More sand Guv?
Not usually an onerous duty, Fire Piquet was considered a reasonable 'sleeping duty', providing it didn't go all Pete Tong and you didn't have to put out fires.
The fire-fighting equipment (circa 1970s & '80s) consisted of a two-wheeled wooden hand cart (flammable), several lengths of canvas hose (flammable), 4 fire buckets that were filled with 99% fag ends 1% sand (flammable), a foam fire extinguisher (u/s) and 6 fire beating brooms made entirely of dry wood (flammable).
However, you may do so if you feel safe in doing so and are confident in your knowledge of the fire fighting equipment at your disposal. Your obligations in reporting any fire are not changed by these regulations, and you will shout "Fire, Fire, Fire!" and report it by telephone if one is available.