BARRE, Vt. — When a fire killed a mother and four children here in 2005, there was something peculiar: As firetrucks arrived, the apartment was full of smoke and had a working smoke detector, but it wasn’t sounding its alarm.
Months later, Fire Chief Peter John found out why. The smoke detector was an ionization smoke detector — like those in 90 percent of American homes. They have been shown to react slowly in the presence of smoldering fires.
Now, John and others have signed onto a campaign to publicize the benefits of photoelectric smoke detectors, which they say sense smoldering fires better. Deputy Fire Chief Joseph “Jay” Fleming of the Boston Fire Department says he has been trying to tell industry groups and the government about them for years.
“My department’s on that mission, and I’ve joined right in on it,” John said.
Fleming estimates that nationwide, up to a third of the more than 3,000 people a year who die in fires might have escaped if they’d had a photoelectric smoke detector, rather than an ionization smoke detector.
The 2005 Barre fire was an example: The fire smolders for hours, filling a dwelling with deadly smoke before an ionization detector goes off.
Fleming and his allies appear to be making progress, though not as much as he would like. In recent years, several national groups have come out with advisories saying that for the best protection, both kinds are recommended.
Photoelectric smoke detectors contain a light source and a light-sensitive electric cell. Smoke entering the detector deflects light onto the light-sensitive cell, triggering an alarm.
Ionizing sensors contain a small amount of americium-241, a radioactive material. It is used to set up a small electrical current between two metal plates which, when disrupted by smoke entering the chamber, sounds the alarm.
People on both sides of the debate are quick to say every home should have some type of smoke detector on every floor. The devices have cut residential fire deaths in half in the past 30 years.
John Drengenberg, manager of consumer affairs at Underwriters, told a Vermont Senate committee that his nonprofit product-testing firm now is recommending that people install both types.
Newer “combination” alarms on the market contain both photoelectric and ionization sensors, but Fleming said the combination detectors are easily set off by cooking fumes or steam from showers.
