NIOSH
HAZARD REVIEW
Health
Effects of Occupational Exposure
to
Respirable Crystalline Silica
|
Table
8. Intralaboratory results for evaluation of XRD silica method
|
|||
|
Item
|
Filter
loading
|
||
|
69.4
µg
|
98.4
µg
|
204
µg
|
|
| Degrees of freedom |
12
|
11
|
12
|
| RSD for sampling and analytical methods (%)*,† |
8.8
|
6.3
|
8.1
|
| Source:
NIOSH, BOM [1983]. *RSD = relative standard deviation. RSD for sampling and analytical methods represents the RSD in mass estimates, accounting for intersampler and analytical variability. †Implications for XRD: Pooled filter levels and pump error (assumed to be <5%) indicate that the overall imprecision is as follows: Total RSD for sampling and analytical methods is 9.3%. Therefore, the upper 95% confidence limit on the accuracy (35 degrees of freedom) is 21%. |
|||
|
Table
9. Intralaboratory results for evaluation of IR silica method
|
|||
|
Item
|
Filter
loading
|
||
|
67.2
µg
|
99.7
µg
|
161µg
|
|
| Degrees of freedom |
10
|
12
|
11
|
| RSD for sampling and analytical methods (%)*,† |
5.8
|
7.8
|
7.4
|
| Source:
NIOSH, BOM [1983]. *RSD = relative standard deviation. RSD for sampling and analytical methods represents the RSD in mass estimates, accounting for intersampler and analytical variability. †Implications for IR: Pooled filter levels and pump error (assumed to be <5%) indicate that the overall imprecision is as follows: Total RSD for sampling and analytical methods is 7.1%. Therefore, the upper 95% confidence limit on the accuracy (33 degrees of freedom) is 17%. |
|||
|
Table
10. XRD method evaluation: concentration ranges bracketing applicable
exposure limits for which the NIOSH accuracy criterion is met*
( µg/m3)
|
||||
|
Cyclone
and sampling rate
|
Filter
loading
|
Applicable
exposure limit
|
||
|
69.4
µg
|
98.4
µg
|
204
µg
|
||
| Nylon cyclone, 1.7 L/min |
85
|
121
|
251
|
100
|
| GK2.69 cyclone, 4.2 L/min |
34
|
49
|
102
|
50
|
| *Eight-hour sampled masses are combined with results of NIOSH, BOM [1983]. | ||||
|
Table
11. IR method: concentration ranges bracketing applicable exposure
limits for which the NIOSH accuracy criterion is met*
( µg/m3)
|
||||
|
Cyclone
and sampling rate
|
Filter
loading
|
Applicable
exposure limit
|
||
|
6.72
µg
|
99.7µg
|
161
µg
|
||
| Nylon cyclone, 1.7 L/min |
83
|
123
|
198
|
100
|
| GK2.69 cyclone, 4.2 L/min |
34
|
50
|
80
|
50
|
| *Eight-hour sampled masses are combined with results of NIOSH, BOM [1983]. | ||||
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