SMOKE DETECTORS
Its pure and simple, Smoke
Detectors Save Lives.
This page will form a basis of what the smoke detector does and how you should
use it.
Photoelectric versus Ionization Detectors
Ionization detectors use a small
amount of radioactive material to make the air within a sensing chamber conduct
electricity. Smoke particles even smaller than the eye can see will enter
the detector chamber and trigger the alarm. The greatest number of these small
particles are produced by flaming fire resulting in the ionization detector
to respond faster to open flaming fires than photoelectric detectors.
Photoelectric detectors use
a small light source which shines its light into a dark chamber not normally
exposed to light. This dark chamber contains a photocell to detect light.
When smoke particles enter the sensing chamber, light is reflected off of
them and into the sensing chamber. This causes the alarm to trigger. This
method needs bigger smoke particles than ionization detectors which is usually
formed from smoldering fires.
Now which should I use? Even though the average particle size changes considerably with temperature, fires usually produce a broad range of particle sizes. Therefore, both types of detectors will detect most fires.
Installing Smoke Detectors
Since smoke rises, smoke detectors should be installed on ceilings. Avoid
placing detectors high in corners where the wall and ceiling meet. Also, avoid
installing detectors within three feet of an air supply register or return.
Smoke could be pushed or pulled away from the detector by air flow.
Escape Plan
This provides a brief overview of smoke detectors. However a smoke detector
cannot put out a fire or get people out of a fire. All family members should
know two exits from their home and preplan where you should meet once evacuated.
Escape planning must be part of your smoke detector protection. The alternative
is a false sense of security which can lead to tragedy.
For further information contact Framingham Fire Prevention at 508-620-4943
