Building and Occupant Protection
The 2003 Canberra bushfires were noted for very high levels of house loss deep into suburban areas. Fire jumping from house to house was a major issue.
Project leader Justin Leonard of CSIRO Sustainable Ecosystems set out to look at what aspects of house construction contributed to such losses. He also looked at the safety of wooden power poles – many of which caught fire and fell, blocking roads, in the Canberra fires – as well as the critical issue of surviving in a car if caught by fire on the road.
In an effort to understand the role of critical elements in and around the home, the research team conducted a series of experiments over several years. At the New South Wales Hot Fire Facility at Mogo, the team subjected typical home fences, decks, windows, water tanks and fences to flames typical of bushfires.
The tests found, for example, that metal fences survived the best. Hardwood fences, though they would burn, acted as a barrier to radiant heat, helping to protect a home. Softwood fences such as treated pine had the worst performance – as well as burning, the resulting ash, containing arsenic, was a potential health issue. Steel water tanks proved the most reliable, though their plastic liners needed replacing after a serious fire.
As a result of this research, several companies have developed highly modified steel water tanks and water delivery systems that are commercially available for use in bushfire areas.
“Ideally this research willalso help provide advice to property owners on the level of risk to their homes and businesses and help develop education programs for local communities,”said Leonard.
Fire agencies have long advised against being caught on the road in a bushfire, but there was little detailed research on how bushfires affect cars and how best to survive if you are in a car and confronted by a bushfire. In an experiment that placed seven common vehicles under the bushfire simulator, this research identified key issues that influenced survivability including the orientation of the car to the fire, the relative temperatures in different areas of the car, the adverse influence of an air conditioner or recirculating air systems, and the toxic chemicals produced inside a car subject to intense heat.
The project’s postgraduate student, Julian Black of RMIT University, worked on developing a Geographical Information System toolto allow for various residential scenarios, such as different types of windows, doors, or walls,to be developed and visualised, based on building and planning requirements. This tool could assist in developing building and planning regulations that enable residential areas to perform better under bushfire attack.
Overall, this project has led to significant national policy changes as well as the development of new products, especially windows, and has fed through in the update of Australian Standard 3959 – Construction of buildings in bushfire-prone areas.
After the 2009 bushfires in Victoria researchers from this project examined more than 1300 properties in the fire areas. They documented in detail the extent of damage to properties, made conclusions on why some houses burnt and others did not, and compared the merits of different types of construction materials. This examination combined with other Bushfire CRC work as evidence before the 2009 Victorian Bushfires Royal Commission.