Photoelectric vs Ionisation – What’s the difference?

A photoelectric smoke alarm’s sensing chamber contains a light emitting diode and a light sensitive receiver. When smoke, or other by-products of combustion, fills this chamber the light beam is scattered and sets off the alarm.

Photoelectric smoke alarms are suitable for living rooms, dining rooms, hallways and bedrooms. This is because these rooms often contain large pieces of furniture such as sofas, chairs, and mattresses, which, while burning, will create more smouldering smoke than intense flame and heat. However photoelectric smoke alarms will recognise both fire stages. This type of smoke alarm is now the internationally recommended solution for household use.

An ionisation type smoke alarm uses 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, or other by-products of combustion enter the chamber, the conductivity of the air within the chamber decreases. When this reduction in conductivity is reduced to a predetermined level, the alarm is set off.

For the past decade, it has been recognised around the world – from conducting laboratory and field testing – that Photoelectric alarms respond significantly faster to smouldering fires which are more common.

The Cavius Photoelectric smoke alarm
The Danish-designed Cavius Photoelectric Smoke Alarm is a welcome change to the traditionally large and unsightly smoke alarms we have had for years. Using all the recommended technologies from the global fire services, it offers early detection of a home fire with a loud piercing audio alert when smoke is detected, and it just looks great! Being so small and aesthetically pleasing you don’t mind placing it where it will work best – right in the centre of the room.

Don’t forget about our Thermal Heat Alarm – designed to detect fast, flaming fires in the areas not suitable to install smoke alarms such as kitchens, garages, workshops, or laundries.

The Cavius 40mm alarms come fitted with a 10-year long-life battery. Once they are installed with the unique and simple “Smart Clip” ceiling mechanism, the battery is activated. They have an audio alert output of 85dB(A) at 3 metres, generating a piercing alarm designed to wake you from your sleep.

Cavius devices have a 30-day low battery warning, increasing your chances of identifying that your smoke alarms need to be replaced.