Approved Plans MCU22-0147

Bushfire) is considered a suitable benchmark that would assist in reducing the risk to the development to
an acceptable level (in combination with other mitigation measures detailed within this report).
Assessment Benchmark 4 requires that development supports, and does not hinder, disaster
management response or recovery capacity or capabilities. 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 (29kW/m2) 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 habitable 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 29kW/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 development to assist in reducing the overall
bushfire risk to an acceptable level and achieve compliance with Assessment Benchmark 4 of the SPP.

Quantitative modelling using Flamesol bushfire modelling software has been undertaken to identify the
setback requirements to achieve the recommended <29kW/m² radiant heat flux separation. The input
data used, and the calculated required cleared setbacks are presented in Table 2 below with the full
Flamesol transcript provided as Appendix B.

Table 2 – Radiant Heat Flux Minimum Setbacks to secure <29kW/m²
 DIRECTION SLOPE                        FLAME          VEGETATION   MIMINMUM SETBACK     SETBACK CURRENTLY
                                        WIDTH          HAZARD       REQUIREMENT          PROVIDED TO THE
                                                       CLASS                             COTTAGE
 North         4.5 degrees              100            VHC 8.1      29.1m                ~70m
 West to       1 degree (upslope/across 100            VHC 8.1      25.3m                 60m
 south-west slope)

The cottage is provided with a minimum 70m setback to the adjoining VHC 8.1 hazardous vegetation
where it is located downslope and a minimum 60m setback to the adjoining VHC 8.1 hazardous vegetation
where it is located upslope or across slope. These setback distances far exceed the recommended
minimum 29kW/m2 radiant heat exposure. The minimum distance calculations presented within the
Flamesol modelling in Appendix B demonstrate that the cottage would be exposed to <10kW/m2 radiant
heat exposure. Although short-term accommodation is not listed as a vulnerable use under the SPP, the
setback distances provided are equivalent to the 10kW/m2 setback requirement prescribed within the
SPP Bushfire. Given the considerable amount of hazardous vegetation in the local landscape and the
likelihood of potential impact (as demonstrated in Section 4 above), the <10kW/m2 radiant heat exposure
to the cottage is a very positive result and will greatly assist in reducing the risk of bushfire impact to the
development to an acceptable level.



JULY 2022                     BUSHFIRE HAZARD ASSESSMENT & MANAGEMENT PLAN                             Page: 19
                                          296 KIDD ROAD, POMONA