ISO 16890 classifies air filters based on particulate matter (PM), which makes it possible to directly see connections to our health and air pollutants. The standard also makes it possible to plan indoor air quality (IAQ) in a completely different way than before.
Efficiency classification of air filter
For a filter to be classified in any of the three PM classes, a degree of separation of at least 50% of the particle fraction is required. If a filter does not pass 50% separation in any of the PM fractions, the filter gets a filter class in the group Coarse (coarse filter). The degree of filtration is an average with and without static charge. The filter is also assigned a percentage linked to the PM group within which the filter can classify itself. The percentage is rounded down to an even 5%. Below are the different filter classes that a filter can be assigned (30 different classes and Coarse).
Filtering efficiency for different filter classes
Example 1
- 63 % of the PM1 fraction
- 70 % of the fraction PM 2,5
- 91 % of the PM 10 fraction
The filter can handle more than 50% separation in fraction PM1 and is therefore assigned ePM1, the percentage is rounded down to an even 5%. Filter class becomes: ePM1 60 %
Example 2
- 15 % of fraction PM1
- 26 % of the fraction PM 2.5
- 64 % of the fraction PM 10
The filter can handle less than 50% separation in the PM1 and PM 2.5 fractions. It is instead awarded ePM10, the percentage is rounded down to an even 5%. Filter class will therefore be: ePM10 60 %
What is new?
Previous standard EN 779 rated air filters from G1-F9 and the efficiency rating for M5-F9 was based on an average particle size of 0.4 µm (micrometers). ISO 16890 instead calculates the degree of filtration based on the particle mass in three different size fractions PM1 (0.3-1.0 µm), PM2.5 (0.3-2.5 µm) and PM10 (0.3-10 µm). The filter is then assigned a filter class in one of these three groups or is classified as a Coarse (coarse filter).
This difference means filters that previously had the same class according to EN 779 can be assigned different classes according to ISO 16890. There is therefore no direct comparison or conversion of the filter classes of the different standards.