ISO 4793:1980

Laboratory sintered (fritted) filters — Porosity grading, classification and designation

Filters are graded according to their pore size index in one of the eight classes specified. This is applicable to laboratory filters made of glass, vitreous silica, ceramics, metals and plastic materials. Annex A specifies a method for determination of pore size index. Annex B and C concern with a procedure for assessing uniformity of filters and for determination of air permeability.