Approved Plans - RAL22/0026

Bushfire Hazard Assessment & Management Plan v1                                  NCES REF: J001050
Lot 3 on RP131369 – 96 Black Mountain Range Road, Black Mountain



                  society will not accept this risk and measures are to be put in place to reduce
                  risks to at least a tolerable level.
Assessment Benchmark 4 of the SPP Bushfire 2019 references radiant heat flux exposure of
<29kW/m² on any part of the building as generating an Acceptable to Tolerable level of risk.
AS/NZS ISO 31000:2018 defines ‘Likelihood’ as the chance that something might happen.
Likelihood can be defined, determined, or measured objectively or subjectively and can be
expressed either qualitatively or quantitatively (using mathematics ). The following ‘likelihood’
categories for the probability of the assessed bushfire attack mechanisms impacting the
assessment area have been adopted within this assessment:
      •    Likely - Will probably occur
      •    Unlikely - Could occur but doubtful
The determination of whether a bushfire event is likely or unlikely to occur (i.e., impact the
site) has been based on the relative position of hazardous vegetation to the site. Hazardous
vegetation located upwind of the site under typical south-east Queensland (SEQ) seasonal
fire winds; from the 225º south-west to 0ºnorth, is deemed to expose the site to a ‘likely’
probability of impact should a fire run occur from these directions. Hazardous vegetation
located downwind of the site under typical SEQ seasonal fire winds; 1º north to 224º south
south-west, is deemed to expose the site to an ‘unlikely’ probability of impact.

4.2       Risk from Identified Hazardous Vegetation
The Plan of Development depicts building envelopes within the proposed Lots which will be
primarily flanked by hazardous vegetation to the north, south, and west. The likelihood of a
fire approaching from the northwest, west, and southwest is considered likely, given dominant
regional fire weather winds are derived from the north-west to south-west.
The degree of separation offered to the adjoining vegetation is the primary driver of the
assigned level of risk and was determined with consideration to the Flamesol modelling output
presented in Section 3.3. In the absence of an appropriate separation buffer to the adjacent
vegetation, and implementation of relevant AS3959-2018 construction standards, the future
dwellings on the site could be exposed to direct flame, severe radiant heat and ember attack
during the modelled bushfire conditions resulting in total structure loss.

The Plan of Development provides a minimum 39m setback between the proposed building
envelopes and the closest hazardous vegetation (VHC 24.1 Acacia Open Forest) to the south-
west. 29.3m is the minimum separation required to ensure the proposed building envelopes
on the Lots 1 & 2 are exposed to <29kW/m² radiant heat flux as per the Flamesol modelling
presented herein.

The extent of proposed separation comprises land within the lots and the adjacent Black
Mountain Range Road reserve which is considered a reliable permanent low threat zone for
the life of the development. The Plan of Development therefore facilitates an acceptable risk
of radiant heat impact to the building envelopes thereby satisfying Assessment Benchmark 4
of the SPP Bushfire 2019.




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