What is a Filter Class?

Filter class is a term used to describe the efficiency of a filter. In the coming years, filter class designations such as G1 to G4, M5, M6, F7 to F9 will slowly be replaced by a new standard in accordance to the new ISO 16890 filter norm. To clarify we have made an overview of the 'old' filter classes and with which filter class they will be replaced.

ISO 16890 Test method

The EN ISO 16890 test method focuses on the size of the particles that can be captured by the filter material.

The old test method only took into account the filtering power, without paying attention to the type of particles that were filtered.

In this new method, a clearer comparison with particle emissions in other contexts becomes possible.

The table below shows how the 'old' classifications (according to the EN 779: 2012 standard) can be compared to the new classifications (EN ISO 16890). One can not just translate the old classification into the new classification, but in the image we show how the two classifications can be seen in relation to each other.

ISO 16890 uses new descriptions, classifying the efficiency of the filtering in relation to the size of the particles.

PM1, PM2.5, and PM10 indicate the size of the particles in μm, where 10 (μm) is the largest particle and 1 (μm) is the smallest particle. An e is placed before PM (ePM). This indicates the filtration power efficiency for the particle size, which is indicated in %. For example, a filter that complies with ISO ePM1 (> 55%) can collect more than 55% of the particles with a size of 1 μm.


The 'old' filter classification and the EN779 standard

The HRV Filter class is a term used with air filters to indicate the efficiency of a filter. A filter class is assigned on the basis of tests included in the EN779 standard and based on the percentage of pollution captured. Filters are categorized as follows: G1 to G4 and M5 to M6 and F7 to F9. In category G, G4 has the highest ranking and is of the best quality likewise an F9 filter in the F category. These filters capture the most dirt and dust in their respective category. For filters within the G-class, fairair uses G4 as a standard.

filter class and EN779 standard

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