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

Table 3

Personal and area task-based samples during brake and clutch work, crane operation, and clothes handling. Brake and clutch repair tasks are listed in the order they were performed.

Activity	Tasks	Sample type	Duration (min)	Volume (L)	PCM—fiber concentration (f/cc)	PCME—chrysotile concentration (f/cc)
Clutch and brake work—day 1
Crane 22B- clutch replacement	Removed clutch band from crane (loosened rusted bolts with pneumatic impact tool)	Personal^A	200	391	0.018	0.013
			198	388	0.028	0.022
Crane 22B- clutch replacement	Removed clutch band linings at workbench (removed rivets with electric grinder, punch, and hammer); cleaned clutch band surface with electric wire brush; blew off debris with compressed air; painted metal band; cut bulk samples from 2 linings	Personal	38	76	0.077	0.036
		Area (1.5 m)	35	180	<0.015	—
Crane 22B- clutch replacement	Installed new linings on clutch band using rivets at workbench	Personal	36	72	<0.0375	—
		Area (1.5 m)	41	211	<0.0128	—
Crane 22B- clutch replacement	Began installing clutch band with new linings on crane	Personal	72	143	<0.0189	—
		Area^B (21.3 m)	113	580	<0.0047	—
Cleanup	Swept up debris from work bench, 22B crane, and floor around the workbench and crane	Personal	30	60	<0.0450	—
		Area^B (21.3 m)	113	580	<0.0047	—
Clutch and brake work—day 2
Crane 22B- clutch and brake work	Finished installing clutch band and then removed brake bands from crane (tightened bolts with pneumatic impact tool)	Personal	151	301	0.032	0.029
		Area (21.3 m)	97^C	492	<0.0055	—
Crane 22B-brake replacement	Removed brake band linings at workbench (removed rivets with electric grinder, punch, and hammer)	Personal	31	62	0.059	0.041
		Area (1.5 m)	32	156	<0.0173	—
Crane 22B- brake replacement	Cleaned brake band surfaces by pneumatic sanding at workbench; blew off debris with compressed air; painted metal bands	Personal	28	56	<0.0482	—
		Area (1.5 m)	27	139	<0.0194	—
Crane 22B- brake replacement	Installed new linings on brake bands using rivets at workbench	Personal	31	62	<0.0435	—
		Area (1.5 m)	26	123	<0.0219	—
Crane 22B- brake replacement	Continued installing new linings on brake bands using rivets at workbench	Personal	25	50	<0.0539	—
		Area (1.5 m)	31	161	<0.0168	—
Crane 22B- brake replacement	Installed brake bands with new linings on crane	Personal	98	195	0.050	0.044
		Area (21.3 m)	42^D	203	<0.0133	—
Additional maintenance tasks at workbench^E	Task #1: blew off a set of used 22B brake linings (1 min 19 sec) and a set of used 15B brake linings (38 sec) that were still on their bands with compressed air	Personal	31	62	0.186	0.186
		Area (1.5 m)	31	150	0.085	0.085
Additional maintenance tasks at workbench^E	Task #2: blew off used 22B clutch linings that were previously sanded with pneumatic sander (1 min 22 sec) and a set of used 15B clutch linings (53 sec) that were still on their bands with compressed air	Personal	29	57	0.155	0.141
		Area (1.5 m)	30	156	0.087	0.082
Cleanup	Swept up debris from work bench, 22B crane, and floor around the workbench and crane	Personal	31	62	0.059	0.000
		Area (1.5, 21.3 m)^F	33	159	0.051	0.051
Clutch and brake work—day 3
Additional maintenance tasks at workbench^E	Task #3: ground off rivet heads on a set of 22B brake bands with electric grinder; hand-sanded the linings while still on their bands (about 4 min); blew off debris with compressed air (about 1 min)	Personal	32	64	0.238	0.238
		Area (1.5 m)	27	136	0.022	0.018
Additional maintenance tasks at workbench^E	Task #4: removed rivets on 22B brake bands with punch and hammer; removed linings; cleaned brake bands using electric wire brush; blew off debris with compressed air; painted metal brake bands	Personal	14	28	0.140	0.140
