scope:

This International Standard refers to particulate air filters for general ventilation having an initial efficiency of less than 99 % with respect to 0,4 µm particles. Filters used in the ventilation of low-rise residential buildings or portable room-air cleaners are excluded from the scope of this standard. It describes the technical specifications, requirements and a method of test for the fractional efficiency measurement and resistance to airflow. The method is applicable for air flow rates between 0,25 m³/s (900 m³/h, 530 ft³/min) and 1,5 m³/s (5400 m³/h, 3178 ft³/min), referring to a test duct with a nominal face area of 0,61 m x 0,61 m. Filters in the higher end and above 99 % initial efficiency with respect to 0,4 µm particles are tested and classified according to other standards (see ISO 29463, part 1-5). Filters according to this series of standards are rated by their removal efficiency to PM10, PM2.5 and PM1 aerosol fractions. The particle collection efficiency of the filter element is measured as a function of the particle size in the range of 0,3 to 10 µm of the unloaded and unconditioned filter element. In a second step, a full filter element shall be conditioned (discharged) in an artificial aging step to provide information about the intensity of the electrostatic removal mechanism. The results from this second step are used to calculate the average efficiency in each of the PM10, PM2.5 and PM1 size ranges by weighting the fractional efficiency values according to the standardized and normalized particle size distribution of the related fraction of the ambient aerosol. This standardized and normalized particle size distribution is defined in this standard