Why Photoelectric Versus Ionization Smoke Alarms Make Sense

I think we can all agree smoke alarms are essential for home safety and have saved many lives through the years. According to the NFPA (National Fire Protection Association) 24% of the fire deaths occur in homes where the smoke alarms failed to operate.  Smoke alarms fail to operate when batteries are missing, are old and/or damaged, or have been disconnected due to nuisance alarms.  It has been reported that at least half of the deaths in 2011 occurred in homes where smoke alarms were not functioning because the battery was either missing or deliberately disabled because of nuisance alarms. For these reasons we often see campaigns to replace our smoke alarm batteries when we turn our clocks back. But this year it may be better to think about replacing the type of smoke alarms we are using versus just replacing the batteries.

When it comes to smoke alarms we have options. According to the National Fire Protection Association, the two most common technologies for fire alarms are Ionization and Photoelectric. Ionization smoke alarms are generally more responsive to flaming fires and Photoelectric smoke alarms are more responsive to fires that begin with a long period of smoldering (call “smoldering fires”).  Since you can’t predict what type of fire you may encounter, the NFPA currently recommends using a combination of both types of alarms throughout the house and/or by using alarms that incorporate both technologies

But here’s the catch. It is estimated that 90% of the alarms in use today are the ionization alarms because they’re less expensive than the photoelectric alarms. It should also be noted the ionization smoke alarms are known for more nuisance alarms due to cooking (that’s why people remove the batteries).  But an even bigger issue with ionization alarms; they are very slow to respond in a room filled with smoke due to a smoldering fire. Many residential fire fatalities occur at night and are result of smoke inhalation due to smoldering fires.

There is currently a move by many fire protection agencies to favor the Photoelectric smoke alarms for numerous reasons.  Photoelectric smoke alarms respond faster to smoldering fires than the ionization alarms. Also, the photoelectric smoke alarms tend to have less false (nuisance) alarms due to cooking.  Less nuisance alarms will hopefully result in more people not disconnecting their smoke alarms or removing the batteries.

Due to reports prepared for the Fire Protection Research Foundation by researchers with Underwriter Laboratories, The Consumer Products Safety Commission findings about nuisance alarms, and a Texas A&M University’s 3 year study of  Risk Analysis of Residential Fire Detector Performance; (ASHI), The American Society of Home Inspectors has recently passed a motion that ASHI will advocate  “the use of photoelectric smoke alarms in single and multi-family housing and discourage the use of ionization smoke alarms.

So; instead of just turning back the clocks this year, it maybe a good time to review the age, condition, and types of smoke alarms in your home and make an informed decision about how to better protect your family’s safety.