How should future building structure and emergency response cope with bushfire attacks? (#8)
Bushfires are regular occurrences in the Australian landscape which can, under adverse weather conditions, give rise to losses of life, property, infrastructure, environmental and cultural values. Where property loss is involved, historical surveys of house losses have focussed on ember, radiant heat and flame contact as key bushfire attack mechanisms. Although often noted, little work has been done to quantify the impact of fire generated or fire enhanced wind and pyro-convective events on house loss and to improve construction practice within Australia. It is well known that strong winds are always associated with bushfire events. It is less well known, although increasingly shown through anecdotal evidence, that bushfires are not a passive companion of wind, but indeed they interact with winds and can together cause significant damages to exposed buildings and ecological structures. This paper presents an investigation of the role of wind-fire interactions with a focus on the ground level environment, i.e. the level of importance to the built environment. A literature review was conducted to collect information in regard to the mechanisms of property damage during bushfire events. The results of computer simulation are then presented to demonstrate the enhancement of wind by fires at the ground level and the possible consequences in terms of the increased wind loads on building structures. Furthermore, wind reversal or partial reversal was observed in the simulations and shall be discussed. Based on results of this study, it is recommended that the relevant standards for wind loading and construction in bushfire prone areas be reviewed. The author’s believe it is necessary to consider wind as an attack mechanism in bushfire events. The results of the study will also have implications on bushfire emergency management, design of emergency shelters, perception of danger, emergency evacuation and on risk assessment.