United States
Environmental Protection
Agency
National Risk Management
Research Laboratory
Cincinnati, OH 45268
Research and Development
EPA/600/SR-97/032
March 1997
Project Summary
Evaluation of Alternatives to
Chlorinated Solvents for Metal
Cleaning
Karen B. Thomas and Michael Eljenbecker
The Massachusetts Toxics Use Re-
duction Institute (TURI) was funded by
the Environmental Protection Agency
to perform research to support the
EPA's 33/50 Program, a voluntary pol-
lution prevention program to reduce
national releases and offsite transfers
of 17 toxic chemicals. The research
project Investigated alternatives to chlo-
rinated solvents used for metal
degreasing at three companies. Trie re-
sults reported for one company docu-
ment a situation where the conversion
to an aqueous cleaning system had
already been implemented. Those for a
second company provide real-time in-
formation about the conversion from
an intermediate solvent to an aqueous
system. Results for the third company
contribute information about alterna-
tives that must be applicable to a vari-
ety of substrates and configurations.
Testing of the alternatives was con-
ducted both at the companies and at
the TURI's Surface Cleaning Labora-
tory located at the University of Massa-
chusetts Lowell, Lowell, MA. In addi-
tion to the technical evaluations, the
project evaluated financial and envi-
ronmental impacts of the alternative
systems;. For the financial analyses, the
Total Cost Assessment methodology
includes many important environmen-
tal costs not typically included in a
financial analysis. A substitution analy-
sis methodology that provides qualita-
tive results was developed and used to
evaluate the environmental, occupa-
tional, and public health effects of the
alternative cleaning processes.
This Project Summary was developed
by the National Risk Management Re-
search Laboratory, Cincinnati, OH, to
announce key findings of the research
project that is fully documented in a
separate report of the same title (see
Project Report ordering information at
back.)
Introduction
Cleaning and degreasing of metal parts
in the metal finishing and metal working
industries have traditionally been accom-
plished by the use of chlorinated solvents
in vapor degreasers or immersion sys-
tems. In this context, cleaning and
degreasing is, simply, the removal of con-
tamination from the metal surface. This
function is necessary for successful part
performance in subsequent operations
(e.g., plating or welding) or is desirable
aesthetically. The chlorinated solvents
most commonly used for metal cleaning
include: 1,1,1-trichloroethane (1.1,1-TCA),
trichloroethylene (TCE), perchloroethylene
(PERC), dichloromethane (methylene chlo-
ride or METH), and chlorofluorocarbons.
Chlorinated solvents are effective clean-
ers and, in the past, have been consid-
ered "safe" to workers because they are
nonflammable.
Due to concern over the ozone layer,
photochemical smog, and worker health,
increasingly strict environmental regula-
tions have been promulgated on the use
of chlorinated solvents. The result has
been higher costs associated with the pur-
chase and disposal of chlorinated solvents.
Traditional chlorinated solvent cleaning is
becoming a process of the past. For many
companies, however, changing from a
proven process to a new technology is a
difficult task. Many alternatives presented
as "perfect" solutions are found to be inef-
fective cleaners, too expensive, or to
present safety hazards. A careful evalua-
tion of the options can help in selecting
the most cost effective and technically fea-
sible solution without compromising worker
health and safety or environmental pro-
tection.
Printed on Recycled Paper
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the new process and necessitate further
evaluation following installation. An eco-
nomic evaluation of a technically proven
chemical or process provides valuable in-
formation affecting the decision to imple-
ment or not. The results of the financial
assessment further inform the decision to
adopt or not. However, technical and fi-
nancial information combined is not the
final word in decision making. Further
evaluation is required to assess the envi-
ronmental, health, and safety issues in-
volved with the chemicals and processes.
While the technical and cost assessments
are not simple, the environmental, health,
and safety assessment, called substitu-
tion analysis, is perhaps the most difficult
because there is no generally agreed-on
and reliable method for evaluating the en-
vironmental and worker health and safety
risk of alternatives.
