Firm name: GHT Limited
Project building name and location: American Society of Hematology (ASH), Washington D.C.
Type of building and type of project: Office Building, Retrofit
Project completion date and project duration: 2010
Engineering challenges and solutions:
The project began as a tenant fit-out, but as planning progressed, the team realized that several existing systems needed to be replaced in order to meet the clients goals related to LEED certification. In addition the client decided to cut a new internal open stairway connecting the 6th to 10th floor.
The base building had been originally outfitted with spit system DX units. Those were removed and replaced with a high efficiency water source heat pump system with cooling tower and a high efficiency boiler was installed to condition the building. The conditioned air is delivered throughout the space via numerous thermally powered variable air volume (VAV) diffusers, which also provided individual temperature control to every enclosed office. The team’s mechanical designers also designed the ductwork to maximize the possible ceiling heights in the tenant areas where possible, which is a regular challenge in Washington, DC.
The construction of the internal stairway further emphasized the importance of proper ductwork design, as the structure necessary to support it was in direct conflict with a typical duct layout. Duct branches needed to be split into an abnormally high number of smaller branches while still maintaining proper flow and decreasing pressure loss. The stairwell was protected with innovative smoke curtains and lit using high efficiency light fixtures in conjunction with natural daylight from the adjacent façade.