Amended Compiled Approved Plans for OPW20-0145 04 · OPW20/0145.04

                                                                                                                         Noosa Civic | Page 11




                                                                    Figure 6

                               4.1.1. Direct Flame Contact
                               Direct flame attack refers to flame contact from the main fire front, the flame that engulfs burning
                               vegetation is the same flame that contacts the building. It is estimated that only 10 to 20 percent of
                               buildings lost to bushfire occur as a direct result of flame attack.

                               4.1.2. Ember Attack
                               CSIRO research has shown that ember attack is the cause of up to 80% of house loss in Australia.
                               The convective forces of bushfire raise burning embers into the atmosphere on prevailing winds and
                               deposit them to the ground ahead of the fire front. Typically, ember attack occurs approximately 30
                               minutes prior to the arrival of the fire front and continues during the impact of the fire front and for
                               several hours afterwards.

                               Building loss via ember attack relates largely to the vulnerabilities and peculiarities of each building,
                               its distance from the classifiable vegetation and whether someone is present to actively defend the
                               building.

                               4.1.3. Radiant Heat
                               Measured in kilowatts per m2, radiant heat is the heat energy released from the fire front which
                               radiates to the surrounding environment, deteriorating rapidly over distance. In terms of impacts on
                               buildings, radiant heat can pre-heat materials making them more susceptible to ignition. Radiant heat
                               can also damage building materials such as window glazing, allowing openings into a building
                               through which embers may enter.

                               4.1.4. Fire Driven Wind
                               The convective forces of a bushfire typically result in strong fire-driven winds, which can lead to
                               building damage. The typical effects of fire driven wind include conveyance of embers, damage from
                               branches and debris hitting the building, as well as direct damage to vulnerable building components,
                               such as lifting roofs and the breakage of windows.




                                                                                         Bushfire Planning Specialists | qldbushfireplanning.com.au
Document Set ID: 21426255
Version: 1, Version Date: 24/03/2021