This International Standard specifies a method for the determination of the size distribution of particles of vinyl chloride homopolymer and copolymer resins by measuring the amounts retained on a selection of sieves having meshes of various aperture sizes. The results can be expressed either in terms of the amount retained on the individual sieves or as the mean particle size for the whole test sample. The method is not recommended for use with sieves having mesh sizes smaller than 0,038 mm.