The fire hazard of houses in bushland settings

The aim of the thesis was to examine trends in the pattern of house survival during a bushfire by analysing data from 450 houses affected by the bushfire of 16 February 1983 at Mount Macedon, Victoria. The possible effects on house survival of fire intensity, house design and construction materials, garden and bushland vegetation, topography, the proximity of fuels and other buildings, and the fire-fighting activities of residents and others, were evaluated. Literature concerning plant flammability was reviewed in terms of the "physical" and "chemical characteristics of live foliage. Flammability was found to decrease with increasing moisture and mineral content, with decreasing extractive content, and with decreases in the product of sample density, specific heat, and thickness. The influence on house survival of garden plants was, however, considered to depend on more than just foliage flammability: other factors, such as the degree of maintenance of the garden complex, might also be important. A logit model fitted to the house survival data established a relationship between the probability of house survival and the following variables:- fire intensity, attendance during a fire by householders and others, wall material, roof material and pitch, the proximity of flammable materials (such as heaps of fire-wood), and the height of garden vegetation. Fire intensity was considered to be the most important determinant of house survival, and fuel reduction was considered to be the major priority for the protection of houses against bushfires. The results of the survey suggested that able-bodied residents who are threatened by a bushfire should remain in their houses rather than flee in the hope of escaping the fire. Widespread adoption of this strategy may result in fewer deaths and a marked reduction in the loss of houses. Provision should, however, be made to evacuate - at least temporarily - disabled or infirm persons and the residents of houses surrounded by exceptionally high fuel loads