Contains a small amount of radioactivity that conducts electricity. Electric current flows continuously between two electrodes in the chamber. When smoke particles enter, they disturb the flow, causing the alarm to go off. Photoelectric: Contains a beam of light and a photocell within the chamber. When smoke enters, it deflects the beam, causing it to strike the photocell and set off the alarm.
Ionization Versus Photoelectric:
Ionization alarms are more sensitive to the tiny particles of combustion that can't be seen or smelled, those emitted by flaming fires. Photoelectric alarms are more sensitive to the large particles of combustion emitted by smoldering fires. The differences between the two types are generally not critical, since the difference in response time is only a matter of seconds. Since most Home | Government | City Services | Community | Economic Development | Planning and Zoningfires produce a rich mixture of smoke types, with detectable amounts of both large-particle and small-particle smoke early in the fire's growth, either an ionization or a photoelectric alarm will meet most needs. Some of the newer alarms have a "hush" feature, which allows the alarm to be quieted in "nuisance" situations without removing the battery, and are recommended over the older alarms. Remember that a small investment - generally around $10 each - can save your life and the lives of your family. If you cannot afford a smoke alarm, contact the Hapeville Fire Department at (404) 766-4399.