Sprinkler heads are held closed until heat activates them. Only the sprinkler heads near the fire open, spraying water on the fire to extinguish it or control it and keep it from spreading.
Sprinkler heads operate quickly to minimize the threat from heat, flames and toxic smoke.
This includes houses, apartments, mobile homes, hotels, motels, dormitories, etc. Sprinklers have been used for years in commercial and industrial buildings and the record is almost as good. More than 6,000 people die in fires in the United States each year. Sprinklers could save thousands of these people. In fact, as many as 90 percent of the deaths in residential fires could have been prevented by using sprinkler systems.