How Much Do You Know About Smoke Alarms?

October 9 through October 15 marks Fire Safety Week.

Did you know that there are two most commonly recognized smoke detection technologies – ionization smoke detection and photoelectric smoke detection.

Ionization Smoke Alarms

Ionization smoke alarms are generally more responsive to flaming fires.

How They Work

Ionization-type smoke alarms have a small amount of radioactive material between two electrically charged plates, which ionizes the air and causes current to flow between the plates. When smoke enters the chamber, it disrupts the flow of ions, thus reducing the flow of current and activating the alarm.

Photoelectric Smoke Alarms

Photoelectric smoke alarms are generally more responsive to fires that begin with a long period of smoldering (called “smoldering fires”).

How They Work:

Photoelectric-type alarms aim a light source into a sensing chamber at an angle away from the sensor. Smoke enters the chamber, reflecting light onto the light sensor; triggering the alarm.

Ultimately, it is no secret that smoke alarms should play an integral role in your fire strategy. 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 cannot 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.

For best protection, the National Fire Protection Association (NFPA) recommends that both ionization and photoelectric technologies be used in homes. In addition to individual ionization and photoelectric alarms, combination alarms that include both technologies in a single device are available. If you’re worried your smoke alarm isn’t working or want to learn more about your electrical contracting work then contact a reputable electrician for help and advice.
(Source and Images: NFPA)