This part of ISO 12500 specifies the test layout and test procedures required for testing hydrocarbon vapour adsorbent filters used in compressed-air systems to determine their effectiveness in removing hydrocarbon vapours. The performance characteristics to be identified are — adsorptive capacity; — pressure drop (Δp). This part of ISO 12500 defines one method of presenting filter performance as hydrocarbon vapour capacity, expressed in milligrams, from results obtained under test conditions.