The 2009 bushfires that spread through Kinglake and surrounding townships, causing massive loss of life and property, has been said to be Australia’s worst ever natural disaster. In response to this tragedy, in March Victoria adopted a new Australian Standard AS 3959-2009. The aim of this new standard is to improve the ability of buildings to withstand attack from bushfires. This article will provide an overview of the new standard and it means for your next build project.
Bushfire Attack Levels (BALs)
The AS 3959-2009 standard defines new construction requirements based on six, defined “Bushfire Attack Levels (BALs)“. The BAL that your property falls in is determined by a number of factors and is essentially the amount of risk that your property is at in the event of a bushfire attack. The six BALs are a sliding scale of risk starting from BAL-LOW (insufficient risk to warrant specific construction requirements) through to BAL-FZ (Direct exposure to flames from fire front in addition to heat flux and ember attack).
It is important to note that these BALs apply to every new building in Victoria that now must meet the associated BAL construction requirements – this is not just for regional/bushfire affected areas. In majority of inner city and inner suburban areas however, the BAL will most probably be classified as ‘BAL-LOW’.
How are BALs for each property assessed?
There are two methods for assessing a property’s BAL:
1) Simplified method
The Simplified method is a six step site assessment process that can be made by an owner, architect, building surveyor or builder:
- Step one Determine the Fire Danger Index (FDI)
- Step two Determine the site’s vegetation types
- Step three Determine the distance from the site to the vegetation
- Step four Determine the slope of the land under the vegetation
- Step five Determine the BAL
- Step six Apply the construction requirements set out in Australian Standard AS 3959-2009
2) Detailed method
The Detailed method is necessary when the down slope of the subject property is greater than 20 degrees. In this case a qualified Fire Safety Engineer must be engaged to do the assessment.
At what point does BAL compliance get checked?
BAL construction requirements form part of the Building Permit. The BAL assessment and relevant compliant construction methods must be included in the working drawings and associated building permit documentation.
The building surveyor confirms that the BAL assessment is accurate for your property then checks that the appropriate BAL requirements are satisfied in your building permit documentation.
How do the BALs affect build costs?
The higher the BAL, the higher the level of compliance costs. The lowest two BALs may potentially not incur any additional construction costs however for homes being built in the highest BAL-FZ, be prepared to incur anywhere from $30,000 and more in extra build costs.
How do the BALs affect Developers?
It is important to note that because BALs affect individual properties, developers who are building multi-unit residential estates may find that due to the specific location of each dwelling, some dwellings may actually have a higher BAL (& therefore added construction costs) than other dwellings in the same estate. In other words, there is no one BAL for an entire estate.
Useful links
- Building Commission of Victoria’s Guide to assessing your property’s Bushfire Attack Level
- Purchase Australian Standards’ AS 3959-2009 incorporating BALs
- Victorian Bushfire Reconstruction & Recovery Authority Bushfire Rebuilding Frequently Asked Questions
- Housing Industry of Australia (HIA) media release of the new AS 3959-2009 incorporating BALs
About Simone Schenkel
Simone Schenkel is the lead Sustainability Architect with Brutal Art Design + Build. She is part of the 2009 Victorian BAL volunteer program and has been conducting voluntary BAL site assessments in Kinglake, Kinglake West, Whittlesea and Humevale.
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{ 2 comments… read them below or add one }
hi, we are currently in the process of building a new home, and have been hit with a $4000 charge for bushfire assesment
we are planning to build in wattle view estate in broadford, vic.
what would that $4000 be used for? just an assesment or do they actually have to do things to the house, using that $4000?
thanks
Hi Nick,
I’ve asked Simone – our architect and BAL Assessor – to answer your question (below).
Hope it helps,
Adam
——
Without knowing your individual circumstances, normally a Bush Fire Assessment JUST states the bushfire area a certain building is located in and therefore dictates what building measurements must be taken during construction.
Although I have only personally participated in voluntary BAL assessments in King Lake, I understand they typically range between $300 and $500, depending on the difficulty of the site and the travel/consultation time involved (which I wouldn’t imagine to be more than say 6 hours).
I recommend that you contact your assessor and request clarification for the fee.
Is the person doing the assessment also the builder/architect?
In this case the fee might include building specifications according to the Australian Standard regarding the bushfire requirements for construction. Even if this was the case, I would personally think that the cost for this should somehow be included in your detailed working/construction drawings or in the building specifications and not in the BAL assessment itself.
Hope that helps!
Simone