IATA Class 4 Division 4.3 Substances Dangerous When Wet

Division 4.3 is for substances that are dangerous when wet. When these substances interact with water, they are liable to become spontaneously flammable or to give off flammable gas in dangerous quantities. Mixtures of these substances are easily ignited by all ordinary sources of ignition, such as sparks. During testing described in the UN Manual of Tests and Criteria, Part III, Subsection 33.4.1., substances are assigned to Division 4.3 if spontaneous ignition takes place during any step of the procedure or if there is an evolution of a flammable gas at a rate greater than 1 L/kg of the substance per hour. The test method can apply to solids and liquids, but it does not apply to pyrophoric substances. The substance must be tested at an ambient temperature when it comes in contact with water.

Division 4.3 substances are assigned to Packing Group I if they react vigorously with water at ambient temperatures and if they demonstrate a tendency for the gas produced to ignite spontaneously. Substances are assigned to Packing Group II if they do not meet the criteria for Packing Group I and they react readily with water with a rate of flammable gas evolution that is equal to or greater than 20 L/kg. Substances are assigned to Packing Group III if they do not meet the criteria for Packing Group I or II and they react slowly with water with a rate of flammable gas evolution that is greater than 1 L/kg.

To learn more about IATA Dangerous Goods Regulations visit our IATA DGR Online Training Certification Courses web page.