These standards are designed to make homes and buildings more resistant to fire and help keep people safe.
Western Australia has one of the driest climates in Australia and is prone to bushfire attacks which have destroyed or damaged homes and devastated bushland.
The specific construction requirements for certain residential buildings in designated bushfire-prone areas are contained in the Building Code of Australia (BCA) and Australian Standard 3959 (the Standard).
If you are not sure if your building work needs to comply, you should discuss the project with the relevant local government or a private building surveyor.
Find a registered building surveyor - Online Licence Search.
What is a bushfire-prone area?
These are areas considered likely to be subject to bushfire. They are usually identified through local government planning schemes and designated by the Fire and Emergency Services Commissioner and shown on the map of bushfire-prone areas.
If you are building in an area where there have been bushfires, but it is not an officially designated bushfire-prone area, it is still a good idea to construct your home to the same standards.
New building work
Before you start designing your home, you should contact your local government to find out what planning and building approvals you may need.
What are the construction requirements in bushfire-prone areas?
The construction requirements will depend on the Bushfire Attack Level (BAL) of your home. Determining the BAL requires an assessment of the surrounds taking into consideration factors such as the slope of the land, types of vegetation and its proximity to any other buildings or structures on the site. This assessment would typically be undertaken by BAL assessor. You may wish to consider using an accredited assessor. You can find a list of accredited Level 1 BAL assessors on the Fire Protection Association Australia website.
There is no guarantee that a building will survive a bushfire on every occasion, this is due to the unpredictable behaviour of fire and extreme weather conditions, however the Standard intends to improve the performance of buildings during a bushfire attack.
The Standard applies to things such as external doors, windows and screens, walls, roofs, flooring, eaves, gutters and downpipes.
Structures such as garages, carports, decks or verandahs that are attached or adjacent to your house could be subject to bushfire construction requirements also.
At the end of the assessment, your property will be assigned one of the below BALs.
| Bushfire Attack Level | Description of risk and levels of exposure |
|---|---|
BAL – LOW | There is insufficient risk to warrant specific construction requirements. |
BAL – 12.5 | Risk of radiant heat is considered low. Primarily risk of ember attack. |
BAL – 19 | Risk is considered moderate. Increasing levels of ember attack and burning debris ignited by windborne embers together with increasing heat flux between 12.5 and 19 kW m2. |
BAL – 29 | Risk is considered high. Increasing levels of ember attack and burning debris ignited by windborne embers together with increasing heat flux between 19 and 29 kW m2. |
BAL – 40 | Risk is considered very high. Increasing levels of ember attack and burning debris ignited by windborne embers together with increasing heat flux with the increased likelihood of exposure to flames. |
BAL FZ | Risk is considered extreme. Direct exposure to flames from fire front in addition to heat flux and ember attack. |
A registered building surveyor can advise on specific construction methods that can be included in the design of your home.
Upgrading or rebuilding following a bushfire
An area might be designated as bushfire-prone after your original home was built. If you plan to rebuild or upgrade your home, you may need to bring it into line with the requirements of the BCA and standards, a building surveyor can advise you on this.
Even if your building work is not in a designated bushfire-prone area, it is still a good idea to have a BAL assessment done and build to the standard.
Getting the approvals you need to upgrade, repair or rebuild will be similar to applying for building approval for a new house. After a bushfire, many local governments will help to ensure your application is processed quickly.
Retrofitting existing homes
Building standards and regulations are generally not retrospective. If you buy an existing house in an area that has been declared a designated bushfire-prone area after the house was built, you may not be required by law to upgrade it to the new standards.
If you are thinking about additions or extensive renovations to your home, your local government, building surveyor or other appropriately qualified practitioner can give you advice on whether your home needs to be upgraded and what design features would make it more fire-resistant.
If you are thinking of purchasing an existing house in or near bushland, even if it has not been designated as bushfire-prone, it is a good idea to have a bushfire assessment done prior to making an offer.
This will help you make an informed decision on whether the house is adequately protected against bushfire and what you would need to do if you want to upgrade or rebuild.
How can I retrofit my existing home?
The work of retrofitting an existing home may require a building permit from your local government.
These are just some examples of building retrofits for homes up to and including BAL 29. If your BAL is higher than BAL 29, you will need to seek the advice of a building surveyor or other appropriately qualified and experienced practitioners.
Flooring
To prevent burning embers entering under the floor space, any raised floors should have the perimeter enclosed with non-combustible material. For example, a timber-framed house on stumps should have the area between the floor and the ground covered with material such as masonry, concrete or non-combustible sheeting or timbers that are naturally fire-resistant or treated with a fire retardant.
External doors and windows
Burning embers and smoke can enter a house through external doors and windows.
To prevent this from occurring:
- External side-hung doors should be:
- non-combustible or made of solid timber with a minimum thickness of 35mm;
- sealed with weather strips or draught seals;
- protected with metal screens, either mesh or perforated sheet, made of corrosion-resistant steel, bronze or aluminium; and
- tight-fitting with any gaps between the frames and walls sealed.
- Sliding doors should be protected with metal screens, either mesh or perforated sheet, made of corrosion-resistant steel, bronze or aluminium, or fitted with bushfire shutters.
- Windows should be protected with metal screens or bushfire shutters.
- If metal screens or bushfire shutters are not fitted to windows and external doors, glass should be toughened safety glass.
- Frames supporting the mesh screens for both doors and windows should be made of metal or bushfire-resisting timber.
- All external hardware for windows and external doors should be made of metal.
External walls
It is recommended that all external walls be constructed of non-combustible material such as masonry or concrete.
Existing timber or steel framed homes may be able to be retrofitted with fire-resistant wall cladding or timber that is naturally fire-resistant or treated with a fire retardant.
Gutters and downpipes
Non-combustible gutter and valley leaf guards can help to prevent embers igniting leaf litter in your gutters. Gutters should be made of non-combustible material and box gutters flashed at the junction with the roof. The standard does not set out specific construction material requirements for downpipes.
Roofs
Roofs, roofing systems and accessories should be non-combustible, and the roof/wall junction should be sealed to prevent gaps. Ember guards made of mesh or perforated sheet, constructed of corrosion- resistant steel, bronze, or aluminium, should be fitted over roof ventilation points such as gable and roof vents.
Evaporative air conditioners
During a bushfire, burning embers can be blown very quickly over long distances.
Even if your home is not in direct danger from the fire, burning embers can be drawn into and ignite an evaporative air conditioner. The resulting fire can spread fire into the roof or ceiling space and considerably damage or even destroy your home.
Fit your evaporative air conditioner with non-combustible covers (ember protection screens) with a mesh or perforated sheet with a maximum aperture of 2mm, made of corrosion-resistant steel, bronze or aluminium.
New evaporative air conditioners
Before you install a new evaporative air conditioner, make sure that the unit complies with the ember protection requirements.
Who can I contact to undertake an inspection of my property?
An assessment of your property should be carried out by a qualified person with experience in bushfire design and/or management. Your building surveyor will rely on the bush fire assessment to determine the appropriate construction requirements for your building and may either carry out the assessment, or refer you to a suitably qualified practitioner.
Downloads
Links
- Department of Fire and Emergency Services
Map of bush fire prone areas and other bush fire safety advice - The Victorian Building Authority
Information on retrofitting existing homes located in bushfire areas - Standards Australia
Standards can be purchased online, however, a registered building surveyor or appropriately qualified practitioner can advise you on the requirements of AS 3959.
