The division of Class 2 and the subsidiary hazards depend on the nature of the contents of the aerosol dispenser. The following provisions shall apply:

(a) Division 2.1 applies if the contents include 85% by mass or more flammable components and the chemical heat of combustion is 30 kJ/g or more;

(b) Division 2.2 applies if the contents contain 1% by mass or less flammable components and the heat of combustion is 30 kJ/ or more;

(c) Otherwise the product shall be classified as tested by the test described in the Manual of Test and Criteria, Part III, section 31. Extremly flammable aerosols shall be classified in Division 2.1; non-flammable in Division 2.2;

(d) Gases of Division 2.3 shall not be used as a propellant in an aerosol dispenser;

(e) Where the contents other than the propellant of aerosol dispensers to be ejected aqre classified as Division 6.1 packing groups II or III or Class 8 packing groups II or III, the aerosol shall have a subsidiary hazard of Division 6.1 or Class8;

(f) Aerosols with contents meeting the criteria for packing group I for toxicity or corrosivity shall be prohibited from transport;

(g) Subsiadiary hazard labels may be required for air transport.

Flammable components are flammable liquids, flammable solids or flammable gases and gas mixtures as defined in Notes 1 to 3 of sub-section 31.1.3 of Part III of the Manual of Tests and Criteria. This designation does not cover pyrophoric, self-heating or water-reactive substances. The chemical heat of combustion shall be determined by one of the following methods ASTM D 240, ISO/FDIS 13943: 1999 (E/F) 86.1 to 86.3 or NFPA 30B.