Smoke Detectors

Smoke Alarms

Smoke alarms are very important domestic safety devices. Residential occupancies account for most fire fatalities where most of these occur at night during sleeping hours. The risk of death from fire in a home is up to three times higher in homes without smoke alarms when compared to homes with smoke alarms. In Queensland, nearly 80% of all home fire deaths occur in homes without smoke alarms and almost 50% of deaths occur between 12am - 8am when people are sleeping. Smoke alarms are designed to give an early warning of fire so occupants have a greater chance of escape.

Smoke alarm legislation has already resulted in more lives being saved in other states where smoke alarms have been made compulsory. New Queensland laws are similar to arrangements in New South Wales and Victoria which require that owners of all homes and units (Class 1 and sole occupancy in Class 2 buildings) to install and maintain smoke alarms in all older (pre 1997) homes by 1 July 2007.

Since 1 July 1997 in Queensland, it has been mandatory under the Building Code of Australia 1996 to have hard-wired (240 volt) smoke alarms installed according to Australian Standard (AS) 3786, in residential homes built or significantly renovated (exceeding 50 percent of the original building).

From 1 July 2007, owners of all houses and units in Queensland must install and maintain a smoke alarm.

From 1 July 2007, a lessor or agent will be required to install smoke alarms in all rental properties, the minimum legal requirement being a 9 volt battery operated smoke alarm with a one year battery.

To ensure compliance, on the sale of a property from 1 July 2007, the vendor will have to lodge a Form 24 with the Queensland Land Registry stating that smoke alarms are installed in the property and that the purchaser has been informed that alarms are installed. Fire Officers will investigate complaints received about residential non-compliance. There will be a maximum fine of $500 for failing to install and maintain smoke alarms by 1 July 2007

A lessor or agent must test and clean each smoke alarm within 30 days before the start of a tenancy. In addition, a lessor or agent must replace, in accordance with manufacturer's instructions, each battery in the smoke alarm the lessor or agent is aware is almost flat within 30 days before the start of a tenancy.

The lessor or agent must also replace the smoke alarm unit before it reaches the end of its service life as indicated by the warranty offered by the manufacturer. If the smoke alarm reaches the end of its service life, the lessor or agent must replace it immediately. Should the smoke alarm appear to fail, other than because the battery is flat or almost flat, the tenant must advice the lessor or agent as soon as practicable.

A lessor or agent is only required by law to test and clean smoke alarms at the start of a tenancy. Tenants are required by law to test and clean each smoke alarm in the dwelling at least once every 12 months. Tenants are also required by law to replace, in accordance with the information statement that is provided to the tenant, each battery that is flat or almost flat. Where the tenant becomes aware that a smoke alarm is not working, other than because the battery is flat or almost flat, they must advise their landlord or agent as soon as possible whereupon the landlord should have the smoke alarm checked, repaired or replaced by a licensed professional

Queensland Fire and Rescue statistics indicate fires have been attended where the smoke alarm has not operated because batteries were flat or removed. Therefore, it is recommended that lessors consider installing alarms that are more reliable than the basic alarm.

There are a number of ways in which smoke alarms can be powered:

9 Volt Smoke Alarms (battery operated stand alone)


• Easy to install
• Test button to ensure correct operation
• Low battery indication
• In some models a hush button to stop nuisance alarms
• Battery missing indicator
• Tested by Scientific Services Laboratories to comply with AS3786
• Some models can be interconnected


Battery needs to be replaced yearly

9 Volt Long-Life Smoke Alarms (battery operated stand alone)

These can either be renewed or are non-removable lasting the life of the alarm, up to 10 years. This avoids the need for the householder to replace the battery annually. In some models, the battery cannot be removed due to the unit being sealed.


• Easy to install
• Batteries do not need to be replaced as regularly
• Some models available with a sealed, tamper-proof battery


• More expensive

240 Volt Smoke Alarms (hard-wired)

A 240 volt smoke alarm is connected to a home's electrical system and has battery back-up power supply.


• Considered more reliable in the longer term
• Early warning - occupants alerted in the shortest possible time
• Uses a battery to provide back-up power if the AC power fails
• Models can be interconnected which sound alarms in all connected units
• Can come with a long life Lithium Battery - built-in and tamper proof
• Power-on indicator
• In some models a hush button to stop nuisance alarms
• Test button to ensure correct operation
• Tested by Scientific Services Laboratories to comply with AS3786
• Some can be purchased with a rechargeable battery (non-replaceable)


• More expensive
• Need to be installed by a qualified electrician

There are two kinds of smoke alarms:

Ionisation Smoke Alarms

This type detects invisible particles of combustion e.g. from cooking toast. They activate more quickly for fast, flaming fires and little visible smoke.


