Smoke House Fire

Not All Smoke Alarms are Equal: Knowing the Difference Could Save Your Life

You change the batteries in your smoke alarms twice a year, and test them every month. But do you know what type of smoke alarms you have? Or, that having one kind over another can make a difference in getting out safely in a home fire?

There are two chief smoke alarm types, and each has a sensor that detects smoke and fire differently depending on the origin of the fire.

Ionization vs. photoelectric smoke alarms

The most common smoke alarm type, Ionization alarms are generally more responsive to a flaming fire (for instance, when a lit candle tips over and ignites a towel), according to Underwriters Laboratories. These alarms use “ions,” or electrically charged particles, to detect smoke in the air. UL says that, because they are inexpensive, ionization detectors are the most commonly found smoke alarms in North American homes.

The second type of detector is the photoelectric smoke alarm, which uses a light beam to detect the presence of smoke. According to UL, these alarm types are more effective at sounding when a fire originates from a smoldering source, like a lit cigarette that falls into a couch cushion. Smoldering fires can fill a home with dangerous gases before a fire ever erupts.

Which smoke alarm type is best?

So, which alarm to choose? While both types of smoke detectors are designed to detect any house fire, no matter the source, each technology has its advantages and can offer an earlier warning over the other, depending on the origin of a fire.

The challenge is that it’s impossible to predict which type of fire could erupt in your home, which is why the National Fire Protection Association says the best protection is offered by having both alarm technologies in your home.

There are a couple of ways to get this done.

If your existing detectors are ionization smoke alarms, you can purchase photoelectric smoke alarms and install one next to each ionization unit. If you don’t know what type you have, check your owner’s manual. (Or, try this tip: Take the smoke alarm down and look at the back. Because ionization alarms all contain a trace amount of a radioactive material, Americium 241, they contain a warning about the material on each alarm. If you see this warning on your device, you have an ionization unit.)

Another option: If budget allows, consider replacing all of your existing smoke alarms with dual-sensor devices, which combine both ionization and photoelectric technologies in a single unit.

Maintenance is key, regardless of type

Knowing the type of smoke alarm you have is clearly an important part of fire safety, but experts also warn that, regardless of type, smoke alarms won’t protect you if they’re not working properly.

According to UL, an estimated 20 percent of homes have detectors that do not work or are missing batteries, and two-thirds of reported residential fire deaths occur in homes without working smoke alarms, or with no smoke alarms at all.

So, start by making sure you have the right number of smoke alarms in the right places. The NFPA recommends a smoke detector in every bedroom, outside each separate sleeping area and on every level of your home (smoke rises, so install them high on the walls).

Then, set reminders to swap out the batteries on each unit at least once a year, and to test the units monthly.

Are your smoke alarms ready to alert you to a home fire? 

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