Queensland legislation means that residential property owners have to replace ionization smoke detectors with photoelectric smoke alarms. But why this change in residential fire protection legislation? It is all to do with how photoelectric smoke detectors work.
What are the different types of smoke detectors?
Before, we used to rely on heat detectors. However, these devices rely on the air reaching a certain temperature, or detecting a sudden increase in temperature, to trigger the alarm. This is not an adequate measure for homes, and so we use smoke detectors instead.
Most smoke alarms falls into one of two categories: ionization smoke alarms or photoelectric smoke detectors. There are also some smoke alarms that are a combination of these two types of smoke alarm.
The different types of smoke detectors work in different ways. Ionization smoke alarms detect flaming fires. Photoelectric smoke alarms, on the other hand, detect smoke particles in the air. Therefore, each works better at detecting a different type of fire.
This is how ionization smoke alarms detect flames…
An ionization smoke alarm consists of two electrically charged plates, with a small amount of radioactive material between them. This radioactive material ionizes the air, creating negative and positive air molecules in what is known as the ionization chamber. The ionization creates a current (in other words, electricity) that flows between the two plates.
In the case of a fire, smoke enters the ionization chamber and absorbs the alpha particles. This interferes with the ionization process and decreases the current. It is the reduction in electricity being passed between the two plates that triggers the alarm.
And this is how photoelectric smoke detectors work…
Photoelectric smoke alarms are better at detecting smoldering fires. These smoke alarms work with a light source and a photoelectric sensor. The light source emits a beam of LED light straight across the inner chamber of the smoke alarm. The light sensor is placed at the base of the smoke detector, out of the path of the LED beam.
When smoke enters the chamber of a photoelectric smoke alarm, it scatters the LED light in all different directions. When some of the LED light hits the photoelectric sensor, it triggers the fire alarm.
A house fire can smoulder for a long time before it burns flames. Thus, a photoelectric smoke alarm would give an earlier warning compared to an ionization smoke alarm. Based on how photoelectric smoke detectors work, they will soon be required in all Queensland residential properties.
Is property complaint with the latest smoke alarm legislation in Queensland?
There is new smoke alarm legislation coming into effect in Queensland on 1 January 2022. All properties that are sold or leased from January 2022 onwards have to be compliant. What does this mean?
You are required to install interconnected photoelectric smoke alarms before you can lease or sell a residential property in Queensland. The requirements are as follows:
- You must install photoelectric smoke alarms without an ionization chamber.
- You must ensure that all smoke alarms meet Australian Standard 3786-2014.
- The manufacturer must have clearly marked each smoke alarm as being compliant.
- You must install a smoke alarm outside each bedroom, and in each hallway connecting the bedrooms to the rest of the storey.
- If there is no hallway, you must install a smoke alarm where the bedrooms connect to the rest of the storey.
- In the case of a storey that doesn’t have a bedroom, you must install at least one smoke alarm on that level. You must place the smoke alarm along the most likely path of travel to exit the home.
- You need to make sure that all smoke alarms are interconnected on one network.
- In terms of power supply, you can opt for a hardwired system or a wireless network.