Philadelphia's Kimmel Center for the Performing Arts Protected By DuPont Butacite®

WILMINGTON, DEL., August 2, 2002 Since its opening last December, the new Kimmel Center for the Performing Arts has garnered rave reviews from architecture critics and fans alike. This breathtaking new landmark is home to eight resident companies, ranging from the Philadelphia Orchestra to the Opera Company of Philadelphia to the Pennsylvania Ballet to the modern dance company Philadanco, each of which benefit from the innovation of DuPont Butacite® polyvinyl butral (PVB).

A soaring, 12-story high, barrel-vault-shaped atrium roof employs large panes of tempered glass laminated with DuPont Butacite® protecting what architect Rafael Vinoly calls "two jewels floating in a transparent box": the 2,500-seat Verizon Hall and the 650-seat Perelman Theater. The barrel vault is curtained on both sides in two colossal glass arches; both 'end walls' are also made of laminated glass with Butacite®.

The self-supporting barrel vault, with a radius of 87 feet and a span of 174 feet of laminated glass, is unique for its huge size as well as its striking and varied aesthetic, since it appears to "float" above the two transparent end walls. Charles Blomberg, project architect at Rafael Vinoly Architects, says, "We were inspired by the great winter garden or greenhouse architectural structures of the nineteenth century, like Crystal Palace in London. The lobby is important at the Kimmel Center; it is a place where people can gather all day and into the night in all weathers, year-round."

The Kimmel Center's roof is based on a column-free, self-supporting, 174-foot Vierendeel truss to arch across the span, and on folded glass plate action to create longitudinal stiffness. Blomberg explained, "There are no square or triangular panels of glass. Instead, the glass panels are leaning against each other at an angle of 45 degrees. The membrane of the arch therefore resembles a folded plate structure when seen close up and achieves the structural rigidity we needed; it's like window mullions holding up the building! The result is a pure, gravity-loaded arch of laminated glass that can bear snow and wind loads."

Don McCann of glass fabricator Viracon, who did the overhead glass, added, "Aside from safety and strength, three main reasons for using laminated glass for the barrel roof were solar control, aesthetic appearance and cost efficiency. The custom-designed construction is made of a 10mm layer of gray, heat-treated glass followed by a 1.52 mm Butacite® PVB interlayer, followed by a layer of 6mm glass with a Low E pyrolitic coating on the inside. Testing confirmed that we got a better U value by incorporating the coating on the inner surface: a 51 percent shading coefficient is achieved. The architects wanted a good degree of natural light coming in through the roof but they also wanted to control heat build up and glare. The gray glass gives 43 percent light transmission and also reduces reflectivity by eight to ten percent, compared to standard laminated glass."

Blomberg commented, "Laminated glass was essential for building the shading factor we needed into the glass construction. Without the Low-E coating, the solar gain would have been prohibitive. The roof has a massive surface area and its length extends for the equivalent of a whole city block! The use of laminated glass enabled us to exercise outstanding climate control.

"For the end walls, we specified that fabricator Dlubak of Blairsville, PA who did the side glazing should use two layers of 5mm Starphire low iron tempered glass laminated with 1.52mm clear DuPont Butacite® PVB. The panes of glass we used are pretty big laminated glass gives the best protection against glass fallout. The end walls invite visitors to take in the city of Philadelphia when they attend arts performances; likewise, since the facades are largely transparent at street level, passers by can see freely into the Center's impressive public plaza."

Acoustically, the Kimmel Center rivals many of the great performing arts centers in Europe, thanks to the acoustic properties of DuPont Butacite®. As many countries implement strict regulations on unwanted sound, Butacite® is an effective solution. The soft polymer layers of Butacite® laminated glass dampen the natural, drumlike movements of glass and help keep out noise.

Striking designs like the Kimmel Center can be attempted because of work that DuPont is doing with ASTM International, a worldwide standards organization. As a result, new ASTM standards are expected to be issued in 2002, with an eye toward expanding the use of laminated glass as new building codes are implemented.

The DuPont team also is collaborating with the American National Standards Institute, the European Committee for Standardization (CEN), the International Organization for Standardization (ISO) and regional groups in Japan and Australia.

During 2002, DuPont is celebrating its 200th year of scientific achievement and innovation providing products and services that improve the lives of people everywhere. Based in Wilmington, Del., DuPont delivers science-based solutions for markets that make a difference in people's lives in food and nutrition; health care; apparel; home and construction; electronics; and transportation.

For more information on DuPont Butacite, please call 1-800-438-7225 or visit www.laminatedglassnews.com.

EDITOR'S NOTE: Butacite® is a registered trademark of E.I. duPont de Nemours and Company.