Photoelectric smoke alarms are smoke alarms that use a light-emitting diode and a light-sensitive sensor to detect smoke particles suspended in the air. These smoke particles scatter the light beam which in turn sets off the sensor causing the alarm to sound.
Photoelectric smoke detectors are more effective at detecting smoky or smouldering fires, which is the most common way fires in the home present. Their ability to detect fires in the early stages before flames have well and truly taken hold makes them a much better choice. Early detection significantly improves the chances of occupants making it to safety.
While photoelectric smoke alarms excel at detecting fires in the early stages while they smoulder and smoke ionisation smoke alarms are activated by the presence of flames. Both types of alarms offer a measure of protection, however, for improved chances of escaping a fire before it is too late, photoelectric smoke alarms are the preferred option for your home.
Be sure to review your state’s legislation regarding approved smoke alarms for your home. In Queensland, only photoelectric, interconnected alarms are permitted as of January 1, 2022.
It is not so much a question of which type of smoke alarm is better, than which is more effective. As photoelectric smoke alarms sound in the early stages of fire when smoke is detected, they provide much needed time to escape.
Relying on ionisation smoke alarms means you may not be aware there is a fire in your property until the flames have already taken hold and are blocking your exits. Both types of alarms alert you to fire, but only photoelectric can give you the headstart you need to make it to safety. This is why some states such as Queensland have now legislated that only photoelectric smoke alarms may be used.
Ionisation smoke alarms contain a small amount of radioactive material in the form of americium-24. These isotopes emit alpha particles when flames are detected that causes the ionisation in the air and the alarm to trigger.
So are photoelectric smoke detectors also radioactive? No, there is no radioactive material used in the making of photoelectric smoke detector, making them safe for use in your home. They rely only on a light-emitting diode and light sensor.
The ideal locations to install a photoelectric smoke detector include every room where someone sleeps. Place them in the immediate area of bedrooms and the path of exit from each room.
Queensland legislation requires all smoke alarms to be interconnected, so when one sounds, they all sound. This ensures a sleep hears the alarm even if they sleep with the door closed – it is recommended to interconnect your alarms no matter what your state legislation advises for this exact reason. Should any hallway or room in the home exceed 9.1 meters in length, photoelectric smoke detectors should be placed at both ends.
They should also be placed in stairways, stairways act like chimneys for smoke and heat which can rapidly cause a fire to spread. In addition to this, photoelectric smoke detectors should also be placed in any room where large electrical appliances are in use, such as portable heaters or humidifiers.
