Deluge systems deliver large quantities of water, over a large area, in a relatively short period of time. They are commonly used in fixed fire protection systems whose pipe system is empty until the deluge valve distributes pressurized water from open nozzles or sprinklers.
Deluge systems contain more components and equipment than wet pipe and dry systems. So for that matter, they are more complex. Detection systems can include heat, smoke, ultraviolet (UV), or infrared (IR).