If your home is in Glenbrook, Blaxland, Springwood, Winmalee, Mulgoa, Londonderry or the bush edge of Emu Heights and Cranebrook, it almost certainly has a bushfire attack level. The BAL rating in your planning certificate or bushfire report decides what windows, glass and screens you can fit. Here is the plain language version of what we see on jobs.
The ratings in one paragraph
BAL LOW means no special construction. BAL 12.5 and BAL 19 are the most common ratings in the lower Mountains and the Penrith bush edge: ember attack and some radiant heat. BAL 29 is higher radiant heat, common on streets backing directly onto national park. BAL 40 and BAL FZ (flame zone) are the top ratings, where direct flame contact is possible.
What changes at each level
From BAL 12.5 up, openable windows need screens with mesh of corrosion resistant steel, bronze or aluminium with holes no bigger than 2mm, and the frame has to be metal or bushfire resisting timber. That is why we recommend stainless steel mesh screens in aluminium frames on every opening of a BAL rated home: they satisfy the ember screen requirement and double as security. At BAL 29 the glass in the lower part of the window generally has to be toughened, and at BAL 40 the whole window system needs to be tested to AS1530.8.1. The CityView range we fabricate carries BAL40 ratings on most systems and the KlassicView and ClimateGuard ranges carry BAL29 on their tested configurations.
What we do at the measure
We ask for the BAL report or the rating on the planning certificate, then match each opening: screen mesh, frame, glass thickness and whether the system needs a tested rating. Winmalee rebuilds after 2013 taught the whole district how strict this can be, and it is far cheaper to get it right at the quote than to fail a certifier inspection.
Do not forget the flyscreens
A standard fibreglass flyscreen does not meet the ember screen requirement. On a BAL rated home every flyscreen should be metal mesh in a metal frame. We fit them at the same visit as the windows and security screens. Book a free measure and bring the bushfire report.