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Page 3 of 8 methods may actually contribute to the problem. For example, millions of asbestos fibers can be released from drum brakes with these methods: Wiping with a dry rag or brush. Wiping with a wet rag or brush. The water doesn't prevent scattering of much of the asbestos, and when the rag dries or is shaken, asbestos is spread around the garage. Liquid squirt bottles or solvent sprays. The water or solvent under pressure scatters much of the asbestos, and when it dries the asbestos is still all over the surrounding work surfaces. Brake cleaning equipment using these methods with a brush or squirt gun is likely to have the same problems. In fact, measurements from one manufacturer using a liquid spray system showed that over a million fibers can be released near a mechanic's face. Using a specially designed low-pressure spray and properly collecting and disposing of contaminated liquid may prevent some asbestos from spreading around the garage. Some re-circulating wet method equipment uses a solvent to collect brake dust into a tray. If the solvent evaporates from the tray, normal air currents easily lift the asbestos fibers back into the air. Using a garden hose may prevent some brake dust from becoming airborne, but this can easily contaminate the garage floor or other work areas by scattering the asbestos. Using a standard shop vacuum cleaner. A shop vacuum cleaner can spread asbestos about a garage as much as does a compressed air hose (6; using a shop vacuum cleaner raised asbestos concentrations in adjacent bays to levels greater than those found using a compressed air hose). A shop vacuum cleaner filter is not fine enough to collect asbestos fibers. 1 These are the larger fibers measured by common methods for counting asbestos fibers. The very small ones are far more numerous, but can be only be seen with the electron microscope. All of these brake cleaning methods can release enough asbestos into a garage so that an average of over one million of the larger fibers could be breathed each day by workers in that garage. These brake cleaning methods can also cause customers to be exposed, since asbestos from brake work can be spread 75 feet away from the mechanic. When grinding is done to renew used brake block linings, concentrations of up to seven million asbestos fibers per cubic meter can be released. Bevelling new linings can release concentrations of up to 72 million fibers and light grinding of new linings of up to 4.8 million fibers. V. CONTROLLING EXPOSURES NIOSH, OSHA, and EPA recommend that where asbestos exposures cannot be eliminated, they must be controlled to the lowest level possible. Effective containment prevents problems associated with housekeeping and with stirring up settled dust. The best approach is to contain brake dust and prevent its release into a garage. Brake Cleaning Enclosure equipment for brake cleaning is available, which slips easily over the brake assembly and forms a tight seal against the backing plate. A compressed air system can then be used inside this type of enclosure system for good brake cleaning without exposing the brake mechanic or others. Clear plastic walls or windows allow easy visibility of the work being done. Brake dust is sucked into a vacuum cleaner equipped with a special filter called a HEPA or "high-efficiency, particulate air" filter. Only this type of filter can capture the small, invisible asbestos fibers. Non-permeable glove attachments on some equipment allow a mechanic to do work inside the enclosure without getting asbestos on the hands. If glove attachments are available only as an option, this option should be selected. How to Use Enclosure Equipment for Cleaning Drum Brakes Steps for using this type of equipment on drum brakes are simple: 1. Check that the hose is securely fastened to the HEPA vacuum container and to the brake enclosure. Also http://www.ccar-greenlink.org/Search/1306body.htm 8/9/2006