In using the three evaluative steps de-
scribed above, it is important to remem-
ber that each project and facility may have
different priorities for making decisions
about whether to implement a particular
technology. This was clearly demonstrated
in this project as the participating compa-
nies had different motives for seeking sub-
stitute technologies. This in turn, dictated
which evaluative step was most important
to them and indicates that the results of
any one of the three can be the driving
factor in a decision. Despite the emphasis
placed on one evaluative step on a given
project, all three aspects must be evalu-
ated so that valuable pieces of informa-
tion are not ignored.
The full report was submitted in fulfill-
ment of Contract No. CR821859-01-0 by
the Massachusetts Toxics Use Reduction
Institute under the sponsorship of the U.S.
Environmental Protection Agency.
•&U.S. GOVERNMENT PRINTING OFFICE: 1997 - 549-001/60136
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Approach
Technical Analysis
During the technical analysis phase, al-
ternatives to the chlorinated solvents were
identified, demonstrated, and evaluated.
The three companies that participated in
this project were Parker Hannifin Corpo-
ration, Market Forge, and Company A, an
electroplating facility. At its Waltham, MA
facility, Parker Hannifin manufactures
pumps for aircraft engines under primary
SIC code 3724. In 1992, the company
began to investigate the replacement of
its two vapor degreasers with an aqueous
cleaning system. The original idea was to
replace both vapor degreasers with one
immersion cleaning system that could sat-
isfy the highest cleanliness needs. After
careful consideration of cleaning needs
and logistics, the company decided to re-
place the vapor degreasers with three
pressure spray washers for frequent re-
mote cleaning following machining, one
ultrasonic unit for the highest cleanliness
needs and one immersion tank for clean-
ing following heat treatment. Parker
Hannifin was chosen to document a situa-
tion where the conversion to aqueous
cleaning had already been made and to
evaluate the new system for its health
and safety, environmental, and financial
performance. A technical evaluation was
- performed~at -TURI's-Surf ace-Gleaning
Laboratory in order to make improvements
to Parker Hannifin's current aqueous clean-
ing process.
Located in Everett, MA, Market Forge
manufactures cooking steamers. Prior to
August 1993, Market Forge used a 1,1,1-
TCA vapor degreasing system to degrease
carbon steel and aluminum boiler parts
before welding. The performance of TCA
was satisfactory, but its use was discon-
tinued because of the labeling require-
ments of the Montreal Protocol. On the
advice of their supplier, Market Forge
switched from TCA to an aliphatic petro-
leum distillate solvent (CAS 64742-88-7).
As soon as the switch was made, the
welders of both the carbon steel and alu-
minum parts began to experience prob-
lems. Market Forge was chosen as a com-
pany in the difficult transition stage. A
technical evaluation was performed at
TURI's Surface Cleaning Laboratory to find
a suitable cleaning process and chemistry
to replace the petroleum distillate. Based
on the information obtained from this
project, Market Forge purchased an Ameri-
can Metal Wash pressure spray washer.
The unit was recently installed and is op-
erating effectively.
Company A is a job-shop electroplating
company located in Massachusetts, By
the nature of the job-shop business, Com-
pany A cannot always predict what types
of metals it will have to clean and thus
requires a flexible cleaning system/ ca-
pable of cleaning many different sub-
strates. Currently the company cleans all
parts in a vapor degreaser using TCE.
Company A was chosen because its situ-
ation is one shared by many job-shop
platers in the northeast, namely, a wide
variety of substrates and contaminants. A
technical assessment identified the follow-
ing alternatives for further study: media
blasting using sodium bicarbonate, plastic
or carbon dioxide, ultrasonic aqueous,
"closed" vapor degreasing, upgrading of
the existing vapor degreaser, Advanced
Vapor Degreasing (AVD™) system, and
supercritical carbon dioxide.
