Altair Louvre Windows by Breezway with Crimsafe mesh screens are the only louvre windows that have been tested by the CSIRO to BAL-29 bushfire conditions, allowing them to be used without the need for bushfire shutters.
For the occupants of a building to stand a good chance of surviving a bushfire, the windows of a building must reduce the amount of radiant heat that enters the building from the fire front and must remain intact to prevent burning embers from entering the building and setting the interior alight. The Australian Standard that governs the windows used in buildings in bushfire prone areas of Australia (AS3959-2009) aims to ensure that the glass in the window doesn’t fail, but if it does, that 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.
Up to Bushfire Attack Level 19 (BAL-19) the Standard requires Altair Louvre Windows to have their 6mm thick glass blades toughened and to have 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: Either:
1. cover the entire window with bushfire shutters, or
2. pass physical testing to BAL-29, BAL-40 or BAL-FZ conditions.
With bushfire shutters not popular with the majority of our 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 was then 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 failures 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.
The Breezway Easyscreen Window System with Crimsafe Screens successfully passed the BAL-29 bushfire test and can therefore be used in buildings with BAL-29 bushfire ratings without the need for bushfire shutters.
Other woven metal mesh screens are currently being assessed by the CSIRO for equivalency to the Crimsafe woven metal mesh screens used in the physical test.