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)? If the steel drums containing n-hexane rupture, will its vapor initially accumulate in low areas or diffuse upwards? Then, describe the extent to which water may be used effectively to extinguish a fire involving n-hexanes inside a drum.