Air filtration

A high concentration of fine dust such as pollens, bacteria, exhaust gases in the air is harmful to health. The PM2.5 and PM1 particles in particular reach our airways and mingle with the bloodstream, possibly even reaching the brain.
The use of filters in your heat recovery system reduces the level of harmful particles in a living room, we take stock of the new filtration standard.
(Zehnder Group)

ISO 16890 at a glance

The ISO 16890 standard is said to be a realistic assessment of filter performance and measures the ability of the filter to stop different sizes of particulates from penetrating a ventilation system and entering an indoor climate. EN779, the previous standard, only measured a single particle size of 0.4μm to assess filter performance; yet fine dust such as soot or pollen comes in varying sizes.

In addition, ISO now divides filters into four classes which have the ability to filter a certain particle span out of the air. In order to be assigned a category, except for ISO Coarse, a filter must separate at least 50% of the respective particle size. ISO Coarse filters can separate less than 50% of the particulates.

Filters are classified as:

ISO Coarse: Ability to filter particulates greater than 10μm in size. This includes larger particles such as sand, fluff, flying seeds or fine hair.

ISO ePM10: Ability to prevent particles between 10μm to 2.5μm in size. Smaller than ISO Coarse particulates, they typically come in the form of pollen, stone dust or agricultural dust.

ISO ePM2.5: Prevent even smaller sized particulates, less than 2.5μm in size; fungi, mold spores, pollen or toner powder are all able to be filtered out.

ISO ePM1: The most effective filter, having the ability to prevent air-borne sea salt, oil mist or other particles smaller than 1μm from penetrating through the filter. An example of the ISO ePM1 (previously F7) filter would be used with Zehnder’s ComfoAir Q MVHR system.

Why specifying the correct filter is important

An average person inhales up to 15kg of air per day. Should there be a high concentration of fine particles in the air, such as spores or soot, the body can be directly affected. Once inhaled, they can affect our sleep, concentration and overall health. When Zehnder developed their filtration systems, performance was of great importance for this very reason.  

When selecting an MVHR system filter for a development or refurbishment project, it is vital the appropriate classification of filter is supported, to meet necessary requirements depending on what the building may be exposed to.

Do I need a new filter with the introduction of ISO 16890?

Even prior to the introduction of the new measurement standards, all of Zehnder’s filtration solutions were fully compliant with all the new requirements – only the measurability is new.

If you are using Zehnder’s filters that have the old EN 779 standards (G4/F7 for example), do not worry – they can still be used.

We invite you to visit the blog of ZEHNDER UK for more information !