1.1 ,This test method covers the determination of the relative attrition characteristics of FCC catalysts by means of air jet attrition. Other fine powder catalysts can be analyzed by this test method but the precision of this test method has been determined only for FCC catalysts. It is applicable to spherically or irregularly shaped particles which range in size between 10 and 180 μ,m, have skeletal densities between 2.4 and 3.0 g/cm³ (2400 and 3000 ,kg/m³) (see IEEE/ASTM SI-10) and are insoluble in water. Particles less than 20 μ,m are considered fines.