AS3959-2009 & Ember Guard Compliant Mesh

AS3959-2009 & Ember Guard Compliant Mesh

by | Aug 22, 2022 | Bushfire & Ember Guard

After the devastating Victorian “Black Saturday” bushfires in 2009, the Australian Standard for the construction of buildings in bushfire-prone areas was updated.  

The rules laid out in the new standard, AS3959–2009, are designed to reduce your home’s risk of ignition from a bushfire. 

The standard prescribes particular construction details for new buildings and homes that are constructed in areas with a BAL (bushfire attack level) of 12.5 or higher.  

While no measure can guarantee your home will survive a bushfire, these measures are designed to better equip your home to withstand the effects of bushfire.  

And although this standard only applies to new homes in bushfire zones, it can also be used to guide bushfire proofing measures for older homes or homes in a low bushfire risk area. 


About ember attack 

Many of the measures in AS3959–2009 are designed to protect your home from ember attack.  

Ember attack occurs when embers (smouldering or flaming windborne debris) fly ahead of the fire front, setting your home alight as they burn the vegetation and fuel around it or are sucked inside to start internal fires.  

As over 85% of fires that destroy homes during a bushfire are actually caused by ember attack, it’s clearly important to take measures that equip your home to better withstand this threat. 


What’s an ember guard? 

An ember guard is a cover that is inserted in or over an opening or cavity in your home in order to protect it from ember attack by preventing burning embers from gaining entry.  

Ember guards can be made from several different types of materials, including metal mesh manufactured from approved metals with a maximum aperture of 2mm.  

Blue Mountain Co’s 2mm steel gutter mesh is ember guard complaint, meaning it can be used as an ember guard in prescribed areas around your home, helping you meet the requirements outlined in AS3959–2009. 


Using ember guard compliant mesh  

Ember guard compliant mesh such as our 2mm steel mesh can be used in the following areas to fulfil the requirements from AS3959– 2009: 

  Roof ventilation openings (e.g. gable and roof vents)  Gaps greater than 3mm in sheet roofs at the fascia or wall line and at valleys, hips and ridges  Openings in vented roof lights, roof ventilators or vent pipes  Evaporative cooling units  Eaves ventilation openings greater than 3mm  Roof light glazing in roofs having a pitch of less than 18 degrees to the horizontal 
BAL 12.5  Required – see clause 5.6.1(c)  Required* – see clause 5.6.3(b)  Required – see clause 5.6.5(b)  Required* – see clause 5.6.5(f)  Required – see clause 5.6.6(c)  N/A 
BAL 19  Required – see clause 6.6.1(c)  Required* – see clause 6.6.3(b)  Required – see clause 6.6.5(b)  Required* – see clause 6.6.5(f)  Required – see clause 6.6.6(c)  N/A 
BAL 29  Required – see clause 7.6.1(c)   Required* – see clause 7.6.3(b)  Required – see clause 7.6.5(b)  Required* – see clause 7.6.5(f)  Required – see clause 7.6.6(f)  Required – see clause 7.6.5(e) 
BAL 40  Required – see clause 8.6.1(c)  Required* – see clause 8.6.3(b)  Required* – see clause 8.6.5(a, c)  N/A  Required – see clause 8.6.6(f)  Required – see clause 8.6.5(c) 
BAL FZ  Required – see clause 9.6.1(c)  N/A – gaps need to be sealed using other materials  N/A – gaps need to be sealed using other materials  N/A  N/A – gaps need to be sealed using other materials   N/A – roof lights must comply with other requirements – see clause 9.6.3(b) 


* Gaps can also be sealed using alternative materials or items – refer to the standard for more information  


For homes in BAL 12.5 to BAL 29, ember guard compliant mesh must be made from corrosion-resistant steel, bronze or aluminium.  

For homes in BAL 40 and BAL FZ, only corrosion-resistant steel or bronze mesh are compliant. 


Gutter guards & bushfire compliance 

The Australian Standard for the construction of buildings in a bushfire area doesn’t mandate the installation of gutter guards or gutter mesh on new homes.  

However, if you do install gutter mesh in a new home in any bushfire zone, AS3959–2009 stipulates that it must be made from non-combustible materials.

At Blue Mountain Co, we recommend you install ember guard compliant 2mm steel gutter mesh as a gutter guard if your home is in a bushfire-prone area. Because this mesh is non-combustible and small enough to keep embers out of your home, it should largely prevent leaves and other flammable debris from entering your gutters, providing added protection against the threat of ember attack. 


Defend Your Home 

No measure can guarantee that your home will be safe from the threat of bushfire or ember attack.  

But by using ember guards and following the standards laid out in AS3959–2009, you can give your home its best chance of survival.  



Disclaimer: Every effort has been made to ensure these guidelines are consistent with AS3959–2009. However, we cannot guarantee the accuracy of any of the information on this web pageAs such, we recommend that you refer to the Australian Standard yourself, or seek tailored advice from a qualified expert.

Blanchi & Leonard, Investigation of Bushfire Attack Mechanisms Resulting in House Loss in the ACT Bushfire 2003, 2005
Standards Australia, Construction of Buildings in Bushfire-Prone Areas, 2009