considered to secure complete material balances for each.
Section G.2 describes the four UOS subcategories for cleaning
manual spray guns. One case study is reported for the first
subcategory and three are reported for the second. No site
specific case study on commercial gun washers was available, but
data from an emissions test is presented. Section G.3 describes
the two UOS subcategories for cleaning automatic equipment and
presents information about cleaning automated spray guns in the
metal furniture and automotive industries. Section G.4 compares
the waste collection and emissions data for cleaning manual and
automatic guns. Section G.5 contains information, on spray gun
cleaning UOS costs. Section G.6 contains references.
G.I DESCRIPTION OP SPRAY GUN UNIT OPERATION SYSTEM
To estimate emissions associated with cleaning a spray gun,
it is recommended that a material balance around a UOS be
considered for that purpose. A spray gun UOS consists of the
spray gun and ancillary equipment like hoses or paint cups that
are cleaned at the same time as the gun. It should also include
solvent and waste storage vessels. The cleaning activities
include purging the gun; purging the hose or flushing the paint
G-2
-------
cup (depending on the painting equipment used); and wiping the
exterior of the gun (and the cup, if so equipped) .
Cleaning of the exterior surface is an integral activity
inherent when a gun washer is used. Therefore, to compare
emissions from different cleaning requires on an equal basis, all
spray gun UOS's must consider both external and internal
cleaning. A UOS may include more than one spray gun
(i.e., multiple guns that are cleaned by the same procedure and
with the same solvent can be included in one UOS).
As described above, six general subcategories for spray gun
cleaning UOS's were developed. When no waste solvent is
collected, the uncontrolled subcategory, the emissions equal
usage, and only the quantity of solvent used is needed to
estimate emissions. If waste is collected, as in subcategories 2
through 6, three additional factors must be considered for an
accurate estimate of emissions. These are (1) the total amount
of spent solvent generated, (2) the contaminant content of the
spent solvent, and (3) any solvent contribution from the paint.
Each of these subcategories is discussed further in Sections G.2
and G.3.
G.2 CLEANING MANUAL SPRAY GUNS
This section describes the four manual spray gun cleaning
UOS subcategories. Information from four case studies is
summarized. Analyses include (1) estimates of usage and
emissions factors normalized for the number of cleaning cycles
and the surface area cleaned and (2) the effect of the remedial
alternatives on emissions, solvent usage, and waste generation.
Although these case studies reveal useful information, none is
complete. All include some assumptions because none of the
plants maintained all of the data needed to complete a rigorous
material balance. Appendix B includes descriptions of operations
and an example material balance calculation for a spray gun UOS
from one of the case study plants.
G-3
-------
G.2.1 Uncontrolled Emissions (Subcategory No. 1)
Uncontrolled emissions is the term used when all of the
solvent used for cleaning a spray gun evaporates (i.e., no spent
solvent is generated); emissions equals usage. Figure G-l shows
how the unit operation (cleaning of a spray gun) and associated
potential sources of emissions created by cleaning can be
considered as a system (UOS) for the purposes of quantifying the
resulting emissions. The material balance for this UOS, assuming
the solvent is 100 percent VOC, is shown in equation 1:
VQ - V-L + V2 + V3 + V4 + V5 = S± (1)
where:
VQ = total VOC emissions, Ib/yr
vl* V2' V3' V4' V5 = Emissions from individual activities
within the UOS, Ib/yr
S± = total weight of solvent usage, Ib/yr
The time frame in the material balance is arbitrary; in this
case, an annual basis was used.
The first action within the UOS is transfer of solvent from
a storage drum or tank to the painting work station. This can be
accomplished by transferring a portion to a solvent bucket, as
shown in Figure 4-1. Some plants may have a solvent line from
the storage tank to the paint work station. A line would
eliminate the possibility of spillage between the storage drum
and the work station, thereby offering a distinct advantage over
manual transportation in a open bucket.
The second action is the actual cleaning activity, e.g., use
of the solvent to purge the gun, flush the paint cup for a
siphon- or gravity-feed gun, flush the hose for a pressure-feed
system, and wipe the exterior of some or all components. The
third action is post-cleaning activity, where more solvent
evaporates. Purge solvent may be discharged from the gun
directly into the air or into either a container or a wastewater
G-4
-------
(fugitive emission)
I
.
(fugitive emission)
V3
(fugitive emission)
Si
(cleaning solvent
input)
in
V4
(Fugitive emission from solvent
sprayed into air, container, or
wastewater and allowed
to evaporate)
V5
(fugitive emission)
Figure G-l. Schematic of uncontrolled spray gun cleaning unit operation
system (spent solvent directly released to the atmosphere).
-------
system from which it evaporates. Rags used to wipe the exterior
surfaces may be subsequently handled in such a way that the spent
solvent is lost before it can be collected.
The only VOC input to the UOS is in the cleaning solvent
(S1). Specific records of the amount of cleaning solvent used in
the UOS provide the best data for use in the material balance.
Alternatively, estimates may be needed if detailed (UOS-specific)
records are not kept. When usage is known in gallons, it must be
multiplied by the VOC content of the solvent (Ib VOC/gal solvent)
to determine the amount of VOC that enters the UOS.
Outputs consist of emissions from the storage tank, 'solvent
bucket (or fittings in a solvent line), surface of cleaned
components, and evaporation of spent solvent (V^^ through V5) .
Collectively, the VOC emissions (VQ) are equal to the usage
because no waste solvent is collected in the rags.
One plant (Plant I) in the electrical components industry
reported uncontrolled cleaning procedures for a siphon-feed gun.
The plant did not maintain records of solvent usage for this UOS
but estimated that the gun is cleaned 500 times per year (based
on cleaning at the end of each of two operating shifts per day,
5 days per week, and 50 weeks per year). To clean a gun, the
\
painter adds about a pint (0.93 Ib) of lacquer thinner to the
paint cup and sprays it into the air in an uncontrolled spray
booth. Therefore, annual purge usage and emissions are equal,
about 0.93 Ib VOC per cleaning -cycle and 464 Ib/yr. The exterior
of the gun and cup are also wiped occasionally with solvent, but
the amount of solvent used for this purpose was not reported.1'2
The procedure used by this plant appears typical for
cleaning this type of gun and is common to many industries,
including automobile refinishing shops. Estimates of the amount
of solvent used range from about 0.6 to 1.8 Ib/cycle (based on a
VOC content of 7.3 Ib/gal),3'4 The cleaning cycle is used as
normalizing parameter because it is available, but the time for
cleaning would be a better parameter.
