Smoke Alarms & Detectors
Smoke detectors are devices that automatically sound a warning when they
sense smoke or other products of combustion. They are usually mounted on
a wall or the ceiling. When people are warned early enough about a fire,
they can escape before it spreads. You can purchase one starting at $6.
Every year house fires kill thousands. Fire kills an estimated 4,000
Americans every year. Another 30,000 people are seriously injured by
fire each year. Property damage from fire costs us at least $11.2
billion yearly. Most fire victims feel that fire would "never happen to
Although we like to feel safe at home, about two-thirds of our nation's
fire deaths happen in the victim's own home. The home is where we are at
the greatest risk and where we must take the most precautions. Most
deaths occur from inhaling smoke or poisonous gases, not from the
Most fatal fires occur in residential buildings between 11 p.m. and 6
a.m. when occupants are most likely asleep. Over 90 percent of fire
deaths in buildings occur in residential dwellings.
A Johns Hopkins University study, funded by the United States Fire
Administration, found that 75 percent of residential fire deaths and 84
percent of residential fire injuries could have been prevented by smoke
There are two basic types of smoke detectors:
Choosing a smoke detector
Ionization detectors - Ionization detectors contain
radioactive material that ionizes the air, making an electrical
path. When smoke enters, the smoke molecules attach themselves to
the ions. The change in electric current flow triggers the alarm.
The radioactive material is called americium. It's a radioactive
metallic element produced by bombardment of plutonium with high
energy neutrons. The amount is very small and not harmful.
Photo-electric detectors - This type of detector contains a
light source (usually a bulb) and a photocell, which is activated by
light. Light from the bulb reflects off the smoke particles and is
directed towards the photocell. The photocell then is activated to
trigger the alarm.
When choosing a smoke detector, there are several things to consider.
Think about which areas of the house you want to protect, where fire
would be most dangerous, how many you will need, etc.
The National Fire Protection Agency recommends that every home have a
smoke detector outside each sleeping area (inside as well if members of
the household sleep with the door closed) and on every level of the
home, including the basement. The National Fire Alarm code requires a
smoke detector inside each sleeping area for new construction. On floors
without bedrooms, detectors should be installed in or near living areas,
such as dens, living rooms or family rooms. Smoke detectors are not
recommended for kitchens.
The placement of smoke detectors is very important. Sleeping areas need
the most protection. One detector in a short hallway outside the bedroom
area is usually adequate. Hallways longer than 30 feet should have one
at each end. For maximum protection, install a detector in each bedroom.
Be sure to keep the detector away from fireplaces and wood stoves to
avoid false alarms. Place smoke detectors at the top of each stairwell
and at the end of each long hallway. Smoke rises easily through
stairwells. If you should put a smoke detector in your kitchen, be sure
to keep it away from cooking fumes or smoking areas.
It’s important to properly mount a smoke detector. You can mount many
detectors by yourself, however those connected to your household wiring
should have their own separate circuit and be installed by a
professional electrician. If you mount your detector on the ceiling, be
sure to keep it at least 18 inches away from dead air space near walls
and corners. If you mount it on the wall, place it six to 12 inches
below the ceiling and away from corners. Keep them high because smoke
Never place them any closer than three feet from an air register that
might re-circulate smoke. Don't place them near doorways or windows
where drafts could impair the detector operation. Don't place them on an
un-insulated exterior wall or ceiling. Temperature extremes can affect
It’s simple to keep smoke detectors in good condition. Always follow the
manufacturer's instructions. Be sure to replace the batteries every year
or as needed. Most models will make a chirping, popping or beeping sound
when the battery is losing its charge. When this sound is heard, install
a fresh battery, preferably an alkaline type.
Remember, every three years to change the bulbs. Keep extras handy.
Check the smoke detector every month by releasing smoke or pushing the
“test” button. Clean the detector face and grillwork often to remove
dust and grease. Never paint a smoke detector as it will hamper its
function. Check your detector if you've been away from home.
Smoke Detectors make great housewarming (or any time) gifts. It's an
interesting present that can save lives and it shows that you care.