For Flammable Solids other than metals, when burning time is less than 45 seconds and the flame passes the wetted zone, to which group is it assigned?

• A. Class 4.1
• B. Packing Group III
• C. Self-reactive substance
• D. Packing Group II

Answer: (D)

The key idea is how flammable solids are grouped by packing groups based on how they burn in a standard test. For flammable solids, if the material flames up quickly and, during the test, the flame can propagate across a wetted portion of the sample (the wetted zone) with a burning time under 45 seconds, it indicates a moderate level of hazard. That situation, by the rules, places the substance in Packing Group II. Packing Group II reflects more hazard than Packing Group III but less than Packing Group I.

So this specific burning behavior—quick burn time and the flame crossing the wetted zone—fits Packing Group II. The option describing the overall class (flammable solids) isn’t the packing group, and Packing Group III would apply when the burning is slower or the flame doesn’t pass the wetted zone, indicating a lower hazard. Self-reactive substances are a different category altogether.