Time is essential in the control of fire. Automatic sprinkler systems are one of the most reliable methods available for controlling fires. Today's automatic fire sprinkler systems offer state of the art protection of life and property from the effects of fire. Sprinkler heads are now available which are twenty times more sensitive to fire than they were ten years ago.
A sprinkler head is really an automatic (open once only) tap. The sprinkler head is connected to a pressurised water system. When the fire heats up the sprinkler head, it opens at a pre-set temperature, thus allowing pressurised water to be sprayed both down onto the fire and also up to cool the hot smoky layer and the building structure above the fire. This spray also wets combustible material in the vicinity of the fire, making it difficult to ignite, thereby slowing down or preventing fire spread and growth.
When a sprinkler head operates, the water pressure in the system drops, activating an alarm which often automatically calls the fire service via a telephone connection.
Some people say sprinklers cause a lot of water damage. As has been explained, only those sprinkler heads heated by the fire operate; all sprinklers in a building do not operate at once. Usually non-fire water damage only occurs if the occupants carelessly damage the system. Firefighters use much more water than a sprinkler system. The combined damage from a fire and the water used by firefighters dramatically exceeds that likely from a properly installed sprinkler system.
Because, historically, complete extinguishment of fires has not been achieved, it is traditional to consider that sprinklers only control fire growth until intervention occurs by the fire service. Today, some sprinkler systems are designed for early suppression and are considered to have failed if they do not extinguish the fire.
Sprinkler systems are usually installed in high or large buildings and high fire hazard occupancies. Statistics show that in a majority of cases where sprinklers are installed the fire has been controlled by one sprinkler head alone.