KREM-TV Story on Photoelectric vs. Ionization Smoke Detectors

From Krem.com

Click Here for Video

SPOKANE -- Smoke detectors may look the same, but after KREM 2 News put several of the safety devices to the test, we found one type performs much better in certain types of fires.

There are two basic types of smoke detectors: ionization, and photoelectric, both labeled clearly with either an "I" or a "P" on the packaging and on the back of the device. Ionization smoke detectors are what most people have in their homes.

But one type is better at detecting smoke from certain types of fires, and can provide life-saving minutes.

KREM 2 News tested four different smoke detectors.

To find out which works better, an experiment was set up at the Spokane Fire Department training center. Four smoke detectors were tested -- one photoelectric, one ionization, a cheaper verson of an ionization, and a "dual sensor" smoke detector with both kinds of technology.

Since there are different types of fires, a smoldering fire was first created, like the kind made from a cigarette burning through a chair. These fires can be especially deadly because they're quiet, and no major flame to startle the victim. Smoke can overcome them before they get out.

All four smoke detectors were placed in the room with the smoldering fire. After 31 minutes and 45 seconds the photoelectric smoke detector was first to sound. Twenty seconds later the detector with both photoelectric and ionization sensors went off. Finally, more than 40 minutes after the fire was started the cheaper ionization detector went off, followed closely by the more expensive ionization detector.

Spokane Fire Department Public Education Officer Jan Doherty said the test mirrors the exact same results from other tests around the country -- that photoelectric smoke detectors are quicker to detect a smoldering fire.

Next, firefighters created the raging type of of fire with an open flame. It did not take long for all four of the smoke detectors to start sounding, but this time the ionization detectors sounded just a few minutes before the photoelectric detectors.

The National Institute of Standards and Fire Prevention Associated have done extensive testing on smoke detectors, and found either photoelectric or ionization technology provide adequate escape time from most types of fires, but recommend both types for maximum protection.