THE Bushfire Attack Level (BAL) of a building site is determined by using Australian standard AS3959. The BAL rating has implications for both the design of a building and the specification of materials. A new BAL calculator developed by WoodSolutions is based on information provided in AS3959 and gives home owners, architects, building designers, developers and others a convenient way of estimating the BAL without having to manually look up tables. A calculator gives a quick BAL rating and then shows how changing variables – such as the building location on the site – affects the BAL. The Bushfire Attack Level of any location on a building site depends on factors including the site slope, the distance from vegetation and the type of vegetation. Australian standard AS3959 provides information and methodology to calculate the BAL of a home and specifies the construction and/ or retrofi tting requirements. Variables such as the site slope can be entered accurately, not to the nearest 5 deg., and then changed so that you can immediately see the effect on the BAL. β€œThe BAL calculator will enable home builders, architects and designers to see how different placements or orientations of a home on a site can change the BAL,” FWPA national manager codes and standards Boris Iskra said. However, Mr Iskra pointed out that the WoodSolutions BAL calculator, while shown to be very accurate in testing, should be used as a preliminary design guide with final BAL calculations confirmed with the Australian standard. The WoodSolutions BAL calculator is available online <a href=”http://www.woodsolutions.com.au/Articles/Resources/BAL-Bushfire-Calculator-V1″ target=”_blank”>here</a>. Further information is available from the website www.woodsolutions.com.au which has timber species data, technical design guides and other free downloads created to inform architects, engineers and other design and building professionals. (Timber and Forestry eNews Issue 323, June 23 2014)