I'm trying get definitive information about the three dust extractor/vacuum classes (L, M, H). I searched a couple of government agencies related to occupational safety and nothing turned up (or I got thousands of results because it logically or'd my search). I'm looking for the actual document/specification that defines these classes (and the agency that authored it).

To be clear: I'm not looking for "a" definition of these--I'm looking for "the official" definition/spec.

  • Jim, out of curiosity I just tried searching for this from scratch in Google and found the answer in literally five minutes (in a link contained in one of the links).... but the caveat is the search returns are geographically constrained, so what I find searching in Europe and in British English won't be what would be provided to someone searching from the US. Classic problem! (We come across this, in reverse, a lot over here when we're trying to find US or Canadian content.)
    – Graphus
    Commented Aug 27, 2023 at 8:08
  • I think sometimes it all comes down to using the proper search terms. I used "dust extractor classes specification", "dust classes specification", and variants with the word "official", amongst others which I can't remember. I did find some information on a U.K. spec, but there wasn't enough info to tell me it was really what I was looking for. Commented Aug 27, 2023 at 18:34
  • Yes, that's a big part of it even with the level of sophistication of some search algorithms now, which can see beyond the words used (can tell if you've made a typo for example) and sometimes almost seem to read your mind about what you actually want. And then there's this, which is surprisingly difficult to search for! Searching for a specific term, or spec by number, is all well and good once you already know it, but dayum if it doesn't seem like the information wants to hide sometimes ^_^
    – Graphus
    Commented Aug 27, 2023 at 19:42

1 Answer 1


After a bit of research it appears that the definition you are looking for is included in appendix AA of European Standard DIN EN 60335-2-69 link here.

This chart, which I found here points the way.

Unfortunately, the standard itself costs about 400 US dollars, so it's difficult to confirm. The information I've gathered indicates that the classification level (L, M, or H) is based on the allowable exposure level over a defined time period, which in turn is based on the characteristics of the dust (toxicity and particle size). enter image description here

  • Thanks! I agree, looking at the synopsis of that spec it's difficult to determine for sure it'll have the info I'm after (doesn't contain the word "class"). But, the second link you provided (the one with the chart) does seem to tell us it is the right one. I admit I'm disappointed to learn it'll cost me $$ to find out for sure. Thanks again. Commented Aug 27, 2023 at 18:38
  • 1
    @AdirondackJim If there's a university near you, it might be worth checking their library.
    – Mark
    Commented Aug 27, 2023 at 19:55
  • 2
    I searched on that spec and found an appendix at link/(https://www.airum.com/frontend/immagini/files/Annex%20IEC%2060335-2-69.pdf) and a viewer for an older spec [here. These not only confirmed your answer is correct, they answered my questions. I'll mark this as the correct answer. Thanks again. Commented Aug 27, 2023 at 19:57

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