Evaluation of Airborne Asbestos Concentrations Associated with the Operation and Maintenance of Brakes and Clutches on Nonautomated Heavy Equipment

Table 1

Overview of air samples collected during crane maintenance^A.

Day	Crane maintenance	Additional maintenance tasks^B	Personal samples	Full-shift area samples (one sample/day)	Number of task-based area samples (1.5 m from workbench, 18–21 m from cranes)^C
1	Clutch band removed from 22B crane, relined, and almost completely reinstalled; shop cleanup	None	1 full-shift; 2 partial-shift; 5 task-based	1.5 m from 22B crane; 4.6 m from 22B crane; 9.1 m from 22B crane; 4.6 m from workbench; 9.6 m from workbench;	4 samples
2	Finished reinstalling 22B clutch band; brake bands removed from 22B crane, relined, and reinstalled; shop cleanup	(1) Compressed air blowoff of brake linings; (2) Compressed air blowoff of clutch linings	1 full-shift; 2 partial-shift; 9 task-based	1.5 m from 22B crane; 4.6 m from 22B crane; 9.1 m from 22B crane; 4.6 m from workbench; 9.6 m from workbench;	9 samples
3	Clutch and brake bands removed from 15B crane, and clutch bands relined; shop cleanup	(3) Sanded brake linings and blew off with compressed air; (4) Removed brake linings, cleaned and painted brake bands; (5) Cleaned brake lining surface with electric wire brush; (6) Measured, cut, and installed woven brake linings	1 full-shift; 2 partial-shift; 8 task-based	1.5 m from 15B crane; 4.6 m from 15B crane; 9.1 m from 15B crane; 4.6 m from workbench; 9.6 m from workbench;	8 samples

^ASamples were collected in accordance with the NIOSH methods 7400 and 7402. Flow rates were approximately 1-2 L/min for personal samples and 5 L/min for area samples. ^BTasks performed on brake and clutch bands that were removed from the crane prior to the start of the study. ^CTask-based area samples were collected 1.5 m from workbench, including during tasks performed on the cranes which were 18.3 to 21.3 m from the stationary sampler.