You never know when or where a fire will start in your home. What if you could have a firefighter stationed in every room 24 hours a day, ready to stop a fire the minute it broke out? That is what fire sprinklers are – instant firefighters. They are installed in the ceiling or high on a wall and are attached to the same water supply that feeds your home's plumbing fixtures. Residential fire sprinklers are small. In fact, they fit in so well that you have to point them out for people to notice them.
You already have water running throughout your home to sinks, showers, toilets and washing machines. Fire sprinklers use the same water to extinguish a fire. Average-sized rooms only need one sprinkler.
A sprinkler is similar to a hose nozzle because it breaks the stream of water into a fine spray. Water cannot spray until the heat from a fire activates the sprinkler. A metal seal over the waterway holds the water back. The cap is held in place by either a glass bulb or metal. Both are very rugged but are designed to break or melt in the high heat of a fire.
If the fire is so hot that the water from one sprinkler cannot cool it, the hot gases will reach the next nearest sprinkler. Then that sprinkler would open to stop the fire. This design of opening only when there is enough heat limits the number of sprinklers to what is needed to stop the fire. Fire records show that 93 percent of fires are handled by only one sprinkler. In the remaining cases, two sprinklers handled an additional four percent. It took three sprinklers to handle nearly all of the remaining three percent. Keep in mind that these figures include large warehouses storing highly combustible goods that generate tremendous heat. In these cases, more than one sprinkler may be necessary to spray enough water to stop the fire. In homes and apartments, it is rare to have more than one sprinkler operate, so the number of fires controlled by one sprinkler in residences is nearly 100 percent.
The water spray from the sprinkler cools the fire gases rising from the fire. When the cool spray reaches the burning material, it cools it to below its combustion temperature. Then it can no longer burn, and the fire goes out. Responding firefighters will shut off the sprinkler once they are sure that the fire is completely out.
Fire Sprinkler Facts
- Sprinklers save lives.
Sprinklers are one of the most effective fire safety devices ever invented. The National Fire Protection Association reports that people with smoke alarms in their home have a 50 percent better chance of surviving a fire. Adding sprinklers and smoke alarms increases your chances of surviving a fire to more than 97 percent.
- Sprinklers save property.
Residential fire sprinklers are designed to save lives, but because they control fires so quickly, they also reduce property damage. Fire reports show that property damage is nine times lower in homes where sprinklers are installed.
Will sprinklers leak?
Sprinklers and sprinkler piping are pressure-tested at two to three times higher than normal plumbing systems, which means the chance of a sprinkler leaking is actually quite small. Additionally, sprinkler pipes are not exposed to cold areas, which means they are protected from freezing.
Won't all the sprinklers in the room go off at the same time?
The heat from a fire will activate the nearest sprinkler. The sprinkler’s water quickly cools the hot fire gases, which typically eliminates the need to open the next nearest sprinkler. In the rare case that the heat is too much for the nearest sprinkler, it will open the next nearest sprinkler. The end result is that only the sprinklers necessary to stop the fire will operate.
Won't the water from a sprinkler create more damage than the fire?
One of the myths about sprinklers is that they will cause water damage. While this may seem logical (after all, they spray water), fire records show that the reverse is actually true. Here is why. A residential fire sprinkler sprays about only 10-18 gallons of water per minute and operates early in a fire to stop the burning. A hose used by firefighters flows ten times that amount, 175-200 gallons a minute. If sprinklers are not present, fires typically burn for an additional 10-15 minutes until firefighters arrive and begin spraying it with their hoses. Two things happen to cause more damage than sprinklers. First, more of your possessions have burned up before the firefighters intervened, and second, you have 10 times more water being sprayed at a very high pressure on what you have left.
The combination of the sprinkler's quick response, the smaller water flow and lower pressure significantly reduce water and property damage. Without sprinklers, the heat and smoke from a fire travel very quickly, damaging the furniture and possessions throughout the house. With sprinklers, the sprinkler nearest the fire will stop it before it can develop the damaging heat and smoke.
You can install an alarm to alert you when a sprinkler opens and water starts flowing. The alarm will also alert neighbors, and you can have it monitored by an alarm company so they can call the fire department if no one is around.