2.7.2. Classification criteria
2.7.2.1. Powdered, granular or pasty substances or mixtures (except powders of metals or metal alloys — see 2.7.2.2) shall be classified as readily combustible solids when the time of burning of one or more of the test runs, performed in accordance with the test method described in Part III, sub-section 33.2.1, of the ►M4 UN RTDG ◄ , Manual of Tests and Criteria, is less than 45 seconds or the rate of burning is more than 2,2 mm/s.
2.7.2.2. Powders of metals or metal alloys shall be classified as flammable solids when they can be ignited and the reaction spreads over the whole length of the sample (100 mm) in 10 min or less.
2.7.2.3. A flammable solid shall be classified in one of the two categories for this class using Method N.1 as described in 33.2.1 of the ►M4 UN RTDG ◄ , Manual of Tests and Criteria in accordance with Table 2.7.1:
Table 2.7.1
Criteria for flammable solids
|
Category |
Criteria |
|
1 |
Burning rate test Substances and mixtures other than metal powders: (a) wetted zone does not stop fire and (b) burning time < 45 seconds or burning rate > 2,2 mm/s Metal powders burning time ≤ 5 minutes |
|
2 |
Burning rate test Substances and mixtures other than metal powders: (a) wetted zone stops the fire for at least 4 minutes and (b) burning time < 45 seconds or burning rate > 2,2 mm/s Metal powders burning time > 5 minutes and ≤ 10 minutes |