Smoke Alarms Save Lives
The most important things you need to know are smoke alarms
save lives and they should be in every home. Follow these important
smoke alarm safety measures:
• Make sure your smoke alarms are working. This means testing
smoke alarms monthly, replacing batteries once a year
or when a low-battery alarm chirps and performing other
maintenance as NFPA and your smoke alarm manufacturers
recommend. And of course, a smoke alarm disabled because
of nuisance alarms provides no protection at all.
• It is important to have not just one smoke alarm but smoke
alarms in every location required by NFPA standards. (On
each level of your home, outside each sleeping area and
inside each bedroom.) Tens of millions of U.S. homes are estimated
to have smoke alarms but not enough smoke alarms
to meet the standards and protect their homes.
• Interconnect your smoke alarms so that a fire detected
by any smoke alarm will sound an alarm at every location
where a smoke alarm is installed. Interconnection can be
done using hard-wiring or wireless broadcast technology.
Interconnected smoke alarms provide early warning of fires
that are still far away or are located on the other side of a
door or wall that may block sound.
• Develop and practice an escape plan so that everyone in
the home knows what to do if the smoke alarm sounds.
That includes planning a second way out from every room in
your home. Every household that develops and practices an
escape plan with two ways out from every location improves
its time to escape in every type of fire.
There Are Different Types of Smoke Alarm
Technologies—Ionization and Photoelectric
The two most commonly recognized smoke detection technologies
are ionization smoke detection and photoelectric smoke detection.
Ionization smoke detection is generally more responsive to flaming
fires and photoelectric smoke detection is generally more responsive
to fires that begin with a long period of smoldering (called
“smoldering fires”). For each type of smoke alarm, the advantage it
provides may be critical to life safety in some fire situations.
Home fatal fires, day or night, include a large number of
smoldering fires and a large number of flaming fires. You can
not predict the type of fire you may have in your home or when it
will occur. Any smoke alarm technology, to be acceptable, must
perform acceptably for both types of fires in order to provide early
warning of fire at all times of the day or night and whether you are
asleep or awake.
The best evidence has always indicated that either type of
smoke alarm will provide sufficient time for escape for most
people for most fires of either smoldering or flaming type. However,
research is ongoing, and standards are living documents. If
at any time, research points to a different conclusion, then that
will lead to proposals for changes in the NFPA standard or the
closely related Underwriters Laboratories standard for testing
and approving smoke alarms. Both organizations currently have
task groups looking at smoke alarm performance in the current
home environment.
For Best Protection Use Both Types of
Smoke Alarm Technologies
For best protection, it is recommended both (ionization and
photoelectric) technologies be in homes. In addition to individual
ionization and photoelectric alarms, combination alarms
that include both technologies in a single device are available.
Nuisance Alarms Can Be Minimized
Ionization type smoke alarms are more susceptible to nuisance
alarms due to cooking, the leading cause of nuisance alarms,
but both types have some susceptibility to nuisance alarms from
cooking fumes, and both have susceptibility to nuisance alarms
from the steam from a hot shower.
In the past decade or so, a number of steps have been taken
to reduce the likelihood of nuisance alarms, including hush features
and refinements to installation rules that include guidance
on safe distances from nuisance sources.
TV Demonstrations of Smoke Alarm Performance
Can Be Misleading
Informal demonstrations, such as ones done for TV news shows,
of smoke alarm performance can seriously mislead the viewer
and do not provide a sound basis to assess performance. These
demonstration tests are not performed in a controlled or scientific
way that compares the time of smoke alarm operation to
the time when occupants would be incapacitated. The selected
fire scenarios may not be representative of real fatal home fires.
Passing or failing a “test” of this sort may have nothing to do
with performing well or badly in the wide range of real fires. A
valid engineering analysis must select fires that are realistic and
analyze them accordingly.
In an informal demonstration, the eye reacts to conditions
that look dangerous, mostly visible smoke and visible flame.
However, most people are killed by invisible gases, which do not
necessarily spread at the same rate as smoke or flame. A valid
engineering analysis must measure conditions caused by fires
and assess them according to their real danger.