Does Your Smoke Detector Really Work?

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There has been a reduction in fire deaths and injuries resulting from the widespread use of smoke detectors.  Despite the widespread presence of detectors, there are still thousands each year who die or suffer painful, disfiguring injuries as a result of fires in their homes.  The United States has been identified as a world leader in many respects. Unfortunately, we also lead the industrialized world in home fire casualties.  It has been estimated that smoke detectors reduce the risk of dying in a house fire by at least 50%-but only if the smoke detector is working.

Sixteen million smoke detectors in U.S. homes don't work - so says the U.S. Government, based on a recent 1994-95 survey conducted as part of the "National Smoke Detector Project."  This means that more than one of every four homes equipped with smoke detectors is literally at risk in the event of a fire.   In fact, the government report shows that there are more homes that have smoke detectors that don't work than there are homes that don't have detectors at all.

Why are there so many defective smoke detectors? According to the government investigators, it is because:

  • Batteries were found to be dead or missing.

  • The detector's vents were clogged with dirt, dust, or grease.

  • The sensing chamber was infested by insects.


More important than the reasons identified for this serious problem is what can be done about it.  The solution is simple enough: Test the detector regularly.  Every smoke detector's user manual emphasizes the need for doing so.  The National Fire Protection Association recommends that battery-powered detectors be tested weekly, and that those powered by household current be tested monthly.  Indeed, the Association each year promotes "National Fire Prevention Week," during the first week of October.  Typical is the Association's theme for 1996: "Let's Hear it for Fire Safety - Test Your Detectors!"
But why isn't testing being done?  Why aren't homeowners following these important recommendations?  After all, the claim is made, simply press the test button on the detector.  If the alarm sounds, then, it is claimed,  you can be sure that your detector will give you and your family the early warning you need in order to exit safely and avoid a tragedy.
To gain a better understanding of this serious problem, it is necessary to examine the assumptions underlying the "test button test."  The correct location for the smoke detector, according to fire experts, is on the ceiling in the center of the room. But the ceiling height in most homes is eight feet from the floor.  This means that unless the homeowner is a professional basketball player, he or she must stand on a chair or on some other elevation. Here are some practical considerations: How many homeowners are going to make the effort every week to drag a chair or stool over to the smoke detector?  What about the elderly or the infirm?  What about those who are wheelchair bound?  What about the millions of smoke detectors without test buttons?
In view of these considerations, some have asked, why not use a broomstick to press the test button?  The answer: Repeated jabbing of the test button with this clumsy object will soon force displacement of the test button from its contacts or otherwise damage it.  Indeed, in its 1994 report on smoke detector operability, the Government report found detectors with damaged components suggesting that, at least in some instances, homeowners were following these ill-advised suggestions.  Then, too, the test button recess in many types of smoke detectors has a diameter smaller than that of a broomstick, effectively preventing the button from being depressed by this means. Finally, it is literally impossible to use a broomstick to press the button on wall mounted units.
What of the test button itself?  Does it signal a valid test?   The alarm goes off when you press the test button. Okay.  Does that mean it will always give the alarm in the event of a fire?  That it will respond to the presence of smoke?  The government investigators found, on the contrary, that the "test button test" does not always signify that the detector will sound in the event of a fire.  A number of smoke detectors were found to have their vents clogged with dust, dirt or grease; in other instances, insects had infested the sensing chamber.   In all such cases, smoke did not activate the alarm but the test button nevertheless caused the alarm to sound.
What, then, is the best way of testing smoke detectors?  The simplest, easiest way of doing so is by using an aerosol product that has been tested and approved by a recognized testing facility like Underwriters Labs. Home Safeguard Industries makes such a product. Indeed, it was the first of its kind and has become the world standard for the testing of smoke detectors of all kinds.  Smoke Detector Tester was used in the government survey referred to in this article because it was found to be reliable, effective and easy to use. 
The government investigators followed the simple instructions on the can's label: "Spray the smoke detector for one to two seconds from a distance of two to four feet."  That's how they found that 16 million smoke detectors in U.S. homes don't work.

If you, too, follow these simple instructions, you will quickly learn whether your smoke detector will warn you in the event of the "real thing." If , following the spraying, your smoke detector goes into alarm, you can be sure that it will do its job in the event of a fire in your home. If the alarm does not go off, chances are you have a defective detector.

Here's what to do if the alarm doesn't sound:

A smoke detector has probably been damaged and will not operate if it has been painted over.  Also, an older detector - say, 10 years old - is likely to have corroded contacts or otherwise faulty electronics, causing the alarm to go off too late, too soon, or not at all.  Under any of these circumstances, the detector is not doing the job it was designed to do.  It should be replaced.  After all, according to one estimate, a smoke detector that has been in operation for 10 years has gone through more than 3.5 million monitoring cycles.  And detectors these days are not that expensive, especially considering your family's safety.

In the event of replacement, what kind of detector should you have in your home?

There are two kinds of detectors on the market today, ionization and photoelectric.  Ionization detectors have a quantity of radioactive material in the sensing chamber which throws off a constant stream of radioactive particles.  This action creates an electric charge in the chamber.  When smoke enters the chamber, it reduces the electric charge.  When the electric charge falls below a preset amount, the alarm, is initiated.  Photoelectric smoke detectors, on the other hand, have a beam of light inside of their sensing chamber.   When the beam is broken up or deflected the alarm is sounded.

Of the two types of smoke detectors, the ionization type is by far the most common.   More than three of every four detectors in U.S. homes today are ionization detectors, according to the government report.  The reason is simple: They are much less expensive than photoelectric detectors.  But ionization detectors have a serious downside: they are prone to nuisance, or false, alarms. Indeed, the ionization technology itself is the problem. Ionization devices are designed to detect advance particles of combustion, causing the detector to respond to the most minute airborne particles. Routine kitchen activities, including cooking and dish washing, can cause the alarm to sound, as can spraying windows with conventional window cleaners.  An ionization detector near a bathroom may sound the alarm when you are showering or bathing.

The super-sensitivity of ionization detectors is why many detectors in the government study were found to have missing batteries.  Homeowners simply removed the batteries, thus sparing themselves the constant annoyance of the alarm's sounding during daily activities.

To add to the ionization problem, these detectors contain a radioactive substance, Americium 241, a by product of the production of plutonium.  To be sure, the radioactive substance involved is small, but there are tens of millions of this kind of detector in U.S. homes now, with more being added daily.  This simply aggravates problems related to the disposal of radioactive materials, which we in the U.S. and, indeed, the world, face on a daily basis.

To adequately protect your family and home you should take the following steps:

Here's what smoke detector manufacturers should do: 

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