All Smoke Alarms Not Created Equal

Jan.10, 2008 — -- January is the deadliest month for house fires and fire-related deaths in America, according to the National Fire Protection Association. While many households have smoke detectors, many consumers are unaware of the type of device they are using, which could make a huge difference in an emergency.

Two types of smoke detectors exist: an ionization alarm and a photoelectric alarm. The two have varying response times in specific fire situations.

The National Institute of Standards and Technology concluded that ionization alarms provide a "better response to flaming fires," while photoelectric alarms provide "considerably faster response to smoldering fires," after testing thousands of alarms for two years.

However, 90 percent of U.S. homes have the ionization alarms, which usually are cheaper than photoelectric smoke detectors.

Putting Them to the Test

To test how the smoke detectors would act in a potential emergency, ABC News along with Montgomery County, Md., fire and rescue ignited a house fire, similar to what would happen if a candle tipped over in a residence.

An ionization, a photoelectric and a combination smoke detector sat above the blaze. A mere 44 seconds after the flaming fire began, the ionization alarm was the first to sound. As the flames grew and licked dangerously close at the arm of a chair located in the room, the other alarms took more than double the time to sound off.

After two minutes and 38 seconds, the photoelectric alarm went off and the combination alarm sounded soon afterward — two minutes and 59 seconds after the fire began.

A two or three-minute delay can make a big difference in a fire emergency, especially since the blaze doubles in size every minute.

In another experiment, ABC News' Buffalo affiliate ignited a slow, smoky and smoldering fire with a cigarette in a sofa cushion. In that case, the photoelectric alarm went off in less than four minutes, with the combination alarm sounding four seconds behind it.

The ionization smoke detectors took 11 minutes and 41 seconds before they went off — nearly eight minutes later than the photoelectric device — even though smoke was pouring right over the detectors.

It's an important distinction because flames are not most likely to kill in a fire.

"In almost all cases, the smoke is the issue. The smoke is silent but deadly," said Montgomery County Md., Fire and Rescue chief Tom Carr.

Another issue, which may make blazes today more dangerous, is the fact that 30 years ago, residents could count on 17 minutes to evacuate. Today, modern furnishings burn much faster and people don't have nearly as much time to get out, according to NIST.

"You really only have three minutes to get out of the building in the worst situation. You don't want to press your luck. You want to respond immediately," said Bill Grosshandler, of NIST

Protecting Yourself

The NFPA recommends people replace their alarms every decade and install both types of technology for the earliest possible warning. Here are other ways to protect your family:

The most important safety advice about smoke alarms is to have them and keep them in good working order. According to the National Fire Protection Association, nearly all U.S. homes have smoke detectors today, but in one out of every five homes, those detectors are not working.

Buy brand new smoke alarms every 10 years or sooner. They lose their sensitivity over time. While you're at it, buy some ionization and some photoelectric smoke detectors.

Get detectors for every level of your house, and preferably every room, especially inside bedrooms.

If possible, buy alarms that are interconnected, so if there's a fire in one part of your house, the alarm there automatically triggers all the other alarms in your house.

Change the batteries when you change your clocks and test your smoke alarms once a month by pushing the button.

It's best to install most smoke alarms on your ceilings rather than walls, because smoke rises, and that gives you the earliest possible warning. Follow the manufacturer's directions for optimum placement.

To avoid nuisance alarms, keep smoke detectors a reasonable distance away from cooking appliances, but still close enough to warn you, since cooking is the number one cause of household fires.

You should develop a fire evacuation plan for your home and practice it. Keep in mind that children and the elderly often sleep through smoke alarms. So your plan should include taking the time to wake them and get them out. You might want to test your smoke alarms overnight when family members are sleeping and see if they wake up.

The old standard was to install a smoke alarm outside each sleeping area. Now experts recommend also installing one on the ceiling of each bedroom, because the earlier you get the warning, the more time you have to get out.

For more information visit the National Fire Protection Association's Web site.