ASTM C 690

1.1 This test method, one of several found valuable for the measurement of particle size, covers the determination of the particle size distribution of alumina or quartz powders (0.6 to 56.0 µm) using electrical sensing zone particle size analyzers. These instruments use an electric current path of small dimensions which is modulated by individual particle passage through an aperture, and produces individual pulses of amplitude proportional to the particle volume. 1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.3 This standard does not purport to address all of the safety problems, 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.