The most widely accepted international standard for filter classification of HEPA and ULPA filters is "EN1822", used by the European Standardization Institute.
Standardized testing shows minimum initial efficiencies for each filter class computer and "leak-free". A special DEHS test aerosol will be used for the test. The particle number on the filter inlet side is measured by a high level particle counter. Fresh air protection, the scanner scans the entire filter surface. The probes ensure that the filter safe air sucks a certain amount of air, and the scattered light particle counters count the particles passing through the filter. In this way, it can show local penetration degree and local filtration. The norm indicates the permissible degree of penetration for each filter class. Finally, the entire penetration value will be calculated. Integral value is the arithmetic mean of local values.
· Standard EN1822:2010 consists of 5 parts:
Part 1: Classification, performance testing, marking,
Part 2: Aerosol production, measuring equipment, particle counting statistics,
Part 3: Testing flat sheet filter media,
Part 4: Determining leakage of filter elements (scan method),
Part 5: Determining the efficiency of filter elements CEN/TC 195 ‘Air Filter for General Ventilation’ elaborated this revision and additions to EN 1822.
Table2: Classification of EPA, HEPA and ULPA Filters
|Filter Group/Filter Class||Integral value|
|E10||≥ 85||≤ 15|
|E10||≥ 95||≤ 5|
|E12||≥ 99,5||≤ 0,5|
|E13||≥ 99,95||≤ 0,05|
|E14||≥ 99,995||≤ 0,005|
|E15||≥ 99,9995||≤ 0,0005|
|E16||≥ 99,99995||≤ 0,00005|
|E17||≥ 99.999995||≤ 0,000005|