The Pressure Equipment (Safety) Regulations 2016

3.  For the purposes of the classification referred to in paragraph (1), fluids shall be divided into the following two groups—

(1) a fluid in Group 1 means—

(a) a substance or mixture—

(i) as defined in Article 2(7) and (8) respectively of the CLP Regulation; and

(ii) that is classified as hazardous in accordance with the following physical or health hazard classes laid down in Parts 2 and 3 of Annex I to the CLP Regulation—

(aa) unstable explosives or explosives of Divisions 1.1, 1.2, 1.3, 1.4 and 1.5;

(bb) flammable gases, categories 1 and 2;

(cc) oxidising gases, category 1;

(dd) flammable liquids, categories 1 and 2;

(ee) flammable liquids, category 3 where the maximum allowable temperature is above the flashpoint;

(ff) flammable solids, categories 1 and 2;

(gg) self-reactive substances and mixtures, types A to F;

(hh) pyrophoric liquids category 1;

(ii) pyrophoric solids, category 1;

(jj) substances and mixtures which in contact with water emit flammable gases, categories 1, 2 and 3;

(kk) oxidising liquids, categories 1, 2 and 3;

(ll) oxidising solids, categories 1, 2 and 3;

(mm) organic peroxides, types A to F;

(nn) acute oral toxicity, categories 1 and 2;

(oo) acute dermal toxicity, categories 1 and 2;

(pp) acute inhalation toxicity, categories 1, 2 and 3;

(qq) specific target organ toxicity – single exposure, category 1; or

(b) a substance or mixture contained in pressure equipment with a maximum allowable temperature TS which exceeds the flashpoint of the fluid;

(2) a fluid in Group 2 means any substance or mixture which is not a substance or mixture within the definition of a fluid in group 1.