Classification of dust, e.g. fineness, health risk (cf. IEC 60335-2-69)
- Dust class L < 1 % max. penetration
- Dust class M < 0,1 % max. penetration
- Dust class H < 0,005 % max. penetration
For asbestos-containing dusts and flammable dusts of all explosion classes, there are additional requirements.