The international test standard ISO 16890 for air filters for general ventilation

ISO 16890 is an international test standard for air filters that from 1 July 2018 has replaced EN 779. 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.

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.

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 %

Filtration of the different PM fractions of the outdoor air

Particles are also generated inside buildings, so it is not possible to control the quality of the indoor air with calculations of the concentrations of only the outdoor air .

The WHO database contains information on outdoor air pollution and concentrations at various locations around the world. Measurements can be followed in real-time and are measured according to particulate matter (PM). But just knowing the particle content in the outdoor air is not enough to choose the right filter class, you also need to take into account which indoor environment is to be protected. Click here to read about the standard EN 16798-3, we explain how the quality of outdoor and indoor air is categorized and what you should keep in mind when choosing a filter class.

Energy consumption is another important aspect, however, we must never compromise on air quality to save energy "People Matter 1st".

Focus on PM1 to protect our health

PM1 particulate matter is the most important and relevant particle fraction to filter in order to create a healthy indoor air quality (IAQ) that best protects people and processes. This particle size is the most dangerous to us humans because the human body cannot sufficiently protect against it. Such particles penetrate our body through the respiratory system as we inhale them, and they end up deep in our lungs and continue on into our bloodstream. Studies conducted by Lars Ekberg from Chalmers Industriteknik show that an air filter of at least PM1 60% is required to filter hazardous particles from the outdoor air. Learn more in Camfil’s reports PM1 – Fine dust a hazard to health and PM1 – The importance of good indoor air.

Both filter class and airflow affect IAQ

In addition to filters with a high filter class, it is also important to have a sufficient amount of air to achieve good indoor air quality. If you have inadequate air flows, even the cleanest supply of air will not be able to affect the overall indoor air quality.

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Created February 1, 2021