Your level of bush fire risk influences the compliance requirements surrounding your development. The greater the risk, the more protection you must provide. This risk is determined by the bush fire attack level (BAL).
Your level of bush fire risk is influenced by many factors, such as:
- The development location;
- The gradient of the land;
- Vegetation type, and
- Distance of vegetation in relation to the development property.
Before your planned development can proceed, your BAL must be calculated and presented to your local council in a written report called a bushfire risk assessment. To avoid delays in development, it’s advisable to appoint a qualified bushfire consultant to compile your bushfire risk assessment.
Calculating Your Property’s BAL
A BAL rating is calculated under the methodology outlined in the Australian Standard AS 3959–2009. The Standard outlines two distinct methods: the basic procedure (Method 1) and the more detailed procedure (Method 2).
Method 1:
- Perform a site study of all vegetation within 150 metres of the proposed development site.
- Classify all categories of vegetation in the surrounding area.
- Determine the distance between the classified vegetation types and the planned development.
- Determine the slope gradient affecting specified vegetation zones.
- Consolidate the data to determine the BAL of the proposed or existing development site.
Method 1 is not valid in circumstances where the slope gradient under the identified vegetation is greater than 20 degrees on the downward slope. In that case, Method 2 will be employed. A BAL Report-Method 2 is essentially a thorough evaluation utilising mathematics to provide a more precise BAL rating.
Method 2:
A BAL Report-Method 2 is a thorough evaluation utilising mathematics to provide a more precise BAL rating. Method 2 evaluations are often used when it is not feasible to mitigate a rating inside the bounds of your own property.
- Determine the applicable Fire Danger Index and wind velocity.
- Analyse the species, classifications, fuel loads, and height of vegetation zones surrounding the development site.
- Determine the slope gradient affecting specified vegetation zones.
- Determine the slope of the ground between the location development site and the vegetation zones.
- Determine the site’s distance from specified vegetation zones.
- Calculate the length of the flame.
- Determine elevation according to elevation receiver readings.
- Calculate radiant heat flux.
- Consolidate the data to determine the BAL of the proposed or existing development site.
No matter which method is employed, Your bushfire risk assessment must outline suitable building requirements according to BAL and submit a Bushfire Management Plan and a BAL Contour Map, if necessary. This is where the valuable experience and in-depth reporting and analysis of qualified bushfire consultants come into play.
Get Your Bushfire Risk Assessment Today
Treescience’s team of bushfire consultants are accredited in Bushfire Planning & Design (BPAD) from the University of Melbourne. Our Level 2 and 3 consultants are qualified Bushfire Risk Assessment Practitioners (AQF Level 8). Treescience delivers a specialised understanding of bushfire risk assessment in an urban development context and the ability to implement applicable planning and development according to Australian compliance and safety standards.
If you require bushfire risk assessments for any residential, commercial, government and sub-division developments, get in touch today.