G-6
-------
G.2.2 "Once-Through" With Collection of Spent Solvent
(Subcategory No. 2)
One alternative that may reduce gun cleaning emissions is to
collect spent solvent for disposal or other reuse. When spent
solvent is collected after a "once-through" cleaning, emissions..,
are calculated by subtracting the amount of VOC in the collected
spent solvent from the amount used. The extent of emissions
reduction will depend on the care and skill of operator and how
well the collection container is sealed.
G.2.2.1 Description of the UPS. Figure 4-2 shows how the
boundary was established around the UOS, the actions or steps
inside the UOS, and the input and output streams that cross the
boundary. Congruities between this subcategory and the
uncontrolled case (Figures G-l and G-2) are the solvent storage,
solvent transfer to the work station, and solvent use in
cleaning. The two primary differences are: (1) spent solvent is
collected, and (2) the total solvent collected must be adjusted
to correct for the paint solvent that is associated with the
collected paint nonvolatile matter.
Emissions occur from the same locations in both this UOS,
shown in Figure G-2 (V.^ through V5) , and the uncontrolled UOS
(Figure G-l). Additional locations for emissions shown in
Figure G-2 include paint collection containers, spent solvent
collection buckets, and spent solvent drums or tanks (Vg through
Vg). Figure G-2 also shows one VOC input stream (S1) and one
spent solvent output stream (W for waste disposal).
Measuring and recording the amount of solvent used and the
amount collected for waste disposal provide the best data for use
in the material balance. Further, samples of the waste stream
should be analyzed periodically for contaminants (nonvolatile
material) and non-VOC's (e.g., all material not determined to be
a VOC by EPA Method 24), and the difference is the VOC content of
the stream. In the absence of UOS-specific records and sample
analyses, estimates will be needed to complete the material
balance.
G-7
-------
(fugitive
emission)
V.3
(fugitive
emission)
V4
(fugitive
emission
from spent
solvent
sprayed into
the air)
Y5 v.6.
(fugitive (fugitive
emission) emission)
V7
(fugitive
emission)
V8
(fugitive
emission)
(cleaning
solvent
input)
O
I
CD
W (waste)
*NOTE: Thinning solvent associated with the paint nonvolatile matter removed from the hose and gun while cleaning must
also be included in the material balance.
Figure G-2. Schematic of manual spray gun cleaning unit operation system with
once-through solvent use and collection of spent solvent.
-------
The material balance for this UOS is shown in Equation 2:
VQ = V-L + . . . + V8 = S-L - (W) x (x,,) (2)
where:
W = total weight of waste solvent, Ib/yr
xw = VOC weight fraction of waste solvent, Ib VOC/lb waste
Because "wet" paint (residual matter from painting) is
removed during the purge, the cleaning solvent emissions
calculated from Equation 2 are underestimated by the amount of
paint solvent collected in the spent solvent container
(Figure G-2). Thus, the cleaning solvent emissions have to be
increased by the amount of collected paint solvent:
vc - vo + WP {3)
where:
Vc - cleaning solvent emissions, Ib VOC/yr
Wp = weight of collected paint solvent, Ib VOC/yr
If the cleaning and paint solvents are different, the amount
of collected paint solvent can be determined by analysis of the
waste; otherwise, the amount must be estimated. When the
composition of the solvent fraction of the waste is unavailable
or the cleaning solvent and paint solvent are identical, the
collected paint solvent cannot be determined. In these cases,
the UOS is modified to include the amount of paint solvent
originally associated with the paint solids in the waste stream
(P) as an input. (The amount of collected paint solids is
assumed to be equal to the amount of nonvolatile matter in the
waste 'stream.) The material balance is modified to calculate the
total cleaning and paint solvent emissions by adding P to the
right side of Equation 2. Assuming the cleaning solvent and
paint solvents have similar volatilities, equal portions of both
solvents are assumed to evaporate. The amount of cleaning
solvent that evaporates is then estimated by multiplying the
total emissions by the ratio of the cleaning solvent input to the
total cleaning and paint solvent input.
G-9
-------
The VOC paint solvent associated with the nonvolatile matter
in as -applied paint comes from both the purchased paint and
thinning solvent added at the plant , The amount from the
purchased paint is estimated from the ratio of solvent to
nonvolatile matter in the purchased paint. The amount of
additional thinning solvent is estimated based on knowledge of
the dilution ratio and the VOC weight fraction of the purchased
paint. This procedure for estimating the amount of paint solvent
originally associated with the nonvolatiles in the waste stream
(P) is expressed mathematically in Equation 4.
P = (W) x (1 - Xw) x (Rp) x (1 + Rp/Xp) (4)
where :
Rp = ratio of VOC to nonvolatile matter in the purchased
paint, Ib vOC/lb nonvolatile matter
Xp = VOC weight fraction of purchased paint, Ib VOC/lb paint
RT = weight ratio of thinning VOC solvent added to a pound
of purchased paint, Ib VOC/lb paint
6.2.2.2 Case Studies. Table G-l summarizes the use of
cleaning solvent at three plants that conduct once -through
cleaning according to the procedure shown in Figure 6-2.^"14
Each plant cleaned two spray guns. One plant has siphon- feed
guns. About 1 pound of solvent is used for cleaning a siphon-
feed gun, about the same as for the siphon- feed example described
in Section G.2.1 and Figure G-l. The other two plants have
pressure -feed systems with 5 ft and 107 ft of hose, respectively.
Usage there is higher and is a function of the length and' area of
hose, although not in direct proportion. The operating
procedures and the calculations used to develop these usage
factors for Plant L are shown in Appendix H.
G-10
-------
TABLE G-l. SUMMARY OF CLEANING SOLVENT USAGE AT PLANTS
THAT CONDUCT ONCE-THROUGH MANUAL CLEANIN
r5-l<
Plant
J
K
L
No. of guns
inUOS
2
2
2
No. of
cleaning
cycles per
year
1,476
2,040
796
Hose length,
ft
0"
5b
107b
Area
cleaned,
ft2/cycle
0.9
N/A
5.5
Cleaning solvent usage
Ib/yr
1,459
3,781
12,292
Ib/cycle
0.99
1.85
15.4
Ib/ft2
1.1
N/A
2.8
f^This plant uses aiphon-feed gun.
"The hose O.D. is 0.25 in.; ID is 0.1968 in.
N/A = not available.
Table G-2 summarizes the spent solvent parameters for the
only plant that provided sufficient information to allow
estimation of the solvent contribution from the paint.5"7 The
plant maintains segregated waste records for this UOS, and an
analysis was made of a small sample of the waste (18.3 percent
paint contaminants). The plant uses several paints. Data were
available for only one of the several paints used in the plant.
