Building and surviving in bushfire prone land
While bushfires are a natural part of Australian life, strategic management of fire risk and response is vital in protecting people and property. Read on for expert advice from our certified bushfire planners on how to manage building on land which could be at risk of bushfire.
17 June 2020
Q What is bushfire prone land?
Bushfire prone land is forests, grasslands and those areas within 100m of forests and 30m of grasslands that are at significant risk in the event of a bushfire.
Q How do I know if my land is in a bushfire prone area?
Your local council website may have links to a bushfire prone land map and your state fire and/or planning agency may also offer a search of your property to identify if it is bushfire prone land.
Q What does it mean if I want to build within a bushfire prone area?
Each state jurisdiction has a planning framework that guides development in bushfire prone areas. There are some minor developments that are exempt from requiring a bushfire assessment. Generally, a bushfire assessment is required to ensure the siting, design and construction standards of the development will be adequate to lower the risk from a bushfire event.
Q Is it mandatory for me to include an assessment of the bushfire risk in my development application?
If you are building in a bushfire prone land map you usually need a bushfire assessment. There are some exemptions for small developments. You should check with your local government if exceptions apply.
Q What type of assessment do I need?
The type of assessment is determined by the type of development, distances and slopes that will impact the fire behaviour. Generally, proximity to vegetation and impact on vulnerable people will require a more detailed assessment.
Q What does a bushfire assessment involve?
- Building - An assessment is completed to identify separation, bushfire fuel loads, topography and other factors to determine the radiant heat flux that a proposed development could be exposed to. The radiant heat flux determines the Bushfire Attack Level (BAL) and construction requirements.
- Planning - There are six elements that are considered within bushfire planning:
- Setbacks: commonly referred to as ‘asset protection zones’ or ‘defendable spaces’.
- Landscaping: the vegetation and features in and around a building.
- Water provision: appropriate access to reliable firefighting water.
- Access: the ability of occupants to escape and fire authority to access a fire front.
- Hazardous materials: use of construction and design elements that do not contribute to bushfire risk, such as electricity and gas.
- Emergency management: emergency planning arrangements to facilitate shelter onsite and evacuation decisions.
Q Are there different bushfire assessment processes?
Yes, there are two assessment processes that can be implemented:
- Method 1 is a simplified assessment process analysing radiant heat exposure and implementing six simplified steps to determine the Bushfire Attack Level (BAL).
- Method 2 is a detailed and complex assessment process analysing radiant heat exposure and flame length. Site specific inputs such as fire danger index, slope, fuel loads, fire run, flame width and shielding are recorded and used within fire engineering calculations to determine radiant heat exposure and flame length.
Method 2 has increased accuracy as there are less assumptions within the process.
Q What is BAL?
Bushfire Attack Level (BAL) is a way of measuring the severity of a building's potential exposure bushfire. There are six BALs (BAL-LOW, BAL-12.5, BAL-19, BAL-29, BAL-40 and BAL-FZ) as detailed in the Australian Standard 3959 Construction of Buildings in Bushfire Prone Land. Each of these levels specifies the appropriate design considerations and materials to be used for buildings in bushfire prone areas. The National Construction Code has state variations to the Australian Standard that require implementation.
Q Why is landscaping so important for bushfire risk management?
Maintaining the separation between the building and vegetation through appropriate landscaping is essential to lower the risk of building and life loss from a bushfire. Appropriate landscaping – the type of plants and structures, and where they are placed – can reduce the risk of a bushfire moving towards main structures such as homes.
Q How can I be assured of the quality of the assessment?
Fire Protection Association Australia administers the Bushfire Planning and Design Accreditation scheme. Anybody undertaking bushfire assessment should be an accredited practitioner through this scheme. The RPS bushfire team are accredited practitioners.
Q What is a bushfire survival plan?
Each state fire agency has guidelines on how to prepare a bushfire survival plan. The intent is to get the landowner to think through what preparations are required prior to a bushfire event and how they will respond if a bushfire threatens their property. For complex properties that are remote, have several structures or vulnerable people/occupants, assistance from an accredited bushfire consultant is recommended.
Q Who are vulnerable people?
Vulnerable people are those who may be sick, mentally or/and physical impaired, have language difficulties, and/or may be very young or elderly. Vulnerable people may be unaware of their surroundings, lack situational awareness (of bushfire risk) and be unable to self-evacuate. Due to their vulnerability, a higher degree of planning and emphasis on emergency management is required.