Can be timber with an inherent resistance to fire or fire retardant treated. 1943 national building code. Bush Fire | Bush Fire Resistant Timber | Bush Fire Rated Timber. Building codes recognize its superior performance by allowing larger sizes for buildings of this type. With the increase in frequency of bush fires and expansion of homes and other buildings into rural Australia, fire protection has never been more important. Heavy timber construction is also recognized in fire insurance rating schedules through lower rates. Joinery Timber (window and doors only) - Timber with density of 650 kg/m or greater, are timbers density at 12 percent moisture content. masonry walls shall have a fire-resistance rating of not less than three hours; And other structural members of steel or reinforced concrete, if used in lieu of timber construction, shall have a fire resistance rating of not less than one hour. Although the temperature at the char layer may be 300°C, the temperature of the inner core is considerably lower. Fire resistance of timber. This charred layer is the key to timber’s fire resistance, acting as an insulator that protects the inner core. This is the reason why time is required to build up sufficient heat so as to cause a flame in timber. They are solid, dense hardwoods that performed well in extensive fire testing Both fire-retardant (FR) treated timbers and specific species can be used in many external applications. BAL29 - Bushfire resisting timber. In order to make timber more fire resistant, the surfaces of timber are sometimes coated with certain chemicals such as ammonium phosphate and sulphate, borax and … But timber used in heavy sections may attain a high degree of fire-resistance because timber is a very bad conductor of heat. Suitable timbers are listed in AS 3959 Table E2. The excellent fire resistance of heavy timber framing has been demonstrated in many building fires over the years. Large timber members (sawn timber or glulam), can be naturally fire resistant thanks to the unique charring properties of the wood. The use of timber components in the loading structure in a building relies on fire engineering design to ensure that the building can retain its structural integrity for sufficient time either for building occupants to be evacuated, or for the fire to be extinguished.