This International Standard specifies two methods for determining, by measurement of the transmission rate, the permeability of rubber to volatile liquids diffusing into open air. It is applicable only to materials in sheet form and to coated fabrics having thicknesses between 0,2 mm and 3,0 mm. It is restricted to transmission rates of more than 0,1 g/m2·h. The methods are particularly useful for comparing the relative transmission rates of one liquid through different materials, or of several liquids through one material. Method A, with refilling, is used when testing mixtures of liquids which give different transmission rates. Method B, with no refilling, is used for a single-component liquid. NOTE A method for the determination of water vapour transmission rate is given in ISO 2528, Sheet materials — Determination of water vapour transmission rate — Gravimetric (dish) method.