		Area (1.5 m)	11	58	<0.0465	—
Additional maintenance tasks at workbench^E	Task #5: cleaned a set of used 22B brake linings that were still on their bands with electric wire brush (about 2 min)	Personal	30	60	0.204	0.189
		Area (1.5 m)	30	158	0.037	0.037
Additional maintenance tasks at workbench^E	Task #6: installed woven brake linings on 22B brake band-cut lining to length with hacksaw (about 15 sec); used pneumatic drill to make approximately 30 rivet holes and countersink linings; blew debris from holes with compressed air; attached woven linings to brake band with rivets.	Personal	60	118	0.260	0.260
		Area (1.5 m)	61	320	0.040	0.040
Crane 15B- brake and clutch work	Removed brake and clutch bands from crane	Personal	108^G	216	0.024	0.020
		Area (18.3 m)	129	680	0.007	0.003
Crane 15B- clutch work	Removed linings from clutch band at workbench (removed rivets with punch and hammer); cleaned clutch band surface with pneumatic sander; blew off debris with compressed air; painted metal band.	Personal	45	87	<0.031	—
		Area (1.5 m)	43	223	<0.0121	—
Crane 15B- clutch work	Installed new linings on clutch band at workbench (used pneumatic drill to widen about 50 holes in lining and band to fit existing rivets)	Personal	44	87	0.048	0.039
		Area (1.5 m)	43	222	<0.0122	—
Cleanup	Swept up debris from work bench, 15B crane, and floor around the workbench and crane^H	Area (1.5, 18.3 m)^F	31	159	<0.017	—
Crane operation—day 3
Crane operation	Crane operation including swiveling crane and boom, raising and lowering bucket, and scooping motions with bucket (30 min active operation, with engine idle the remaining time)	Personal (L&R lapels)	36	142	0.021	0.010
			34	135	<0.02	—
		Area (2.4 m)	35	140	<0.0193	—
		Area (2.9 m)	38	152	<0.0177	—
Clothes-handling—day 3
Clothes handling	Handling and shake-out of the three sets of coveralls worn by the mechanic during brake and clutch work on the cranes; approximately the last 2 minutes comprised sweeping up	Personal (L&R lapels)	15	150	0.095	0.000
			15	150	0.079	0.0044
After clothes handling	Samples collected at breathing zone height where the laundry handler was standing; sampling occurred immediately following clothes handling	Area (same location where clothes handler was standing)	15	154	<0.0175	—
			15	154	<0.0175	—

^AThese two samples were also reported on Table 2 since the task duration spanned approximately half the shift. Both samples were collected on the right lapel of the mechanic. No area samples were collected 1.5 m from the workbench during this task. ^BThis area sample spanned the last two consecutive tasks performed on day 1, and thus the results for this sample are listed twice. The area sampler was approximately 21.3 m from the 22B crane and 1.5 m from the workbench. Except for a few minutes spent cleaning the workbench, the mechanic was working at the crane. ^CThis area sample was started 57 minutes after the personal sample. ^DThis area sample was stopped 52 minutes before the personal sample. ^EThe activity “Additional Maintenance Tasks at Bench” refers to work performed at the workbench with brake and clutch linings that were already removed from cranes before the study started. ^FWhen the mechanic was cleaning up at the bench, he was approximately 1.5 m from the area sampler, whereas when he was cleaning up at the 22B or 15B crane he was approximately 21.3 or 18.3 m, respectively, from the area sampler. ^GThis personal sample was started 21 minutes after the area sample. ^HA personal sample was also collected for this task, but the sampling pump shut off prior to the completion of the sampling period, thus the concentration is uncertain.