What is a Rating?
A Bushfire Attack Level (BAL) Assessment is a means of measuring the severity of a building’s potential exposure to the three different ways a bushfire can attack a property – ember attack, radiant heat and direct flame contact. To learn more about how these can impact a property see our article here: How a Bushfire attacks your home.
In essence a BAL assessment uses the methods found in AS3959 to measure the risk of a house being impacted by a bushfire event . The BAL assessment will then give a rating that classifies the potential exposure and risk as BAL Low meaning minimal risk or one of 5 other classification as shown in the image below. The higher the number, the greater the risk. BAL-FZ or Flame Zone has the highest risk. The number relates to the radiant heat the building is likely to be exposed to, measured in kilowatts per square metre. Therefore a BAL 12.5 rating means that the calculated radiant heat exposure will be up to 12.5 kilowatts per square metre.
Once the BAL rating is known, a building’s construction can then be adjusted to reduce the possibility a house will be destroyed in a bushfire.
To learn more about what each of these BAL levels mean and the affect they can have on the construction of your building see our other articles here:
- How a BAL Rating is calculated.
- What does a BAL rating mean for my house design?