In-Depth Survey Report: Evaluation of Brake Drum Service Controls at United States Postal Service, Vehicle Maintenance Facility, Nashville, Tennessee

摘要

The effectiveness of a brake washer assembly unit (Kleer-Flo Model LW-22 Rollabout) for limiting exposure to asbestos (1332214) during the servicing of automotive brakes was evaluated as the U.S. Post Office Maintenance Garage in Nashville, TN. A fleet of 575 Jeep delivery vehicles are serviced at the facility. Most of the vehicles had 13 or 14 inch wheels and 10 inch long brake shoes. Ventilation in the garage was minimal. During winter months, there was no provision for fresh, heated air from the outside. When the 14 bay doors were open in the summer, they provided good ventilation in conjunction with roof fans. One gallon of concentrated detergent, Greasoff No. 19, was used diluted to clean 40 to 50 wheels. Very low asbestos exposures were recorded when the washing assembly was in operation. Personal air samples for the brake mechanics averaged less than the detection limit of 0.004 fibers/cubic centimeter (f/cc) with only one sample above 0.004f/cc. Of the ten vehicles tested, fibers found in the drums were between 83 to 100 percent chrysotile (12001295), with two vehicles having 100 percent asbestos fibers.