Table 1. Correlation of grain size phi classes with sieve sizes and numbers for A.S.T.M.
and Tyler mesh sieves.

PHI               NOMINAL SIEVE         SIEVE SIZES                                    SIZE
CLASS        OPENING (MM)             A.S.T.M. #    TYLER #                     FRACTION

4                            0.062                          230                 250
3                            0.125                          120                 115
2                            0.250                            60                   60                             SAND
1                            0.500                            35                   32
0                            1.000                            18                   16

-1                           2.000                            10                     9
-2                           4.000                              5                     5
-3                           8.000                              5/16                2.5                         GRAVEL
-4                         16.000                              5/8                    .624
-5                         32.000                           1 1/4                    -