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Filter classes in the welding fume sector - Part I

April 28, 2021 | yourfilter GmbH

What different filter classes are there and what is behind the standards?

Part I - Two standards in comparison
DIN EN 779: 2012 vs. DIN EN ISO 16890: 2017

The filter classes of the standard DIN EN 779:2012 are very well known and still often used:
  • G1-G4 (Grobstaubfilter)
  • M5-M6 (middle dust filter)
  • F7-F9 (Feinstaubfilter)
Norm: DIN EN 779:2012

Abb. 1: Norm: DIN EN 779: 2012

This classification was replaced by the DIN ISO 16890 standard at the beginning of 2017. When dividing the filter classes according to the "old" standard, it was only tested how many particles with a size of 0.4 µm were filtered. However, this does not correspond to real conditions. Because: Dusts have different particle sizes.

This is exactly what the new classification according to DIN EN ISO 16890:2017 reflects. There is a subdivision according to the particle sizes 1 µm, 2.5 µm and 10 µm.  

For comparison: A hair has a diameter of about 50-70 µm, a fine grain of sand is about 90 µm in size.Partikelgrössen im Vergleich

Fig. 2: Comparison of particle sizes 1 - 60 µm

The filter classes according to the new standard

A complete comparison of the filter classes between the old and new standard is therefore not possible. The filters must have been retested according to the new standard and then receive a new filter class that states how high the separation efficiency of the respective particle size is:

  • ePM1 ≥ 50%
  • ePM2.5 ≥ 50 %
  • ePM10 50%
  • or "Coarse"
"Coarse" is the name of a coarse dust filter that lets many small particles through. The "e" just stands for "efficiency".

Norm: DIN ISO 16890

Abb. 3: Standard: DIN ISO 16890: 2017

Note: The smaller the specified particle and the higher the degree of separation (50%, 60%, 70%), the better the air filtration works.

It continues in the next BLOG "Filter classes in the welding fume area - Part II" with DIN EN 1822:2009 for the particulate filters (EPA and HEPA filters).