New Wave

Curved glass shapes design
Peter Stattler
October 1, 2013
Michigan State University commissioned this unique curved Schott Amiran anti-reflective glass structure to house the university’s championship trophies. Aaron Glass, Lansing, Mich., was the contract glazier for the project, located within the Michigan State University Breslin Student Events Center, Alfred Berkowitz Basketball Complex.

Whether you’re walking past the IAC building in Manhattan or the Apple Store in Santa Monica, Calif., it’s hard to miss the architectural medium of the day: curved glass. As a design element, curved glass introduces movement and dimension to traditional structures that have previously been flat, linear or static. As a building component, curved glass incorporates new material technology that enables coatings, interlayers and patterns to bend with the glass—resisting warping or distortion—for a functional, visually appealing design.

New technology

New technologies allow fabricators to produce curved glass more economically, while simultaneously expanding its design possibilities. Previously, fabricators formed curved glass from a mold or cast: an expensive technique. Then came cold bending: a technique in which the flat glass was pushed into a frame to give it just a slight bend. The IAC building in New York City is a prominent example of this type of curved glass.

Today, adjustable bending ovens eliminate the need for molds. These ovens have hundreds of different pieces that can be arranged to curve the glass to a particular degree. Once in the oven, the flat glass slumps onto the pre-arranged bed and takes the desired shape.

Beyond new fabrication methods, curved glass has also benefited from more robust coatings and interlayers. While at one time coatings would warp when bent with glass, new proprietary technology allows them to curve and still maintain their patterns and effects. The coatings and interlayers that are now available open up a number of new options for curved glass, including anti-reflective coatings, dichroic coatings, semi-transparent mirror coatings, as well as insulating curved glass units with metal meshes—and even wood louvers.

New applications

The ability of curved glass to incorporate energy efficient coatings and interlayers is perhaps most important to its use on building exteriors, where it is now a viable option for high performance building envelopes.

Since curved glass is still more expensive than regular flat glass, architects typically only use it in certain areas of a design to ensure they can stay within the budget parameters. An architect might use curved glass in a building façade, for example, to create a “flowing” feel that changes the whole look of the building.

Perhaps the most high-profile example of the use of curved glass in building exteriors is Apple’s design for its new headquarters, which includes 40-foot lites of concave glass on the exterior to allow more light into the space. This large-scale adoption of curved glass is still rare; however, look for it to become increasingly common as the manufacturing process grows more efficient through the adoption of curved and curved tempered glass ovens currently used in the transportation industry.

Along with curved glass on the exterior, decorative curved lites on the interior are adding eye-catching features to buildings. Schott is currently working on a staircase, for example, that will feature high-quality dichroic bent glass. Previously, the process of creating this glass was so complex that a fabricator would have to make eight or nine panels to get a single good one. Now, it can be done without difficulty and almost no waste due to coating formulations that ensure the coatings do not warp, crack or distort under the hightemperatures they are exposed to in the post-processing of the glass. Whereas in the past, such a project would require segmented pieces of flat glass to prevent coatings from wrinkling and distorting, now the glass can curve around the stairs, and the dichroic coating curves with it, changing color depending on the angle at which you look at it.

Interior designers are also catching on to curved glass for room dividers or full walls. In some applications, the glass might only be 6 feet tall, perhaps to separate a restaurant area from the rest of a casino, offering privacy while maintaining air flow throughout the space. Designers are now using bent glass in place of bent plastics in many interior spaces such as conference rooms.

The trend will likely take off as technology continues to advance, further decreasing the expense of curved glass and multiplying design possibilities through coatings and interlayers that can be curved right along with the glass. For interiors and exteriors—for offices, hotels, apartments and more—the future of glass is curved.

The author is architectural sales consultant for the Architecture + Design group of Schott North America, Inc., and is based at the company’s North American headquarters in Elmsford, N.Y. Stattler joined Schott in 1999 and currently consults with architects on glazing solutions for interior and exterior applications.