Bushfire Management Report

                         Ecological Natural Area Management



7.4       Results of bushfire attack modelling
The results of the bushfire attack modelling are tabulated below.
Table 6: Assessed Bushfire Attack Levels (BAL) for the modelled bushfire attacks
                                                                    Modelled bushfire attack
Modelled bushfire parameter                       East bushfire attack                      North bushfire attack
Separation from the hazard                              14 m                                       19 m
Vegetation                                       Woodland                                   Woodland
Modelled surface fuel load                              15 t/ha                                    15 t/ha
Modelled total fuel load                                25 t/ha                                    25 t/ha
Vegetation slope (degrees)                             9.6 0                                    10.5 0
Site slope (degrees)                                   9.6 0                                      9.2 0
Fire run                                               160 m run                                 300 m run
Proportion of QSS ROS                                 0.60                                      0.70
QSS ROS                                               1.40 km/h                                 1.49 km/h
Modelled rate of spread                               0.84 km/h                                 1.04 km/h
Flame width                                            100 m                                     100 m
Radiant heat                                        18.75 kW/m2                                15.57 kW/m 2
Modelled fire line intensity                        10850 kW/m                                 13433 kW/m
Modelled flame length                                 8.46 m                                    9.76 m
Level of construction (BAL)                        BAL 19                                     BAL 19

From the above tabulation, the worst case Bushfire Attack Level is BAL 19
See Appendix 2 for a detailed software reports from which the above table was generated.


7.5       Bushfire Attack Levels for each building elevation
Australian Standard AS3959: Construction of buildings in bushfire-prone areas specifies that the
building elevation opposite the assessed bushfire attack direction can be reduced one BAL level due
to shielding by the building but, as more than one attack direction is assessed as BAL 19, shielding is
not available so the Bushfire Attack Levels for each of the buildings elevations are:
      •    BAL 19 for all building elevations




Bushfire Risk Assessment and Management Plan for a house at 26 Little Springs Lane, Lake MacDonald            February 2021

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