Smoke Detectors - Deadly Differences

  Smoke Detectors That Can Kill 

Like most, I always believed that a smoke alarm was a smoke alarm. After all, every smoke alarm sold must be tested and approved.  The reality is that all smoke alarms are not the same.  Most residential smoke alarms are either ionization or photoelectric type alarms.  Around 95% of the smoke alarms installed in US homes are ionization type alarms.  There are very significant differences in how these 2 types of alarms respond in real-world fires.  Ionization alarms are notorious for nuisance tripping, such as from cooking, steam from a shower, etc.  But ionization alarms are very slow to respond in the smoldering fires that account for most residential fire deaths.

“I estimate that at least 10,000-15,000 people have died unnecessarily in smoldering house fires since 1990 because they relied on Ionization detectors”,  Jay Fleming, Boston Deputy Fire Chief.

Ionization alarms respond marginally faster in an open-flame fire than photoelectric smoke alarms.  However, most residential fire fatalities are due to smoke inhalation and occur at night. In a smoldering fire, ionization alarms respond an average 30 to 90 minutes slower than photoelectric alarms.  Over half time, an ionization alarm will fail to notify occupants quickly enough to allow them escape a fire and many will fail to respond at all.  

In older tests, the point at which a fire goes critical occurred in as little as 12-14 minutes.  Due largely to the increased use of synthetic and engineered materials, this can now occur in as little as 2-4 minutes.  This leaves our families and friends with significantly less time to safely exit the home when a fire occurs.

The problem with ionization alarms isn't just the slow response times.  People become frustrated because ionization alarms nuisance trip when cooking, etc.  They often intentionally remove or disable the alarm, leaving their home completely unprotected. Around 2/3's of all fire deaths occur in unprotected homes.  Ionization alarms are found in over 80% of the homes where alarms were disabled.  Many of the other 1/3 of fire deaths occur in homes where an alarm sounds, but it sounds too late to allow the occupants escape.

There is significant private, university and government data going back to the mid-1970's showing that ionization alarms fail to protect occupants in smoldering fires.  Despite installing hundreds of millions of smoke alarms the last 30 years in US homes, the death rate in residential fires has remained essentially unchanged. Boston Deputy Fire Chief has been campaigning to ban ionization units since the early 1990's.  Although it has taken decades, there is finally a growing public awareness of this issue. Recently, the International Association of Firefighters (IAFF) took a stand and now recommends that only photoelectric smoke alarms be installed.  Both Vermont and Massachusetts now require photoelectric smoke alarms in residential construction. In July, 2010, the City of Albany, California became the first city in California to require photoelectric smoke alarms in new construction and remodels.  In 2010, the cities of Palo Alto and Orange also enacted ordinances requiring photoelectric technology alarms.  In January 2011, the City of Sebastopol enacted an ordinance requiring photoelectric technology. Hopefully, California will step up and join Vermont and Massachusetts in requiring photoelectric technology alarms at the state level.

Albany, CA has required “the immediate removal of the fraudulent, deadly, ionization so-called smoke alarms from all stores and homes before more people are needlessly maimed or killed.”

Which Ones Do I Have?

It is not always possible to know.  In general, if the unit has a “Hush” feature, it is an ionization unit.  If the label says anything about radioactive materials, Americium-241 or the model number ends in an “I” - then it is an ionization unit.  When there is any doubt, there is a 95% chance it is an ionization unit.  To be safe, simply replace any unknown units with photoelectric alarms.

There are combination photoelectric/ionization units on the market.  These suffer the same issues as ionization only detectors and in some cases – they may actually be worse.  They will nuisance trip due to the ionization

The manufacturers also appear to have reduced the overall sensitivity/response of these combination units to smoke in order to cut nuisance tripping. There are other design issues with certain combination alarms that make them less effective than photoelectric only alarms. The International Association of Firefighters specifically recommends not installing combination alarms.

There are also combination photoelectric/carbon monoxide (CO) alarms.  These combination units are more expensive.  For safety reasons, smoke alarms should be replaced every 10 years.  Most carbon monoxide detectors should be replaced every 5 years.  With combination units, you are either replacing the smoke portion away before it needs to be or relying on a CO detector may be beyond its replacement date.  Separate units simply make more sense.

In much of California, either type of alarm will meet the “legal” requirement on-sale.  However, if your client needs to install smoke alarms to meet the on-sale requirements – please encourage them to install photoelectric alarms.  Photoelectric alarms only cost a few dollars more and provide the best protection available today.

Carbon monoxide detectors should be considered with the same importance as the smoke detectors.  They too prove fatal in thousands of instances each year.  In one sense they are even more important.  There are several warning signs with a fire but carbon monoxide gives no warning signs at all.

It is critical that public awareness of this issue become the top priority for each of us. This personally impacts the safety of nearly every one of us.  This year, don't just replace your smoke alarm batteries – replace your alarms with photoelectric alarms and recommend that our families, friends, neighbors and clients do the same!