June 2, 2021 | yourfilter GmbH
What different filter classes are there and what is behind the standards?
Part III - The important standard for filter systems with cleanable filter cartridges and filter plates: DIN EN 60335-2-69
The filters we have dealt with so far are disposed of after saturation. But there are also filters that are cleaned in the filter system by compressed air and thus have a longer life cycle. Depending on filter quality and material, the filter withstands hundreds of cleanings. These filters most often bear the designation "Dust Class M" or "BGIA/BIA M". But what does this actually mean?
There is also a valid standard for this: DIN EN 60335-2-69. In this standard, dusts are classified into three different dust classes according to their hazard potential:
- L = low hazard
- M = medium hazard
- H = high hazard
The higher the hazard potential, the higher the requirements for the filter system and filter.

Fig. 1: Welding fumes, the hazard in the workplace
Accordingly, the designation "Dust Class M" indicates that the filters are suitable for systems that can separate dusts with medium hazard. And welding fumes belong to these dusts. Filter cartridges and filter plates should be selected based on whether they correspond to this dust class.
The designations BGIA or BIA of the standard ZH 1/487 are outdated but can still sometimes be found.
Conclusion: For the area of welding fume extraction, be sure to pay attention to the designation Dust Class M!
In the next BLOG article: When are filter changes useful?