1. If steel drums containing n-hexane rupture and produce a vapor concentration ranging from 20% to 45% by volume in air, is the vapor likely to ignite if exposed to an ignition source at 320F (160C)?

2. Describe the extent to which water may be used effectively to extinguish a fire involving n-hexanes inside a drum.

3. DOT-3E1800 is marked on a steel cylinder when its gauge pressure is 1610 psi at 70F (21C). Is this cylinder likely to rupture during a fire if the temperature of its contents rises to 300F (149C)?

4. Why is the rupture of a steel cylinder containing compressed helium gas gravely hazardous, despite the fact that helium is a nonflammable gas?