Dust filter classes: ISO 16890 and EN 779
Air filters for dust are classified under ISO 16890. The standard was published at the end of 2016 and replaced EN 779; by mid-2018 the change was complete.
Classes under ISO 16890
The standard classifies a filter by the size of the particles it captures.
|
Class |
What the class measures |
|---|---|
|
ePM1 |
efficiency on particles of 0.3 to 1 µm |
|
ePM2.5 |
efficiency on particles of 0.3 to 2.5 µm |
|
ePM10 |
efficiency on particles of 0.3 to 10 µm |
|
ISO Coarse |
less than 50% on particles up to 10 µm; classified by the weight of test dust the filter holds back |
Fine dust is particles smaller than 10 micrometres. So the three ePM classes are about fine dust. A filter in the coarse class captures less than half of that fine dust.
The class is followed by a percentage, rounded in steps of 5%. For the ePM classes it is the share of those particles that the filter captures; on a data sheet you will see, for example, ePM1 80%. For ISO Coarse the percentage is about the weight of test dust the filter holds back.
Why EN 779 was replaced
Under EN 779, a filter's efficiency was measured at one particle size: 0.4 µm. The result only said something about that one size. ISO 16890 measures the efficiency across 0.3 to 10 µm, the sizes a filter meets in practice.
If in doubt, ask for the ISO 16890 value from the test report or the data sheet.
The old names G4, M5, F7 and F9
The letters G, M and F come from EN 779. They are still widely used and searched for, for example F7 and G4. Bag filters run from class G3 to F9 in the old system. Data sheets sometimes give both names side by side, such as G4 / ISO Coarse 80% for a pre-filter and F9 / ePM1 80% for a final filter. Those are the values of those filters; another G4 filter can have a different ISO value.
What about HEPA?
HEPA, EPA and ULPA filters have their own standard in Europe: EN 1822.
Next step: See dust filters and HEPA