Find Out More About One of the Most Important Devices in
Your Home or Office
By Robert Reek
Home fires are a serious threat to your family’s safety.
Every year in the United States, approximately 5,000 people are killed in
residential fires and more than 40,000 are injured.
Most fire victims suffer from smoke and toxic gases, not
as a result of burns. Most deaths and injuries happen at night while the
victims are sleeping.
When properly installed and maintained, the home smoke
detector is considered one of the best, least expensive means of providing
early warning of a fire.
There is no doubt about it—smoke detectors save lives,
prevent injuries and minimize property damage by enabling residents to
detect fires early.
TYPES OF DETECTORS AND HOW THEY WORK
Ionization smoke detectors:
The ionization chamber smoke detector has a small
radiation source that produces radioactive material (electrically charged
particles called ions), which cause a small electrical current to flow
into a chamber. Smoke particles entering the chamber attach themselves to
the ions, reducing the electrical flow. The change in current sets off the
Photoelectric detectors use either an incandescent light
bulb or a light emitting diode (LED) to send a beam of light. When smoke
enters the detector, light from the beam is reflected from the smoke
particles into a photocell sensor and the alarm is triggered.
WHICH SMOKE DETECTOR IS BETTER?
The State Fire Marshal of California, as well as
nationally recognized testing agencies, approves both types of detectors.
Ionizing detectors respond slightly faster to flaming fires while
photoelectric detectors respond faster to smoldering fires. Ideally, a
home should be protected by at least one of each. If you can afford only
one type, a photoelectric detector is recommended.
LOCATION, LOCATION, LOCATION
Detectors should be installed either on the ceiling or on
walls between 6 and 12 inches below the ceiling.
Detectors should be located in each sleeping area, and
In multi-story homes, detectors should be located on each
story of the living area. Basement-level smoke detectors should be
installed in or near basement stairways in the basement, not at the top of
Do not place detectors closer than six inches of where
walls and ceilings meet or near heating and cooling ducts. A detector
placed in these areas may not get the required air flow to activate.
To avoid nuisance alarms place detectors:
•Away from furnace or air conditioner vents
•Away from bathrooms to avoid steam
•Away from a cooking area or fireplace
Battery operated smoke detectors should have the battery
replaced annually or when a low warning signal or chirping occurs.
It is important to use the exact make and model of battery
recommended by the detector’s manufacturer.
Accumulation of dust, dirt and insects can cause a false
alarm. Keep the detector clean by vacuuming around its exterior.
For more information on Environmental, Health and Safety
at SLAC, see: