scope:

This European Standard specifies a method for the determination of the hydrolytic stability of phosphate ester fire-resistant hydraulic fluids. These fluids fall under category HFDR of EN ISO 6743-4 [2] and categories TSD, TGD and TCD of ISO 6743-5 [3]. Hydrolysis results in the formation of acid, measurement of which is effected by using one of the test methods ISO 6618, ISO 6619 or ISO 7537.Results from two different test methods are not necessarily compatible and direct comparison needs caution. The method is applicable to hydrolytic stability results of up to 0,50 mg KOH/g.