When the Washington, D.C.-based U.S. Green Building Council (USGBC), creator of LEED, outgrew its existing workplace and needed to move into a larger home, one of the organization’s primary goals was that its new offices serve as a showcase for sustainable design principles. The USGBC’s new offices in the Service Employees Intl. Union building on Dupont Circle in Washington, D.C., designed by Perkins+Will and completed in 2007, provide proof that the organization walks its talk in regard to prescribing productive, efficient, and sustainable work environments.
The 22,000-square-foot fit-out, completed for $1.5 million (excluding donated equipment), or $95 per square foot, earned a LEED for Commercial Interiors (LEED-CI) Platinum rating in a building that has already earned LEED for New Construction (LEED-NC) Gold.
Furniture was reused from the previous office, recycled materials are common, the ceiling and carpet tiles are recyclable, the water fixtures use 40-percent less water, the paints are non-toxic, and the building is located with convenient access to mass transit – just to name a few of its green features.
Achieving LEED Platinum is no simple task, particularly when it came to the lighting, which led Perkins+Will into a collaboration with Bliss Fasman Inc., a lighting design firm based in New York City. “From a design perspective, the client wanted [its] space to be a showcase for a variety of energy-efficient lighting technologies and green-building strategies,” says Steven Bliss, principal at Bliss Fasman. “From a technical perspective, our directive from the onset of the project was to achieve the highest level of LEED certification.”
The biggest challenge was providing sufficient light levels and an appropriate perception of brightness while going 35-percent beyond the stringent lighting power limits imposed by ASHRAE Standard 90.1-2004, the model energy code. This translated to maintained light levels of 30 footcandles on the desktops for just 0.65 watts per square foot.
Bliss and Associate Lighting Designer Brian Mosbacher made an immediate decision upfront not to sacrifice lighting quality for watts. “It’s possible to achieve LEED Platinum certification and create a quality lighting design that accentuates the architecture and provides a productive and inviting environment to the end-users,” Bliss says. “We hope our project demonstrates that.”
Every lighting design starts with a need; in this case, despite the strong prioritization of efficiency and sustainability, the lighting designers resolved that the architectural and interior design needs, as defined by Perkins+Will, would drive the design – not LEED requirements. While LEED certification was part of the end game, they wanted to treat LEED as a guide to the design, not a blueprint for it.
During the process, Bliss and Mosbacher held onto two guiding philosophies. First, Mosbacher points out, accomplishing a high level of LEED with lighting begins with an in-depth understanding of the architectural design, and close collaboration among the design team. “Never count watts until the design is hatched,” he says. “Before establishing the technical lighting design concepts, we must first have an in-depth understanding of the architecture and interior finishes. In any LEED project, light colors and reflective architectural finishes are critical to maximizing light interreflections and to increase the perception of brightness.” Second, he adds, “Every watt of lighting needs to be accounted for.”
Every project, he points out, includes spaces critical to the design’s flavor and spirit, and other, more utilitarian spaces, where lighting solutions are typical and repetitive. “In the latter type of space,” says Mosbacher, “the biggest bang for the buck is possible to reduce lighting energy consumption. It’s critical to define which areas fit into these categories at the beginning of the project.”
The Lighting Design
The offices consist of private and open office spaces connected to central common areas, designed to promote collaboration. All of the spaces function as offices and meeting spaces – even the kitchen and library.
Bliss Fasman’s design supported LEED certification specifically by achieving a lower lighting power density than prescribed for office buildings by ASHRAE Standard 90.1-2004, ensuring that a majority of occupants received access to daylight and views, and providing task lighting to occupants to enable them to control their light levels.
It was immediately acknowledged by the designers that well-controlled daylight would be a useful ally, particularly in the open office area, to accelerate energy savings while increasing the perception of brightness and satisfying the occupants with daylight and views. In the open office area, large windows allow ample daylight to enter the space and provide a sense of connection with the outdoors for nine out of 10 of the occupants. Each of the lighting fixtures in the offices was configured to be individually controlled via a photosensor, enabling light output to be dimmed in response to changing light levels.
