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.