8 number of sieve classes 12.7 19.05 0.00000667 mimimum diameter, maximum diameter, number fraction 9.525 12.7 0.0000996 for each sieve class 4.75 9.525 0.000255 (diameters are in real physical units, e.g., mm) 2.36 4.75 0.000475 1.18 2.36 0.007725 0.6 1.18 0.051209 0.3 0.6 0.313411 0.15 0.3 0.626821