THE BUILDERS CHOICE Truss and Frame Construction
Self pierce riveting High-tech fastening in the form of self piercing riveting (SPR) started life in Australia in the early 80s. SPR is used to assemble cars, trucks, silos, steel frame houses and many other products around the world without the sparks, dust, smoke and noise associated with welding. For the same reason that car companies rely on SPR to assemble the whole vehicle body, fabricators of steel framing rely on it as a quick, consistent, reliable, high strength fastening method. SPR does not need pre-punched holes or post-painting, the rivets are auto-fed on a tape so that, at the press of a button, a rivet is set with continuous quality. Virtually weightless, the rivet tools are suspended overhead from an XY rail system to cover the full area of the wall frame or truss. Small locating dimples can be rollformed into the stud and plate and riveted over when placing one or multiple rivets in each joint, an advantage in cyclonic areas requiring higher strength joints. New homes more bushfire-resistant at lower cost Recent bushfires have again demonstrated the destructive power of ember attack. In fact CSIRO post-disaster surveys of bushfire damage typically find that some 90% of houses in bushfires are destroyed due to ember attack. However houses constructed with non-combustible building products have an inherent benefit as they cannot burn when subject to ember attack. As a deemed-to-satisfy solution in the National Construction Code, the National Association of Steel-Framed Housing (NASH) Standard for Steel Framed Construction in Bushfire Areas can be used for the design of steel framed houses in designated bushfire areas.
92 The Builders Choice Magazine – March 2018
The NASH Bushfire Standard was developed from full scale testing of building assemblies by CSIRO using the most powerful bushfire simulator in Australia, which is located at the NSW Rural Fire Service training centre near Mogo, NSW. The NASH Bushfire Standard is based on non-combustible construction. In a nutshell, basically anything that might be reached by an ember or subjected to a radiant heat flux of 40 kW/m2 must be made from non-combustible material. The Standard covers dwellings with steel floor, wall and/or roof framing, steel roofing and a range of non-combustible wall claddings. Some of the benefits of using the NASH Bushfire Standard for design of homes in bushfire areas include: For major building elements, one solution for homes constructed in BAL-12.5 to BAL-40 and another solution for BAL-FZ Steel fascia can span up to 1200mm Steel roof cladding is not required to be sarked for BAL-12.5 to BAL-40 and normal sheeting installation can be used without additional sealing Normal component clearances and workmanship may be used on the building exterior. If the building is weather and verminproof, component detailing is adequate The format of the Standard facilitates easy selection and checking of the solution for each building element. For more information on designing steel framed houses in bushfire areas or to purchase the NASH Standard in PDF or hard copy, visit www.nash.asn.au/nash/publications/nash-standards .