Abstract: A unique fire protection system for the exterior, although adaptable to the interior, of mobile trailers, such as campers, mobile homes, cargo trailers, and the like, consisting of a loop of tubing mounted around the perimeter of a mobile trailer roof top with a series of spray nozzles affixed therealong to spray a fire extinguishing solution, such as water, carbon dioxide, a mixture of both, or the like, over the top of the trailer roof and downwardly on all four sides of a trailer. Two feed lines are provided into the fire sprinkling system, the input end of one feed line being provided with a water hose connector and shut-off valve and the input end of the other feed line being directly attached to a pressurized carbon dioxide tank also provided with a shutoff valve, and with each feed line being provided with a check valve to permit flow of water or carbon dioxide into the fire extinguishing system and so as to prevent backflow of the water or carbon dioxide.