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When should I replace my smoke alarms?
Tuesday, October 2, 2018
Smoke alarms that are ten years old or more should be replaced. Although the alarm may sound when tested with the test button, that only indicates that the alarm sounding mechanism is operating properly, but the internal smoke-sensor device arrives at the end of its service life at 10 years.
Smoke Detectors Test The Air Continuously
Replacement is necessary because smoke alarms do not sit idle until a fire event activates them. They test the air continuously, around-the-clock. An alarm using ionization technology will have completed 3.5 million monitoring cycles in its ten year life, while a photoelectric type alarm will have been checking for smoke across a tiny beam of light continuously for 87,600 hours. As an alarm ages past the ten-year point, the likelihood of it responding quickly—or at all—to a fire event decreases and it is ready for retirement.
Photoelectric Alarms Recommended
When it’s time to replace your smoke alarms, most national fire safety organizations now recommend only photoelectric type alarms. Here’s what the International Association of Fire Fighters has to say on the subject:
“Research has demonstrated that photoelectric smoke alarms are more effective at warning of smoke from smoldering fires than ionization smoke alarms. With earlier warning, people have more time to escape a burning structure and call 911 sooner. Photoelectric smoke alarms also are less susceptible to nuisance alarms. To prevent nuisance alarms, citizens often disable smoke alarms, placing themselves, others in a home or building and fire fighters at greater risk. Photoelectric smoke alarms contain a light source and a light-sensitive electric cell. Smoke entering the detector deflects light onto the light-sensitive electric cell, triggering the alarm. These alarms are more sensitive to large particles given off during smoldering fires—the kind of fires that typically occur at night when people are asleep.
Ionization smoke alarms have a small amount of radioactive material, and establish a small electric current between two metal plates, which sound an alarm when disrupted by smoke entering the chamber. But the technology leads to a delayed warning in smoldering fires that can lead to greater loss of life among people and fire fighters in a burning structure as a result of a more developed fire. A delayed warning during a smoldering fire, especially at night, can incapacitate people who are sleeping and lead to death as fire spreads.
No home should be without a smoke alarm, and ionization alarms should continue to be used until a home can be equipped with photoelectric alarms.”
The importance of having functional smoke alarms in a home cannot be overstated. There are more than 300,000 house fires each year and, because more people die from inhaling toxic smoke than from burns, getting out of the house immediately at the first sign of smoke is life-saving.
For more information on smoke alarms and fire safety, click on the link below to download the U.S. Consumer Products Safety Commission’s bulletin entitled “Smoke Alarms - Why, Where, and Which?.”
Check Back of Smoke Alarm For Date
Not sure how old your smoke alarms are? Just unscrew them from the mounting and examine the back face. You will see the date of manufacture or a “replace before” date printed or stamped in small letters.
Also, see our blog posts Are smoke alarms required to sell a house? and Does pushing the test button on a smoke alarm test the smoke sensor device inside? and Where are smoke alarms required to be located?
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