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I t is a classic case of actions speaking louder than words. As one of the nation’s leading organizations that supports environmentally responsible building and the founder of the LEED Green Building Rating System, it was critical that the U.S. Green Building Council “walk the walk” when it renovated its not-so-green headquarters in downtown Washington, D.C. And what better way for the USGBC to do so than to have a space that achieves the ultimate rating in a system it champions itself.
The newly renovated headquarters is LEED Platinum-certified for Commercial Interiors, with energy use 35 percent below the LEED-prescribed level of ASHRAE/IESNA 90.1-2004. As icing on the cake, the renovation project is located within a building that is Gold-rated LEED for New Construction.
There was nothing particularly green about the existing USGBC headquarters. It was located on a single floor within a tenanted building and needed to be expanded to fit a growing number of staff. To make the 22,000-sq ft space the pre-eminent showcase for the USGBC, interior architects Perkins + Will made sure that from floor to ceiling, every aspect of the new space demonstrated the organization’s commitment to forward thinking and innovation, while helping to further the Council’s goal of demonstrating that green building concepts can be adapted to virtually any building type or space. Between reclaimed materials, low-flow faucets, Energy Star equipment, low-chemical emission materials and other green measures, the new space is an ideal case study for sustainable design.
And then there is the lighting. Designed by Brian Mosbacher and Steven Bliss (Bliss Fasman Lighting Design, New York, NY), the lighting helped seal the deal in terms of its LEED rating. Of the space’s 45 LEED points, five are attributable to lighting energy and usage: three points for optimizing energy performance-lighting power; one point for optimizing energy performance-lighting controls; and one point for controllability of systems-lighting.
The goal for Mosbacher and Bliss was to have the highest perceived light levels while minimizing the connected load to meet LEED requirements. The project came in at a mere 0.65 watts per sq ft. “The lighting concepts were to create a modern, clean office environment and best meet the specific needs for each particular space,” says Mosbacher. “The major challenge was to provide enough light, or perceived brightness levels, for a comfortable work environment,” he says.
The renovation included open and private office areas, conference rooms, corridors, a lobby and a lunch area. The open office areas have low-height workstations which allow daylight to flow into the entire space, to every employee, so that there isn’t heavy reliance on electric lighting. Enclosed offices are located around the core while low-height workstations are located with direct access to operable perimeter windows. All common spaces are centrally located providing opportunity for impromptu collaboration between departments. Spaces are multi-functional: offices serve as conference rooms, the library/pantry as meeting space and conference rooms as workrooms.
OFFICE SPACE
A variety of sources appear throughout the headquarters—fluorescent, ceramic metal halide, fiber optics, LED—and all have one thing in common: they are long-life lamp types, which speaks to the spirit of the USGBC. (Incandescent is out of the picture. Not a single one was used throughout the space.) Lighting products donated by manufacturers such as OSRAM SYLVANIA and Cooper Lighting Industries were selected for high efficiency and low energy use. “A major challenge for us was to find fixtures of high efficiency that were able to provide 30 footcandles on the work plane while consuming minimal wattage,” says Bliss.
One of the challenges designers faced in integrating lighting with the architecture was the space’s relatively low ceiling heights—just 9 ft between floors, minus 1 ft for ceiling space. “The open office area was originally going to have an open ceiling design to maximize the height of the space. Later, this changed to a dropped ceiling condition. In the end, we like the result, which was lower ceiling heights, but higher reflectance, which added a smooth texture as compared to the existing concrete ceiling,” explains Mosbacher.
 Starting in the reception area, fiber-optic fixtures integrated within a wall slot cove accentuate a natural timber wall. Recessed linear slot lights and recessed downlights delineate the clean lines of the architecture. In the nearby corridors and elevator lobby, staggered slot fixtures randomly placed in the ceiling add brightness to the ceiling plane and provide a fun rhythm and flow to the space. Here, as well as in lobbies and reception areas, FO40/830/XP lamps (from OSRAM) were installed with an anticipated lifespan of 30,000 hours.
 In the open office areas, large windows allow plenty of infiltration of natural daylight, which works with the controls harvesting system. All of the indirect lighting fixtures in this area are individually controlled to respond to changing daylight conditions within the space. In areas where daylight does not penetrate, interior walls are lighted with perimeter fixtures. A daylight harvesting dimming ballast (from Just Right Light) continuously monitors the available daylight at each fixture location to supply only the minimum amount of electric light needed for ambient light levels. The rest of the areas utilize a preset control system (from Lutron).
The open office work and conference spaces are lighted with 32-W T8 fluorescent lamps, operating on programmed start ballasts. The linear fluorescents are supplemented with 18-W pin-base amalgam compact fluorescent lamps in downlighting fixtures. “Generally speaking, we prefer T5 fixture designs because of the smaller fixture profile sizes and their improved efficiency. However, we found that ballasts for T8 lamps have been further engineered than T5 ballasts, simply because they have been in development for a longer period of time,” explains Bliss. The low power consumption ballasts for T8 lamps actually consume less energy than T5 lamps, even though the nominal lamp wattages are less. “In time, we expect the T5 ballast technologies to improve to come up to speed with T8 technologies, but for this project we did pursue T8 lamps due to the lower power draw ballast technologies,” he adds.
Also in the open office area, decorative pendants (from Shaper, Cooper) provide a visual source to give the impression of brightness and add to the feeling of a lighted space. Individual LED task lights allow employees to control the amount of light within their work area while consuming little power. Indirect/direct lighting (from Neo-Ray, Cooper) improves the perception of brightness and provides base illumination levels.
In the private office areas, direct/indirect recessed lights (from Neo-Ray, Cooper) were chosen. “These fixtures light higher on the walls as compared to a parabolic fixture which would cut off light,” explains Mosbacher. This effect accentuates the perception of brightness while providing relatively low light levels. In addition, T8 fluorescent lamps (from OSRAM) were used
Moving into the enclosed conference rooms, staggered rough-hewn wood timbers recycled from another project add warmth and allow vistas through the slots into the open office areas. The wood is accented with downlight wall washers, while a 6-ft-diameter dome fixture mimics the effect from a natural diffuse skylight. Finally, in the multi-function lunchroom which also serves as a library, workspace and recycling center, the lighting strategy included T5 fluorescent lamps. Mosbacher says the biggest hurdle was creating a design to meet the connected loads, calculation and light levels—all while achieving the goals of both the architect and the client. The result is that now the USGBC has a space that clearly communicates its mission and proof that the ideals of green building provide real benefits—not to mention lower energy costs. That’s quite a way to lead with LEED.
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