Smoke Detector Information



Why do I need smoke detectors?


By installing and maintaining smoke detectors, it is estimated that you can reduce your chance of dying from a fire by 50%. How? Smoke detectors detect the presence of a fire long before someone senses heat from a fire. It is most always smoke that is the cause of death compared to heat. People will breathe in smoke and heated gases long before they are exposed to heat.


How do smoke detectors work?


Smoke detectors operate on two different principles. The first is called photoelectric which uses a beam of light. One part of the detector shines a beam of light and another can “see” the beam. When smoke enters the chamber, it scatters the light and blocks the detector from seeing the light. When this happens, the detector sees this and sounds the buzzer. The second kind is called an ionization detector. It uses a small piece of radioactive material to charge the air. The air flows to two electrodes passing along electricity. When smoke enters the chamber, it interferes with the flow of electricity and sounds the buzzer. Most of the detectors you can purchase at the store are of the ionization type.


Where do I install my smoke detector?


The National Fire Protection Association (NFPA) establishes the standard of installing smoke detectors. NFPA standard 72 requires as a minimum that:


  • One smoke detector is installed on every level of a house.
  • One smoke detector is installed outside every sleeping room.
  • Every sleeping room has a smoke detector installed in it.

Smoke detectors can be installed on both the ceiling and the wall. When installing a smoke detector on the wall, you should place it no closer than four inches to the ceiling and no farther than twelve inches below the ceiling. If you install a smoke detector on the ceiling, you should install it near the center of the room.


When should I replace my battery?


It is a good practice to change the battery in your smoke detector when we change the time in the spring and fall. Battery operated smoke detectors do have a built-in alert feature to let you know it is time for a new battery. Smoke detectors will begin to beep every few seconds when the battery is low. You should not remove the battery from the smoke detector until you have a replacement battery.


Do I ever need to replace my detector?


NFPA recommends that you replace smoke detectors after ten years of use.