According to the MSDS, its VOC content is between 50 and
70 percent; the remaining 30 to 50 percent is nonvolatiles. A
nonvolatiles content of 40 percent was used for estimating the
contribution of paint solvent in the waste. The plant also adds
0.022 Ib of virgin thinning solvent per Ib of paint.
Emissions at this plant were calculated using equations 2
through 4 as described in Appendix H. As shown in Table G-2 (and
in Appendix H), the emissions for the paint spray gun were
calculated to be 2,370 Ib/yr. Normalized emission factors for
this case are 3.0 Ib/cleaning cycle and 0.5 Ib/ft2 of area
cleaned. The emissions per cleaning cycle are higher than those
for the uncontrolled example presented in Section G.2.1, perhaps
because this is a pressure-feed gun system. However, the
emissions per unit area cleaned may be similar or even lower (the
area cleaned was not reported for the uncontrolled example, but
it may be similar to that for Plant J). Also, because spent
G-ll
-------
solvent is collected, the emissions for this plant are only
25 percent of usage rather than 100 percent. Appendix H presents
the calculations for this case study.
TABLE G-2. SUMMARY OF SPENT SOLVENT COLLECTION AND
EMISSIONS FROM CLEANING THE PAINT SPRAY GUN AT PLANT L'5"7- -
Parameter
Spent solvent collected
Total, Ib/yr
VOC, Ib/yr
Paint nonvolatiles, Ib/yr
Associated paint solvent, Ib VOC/yr
Emissions
Ib/yr
Ib/cycle
lb/ft2
Quantity
16,820
13,742
3,078
4,784
2,370
3.
0.
0
5
G.2.3 Recirculating Cleaning Solvent (Subcateaorv No. 3)
A second alternative that clearly reduces usage and may
reduce gun cleaning emissions is to recirculate solvent for
additional gun cleanings. As shown in Figure G-3, this results
in a simpler UOS than that for subcategory No. 2. The steps up
to cleaning the gun are the same for both. In this case,
however, spent solvent is returned to the solvent vessel (either
the solvent bucket, if used, or directly to a solvent tank).
This recirculation can be accomplished by aiming the gun to spray
the spent solvent directly into the solvent vessel or into a
basin that drains into the container.
The material balance for this subcategory is the same as for
subcategory No. 2 (Equation 2). However, there are fewer
emission locations, which may result in lower emissions. Because
of recirculation within the UOS, this subcategory also has the
potential to achieve significantly lower usage and waste
generation. Although this cleaning procedure was identified at
one of the plants that responded to the EPA survey, the reported
data were inadequate to quantify the material balance.
G.2.4 Cleaning With Commercial Gun Washers (Subcateaory No. 4)
G-12
-------
0
I
H
u>
(fugitive emission)
V2
(fugitive emission)
A
(fugitive emission
"3 from spraying ^5
(fugitive emission) spent solvent) (fugitive emission)
I
Si
(cleaning
solvent
input)
*NOTE: Thinning solvent associated with the paint nonvolatile matter removed from the hose and gun while cleaning must also
be included in the material balance.
Figure G-3. Schematic of manual spray gun cleaning unit operation system
with recirculated solvent.
-------
Equipment that is designed specifically for cleaning spray
guns, sprays cups/pots from siphon- or gravity-feed systems, and
even flexible paint hoses is available from a number of
manufacturers. Such equipment is typically referred to as a. gun
washer. Most manufacturers produce an enclosed cabinet in which
solvent is both sprayed over the gun and cup and drawn through
the gun. Hose flushing capabilities are often options that
consist of appropriate fittings on the outside of the gun washer
to which a hose can be connected. At least one company makes an
open gun washer. Figures G-4 and G-5 present diagrams of closed
and open gun washers, respectively.4'15'16
The schematic for a gun washer UOS is shown in Figure G-6.
The material balance is the same as that for subcategory No. 2
(Equation 2) . All gun washers recirculate solvent, as in
Subcategory No. 3, but because the recirculation occurs inside
the gun washer, the steps are not diagramed in Figure G-6. Rags
are illustrated in Figure G-6 because they may be used to wipe
the exterior of a hose. All other exterior surfaces are cleaned
within the gun washer.
Because gun washers recirculate solvent, they can achieve
significant usage and emissions reductions relative to
uncontrolled cleaning (subcategory No. 1). One manufacturer
claims usage reductions of 80 to 90 percent, and another
calculates payback time for automotive refinishing shops based on
"a very conservative estimate" of about 50 percent.4'15
very little case data on washers was available. One
automobile engine manufacturing plant reported that spent solvent
collection from a gun washer was 80 percent of the annual usage
(emissions were only 20 percent). This value was based on
judgement, not measurement, and they believe it is conservatively
low.17'18 However, it does not account for paint solvent
collected in the waste. Also, the plant was unable to provide
the nonvolatile matter content of the waste, the number of
cleaning cycles, or the area cleaned. These data are critical to
calculating the amount of paint solvent in the waste, emissions,
G-14
-------
o
H
in
Figure G-4. Picture and schematic of typical closed gun cleaner.'
-------
Figure G-5. Typical open gun cleaner.
16
G-16
-------
I (fugitive
emission)
V2 (fugitive
emission)
V3 (fugitive
emission)
V4 (fugitive
emission)
Sl
(cleaning
solvent
input)
4
I
I
Solvent storage
lank
A
Gun
washer*
i
1
**^^*
Rags
«X" *^M
-^^
\
r
^
r
*~~
A
T
1
1
Spent solvent
storage tank
h.
1 ^
W (waste)
*NOTE: Thinning solvent associated with the paint nonvolatile matter removed from the hose and gun while cleaning must also
be included in the material balance.
Figure G-6. Schematic of gun washer unit operation system.
-------
and normalized usage and emissions factors. Consequently, the
solvent efficiency for gun washers cannot be compared to the
other subcategories.
In 1990, an emissions test of gun washers was commissioned
by Safety-Kleen, using a protocol developed by SCAQMD. According
to the test report, one clean gun and paint cup were used in each
test run, BASF lacquer thinner was used as the solvent, and
manufacturer-recommended operating procedures were followed. The
test did not examine hose cleaning.19
Surprisingly, the test results showed higher emissions from
the closed gun washers than from the open units. These results
were disputed by one manufacturer (of closed units) because, he
reported, outdated closed models were tested, and the operating
procedures used for the open unit were significantly simpler than
recommended by the manufacturer.20 The potential improvement of
newer closed models or of using different operating procedures
for the open models are unknown. The most conservative
(i.e., highest) estimate, however would use the existing data on
closed gun washers. The average active losses (emissions during
the cleaning cycle) for these units were about 32 g/cycle
(0.07 lb/cycle), and passive losses (emissions while the unit is
idle) were about 2.8 g/hr (0.0062 Ib/hr).1'9
Based on these emission factors, the emissions from the
uncontrolled plant described in Section G.2.1 could be reduced
from 460 to 90 Ib/yr (0.07 x 500 + 0.0062 x 8,760 x 0.99 = 90); a
reduction of 80 percent. The relative efficiency of a gun washer
and the procedures for subcategory Nos. 2 and 3 cannot be
determined without additional data.
