Smoke Alarms - Different Types

Not all fires are the same! And not all ‘smoke detectors' are the same!
 

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

This type of detector 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 detector is set off. Most smoke detectors 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 detectors respond first to slow smoldering fires and are less prone to nuisance alarms in the kitchen area.

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

Should you wish to install a photoelectric smoke detector 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 detectors near a kitchen or bathroom, but these detectors can be placed in all other areas or your home.