1.1 This test method describes a procedure for establishing the sizing accuracy of an automatic, optical liquid-borne single particle counter, using light scattering automatic particle counter (APC). This test method is directed at determining the sizing accuracy of the APC when it is used to measure a challenge suspension of precisely-sized spherical isotropic particles, particularly those sized at and below 1 [mu]m in diameter.

1.2 The particle size parameter that is reported is the equivalent diameter based on the projected area of an isotropic spherical particle of known composition suspended in a liquid that is optically different from the suspended particle. Particles in the size range of 0.1 [mu]m and 5 [mu]m are used for calibration in this procedure.

1.3 This test method does not provide a procedure for APC counting accuracy calibration, since that procedure is available in Practice F658. However, some knowledge of APC maximum concentration capability is necessary in order to avoid introduction of sizing errors as a result of excessive particle concentration during the sizing calibration procedure.

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

1.5 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. For hazard statement, see Section 8.