The numbers used on flammable material placards required by the US DOT are the same as those on the NFPA fire diamond.

• A. Not sure
• B. Both
• C. True
• D. False

Answer: (D)

The numbers on DOT placards and the NFPA fire diamond come from different labeling systems that convey different information. DOT placards indicate the hazard class of the material (numbers 1 through 9 correspond to categories like explosives, gases, flammable liquids, etc.). The NFPA 704 fire diamond, on the other hand, uses a 0–4 scale in three separate sections (health, flammability, reactivity) to rate how dangerous the material is in each dimension, plus a white section for special hazards. Because one system labels the category and the other rates hazard severity in multiple dimensions, their numbers aren’t directly the same or interchangeable. So the statement is false.