Bushfire Hazard Assessment

Bushfire Hazard Assessment
14 Serenity Close, Noosa Heads



modelled inputs for potential fuel load (Map 7), maximum landscape slope (Map 8) and
fire weather severity/FFDI (Map 9), respectively.

PFI was calculated in accordance with Leonard et al. (2014a):

                                         𝑃𝑃𝐹𝐹𝐼𝐼 = 0.62 𝑊𝑊 2 𝐹𝐹𝐹𝐹𝐹𝐹𝐹𝐹𝑒𝑒 (0.069𝜃𝜃)     (Equation 1)

         Where: 𝑃𝑃𝑃𝑃𝑃𝑃 = Potential Fireline Intensity (kW/m);

                   𝑊𝑊 = Potential fuel load (tonnes/ha);

                   𝐹𝐹𝐹𝐹𝐹𝐹𝐹𝐹 = Fire weather severity/FFDI; and,

                   𝜃𝜃 = Maximum slope (degrees).

Resulting PFI was then classified into one of three (3) potential bushfire hazard classes, as
outlined in Table 1.

TABLE 1: POTENTIAL BUSHFIRE INTENSITY CLASSES (SOURCE: LEONARD ET AL. 2014).

  Potential Bushfire Intensity        Potential Fireline Intensity
  Very High                           40,000+ kW/m

  High                                20,000 – 40,000 kW/m

  Medium                              4,000 – 20,000 kW/m




6.2.3    RADIANT HEAT FLUX


Where modelling results indicated that the proposed development was located within a
bushfire prone area and/or potential impact buffer, radiant heat flux and associated
Bushfire Attack Level (BAL) was calculated according to the View Factor Method
described in AS 3959:2018 (Standards Australia 2018). Separation distances for achieving
the various BAL levels were calculated using the SPP Bushfire Asset Protection Zone
Width Calculator (Queensland Fire and Emergency Services 2019), including inputs based
on:

   ● Distance(s) between the closest edge of the proposed building and the edge of
        areas of potential fireline intensity, with radiant heat flux calculated consistent with
        the height of the adjacent vegetation, maximum flame angle and modelled flame
        lengths.
   ● Fuel loads derived from the post-development map of vegetation hazard classes
        and site-based survey (Map 7 and Appendix 2).
   ● Effective and site slope under the classified vegetation were calculated from the
        landscape slope map (Map 8).
   ● An FFDI of 48 based on the 5% AEP event as per Leonard et al. (2014) (Refer to Map
        9).
   ● Flame width based on maximum front width perpendicular to the development
        footprint.

Supplementary Method 2 input parameters and adopted values are listed in Table 2.

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