BAL 101: Everything you need to know about Bushfire Attack Level Assessments in WA
If you’re planning to build or develop land in a designated bushfire-prone area of Western Australia, one of the first things you’ll need to consider is your Bushfire Attack Level, or BAL. This classification is used to measure the potential exposure of a building to ember attack, radiant heat, and direct flame contact in the event of a bushfire. BAL assessments are a critical part of the planning and building approval process, ensuring developments are appropriately designed to reduce bushfire risk and improve occupant safety.
What is a BAL Assessment?
A BAL Assessment is a site-specific evaluation of how vulnerable a proposed or existing building is to bushfire exposure. It considers three key elements:
Vegetation Type – The kind of vegetation present near the site (e.g., forest, shrubland, grassland) based on AS 3959 classifications.
Distance to Vegetation – How close the proposed structure is to the classified vegetation.
Effective Slope – The slope of the land under the vegetation, which influences fire behaviour and rate of spread.
The combination of these factors determines the intensity of bushfire attack the site is expected to experience and what construction measures are required.
BAL Ratings Explained:
There are six BAL ratings under AS 3959:2018 (the Australian Standard for Construction of Buildings in Bushfire-Prone Areas. It sets out the determination process and construction requirements), each representing a different level of potential exposure to bushfire. These ratings guide what construction standards must be applied.
BAL–LOW: Low bushfire risk. No specific construction requirements apply, but general awareness of fire risk is still recommended.
BAL–12.5: Relatively low risk of ember attack. Construction must include measures like ember-resistant shutters and installation of weather strips.
BAL–19: Moderate risk, with increased likelihood of ember attack and some radiant heat. Requirements include bushfire-resistant joinery, sealed gaps, and fire-rated materials.
BAL–29: High risk, with greater exposure to radiant heat. Construction must resist ignition from embers and radiant heat, including upgraded glazing, insulation, and cladding.
BAL–40: Very high risk, with significant threat from ember attack and potentially direct flame contact. Extensive bushfire construction measures required.
BAL–FZ (Flame Zone): Extreme risk. Direct exposure to flames, high radiant heat, and ember attack is expected. Only specially designed and certified building systems may be permitted, and additional planning controls are often triggered.
When Is a BAL Assessment Required?
A BAL Assessment is typically required:
When a property is located within a designated Bush Fire Prone Area (BPA)—you can check this via the DFES mapping tool.
For any new building, renovation, or development application in a BPA.
At the time of applying for a Building Permit, and possibly when applying for Development Approval (DA), or Subdivision.
When there is a change of land use or intensification of site use (e.g., a new dwelling, grouped housing, or commercial premises) within a BPA.
Who Can Prepare a BAL Assessment?
Only individuals accredited through the Bushfire Planning and Design (BPAD) scheme are authorised to carry out formal BAL Assessments in Western Australia. The levels of accreditation include:
Level 1: BAL Assessments.
Level 2: More detailed assessments including contour maps and Bushfire Management Plans.
Level 3: Complex or performance-based assessments (e.g. vulnerable uses, non-compliant proposals).
At Bushfire Smart, our team has accredited practitioners who cover the whole suite of project needs, and are trained and experienced in applying the bushfire planning framework to both residential and commercial projects.
What Happens After You Receive a BAL?
Once you’ve received your BAL Assessment, the results must be integrated into your building or development plans. A higher BAL rating means your proposed structure will require enhanced construction methods to mitigate fire risk, such as:
Fire-rated roofing and cladding materials
Upgraded window and door systems with metal screens or double glazing
Sealing of all external openings (vents, weep holes, gaps)
Installation of ember guards and non-combustible decking
Specific setbacks or siting adjustments in accordance with bushfire protection criteria
These requirements are typically applied through AS 3959 construction standards and must be shown in your building drawings before council approval can be granted. Ensure your builder understands the bushfire construction requirements and can build accordingly to avoid non-compliance.
Need Help Navigating BAL Requirements?
Understanding your BAL rating is the first step in planning a safe and compliant development in a bushfire-prone area. If you're unsure which assessment you need—or what to do once you receive one—our team can help. We offer site inspections, BAL Assessments, and full Bushfire Management Plans (BMPs) tailored to your development type and location.
Contact us to request a BAL Assessment or get advice on what’s required ➜