How Do Fire Sprinkler Systems Work?

Fire sprinklers are fire-safety devices that release a spray of water when they detect a fire. The spray is meant to extinguish or slow down a fire. Sprinklers are almost always found in ceilings.

Sprinklers use a device which activates them when they reach a certain temperature. These are either a fusible substance, such as Wood's Metal, a substance that will reliably melt, or a glass bulb that contains a liquid that will burst the bulb when heated. The result is that any of these activators will be destroyed when heated to a certain level, allowing water pressure to push out a plug and causing water to flow out through the sprinkler.

Unlike what people have been led to believe by films and television, all the sprinklers in a given room or building do not go off all at once just because one of them do in a typical system. Automatic sprinklers are designed to go off individually and based upon their strict local conditions. Only the open orifice types go off all at once, and then only when they are of arranged in a "deluge" system. The open orifice sprinkler is identical to the normal, automatic sprinkler, except the automatic heat-sensitive element is removed. Fire is detected outside the sprinkler itself.

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