The electric lighting was designed to minimize light levels, but enhance perception of brightness by illuminating vertical surfaces, such as walls. Wattage was minimized via selection of highly efficient lamps, ballasts, and lighting fixtures. “Based on our experience on dozens of corporate interiors projects, we have found that the LEED lighting requirements can only be achieved if the following equipment is used: fluorescent fixtures with a minimum efficiency of 85 percent, energy-efficient T8 lamps, and high-performance electronic T8 ballasts,” says Bliss.
“We point out that, generally speaking, our office prefers T5 fixture designs because of the smaller profiles and improved efficiency,” Mosbacher says. “We find that ballasts for T8 lamps have been further engineered than T5 ballasts, however, simply because they have been in development for a longer period of time.”
Even though T5 lamp wattages are nominally lower than comparable T8 lamps, T8 systems powered by low-wattage T8 ballasts save more energy than comparable T5 systems, he adds. “In time, we expect T5 ballast technologies to improve, and to come up to speed with T8 technologies,” Mosbacher says.
Pendant-mount direct/indirect fixtures were specified for the open office area to accentuate the openness of the volume and provide diffuse reflected ambient illumination. These decorative, luminous fixtures provide a visual source of light and increase the general perception of brightness. The distribution of the fixtures simulates the appearance of ambient daylight during times of the day when there is less daylight entering the space. Occupants can control light levels using LED task lights.
In private offices where dropped acoustical tile ceilings are common, recessed direct/indirect fixtures are used as complementary fixtures to the design motif established in the open offices. “Recessed direct/indirect fixtures distribute light uniformly throughout the office spaces and have the effect of illuminating the perimeter wall due to their wide optical distribution,” Mosbacher says. “This vertical illumination again creates an increased perception of brightness in the enclosed office spaces.”
Meanwhile, staggered and randomly placed ceiling slot fixtures add visual interest to public spaces using an otherwise utilitarian fixture, while fiber-optic fixtures and downlights/wallwashers are used to accentuate key architectural design features, such as a natural timber wall in the reception area, and rough-hewn wood timbers, recycled from another project, in the conference rooms.
Complicating the project was the fact that the majority of the installed lighting equipment was donated by manufacturers – with the donations confirmed at different stages of the design process. This required the lighting team to rework their original designs to incorporate new products, turning the design into a moving target. “We needed to be able to quickly adapt the lighting scheme and fixture, lamp, and ballast selections to absorb the donated products that were being offered,” Bliss says.
In the end, more than 30 fixture types – using T8 fluorescent, compact fluorescent, LED, and fiber-optic light sources – were used. Lighting equipment was donated by Cooper Lighting and OSRAM Sylvania; other organizations donating time and materials to the facility included Armstrong World Industries, Benjamin Moore & Co., Formica Corp., Haworth, James G. Davis Construction Corp., Perkins+Will, and others.
A Showcase for Lighting Efficiency
In the end, the lighting of the USGBC’s new headquarters provides a showcase of energy-efficient lighting design achievable within the stringent requirements of the LEED rating system. In part because of the marriage of quality lighting design and highly efficient lighting products, the USGBC has gained a space that provides a clear understanding of its mission, and proof that the ideals of green construction provide real benefits.
Craig DiLouie (firstname.lastname@example.org), a lighting industry journalist, analyst, and marketing consultant, is principal at ZING Communications Inc., Calgary, AB.
Project: U.S. Green Building Council Headquarters
Location: Washington, D.C.
Project Adviser: URA
MEP Engineer: Stantec
Lighting Designer: Bliss Fasman Lighting Design (Steven Bliss, Brian Mosbacher)
Contractor: James G. Davis Construction Corp.
LEED Documentation: Greenlight Strategies
Commissioning Agent: Advanced Building Performance Inc.
Lighting Manufacturers: Cooper Lighting, Corelite, Halo Lighting, io Lighting, Just Right Light, Lutron Electronics Co., Mark Lighting, Metalux Lighitng, Neo-Ray, OSRAM Sylvania, Portfolio Lighting, RSA, Shaper Lighting