G.3 CLEANING AUTOMATIC PAINT SPRAY SYSTEMS
Automatic spray systems are used in plants with repetitive
painting requirements, particularly assembly line work. Just as
when cleaning a manual gun, solvent may be used on a once-through
basis (subcategory No. 5) or recirculated (subcategory No. 6).
Descriptions of both subcategories are presented below. Also
presented are case study data to illustrate the use of the
G-18
-------
material balance for subcategory No. 6. No data are available
for subcategory No. 5.
G.3.1 Description of UPS Subcateaory Nos. 5 and__6.
The UOS diagrams are shown in Figures G-7 and G-8. The
primary difference between the cleaning procedures in these UOS's
and those in Figures 4-2 and 4-3 is that the hose and part of the
gun are purged with solvent that is not discharged through the
nozzle. Rather, it is forced through a tube attached to the base
of the gun and either collected for disposal or recirculated to
the feed storage tank. Only a small, short burst exits the gun
nozzle, and it evaporates. Minor fugitive losses may occur from
fittings and during transfer to storage tanks. Solvent may also
be used to clean the exterior of the guns and hoses, if they are
not covered. Except for the number of emission locations, the
material balance shown in Equation 2 for cleaning manual guns
also applies to these subcategories.
G.3.2 Case Studies
Data from five plants (all of the same metal furniture
company) were used to normalize usage and emission factors for
cleaning automated spray guns for subcategory No. 6. Four plants
in the automotive industry provided additional support data.
Several assumptions are included in this analysis. First,
material balances for calculating emissions for these plants are
based on the assumption that all of the reported data are for
cleaning automatic equipment. This assumption was necessary
because the plant cleans both automatic and manual guns, but the
amount of solvent used for each purpose is not monitored.
However, it was reported that "automatic systems predominate" at
each plant. A second, related assumption is that all of the
reported cleaning cycles and areas cleaned are for automatic
equipment. This assumption was necessary because the plants
identified only the totals, not the amount for each type of gun.
Finally, the nonvolatile matter content of the paint as-applied
G-19
-------
(fugitive
emission)
V.2.
(fugitive
emission)
V3
(fugitive
emission)
V4
(fugitive
emission
from solvent
discharged
through nozzle)
(fugitive
emission)
Vg
(fugitive
emission)
Q
K>
O
sl.
solvent
input)
^
W
A
_ i .
i
i
Cnlvpnt
drum
or
tank
I
i
[
Paint hose
\
1
k
Spray gun4
K
L»a^i
\
X
£
\
i
i
i
i
f
/
^
4
i
Qn^nt
solvent
drum
or
W (waste)
*NOTE: Thinning solvent associated with the paint nonvolatile matter removed from the hose and gun while cleaning
must also be included in the material balance.
Figure G-7. Schematic of automatic spray gun cleaning unit operation system with
11 once-through" solvent use and collection of spent solvent (subcategory No. 5) .
-------
(fugitive
emission)
V.2.
(fugitive
emission)
V3
(fugitive
emission)
V.4.
(fugitive
emission
from solvent
discharged
\e
(fugitive
through nozzle) emission)
Si
(cleaning
solvent
input)
I
to
H
Solvent
drum
or
tank
Paint hose
Spray gun"
_J
Recirculating solvent
W (waste)
*NOTE: Thinning solvent associated with the paint nonvolatile matter removed from the hose and gun while cleaning must also
be included in the material balance.
Figure G-8.
Schematic of automatic spray gun cleaning unit operation system with
recirculating solvent (subcategory No. 6).
-------
was assumed in order to estimate the amount of paint solvent
collected in the waste solvent.
G.3.2.1 Cleaning Solvent Usage. As shown in Table G-3,
each of the five metal furniture plants reported the total number
2T 7 ft
of cleaning cycles and the total cleaning solvent usage. A
Assuming all of the usage and cleaning cycles are for cleaning
automated equipment, the usage factors range from about 1 to 9 Ib
per cleaning cycle. This range is within the range of usage
factors for manual cleaning noted above.
The five plants also reported the total surface area cleaned
during each cycle. Table G-3 shows the usage factors range from
nearly zero to more than 6 lb/ft2 cleaned.21"27 The reason is
not clear, but perhaps because long lines may be purged
simultaneously with the guns at two of the plants (the length of
hose/line was not reported).28 These values differ by a wider
range than those for the manual cleaning in Section G.2.2.
These results suggest it is unlikely that combining manual
and automatic gun cleaning significantly affected the usage
factors for automatic cleaning. Assuming that the data industry
provided are correct, these results would suggest that neither
the number of cleaning cycles nor the area cleaned characterize
usage by themselves. Other factors such as worker practices or
the amount of paint that must be removed (i.e., because paints
have different nonvolatile matter contents or because nonvolatile
matter settled in the painting equipment) may also be important.
a. Collected Waste Solvent. According to each of the five
metal furniture plants, the cleaning solvent is recirculated
until the paint contaminants level in the collecting container
reaches 33 percent. The spent solvent is then disposed. Four of
the plants indicated that the amount of solvent in the collected
waste is equal to 80 to 90 percent of the fresh cleaning solvent
feed; the fifth plant indicated the amount is only about
50 percent.21"24 The basis for these values (either records or
estimates) is uncertain.
G-22
-------
TABLE G-3. SUMMARY OF CLEANING SPRAY GUNS AT METAL FURNITURE PLANTS21"28
Plant
M
N
0
P
Q
Number
of
cleaning
cycles per
year
213,642
330,000
91,200
135,065
16,250
Area
cleaned,
fAcycle
1.47
0.78
16.9
238
1.45
Cleaning solvent usage
ton/yr
997
198
133
295
42
Ib/cycle
9.33
1.20
2.92
4.36
5.18
Ib/ft2
635
1.54
0.17
0.02
3.57
Paint
solvent,
ton/yr"
606
134
51
196
25
Collected Solvent
ton/yr
820
182
69
265
34
% of all
usage
51
55
37
54
50
Emissions
ton/yr
782
150
115
225
33
Ib/cycle
7.32
0.91
2.52
3.34
4.10
Ib/ft2
4.98
1.17
0.15
0.01
2.82
o
I
to
u>
"Based on assumption that paint is 40 percent solids and 60 percent organic solvent (all VOC).
