A flaming fire devours combustibles quickly, spreads rapidly and generates considerable heat with little smoke. Ionization smoke alarms respond first to fast flaming fires and are generally less expensive and more common than photoelectric smoke alarms.

This type of alarm uses a small amount of radioactive material to ionize air in the sensing chamber. As a result, the air chamber becomes conductive permitting current to flow between two charged electrodes. When smoke particles enter the chamber, the conductivity of the chamber air decreases. When this reduction in conductivity is reduced to a predetermined level, the alarm is set off. Most smoke alarms in use are of this type.

A smoldering fire generates large amounts of thick, black smoke with little heat and may smolder for hours before bursting into flames. Photoelectric smoke alarms respond first to slow smouldering fires and are less prone to nuisance alarms in the kitchen area.

A photoelectric type smoke alarm consists of a light emitting diode and a light sensitive sensor in the sensing chamber. The presence of suspended smoke particles in the chamber scatters the light beam. This scattered light is detected and sets off the alarm.

Ideally, both types of smoke alarms should be installed in your home, however as both types of alarms have proven to save lives either type is very effective as an early warning device.

Should you wish to install a photoelectric smoke alarm in your home, then we would suggest you do so near the kitchen, in the living room, or in the bedrooms. We recommend that you do not install an Ionization type smoke alarm near a kitchen or bathroom, but these alarms can be placed in all other areas or your home.

Should you have any further questions, please do not hesitate to call the Fire Prevention Bureau at 519.752.0540.