An ionization smoke alarm is one of the two types of smoke detectors used in homes and businesses everywhere. Both an ionization smoke alarm and the other type, a photoelectric smoke alarm are effective at detecting the early warning signs of fire, but they use different methods to do so. Photoelectric smoke alarms are designed to detect the visible effects of fire, namely, plumes of thick smoke. Ionization smoke alarms, on the other hand, are more sensitive detectors and are able to notice fire particles that are less visible.
How an Ionization Smoke Alarm Works
An ionization smoke alarm utilizes a source of ionizing radiation to more accurately detect smoke. Inside this type of smoke alarm is an ionizing chamber. It is comprised of two metal plates, a battery and a small source of radiation, americium-241. The minutely radioactive particle ionizes the oxygen and nitrogen in the air that circulates through the smoke alarm, thereby creating a small current flowing through the metal plates. When smoke enters the chamber, this current is disrupted and the alarm sounds.
Which Type to Use
Photoelectric smoke alarms are less sensitive, for they essentially emit a beam of light that, when blocked, triggers the alarm. Both ionization and photoelectric smoke alarms are useful, though. Together they offer a suitable means of fire safety.