What is a BAL Rating?

January 31, 2023 Adam Blumfield

A BAL Rating is a Bushfire Attack Level.

This is the rating system the Australian Standard (AS-3959) Construction of building in a bushfire prone area uses to assess the risk your home is to the effects of a bushfire and grassfire. It also dictates the construction methods and materials that are required to be used for the construction of your home.

The Bushfire Attack Level is based on heat flux exposure thresholds and this takes into account the landscape of your property (Flat Land, Upslope, Downslope). The type of vegetation surrounding your property (Forest, Woodland, Shrubland, Scrub, Mallee/Mulga, Rainforest, Grassland)

Purple Building Group is a Custom BAL Builder in Eltham, Diamond Creek, Christmas Hills and throughout North East Melbourne

BAL – LOW No additional construction methods required

BAL – 12.5 The structure is at risk of ember attack and heat flux to 12.5Kw/m2

BAL – 19 Increasing levels of ember attack and heat flux to 19Kw/m2

BAL – 29 Increasing levels of ember attack and heat flux to 29Kw/m2

BAL – 40 Increasing levels of ember attack and heat flux to 40Kw/m2

BAL – FZ Flame Zone. Direct exposure to flames from fire front in addition to ember attack and heat flux over 40Kw/m2

To obtain a BAL Rating, your site will need to be assessed by an accredited Bushfire Planning and Design Practitioner.

It is important to obtain an experienced provider that will discuss your property with the CFA (or other referral authority) if it does involve more complexities than a traditional building envelope. If the CFA rejects your proposal, in some cases it is possible to come to an “alternative solution” to meet the requirements of the Australian Standard.

For our own home we had the CFA reject our building proposal as there was a difference of opinion regarding the landscape between our Bushfire Practitioner and the CFA. Our Bushfire Practitioner told us that there was no way to discuss the outcome with the CFA. He was wrong.

We went to engage the services of a more experienced Bushfire Practitioner who provided a more detailed report of every facet of our property landscape and further beyond. His bushfire knowledge was impeccable (Feel free to email me for his contact details). After a site meeting with the CFA, the Bushfire Practitioner, Town Planner and Council, we had a somewhat successful outcome to the original design. We only got this outcome due to the experience of our new more experienced Bushfire Consultant.

Based on your BAL Rating, additional construction elements may be required. If you’re building in a Bushfire Prone Area it is important to use a builder with a good understanding of the requirements in building in a Bushfire Prone Area.

Generally speaking, up to BAL 19, significant increases to costs should not occur. BAL 29 will require some upgrades to windows, doors and the types of timber you can use externally. BAL 40 and BAL FZ can add significant costs due to the types of certified materials that are required to be used. I feel there are too many variables to specify an estimated dollar amount.

If you are looking to build your new home in a Bushfire Prone Area, contact us at Purple Building Group. We have the knowledge to provide assistance for your Bushfire Construction.