Financial Analysis
For the financial analysis, a total cost.
assessment methodology was used to per-
form financial analyses of the alternative
cleaning processes. Traditional financial
analysis often includes only the costs di-
rectly associated with production, such as
labor and capital and does not include the
costs (and savings) that make pollution
prevention projects profitable. The Total
Cost Assessment methodology used in
=this project is an innovative evaluative tool
that examines many other important costs
associated with an investment including
staff time for environmental reporting,
waste management costs, and permitting
fees.
Substitution Analysis
A substitution analysis methodology was
developed and used to evaluate the envi-
ronmental, occupational, and public health
effects of the alternative cleaning pro-
cesses. The substitution analysis described
is qualitative in nature. It allows the com-
parison of alternatives using many crite-
ria, but a final decision as to the best
alternative must be made by the investi-
gator. Described in worksheet format, this
approach highlights both the areas of con-
cern for alternative processes and areas
where those substitutes clearly are supe-
rior to the current process. The worksheet
will aid the decision maker in making1 in-
formed decisions without overlooking .im-
portant issues.
Conclusions
Some general conclusions were drawn
from the technical evaluation phase in. re-
gard to chemical compatibility/process
specification and "drop-in" replacements.
For chemical compatibility/process speci-
fication, it was concluded that rinsing of a
non-silicated cleaner is not always neces-
sary even when a painting operation fol-
lows, and aqueous immersion cleaning
can be a viable option for steel and alumi-
num substrates prior to nitriding or follow-
ing heat treat operations. With regard to
"drop-in" replacements, it was concluded
that a thorough technical evaluation of so-
called "drop-in" replacements is neces-
sary to avoid unforeseen costs and that
job shops present an unmet challenge to
the vendors of "drop-in" replacements.
Some general conclusions were made
following the financial analysis phase: 1) if
the aqueous systems are replacing older
solvent-based equipment, a savings in
electricity costs may be realized, espe-
cially if air drying is not required; 2) de-
pending on the cooling capacity of the
vapor degreaser, the aqueous systems
may actually use less water; 3) the profit-
ability of an investment in aqueous clean-
ing equipment can be improved by pur-
chasing based on cleaning needs at dif-
ferent stages in the production process;
4) the aggressive taxes on CFCs and
TCA have made aqueous alternatives fea-
sible economically; and 5) the Total Cost
Assessment methodology (P2/Finance
Software) can be used in an iterative pro-
cess to determine costs for unknowns by
-requiring -a - certain net present value;™
These costs can then be assessed to
determine if, for example, a regulatory re-
quirement could be met for a certain cost
rather than actually attempting to place a
value on meeting the regulatory require-
ment.
This project studied three principal
evaluation steps that inform the decision-
making .process for chemical or process
substitution: technical evaluation, economic
evaluation, and environmental, health and
safety evaluation. Each evaluation step is
important in determining the viability of a
substitute technology, in comparison to
the existing technology as well as to other
competing substitute technologies. The
steps can be performed in any order and
their relative importance can vary from
project to project. The technical evalua-
tion of a replacement process for an exist-
ing technically successful process is often
the most important evaluative step. The
success or failure of the technical evalua-
tion determines whether or not the pro-
cess will be evaluated further. Complete
technical evaluation at the lab- and pilot-
scale levels can lead to a smooth transi-
tion into the new process. An incomplete
technical evaluation can lead to unfore-
seen problems with the incorporation of
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Karen B. Thomas and Michael Ellenbecker are with the Toxics Use Reduction
Institute, University of Massachusetts Lowell, Low&ll, MA 01854.
Paul Randall is the EPA Project Officer (see below).
The complete report, entitled "Evaluation of Alternatives to Chlorinated Solvents for
Metal Cleaning," (OrderNo. PB97-147946, Cost: $28.00, subject to change) will
\ be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
National Risk Management Research Laboratory
U.S. Environmental Protection Agency
Cincinnati, OH 45268
\
United States
Environmental Protection Agency
Center for Environmental Research Information
Cincinnati, OH 45268
Official Business
Penalty for Private Use $300
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EPA
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EPA/600/SR-97/032
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