In recent years, authorities have shifted away from recommending ionisation smoke alarms in preference for photoelectric smoke alarms. Is one really better than the other? Are all types legal? We clarify the state of play and explain the differences between the two types of smoke alarms used in Australia.
Photoelectric Smoke Alarms
These alarms detect visible particles of combustion, which is why it’s often said that they “see” smoke. They work by aiming a light source into a sensing chamber so that when smoke particles enter the chamber, light is reflected onto the sensor and triggers the alarm.
Both in the real world and in controlled smoke alarm testing, photoelectric smoke alarms have been proven to respond significantly faster to smouldering fires. Smouldering fires are the most common type in the home environment; they’re slower burning and produce a lot of smoke, increasing the risk of smoke inhalation particularly if a fire starts when you’re asleep. The sooner you can be alerted to the fire, the more precious time you have to get yourself and your family to safety.
Photoelectric smoke alarms are also less likely to emit false alarms from cooking or from steam in the bathroom.
Ionisation Smoke Alarms
Ionisation smoke alarms detect invisible particles of combustion, which is why they’re often said to “smell” smoke. Ionisation smoke alarms contain a small amount of radioactive material between two electrically-charged plates. This material ionises the air, causing a current between the plates. When smoke enters the chamber the flow is disrupted and the alarm is activated.
While they are not generally recommended over photoelectric detectors, they do activate more quickly for fast-flaming fires. However, they are slower to respond to smouldering fires (the more common type of house fire), which can lead to visibility and breathing difficulties when occupants are attempting to escape a house fire.
Ionisation alarms are also prone to more false alarms, making people more likely to remove the battery and lose all protection.
How can I tell what’s in my home?
The label on each smoke detector should clearly state whether it is an ionisation or a photoelectric smoke alarm. Failing that, there will be a bright yellow “radiation” symbol inside or on the back of all ionisation alarms.
The Detector Inspector Service
In addition to choosing photoelectric smoke alarms, we know it’s important to install the right number of alarms in the right locations, and service smoke alarms regularly to keep occupants safe. Detector Inspector is committed to monitoring the latest research on smoke detectors and maintaining property safety to the highest standards in accordance with local legislation.
In NSW, Victoria and QLD we have already implemented solutions for our valued clients to meet updates to the RTA.
If you have any questions in relation to smoke alarms, home fire safety, or the solutions you need to stay ahead of upcoming legislation changes, please call us on 1300 134 563 today or submit an enquiry via below form.
