Maritime Standard
Table 1915.1000 Z-SHIPYARD

 

 

                      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)
                                             |   whichever is the
                                             |   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.             |
_____________________________________________|_____________________
 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.
tracking image