chemicals under pressure
chemicals under pressure (un nos. 3500 to 3505) are assigned to one of the following groups according to their hazardous properties, as follows:
a asphyxiant;
f flammable;
t toxic;
c corrosive;
fc flammable, corrosive; tf toxic, flammable.
the classification depends on the hazard characteristics of the components in the different states:
the propellant; the liquid; or the solid.
note 1: gases, which meet the definition of toxic gases or of oxidizing gases according to 2.2.2.1.5 or gases identified as "considered as pyrophoric" by table note c of table 2 of packing instruction p200 in 4.1.4.1, shall not be used as a propellant in chemicals under pressure.
note 2: chemicals under pressure with contents meeting the criteria for packing group i for toxicity or corrosivity or with contents meeting both the criteria for packing group ii or iii for toxicity and for packing group ii or iii for corrosivity shall not be accepted for carriage under these un numbers.
note 3: chemicals under pressure with components meeting the properties of class 1; liquid desensitized explosives of class 3; self-reactive substances and solid desensitized explosives of class 4.1; class 4.2; class 4.3; class 5.1; class 5.2; class 6.2; or class 7, shall not be used for carriage under these un numbers.
note 4: a chemical under pressure in an aerosol dispenser shall be carried under un no. 1950.
the following criteria shall apply:
(a) assignment to group a shall apply when the contents do not meet the criteria for any other group according to sub-paragraphs (b) to (e) below;
(b) assignment to group f shall apply if one of the components, which can be a pure substance or a mixture, needs to be classified as flammable. flammable components are flammable liquids and liquid mixtures, flammable solids and solid mixtures or flammable gases and gas mixtures meeting the following criteria:
(i) a flammable liquid is a liquid having a flashpoint of not more than 93 °c;
(ii) a flammable solid is a solid which meets the criteria in 2.2.41.1;
(iii) a flammable gas is a gas which meets the criteria in 2.2.2.1.5;
(c) assignment to group t shall apply when the contents, other than the propellant, are classified as dangerous goods of class 6.1, packing groups ii or iii;
(d) assignment to group c shall apply when the contents, other than the propellant, are classified as dangerous goods of class 8, packing groups ii or iii;
(e) when the criteria for two groups amongst groups f, t, and c are met, assignment to groups fc or tf shall apply, as relevant.