This International Standard specifes test methods for evaluating the effect of hydraulic fuids on standard elastomeric materials that have been manufactured in accordance with specifed processes. It allows baseline comparisons of fuids with standard elastomers.This International Standard provides formulations, mixing procedures and vulcanization procedures for fve types of elastomeric composition:a) acrylonitrile-butadiene rubbers (NBR 1 and NBR 2);b) fuorocarbon rubber (FKM 2);c) ethylene propylene diene rubber (EPDM 1);d) hydrogenated acrylonitrile-butadiene rubber (HNBR 1).These procedures evaluate the effect of mineral-based, fre-resistant and biodegradable hydraulic fuids on such compositions by measurement, under controlled conditions, of physical properties of standard test pieces of the elastomer before and after immersion in the fuids.This International Standard does not provide formulations of elastomeric materials for actual service, although service elastomers may be tested using these compatibility procedures if required.NOTE The elastomeric materials used in these formulations are sensitive to fuid variations and have comparatively high swelling characteristics. Stable cure systems can be used to give adequate storage life.