Approved Plans - MCU21/0221

           4.0        SETBACKS
           The site assessment undertaken above has concluded that the proposed dwelling is to be located within
           a High Potential Bushfire Intensity area (refer to Local Hazard Map presented as Figure 1). Therefore,
           sufficient setbacks from hazardous vegetation should be implemented to reduce the risk of possible
           uncontrolled wildfire events to the dwelling.
           There are no specific setback criteria for a Material Change of Use development application under the
           Noosa Plan Bushfire Hazard Overlay Code or the SPP Assessment Benchmarks. Assessment Benchmark 4
           of the State Planning Policy – state interest guidance material states: Development supports, and does
           not hinder, disaster management response or recovery capacity or capabilities. Where reconfiguring a lot
           creating lots of greater than 2000 square metres, to ensure emergency access and operational space for
           firefighters the subdivision layout results in lots that are sited so that they are separated from the closest
           edge to the adjacent medium, high or very high potential bushfire intensity area by a distance that
           achieves a radiant heat flux level of 29 kilowatt per square metre or less at:
           1. The building envelope, if identified at RaL stage, or
           2. Where a building envelope is not identified, at all the lot boundaries.
           Compliance with Assessment Benchmark 4 can be attained where proposed dwellings are sufficiently
           separated from the nearby forest hazard so that a radiant heat flux level at any point on the building does
           not exceed 29 kW/m². The setback must be maintained as a dedicated Asset Protection Zone which
           comprises only low threat vegetation, such as maintained lawns and cultivated gardens or are designed
           to ensure a potential available fuel load is maintained at less than 8 tonnes/hectare in aggregate and with
           a fuel structure that remains discontinuous.

           Whilst it is acknowledged that the application is not for a reconfiguration of a Lot development approval,
           it is considered that the 29kW/m2 minimum separation prescribed in Assessment Benchmark 4 is a
           suitable minimum setback to be applied to the proposed dwelling. The separation required to achieve
           <29kW/m2 radiant heat flux is equivalent to a BAL 29 construction standard under AS3959:2018.

           4.1        SETBACK CALCULATIONS
           Modelling has been undertaken to determine the setback distance required for the dwelling to achieve
           the recommended 29kW/m2 separation. The models used comprise industry standard bushfire equations
           using the FLAMESOL computer model. The FLAMESOL Minimum Distance calculator has been used and
           comprises an AS3959 Method 2 based calculator which can determine a suite of bushfire behaviour
           variables including the minimum distances required to achieve a range of different radiant heat level
           exposures. The quantitative modelling output has been used to identify the setback requirements to
           achieve the recommended <29 kW/m² radiant heat flux setback and achieve a BAL 29 construction
           standard under AS3959. The modelling output is shown in Plate 8 and summarised in Table 2.




           October 2021                            BUSHFIRE HAZARD ASSESSMENT                                    Page: 14
                                                   797 Ringtail Creek Road, Pomona
Document Set ID: 21731677
Version: 1, Version Date: 14/12/2021