An external water spray system (EWSS) is a domestic external fire sprinkler system designed to protect homes from bushfires and wildfires.
The types of systems vary greatly from a single impact sprinkler placed on a roof, systems installed during construction with sprays on all windows and doors, and small sprays damping gutters[citation needed].
Usage depends on type of risk and belief of effectiveness.
Copper piping is used to withstand high temperatures that may be experienced during a fire front or for higher reliability[citation needed] for in ceiling installations.
External PVC piping is used where failure with exposure to high radiant heat is acceptable[citation needed], as at the time the system is considered have "done its job".