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 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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Here’s links to a collection of our blog posts about SAFETY: 

Why is it important to use "cabinet screws" to mount the upper cabinets in the kitchen?

Is the door between an attached garage and the house required to have a closer (self-closing device)?

Can the smoke sensors in a home security/fire alarm system replace the smoke alarms required by the building code?

Should I get a lightning rod system to protect my house? 

What are the "Aging In Place" features to look for when buying a retirement home?

What is aging in place? 

How do I safely remove a dead rodent (rat, mouse or squirrel) from the attic?

What is the minimum height of a ceiling fan above the floor?

Should a smoke alarm be installed in the kitchen? 

Why is a double cylinder deadbolt lock on an exterior door a safety hazard? 

Why are rubber washing machine hoses a safety risk?

What can I do to avoid kitchen accidents and injuries? 

Are carbon monoxide alarms required to be installed in homes in Florida?

Are old vinyl tile floors dangerous?  

How can I use safety checks to limit my tenant liability for a rental house?

Do you inspect for trip hazards around the home? 

• Why is an anti-tip device now required behind the range? 

• What are the hazards to avoid when going into an attic? 

• What are the warning signs of a dangerous deck?
    Visit our SAFETY page for other related blog posts on this subject, or go to the INDEX for a complete listing of all our articles.

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