Following are extracts from WA Planning documentation showing how a BAL assessment is calculated using AS3959 2018 Method 1.

The following example shows why all  classified vegetation 100 metres or greater from a structure is considered LOW risk.

BAL_1

BAL LOW no building modifications required.

The following example shows why a BAL (in this case BAL 29) rating would apply.

BAL_1

BAL 29  building modifications to gain compliance will be required.

The following is a visual guide with an explanation of each BAL rating. Guide refers to AS3959-2009, AS3959 2018 now applies.

BAL_3