Bushfire: Retrofitting Rural and Urban Fringe Structures—Implications of Current Engineering Data

Abstract

Since the 2009 Black Saturday bushfires in which 173 lives were lost, two-thirds of whom died in their homes, the question of what a home prepared for bushfire looks like has been repeatedly raised. The 2019/2020 fires saw us not much further advanced. This paper seeks to consolidate what is known about bushfire behavior, its influence upon structures, and, through this data, infer improved standards of practice for retrofitting rural and urban fringe homes. In particular, the prevention of ember and smoke incursion: the data suggesting the prior as the main mechanism of home destruction; the latter as high risk to sheltering occupant health. The article is framed around a comprehensive literature review, and the author’s own experiences and observations from fire impacted structures in Victoria’s northeast. The article’s import lies in demonstrating how embers and smoke may enter homes otherwise seen to be appropriately sealed prior to the fire’s approach. Included in the findings are developed hypotheses based on thermal expansion, pressure differentials and backdraft; offering defined paths towards future research. In addition, the work provides practical advice towards mitigating the identified issues using retrofit practices based upon the author’s practical experience as a tradesperson and building designer.

Special Issue “Environmental Technology Applications in the Retrofitting of Residential Buildings”

“…The eleventh paper, "Bushfire: retrofitting rural and urban fringe structures", Ref. [12] reviews extant research on bushfire behavior and its impact on residential structures. As a consequence of global warming, Australia and other parts of the world increasingly suffer from the devastation of bushfires.…”

Proceedings of the 27th Conference on Computer Aided Architectural Design Research in Asia (CAADRIA) [Volume 2]

“…Research into the cause of bushfire destruction of homes has demonstrated that fire damage is magnified by the proximity of buildings and secondary structures, whereby fires, through ember attack, radiant heat or flame, can travel from one structure to another (Blanchi and Leonard 2005). Given the complexities that relate to property loss associated with bushfires, few studies offer any clear statistical relationship between the inter-structure proximity and loss (Costin 2021) while greater research attention has focused on the proximity of a structure and bushland. Roberts et al (2021) modelled the effects of embers on property loss.…”