Page 55

RCI March 2018

Project1_Layout 1 07/05/2013 CLADDING & SHEETING designed movement serviceability limits. Curtain walling and cladding façade systems will deflect due to positive and negative windloads, as well as occupational live loads. These are covered by EN 13116:2001. Typically, a project may stipulate that the curtain walling system may have the following allowable deflection limits: under the declared wind loads, the maximum frontal deflection of the curtain walling’s framing members shall not exceed L/200 or 15mm, whichever 052 MARCH 2018 RCIMAG.COM is less, when measured between the points of support or anchorage to the building’s structure in compliance with EN 13116. (Extract from EN 13830:2015) These factors may inevitably combine to preclude the suitability and therefore, use of certain systems e.g. high-density material slab products. Perimeter barriers must be installed to provide horizontal compartmentation at every floor level. Vertical cavity barriers should be provided as a minimum to fall in line with any compartment wall and more frequently if dictated by the fire strategy of the building. Products should be fitted tightly around all bracketry to restrict the passage of smoke. Where there is potential for gaps, the product must be sealed with a sealant that carries the same fire insulation and integrity rating as the perimeter barrier. All installations should be in accordance with the manufacturer’s instructions, and where fixing brackets are required, these should be fitted and spaced in accordance with a certified fire test report. Products used for fire safety installation should carry an independent third-party certification, in order to ensure that the product supplied is the same as that tested. The gap between the slab edge and the façade is often a weak point acoustically. Any products used to improve the acoustic performance must not contribute to the fire load or inhibit the performance of the perimeter barrier. Whilst specifying the correct product is vital, the quality of installation is equally as important. Contractors installing life-saving measures such as perimeter barriers and firestops must have adequate training on the particular manufacturer’s products and be qualified to install it in the first place. When it comes to saving lives and protecting businesses and property, a well-designed and installed system can make the difference. www.siderise.com More clarity is needed on cladding Aluminium composite cladding fire-rating standards need greater clarity, says Ben Jayes, managing director of Vivalda Group Vivalda Group has called for greater clarity on rainscreen cladding standards in the wake of the Grenfell Tower disaster. As of last month, the distributor of high-performance claddings and off-site fabrication specialist, confirmed that it will no longer promote aluminium composite materials (ACM) for use on high-rise applications, which fail to reach the A2 standard. The company is concerned that contractors could inadvertently make unintentional specification errors, given the complexity of the UK’s current safety standards. While the initial report on the likely causes of the Grenfell fire is not expected until spring, shortcomings in the current ‘approved inspector’ regime have created a confusing landscape for contractors. This scenario has been made worse, says Vivalda, by the widespread adoption of complex laboratory tests used by manufacturers to gain approval for so-called safe systems, which are impossible to replicate on-site. The issue of fire safety is at the very top of the agenda for contractors right now, but many within the industry are not helping to build confidence in the supply chain. We know of one manufacturer of aluminium composite materials that has put out ambiguous claims relating to how its standard material performs at a high level. But that’s not the whole story. It’s worth remembering that behind every panel lies a complex web of subframes, fixings and fire barriers, none of which, this manufacturer is prepared to detail as part of a system. The poor contractor is on the hook should there be failure in even one minor component, so confidence in the complete system’s performance is vital. Besides, setting up a rig for a lab test is one thing, replicating it on-site,18 metres in the air, is quite another. We’ve looked closely into this and decided in the best interest of clarity, to promote only aluminium composite material products that meet or exceed the gold standard of A2. Despite their best endeavours, many customers could be installing systems that may turn out not to be safe. Thus, we’ve moved to make the task of A2-standard aluminium rainscreen cladding simple – by offering only fully approved claddings and associated fixings. Ben Jayes, managing director of Vivalda Group “The poor contractor is on the hook should there be failure in even one minor component, so confidence in the complete system’s performance is vital”


RCI March 2018
To see the actual publication please follow the link above