-------
The plants did not determine the amount of paint solvent in
the waste solvent, and they did not provide the nonvolatile
matter content of the paint. Thus, it was assumed the paint as
applied is 40 percent nonvolatiles. Using Equation 4 with
Itp = 0, the paint solvent in the waste was estimated to range
from 25 to 600'tons/yr, as shown in Table G-3. When these valves
were subtracted from the waste solvent, the cleaning solvent in
the waste ranges from 37 to 55 percent of the total cleaning
feed.
Similar information was obtained from four automotive
assembly plants. These plants, which use solvent on a once-
through basis, reported waste solvent collection to be about
85 percent of usage.29'30 The plants'based these estimates on
actual waste disposal records corrected for contaminant levels
and on total usage rates corrected for estimated amounts used in
booth cleaning. The amount of solvent contributed by the paint
in the gun was not reported. It could not be estimated because
the amount of contaminants in the waste was not reported. The
actual solvent in the collected waste, then, is unknown, but
certainly is less than the reported 85 percent.
G.3.2.3 Emissions. Based on the data and assumptions
discussed above, the emissions factors for the metal furniture
plants range from about 1 to 7 Ib/cleaning cycle and nearly zero
to 5 lb/ft2. No data are available for direct comparisons with
subcategory No. 3 (manual cleaning with recirculated solvent) or
subcategory No. 5 (automatic cleaning with once-through solvent).
However, the values from Section G.2.2 for Plant L, which cleans
manual guns with once-through solvent, were well within these
ranges. These data suggest there may be little difference in
emissions between subcategory Nos. 2, 3, 5, and 6.
The official position of the American Automobile
Manufacturers Association (AAMA) (formerly the Motor Vehicle
Manufacturers Association [MVMA]) is that emissions from cleaning
automatic robotic and reciprocating spray guns (and hoses between
G-24
-------
color changers and the guns) are equal to about 10 percent of the
solvent used.31 The basis for this statement is unclear.
A. AUTOMATIC VS. MANUAL CLEANING
Two automotive assembly plants reported recently switching
from extensive use of manual guns to automatic equipment. They
indicated that solvent collection rates were only 28 and
46 percent of the usage for the manual cleaning.32 The rates
were low because the painters were purging the manual guns into
the wastewater system. Since increasing their level of
automation, one plant increased its waste collection from 46 to
87 percent of usage.30 Usage was not reported, but assuming it
did not change significantly, emissions must have been reduced.
The number of cleaning cycles and area cleaned also were not
reported, which precluded development of normalized usage and
emissions factors for comparison of manual and automatic
cleaning.
G.5 SPRAY GUN CLEANING UOS COSTS
This section presents estimated accounting system costs and
cleaning costs under spray gun cleaning UOS subcategories 1 and 4
(i.e., uncontrolled and in an enclosed commercial gun washer) for
Plant I. The accounting system costs are based on assumptions
about recordkeeping requirements for Plant I and accounting
system cost data presented in Chapter 5. The cleaning costs are
also based on the operating data described in this appendix for
Plant I. This is the only plant for which sufficient data are
available to develop the cost analyses for both subcategories.
All costs are in second quarter 1992 dollars. The accounting
costs are shown in Table G-4, and cleaning costs for both
subcategories are shown in Table G-5.
G.5.1 Accounting System Costs
The accounting system costs are assumed to be equal
regardless of the cleaning procedure that is used. Purchased
equipment costs are based on the average of costs for plants C,
E, and G. Recordkeeping was assumed to require 5 minutes per
cleaning cycle, and an identical amount of time was assumed for
G-25
-------
TABLE G-4. SOLVENT ACCOUNTING SYSTEM COSTS
FOR SPRAY GUN UOS AT PLANT I
Costing parameters
A.
B.
C.
D.
Total capital investment, $
1". Purchased equipment costsa
2 . Installation"
3 . Initial training3
Direct annual costs, $/yr
1. Operating labor
-recording0
-data entry/analysis0
2. Maintenance labor and materials"
Indirect annual costs, $/yr
1 . Overhead6
2 . Administrative charges
3 . Property tax
4 . Insurance
5 . Capital recovery
Total annual cost
Costs
1,600
0
2,077
500
500
500
1,500
900
41
21
21
347
1,330
2,830
aAverage of purchased equipment and training costs for
Plants C, E, and G (assumes existing computer equipment can
be used).
^Assumed to be included in the purchased equipment cost.
^Assuming 5 min/cycle, $12/hr.
"Assuming equal to recording operating labor.
eEqual to 60 percent of labor and maintenance materials
costs.
G-26
-------
TABLE G-5. COSTS FOR CLEANING SPRAY GUNS AT PLANT I
A.
B.
C.
D.
E.
Total capital investment, $
1 . equipment
2. taxes & freight
3. installation
Annual costs for cleaning
1. Direct annual costs, $/yr
a. cleaning solvent
b. operator labor
c. supervisory labor
d. maintenance labor
e. maintenance materials
f . waste disposal
2. Indirect annual costs, $/yr
a. overhead
b. properly taxes, insurance,
and administrative charges
c. capital recovery
Accounting system cost, Syr8
Total annual cost, $/yr
Savings achieved with control
alternative, $/yr
Subcategory
No.l
0
0
o
0
247
1,000
ISO
0
0
0
690
0
_2
2,087
2,830
4,917
N/A
Subcategory
No.4
2,000
160
^00
2,360
49
200
30
104
104
21
263
94
384
1,249
2,830
4,079
838
N/A = Not applicable.
*See Table 5-3 for derivation of accounting costs.
G-27
-------
data entry and analysis. Indirect annual costs are based on the
procedures described above. The resulting total annual cost is
about $2,800.
1. Costs for Uncontrolled Cleaning
Uncontrolled costs consist of solvent and labor costs. As
noted in Section G.2.1, Plant I uses 464 Ib/yr of cleaning
solvent for cleaning two guns. The plant also reported
500 cleaning cycles per year, a solvent unit cost of $3.86/gal,
and a VOC content of 7.26 lb/gal.33'34 The operator labor time
needed to clean the guns was assumed to be 10 minutes per
cleaning cycle.35'36 The operator wage rate was assumed to be
$l2/hr. Based on these data, the solvent cost is $247/yr, and
the operator labor cost is $l,000/yr. Based on OAQPS cost
factors, supervisory labor costs were estimated to be equal to
15 percent of the operator labor costs, and overhead was
estimated to be equal to 60 percent of all labor and maintenance
materials costs.37'38 As shown in. Table G-5, the resulting total
annual cost is about $2,100/yr.
