Pacific Southwest, Region 9
Serving: Arizona, California, Hawaii, Nevada, Pacific Islands, Tribal Nations
Auto Repair and Fleet Maintenance Pollution Prevention
Water-Based Parts Washer Systems
Case Study Conversions
Prepared for: U.S. Environmental Protection Agency and
Santa Barbara County Air Pollution Control District
Prepared by: Michael Morris, Katy Wolf
Institute for Research and Technical Assistance's Pollution Prevention Center
December 11, 1998
Summary and Conclusions
SCAQMD Rule 1171 requires a conversion away from mineral spirits to cleaners with 50 grams per liter VOC content or less in repair and maintenance cleaning by January 1, 1999. Most facilities in Southern California will comply with the rule requirements by adopting water-based cleaning systems. Other air districts and states will look to the experience in Southern California to provide guidance in adopting future regulations.
There are a variety of water-based cleaners and cleaning systems available that can satisfy the cleaning requirements of the auto repair and industrial facilities that will be affected by the rule. A number of water-based cleaners with no solvent additives are available and they clean very well. These water-based cleaners perform better if they are heated and all of the systems contain heaters.
Five types of water-based cleaning systems are being offered by vendors. The first type of system, the sink-on-a-drum, is likely to be used most widely. It is a sink with a brush mounted on a drum. Parts are placed in the sink and cleaned by hand. The second type of system, the enzyme cleaning unit, is in the configuration of a sink-on-a-drum. Microbes in the system biodegrade the oil and the advantage of this type of unit is that the bath may last indefinitely without the need for changeout. The third system is an immersion unit with a false sink. Parts can be soaked in this type of unit. The fourth type of system is a spray cabinet which cleans more aggressively than the other types of units. It relies on high pressure spray and a higher temperature to clean the parts. The fifth system type is the ultrasonic unit which also cleans very aggressively. It is most suitable for carburetors, transmissions and fuel injectors.
Facilities in Southern California have been converting to the water-based cleaning systems over the last year. IRTA has assisted many businesses in testing, evaluating and implementing alternative systems. This report presents seven case studies that describe the conversion choices of various different types of facilities with a range of cleaning activities. These facilities converted to all five of the different water-based system types--sink-on-a-drum, immersion unit, enzyme system, spray cabinet and ultrasonic unit. This report also includes a cost comparison for each case study facility. In all cases, the cost to the facility for using the water-based cleaning system is lower than the cost of using the mineral spirits system. In some cases, the reason the cost is lower is that the water-based cleaners require changeout less frequently than the mineral spirits. In other cases, where the facilities have purchased spray cabinets or ultrasonic units, the cost is lower because of the labor savings from use of the automated systems.
About 40,000 cleaning units in the South Coast Basin have traditionally used mineral spirits. Some 25,000 of these units are in auto repair facilities and 15,000 are in industrial facilities. The case studies presented here should be useful in providing guidance to other facilities in selecting an appropriate water-based system.
The water-based cleaners are better than solvents from an overall human health and environmental standpoint. They reduce worker exposure and exposure to the surrounding community. They reduce smog formation. Finally, the case studies presented here show that the water systems provide a cost advantage to the users.