Photo finish: How to find the right detector

So you've decided to ditch those ionization smoke detectors in your house, and keep your family safe with photoelectrics. But then you think, "How do I know what kind I have?"

According to Boston Deputy Fire Chief Jay Fleming, there are several ways to identify the type of detector in your house: if you see the words "radioactive" or "Americium 241" anywhere on the outside or back of the device, it's an ionization model.

But even if there are no printed clues, you can still be fairly sure, says Adrian Butler, cofounder of the Australia-based World Fire Safety Foundation.

"The chances are 99 percent that what you have is an ionization smoke alarm," he says, "because if you're asking the question, it means you haven't made a conscious effort to get a photoelectric."

Indeed, Fleming agrees that the vast majority– well over 90 percent– of smoke detectors in American homes are ionization models. As detailed in last week's cover story, "Alarming: Most smoke detectors don't detect deadly smoke," the two types look nearly identical, but they work in starkly different ways.

Ionization detectors use a small amount of radioactive material to detect combustion particles and are about half a minute faster at detecting the small or invisible particles emitted by flaming fires. Photoelectrics, by contrast, use a beam of light to detect smoke, and they can be 30, 40, 50 minutes (or more) faster at detecting the larger particles given off by a smoldering fire, the type most likely to kill you at night while you're sleeping.

The Hook's June smoke detector test, supervised by Fleming and local fire officials, supported the assertion that ionizations might fail– with devastating consequences– to detect a smoldering fire. More than an hour after a couch had been ignited with a soldering iron, and long after the room filled with acrid smoke, the ionization detectors in our test remained silent.

"They're not smoke detectors," says Fleming. "They're fire detectors."

Both Butler and Fleming believe that at least 10,000 people have died in American house fires in the past 15 years because they had an ionization detector that either didn't trigger until it was too late for residents to escape or didn't trigger because it had been disabled because of false alarms. According to one study, the devices' susceptibility to innocuous triggers such as shower steam and toast makes them eight times more likely than photoelectrics to be disabled.

The evidence of ionization's failures is strong enough to have convinced legislators in Massachusetts and Vermont to sign laws this year requiring only photoelectrics in new construction. (In Vermont, the law was instituted following a fire in which a mother and four children perished despite ionization detectors that had not yet triggered when firefighters arrived at the heart-breaking scene.)

So, now that you've decided to update your smoke detectors, where can you go to find photoelectrics? Not many places, as it turns out.

Of the locally owned hardware stores, only Martin Hardware on Preston Avenue currently carries that type. That, says owner Mike Jarrell, is thanks to customer requests following the Hook's first article on the subject, the April 17 cover story "Smoldering truth: Ashley Mauter and a shocking fact about smoke detectors."

"We sold all we got in," says Jarrell, who was preparing another photoelectric order as this issue went to press.

Both Wal-Mart and Kmart had at least one photoelectric in stock, although they were difficult to spot among the ionization models.

Surprisingly, Lowe's– by far the largest hardware store in the Charlottesville area– doesn't stock a single photoelectric. (Most can be picked out by a "P" boldly printed on the packaging.) Lowe's carries a variety of ionization models and several combination detectors, which use both technologies. That's the type distributed in both the city and the county's free smoke detector programs, and it's the type endorsed by the International Association of Fire Chiefs. But Fleming points out they are more costly than photoelectric only– and more importantly, they are vulnerable to false alarms.

"Photoelectric alone gives time to escape in either type of fire scenario," says Fleming.

If local stores either don't stock them or are out of stock, another option is to buy online., for instance, has several photoelectrics for around $15.

If you install photoelectrics, you can either leave your ions in place or remove them. But don't put them straight into the trash because they contain radioactive material. Considered hazardous waste, they're accepted twice a year at the Ivy Landfill, and the next hazardous waste day will happen sometime this fall, according to Bruce Edmonds, recycling and litter manager for Rivanna Solid Waste Authority.

One thing everyone can agree on: don't toss the old ionizations until you have the new photoelectrics ready to install.