G.5.3 Gun Washer Costs
List prices for enclosed gun washers range from about $800
to $2,500. This analysis uses a cost of $2,000, which is the
cost for the most popular gun washers.35'36 Based on OAQPS cost
factors, taxes and freight were estimated to be equal to eight
percent of the equipment cost.39 According to one gun washer
manufacturer, the installation cost is equal to 10 percent of the
equipment cost.35
Assuming solvent usage is reduced by 80 percent (to
93 Ib/yr), the solvent cost would be reduced to $49/yr.
According to gun washer manufacturers, labor requirements to set
up and operate the gun washer are about 2 minutes per cleaning
cycle (time to allow the guns and other parts to drain are not
included}.35'36 One gun washer manufacturer estimated weekly
cleaning of the equipment takes about 10 minutes/wk; it was
assumed that this time is sufficient for all maintenance labor
requirements.35 Thus, operator labor costs are reduced to
G-28
-------
$200/yr, supervisory labor costs are reduced to $30/yr, and
maintenance labor costs are about $104/wk.
The amount of spent solvent collected for waste disposal was
assumed to be equal to 50 percent of the usage (i.e.,
0.5 x 93 Ib/yr). and the density was assumed to be 8 Ib/gal (a
little higher than the density of the virgin solvent). According
to the plant, waste disposal costs are $198/55-gal drum.34
Based on OAQPS cost factors, costs for maintenance materials
(i.e., miscellaneous items need to keep the gun washer in working
order) were estimated to be equal to the maintenance labor costs;
overhead costs were estimated to be equal to 60 percent of all
labor and maintenance material costs; and property taxes,
insurance, and administrative costs were estimated to be equal to
four percent of the TCI.38'40 Capital recovery costs were
estimated to be equal to 16.275 percent of the TCI, based on an
assumed equipment life of 10 years and a marginal rate of return
of 10 percent. As shown in Table G-5, the resulting total annual
cost is about $1,250.
2. Comparison of Costs
This analysis shows annual costs for spray gun cleaning at
Plant I could be reduced by about 17 percent by installing a gun
washer. Assuming emissions are reduced by 90 percent (to be
consistent with the above usage and waste assumptions), the cost
effectiveness of this control alternative is a savings of about
$2.00/lb of VOC ($4,000/ton VOC). Plants with a higher cleaning
frequency may achieve even greater savings.
B. REFERENCES FOR APPENDIX G
1. Letters and attachments from Kasper, T., Westinghouse
Electric Corporation, to Jordan, B. EPA/ESD. February 5
and June 16, 1992. Response to Section 114 information
request.
2. Telecon. D. Randall, MRI, with T. Kasper, Westinghouse
Electric Corporation. February 5 and March 1, 1993. Spray
gun cleaning procedures.
G-29
-------
3. U. S. Environmental Protection Agency. Automobile
Refinishing Control Techniques Guideline. Research Triangle
Park, NC. Draft. September 27, 1991. p. 4-9.
4. Letter and attachments from Muir, G., Graco, Inc., to
Randall, D., MRI. February 5, 1993. Cost and operation of
gun washers.
5. Letter and attachments from O'Reilly, B., Westinghouse
Electric Corporation, to Jordan, B., EPA/ESD. August 15,
1991. Response to Section 114 information request.
6. Letter and attachments from O'Reilly, B., Westinghouse
Electric Corporation, to Serageldin, M., EPA/CPB. June 26,
1992. Response to Section 114 information request.
7. Telecon. D. Randall, MRI, with B. O'Reilly, Westinghouse
Electric Corporation. March 24, March 26, and April 14,
1993. Spray gun cleaning procedures.
8. Letter and attachments from Self, T., Westinghouse Electric
Corporation, to Jordan, B., EPA/ESD. August, 1991.
Response to Section 114 information request.
9. Letter and attachments from Self, T., Westinghouse Electric
Corporation, to Schmidtke, K., MRI. January 27, 1992.
Followup to Section 114 information request.
10. Letter and attachments from Domrese, J., Westinghouse
Electric Corporation, to Serageldin, M., EPA/CPB. June 15,
1992. Followup to Section 114 information request.
11. Telecon. D. Randall, MRI, with J. Domrese, Westinghouse
Electric Corporation. March 8, 1993. Spray gun cleaning
procedures.
12. Letters and attachments from Stephens, R., Square D Company,
to Jordan, B., EPA/ESD. July 29, 1991, and January 17,
1992. Response to Section 114 information request.
13. Letter and attachments from Stephens, R., Square D Company,
to Wyatt, S., EPA/CPB. June 3, 1992. Followup to
Section 114 information request.
14. Telecon. D. Randall, MRI, with R. Stephens, Square D
Company. February 19 and April 5, 1993. Spray gun cleaning
procedures.
15. Letter and attachments from Robb, R., Herkules Equipment
Corporation, to Serageldin, M., EPA/CPB. March 23, 1993.
Gun washer design, operation, and costs.
G-30
-------
16. Promotional literature from Safety-Kleen Corporation.
17. Letter and attachments from Praschan, E., Motor Vehicle
Manufacturers Association to Serageldin, M., EPA/CPB.
February 19, 1992. Plant No. 10 response to survey
questionnaire.
18. Telecon. D. Randall, MRI, with J. Baguzis, Ford Motor
Company. February 16, 1993. Spray gun cleaning procedures
with gun washer at MVMA plant No. 10.
19. ENSR Consulting and Engineering. Comparison of Solvent
Emissions From Two Types of Spray Gun Cleaning Systems.
Prepared for Safety-Kleen Corporation. ENSR Document
No. 5831-005-800. March, 1990.
20. Letter from Robb, R., Herkules Equipment Corporation, to
South Coast Air Quality Management District. April 25,
1990. Comments on gun washer emission test.
21. Letter and attachments from Herman, K., Steelcase, Inc., to
Jordan, B., EPA/ESD. February 4, 1992. Response to
Section 114 information request for Chair plant.
22. Letter and attachments from Herman, K., Steelcase, Inc., to
Jordan, B., EPA/ESD. April 15, 1992. Response to
Section 114 information request for Panel and Systems II
plants.
23. Letter and attachments from Herman, K., Steelcase, Inc., to
Jordan, B., EPA/ESD. April 1992. Response to Section 114
information request for Systems I plant.
24. Letter and attachments from Herman, K., Steelcase, Inc., to
Jordan, B., EPA/ESD. June 25, 1992. Response to
Section 114 information request for File plant.
25. Letter and attachments from Herman, K., Steelcase, Inc., to
Jordan, B., EPA/ESD. September 18, 1992. Followup response
to Section 114 information request for Panel and Systems I
plants.
