It is necessary to know the distribution of particle sizes of granular activated carbon in order to provide proper contact of gases or liquid in a packed bed of the material. Changes in particle size distribution can affect the pressure drop across the bed and the rate of adsorption in a bed of a given size.

Mean particle diameter is a property of activated carbons that influences pressure drop.

Effective size and uniformity coefficient are two properties of activated carbons often of interest in municipal water treatment applications where control of particle size is of interest.

1.1 This test method covers the determination of the particle size distribution of granular activated carbon. For the purposes of this test, granular activated carbon is defined as a minimum of 90 % of the sample weight being retained on a 180-μm Standard sieve. A U.S. mesh 80 sieve is equivalent to a 180-μm Standard sieve.

Note 1—For extruded carbons, as the length/diameter ratio of the particles increases, the validity of the test results might be affected.

1.2 The data obtained may also be used to calculate mean particle diameter (MPD), effective size, and uniformity coefficient.

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.