If you live near bushland your home may be exposed to high levels of radiant heat or flame contact in a bushfire. In bushfire-prone areas a bushfire attack level (BAL) assessment is required as part of some planning and building regulations.

The BAL can help determine the requirements for construction.

You should have your home assessed by a qualified bushfire practitioner. They should use AS 3959 to determine a BAL rating. Knowing your BAL can help you improve the resilience of your home.

You should consider building or renovating to a higher BAL than your home is assessed as being. This will make your home more resilient to the effects of a bushfire.

Bushfire Attack Level (BAL) is a system used in Australia to assess the bushfire risk of a property. By assessing the risk of being impacted, BAL informs building construction in bushfire-prone zones. All new homes in bushfire-prone areas must have a BAL assessment. For older houses, a BAL may not be available. A BAL assessment is beneficial as it helps you understand your bushfire risk and provides information on how to retrofit a home to improve resilience.

• BAL Low: House is in a place where risk of bushfires are low. Therefore, use of specific construction materials are not required.
• BAL 12.5: There is a chance of embers reaching the house and resulting in ignition.
• BAL 19: The risk is higher. Potential for more embers that could result in ignition with increasing heat flux.
• BAL 29: Lots of embers, more heat, and even debris that could be blown towards your house.
• BAL 40: Increased risk. Expect lots of embers, more heat, and there is a good chance flames could reach your house.
• BAL FZ: This is the highest risk. It means your house could be right in the middle of a fire, with flames touching it and everything getting extremely hot.

Each BAL rating relates to specific construction requirements. Therefore, obtaining a BAL for your house is important to select construction materials appropriate to your BAL 

A water supply dedicated to fire fighting from the main water supply to your house. Alternatively, a second outlet used for fire fighting purposes with suitable fittings to your State or Territory emergency services can be installed into your water supply tank.

Water is a valuable resource, especially during bushfire season. Installing an appropriate system of water storage tanks, pumps, hoses, pipes, plumbing, fittings, and sprinklers using non-combustible materials may enable the defence of your home in a bushfire event.

When designing a system, consider:

• water storage tanks that are rated for bushfires
• pumps that have sufficient flow capacity (400 litres per minute)
• shielding pumps from radiant heat, ember attack, and flames
• location - will you be able to access the system when you need to

If you have a system in place:

• consider if your system is suitable for your needs
• do you have sufficient water storage capacity?
• is your pump protected from radiant heat, ember attack, and flames?
• does your fire fighting pump have a sufficient flow rate?
• are your storage tanks bushfire rated?
• maintain the installation in good working order

Ensure sufficient water is stored before and during bushfire season

Bushfire shutters may be used for window or door protection for the various Bushfire Attack Levels, (BALs), however:

• they must protect the entire assembly (including frames, stills and glazing)
• materials must be consistent with the BAL requirements
• they must be fixed to the building and not be removable
• they must be manually operated at the building (inside or outside), and any motorised system must have backup power supply rather than mains power alone
• gaps in shutters should not be greater than 2mm, but the surface may be perforated up to 20% of the overall shutter surface. 

Combustible window components, frames and seals can ignite when exposed to:

• ember attack
• flame contact
• radiant heat attack. 

Glazing can crack or shatter when exposed to radiant heat or flame, depending on the duration and intensity of the exposure. Damaged glazing increases risk for ember attack entry in your house, this can ignite internal furnishings. The gaps in the screens must be less than 2 mm to prevent small embers from passing through and making contact with the glass and frames.

The materials used in the construction of your home should be appropriate for the BAL. They should also comply with the requirements of AS 3959. This is important as some construction materials are more vulnerable during a bushfire. They may only be suitable for a lower BAL.

Non-combustible and non-toxic materials should be used. This includes for the house, carports, pergolas, patios, sheds, fences and retaining walls. This includes non-combustible:

• Roof and wall cladding
• Wall and roof framing
• Internal wall linings and ceilings
• Insulation, and
• Flame-resistant sarking.

Non-combustible building membranes can provide secondary protection for walls and roof spaces. AS 3959:2018 specifies building membranes with a flammability index of less than 5. Testing has shown that breathable, non-combustible membranes are more effective, and can withstand a greater level of heat exposure. Speak to your builder to decide. Incorrectly specified and installed non-combustible membranes can lead to condensation issues.

Most materials on the exterior of buildings will need to be non-combustible or fully tested to the appropriate. You should seek advice from your builder or local government before starting.