A BAL 40 rating is the bush fire attack level and made to protect buildings from burning and from direct exposure to flames and high radiant heat.
The BAL 40 rules state the design and types of materials you can use:
- Roofs
- External walls
- Floors & subfloors
- External windows & doors
- Verandas, decks & patios
- Water & gas supply pipes
The BAL 40 requirements can add significantly to the cost of building so be sure to check this.
Please be aware that this article offers guidance only.
Bushfire Attack Level (BAL) | Description of predicted bushfire attack and levels of exposure |
BAL low | There is not sufficient risk to warrant exposure |
BAL 12.5 | Ember attack |
BAL 19 | Increasing levels of ember attack and burning debris ignited by wind borne embers together with increasing heat flux between 12.5 and 19kW/m2 |
BAL 29 | Increasing levels of ember attack and burning debris ignited by wind borne embers together with increasing heat flux between 19 and 29kW/m220 |
BAL 40 | Increasing levels of ember attack and burning debris ignited by wind borne embers together with increasing heat flux with the increased likelihood of exposure to flames |
BAL FZ | Direct exposure to flames from fire front in addition to heat flux and ember attack |



You must seek professional advice and check your intended design complies with Council and code requirements before you go ahead with any building project.
It’s good to check with your council to see on your specific block what your BAL rating is. Once you know that you can go on the hunt for the right building materials and builder.
We recommend if you’re in or around the ACT and NSW especially the south coast to get your block rated and to know where you can build on a rural block is to contact a bush fire assessor. We highly recommend and have used Jeff who is full of wonderful information and reports the work with council in getting your building approved.
Jeff Dau – Principal Consultant at EMBER BUSHFIRE CONSULTING. His qualifications: BAppSc, GradDip Fire Safety Engineering, GradDip Bushfire Protection- Bushfire Protection and Design (Level 2).
0419826282 E.jeff@bushfireassessor.com.au | bushfireassessor.com.au
Image and information used from the below websites:
https://www.bushfireprone.com.au