© Carl Cox

The Department of the Interior’s (DOI) historic headquarters has remained operational during an extensive six-phase renovation process. The entire infrastructure and interior of the 60-year-old building are being revitalized and modernized while maintaining sensitivity to the substantial historic fabric of the exterior and interior. Because the original building was one of the first federal office buildings designed to be air conditioned, the original low pressure induction system was systematically decommissioned wing-by-wing while the new HVAC system was installed, necessitating the continuous operation of two distinct HVAC systems while the phased construction continued.

The design included the construction of a new  8000KW chilled water plant, incorporation of numerous dedicated outside air systems (DOAS) – one of the first such systems in the GSA portfolio, now a GSA standard – and the integration of fan coil units into the perimeter historic induction unit cabinets.  Numerous historically significant spaces are encompassed, such as a 13,000 SF museum, major auditorium, library, cafeteria, gymnasium, and the Secretary of the Interior’s suite.

In addition to MEP engineering design for building systems, GHT completed numerous engineering studies. Our research resulted in the development of a best value systems replacement concept for the modernization of the entire infrastructure and interior. The innovative vertical systems replacement methodology has kept the project on schedule.