CLASS 4 – DIVISION 4.2 - SUBSTANCES LIABLE TO SPONTANEOUS COMBUSTION

This division is comprised of substances that are liable to spontaneous heating under normal transport conditions or heating up in contact with air and are consequently liable to catch fire due to such heating. They include pyrophoric substances and self-heating substances.

 

Division 4.2 substances can be in UN Packing Groups I, II, or III.

  • Pyrophoric substances are substances, including mixtures and solutions (liquid or solid), which even in small quantities ignite within five minutes of coming in contact with air. These Division 4.2 substances are the most liable to spontaneous combustion.

  • Self-heating substances are substances, other than pyrophoric substances, which in contact with air without energy supply are liable to self heating. These substances will ignite only when in large amounts (kilograms) and after long periods of time (hours or days).

PACKING GROUPS

  • Packing group I: Pyrophoric liquids and solids.

  • Packing group II: if a self-heating material gives a positive test result when tested with a 25 mm cube size sample at 140°C;

  • Packing group III: Packing group III must be assigned to self-heating substances if:
    (a) a positive result is obtained in a test using a 100 mm sample cube at 140 °C and a negative result is obtained in a test using a 25 mm cube sample at 140 °C and the substance is to be transported in packages with a volume of more than 3 m3;
    (b) a positive result is obtained in a test using a 100 mm sample cube at 140 °C and a negative result is obtained in a test using a 25 mm cube sample at 140 °C, a positive result is obtained in a test using a 100 mm cube sample at 120 °C and the substance is to be transported in packages with a volume of more than 450 litres;
    (c) a positive result is obtained in a test using a 100 mm sample cube at 140 °C and a negative result is obtained in a test using a 25 mm cube sample at 140 °C and a positive result is obtained in a test using a 100 mm cube sample at 100 °C.if a positive test result is obtained on a self-heating material in a test using a 100 mm sample cube at 140°C, 120°C or 100°C depending on packaging volume;

 

Commonly transported Division 4.2 substances:

  1. Carbon, activated 

  2. Copra (dried coconut kernels)

  3. Fish meal (unstabilized)

  4. Iron oxide (spent)

  5. Iron sponge/direct-reduced iron (spent)

  6. Oily cotton waste

  7. Oily fabrics or fibres (animal, vegetable, or synthetic)

  8. Sodium hydrosulphite

  9. Sodium sulphide, anhydrous

  10. Seed cake

  11. White phospherous