CLASS 4 – DIVISION 4.3 :
SUBSTANCES WHICH EMIT FLAMMABLE GASES WHEN IN CONTACT WITH WATER

This division is comprised of substances which when in contact with water may emit flammable gases that can form explosive mixtures with air. Such mixtures are easily ignited by all ordinary sources of ignition, for example naked lights, sparking hand tools or unprotected lamps. The resulting blast wave and flames may endanger people and the environment. In transportation they must be kept in watertight containers, hermetically sealed to avoid the entry of moisture or water vapour.

 

Division 4.3 substances can be in UN Packing Groups I, II, or III.

PACKING GROUPS

  • Packing Group I: must be assigned to any substance which reacts vigorously with water at ambient temperatures and demonstrates generally a tendency for the gas produced to ignite spontaneously, or which reacts readily with water at ambient temperatures such that the rate of evolution of flammable gas is equal to or greater than 10 litres per kilogram of substance over any one minute.

  • Packing Group II: must be assigned to any substance which reacts readily with water at ambient temperatures such that the maximum rate of evolution of flammable gas is equal to or greater than 20 litres per kilogram of substance per hour, and which does not meet the criteria for packing group, or

  • Packing Group III: must be assigned to any substance which reacts slowly with water at ambient temperatures such that the maximum rate of evolution of flammable gas is greater than 1 litre per kilogram of substance per hour, and which does not meet the criteria for packing groups I or II.

 

Commonly Transported Division 4.3 materials

  1. Alkali metals

  2. Aluminium phosphide (in crystal form)

  3. Aluminium powders

  4. Calcium

  5. Cerium

  6. Lithium

  7. Lithium aluminium hydride (ethereal)

  8. Magnesium (powder/alloys)

  9. Potassium metal alloys

  10. Potassium sodium alloys

  11. Sodium

  12. Sodium batteries

  13. Sodium cells

  14. Zinc (powder/dust)