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Types of Smoke Alarms


Types of smoke alarms

Ionisation and photoelectric smoke alarms

There are two main types of smoke alarms for home use: ionisation and photoelectric.

Photoelectric smoke alarms are usually much faster at detecting smoke from smouldering synthetic material than ionisation alarms.

In a typical house fire burning material smoulders and smokes for a long time (possibly a few hours) before flaring into flames. It's vital to detect the fire early in the smouldering phase so you can put out the fire or escape.

Studies have shown that photoelectric alarms typically respond to smoky fires within about three to five minutes. Ionisation alarms can take much longer – up to 20 minutes or more – by which time escape can be much more difficult.

We recommend you install photoelectric smoke alarms in your home.

Mains powered or battery operated smoke alarms

Smoke alarms connected to 240 volt mains power (known as mains powered smoke alarms) are required in residential homes:

  • Newly built since 1997
  • Having undergone significant renovations since 1997
  • Sold since October 2009
  • Made available for rent or hire.

  • In all other homes we recommend the installation of mains powered smoke alarms as they are more reliable.

    If mains powered smoke alarms are outside your budget, the next best option is long life lithium powered (10 year) smoke alarms. These smoke alarms will give you up to 10 years of smoke detection without needing to replace the batteries. The benefits are huge:

  • They remove the frustration of fixing the flat battery ‘beep’
  • You’re not having to pay for replaceable batteries each year (something to consider when comparing prices)
  • You don’t have to climb ladders to replace batteries every year.

  • Otherwise install battery operated smoke alarms that have a user-replaceable battery. You will need to change the battery at least once-a-year using a 9-volt battery.

    All mains powered smoke alarms must be installed by a qualified electrical contractor.

    What to look for when purchasing a smoke alarm

    Standards Australia Certification

    Smoke alarms in Australia are required to comply with the Australian Standard, AS3786. In Western Australia, newly installed smoke alarms must comply with the current version of the standard AS3786:2014 (which is clearly marked on the smoke alarm).

    10 year battery

    Some models come with a pre-installed non-removable 10-year battery, typically a lithium battery, which will last for the life of the smoke alarm. This means you don't need to remember to change the battery each year.

    Remember, even mains powered alarms have back-up batteries, so check they have a non-removable (or rechargeable) battery.

    Test button

    This allows you to check the alarm is working. Some models can be tested by shining a torch on the alarm, or by using a household remote control (such as a TV remote). This eliminates the need to climb a ladder or reach up with a broom handle to press a button – especially good for high ceilings or if you're not very mobile.

    Hush button

    Pressing this button silences nuisance alarms for a few minutes – handy if you've burnt the toast and set off the alarm, as it gives you some quiet while the smoke dissipates. Some alarms can even be silenced by remote control.

    Expiry date

    A visible expiry date is handy as all smoke alarms have a maximum 10 year service life. After that time smoke alarms may fail to alert you when there is a fire, as their efficiency is compromised by the accumulation of dust, insects and corrosion of electrical circuitry.

    WA legislation requires mains powered smoke alarms to be installed in houses that are rented, hired or sold. These smoke alarms must also be replaced every 10 years.


    Most mains-powered and some battery-powered alarms can be connected to each other so that if one goes off so do the rest. This means all occupants will be alerted to a fire in your home at the same time. If your home was built after the 1 May 2015, you are required by law to interconnect your smoke alarms.

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