Filter marking according to iso 16890

In July 2018, the new standard for air filters ISO 16890 came into force, the main task of which is to unify various standards for labeling air filters used around the world.

Contaminants in the air can occur in solid and liquid states. In general, solid contaminants in the air can be described as dust, as long as the way in which they were created does not play an important role.
The main reason for the introduction of this new standard were studies that looked at the effects of particulate matter on human health. The original EN 779 standard only divided filters for medium-coarse and fine dust into individual classes (M5-F9) based on their average efficiency at a particle size of 0.4 µm.

The new standard ISO 16890 divides dust particles in the air into four PM fine dust spectra (PM abbreviation Particulate Matter = fine dust) according to their size:b):

When filters are tested in accordance with this new ISO 16890 standard, the laboratory results better reflect the filter's separation performance under real conditions and in actual operation.

Since filter media can be manufactured from different materials and using different manufacturing processes, the basic parameters first had to be defined, based on which all filter types can be classified into the corresponding filter classes.

The basic parameters for classifying the filters into the filter classes are:
a) The parameter ePMx
This parameter describes the medium separation efficiency of the filtration for the respective PM class (how much fine dust and what particle size can the filter separate on average).

b) The parameter ePMx,min
This parameter describes the Minimum separation efficiency of the filtration for fine dust in an electrostatically discharged state. Electrostatic dust separation is one of the possible filtration mechanisms, which is mainly used with synthetic filtration media. These synthetic media can be electrostatically charged, increasing their efficiency.
Based on these two measured parameters, filters can be divided into four different filter classes:

For the classification of a filter into a specific filter class it is therefore necessary Minimum separation efficiency of the filtration crucial in the electrostatically discharged state. As soon as the filter class is defined for the given filter, information about it follows medium separation efficiency the filtration, e.g. B. ISO ePM1 80%.

Examples of filter labeling:

ISO ePM1 80%

- the efficiency of the filter refers to the particle spectrum PM1 (0.3µm 1µm))
- the minimum separation efficiency of the filtration in the electrostatically discharged state is greater than 50% for PM1
- the average separation efficiency of the filtration is between 80% - 85% (rounded to full 5% increments)

ISO ePM2.5 65%

- the efficiency of the filter refers to the particle spectrum PM2.5 (0.3µm 2.5µm))
- the minimum separation efficiency of the filtration in the electrostatically discharged state is greater than 50% for PM2.5
- the average separation efficiency of the filtration is between 65% - 70% (rounded to full 5% increments)

ISO ePM10 70%

- the efficiency of the filter refers to the particle spectrum PM10 (0.3µm 10µm))
- the minimum separation efficiency of the filtration in the electrostatically discharged state is greater than 50% for PM10
- the average separation efficiency of the filtration is between 70% - 75% (rounded to full 5% increments)

A filter with the ISO ePM2.5 65% label achieves good parameters in the PM2.5 filter class, where it can separate 65% - 70% of the dust in the respective particle spectrum. However, it is no longer clear from the name of this filter how its efficiency behaves in the PM1 particle spectrum.
These filters also achieve average efficiencies of greater than 50% in class PM1, but they are not able to achieve these efficiencies in an electrostatically discharged state. Here the efficiency ranges between 40% - 50%. That is why the filters must be labeled with class PM2.5, in which they are already able to achieve the required minimum efficiency in an electrostatically discharged state.

In contrast, a filter with the ISO ePM1 80% marking for filter class PM1 achieves an efficiency of greater than 50% even in an electrostatically discharged state and can therefore separate more fine dust. This filter will be significantly more effective and should therefore be used preferably.

Literature and sources used
RUKATECH, sro : Internal documents
Robatherm GmbH: Publicly accessible documents
Zehnder Group Deutschland GmbH: Publicly accessible documents

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