ASTM C721-14

1.1 This test method covers the determination of the average particle size in micrometres of alumina and silica powders using an air permeability method. The test method is intended to apply to the testing of alumina and silica powders in the particle size range from 0.2 to 50 [mu]m.

1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.

1.3 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.