ASTM D 1921 : 1996

1.1 These test methods cover the measurement of the particle size of plastic materials in the powdered, granular, or pelleted forms in which they are commonly supplied. As these test methods utilize dry sieving, the lower limit of measurement is considered to be about 38 microns (No. 400 sieve). For smaller particle sizes, sedimentation methods are recommended.

1.2 Two test methods are described:

1.2.1 Test Method A—This test method uses multiple sieves selected to span the particle size of the material. The mean particle diameter and distribution can be determined by this test method.

1.2.2 Test Method B—This test method is an abbreviated version of Test Method A conducted with a few specific sieves. This test method determines "percent passing" or "percent retained" on a given sieve. Test Method B is applicable to materials which do not have a normal particle size distribution such as pellets and cubes.

1.3 The values as stated in inch-pound units are to be regarded as the standard. The values given in parentheses are given for information only.

1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

Note 1-—There is no technically equivalent ISO standard.