CHALLENGE The Cira Centre sits across the Schuylkill River from Center City in Philadelphia, expanding the downtown skyline. The challenge for New York City–based Cline Bettridge Bernstein Lighting Design (CBBLD) was deciding how best to illuminate this “crystalline glass structure that was in no way like a traditional skyscraper,” says senior associate Michael Hennes. Trying to light the prism-like tower with no projections, setbacks, or crown to capture the lighting proved to be complicated, as the architects were adamant about not having fixtures projecting from the glass building. As a result, Hennes says the concept arose to illuminate it by creating a “wallpaper of light.”

SOLUTION Hennes notes that in 2002, when CBBLD started the project, light-emitting diode (LED) technology was still developing in regard to architectural uses. However, the technology has advanced in the past six years, and the designers were conscious of that as they worked on the lighting design and created mock-ups and renderings featuring LEDs. In the end, they were able to make an informed decision about the technology and chose to use LEDs for the building's exterior lighting as well as the illumination of the lobby and elevator cabs.

The 435-foot-tall building is highly visible as it is connected to Philadelphia's 30th Street Station and those traveling between New York City and Washington, D.C., can see it from the train. Hennes says the building owners became excited about the lighting schemes' possibilities through the use of LEDs because not only was color an option, but the technology also allows for patterns or effects on the façade. To create a wallpaper of light that wraps the building, CBBLD used 26W RGB LED fixtures that are concealed in shadow boxes behind the glass curtain wall. “The glass has a reflective quality, so by day you can't see those shadow boxes,” Hennes says. “By night, of course, the fixtures activate the surface.”

One particular challenge is that the building is adjacent to a parking garage, which resulted in no window opportunities on a 50-foot-tall wall of the lobby interior. The task was to create a dynamic lighting approach for the wall that would create visual interest. LED technology, according to Hennes, was the solution to the problem as the total space in the wall cavity was about 6 inches and not many other lighting methods would have worked. White 0.12W LEDs are mounted on the wall in the lobby with a diffusing layer of glass in front of them. A similar idea is employed in the elevator cabs, where LEDs are embedded between glass layers, “creating a sandwich that would create texture and a pattern so the grid would have sparkle,” Hennes explains, adding that using LEDs inside “gave us the opportunity to establish a design concept for the exterior façade and carry it into the lobby and through to the elevators.”

Illuminating the Cira Centre so that its architectural form is unified day and night was no easy task, but the lighting design accomplishes what CBBLD set out to do—to create a memorable lighting scheme. “The LEDs are the element that draw your eye and are really what you will remember about the building,” Hennes says. LED technology successfully is used to help draw attention to the glass tower, making its presence visible amid the Philadelphia skyline.

PROJECT | Cira Centre, Philadelphia

DESIGN TEAM | Cline Bettridge Bernstein Lighting Design, New York City (lighting designer); Pelli Clarke Pelli Architects, New Haven, Connecticut (design architect); Bower Lewis Thrower Architects, Philadelphia (architect of record)

PHOTOGRAPHERS | ESTO (below right); Robert Bradley Maule (facing page and below left)

PROJECT SIZE | 727,725 square feet

MANUFACTURERS | Bartco Lighting, Bega, Belfer, Color Kinetics, Designplan Lighting, Elliptipar, Hydrel, Kurt Versen, LED Effects, LED Inc., Litelab, RSA Lighting, TIR Systems, Zumtobel Lighting