Many areas of Australia are subject to summer bushfires which cause loss of life, livestock, homes, farm buildings and infrastructure, and cost the country millions of dollars every year.
In Victoria in 2009, what became known as the Black Saturday bush fires, prompted the development of Australian Standard 3959-2009 (Construction of Buildings in Bushfire Prone Areas) which gives people who are building, re-building, retrofitting or renovating their homes, a clear direction on how to better protect their homes against bushfires.
There are four ways that a bushfire can destroy a home
Ember Attack – Embers are carried by strong, hot winds, many kilometres ahead of the fire front, and can enter a home through gaps as small as 1.8mm, igniting flammable materials, particularly leaf litter.
Radiant Heat – The intense heat from a close proximity bushfire dries out vegetation ahead of the fire, cracks and breaks windows, and melts and distorts plastic, again allowing gaps for ember ingress.
Direct Flame Contact – The fire actually touches the building and sets it alight.
Flame Driven Wind – During a bushfire, winds far in excess of normal are generated by the fire itself and can cause trees to fall on buildings, break windows, and loosen roof tiles (allowing embers to enter the roof space).
Ember attacks cause 80% of home loss during a bushfire, so anything that can be done to stop ember ingress, is going to be very effective in reducing the risk to your home. AS3959-2009 specifies the use of a corrosion resistant steel mesh with an aperture of less than 2mm. This can be used to protect windows, skylights, doors, decks, patios, evaporative cooling units, gable and roof vents, gutters, eaves and downpipes. A radiant heat bushfire mesh not only prevents ember ingress, but also reduces the intensity of radiant flux by approximately 50%.
Ember Attack Vs Radiant Heat- this is a great video. Jack Cohen, Fire Sciences Researcher, Fire Sciences Lab.
At Stainless Steel Wire & Mesh we have several stainless steel woven meshes that meet the AS3959 specification. These can be found on our website- Bushfire Mesh along with data sheets like the one below.
AS3959 specifies six bushfire risk categories. The BAL (Bushfire Attack Level) system is based on the potential danger of the site and construction materials, which considers the Fire Danger Index (FDI), vegetation type, distance of the site from vegetation, and the slope of the ground under the vegetation. Further information can be found on our website- Bushfire Mesh- More Information.
The Victorian Building Authority website has very useful information, including “A Guide to Retrofit Your Home for Better Protection from a Bushfire”.
State and Territory Bushfire Resources
VIC – Country Fire Authority
NSW – Rural Fire Service
QLD – Fire & Emergency Services
WA – Dept of Fire & Emergency Services
TAS – Tasmania Fire Service
SA – Country Fire Service
ACT – Rural Fire Service
NT – Fire and Rescue Service