As of May 2010 The Australian Building Codes Board (ABCB) endorsed the final draft version of the Australian Standards 3959 - Building in Bushfire Prone Areas code, which is now referenced by the Building Code of Australia.
There is now a specified methodology for the determination of building's construction requirements.
These determining factors are:
• Whether the building is in a designated bushfire prone area.
• The bushfire attack level (BAL) of the building based upon the site classification
• The selection of the appropriate construction solutions for the determined BAL rating.
The levels are based on radiant heat flux exposure and range from 'Low' to 'Flame Zone' These are now recognized as the six levels of bushfire attack.
Because of Australia's ongoing history of bushfire prevalence many homes will come under periodic threat from serious bushfire danger. Acol Skylights is mindful of this threat and for this reason we have released a range of roof windows and skylights which comply with the new ABCB code.
HandiLite Skylight’s Skylight and Roof Window range can be fabricated to be fully compliant with the BAL rating requirement of 40 or less.
All HandiLite Skylight and Roof Window exterior flashings are manufactured using the same material from which the roof in fabricated, being either .55mm Zincalume or .55mm Colorbond Steel. In addition our window frames are made from powdercoated aluminium rather than timber. The Skylight or Window can be glazed with 6mm toughened glass as a minimum. This ensures that all exterior componentry of the window is fabricated with 100% non-combustible material. The exterior flashings are also fabricated with no open gaps or seams in the trays; making the window fully resistant to ember attack when correctly installed. (Installation must be performed using ‘Ember Guard’ to seal all openings and seams, as required with all roofing installations)
In addition to this, windows can be furnished with aluminum or stainless steel insect screens rather that traditional nylon screens, providing a material impervious to ember attack even when the windows are in open position.
Bal - 12.5 Ember attack 12.5 kW/M2
Bal - Low There is insufficient risk to warrant specific construction requirements <12.5 kW/m2
Bal - 19 Increasing levels of ember attack and burning debris ignited by windborne embers together with increasing heat
flux between 12.5 and 19 kW/m2
Bal - 29 Increasing levels of ember attack and burning debris ignited by windborne embers together with increasing heat
flux between 19 and 29 kW/m2
Bal - 40 Increasing levels of ember attack and burning debris ignited by windborne embers together with increasing heat
flux and increased likelihood of flame exposure to 40 kw/m2
Bal - Flame Zone Direct exposure to flames from fire front in addition to heat flux and ember attack > 40 kW/m2