Transportation of Dangerous Goods Regulations — 2.22
2.22 (1) Substances included in Class 4.1, Flammable Solids, are included in one of the following packing groups: (a) Packing Group I, if the substances meet the criterion in subparagraph 2.21(1)(a)(iii), except that substances that have one of the following UN numbers are included in Packing Group II: UN2555, UN2556, UN2557, UN2907, UN3270, UN3319 or UN3344; (b) Packing Group II, if (i) the substances meet the criteria for inclusion in Class 4.1 in subparagraph 2.21(1)(a)(iv) or (v), except that substances that have one of the following UN numbers are included in Packing Group III: UN2956, UN3241 or UN3251, (ii) in tests referred to in section 33.2.1 of Part III of the Manual of Tests and Criteria for readily combustible solids, excluding metal powders, the burning time of the substances is less than 45 seconds and the flame passes the wetted zone, or (iii) in tests referred to in section 33.2.1 of Part III of the Manual of Tests and Criteria, for readily combustible solids that are powders of metals or metal alloys, the zone of reaction of the substances spreads over the whole length of the sample in 5 minutes or less; or (c) Packing Group III, if (i) in tests referred to in section 33.2.1 of Part III of the Manual of Tests and Criteria, for readily combustible solids, excluding metal powders, the burning time of the substances is less than 45 seconds and the wetted zone stops the flame propagation for at least 4 minutes, (ii) in tests referred to in section 33.2.1 of Part III of the Manual of Tests and Criteria, for readily combustible solids that are powders of metals or metal alloys, the zone of reaction of the substances spreads over the whole length of the sample in more than 5 minutes but not more than 10 minutes, or (iii) the substances are solids that are liable to cause fire through friction. (2) Substances included in Class 4.2, Substances Liable to Spontaneous Combustion, are included in one of the following packing groups: (a) Packing Group I, if the substances are pyrophoric solids or liquids; (b) Packing Group II, if the substances are self-heating substances that give a positive result, as determined in accordance with section 2.4.3.2 of Chapter 2.4 of the UN Recommendations using a 25 mm sample cube at 140°C; or (c) Packing Group III for all other substances. (3) Substances included in Class 4.3, Water-reactive Substances, are included in one of the following packing groups: (a) Packing Group I, if the substances (i) react vigorously with water at ambient temperatures and demonstrate a tendency for the gas produced to ignite spontaneously, or (ii) react readily with water at ambient temperatures so that the rate of evolution of flammable gas is greater than or equal to 10 L/kg of substance over any one minute; (b) Packing Group II, if (i) the substances react readily with water at ambient temperatures so that the rate of evolution of flammable gas is greater than or equal to 20 L/kg of substance per hour, and (ii) the criteria for inclusion in Packing Group I are not met; or (c) Packing Group III, if (i) the substances react slowly with water at ambient temperatures so that the rate of evolution of flammable gas is greater than or equal to 1 L/kg of substance per hour, and (ii) the criteria for inclusion in Packing Group I or II are not met. SOR/2017-137, s. 22