This standard addresses two air-cleaner performance characteristics of importance to users: the ability of the device to remove particles from the airstream and its resistance to airflow.
A method of loading the air cleaner with synthetic dust to simulate field conditions is described. The performance efficiency is calculated and is the basis to determine the minimum efficiency reporting value (MERV).
The ISO 16890 standard for filter testing and assessment replaced the previous EN 779 standard in mid-2018. Now, filter efficiencies will be determined with regard to the particulate classes PM1, PM2,5 and PM10, as well as coarse dust. The ISO 16890 standard is thus based on the same evaluation parameters used by the WHO and other environmental authorities.
In Europe, EPA, HEPA and ULPA filters are subject to classification according to EN 1822 for filtration efficiency and zero leakage. HEPA and ULPA filters are also subject to individual tests. The international standard ISO 29463 is based on European standard EN 1822 and will probably replace this standard in the future. Both standards are based on the latest particle counting methods.
With the revised test standard ISO 29461 Part 1 a new classification system for air filters in the intake filtration of turbomachinery comes into force. The target-group oriented T-classification system links the two existing test standards ISO 16890 and ISO 29463/EN 1822 via a consistent system of filter classes for static intake air filters.
The EN 779 standard "Particulate air filters for general ventilation" defined the test procedure for coarse and fine dust filters. The EN 779:2012 version valid from April 2012 until mid-2018 included the introduction of minimum efficiency levels for classes F7 to F9, and the renaming of classes F5 and F6 to M5 and M6. Since mid-2018, EN 779 has been completely replaced by the ISO 16890 standard in Europe.
Filter media used in dust removal machines is tested according to the SBM dust class DIN EN 60335-2-69 appendix AA. The maximum degree of penetration decides whether a filter material is classified as an L, M or H class.