26. Letter and attachments from Herman, K., Steelcase, Inc., to
Jordan, B., EPA/ESD. October 5, 1992. Followup response to
Section 114 information request for File and Systems II
plants.
27. Letter and attachments from Herman, K., Steelcase, Inc., to
Jordan, B., EPA/ESD. October 15, 1992. Followup response
to Section 114 information request for Chair plant.
G-31
-------
28. Telecon. D. Randall, MRI, with K. Herman, Steelcase, Inc.
February 1 and 16, 1993. Spray gun cleaning procedures at
five Steelcase plants.
29. Reference 18, plant Nos. 2, 3, 4, and 5.
30. Telecon. D. Randall, MRI, with P. Strabbing, Chrysler
Corporation. February 23, March 4, and March 22, 1993.
Spray gun cleaning procedures at Chrysler plants.
31. Letter and attachments from Praschan, E., American
Automobile Manufacturers Association, to Serageldin, M.,
EPA/CPB. January 13, 1993. Descriptions of automatic line
flushing and purging processes.
32. Reference 18, plants Land 6.
33. Letters and attachments from Rasper, T., Westinghouse
Electric Corporation, to Jordan, B., EPA/ESD. February 5
and June 16, 1992. Response to Section 114 information
request.
34. Telecon. D. Randall, MRI, with T. Kasper, Westinghouse
Electric Corporation. February 5 and March l, 1993. Spray
gun cleaning procedures.
35. Letter and attachments from Muir, G., Graco, Inc., to
Randall, D., MRI. February 5, 1993. Cost and operation of
gun washers.
36. Letter and attachments from Robb, R., Herkules Equipment
Corporation, to Serageldin, M. EPA/CPB. March 23, 1993.
Gun washer design, operation, and costs.
37. Office of Air Quality Planning and Standards Control Cost
Manual (4th ed.). U. S. Environmental Protection Agency.
Research Triangle Park, NC. Publication No. EPA 450/3-90-
006. January 1990.
38. Reference 1. p. 2-29.
39. Reference 1. p. 2-22.
40. Reference 1. p. 2-26.
G-32
-------
APPENDIX H.
SPRAY GUN CLEANING PROCEDURES AND
MATERIAL BALANCE CALCULATIONS FOR THE "PAINT
SPRAY GUN" UOS AT CASE STUDY PLANT L
-------
APPENDIX H.
SPRAY GUN CLEANING PROCEDURES AND
MATERIAL BALANCE CALCULATIONS FOR THE "PAINT
SPRAY GUN" UOS AT CASE STUDY PLANT L
This Appendix describes the spray gun cleaning procedures at
case study plant L and presents calculations used for completing
the material balance for the "paint spray gun" UOS at this plant.
The completed UOS diagram is shown in Figure H-l.
H.I CLEANING PROCEDURES
Plant L has two hand-held, pressure-feed paint spray guns
that are purged with xylene. The plant estimated each gun, and
an attached 107-ft paint line, is purged 398 times per year, for
a total of 796 cleaning cycles per year. To purge a gun and
attached paint line, an unspecified amount of xylene is hand
pumped into a 5-gallon pail. The end of the paint line is put in
the pail, and solvent is pumped through the hose and gun. Paint
is not drained from the system before purging with solvent.
instead, discharge from the gun is first directed into a paint
can. When the xylene starts to come through, the painter
redirects the discharge to a waste pail. The waste pail is later
emptied into a 55-gallon waste drum. The exterior of the lines
do not need cleaning. The exterior of the guns may be cleaned
occasionally, but the procedure was not reported.
H.2 MATERIAL BALANCE CALCULATIONS FOR SPRAY GUN UOS
As described in Appendix G, the material balance for the UOS
at this plant is:
vo - vl + + V8 Sl ' W)x(Xw) (1)
where:
V0 = total VOC emissions, Ib/yr
H-l
-------
(fugitive
emission)
W
i
to
V2
(fugitive
emission)
V3
(fugitive
emission)
V4
(fugitive emission
from spent
solvent
sprayed into
the air)
Ys
(fugitive
emission)
Y6.
(fugitive
emission)
V7
(fugitive
emission)
Si = 12.292 Ib/yr
(cleaning solvent input)
V.8.
(fugitive
emission)
W= 16,820 Ib/yr (waste)
Xw = 0.817 IbVOC
Ib waste
(W)x(Xw) = 13,742 Ib VOC/yr
*Note: Up to 4,784 Ib VOC/yr of paint solvent are collected in the cleaning solvent waste.
Figure H-l.
Schematic of spray gun cleaning unit operation system
for case study Plant L.
-------
V-^.-.Vg = emissions from individual activities within the
UOS, Ib/yr
S-^ - total weight of solvent usage, Ib/yr
W = total weight of waste solvent, Ib/yr
X^ = VOC weight fraction of waste solvent, Ib VOC/lb
waste
For this plant, the calculation is complicated by the fact
that the cleaning solvent (xylene) used in the spray gun UOS is
also used in several other UOS's, but only the total usage was
recorded. Because approximately 97 percent of the xylene was
used in the "paint spray gun" UOS and an "epoxy spray gun" UOS,
this analysis assumes all of the xylene was used in these two
UOS's. Another complicating factor is that a portion of the
solvent in the waste came from residual paint in the spray gun
that was carried off with the cleaning solvent (this is referred
to as "paint solvent" in the rest of this Appendix). Thus, to
calculate the cleaning solvent emissions from the spray gun UOS,
the emissions calculated by Equation 1 must be increased by the
amount of collected paint solvent in the waste container.
For this plant, however, the amount of collected paint
solvent is unknown. The plant recorded both W and x^, but the
composition of ,the waste solvent was not determined. In the
absence of this information, it is assumed that the paint solvent
volatility is similar to that of xylene (the cleaning solvent).
Thus, equal proportions of both solvents are assumed to
evaporate.
Adding the paint solvent originally associated with the
nonvolatiles (i.e., paint solids) in the waste as an input allows
Equation 1 to be used to calculate the total cleaning and paint
solvent emissions. (The associated paint solvent is referred to
as the "paint solvent input" in the rest of this appendix.) The
cleaning solvent emissions are calculated by multiplying the
ratio of cleaning solvent input to total solvent input (cleaning
plus paint solvent) by the total emissions. Procedures for
calculating these values are described below.
