|
|
|
|
|
|
|
|
|
| CSIRO | SOLVE | Issue 7 | May 06 | |
|
|
|
ARTICLE
PROPERTY PROTECTION:
Fighting Fire With Steel By David Adams
New research on the role fences play in protecting houses against bushfire has quantified the obvious – steel fences are a better fire barrier. Researchers have been burning fences, ‘attacking’ them with embers and subjecting them to extreme bushfire conditions to demonstrate, scientifically, the building materials that best defend property against bushfires.
By comparison, fences constructed from both soft and hardwoods often burn down and, in worst cases, act as a bridge between the fire and adjacent property. The research has been a six-month study conducted by the Bushfire Cooperative Research Centre (CRC) and CSIRO. The work was funded by fencing manufacturer BlueScope Steel. Project leader Justin Leonard says the findings have quantified the role steel fencing can play in defending property against bushfire. “Building codes and virtually all planning guidelines in Australia haven’t actually addressed the issue of the risk that fences create,” says Mr Leonard, who heads the CRC’s research into property protection and urban interface performance. The Bushfire CRC brings together fire and land management authorities, academics and government organisations for the purpose of sharing knowledge and minimising bushfire risk. Mr Leonard says there has been a lack of formal knowledge and data on just how and why fences make a difference in property protection. The findings have been presented to town planning organisations in several states, and are expected to be integrated into building standards and planning guidelines for bushfire-prone areas. Kevin O’Loughlin, the Bushfire CRC’s chief executive, says the research adds to the increasing amount of knowledge being collated on the impact of bushfire in the urban/bush interface. “This project is an example of how targeted research can help fire and land agencies and the general community better understand how to reduce bushfire risk,” he says. “As more and more people move into bushland areas and the urban fringe, there is an expectation that fire agencies, local government and communities are better able to assess and manage the increased bushfire risk associated with this development. “This can also help individuals make better informed decisions when building structures on their properties.” The research findings are based on a series of live tests that were carried out on 1.3 kilometres of fencing at the NSW Rural Fire Service’s site at Mogo, just south of Batemans Bay on the NSW south coast, late last year. The objective was to measure how various fences made from wood and metal behaved under bushfire conditions and whether they added to, or reduced the fire risk for nearby structures. Steel fences are the most effective at withstanding the intense heat generated by a bushfire “The hardwood fences tended to resist the ember attack and would only ignite and burn when there was heavy fuel and radiant heat load,” Mr Leonard says. “It would sort of burn down in sympathy with other materials like vegetation, ground fuel or mulch or an adjacent shed or structure.” While, as expected, the metal deck fencing did not burn, Mr Leonard says the high level of radiant heat it could withstand without buckling was unexpected: “It surprisingly stood up to some very high-intensity flame and radiant heat.” He says the tests simulated the worst that a bushfire could deliver: “They imitated the build-up of radiant heat that occurs when a fire front approaches as well as scenarios in which fences were in direct contact with fire in the surrounding bush. The worst-case exposure simulated a nearby structural fire in which one side of the fence was immersed in flame for 30 minutes.” Mr Leonard says the metal fencing stood up to all tests, maintaining structural integrity even in the face of direct immersion in flame. The style of fence was found to make a significant difference during tests of wooden fences. Those with overlapping panels to create a solid fence performed significantly better than fencing with gaps between the palings, which offered almost no protection during flame attack. With steel fencing, the style of fence made little difference because most steel fences are constructed along similar principles. Jason Cruickshank, national market development manager at BlueScope Steel, which supplied steel fences for the tests, says the company was “very interested” to find out how its products performed under bushfire conditions. Although it was known, anecdotally, that steel performed well, the research now allows the company to describe the nature of this performance with a much higher level of credibility. APPLICATION Steel fences can withstand high flame intensity and radiant heat BENEFIT Superior bushfire protection for buildings and property than that offered by wooden fences For further information contact: |
 IN THIS ISSUE
|
| Home | About Us | eSubscribe | Links | |
|
|
||
|
|
|
Not surprisingly, the experiments found
that of the fences assessed, steel fences are
the most effective at withstanding the intense
heat generated by a bushfire and at providing an
effective barrier against a fire front. 
Back to main