Appendix A - Bushfire Hazard Assessment & Management Plan

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




3.3 Quantitative Modelling
Quantitative modelling of the potential bushfire conditions that may be experienced within the
VHC 22.1 Melaleuca open forest within the site has been undertaken to gain an appreciation
of the severity of risk acting on the site including exposure to direct flame contact and radiant
heat. An understanding of the latter is used to determine the dimensioning of asset protection
zones to satisfy the SPP requirements.
The models used comprise industry standard bushfire equations which have been built into
the FPAA endorsed FLAMESOL computer model. FLAMESOL allows numerous input
variables to be adjusted including fuel loads, fire danger index, site slope and distance to
vegetation. FLAMESOL uses the following algorithms:




                                                                                                    DRAFT NOT FOR SUBMISSION PURPOSES
    •    Rate of Spread – McArthur (1973) and Nobel et al. (1980)
    •    Flame Length – NSW Rural Fire Service (2001) and Nobel et al. (1980)
    •    Elevation of Receiver – Douglas and Tan (2005)
    •    Flame Angle – Douglas and Tan (2005)
    •    Radian Heat Flux – Drysdale (1999), Sullivan et al. (2003) and Douglas and Tan (2005)
The FLAMESOL Minimum Distance calculator has been used and comprises an AS
3959:2018 Method 2 (Appendix B) based calculator which populates standard bushfire
behaviour variables as well as the minimum distances required to achieve a range of different
radiant heat level exposures, including those which correspond with the range of Bushfire
Attack Levels (BAL’s) prescribed under AS 3959:2018 Construction of Buildings in Bushfire
Prone Areas.
Fuel load inputs have been drawn from Planning for Bushfire Resilient Communities (QFES
2019) based on the calculated potential fuel loads for VHC 22.1 (23.4 t/ha surface and near
surface fuels and 28.4 t/ha total fuels). 1º effective slope was adopted for the slope underlying
the VHC 22.1 Melaleuca Open Forest.
A FDI of 47 has been adopted for the site consistent with the assignment by QFES (Catalyst
2020) (refer Plate 9).




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