This International Standard describes the following: a) a multi-pass filtration performance test with continuous contaminant injection for hydraulic fluid power filter elements; b) a procedure for determining the contaminant capacity, particulate removal and differential pressure characteristics; c) a test currently applicable to hydraulic fluid power filter elements that exhibit an average filtration ratio greater than or equal to 75 for particle sizes u 25 µm(c), and a final reservoir gravimetric level of less than 200 mg/L; NOTE It is necessary to determine by validation the range of flow rates and the lower particle size limit that can be used in test facilities. d) a test using ISO medium test dust contaminant and a test fluid in accordance with Annex A. This International Standard is intended to provide a test procedure that yields reproducible test data for appraising the filtration performance of a hydraulic fluid power filter element without influence of electrostatic charge. This International Standard applies to three test conditions: - test condition 1, with a base upstream gravimetric level of 3 mg/L; - test condition 2, with a base upstream gravimetric level of 10 mg/L; - test condition 3, with a base upstream gravimetric level of 15 mg/L.