Fire Fighting 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 correctly.  As soon as the firefighter opens the hydrant, water will gush out, and sensors will detect a drop in pressure in the system. This pressure drop will trigger the fire pumps to turn on and start pumping water at a tremendous flow rate.

A sprinkler is a nozzle attached to a network of pipes, and installed just below the ceiling of a room. Every sprinkler has a small glass bulb with a liquid in it. This bulb normally blocks the flow of water. In a fire, the liquid in the bulb will become hot. It will then expand, and shatter the glass bulb, removing the obstacle and causing water to spray from the sprinkler. The main difference between a hydrant and a sprinkler is that a sprinkler will come on automatically in a fire. A fire hydrant has to be operated manually by trained firefighters – it cannot be operated by laymen. A sprinkler will usually be activated very quickly in a fire – possibly before the fire station has been informed of the fire – and therefore is very effective at putting out a fire in the early stages, before it grows into a large fire.  For this reason, a sprinkler system is considered very good at putting out fires before they spread and become unmanageable.