All Smoke Alarms Not Created Equal
Knowing the different specialities of smoke detectors may save your life.
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.
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.
