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An Architecture of Glass That Filters Sunlight, Bends in the Wind

New technologies have made glass, that ancient, fragile material made from molten sand, suitable as an architectural building block, too. New York architect and glass artist James Carpenter is the best-known innovator in the field, work for which he received a $500,000 MacArthur Foundation "genius" award in 2004.

"Light is really the subject that most interests me,” says James Carpenter, “and glass is the material that allows you to explore and control and manipulate qualities of light." Carpenter began his career as an architecture student, then veered off into glass art and technology, and then back into what you might call “glass architecture.”

In the last twenty years, partly due to Carpenter's innovations, strong new forms of glass have been developed that can be used as a structural material, whether for staircases, walkways or walls -- transparent walls that admit sunlight, but are coated invisibly to keep out too much heat.

"Most people find this fairly hard to believe,” Carpenter says, “but glass in many respects is much stronger than steel. I mean, we have this presumption about glass as being very fragile, and it breaks, and those are all true. But if you use it correctly, in compression, and use it in specific ways, it really does have a strength that's much greater than steel.”

For example, new forms of "safety" laminated glass can be laced together on cables, creating flexible walls that can absorb the impact of hurricane winds or blast forces, almost as a tennis racket absorbs the impact of a ball. As Carpenter puts it, "You take the energy and allow the structure to deform slightly, and then re-find its original position."

These tennis-racket walls are used both in Carpenter's glass atrium at the Time-Warner Center in New York (the Center's lead designer was David Childs of Skidmore, Owings and Merrill) , and at the new Seven World Trade Center, the first Ground Zero skyscraper to be rebuilt -- set to open in April -- to which Carpenter contributed the facade and base to David Childs' design.

You can see other James Carpenter works in cities around the United States, and in other countries, including Germany, China and Saudi Arabia. But his most high-profile projects are in his home base of New York City. For the roof of a new subway station in Manhattan by lead architects Grimshaw and Partners, Carpenter designed a glass-enclosed perforated metal dome. He shows a model of the design to a visitor to his firm’s offices in an old industrial building downtown.

“This form that I'm holding is a sort of very delicate, diaphanous metal structure that floats inside that glass volume,” Carpenter says, “and the purpose is to take daylight coming down through this oculus or skylight at the roof, passing through, and then hitting the metal skin, the light then is reflected further down into the subway station. So, if you walked through this space every day, you would begin to realize that when you looked up at it and saw the sun shining in, you could effectively tell what time of year it is. It’s a kind of sun dial."

Last spring, Carpenter's firm, James Carpenter Design Associates, won a competition to design New York City's new Moynihan Station, an expansion of a current railway hub, Pennsylvania Station. It will be located across Eighth Avenue in a 100-year-old landmark neoclassical-style building that Carpenter's plan leaves largely untouched, he says, “to avoid doing anything to the original fabric, but to have a glass roof that floats over the building and around the outside.”

Standing next to a large model of the design, Carpenter points to the re-opened “moats” and other openings that will carry light down to the shops and train tracks underground. “We’re trying to use elements of light to organize the space, and to provide a means of orienting yourself as you go through the space,” he says.

Adding nuance and beauty to everyday experiences -- walking through a subway station or along a city street -- is the purpose of his experiments with light and glass, Carpenter says.

Further north in Manhattan, a massive flat glass sculpture by Carpenter shimmers on a brick wall overlooking Columbus Avenue. It looks like a huge window, but that’s actually reflective glass hung on a blank wall, with short projecting "fins" of dichroic glass coated to divide the visible spectrum of light – so that the colors shift as you walk by, and as the sun passes overhead.