NEWSLETTER SUMMER 2011

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1 NEWSLETTER SUMMER 2011 A word from our Chairman In February 2011, North Queensland experienced Tropical Cyclone Yasi. The Cassowary Coast was the most dramatically affected and is still working to recover. This edition of the CTS Newsletter includes articles on the damage investigation performed by the CTS team and the subsequent report that included 14 specific recommendations. It also includes an article on the workshop of key stakeholders that was held in Brisbane in July 2011, to work towards implementation of agreed recommendations. The Newsletter also includes articles on work to date on specific recommendations. Articles focus on roller doors, tiled roofing, sheds and solar panels. I would also like to take this opportunity to thank the Master Builders Foundation for the donation of a new 4WD dual cab utility. As an independently funded organisation, the Cyclone Testing Station relies on donations such as this to support its work in the community. The new vehicle will be of enormous benefit to the CTS team and highlights the support that Master Builders have always given to CTS activities. John Galloway, Chairman, CTS Management Committee Roller Doors and Sectional Doors Of the approx houses inspected after TC Yasi, 29% of the houses that had roller doors experienced door failures. Since the wind speed was less than the design wind speed, these doors should not have failed. This begs the question of whether door performance is being adequately evaluated as part of the design and construction process. There is an Australian/New Zealand Standard for Domestic garage doors; AS/NZS It is not referenced in the Building Code of Australia and in fact the BCA does not make any direct reference to performance requirements for roller doors. There is, however, an implicit requirement that door performance should be assessed. Clause of AS/NZS :2011 clearly states Closed doors (including roller doors) and windows shall be considered as openings unless they are capable of resisting the applied wind pressures in all regions (and impact loading from wind-borne debris in Regions C and D). It would probably be better if AS/NZS 4505 was directly referenced in the BCA, rather than indirectly via AS/NZS It is understood that the Australian Garage Door Association is preparing a Proposal 2010 Cyclone Testing Station School of Engineering & Physical Sciences, James Cook University, Qld, Phone Fax jcu.cts@jcu.edu.au Web Page 1

2 for Change for a revised version of AS/NZS 4505 to be submitted to the Australian Building Codes Board for consideration. The proposal is that the revised version of AS/NZS 4505 should be referenced in the National Construction Code in Tiled Roofs Damage was observed after Cyclone Yasi to concrete and terracotta tiled roofs. Particular issues included the failure of part tiles around hips, as well as the failure of ridge and hip capping. The Standards Australia has reconvened BD008 to revise the tiling standard AS2050 (Tiling Standard) to consider changes to the methods of specifying ridge and hip tile connections. It is anticipated that a revision to this standard will be issued in the first quarter of 2012 to reflect these changes. The RTAA has identified the use of adhesive fixing techniques and the absence of any mechanical fixing as a contributing factor to the poor performance. The RTAA proposed that AS 2050 should be reviewed with the aim of moving towards mechanical fixing techniques such as clips for all part tiles and for ridge and hip capping. Part tiles currently do not require fixing at all in the Standard and these part tiles are often the main area of attachment for ridge and hip capping, so it is not surprising that failures have occurred. The proposed change to this Standard (which is a current BCA referenced document) has begun. Building Codes Queensland recently issued a Building Newsflash ( wsletter/newsflash-483.pdf) stating that mechanical fixing is required for C2 and C3 areas. Once the mechanical fixing issue is resolved, CTS would be keen to see other issues addressed that have been identified in previous Technical Reports, including water ingress as identified in CTS Technical Report No 55 on the Brisbane storms and in other earlier reports. AS/NZS refers to the need to conduct a cyclic test on all products that are to be used in cyclonic areas where any element may be subject to fatigue. Tile clips should fit this definition, yet there is no current test method to identify the cyclic regime or other testing requirements for tiled roofs to be used in cyclonic areas. Consideration should be given to the development of generic testing requirements for all building materials, including steel, tile and other cladding systems and possibly doors, roller doors and windows, unless any of these have their own testing requirements. It is further proposed that the AS 4040 series could form the basis of an initial test method. Sheds In recent years steel sheds have become increasingly common in residential and commercial applications. Larger sheds tend to include hot rolled portal frames with steel cladding, while smaller sheds often used cold-formed steel frames and cladding. Page 2 of 6

