4.1 Three forces can mechanically degrade a granular activated carbon: impact, crushing, and attrition. Of these three, attrition, or abrasion, is the most common cause of dust formation in actual service. Published test procedures to determine the "hardness" of activated carbons produce results that in general cannot be correlated with field experience. For example, the ball-pan hardness test applies all three forces to the sample in a variable manner determined by the size, shape, and density of the particles. The "stirring bar" abrasion test measures attrition so long as the particle size is smaller than 12 mesh. There is some evidence, however, that the results of this test method are influenced by particle geometry. The procedure set forth in this guide measures the effect of friction forces between vibrating or slowly moving particles during the test and may be only slightly dependent on particle size, shape and density effects.

1.1 This guide presents a procedure for evaluating the resistance to dusting attrition of granular activated carbons. For the purpose of this guide, the dust attrition coefficient, DA, is defined as the weight (or calculated volume) of dust per unit time, collected on a preweighed filter, in a given vibrating device during a designated time per unit weight of carbon. The initial dust content of the sample may also be determined. Granular activated carbon is defined as a minimum of 90 % being larger than 80 mesh (0.18 mm) (see Test Methods D2867).

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

1.3 This guide 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 guide to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.