How to Determine Bush Fire Attack Level (BAL Rating)

September 20, 2023

The article discusses the importance of determining the Bushfire Attack Level (BAL) for properties in bushfire-prone areas as Australia prepares for another bushfire season. To comply with Australian Standard 3959:2018, specific building methods and materials must be used to protect life and property. BAL ratings are assigned based on the heat flux exposure a building may face during a bushfire. While it's recommended to have a bushfire consultant assess BAL, a self-assessment can provide an initial indication to find out if this is worthwhile confirming. Here we outline the steps for self-assessment, including determining the vegetation type, measuring the distance from the proposed building to the bushfire hazard, calculating the slope, and identifying the Forest Fire Danger Index (FFDI). By using these factors and reference tables, individuals can determine the approximate BAL for their location.

How to Determine a Bushfire Attack Level (BAL Rating)

The Bushfire Attack Level (BAL) rating is a critical assessment that categorizes the potential bushfire risk for properties in Australia, spanning from LOW to FZ, representing various levels of fire intensity and potential hazards.

To protect life and property, when building in a bushfire prone area, we are required to use certain building methods and materials to satisfy Australian Standard 3959:2018 – Construction of buildings in bushfire-prone areas.

These bushfire prone areas are given different bushfire attack levels (BAL) based on the heat flux exposure of the building in a bushfire situation.

When determining the BAL, it is always best to have a bushfire consultant carry out an assessment, and a professional assessment is likely to be required for any council submission or certification. If you are looking for an initial indication of the potential BAL to pursue your building project, you can complete a self-assessment. To do this, follow the steps below.

Step 1 – Determine the vegetation type

Use the classification of vegetation formations chart to determine the vegetation type.

Image source - NSW Rural Fire Service