This document specifies a method for the determination of the equivalent-sphere particle size distribution of coating powders by laser diffraction, for particles of the size range from 1 µm to 300 µm.

NOTE There is a possibility that particle sizes >300 µm need the use of a different optical model.

This document is specific for the measurement of coating powders and also draws attention to ISO 13320, which provides guidance on instrument qualification and particle size distribution.

Laser diffraction is not suitable for determining oversize material, which can be verified by sieve analysis as described in ISO 8130‑1 or by dynamic image analysis as described in ISO 13322‑2.