The Investigators: Dual-Sensor Smoke Detectors - WMC Action News 5 - Memphis, Tennessee

The Investigators: Dual-Sensor Smoke Detectors

(WMC TV) - In an exclusive interview with Action News 5, Tennessee's fire marshal recommended dual-sensor detectors as the best choice in household smoke detectors.

"The dual-sensor smoke alarms cost a little bit more, but in reality, you're getting the full protection," said Tennessee Fire Marshal Gary L. West.

Dual-sensor smoke alarms carry both types of smoke detection sensors:

* PHOTOELECTRIC:  "Photoelectric detectors are more designed for detecting smoldering fires," said Graham McBride, detector expert with State Systems (, a Memphis-based company that specializes in commercial fire protection systems.

"A photoelectric detector uses a light beam to detect smoke," McBride said.

* IONIZATION: "An ionization detector uses a radioactive element to ionize the air," McBride said. "It, in turn, detects small particles of smoke that are not visible to the naked eye.

"Ionization detectors do a better job of detecting flaming fires which contain smaller particles."

When the Action News 5 Investigators tested both types in May with the Memphis Fire Department, the ionization sensor detected a controlled burn inside a sealed, steel train car faster than the photoelectric sensor. Both were positioned at the same distance from the fire source and at the same height a smoke detector should be installed in a hallway.

During our research, we discovered tests performed in other states where a photoelectric sensor detected wispy, smoldering fires more quickly than an ionization sensor.

West said a combination of data supporting both types of detectors and the introduction of dual-sensor alarms to the consumer market a few months ago convinced him to officially recommend them.

McBride cautioned if you already own a working photoelectric or ionization smoke alarm, you don't have to purchase a dual-sensor alarm.

"Not necessarily," he said. "You are protected. You have smoke protection in your home. (But) having the dual-sensing technology, hopefully, would save lives. Hopefully, you would know about the fire a lot quicker."

West also recommended 10-year batteries, now available at most home improvement stores. Designed especially for smoke alarms, they guarantee a 10-year battery life. Their cost:  about $10 for a 2-pack.

"They, too, cost a little bit more, but not having to change the battery and letting the smoke detector protect you for ten years is very important," West said.

For cost comparisons, ionization smoke detectors average about $15. Photoelectric detectors run about $13. The dual-sensor detectors:  $23. 

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