H-3
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H.2.1 Estimation of Paint Solvent Input
The paint solvent input is calculated using the following
equation that was also presented in Appendix G:
P = (W) x (1-V x (Rp) x (1 + RT/XP) (2)
where :
P = weight of paint solvent associated with the nonvolatile
matter in the waste, Ib VQC/yr
W = total weight of waste solvent, Ib/yr
Xw = VOC weight fraction of waste solvent, Ib VOC/lb waste
Rp = ratio of VOC to nonvolatile matter in the purchased
paint, Ib VOC/lb nonvolatile matter
RT = ratio of thinning VOC solvent to paint matter, Ib
thinning VOC/lb paint
Xp = fraction of VOC in purchased paint, Ib VOC/lb paint
RT/Xp = Ib thinning VOC/lb paint VOC
According to plant records, waste shipments from the paint
spray gun UOS in 1991 were:
W = 16,820 Ib waste/yr
Analysis . of the contents of two waste drums showed the average
VOC content was:
^ = 0.817 Ib VOC/lb waste
The MSDS for the most commonly used paint at Plant L showed
the VOC content was between 50 and 70 percent. The nonvolatile
matter content, therefore, .was between 50 and 30 percent. This
is the only paint for which data were available. Thus, Xp was
assumed to equal 0.6 for all paint used at the plant, and Rp was
assumed to equal 1.5 (i.e., 0.6/0.4 =1.5).
Plant records also showed about 1 gal of xylene per week
(378 Ib/yr) was added to thin 17,415 Ib of paint used during the
year. Thus, Rrp equals 0.0217 for the paint spray gun UOS.
Substituting these data into Equation 2 results in the
following estimate of the amount of paint solvent originally
associated with the nonvolatiles collected in the paint spray gun
UOS waste:
H-4
-------
P = (16,820) x (1-0.817) x (1.5) x (1 + 0.0217/0.6)
= 4,784 lb VOC/yr
Equation 2 is used to estimate the paint solvent input for
the epoxy spray gun UOS. According to plant records, waste
shipments from the epoxy spray gun UOS in 1991 were:
W = 7,915 lb waste/yr
Analysis of the waste showed the VOC content was:
j^ = 0.814 lb VOC/lb waste
No data were available for epoxies. Thus, Xp, Rp, and RT
were assumed to be the same as those noted above for the paints.
Substituting these data into Equation 2 results in the following
estimate of the solvent originally associated with the epoxy
nonvolatiles collected in the epoxy spray gun UOS waste:
PE = (7,915) X (1-0.814) x (1.5) X (1 + 0.0217/0.6)
= 2,288 lb VOC/yr
H.2.2 Estimation of Cleaning Solvent Usage
Purchasing and inventory records show the plant used
2,475 gal of xylene (VOC content of 7.27 Ib/gal) in the paint and
epoxy spray gun UOS's. To determine the amount used in the paint
spray gun UOS, it was assumed that the ratio of usage in the two
UOS's was equal to the ratio of paint solvent inputs for these
UOS's. Thus, the fraction of cleaning solvent used in the paint
spray gun UOS is:
f = 4,784
4,784 + 2,288
= 0.6765
Therefore, the cleaning solvent usage in the paint spray gun
UOS is:
Sp = 0.6765 x 2,475 gal/yr x 7.27 Ib/gal
= 12,172 lb solvent/yr
And, the amount of cleaning solvent used in the epoxy spray
gun UOS is:
SE - (1 - 0.6765) x 2,475 gal/yr x 7.27 Ib/gal
= 5,821 lb solvent/yr
H-5
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H.2.3 Estimation of Cleaning Solvent Emissions
The total solvent input (cleaning and paint solvents) is
given by:
SZ = Sp + SE + Pp + PE (3)
where:
Sx = total solvent input to both the paint spray gun and
epoxy spray gun UOS's, Ib solvent/yr
Substituting values for the variables in Equation 3 yields:
Sz = 12,172 + 5,821 + 4,784 + 2,288
= 25,065 Ib solvent/yr
The total solvent in the waste collected from both UOS's is
given by:
WQ = Wp x X^ + WE x X^yg
= (16,820) x (0.817) + (7,915) x (0.814)
= 20,185 Ib solvent/yr
Using the material balance in Equation 1 over both UOS's
results in the following total emissions:
VQ = 25,065 - 20,185
= 4,880 Ib solvent/yr
The assumptions that the volatilities of the cleaning
solvent and the paint solvents in both UOS's are comparable, and
thus equal portions of each solvent evaporate, are used to
calculate the amount of cleaning solvent that evaporates in the
spray gun UOS (Vc) as follows:
Vc = (VQ) x (Sp/Sj)
= (4,880) x (12,172/25,065)
= 2,370 Ib VOC evaporated/yr
H-6
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TECHNICAL REPORT DATA
(Pteate nod Instruction} an-the reverts before completing)
1. REPORT NO.
EPA-453/R-94-015
3. RECIPIENT'S ACCESSION NO.
4. TITLE AND SUBTITLE
Alternative Control Techniques Document
Industrial Cleaning Solvents
5. REPORT DATE
February 1994
6. PERFORMING ORGANIZATION CODE
'. AUTHORIS)
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Midwest Research Institute
401 Harrison Oaks Boulevard, Suite 350
Gary, North Carolina 27513
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
68-D1-0115
12. SPONSORING AGENCY NAME AND ADDRESS
U.S. Environmental Protection Agency
Emission Standards Division
Office of Air Quality Planning and Standards
Research Triangle Park, NC 27711
13. TYPE OF REPORT AND PERIOD COVERED
Final
14. SPONSORING AGENCY CODE
16. SUPPLEMENTARY NOTES
EPA Work Assignment Manager: Mohamed Serageldin
IB. ABSTRACT
The use of cleaning solvents in industry is a large source
of volatile organic compound (VOC) emissions. The study was
conducted to identify emission reduction and control techniques
that have general application across all industry.
The initial approach, which focused on how the cleaning was
accomplished, was unsuccessful. The requisite data for such
detailed evaluation was unavailable. A second strategy, which
focused on the parts and processes being cleaned, produced more
meaningful data.
The study's conclusions were that most industries must first
quantify how much and where solvents are used for cleaning. With
that information, management is then positioned to influence
improvements. The report recommends that companies establish a
formal accounting system that quantitatively traces where they
use cleaning solvents. It also provides suggestions for action
by management (or State agencies) to use the resulting
information to effect reductions.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS
G. COSATI Fteld/GfOUp
Cleaning Solvents
Volatile Organic Compound Emissions
VOC's
Cleaning Solvents
Solvent Accounting
and Management
Pollution Prevention
VOC's
18. DISTRIBUTION STATEMENT
19. SECURITY CLASS (Tim Report)
Unclassified
21. NO. OF PAGES
20. SECURITY CLASS (Tliitpagfl
Unclassified
22. PRICE
EPA Fern* 2220-1 (R*v. 4-77) PRKVIPUI COITION is OBSOLETE
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