It's a situation no one wants to have to face, but firefighters fight thousands of building fires every year and not everyone makes it out. To escape a house fire, early warning is vital. That's why every home in Australia needs a smoke alarm.
But with several different types of alarms out there, it can be confusing to know which ones you need in your house. Read on for information that will set you straight – and hopefully prevent you from having to wave the tea towel at a screaming alarm every time you burn your toast.
Types of smoke alarms
There are two main types of smoke alarm for home use: ionisation and photoelectric alarms.
These contain a very small amount of radioactive material, which reacts to particles emitted in a fire and sets off the alarm. Ionisation alarms are best at detecting fast-flaming fires that don't emit much visible smoke. But most house fires tend to be smoky and smouldering, and ionisation alarms aren't as quick at detecting these. They can also be prone to nuisance alarms from cooking, so shouldn't be located near your kitchen.
These contain a photo cell and a light beam shining away from the cell. When smoke enters the test chamber, some of the light is scattered by the smoke particles and hits the cell, triggering the alarm. Photoelectric alarms are best at detecting smoky and smouldering fires. Dust or insects entering the unit can cause false alarms, so they have to be cleaned occasionally.
Other types of alarms
There are two other types of home alarms that are generally used in special situations:
- Carbon monoxide alarms – often used overseas to ensure safe operation of central heating systems.
- Heat alarms – ideal for kitchens.
Even if you have one of these for a special purpose, you should still install a standard smoke alarm as well.
Which type is best?
Photoelectric alarms and dual sensor alarms (which contain both ionisation and photoelectric sensors) are the best type for homes, as shown by our tests and as recommended by most fire authorities. Photoelectric smoke alarms are much faster at detecting smoke than ionisation alarms. Studies have shown that photoelectric alarms typically respond to smoky fires within about three to five minutes. Most ionisation alarms take much longer – up to 20 minutes or more – by which time escape can be much more difficult. Ionisation alarms can be a useful additional level of fire protection, but should not be the only type you have in your home.
What to look for
Standards Australia certification or ActivFire registration
This ensures the alarm complies with the Australian Standard.
These alarms combine both ionisation and photoelectric sensors, providing additional cover. We recommend going for one of these if possible.
10-year lithium battery
Some models come with a pre-installed 10-year lithium battery, which will last for the life of the smoke alarm.
This allows you to check the alarm is working. Some models can be tested by shining a torch on the alarm, others using most household remote controls (such as a TV remote). This eliminates the need to climb a ladder or reach up with a broom handle – especially good for high ceilings or if you're not very mobile.
Pressing this button silences false 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.
Battery-powered models should monitor their own battery level and warn you when the battery needs changing by beeping every few seconds.
Some models feature a light that turns on when the alarm is activated. This is helpful if there's a power failure during a fire, as it can guide you out of the house.
Most mains-powered and some battery-powered alarms can be connected to each other, so that if one goes off, so do the rest.
Features for those with hearing problems
For people with a hearing problem there are special products available, such ultra-loud alarms, strobe lights, and vibrating pads for your bed. For details, contact your state's Deaf Society, Independent Living Centre or fire brigade.
Most modern smoke alarms have insect screens to help prevent insects setting off false alarms.
A basic ionisation alarm can be very cheap – from under $10. A fancier model can be closer to $50. Photoelectric alarms can be found for less than $20, but the more complex ones can cost up to $100.