According to article 13 of the pressure vessel guideline, fluids are categorised in 2 groups Entsprechend Artikel 13 der Druckgeräterichtlinie werden die Fluide in 2 Gruppen eingeteilt:
- Fluid group 1: dangerous fluids (includes all physical dangers and health risks). This fluid also comprises solid substances. A list of theses substances is also found in the CLP regulation (EG) Nr. 1272/2008 annex I
- Fluid group 2: fluids that are not in group 1