Document jZO000qpykV024KKRdBgeNEO

FILE NAME Brakes BRK DATE 1976 DOC BRK170 DOCUMENT DESCRIPTION Two Memos RE Asbestos Exposure with Automotive Brake Systems INTERNAL CORRESPONDENCE A. R. Clark Mr. J. H. Lloyd Dr. R. J. Sexton Mr. F. Williams Date July 8 1976 WEST VIRGINIA 26330 Subject 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 whilewhile wearing personnel samplers during three types of job tasks involving brake maintenanmce aintenance Discussion of each of the job performances together with results is as follows FIRST The right rear wheel of determined that new brake shoes a pickup truck was removed for were required and the mechanic inspection proceeded to It was 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 of 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 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 sampling time of two minutes No air or vacuum was used and replaced during a 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 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 there are questions please call me at the results of 6161 these measurements and if UCC 008857. Frazier 7/ HHFHHF oo Na Na Copy to Mr. J. F. Ballew Building 70-108A INSTITUTE PLANT Jr. Ms. B. J. Mitchell Mr. J. G. Perkins Mr. F. Williams April 6 1976 E.R.- Industrial Hygiene You have asked that measurements be made of personnel exposure to airborne asbestos fibers while weighing dishes are being prepared for residue analyses Our records show that a similar measurement was made in Specifications Laboratory Room 205 March 10 1975 and was reported to be slightly above threshold limit value TLV : Three determinations have recently been made by fiber filter samplers worn by employees while preparing sample dishes Analytical Laboratory Room 108. follows The results of these samplings count on in the are as Date 12/22/75 1/12/76 3/1/76 Employee C. W. Devers D. DeLuca J. O. Good Fiber Count Air 4.9 47.6 7.7 and We observed airborne dust was each of these samplings to be similar in not visible in either instance The TLV technique for asbes- tos dust exposure is currently 5 fibers greater than 5 micrometers per cc of air as a time weighted average TWA exceed 10 fibers greater than 5 micrometers in the TLV will be reduced to 2 fibers as an OSHA and a ceiling value length As of July allowable limit in length not to 1 1976 This job task is only infrequently performed and it is unlikely - that that the the TLV as TWA would ever be exceeded Our measurements however ceiling level can be excessive We therefore recommend that show work involving preparation of sample dishes with asbestos fibers be performed within an exhaust ventilated hood HHF 1s Frazier D. J. D. D. D. D. FrazierFrazier Frazier Frazier Frazier Frazier Frazier H. H. Frazier UCC 008858