Piping and Hydrant
By a wide margin, wet pipe sprinkler systems are installed more often than all other types of fire sprinkler systems. They also are the most reliable, because they are simple, with the only operating components being the automatic sprinklers and (commonly, but not always) the automatic alarm check valve. An automatic water supply provides water under pressure to the system piping.
A fire hydrant is an active fire protection measure, and a connection point by which firefighters can tap into a water supply.To prevent casual use or misuse, the hydrant requires special tools to be opened, usually a large wrench with a pentagon-shaped socket. Vandals sometimes cause monetary loss by wasting water when they open hydrants. Such vandalism can also reduce municipal water pressure and impair firefighters' efforts to extinguish fires. Sometimes those simply seeking to play in the water remove the caps and open the valve, providing residents a place to play and cool off in summer. However, this is usually discouraged as residents have been struck by passing automobiles while playing in the street in the water spray. In spite of this, some US communities provide low flow sprinkler heads to enable residents to use the hydrants to cool off during hot weather, while gaining some control on water usage. Most fire hydrants in Australia are protected by a silver-coloured cover with a red top, secured to the ground with bolts to protect the hydrant from vandalism and unauthorized use. The cover must be removed before use.