Document 6BjmvkDnMwad9GBJLXbvwj7D3

It f' : l .> ' . A I t* I r I I f V VV t .1 :t I. I i R* IK l>. I!. IIickkii and K. I.. Knkiiit T*llir 2. IV'RMINAI. KAMI'I IS IIURINO CAR I'KAKf SfKVICt. Sample Concentration (librcs/cm*) 1 2 3 4 S 6 Time-weighted average 063 1-12 021 096 038 079 0-68 EXPOSURE DURING TRUCK SERV1CINO Maintenance of truck brakes involves a somewhat different type of operator exposure us the servicing is more complex, and therefore the number of vehicles dealt with is less. The larger sire of wheels and drums, on the other hand, makes it difficult for the operator to avoid the dust cloud produced, and personal exposure could be higher than that during car maintenance. Further sampling was therefore carried out in a large fleet workshop with equipment similar to that used for the passenger car tests. Static samples, each of approximately 3 hr duration, were collected during the morning and afternoon periods at three positions; at the bay adjacent to the one at which brake cleaning was carried out, at the next bay, and in the centre of the garage. Brakes were blown but during the morning, but not during the afternoon. The results are given in Table 3. Table 3. General atmosehere rambles durino truck brake service Location of sample Concentration (fibres/cm1) Adjacent bay 2 Bays away Centre of garage Morning Afternoon Morning Afternoon Morning Afternoon 0-28 007 017 0-07 049 Oil Personal samples were obtained from two men--the man engaged on brake cleaning, and the man engaged on clutch repair work at the adjacent bay. The first period of 1 *5-2 hr included the period of brake denning, and the second period of approximately 5 hr represented the remainder of the shift. The results are shown in Table 4. i