Bushfire Hazard Assessment & Management Plan v2 - 30 Pottery St Pomona 2021

Bushfire Hazard Assessment & Management Plan v2                                    NCES REF: J000864
Lot 496 on MCH591 – 30 Pottery St, Pomona



                  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 north to north-west to west to south-west are deemed to be exposed to a
‘likely’ probability of impact. Hazardous vegetation located downwind of the site under typical
SEQ seasonal fire winds are deemed to be exposed to an ‘unlikely’ probability of impact.

4.2       Risk from Identified Hazardous Vegetation
The Plan of Development depicts the building envelope within proposed Lot 8 (Stage 1) and
Lots 9 and 10 (Stage 2) as immediately flanking the identified hazardous vegetation to be
retained within the west of the site. The likelihood of a fire approaching from the west 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 dedicated Asset Protection Zone setback of 19m to VHC
9.1 open Eucalypt forest to the west of the Lot 8 - 10 building envelopes and includes a
trafficable firebreak. >17.2m separation is the maximum separation required to ensure the
proposed building envelopes on Lots 8-10 are exposed to <29kW/m² radiant heat flux as per
the Flamesol modelling presented herein. The extent of proposed separation therefore
facilitates an acceptable risk of radiant heat impact.

Lots 1 – 6 are separated from the western VHC 9.1 by a minimum of approximately 50m
including partial shielding offered by the future dwellings on Lots 8 -10. The likely risk of a fire
front approach from the west would therefore expose the buildings within Lots 1 – 6 to an
acceptable risk of radiant heat impact as they too are separated by >17.2m from the forest
hazard.




© 2021                                              20