Document OJEJ2vEvBJgmJ27pbKqOQpR3e

FILE NAME: Visible Dust (VDT) DATE: 1976 July 8 DOC#: VDT025 DOCUMENT DESCRIPTION: Memo - Asbestos Exposure Associated with Auto Brake Systems INTSSNat CORS5SPONDSMC5 CALS A H D /LASi.'C 5 >Mr. A. R. Clark Mr. J. H. Lloyd Dr. R. J. Sexton Mr. F. Williams i:sn:uis hast f.a eox 2331.chasicsts.i.west Virginia 25 0yt July 8, 1976 O.-igir.-iTirg D?p?. Asbestos Exposure Associated With Automotive Brake Systems At the request of the Plant Medical Department, measurements of personnel exposure to asbestos fibers during brake repair and inspection job tasks have been made. The spirit of cooperation on. the part of Mr. L. M. Hoffman was commendable while wearing personnel samplers during three types of job tasks involving brake maintenance. Discussion of each o the. job performances, together with results is as follows: FIRST: The right rear wheel of a pickup truck was removed for inspection. It was determined that new brake shoes were required and the. mechanic proceeded to vacuum the brake, drum and replace the shoes. He did not wear a respirator as a need was not apparent. Time involved 24 minutes as sampling time. Asbestos fiber count was 0.4 fibers per ml o air with the threshold limit valve. (TLV) being two fibers greater than five micrometers in length. SECOND: The left rear wheel was removed for inspection and the. need for replacement was apparent. At our request, the mechanic wore a 3M respirator and used compressed air to clean the brake drum before changing the brake shoes. Significant quantities of fine dust was generated, which dispersed throughout the shop. Elapsed time and/or sampling time was 19.5 minutes. Asbestos fiber count of fibers greater than five micrometers in length was 0.2 per ml of.air. There was considerable dust collected on the sample but less fibers, possibly due to air dispersion. THIRD: The right front disc brake was removed, inspected, and replaced during a sampling time of two minutes. No air or vacuum was used. The results were 1.9 fibers per ml, which likely indicates the greatest exposure potential associated with routine brake service to be the removal and replacement of the wheel for inspection when additional work is not required. This factor is time related. We are of the opinion that even at the new two-fiber TLV, there is generally no problem with excessive exposure to asbestos in the automotive garage. Use of the recently acquired vacuum capability should continue to be required. The 3M respirators should be used on. any special occasion where dust levels are suspect of being excessive. Mr. Hoffman should be informed of the results of these measurements, and if there are questions, please call me at 6161. rtf -;/ ^Jj/ttVrU-sL A fy/v' -OA' ' H. H* Frazier \J / > r. HUF/kjs IJ C r 008857