Bushfire Hazard Assessment & Management Plan v1 - 9A Jirrima Cres, Cooroibah

Bushfire Hazard Assessment & Management Plan v1                                                NCES REF: J000706
Lot 101 on SP168341 – 9a Jirrima Cres, Cooroibah



                  society will not accept this risk and measures are to be put in place to reduce
                  risks to at least a tolerable level.
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

4.2       Risk from Identified Hazardous Vegetation
The proposed Lot 1 building envelope has been allocated a 14m cleared asset protection zone
to the VHC 22.1 occurring within the site.
The bushfire risk acting on the proposed building envelope, in the absence of additional
mitigation measures being implemented, is detailed in Table 2. The degree of separation
offered to the adjoining vegetation is the primary driver of the assigned level of risk.
                                     Table 2 - Risk Assessment (Lot 1)
 Direction & Slope                 North 1º              South 1º              East 1º              West 1º

 Distance to
                                        14m                   14m                14m                  14m
 hazardous vegetation

 VHC’s                                  22.1                  22.1               22.1                 22.1

 Attack Mechanism

 Smoke*                        Not assessed          Not assessed          Not assessed        Not assessed

 Ember                         Likely -              Likely -              Likely -            Likely -
                               Intolerable           Intolerable           Intolerable         Intolerable

 Radiant Heat**                Likely                Likely                Likely              Likely
                               Intolerable           Intolerable           Intolerable         Intolerable
                               >1kW/m**              >1kW/m**              >1kW/m**            >1kW/m**


 Flame***                      Likely -              Likely -              Likely -            Likely -
                               Intolerable           Intolerable           Intolerable         Intolerable




* Risk of smoke impact has not been assessed. Smoke can travel long distances and exhibit a variety of densities
and composition. It is therefore not readily practicable to determine the separation distances needed to attain the
various risk classes. Furthermore, individuals will react differently to smoke impacts whereas individuals will
generally exhibit similar reactions to direct flame and radiant heat.
**<1kW/m² radiant heat exposure is considered the upper limit of tolerable indefinite radiant heat exposure to
humans (QFES 2019).
*** Assets located within 1.5 x the modelled flame length from the Flamesol output are assigned an Intolerable
Risk.
Assets located within >1.5 - <3 x the modelled flame length from the Flamesol output are assigned a Tolerable
Risk.
Assets located >3 x the modelled flame length from the Flamesol output are assigned an Acceptable Risk.

Table 2 identifies that the building envelope located within Lot 1 is exposed to a Likely
Intolerable risk of ember, radiant heat, and direct flame impact in the absence of additional
mitigation measures being implemented. Post development it is anticipated that the risk will
be reduced to at least a tolerable risk via implementation of the bushfire planning mitigation



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