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 natural diatomaceous   |
   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):          | 50 (or 15 mg/m(3)
 "[*Inert or Nuisance Dusts includes all     |  whichever is the
    mineral, inorganic, and organic dusts    |  the smaller) of
    as indicated by examples in TLV's        |  total dust less
    Appendix D]"                             |  than 1 percent
                                             |  SiO(2)
 Conversion factors.                         |
  mppcf X 35.3 = million particles per cubic |
  meter = particles per c.c.                 |
_____________________________________________|_________________
 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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