|
Construction Standard
Table 1926.55 Appendix A
MINERAL DUSTS
|
 |
| Substance |
|
mppcf [j] |
|
|
| SILICA: |
|
| Crystalline obsolete: see 1910.1000 Z-3 |
|
| QUARTZ |
|
| Threshold limit calculated from the formula |
250[k] |
|
|
|
percent SiO(2)+5 |
| Cristobalite. |
|
| Amorphous, including naturaldiatomaceous earth |
20 |
| SILICATES |
|
| (less than 1 percent crystalline silica) |
|
| Mica |
20 |
| Portland cement |
50 |
| Soapstone |
20 |
| Talc (non-asbestiform) |
20 |
| Talc (fibrous), use asbestos limit |
-- |
| Graphite (natural) |
15 |
|
|
Inert or Nuisance Particulates [m]:
"[*Inert or Nuisance Dusts includes all mineral,
inorganic, and organic dusts as indicated by examples in TLV's
Appendix D]"
|
| 50 (or 15 mg/m(3), whichever is the smaller) of total dust less than 1 percent SiO(2) |
|
| Conversion factors. |
|
mppcf X 35.3 = million particles per cubic meter = particles per c.c.
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Footnote(j) Millions of particles per cubic foot of air, based on
impinger samples counted by light-field techniques.
Footnote(k) The percentage of crystalline silica in the formula is
the amount determined from airborne samples, except in those
instances in which other methods have been shown to be applicable.
Footnote(m) Covers all organic and inorganic particulates not
otherwise regulated. Same as Particulates Not Otherwise Regulated.
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