Bushfire Protection Building Regulations
Building in Victoria
In the wake of the Victorian bushfires of February 2009, the Victorian Government has introduced new building regulations (AS 3959 Construction of buildings in bushfire-prone areas) to ensure that new homes, as well alterations and additions are designed with greater bushfire protection.
The new regulations/standard has 6 levels of risk assessment - known as bushfire attack level (BAL). The BAL categories rank sites from low to extreme (see table below). Sites in the high to extreme zones have increased construction requirements in terms of ember protection, as well as from direct flame contact.
|Bushfire Attack Level (BAL)
||Description of Levels of Exposure|
Predicted Bushfire Attack
||Insufficient risk to warrant specific construction requirements (approximately 80% of buildings will fit into this classification)|
||Increasing levels of ember attack and burning debris ignited by windborne embers together with increasing heat flux between 12.5 and 19kW/m2|
|| Increasing levels of ember attack and burning debris ignited by windborne embers together with increasing heat flux between 19 and 29kW/m2|
|| Increasing levels of ember attack and burning debris ignited by windborne embers together with increasing heat flux with increased likelihood of exposure to flames|
|| Direct exposure to flames from fire front in addition to heat flux and ember attack|
ALL of Victoria has been deemed a 'bushfire prone area', thus all new residences in Victoria are subject to the standard.
**Important to note- the new standard does not guarantee building survival, it is designed to improve the ability of the building to withstand the fire front and give occupants a level of protection while the front passes.
Part of the process of building or rebuilding will involve obtaining a BAL assessment, either on paper, or with a site visit for high risk areas. Once the site has been assessed the design can commence with the relevant construction methods. Once the design is complete a building permit can be obtained. No permits can be obtained without without the BAL assessment.
Information regarding rebuilding and retrofitting your home is available at the
Building Commission website.
Several building types have been mentioned as acceptable for the highest BAL rating, those being mudbrick, masonry, brick veneer, concrete and aerated concrete, provided they have either a minimum thickness of 90mm, an FRL of -/30/30, or have been tested for bushfire resistance to AS1530.8.2.
Interestingly strawbale has not be mentioned to date. There have been CSIRO tests done on straw bale walls in Australia in conjunction with members of Ausbale, but they appear to be outdated due to changes in the heat flux temperature for testing going from 29kW to 40kW in the new BAL ratings (BAl 40 and BAL FZ).
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