1.1 This International Standard specifies the methods to be used for the evaluation of zinc oxide for use in the rubber industry. 1.2 The analytical methods are applicable to all commercial zinc oxides, for example: — direct type (American process); — indirect type (French process); — other types produced by different chemical methods, i.e. precipitation and calcination. Zinc oxide can also be coated with organic materials, such as fatty acids, oil, wetting agents, etc., in order to improve the dispersion in rubber.