• Cheaper than other types
• Very good with fast flaming fires with little visible smoke
• Suitable for general use
• Less prone to false alarms due to dust and steam


• Very susceptible to nuisance alarms due to cooking
• May be slow to respond to slow smouldering fires
• Contain radioactive material

Photoelectric Smoke Alarms (also known as optical)

This type detects visible particles of combustion e.g. smouldering cigarette smoke. They respond to a wide range of fires, but they are particularly responsive to smouldering fires and the dense smoke given off by foam filled furnishings or overheated PVC wiring.


• Good for smouldering fire and dense smoke
• Not as prone to cooking nuisance alarms
• Contain no radioactive material
• Suitable for general use


• Prone to nuisance alarms from dust and insects
• More expensive

Queensland Fire & Rescue Service recommends buying an alarm which carries the Standards Australia Mark or is Scientific Services Laboratory (SSL) labeled. According to legislation smoke alarms installed must comply with AS 3786-1993.

Protection against fire increases with the quality and type of smoke alarm that is installed. Research indicates that photoelectric smoke alarms are generally more effective than ionisation types across a wider range of fires experienced in homes. For this reason, QFRS recommends that photoelectric smoke alarms be installed, especially if you are installing only one alarm. If you already have smoke alarms installed, QFRS recommends that you supplement the existing alarms with photoelectric types, especially between sleeping areas and exits from your home (e.g. hallways); and at the end of the service life of existing smoke alarms, replace them with photoelectric types.

Smoke alarms can be installed either stand alone or interconnected. Interconnection allows all smoke alarms to sound simultaneously should any one alarm activate. All occupants are alerted, maximising the opportunity for escape. Children's bedrooms should have a smoke alarm, and be connected to the parent's bedroom because children sleep much sounder than adults.

As a legal minimum requirement, there must be one alarm outside sleeping areas and one alarm on each level of the home:
• Between any area containing bedrooms and the rest of the house or unit e.g. hallways;
• On a storey not containing bedrooms on the most likely evacuation route from the storey.

Queensland Fire and Rescue Services strongly recommend installing additional alarms. In cases where occupants sleep with the door closed, it is especially recommended that an alarm be installed in each bedroom.

Because smoke rises, smoke alarms should be placed on the ceiling. If that is not possible, it may be positioned high on a wall, according to the manufacturer's instructions. Every residence is different. The following is suggested as a guide:
• A smoke alarm outside each sleeping area and on each level of the home provides a minimum degree of protection from the threat of fire
• In a single-level home, one alarm may be sufficient (as a minimum) if all the bedrooms connect to a common Hallway
• Additional alarms are needed in homes with separated sleeping areas
• Where occupants sleep with bedroom doors closed, install a smoke alarm in each bedroom and the hallway.

To maximise smoke alarm operation avoid installation in the following positions:

• In dead air space. This is an area in which trapped hot air will prevent smoke from reaching the alarm. This space generally occurs at the apex of cathedral ceilings, the corner junction of walls and ceilings, and between exposed floor joists
• Near windows, doors, fans or air conditioners. Excessive air movement may prevent smoke and gases from reaching the smoke alarm or cause nuisance alarms
• In or outside of the bathroom as steam may cause nuisance alarms
• Closer than 1.5 metres to fluorescent fittings as electrical ‘noise' or flicker may affect the smoke alarm
• In kitchens. If there is no alternative, a photoelectric type is preferred
• In insect infested areas, as insects flying into the alarm could cause nuisance alarms

Maintaining and Replacing Smoke Alarms

• Once a month check the battery by pressing the test button. If you cannot reach the button easily, use a broom handle
• Keep them clean. Dust and debris can interfere with their operation, so vacuum over and around your smoke alarm regularly
• Replace the batteries at least once a year. Pick a memorable day (e.g. a public holiday, anniversary or your birthday) and replace the batteries each year on that day. In most models when batteries are low the detector will sound a short 'BEEP' every minute or so. This is your reminder to replace the batteries
• Smoke alarms must never be painted
• If cooking and smoke sets off the alarm, do not disable it. Turn on the range fan, open a window or wave a towel near the alarm
• Do not remove the batteries from your smoke alarm
• Smoke alarms wear out over time. They should be replaced prior to the expiry date on the manufacturer's warranty. You may want to write the purchase date with a marker on the inside of the smoke alarm unit. That way, you'll know when to replace it
• All types of smoke alarms have a limited life-span and need to be replaced according to manufacturer's instructions.

Further information on smoke alarms is available by phoning 1300 369 003 or visiting the Queensland Fire & Rescue website at

See also Smoke Detectors