A fire fighting system is probably the most important of the building services, as its aim is to protect human life and property, strictly in that order.
It consists of three basic parts:
a large store of water in tanks, either underground or on top of the building, called fire storage tanks
a specialised pumping system,
a large network of pipes ending in either hydrants or sprinklers (nearly all buildings require both of these systems)
A fire hydrant is a vertical steel pipe with an outlet, close to which two fire hoses are stored (A fire hydrant is called a standpipe in America). During a fire, firefighters will go to the outlet, break open the hoses, attach one to the outlet, and manually open it so that water rushes out of the nozzle of the hose. The quantity and speed of the water is so great that it can knock over the firefighter holding the hose if he is not standing in the correct way. As soon as the fire fighter opens the hydrant, water will gush out, and sensors will detect a drop in pressure in the system. This drop in pressure will trigger the fire pumps to turn on and start pumping water at a tremendous flowrate.