3 Prior to TC Yasi, most of the shed damage had been on smaller structures with coldformed steel frames and some larger structures that may have had hot-rolled frames but used unusual engineering details. In TC Yasi, there was again some damage to cold-formed steel framed sheds but there was perhaps a higher incidence of failures of hot rolled steel framed sheds than had been seen before. Some of the hot rolled failures included similar design details and it is possible that some of the failed sheds may have had common design elements. Over the last 10 years, the Australian Steel Institute has worked to foster good engineering practices in cold-formed steel sheds, through the establishment of the Steel Shed Group. This group and its members companies have developed engineering guidelines for the design of cold-formed steel sheds, along with an engineering audit process that was initiated in Sheds built in recent years by members companies should comply with relevant Codes and Standards but there are three outstanding issues: The design guidelines do not yet consider catenary forces from wind-locked roller doors and this could lead to failure. It is important that shed design procedures make provision for roller door forces both normal to the door and in the plane of the door. The design guidelines are not mandatory and do not apply to companies that are not members of the Steel Shed Group. The design guidelines do not apply to hotrolled steel sheds, although there are other Standards that should cover these. It is recommended that consideration be given to referencing the Steel Shed Group s engineering principles in the National Construction Code or in a Standard that is referenced in building regulations, so that they are mandatory for all suppliers. Solar Panels Solar panels are an appropriate technology for tropical environments due to the high levels of solar radiation but they have a high capital cost and they need to be properly evaluated to ensure that they can survive a design wind event without the need for premature replacement. A solar panel that disengages not only requires replacement but potentially becomes flying debris, with associated risks to life and property. Many of the panel system sold in Australia have been developed in Europe and elsewhere and have been tested using a static pressure of +/- 2.4 kpa. Industry literature states that this is equivalent to a 130 km/h wind event. This may be adequate for some non-cyclonic areas but we know that the design wind speed for cyclonic areas in North Queensland and Darwin is around 250 km/h and in northern WA even higher. Some systems have also been tested for a positive (downward) static pressure of 5.4 kpa, to simulate heavy snow loading but we have not seen evidence that systems have been tested for significant uplift pressures that can occur in cyclonic areas. Uplift may increase the possibility of the panel itself disengaging and will increase the load on fastening systems. A further issue for designers is that there is no codified information in either AS/NZS or AS 4055 for the pressure coefficients that apply to solar panels installed on a roof. CTS recently completed a wind tunnel study on behalf of BCQ to develop pressure coefficients for solar panels used in roofing applications. This information will be submitted for consideration in the next amendment of AS/NZS , to Page 3 of 6

4 simplify the process for panel designers to develop safe and efficient systems. It is recommended that manufacturers are required to demonstrate that their panel systems, including any fixings to the roofing structure, are able to resist the design wind loads for any installation. This process does not need to be complex but should include consideration of any fatigue-sensitive elements in cyclonic areas (just like all building elements and systems that are installed in high wind regions). Anemometers There was unanimous agreement amongst the CTS team that participated in the Yasi investigation that a reliable and efficient means is needed to collect more accurate data of wind speeds across the affected region. An enhanced network of fixed anemometers might be one solution but this could be prohibitively expensive to develop and maintain. The CTS is currently exploring options for the establishment of a network of mobile anemometers that could be set up in the path of an impending cyclone. Some partners have already been identified and CTS would be interested to hear from other parties who may wish to support this important initiative. Workshop The Cyclone Testing Station regularly conducts investigations after severe wind events, often completing reports for Governments and other interested parties. Historically we have considered that our role is largely complete once we have delivered the report. We have assumed that others will consider the report and act upon the recommendations as appropriate. Having now seen similar issues arise in many investigations, it is clear that any action taken previously has not been sufficient or effective. One possible reason for this is that like us, everyone is expecting someone else to act. In reality, however, progress is only possible when all parts of Government and industry act together to tackle the problem. With this in mind, the Cyclone Testing Station took the initiative of organising a workshop of key stakeholders after the Cyclone Yasi investigation. The workshop focused on the recommendations of CTS Technical Report No 57, with the aim of identifying further actions and participants. All participants appeared enthusiastic about the concept and flow of the workshop. Good progress has been made on some topics, including those discussed in this newsletter. There is no current plan for a follow-up workshop but this could be considered if there is interest. From our perspective, while considerable effort went into organising the workshop, we would much prefer to do that again if it helped to initiate action than to experience another cyclone and find the same problems! CTS Web Site This newsletter, along with previous newsletters, is available from our web site at: We are pleased with recent progress aimed at refreshing our web site, which we expect to complete soon. This will help us to do a better job of staying in touch with you, including providing a better service for mobile devices. From our perspective, another advantage of the new site is that maintenance should be far easier for our staff, which will help them get information to you quickly. The team did a good job of this during Cyclone Yasi but the process to achieve this was clumsy. We expect to be able to achieve Page 4 of 6

