Types of Smoke Detectors: Knowing the Difference
You change the batteries in your smoke detectors twice a year, and test them every month. But do you know what type of smoke detectors you have? Or, that having one kind over another may make a difference?
There are two main smoke detector types, and each has a sensor that detects smoke and fire differently, depending on the origin of the fire.
What Is an Ionization Smoke Detector?
The first smoke detector type, ionization alarms are generally more responsive to a flaming fire (for instance, when a lit candle tips over and ignites a curtain), according to the National Fire Protection Association (NFPA). These alarms use “ions,” or electrically charged particles, to help detect smoke in the air.
What Is a Photoelectric Smoke Detector?
The second type of smoke detector is photoelectric, which uses a light beam to help detect the presence of smoke. According to NFPA, 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 may 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 help 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 NFPA 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 from the North Eastern Ohio Fire Prevention Association: Take the smoke alarm down and look at the back for either the word “Photoelectric” or “Ionization.” You might also see a symbol with the letter “P” or “I” on the back.)
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.
Make Sure Smoke Detectors Are Working Properly
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 NFPA, an estimated 24 percent of smoke alarms failures were caused by dead batteries between 2009 to 2013.
So, start by making sure you have the right number of smoke alarms in the right places and each alarm has fresh batteries. 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).
With a little preparation, your smoke alarms can be ready to alert you of a home fire.
Originally published on April 3, 2013.