© Paul Warchol

GHT worked closely with RTKL, AtSite, and Forrester Construction to complete a building retrofit and interior fit-out for the American Society of Hematology (ASH), the building owner and primary tenant of 2021 L Street NW. Existing base building systems were upgraded to meet LEED certification goals. Split system DX units were replaced with a high efficiency water source heat pump system with cooling tower, and a high efficiency boiler was installed to condition the building. Conditioned air is delivered via thermally powered variable air volume (VAV) diffusers, which also provide individual temperature control to every enclosed office.

GHT designed the ductwork to maximize the ceiling heights in tenant spaces, a typical challenge posed by Washington, DC’s building height restrictions.  The construction of an internal stairway further emphasized the importance of proper ductwork design, as the structure necessary to support it conflicts with a typical duct layout.  Duct branches were split into an abnormally high number of smaller branches while maintaining proper flow and decreasing pressure loss.  The stairwell is protected with innovative smoke curtains and lit using high efficiency light fixtures in conjunction with natural daylight from the adjacent façade.

The project achieved a certification level of Platinum under the LEED for New Construction™ rating system. Additional sustainable features include low-flow plumbing fixtures in all core rest rooms; water efficient showerheads in fitness center locker/changing rooms; extensive thermal and lighting controls; and daylight harvesting.