Attachment 4 - Response to Further Advice Rob Friend and Associates

[15]


– Moist to dry eucalypt open forest on coastal lowlands and ranges, an downslope
characteristic of 8 degrees and a surface fuel load of 17.2t/ha and a total fuel load of
24.2t/ha the calculations is provided below in Table 3.

Table 3- Noosa Springs - Minimum Distance Calculator - AS3959-2018 (Method 2)
(Calculated October 9, 2020, 4:49 pm (MDc v.4.8)

    Inputs                            Outputs
    Fire Danger Index   48            Rate of spread                1.75 km/h
    Vegetation          Forest        Flame length                  14.28 m
    classification
    Surface fuel load   17.5 t/ha     Flame angle                   54 °, 64 °, 72 °, 76 °, 78 ° &
                                                                    83 °
    Overall fuel load   24.2 t/ha     Elevation of receiver         5.57 m, 6.14 m, 6.39 m,
                                                                    6.36 m, 6.31 m & 5.47 m
    Vegetation height   n/a           Fire intensity                21,888 kW/m
    Effective slope     8°            Transmissivity                0.872, 0.854, 0.828, 0.803,
                                                                    0.79 & 0.728
    Site slope          1°            Viewfactor                    0.599, 0.4456, 0.3007,
                                                                    0.2045, 0.1663 & 0.0451
    Flame width         100 m         Minimum distance to <                     11.7 m
                                      40 kW/m²
    Windspeed           n/a           Minimum distance to <                     15.7 m
                                      29 kW/m²
    Heat of             18,600        Minimum distance to <                       23 m
    combustion          kJ/kg         19 kW/m²
    Flame               1,090 K       Minimum distance to <                     32.4 m
    temperature                       12.5 kW/m²
                                      Minimum distance to <                     38.4 m
                                      10 kW/m²
     Rate of Spread - Mcarthur, 1973 & Noble et al., 1980
     Flame length - NSW Rural Fire Service, 2001 & Noble et al., 1980
     Elevation of receiver - Douglas & Tan, 2005
     Flame angle - Douglas & Tan, 2005
     Radiant heat flux - Drysdale, 1999, Sullivan et al., 2003, Douglas & Tan, 2005

The setback distance required to achieve a radiant heat flux of less than 29kW/m2 is 15.7m
from the potentially hazardous vegetation to the north. Figure 4 below designates the
setback edge of hazardous vegetation where the distance to the proposed building is 21.9m
from the north-eastern most corner, and 24.4m from the north-western most corner. This will
achieve a Radiant Heat Flux within 19-29kW/m2 which is within the sates acceptable level of
risk. Compliance with AS3959-2018 for a Class 3 Structure will be required.




RFA17-040 - Bushfire Hazard Assessment & Mitigation Plan | 61 Noosa Springs Dr. Noosa Heads 30 April 2022

                                 Rob Friend & Associates Pty Ltd