Spec Finish

Technical www.thefis.org 23 In the case of the specific product and its intended use, surprisingly, none of the guidance contains standardised methods of testing, and without a designated status, there is no route to conformity marking a kit of parts that could demonstrate compliance with essential characteristics. Peter Long, Divisional Fire and Certification Director at Optima Systems, said: “We need to be advocating the same degree of risk management in guarding as we do with fire... Both areas of construction are protecting risks to life, so both should have the same levels of attention to safe design.” So, glazing that is protecting a drop is a clear example of a safety critical product. Design and engineering considerations Since the use of frameless glazing started being specified in these environments, architects, designers and manufacturers of full height glazed partition systems and architectural glazing products have been interpreting the guidance that exists and attempting in good faith to design barriers that meet all the basic requirements, but the unique properties of the product make this difficult. In addition to the general inability to test performance; the absence of a handrail means that the glass is directly subjected to any specified horizontal loadings, loadings only need to be applied to the glazing below the design level, but apply to the entire full height panel. In engineering terms, the visually preferred dry jointing method cannot be considered a legitimate ‘retention method’ and has the impact of skewing deflection calculations, making it challenging to perform accordingly; and, perhaps most importantly, the behaviour of safety glass types post breakage in the context of frameless glazing is a crucial matter, which should be considered at specification. In the simplest terms, the glass in a full height barrier needs to resist load cases prescribed in BS 6180 and Eurocode EN 1991-1-1 and use a safety glass with Type B stay in place breakage behaviour in accordance with EN 12600. The implications of this are principally in the selection of a suitable safety glass. A full height panel of monolithic toughened glass in not prohibited within the text of BS 6180, but it is very clearly unsuitable for use in a frameless barrier, as breakage will likely result in total disintegration of the panel, leaving a full height opening in the barrier and creating loose glass pieces that can fall into an indoor atrium area or similar. FIS technical note The good news is that observing prescribed loadings and giving sufficient consideration of additional wind loading factors and performance after breakage, it is possible to specify a single glazed construction that can resist loadings and will remain in place in the event of breakage even when the panel is only considered to be retained by the top and bottom short edges, allowing the area to be cordoned off for servicing/ panel replacement without posing a serious risk to building occupants. FIS has published a dedicated technical note on guarding with frameless glazing which provides detailed guidance on regulations and methodologies required to design for guarding using frameless glazing. More details will be available at https:// www.thefis.org/knowledge-hub/technical/ fis-technical-notes-industry-alerts/ Full height curved glazing overlooking an atrium Full height glazing surrounding an atrium