HOUSES in lower bushfire danger areas should have greater protection against ember attacks under Victoria's new bushfire building code, according to the Black Saturday Royal Commission.
In a new report on building standards and bushfire bunkers, tabled in Parliament yesterday, the commission has recommended increased safeguards against bushfire embers in the construction of doors, windows and wall barriers.
It also called for national regulations on bushfire bunkers by the end of April. Earlier this month, Victoria put an interim bunker and shelter accreditation system in place until the national standards are introduced.
The commission has heard that in bushfires, most houses ignite and burn due to wind-borne embers that find the weakest links in the construction of a house.
''Unlike direct flame exposure and radiant heat, which are only expected at the highest bushfire attack levels, ember attack is a threat at all bushfire attack levels,'' the report stated.
Under post-Black Saturday building regulations, homes are categorised into one of six ''bushfire attack levels'', from low to extreme, based on risk factors including the fire danger index, the slope of land and vegetation.
The second interim report of the commission recommended Standards Australia increase ember protection standards by March 2010 and that unmanaged grasslands be included in vegetation types used to decide building standards. Currently, unmanaged grassland is not considered in an assessment of a bushfire attack level, except in Tasmania.
The commission also said the absence of minimum standards for bunker designs, given the widespread demand for and availability of the structures, was of ''grave concern''.
The report said the bushfire bunker standards should consider issues such as fire resistance, strength, resistance to winds, size and maximum time a structure can be occupied.
While the commission has heard from several witnesses who survived the February 7 blazes in bunkers or similar structures, seven people died in such refuges.
The report tells of a Humevale man who died in a purpose-built bunker, with police officers likening the structure to an oven, observing that it contained burning hot embers.
''While a well-designed and constructed bunker may provide a temporary place of refuge during the passage of the fire front, bunkers are not a panacea,'' the report warned. ''Misplaced reliance on a bunker can be life threatening.''
The Australian Building Codes Board has said it will release bushfire bunker standards before April 30 next year.
Premier John Brumby said he backed the commission's recommendation for national bunker regulations, saying the right design can ensure a high degree of safety.
''Tragically there were a number of lives lost, where people believed they would be safe in a bunker and they were horribly burned and lost their lives,'' he said.
The Premier said it was vital that people considering building a bunker or shelter are aware of the risks and the standards needed for the refuge to be a safer place of last resort.
Opposition bushfire spokesman Peter Ryan supported the creation of a national bushfire bunker standard, saying Victorians who want to build a bunker should have the security of an Australian standard as soon as possible.
''It is critically important that Victorians can adhere to national regulations on bushfire bunkers, knowing that what they build has undergone thorough scrutiny,'' he said.
The commission recommended the national bunker standard be adopted in Victoria by no later than May 2010.
