This bushfire season has been terrifying with over 2,000 homes destroyed in Australia. Questions are being asked about back-burning and other fire prevention methods. Another question worth asking is if the homes could have built in a way that was more fire-resistant.
The reality is newer homes are usually more fire-proof than older builders. Building regulations have changed over time and homes in bushfire-prone regions have certainly improved in terms of fire-resistance.
The National Construction Code sets standards for construction of buildings in fire-prone areas, that is areas that have been declared fire-prone by the state or territory.
Homes built on fire-prone land are required to be designed and constructed in a way that reduces the risk of ignition in the event of a bushfire. Flames, burning embers and radiant heat all pose a fire-risk and are taking into account in design. Various factors increase the fire-risk including the density of vegetation and the slope of the land and should be considered closely at the design stage.
Every element of construction is covered under the Code including walls, roofs, floors, windows, verandahs, vents, and water and gas pipes.
As an example, a high fire-prone area may require fire-resistant timbers to be used for framing and windows may need to contain toughened glass.
Building regulations are established by taking into account the net benefit – that is the cost of compliance versus the benefit to the community. Over-stringent building codes can be cost-prohibitive; not enough stringency could increase the risk of fire-damage, so the intention is to get the balance right.
The latest bushfires will lead to a post-fire analysis of the sufficiency of Codes and reforms may be suggested. The royal commission that followed the Black Saturday fires made recommendations for modifications to the National Construction Code including making protection from ember attack a performance requirement and addressing the design and construction of private (underground) bushfire emergency shelters.