5 an even better result with less effort in the future. To receive future newsletters via please subscribe on the web site. Donation of Vehicle from Master Builders Foundation The CTS team will now be better equipped for its field studies thanks to the donation of a 4WD vehicle from the Master Builders Foundation. He thanked the Master Builders Foundation and the Master Builders Association members who support it, stating that the vehicle will be a great asset in achieving the common goals of the organisations involved. The Station relies heavily on support from groups such as the Master Builders Foundation to conduct its research and community education. The Master Builders Foundation is the fundraising and community support arm of Queensland Master Builders Association Industrial Organisation of Employers. It is funded voluntarily by Master Builder s members and was established to assist both building and construction industry participants and their families and other community groups in need. The Foundation's mission is to provide support to Queensland-based people, projects and programs. Mr Graham Cuthbert, Executive Director of Master Builders, said the organisation has been a long-term supporter of the work of the Cyclone Testing Station. We recognised the CTS had a need for better equipment, particularly in preparing for investigations of building performance such as that after Cyclone Yasi. The vehicle is clearly identified with both the Cyclone Testing Station and Master Builders Foundation logos, as well as the clear message outlining the goal of the two organisations for Safer Houses and Communities, Mr Cuthbert said. Manager of the CTS, Cam Leitch, said there were notable similarities between the Master Builders Foundation s aim to assist the community and the Cyclone Testing Station s aim to minimise loss and suffering as a result of high wind events. Cyclone Sunday 30 Oct 2011, Townsville Every year, the CTS participate in the Cyclone Sunday Emergency Expo, a community awareness event organised by Townsville Local Disaster Management Group in conjunction with Townsville City Council, to assist the local community in their preparations for the oncoming season. This year we handed out pamphlets, and gave presentations to the local community with the aim to raise awareness about the main causes of damage to the houses in cyclones and preventive measures that can be taken to reduce the risk of damage. The CTS staff members also addressed a number of queries from the local residents about design and performance of roller doors, windows, solar panels and other components in cyclones. Page 5 of 6

6 us, having represented Master Builders on our Management Committee for many years and having been our Deputy Chairman for the last 4 years. Cyclone Sunday Emergency Expo, Townsville 2011 Staff Changes We would like to take this opportunity to thank our previous Chairman, Doug Meecham, for his enthusiasm and dedication over many years. Since our last Newsletter Ulrich Frye, our Senior Testing Engineer left the Cyclone Testing Station to study in Sweden. Actually Ulrich continues to work with us remotely on a part-time basis, so perhaps we can say that we have now opened our latest CTS office in Sweden! Tony Walther joined us in October, as our new Senior Testing Engineer. We welcome Tony, who brings some significant previous experience including five years at the Building Research Association of New Zealand. We also welcome our new Chairman, John Galloway to the role. John is no stranger to The Cyclone Testing Station wishes to thank all of our Benefactors and Sponsors for their continued support Page 6 of 6