FM Global firefighters watch a controlled burn of a typical, unsprinklered living room at their facility in Glocester. There is a campaign in Congress to mandate sprinklers in newly constructed houses.

The Providence Journal / Steve Szydlowski

GLOCESTER — It took local carpenters nearly a week to build two living rooms for the insurance company FM Global. Each featured a recliner, couch, family photos and a 37-inch flat-screen TV.

On Thursday, FM Global set them on fire.

The company will spend about $250,000 on the experiment, designed to help researchers better understand how house fires affect the environment.

One room — a 15-by-20-foot box of studs, insulation and sheetrock — burned quickly. A door buckled, the glass shattered and the TV melted.

But the other room, which included a sprinkler in the ceiling, burned much slower. After 10 minutes, the blaze was nearly out, with the damage confined to a corner. The sprinkler sprayed more than 200 gallons of water into the room, said Chris Wieczorek, an FM Global senior research specialist.

Doused fires mean less smoke and fewer charred items bound for the landfill, say company officials.

But how beneficial are residential sprinklers? Do they justify the cost, which can add thousands of dollars to a house’s price tag?

“Is the benefit small or large?” said Louis Gritzo, vice president and manager of research at FM Global “That’s what we plan to measure.”

The experiment comes just days before Fire Prevention Week — and amid a national debate over whether builders should install sprinklers in new houses.

“Sprinklers are proven to save lives and protect property,” said Gary Keith, chairman of the Home Fire Sprinkler Coalition, at yesterday’s demonstration. But they also provide environmental benefits — “benefits we will only be able to prove through scientific study.”

Nearly 50 officials, some from trade organizations and regional fire departments, joined FM Global officials during the four-hour presentation.

They donned white hardhats and plastic safety glasses to tour FM Global’s 1,600-acre research campus in West Glocester. Although nationwide some builders have balked at safety requirements –– sprinklers could price some people out of a home, they say –– those who gathered yesterday favored them.

Home sprinklers contain fires and allow families to get out of burning buildings quickly, said Rhode Island Fire Marshal John Chartier. “Nationally, we are losing folks in home fires.”

Rhode Island officials will tackle the issue this spring. A proposed new fire code would require builders to add sprinklers to new houses. Older houses would be exempt, he said. “I’m optimistic it will pass. But I’m sure there will be a lot of debate.”

The insurance company will issue a full report on the living-room burns early next year.

But FM Global manager Denny Anderson didn’t need much persuasion. He watched as the sprinkler dampened the first fire quickly.

“The sprinkler won,” he said.

pdavis@projo.com