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 ------- 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 ------- 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 ------- 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 BULK RATE POSTAGE & FEES PAID EPA PERMIT NO. G-35 EPA/600/SR-97/032 ------- |