United States National Risk Management

Environmental Protection Research Laboratory

Agency Cincinnati, OH 45268

Research and Development EPA/600/SR-97/032 March 1997

Evaluation of Alternatives to

Chlorinated Solvents for Metal

Cleaning

Project Summary

Karen B. Thomas and Michael Ellenbecker

The Massachusetts Toxics Use Reduction Institute (TURI) was funded by

the Environmental Protection Agency

to perform research to support the

EPA's 33/50 Program, a voluntary pollution prevention program to reduce

national releases and offsite transfers

of 17 toxic chemicals. The research

project investigated alternatives to chlorinated solvents used for metal

degreasing at three companies. The results reported for one company document a situation where the conversion

to an aqueous cleaning system had

already been implemented. Those for a

second company provide real-time information about the conversion from

an intermediate solvent to an aqueous

system. Results for the third company

contribute information about alternatives that must be applicable to a variety of substrates and configurations.

Testing of the alternatives was conducted both at the companies and at

the TURI's Surface Cleaning Laboratory located at the University of Massachusetts Lowell, Lowell, MA. In addition to the technical evaluations, the

project evaluated financial and environmental impacts of the alternative

systems. For the financial analyses, the

Total Cost Assessment methodology

includes many important environmental costs not typically included in a

financial analysis. A substitution analysis methodology that provides qualitative results was developed and used to

evaluate the environmental, occupational, and public health effects of the

alternative cleaning processes.

This Project Summary was developed

by the National Risk Management Research 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 accomplished by the use of chlorinated solvents

in vapor degreasers or immersion systems. In this context, cleaning and

degreasing is, simply, the removal of contamination 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 chloride or METH), and chlorofluorocarbons.

Chlorinated solvents are effective cleaners and, in the past, have been considered "safe" to workers because they are

nonflammable.

Due to concern over the ozone layer,

photochemical smog, and worker health,

increasingly strict environmental regulations have been promulgated on the use

of chlorinated solvents. The result has

been higher costs associated with the purchase 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 ineffective cleaners, too expensive, or to

present safety hazards. A careful evaluation of the options can help in selecting

the most cost effective and technically feasible solution without compromising worker

health and safety or environmental protection.
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Approach

Technical Analysis

During the technical analysis phase, alternatives to the chlorinated solvents were

identified, demonstrated, and evaluated.

The three companies that participated in

this project were Parker Hannifin Corporation, 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 satisfy the highest cleanliness needs. After

careful consideration of cleaning needs

and logistics, the company decided to replace the vapor degreasers with three

pressure spray washers for frequent remote cleaning following machining, one

ultrasonic unit for the highest cleanliness

needs and one immersion tank for cleaning following heat treatment. Parker

Hannifin was chosen to document a situation 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 Surface Cleaning

Laboratory in order to make improvements

to Parker Hannifin's current aqueous cleaning 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 discontinued because of the labeling requirements of the Montreal Protocol. On the

advice of their supplier, Market Forge

switched from TCA to an aliphatic petroleum distillate solvent (CAS 64742-88-7).

As soon as the switch was made, the

welders of both the carbon steel and aluminum parts began to experience problems. Market Forge was chosen as a company 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 American Metal Wash pressure spray washer.

The unit was recently installed and is operating effectively.

Company A is a job-shop electroplating

company located in Massachusetts. By

the nature of the job-shop business, Company A cannot always predict what types

of metals it will have to clean and thus

requires a flexible cleaning system, capable of cleaning many different substrates. Currently the company cleans all

parts in a vapor degreaser using TCE.

Company A was chosen because its situation is one shared by many job-shop

platers in the northeast, namely, a wide

variety of substrates and contaminants. A

technical assessment identified the following 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 (AVDTM) system, and

supercritical carbon dioxide.

Financial Analysis

For the financial analysis, a total cost

assessment methodology was used to perform financial analyses of the alternative

cleaning processes. Traditional financial

analysis often includes only the costs directly 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 environmental, occupational, and public health

effects of the alternative cleaning processes. The substitution analysis described

is qualitative in nature. It allows the comparison of alternatives using many criteria, but a final decision as to the best

alternative must be made by the investigator. Described in worksheet format, this

approach highlights both the areas of concern for alternative processes and areas

where those substitutes clearly are superior to the current process. The worksheet

will aid the decision maker in making informed decisions without overlooking important issues.

Conclusions

Some general conclusions were drawn

from the technical evaluation phase in regard to chemical compatibility/process

specification and "drop-in" replacements.

For chemical compatibility/process specification, it was concluded that rinsing of a

non-silicated cleaner is not always necessary even when a painting operation follows, and aqueous immersion cleaning

can be a viable option for steel and aluminum substrates prior to nitriding or following heat treat operations. With regard to

"drop-in" replacements, it was concluded

that a thorough technical evaluation of socalled "drop-in" replacements is necessary 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, especially if air drying is not required; 2) depending on the cooling capacity of the

vapor degreaser, the aqueous systems

may actually use less water; 3) the profitability of an investment in aqueous cleaning equipment can be improved by purchasing based on cleaning needs at different stages in the production process;

4) the aggressive taxes on CFCs and

TCA have made aqueous alternatives feasible economically; and 5) the Total Cost

Assessment methodology (P2/Finance

Software) can be used in an iterative process 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 requirement could be met for a certain cost

rather than actually attempting to place a

value on meeting the regulatory requirement.

This project studied three principal

evaluation steps that inform the decisionmaking 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 evaluation of a replacement process for an existing technically successful process is often

the most important evaluative step. The

success or failure of the technical evaluation determines whether or not the process will be evaluated further. Complete

technical evaluation at the lab- and pilotscale levels can lead to a smooth transition into the new process. An incomplete

technical evaluation can lead to unforeseen problems with the incorporation of
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the new process and necessitate further

evaluation following installation. An economic evaluation of a technically proven

chemical or process provides valuable information affecting the decision to implement or not. The results of the financial

assessment further inform the decision to

adopt or not. However, technical and financial information combined is not the

final word in decision making. Further

evaluation is required to assess the environmental, health, and safety issues involved with the chemicals and processes.

While the technical and cost assessments

are not simple, the environmental, health,

and safety assessment, called substitution analysis, is perhaps the most difficult

because there is no generally agreed-on

and reliable method for evaluating the environmental and worker health and safety

risk of alternatives.

In using the three evaluative steps described above, it is important to remember 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 companies had different motives for seeking substitute 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 evaluated so that valuable pieces of information are not ignored.

The full report was submitted in fulfillment of Contract No. CR821859-01-0 by

the Massachusetts Toxics Use Reduction

Institute under the sponsorship of the U.S.

Environmental Protection Agency.
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Karen B. Thomas and Michael Ellenbecker are with the Toxics Use Reduction

Institute, University of Massachusetts Lowell, Lowell, MA 01854.

Paul Randall is the EPA Project Officer (see below).

The complete report, entitled "Evaluation of Alternatives to Chlorinated Solvents for

Metal Cleaning," (Order No. 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

EPA/600/SR-97/032

BULK RATE

POSTAGE & FEES PAID

EPA

PERMIT NO. G-35