Can You Hear The Smoke Alarm Now?-Environmental Health & Safety - Carnegie Mellon University

Monday, January 14, 2013

Can You Hear The Smoke Alarm Now?

Many of you may have seen the Rossen report on the Today show which aired on October 3rd. The report pertained to smoke alarms and how long it took for an ionization smoke alarm to activate during an experiment conducted by Dr. Don Russell a scientist from Texas A&M University. I am not writing to refute Dr. Russell’s findings, but rather to explain the different types of smoke alarms that are available and how they function.

Technologies within a smoke alarm can differ. An ionization smoke alarm is designed to detect a fire involving fast moving flames. A photoelectric smoke alarm is designed to detect a fire that is smoky, smoldering, and slow burning. For maximum protection fire experts recommend the use of both types of technologies or a dual sensor smoke alarm, which incorporates the features of both technologies. Ionization smoke alarms are most prevalent in homes because they are the least expensive. Typically an ionization smoke alarm can cost from $5.00 to $15.00, while a photoelectric smoke alarm can cost from $11.00 to $20.00 and a dual sensor smoke alarm can range from $20.00 to $25.00.

So which smoke alarm is more effective?
To answer this question accurately we should take a look at what is not discussed in this Rossen report. Smoke is more lethal now than ever before due to the change in household products and furnishings to plastics, laminates and synthetics. The combustion phases of these fires produce a more toxic environment, one where the off gassing of these products will generate lethal levels of HCN and CO. Hydrogen cyanide and carbon monoxide attack the blood and organs of the body. The majority of fire-related fatalities are not caused by fire but rather smoke inhalation. For more information on smoke alarms visit www.nfpa.org/smoke alarms.

By: Richard Caruso, rmcaruso@andrew.cmu.edu, 412-268-9404