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Filter classes in the welding fume area - Part II

May 10, 2021 | yourfilter GmbH

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

Part II - The filter classes EPA, HEPA and ULPA: DIN EN 1822:2009

In the last BLOG we dealt with the somewhat "coarser" filter classes and standards. This part is about the standard of HEPA filters.

While the old filter standard of the "coarser" filters was divided into G1-F9, here we find filter classes from E10 - U17. The higher the number, the higher the guaranteed degree of separation. More smaller and larger particles are separated. *

DIN EN 1822:2009

Fig. 1: Standard: DIN EN 1822:2009

Meaning:

EPA = Efficiency Particulate Airfilter

The filter is capable of separating 99.5 % of the 0.1-0.3 µm particles.

HEPA = High Efficiency Particulate Airfilter

The filter is capable of capturing 99.95% of 0.1-0.3 µm particles.

ULPA = Ultra Low Penetration Air

The filter is capable of capturing 99.9995% of 0.1-0.3 µm particles.

In the welding smoke sector, E12 or H13 is common. And most importantly, the filter is only as good as the exhaust arm of the filter system is tracking.

* The evaluation criterion of the separated particles is the so-called MPPS (Most Penetrating Particle Size). The MPPS represents the particle size at which the corresponding air filter records its lowest collection efficiency. For the EPA to ULPA filters, a particle size of 0.1-0.3 µm is indicated here (based on filtration effects).

Here again the particle sizes in relation to each other.

Particle sizes in comparison to human hair

Fig. 2: Particle sizes in comparison

In the next BLOG: Filter classes in welding smoke - Part III: Cleanable filters