Altair louvre windows by Breezway with Crimsafe mesh screens have been tested by the CSIRO to BAL-29 bushfire conditions, allowing their use without the need for bushfire shutters.
Building occupants can survive a bushfire if the windows are able to reduce the amount of radiant heat entering the building from the fire, and also remain intact to prevent burning embers from coming in and causing a fire inside.
The Australian Standard governing building windows in bushfire prone areas of Australia (AS3959-2009) aims to ensure that the glass in the window doesn’t fail; even if it does, embers are still kept out by screens or shutters. Windows can comply with specific minimum characteristics (glass type, screen type etc.) for each Bushfire Attack Level specified in the Standard, or can undergo testing to prove their ability to withstand the expected bushfire conditions.
The Standard governing conditions up to Bushfire Attack Level 19 (BAL-19) requires Altair louvre windows to have their 6mm thick glass blades toughened and a woven metal mesh screen fitted to the outside of the window. This is an acceptable solution to the majority of Breezway customers.
Above BAL-19 though, because the Altair louvre clips that hold the blade in place are plastic and not metal, the Standard only allows two options: Cover the entire window with bushfire shutters, or pass physical testing to BAL-29, BAL-40 or BAL-FZ conditions.
With bushfire shutters not popular with the majority of their customers, Breezway submitted an Altair louvre window to the CSIRO in Sydney for testing to BAL-29 bushfire conditions early in 2013.
The testing involved installing a Breezway Easyscreen Altair louvre window into a section of moveable brick wall with multiple sensors positioned on the inside and outside of the window. The test window had both fixed windows and Altair louvres with Crimsafe woven metal mesh screens fixed to the outside of the louvre bays.
A gas furnace was used to heat a thick steel plate until it was red-hot, at which point the test was ready to commence. Small ‘cribs’ were positioned to the outside of the window to simulate burning debris. The cribs were set alight and the window exposed to the heat radiating from the red-hot steel plate.
Over the course of 30 minutes, the window was moved progressively further from the red-hot steel plate to simulate the passing of the fire front. Throughout the entire test, sensors checked the amount of radiant heat that the window was exposed to and how much the radiant heat was reduced by as it passed through the window.
Once the window was no longer exposed to the radiant heat from the steel plate, the window was carefully examined for any failure in the glass, screens or operating mechanisms and a flame was passed over all parts of the window to ensure it could not be set alight.
Having successfully passed the BAL-29 bushfire test, the Breezway Easyscreen window system with Crimsafe screens can be used in buildings with BAL-29 bushfire ratings without the need for bushfire shutters.