The 2009 Black Saturday bushfires really highlighted the need for good intrinsic protection against fires in the construction of Australian buildings, otherwise known as passive fire protection. In response to Black Saturday the Australian government introduced the BAL rating system, which sets out appropriate precautions at 6 bushfire risk levels.
The following is a brief guide to passive fire protection measures, based on BAL guidelines, that should be considered in the construction or retrofit of any building or property:
Floors – A concrete slab, fully enclosed by external walls, is probably the most fire retardant flooring solution. Concrete can also be used to enclose any existing sub floors. Pro Grind is one of many companies featured on Infolink that can offer advice on installing an eco friendly concrete flooring solution.
As an alternative, in less high risk areas, there is a variety of naturally fire resistant timbers that are suitable for flooring such as red ironbark, blackbutt, spotted gum and silvertop ash. Many other timbers can be treated with fire retardant treatments such as Firetard I20 from Fire Retardant Technologies .
Walls – There are a number of non combustible building materials that can be used in the building of external walls, giving flexibility to architects wishing to design buildings that are both attractive and resistant to fires. These include masonry, mud brick, aerated concrete and brick veneer. Companies such as Austral Bricks and Krause Bricks provide a large variety of standard and boutique bricks to help create truly individual constructions.
Steel and fire resistant timber framed walls can also be used in building, which should then be sarked on the outside before being clad with suitable protective materials. Dynamic Composite Technologies is one company that supplies innovative new sarking membranes. It is essential to ensure that all external walls are correctly covered, sealed, overlapped or butt jointed at all joints in order to prevent gaps.
Cladding – The most appropriate type of cladding to use to increase fire resistance of a property are 6mm or thicker fibre cement or steel sheeting. BlueScope Steel and Composite Global Solutions are two companies that offer very different external walling solutions. There are a number of innovative products such as DecoWood from Decorative Imaging that can be used to give a realistic wood like finish to both aluminium and steel.
Windows and skylights – It is essential that windows are well fitted and draft proof. Toughened glass of 5mm or thicker gives the best protection in the event of a fire. There are many companies who can supply fire resistant windows that are also architecturally appealing such as Trend Windows & Doors and Viridian . Window frames should be made from metal, metal reinforced PVC or fire retardant wood.
In high risk areas it is also important to fit bushfire screens made of corrosion resistant steel, aluminium or bronze mesh with perforations of no more than 2mm or shutters made from non-combustible materials, such as those available from Ozroll Industries .
Doors – External doors should be made from non-combustible materials or solid wood of at least 35mm thickness. Glazed doors should be 6mm or more and follow the same guidelines as windows. Technical Protection Systems offers an attractive range of fire resistant sliding doors. All external hardware, such as door handles should be metal and frames should be metal, metal reinforced PVC or fire retardant timber.
Doors should be tight fitting with weather strips at the base. As with windows, in higher BAL areas bushfire screens or shutters are needed for additional protection.
Roofs – When designing a roof it is important that valleys are kept to a minimum to avoid trapping embers, so a dual sloping pitched roof is ideal. As with clad walls, roofs should be fully sarked and roof to wall junctions need to be sealed with any openings fitted with non-combustible ember guards, such as those from The Leaf Man Gutter Guard .
Metal and fibre cement or non-combustible tile roofing are ideal materials for roofing. Monier Wunderlich and Bristile Roofing are just two of Infolink’s contributors who supply a variety of fire resistant roofing solutions.
For buildings in Victoria it is important to refer to BAL requirements. Whilst it is not necessary for properties constructed before 11 March 2009 to adhere to the BAL guidelines, retrofitting will help to make older buildings safer and less likely to be destroyed in the event of a fire. Useful guidelines can be found at the Building Commission website.