1. Pressure equipment referred to in Article 4(1) shall be classified by category in accordance with Annex II, according to an ascending level of hazard.
For the purposes of such classification fluids shall be divided into the following two groups:
(a) group 1 consisting of substances and mixtures, as defined in points (7) and (8) of Article 2 of Regulation (EC) No 1272/2008, that are classified as hazardous in accordance with the following physical or health hazard classes laid down in Parts 2 and 3 of Annex I to that Regulation:
(i) unstable explosives or explosives of Divisions 1.1, 1.2, 1.3, 1.4 and 1.5;
(ii) flammable gases, category 1 and 2;
(iii) oxidising gases, category 1;
(iv) flammable liquids, category 1 and 2;
(v) flammable liquids, category 3 where the maximum allowable temperature is above the flashpoint;
(vi) flammable solids, category 1 and 2;
(vii) self-reactive substances and mixtures, type A to F;
(viii) pyrophoric liquids, category 1;
(ix) pyrophoric solids, category 1;
(x) substances and mixtures which in contact with water emit flammable gases, category 1, 2 and 3;
(xi) oxidising liquids, category 1, 2 and 3;
(xii) oxidising solids, category 1, 2 and 3;
(xiii) organic peroxides types A to F;
(xiv) acute oral toxicity, category 1 and 2;
(xv) acute dermal toxicity, category 1 and 2;
(xvi) acute inhalation toxicity, category 1, 2 and 3;
(xvii) specific target organ toxicity – single exposure, category 1.
Group 1 comprises also substances and mixtures contained in pressure equipment with a maximum allowable temperature TS which exceeds the flashpoint of the fluid;
(b) group 2 consisting of substances and mixtures not referred to in point (a).
2. Where a vessel is composed of a number of chambers, it shall be classified in the highest category applicable to the individual chambers. Where a chamber contains several fluids, classification shall be on the basis of the fluid which requires the highest category.