Indoor sprinkler system can dampen fires fast

HOME WORK

November 21, 1992|By Karol V. Menzie and Randy Johnson

It's the wave of the future. Or at least the sprinkle.

A growing number of states -- Maryland is one -- are passing laws that require heat-activated automatic sprinkler systems in some residential construction. Single-family detached houses usually aren't included; multi-family units are.

Town houses generally are included. The Maryland law calls a town house "a single-family dwelling unit constructed in a horizontal series of attached units with property lines separating the units."

However, in some cases, local jurisdictions are passing their own, more stringent, laws governing sprinkler installation. In some cases that's going to mean that any one- or two-family attached dwelling that undergoes substantial rehab will have to have a sprinkler system.

The requirement is usually tied to the date of obtaining a building permit -- that is, anyone who obtained a permit before the date specified in the law doesn't have to comply.

The only way to find out if a house you're working on requires such a system is to check with the local jurisdiction.

There are different interpretations of the term "new construction." Some national building codes specify that any dwelling that undergoes more than 50 percent reconstruction is a "new" building that requires sprinklers. But some jurisdictions consider only the date of the original building permit.

But do you need to worry about fire?

Ken Lehn, regional manager for the National Fire Sprinkler Association, a trade group, said, "We lose about 5,000 to 6,000 people a year" in fires; about 80 percent of those people are in residential situations.

But figures from Operation Life Safety, a unit of the International Association of Fire Chiefs in Washington, show that between January 1983 and March 1992, in single-family, sprinkler-equipped dwellings across the country, there has been only one fire fatality.

Mr. Lehn said the real advantage of sprinklers is how quickly they respond to fires. Heat rises; that's why sprinklers are in the ceiling. Most are set to activate when air temperatures in their vicinity reach between 135 and 165 degrees, he said. Fire fighters call that the "incipient stage" -- just beyond smoldering into the first flames.

Even where it's not required, Mr. Lehn said, rehabbers might want to consider a sprinkler system.

People are concerned about sprinklers going off accidentally, and water damage whenever they go off.

"All the sprinklers in a building don't go off" when a fire is detected, Mr. Lehn said. "In a typical residential installation, with maybe 20 sprinklers, only one, or maybe two, will go off." The water discharge rate varies from model to model, he said, but it's usually around 18 gallons per minute. "If the fire department came in, it would be 100 gallons per minute or more."

fTC Industry research indicates that the chance of sprinklers going off because of a manufacturing defect is one in 16 million per year in service.

The biggest consideration in installing a residential system is the water supply, Mr. Lehn said. Most houses with municipal water have no problems, though in the case of older houses, the water line to the house may need to be larger -- some systems may require 1-inch pipes.

Sprinkler systems can't be installed with wells as the water source, Mr. Lehn said, but wells can be used to fill a self-contained, water-supply tank that feeds the sprinklers.

According to the sprinkler association, the cost of a system should be between $1 to $2 per square foot of building area. A self-contained water supply tank costs about $2,000, Mr. Lehn said. Changing a water-service line could cost less than $500 in a city rowhouse; if the pipe has to run a lot farther from the main to the house, the cost would be higher.

Next: Creative design solutions.

Mr. Johnson is construction manager for Neighborhood Housing Services of Baltimore. Ms. Menzie is a home writer for The Sun.

If you have questions, tips or experiences to share about working on houses, write to us c/o HOME WORK, The Sun, 501 N.

Calvert St., Baltimore 21278. Questions of general interest will be answered in the column; comments, tips and experiences will be reported in occasional columns.

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