UNLIKE THE CLASSICAL-COLUMNED STRUCTURES
for which Washington, D.C., is known, the late-20th-century federal buildings that dominate the city’s southwestern quadrant tend to be graceless and hulking. One of these behemoth structures, however, is getting a major facelift—and a groundbreaking, sustainable airflow system in the process.
Designed by modernist Edward Durell Stone, the 10-story building originally was occupied in 1970 by the Washington-based U.S. Department of Transportation. Spanning one entire city block, the building had been clad in a heavy white marble that was leavened only by skinny columns of windows. The building had problems from the beginning, including a lack of energy efficiency and a nearly constant need to replace failing marble. Furthermore, floor-to-ceiling heights were lower than in other buildings, which contributed to the dark and unwelcoming feel of the interior.
Last summer, however, work began on a complete redevelopment of the building, now called the Constitution Center. Led by the Washington office of SmithGroup, a national architecture and engineering firm, and David Nassif Associates, a Boston-based building owner, the redevelopment will convert the building into a 1.4-million-square
foot (130060-m2) commercial facility, along with 15 acres (6 hectares) of underground parking, constituting the largest private-sector office building and underground garage in the city. Because of the reuse of the building’s structure and other measures, the project is expected to achieve a Silver rating under the Washington-based U.S. Green Building Council's LEED for Core and Shell rating system.
“The owners saw this project as a unique opportunity to completely renovate the building and bring it up to modern standards,” says David Varner, AIA, LEED AP, principal in charge with SmithGroup. “Leaving the structure in place was an early sustainable decision.”
The new exterior of Constitution Center will transform the heavy stonework of the original façade into a lighter, more transparent design. By sheathing the exterior in a glass curtainwall, the design team hopes to maximize the site’s
tremendous city views and greatly increase daylighting of office spaces. The curtainwall also will meet federal security criteria for blast resistance through the use of deep mullions, composite structure and various thicknesses of laminated insulating glass.
CHILLED BEAM / Constitution Center will feature one of the largest installations of a chilled-beam system for HVAC in the U.S. to date. Used for years in European buildings, chilled beams are an integrated water-source heating-and-cooling system mounted near or within the ceiling, wherein the beams act as the air delivery device and temperature control system. According to Varner, the system allows for higher ceilings, uses less equipment, reduces energy consumption and operates more quietly than conventional variable-air-volume systems.
Among other benefits, chilled beams can be routed and relocated relatively easily; can act independently of one another; and use less ductwork. The technology is more energy efficient than most VAV systems because heating or cooling duty is shared with the hydronic system, resulting in less central air supply and therefore less energy needed for fans. The system requires less routine upkeep, as well, with fewer central fan-powered air-handling units to maintain. During a recent test of thetechnology at the ConstitutionCenter, the chilled-beamsystem was so quietobservers did not realize the beams had been activated.
“This building had a very limited floor-to-floor height, so it was significant to reduce the ductwork needed for air circulation,” says Robert Fagg, P.E., LEED AP, director of engineering with SmithGroup’s Washington office. “The beams are very simple in design and installation. They are very energy efficient and provide a uniform temperature and minimization of drafts. From a user comfort level, the chilled beams offer a tremendous advantage.”
Computer modeling has projected a 23 percent energy savings in the Constitution Center compared with similar-sized office buildings using a standard VAV system, Fagg adds.
HOPE AND VISION / Other sustainable measures planned for the Constitution Center include recycling at least 50 percent of demolition debris, installing low-flow and -VOC materials, and increasing the vegetation at the site. Designed by the Washington-based landscape architecture firm Oculus, the all-concrete courtyard will be transformed into a lush 1-acre (0.4-hectare) garden that will help provide some much-needed storm-water retention for the massive site.
SmithGroup and Nassif Associates have partnered with Kramer Consulting, a Washington-based real-estate consulting firm, and Rockville, Md.-based James G. Davis Construction Corp. to plan for and construct the project, respectively. Construction began last July and is expected to be completed in 2009.
“There was a lot of hope and vision in the 1960s for this part of this city that never really matured,” Varner says. “Now it’s starting to happen. This building is connected to the Metro [public transit system] and many community services. It’s in a growing part of the city.”
>>KIM A. O’CONNELL writes about sustainable design from Arlington, Va.
WASHINGTON, D.C. PROJECTED COMPLETION DATE: 2009
OWNER / David Nassif Associates, Washington, (202) 484-4000 ARCHITECT AND ENGINEER / SmithGroup, Washington, www.smithgroup.com LANDSCAPE ARCHITECT / Oculus, Washington, oculus-dc.com REAL ESTATE CONSULTING / Kramer Consulting, Washington, www.kramerconsultingpc.com CONTRACTOR / James G. Davis Construction Corp., Rockville, Md., www.davisconstruction.com CHILLED-BEAM SYSTEM / TROX, Neukirchen-Vluyn, Germany, www.troxtechnik.com
TROX USA, Alpharetta, Ga., www.troxusa.com FLAKTWOODS, Zurich, Switzerland, www.flaktwoods.com DADANCO, Wyalusing, Pa., www.dadanco.com REPORT FROM THE 2007 CHILLED BEAM SYMPOSIUM FEATURING CONSTITUTION CENTER, www.troxusa.com/usa/download/ pdf/produktePdf/air_water_systems/cbs.pdf