AIR FILTER CLASSIFICATION

Classification of general ventilation filters (NF EN ISO 16890)

The classification of filters based on their efficiency is now assessed by the NF EN ISO 16890 standard, which replaced the NF EN 779 standard as of July 1, 2018.

It provides better information for professionals and the general public about the actual protection that can be expected from filters against fine particles in the air, whether taken from the outside or inside if the unit with a filter operates in recirculation mode.

Impact of Fine Particles on the Body

Our body has effective natural defenses against particles larger than 10μm. Below this threshold, air filters constitute the only effective barrier against particles that our body cannot block.

Principles of Classification

Tests are conducted on particles ranging in size from 0.3 to 10 µm to define efficiency -e- across 3 groups: PM1 (particles from 0.3 to 1 µm), PM2.5 (particles from 0.3 to 2.5 µm), and PM10 (particles from 0.3 to 10 µm).

To fall into a certain category, the filter must capture at least 50% of the corresponding particle size. If a filter captures more than 50% of PM1 particles, it is classified as an ISO ePM1 filter. If a filter captures less than 50% of PM10 particles, it is classified as a coarse ISO filter.

• ISO ePM1 > ePM1, minimum ≥ 50%
• ISO ePM2,5 > ePM2,5, minimum ≥ 50%
• ISO ePM10 > ePM10 ≥ 50%
• ISO grossier > ePM10 ≤ 50%, Classification based on initial capture.

Correspondence between NF EN 779 and NF EN ISO 16890

EN 779	ISO 16890
Classes	ePM1	ePM2,5	ePM10	ISO Grossier
G3	–	–	–	≥ 80%
G4	–	–	–	≥ 90%
M5	–	–	≥ 50%
M6	–	≥ 50-65%	≥ 60%
F7	≥ 50-65%	≥ 65-80%	≥ 85%
F8	≥ 65-80%	≥ 80%	≥ 90%
F9	≥ 80%	≥ 95%	≥ 95%	–

Classification of Absolute Filters (NF EN 1822-2019)

Principles of Classification

Very high-efficiency air filters with very low penetration, used in the field of ventilation and air conditioning, as well as in technical processes, such as applications in cleanroom technology or the pharmaceutical industry, are classified in Europe according to this standard.

The standard defines 3 classes:

• Group E: EPA filters (Efficient Particulate Air filters | Efficient Air filters)
• Group H: HEPA filters (High-Efficiency Particulate Air filters | High-Efficiency Air filters)
• Group U: ULPA filters (Ultra-Low Penetration Air filters | Very Low Penetration Air filters)

Absolute filters block at least 85% of the most penetrating particles (MPPS) with sizes ranging from 0.1 to 0.3 μm.

The classification indicates the percentage of MPPS particles retained, ranging from > 85% (class E10) to > 99.999995% (class U17).