This European Standard refers to particulate air filters for general ventilation. These filters are classified according to their performance as measured in this test procedure. This European Standard contains requirements to be met by particulate air filters. It describes testing methods and the test rig for measuring filter performance. In order to obtain results for comparison and classification purposes, particulate air filters are tested against two synthetic aerosols, a fine aerosol for measurement of filtration efficiency as a function of particle size within a particle size range 0,2 um to 3,0 um, and a coarse one for obtaining information about dust holding capacity and, in the case of coarse filters, filtration efficiency with respect to coarse loading dust (arrestance). This European Standard applies to air filters having an initial efficiency of less than 98 % with respect to 0,4 um particles. Filters should be tested at an air flow rate between 0,24 m3/s (850 m3/h) and 1,5 m3/s (5 400 m3/h). The performance results obtained in accordance with this standard cannot by themselves be quantitatively applied to predict performance in service with regard to efficiency and lifetime. Other factors influencing performance to be taken into account are described in annex A (normative) and annex B (informative).