Photos: FLACHGLAS Wernberg GmbH
The Fraunhofer Gesellschaft recently chose to use SIGLAPLUS® laminated safety glass from FLACHGLAS Wernberg for the renovation of the facade at its Munich (Germany) headquarters. SIGLAPLUS® laminated safety glass is produced with high strength, high stiffness DuPont™ SentryGlas® interlayer, and combines required levels of safety performance with particularly low weight.
As a consequence, the existing supporting structure, which had been originally designed for use with toughened safety glass, could continue to be used, leading to the cost-efficient completion of the overall renovation project for the extensive facade.
During the renovation and refurbishment of facades there is a growing preference to replace existing panels made of toughened safety glass with those made of laminated safety glass. Benefits of laminated safety glass include the fact that, in the event of breakage, glass fragments remain adhered to the interlayer so that the panel remains almost entirely intact within its fixing and post glass breakage strength is high.
However, because standard laminated glass with a PVB interlayer, providing the same load capacity as toughened safety glass, is considerably heavier, its usage as a replacement can often involve the considerable costs of renewing or reinforcing the supporting structure. The lower weight of laminated safety glass with SentryGlas® interlayer now enables more cost-efficient renovation projects.
This was the situation encountered by the Fraunhofer Gesellschaft at its headquarters in Munich. Its facade had originally been completed with toughened safety glass, which was to be replaced with laminated safety glass as part of a modernization project. Standard laminates with polyvinylbutyral (PVB) would have exceeded the load capacity of the supporting structure and the metal panel frames, and would have required extensive modifications to the construction.
FLACHGLAS Wernberg calculated – with DuPont’s assistance – that a laminate consisting of two 5 mm thick toughened safety glass sheets made of low-iron float glass, with a 1.52 mm SentryGlas® interlayer, would be able to withstand the expected loads. Because the overall thickness of the glass (10 mm) was the same as the toughened safety glass panel used to date, its use as direct replacement was approved by the structural engineers.
This solution was therefore considered the most cost-effective alternative, despite the principally higher cost per square meter of the glazing, because no further construction activities were required. Overall, a total surface area of 1700m2 was restored as part of the project. Planning and implementation of the modernization project was carried out by Atzinger Glasbau GmbH of Osterhofen-Altenmarkt (Germany).
In comparison to standard PVB interlayer, SentryGlas® interlayer is over 100 times stiffer and five times stronger than PVB. This enables an almost perfect transmission of load between the two sheets of glass in the laminate. This means that laminates with SentryGlas® show less than half the rate of deflection when compared to laminates with PVB, when under the same load, and almost the same behavior as monolithic glass of the same thickness.
They are able to withstand significantly higher impacts than traditional laminates with PVB, and, in the event of glass breakage, retain a considerably higher post-breakage strength. Laminated safety glass with SentryGlas® was granted the ‘Allgemeine bauaufsichtliche Zulassung’ (‘general approval for use in construction’) in Germany at the end of 2009.
Laminated safety glass with SentryGlas® is used in architectural projects around the world such as glazed balustrades, floorings, staircases and pedestrian bridges. In all of these applications, the reduced weight of the glazing has a not insubstantial effect on transport costs. After all, if a laminated glass panel with SentryGlas® interlayer is approximately one third thinner and lighter than a panel of the same performance made with a PVB interlayer, then the transport capacity increases proportionally.
Moreover, it is often the case that glass construction companies are able to use standard lifting equipment when handling laminated safety glass with SentryGlas®, whereas heavy panels with a PVB interlayer may well require the services of a specialized company. Finally, the use of thinner laminated safety glass panels contributes to a more sustainable form of construction: if less material is required for manufacturing, then fewer resources are consumed and the environmental footprint is reduced.
FLACHGLAS Wernberg GmbH (www.flachglas.de) is part of the FLACHGLAS Wernberg Gruppe and represents seven decades of expertise in glass refinement. One of the leading glass processors in Europe, the company’s approximately 1000 employees produce insulating and safety glass on modern glass production machinery within the company’s six sites in Germany and Switzerland. With a total of 630 employees, Wernberg is the company’s largest site with very high levels of technical production capability. Its products are principally use for glazing in construction, railway and shipping.
Atzinger Glasbau GmbH, Osterhofen-Altenmarkt (www.atzinger-glasbau.de), is a company with many years of experience in architectural glazing. Its range of products and services include project glazing, facade engineering and the structural use of glass, all-glass systems, glaziery, refurbishment projects, crane work and the rental of glass assembly equipment.
DuPont Glass Laminating Solutions provides materials, services and innovations to makers and specifiers of laminated glass. It helps create a better world by improving home protection and automotive safety, and enabling design of stronger, more energy-efficient buildings that let in more natural light.
DuPont is a science-based products and services company. Founded in 1802, DuPont puts science to work by creating sustainable solutions essential to a better, safer, healthier life for people everywhere. Operating in more than 90 countries, DuPont offers a wide range of innovative products and services for markets including agriculture and food; building and construction; communications; and transportation.
SIGLAPLUS® is a registered trademark of FLACHGLAS Wernberg
The DuPont Oval, DuPont™ and SentryGlas® are registered trademarks or trademarks of E. I. du Pont de Nemours and Company or its affiliates.
This press release is based on information provided by:
Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V.
Abteilung Bauangelegenheiten/ Liegenschaften
Contact: Michael Weese
Telephone: +49 (0) 89 12 05-33 13
FLACHGLAS Wernberg GmbH
Nürnberger Straße 140
Contact: Ulrike Warnke
Telephone: +49 (0) 96 04 48-357
Atzinger Glasbau GmbH
Contact: Ludwig Atzinger
Telephone: +49 (0) 99 32 40 23-92
DuPont de Nemours (Deutschland) GmbH, Hugenottenallee 173 - 175
Telephone: +49 (0) 61 02 18-26 38