The threat of bushfire is a harsh reality living in Australia. Our hot, dry climate means we can’t take anything for granted and a bush or grass fire can whip up in no time at all. Even homes not directly in the path of a bushfire are at risk of flying embers.
Doing all we can to protect our homes if living in a bushfire zone makes total sense. But did you also know that your external doors must meet Australian Standards?
The Standard, AS3959, specifies requirements for the construction of buildings in bushfire-prone areas to improve their resistance to bushfire attack from burning embers, radiant heat or flames generated by a bushfire.
Understanding the Bushfire Attack Level (BAL) of a home site, whether a new construction or a renovated existing home, is the first step to take.
BAL levels are based on the Fire Danger Index (air temperature, relative humidity, wind speed and drought impacts), the surrounding vegetation and proximity to it, the slope of the land and slope direction.
The six BALs are:
BAL-LOW: no special construction requirements required as there is a very low risk of bushfire attack.
BAL-12.5: principally concerned with ember attack and radiant heat in wind conditions up to 12.5 Kw/m2 and where the site is less than 100m from the source.
BAL–19: protection from ember attack and radiant heat but at an increased level to a maximum radiant heat flux of up to 19 kW/m2.
BAL–29: an increasing level of ember attack together with an increasing heat flux than BAL 19, but not having heat flux greater than 29 kW/m2.
BAL–40: increased load of ember and burning debris ignited by wind-borne embers; together with an increasing heat flux, but not greater than 40 kW/m2, with the likelihood of exposure to bushfire flames.
BAL–FZ: the top most exposure and has a direct exposure risk to flames from the fire front with ember attack and a heat flux greater than 40 kW/m2.
Each state and territory have slight differences in how BALs are assessed, but there are generally two ways of doing it: using Local Government predicted BALs or fire authority data, or using an accredited assessor to do an individual site inspection.
You know your BAL. What’s next?
Visit the Hume Doors website! Designed with safety in mind while not compromising on style, we offer an extensive range of doors designed and manufactured to meet the regulatory requirements for building in designated bushfire zones.
We have a comprehensive range of doors that meet BAL12.5, BAL19 and BAL29 criteria as specified in AS3959. Select from either tempered hardboard or veneer finished solicore doors with 6mm tempered safety glass.
Australian Standard 3959-2009 Construction of Buildings in Bush Fire Prone Areas (AS3959-2009) contains the construction requirements for each BAL. A copy can be obtained from Australian Standards, your local council or try a local library.
This handy guide from the Windows and Doors Industry Council contains a comprehensive explanation of how to design and build with timber doors and windows in bushfire-prone areas. Give us a call if you’ve got any questions.