By Mike McClintock
Special to The Washington Post
Thursday, June 16, 2005
Overhead sprinkler systems have protected public buildings from fire for more than a century. About 20 years ago, a simpler, sleeker, less expensive counterpart of the clunky commercial systems became available for private houses as well.
But the word hasn't gotten out, going by a recent survey of consumers by the National Fire Protection Association ( http://www.nfpa.org ). It found that while 92 percent thought sprinklers were effective in fighting fires, 48 percent had no idea there was a residential version.
Currently, less than 1 percent of new houses have fire-suppressing sprinkler systems built in, even though the association says they reduce the chance of dying in a fire (and property loss) by one-half to two-thirds.
How sprinkler systems work
The idea is logical and simple: Instead of waiting for the fire department with its high-volume hoses, fight the fire automatically, as soon as it starts, with water that's already there.
A sprinkler system uses your household water supply but distributes it to rooms through a separate network of plastic pipes. The pipes are hidden and the sprinkler heads are flush-mounted so your house doesn't look like a factory. Many systems also have thin cosmetic covers, blown off when the sprinkler discharges, which blend in with the ceiling and make the heads basically unnoticeable.
The system has the same pressure as your tap water, though in unusual cases a backup storage tank and pump are needed. The water is always ready to flow but stopped at each sprinkler head by a temperature-sensitive plug. It releases at about 160 degrees Fahrenheit.
The initial, automatic spray may extinguish the blaze, but even when it can't, sprinklers slow the growth and spread of a fire. The Home Safety Council points out that the nearly immediate reaction can provide the time you need to escape safely and call the fire department.
Sprinklers aren't triggered by smoke -- a common misconception that has hurt sprinkler sales. Another is the idea that when one head is triggered, every other head in the system starts spraying. A building-wide deluge makes for funny scenes in movies, but that's not the way it works.
If a fire spreads, adjacent heads will only release water as their plugs give way in the heat. But multi-head releases are unusual, according to the Home Fire Sprinkler Coalition ( http://www.homefiresprinkler.org ). It says that almost all fires are contained by the operation of just one sprinkler head.
Many people also think sprinkler systems may flood the house and create more damage than the directed sprays of fire hoses. Actually, it's the other way around.
A residential fire sprinkler uses an average of 341 gallons of water to control a fire. Firefighters, on average, use 2,935 gallons -- mainly because the fire is larger by the time they arrive.
Manufacturers say reduced water damage is a major source of savings with sprinkler systems -- usually in addition to a reduction in home insurance costs.
In a typical scenario, the fire department will check the building even if the sprinkler has extinguished the blaze. Then the sprinkler water supply is turned off until you have the activated sprinkler head replaced.
Cost and effectiveness
Those unusually precise water-use statistics come from the best of all proving grounds for sprinkler systems, Scottsdale, Ariz. The city has been an ideal source of practical information since 1986 when an ordinance went into effect requiring sprinklers in all new residential construction.
The NFPA says that more than 50 percent of the homes in Scottsdale (over 40,000) are now protected with sprinklers. It makes for a huge data base -- and a strong case for sprinklers.
· Data collected by the city fire department indicate that the systems have saved 13 lives and prevented more than $20 million in property loss.
· Initially (from 1986 to 1992), the average property loss from fire in homes with sprinklers was $2,665, and $17,067 in homes without them. During the last three years, says the NFPA, average fire loss in the homes with sprinklers was $2,166, compared with $45,019 in homes without them.
· Over 90 percent of fires in Scottsdale houses with sprinkler systems were contained with the activation of one sprinkler head.
When it comes to price (another potential stopper for consumers), most sprinkler groups say contractor-installed systems run just over 1 percent of the cost of construction, or approximately $1 to $2 per square foot of living space. Retrofits in existing homes are more, often $2 to $3 a square foot.
In Scottsdale, typical installed costs are about half the national average -- a result of competition among many installers in a market where sprinkler installations are not optional.
But actual cost depends not only on the size of the house, but also on its layout, framing plan and whether the sprinklers are tied in to an alarm system. Most installations have a flow switch that can activate a stand-alone audio or visual alarm. But sprinklers can also be tied in to a central security system.
Finally, fire safety groups such as the NFPA, which recommends the systems, remind consumers that sprinklers should be used in addition to, not instead of, smoke detectors.
