What is a Bushfire Attack Level or
BAL Assessment?

Home in bushfire prone area (BPA). Modifications to existing building would require a BAL Assessment.
Home in bushfire prone area (BPA). Modifications to existing building would require a BAL Assessment.

Victoria is one of the most bushfire prone places in the world. Since the tragedy of the Black Saturday bushfires in 2009 and the subsequent royal Commission, many new building regulations were significantly revised to reduce the impact to buildings and save lives when faced with a bushfire attack.

A Bushfire Attack Level or BAL is an assessment under the Australian Standard 3959-2009 Construction of Buildings in Bushfire Prone Areas (BPA’s). The building regulation became more detailed and stringent after 2009. 

If you are in a bushfire prone area then a BAL assessment is required to understand the level of risk that your property faces during a bushfire attack. The building approval process requires it and it must be done before;

  • Building a new building.
  • Modifications to an existing building such as extensions, sheds, patios etc.

Why is it important? 

It will help you to design your property to reduce the impact of bushfire, complete regulation requirements, and define actual project costs considering bushfire resistant construction techniques and materials. 

How does it work?

The Bushfire Attack Level depends on the site characteristics related to the bushfire risk. The factors to consider are:

  • The Fire Danger Index (FDI).
  • The type of vegetation.
  • The property’s proximity to the vegetation.
  • The slope of the site. 

The FDI measures the probability of a bushfire starting, how fast it will spread and how difficult it will be to contain. The vegetation type will define the amount of fuel available in the area, which needs to be determined by a BAL certified ecologist.

There are six BAL ratings, each with its property construction requirements based around the type of materials and extra safety features required. If the BAL number is higher, the radiant heat exposure at the site will be higher, and therefore the construction expenses will be higher to reflect this increased threat. 

  • BAL – Low
  • BAL – 12.5
  • BAL – 19
  • BAL – 29
  • BAL – 40
  • BAL – FZ (Flame Zone)
BAL Rating - Ember Attack and Radiant Heat. Obtained from: Department of Planning, 2022.
BAL Rating – Ember Attack and Radiant Heat. Obtained from: Department of Planning, 2022.

At Treetec our certified BAL ecologists have expertise in Victorian vegetation types and bushfire knowledge that can provide a BAL Assessment to help you to obtain your BAL rating for your designated site.

The BAL assessments can be prepared as a standalone document or integrated into other Arboricultural Services or Ecological Services provided by Treetec.

Contact us for more details on quotes and bookings.

 

Further resources: 

Bushfire Resources – Victorian Building Authority

Vegetation role in bushfires – CSIRO

Bushfire Areas and overlays – CSIRO