The Perth coastline is known for its sensational, retina popping views. So for glass balustrades, dispensing with visually intrusive handrails makes perfect sense. After all, why would you ruin a multimillion dollar outlook with a handrail?
With conventional frameless glass balustrade systems, the Building Code of Australia (BCA) requires a fall arrest to prevent injury from a fall should the glass panel break. Typically this fall arrest comes in the form of a handrail, which is paired with a frameless glass balustrade panel made from a single piece of toughened glass. The glass has holes drilled for the handrail system to be mounted into. Standard frameless glass balustrade systems are suitable and practical for a variety of applications, and can also create opportunities for some great feature material use such as blackbutt timber handrails.
However, for installations with sweeping views, or where glass is used to create a sense of uninterrupted space, a handrail may obscure the outlook or create barriers within the area. In some instances, tricky angles and changing levels of balustrade can result in challenging manufacture and installation of a handrail, which can add additional cost and complexity to the project.
Products like Vista View Frameless Glass Balustrades offer a truly frameless balustrade solution that allows installation without a handrail, while still satisfying the BCA criteria for provision of a fall arrest. In the case of VistaView, the fall arrest is created by laminating two pieces of glass together into a toughened laminated glass makeup that incorporates the use of a specialised structural interlayer known as SentryGlas® Plus, or SGP. The standard interlayer typically used in glass manufacturing is Polyvinyl Butyral (PVB), which is a far softer compound that is unable to provide a high level of structural integrity.
Manufactured by Kuraray, SGP is designed for structural glazing applications such as trafficable glass floors and canopies that are subject to high pressure loads. When utilised within a glass balustrade, the post glass breakage strength of SGP provides a permanent barrier in the event of panel failure, a characteristic that standard PVB interlayers are unable to produce. The graph at left shows the center displacement of a broken glass panel using the PVB interlayer compared to SGP. The displacement of the glass using the PVB is far greater and clearly would be unsuitable in a vertical (balustrade) installation where the requirement is to prevent a fall through the glass. To gain a clearer understanding of the difference between the two types of interlayer, the below videos demonstrate the difference in post breakage strength.
PVB INTERLAYER SGP INTERLAYER
Creating a fall arrest through the use of a structurally laminated glass panel rather than a handrail is not considered by the BCA as a standard balustrade solution. As such, to ensure the balustrade installation remains within code requires obtaining BCA compliance, which is achieved on a case-by-case basis under the ‘Alternative Solution’ provision. A suitably qualified Structural Engineer undertakes a deflection and safety analysis based on proposed panel sizes and fixings, then if compliant, issues an engineering certification. This certification is required prior to any manufacture or installation of glass.
Structural engineering firm WirraWonga Consulting, based in Melbourne, works regularly alongside our glass and glazing consultants to specify and certify Vista View frameless glass balustrade installations. “Typically, internal or external domestic applications require two sheets of toughened glass laminated with a 1.52mm SGP interlayer” comments Wirrawonga Managing Director Stuart Rooke, “But as we move into commercial applications like shopping centres, airports, and restaurants, the need to apply different loads and thicknesses increase significantly. Equally, different fixing methods affect our computations, as do wind loads, panel heights and physical locations.”
A variety of fixing systems are certified for Vista View panels, including channel fixing, spigot or bolted anchor fixing methods. “Vista View is ideal for the applications we certify for,” Rooke says. “We’ve completed over 500 certifications in the last two years alone, and have encountered no problems from a safety or regulatory point of view. We are extremely confident that the SGP interlayer creates a glass balustrade solution that is becoming the choice of progressive architects and cutting edge construction companies.”
VistaView frameless glass balustrades are designed and manufactured locally in Perth, and are available in tinted, clear or even digitally printed glass. To find out how we can help you achieve a handrail-free, spacious design for your current or upcoming project, please get in touch via the details below, or through the form on our contact page.