Thinner, lighter glass façade for Lisbon, Portugal office building
Lighter, safer laminated glass takes advantage of the strength and stiffness of DuPont™ SentryGlas® structural interlayer.
The street-facing façade of a newly-built office building belonging to Bouygues Imobiliária in Lisbon, Portugal, is formed by laminated glass panels made with strong and stiff DuPont™ SentryGlas® interlayer. The ability of SentryGlas® to create highly-resilient laminates with excellent post-breakage performance has allowed the façade engineering specialist Facal, of Santo Tirso (Portugal), to create a comparatively thinner, lighter glazing that is able to cost-effectively meet building and safety requirements and requires comparatively small point fixtures to hold the panels securely in place.
Facal, a company recognized nationally and internationally for its pursuit of technical innovation in façade engineering, developed and installed the laminated glass façade for the Explorer building at the Parque das Nações in Lisbon. Measuring 20 meters high and 10 meters wide, the façade consists of approximately 40 laminated glass panels produced by the glazing specialists Vicer of Maia, Portugal.
According to initial calculations, a laminate construction using a standard polyvinyl butyral (PVB) interlayer would require the two glass sheets to be each 12 mm thick in order to provide the required long-term resistance to the specified wind loads. Moreover, it would require a comparatively expensive supporting framework with very large fixtures would be required to withstand the weight of the panes and the additional wind forces.
However, because SentryGlas® interlayers are 5 times stronger and up to 100 times stiffer than PVB, a thinner glass construction can be used to achieve the same load-bearing capacity of the PVB alternative.
For Facal this meant that, by using a laminate construction consisting of 10 mm strengthened glass + 1.52 mm SentryGlas® + 8mm tempered glass, they were able to reduce the thickness and the weight of the panels by 25 percent. This in turn meant that the point fixing system developed by Facal to hold the panels securely in place could be made smaller, and therefore less obtrusive, than those required for the equivalent glass laminated glass panels made with a PVB interlayer. These combined benefits also result in a more cost-effective glazing solution with regard to the façade's production and installation.
The excellent post-breakage behavior of laminated safety glass made with SentryGlas® was a further critical safety factor in the selection of the DuPont interlayer for the Portuguese façade.
As a spokesperson at Facal explains: "Our primary concern was that of providing increased safety and ongoing protection in case of glass breakage and fallout. This is of particular significance in Lisbon, a city susceptible to seismic movements.
"With some of the glass panels as high as 20 meters above street level, it is essential that the integrity of the glass façade is retained, and there is no risk of fragments of glass falling on to passers-by. Thanks to its excellent post-breakage performance, and the fact that the glass fragments remain adhered to the interlayer, this is assured with SentryGlas®."
Further benefits of DuPont™ SentryGlas® interlayer include its high, crystal-clear transparency, its virtually universal resistance to yellowing and excellent edge stability.