7 World Trade Center

Outstanding Achievement | Exterior Lighting

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Photos: David Sundberg/Esto

Publication date: July 1, 2007

Entrant Cline Bettridge Bernstein Lighting Design

Before design began on 7 World Trade Center, architect David Childs of Skidmore, Owings & Merrill (SOM) outlined a daunting task for his team. The project, he said, should set the bar for design and technical considerations—environmental sustainability, urban sensitivity, construction detailing, and security—for all future buildings to rise at Ground Zero and the surrounding area. As part of their response to this directive, the architects pulled 7's footprint 115 feet back from the original eastern site boundaries, restoring the path of Greenwich Street through lower Manhattan, and in turn creating a triangular-shaped public plaza. The tradeoff to restoring this piece of the city's fabric was the resulting smaller footprint and the necessity for the 10 Con Edison transformer vaults programmed for the site to occupy a larger portion of the building's base. In this configuration, the first 80 feet of the 741-foot-tall structure was consigned to a windowless concrete block, above which the tower's glass curtain wall begins (right).

SOM's concept envisioned a cube of light embedded within the concrete box that would first appear in the lobby, then bleed out through the walls of the windowless base, and shine up into the curtain wall, linking podium and tower. The architects called on Cline Bettridge Bernstein Lighting Design (CBBLD), who could take SOM's concepts and make them work fixture to fixture, and James Carpenter Design Associates (JCDA), whose expertise lies in controlling light with surface and material. In collaboration with JCDA, the architects developed a cladding surface for the Con Edison vaults that interacts with electric as well as natural light—a screen-wall system composed of 5-foot-wide modular panels of varying height that incorporate two surfaces (interior and exterior) of vertically strung stainless-steel bars. During the day, sunlight plays across this patterned surface in much the same way that it moves across the slightly reflective coating on the low-E glass of the curtain wall. At night, the inner screen layer takes over, acting as a reflective backdrop to a customized LED lighting feature designed by CBBLD (see image gallery).

Inside, the light feature takes the form of a point-supported-glass-clad box, which fills the upper portion of the double-height lobby volume. While the architects decided on blue as the color of the curtain wall light feature for its peaceful, calming effect, its lobby counterpart, which serves practical lighting purposes during the day, had to glow white (see image gallery). As daylight wanes the lobby volume transforms into a violet-glowing space. Then, at twilight, the lobby transitions to a cool blue color. Rather than flip a switch at an appointed hour to go between day and night modes, CBBLD created a smoother transition by throwing a bit of red into the mix. They also chose fluorescent lamps for the interior instead of LEDs. Hidden behind the glass, which has a light-diffusing interlayer, the fluorescent fixtures are composed of three-lamp strips on dimming ballasts that control each lamp separately. Each fixture holds three T5s with color in the phosphor—one blue, one red, and one white. This avoided the dimming effects of colored gels and allowed for an even tone of light.

The designers' challenge was to find a way to fuse the structure into a cohesive architectural experience. Their solution was light; a testament to what can be achieved when lighting and architecture become one. A|L

jury comments

A sophisticated, elegant solution that in its constraint is extremely compelling. | Integral to the design concept, colored light is used in a meaningful way to create a mood, yet the project's identity and success is not solely based on the color.


Project Location: New York Developer/Owner: Silverstein Properties, New York Architect: Skidmore, Owings & Merrill, New York Lighting Designer: Cline Bettridge Bernstein Lighting Design, New York Collaborating Artists: James Carpenter Design Associates, New York (podium screen wall); Jenny Holzer, New York (art wall installation in lobby); Kinecity, Fair Haven, New Jersey (motion camera for podium screen wall) Landscape Designer: Ken Smith Landscape Architect, New York Photographer: David Sundberg/Esto Project Size: 1.7 million square feet Watts per Square Foot: Gold LEED certified Manufacturers: for building: Cathode Lighting Systems, Design Plan, Edison Price, Kim Lighting, LED Effects, Legion Lighting, Lighting Services Inc., Lightolier, Linear Lighting, NeoRay, Osram Sylvania, Specialty Lighting Industries, Venture Lighting; for Triangle Park: B-K Lighting, Drama Lighting, Lumenyte, Selux