Compiled Plans & Documents OPW18-0342 02

                                                                        Bushfire Emergency Provisions
                                    Residential Aged Care Facility – 6 Grasstree Court, Sunrise Beach

     •    Radiant heat flux

     •    Fire-driven wind

     •    Smoke

During the progression of a bushfire event, these methods interact either exclusively or in concert. It
is estimated that approximately 80 to 90 per cent of buildings located within 100m of the bushland
interface are lost to bushfire, hence the relevance of statutory provisions and recommendations
implemented across Australia which respond to various types of buildings within 100m of adjacent
classifiable vegetation.




                                                Fire Front
  •Increasing wind impact                        Impact                   •Continued ember
                                                                           attack
  •Developing ember
   attack                             •Maximum wind impact                •Continued flame and
  •Ignition of spot fires             •Maximum ember attack                burning of larger/denser
                                      •Maximum radiant heat                materials
                                       attack                             •Decreasing radiant heat
                                      •Possible flame attack
                                      •Smoke
                                                                                     Post Fire
          Pre Fire Front
                                                                                      Front



             30 Minutes               5-10 minutes (approx.)                    1-4+ hours

Figure 2 - The typical phases of bushfire attack

Direct Flame Contact
Direct flame attack refers to flame contact from the main fire front, where the flame which engulfs
burning vegetation is one and the same as that which assumes contact with the building. It is
estimated that only 10 to 20 per cent of buildings lost to bushfire occur as a direct result of flame
attack.

Ember and Firebrand Attack
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, thus it is the longest lasting impact of bushfire attack. Firebrands occur
in a very similar manner but relate to larger items of debris that may still be carried by the wind when
alight, such as candle and ribbon barks.

In essence, building loss via ember attack relates largely to the vulnerabilities and peculiarities of
each building, its distance from the classifiable vegetation and whether an occupant (or the like) is
present to actively defend it. It is estimated by the CSIRO that approximately 80 to 90 per cent of
buildings lost by bushfire are lost as a result of ember attack either in isolation or in combination with
radiant heat impact.



Status: Provisions                                                                           December 2018
Project No.: 18-030                                                                                Page 8