Evaluation of Airborne Asbestos Concentrations Associated with the Operation and Maintenance of Brakes and Clutches on Nonautomated Heavy Equipment
Table 2
Full-shift and half-shift samples during clutch and brake work.
Sample
Duration (hr)
Volume (L)
PCM—fiber concentration (f/cc)
PCME—chrysotile concentration (f/cc)
Indoor
Personal—day 1
Full-shift
6.15
380
0.0136
0.0053
1st half-shift
3.33
391
0.0182
0.0132
1st half-shift
3.30
388
0.0278
0.0225
2nd half-shift
2.75
330
0.0163
0.0077
Average full-shiftA,B
0.0168
0.0093
Personal—day 2
Full-shift
8.45
510
<0.0053
—
1st half-shift
3.62
215
<0.0125
—
2nd half-shift
4.78
285
0.1454
0.1454
Average full-shiftA,C
0.0414
0.0414
Personal—day 3
Full-shift
6.42
360
0.0368
0.0359
1st half-shift
2.70
161
0.096
0.0960
2nd half-shift
3.67
205
0.0215
0.0215
Average full-shiftA
0.0449
0.0445
Average full-shift—days 1, 2, and 3
0.0344
0.0317
Area: 1.5 m from crane
Day 1—crane 22B
6.40
1922
0.0029
0.0012
Day 2—crane 22B
9.02
2696
0.0028
0.0025
Day 3—crane 15B
6.73
2019
0.0030
0.0030
Average full-shift
0.0029
0.0023
Area: 4.6 m from crane
Day 1—crane 22B
6.28
1907
0.0017
0.0009
Day 2—crane 22B
8.92
2899
0.0035
0.0035
Day 3—crane 15B
7.93
2381
0.0027
0.0027
Average full-shift
0.0026
0.0024
Area: 9.1 m from crane
Day 1—crane 22B
5.62
1686
0.0019
0.0011
Day 2—crane 22B
8.93
2659
0.0048
0.0047
Day 3—crane 15B
8.28
2474
0.0018
0.0017
Average full-shift
0.0028
0.0025
Area: 4.6 m from workbench
Day 1
6.07
1850
0.0025
0.0008
Day 2
8.93
2744
0.0029
0.0028
Day 3
8.80
2688
0.0036
0.0036
Average full-shift
0.0030
0.0024
Area: 9.6 m from workbench
Day 1
5.78
1750
0.0029
0.0016
Day 2
8.98
2744
0.0038
0.0038
Day 3
8.87
2691
0.0032
0.0032
Average full-shift
0.0033
0.0029
Outdoor
Day 1—full shift
7.33
2380
<0.0011
—
Day 1—full shift
7.33
2197
<0.0012
—
Day 2—partial shiftD
5.47
1761
<0.0015
—
Day 2—partial shiftD
3.82
1142
0.0034
0.0034
Day 3—full shift
7.42
2202
<0.0012
—
Day 3—full shift
7.32
2144
<0.0013
—
Average full-shiftC
0.00047
0.00047
AThe half-shift samples were averaged (weighted by time) to calculate a second full-shift concentration for each day. The measured and calculated full-shift concentrations were averaged to yield the daily average full-shift concentration. BOn day 1, there were two samplers consecutively operating for the duration of the first half of the shift. These two samples were averaged together before the calculations described in footnote (a) were carried out. CTo calculate an average concentration, PCM measurements below the analytical sensitivity were assigned a value of zero. Likewise, the corresponding chrysotile-specific concentrations (PCME) were assumed to be zero. D On day 2, outdoor sampling was conducted at a single location. The sampling stand blew over part way through the day, at which time the sampler was replaced. The full-shift TWA concentration for day 2 is 0.0014 f/cc (PCME).
