Washington Headquarters Services
Located in Alexandria, Virginia, Washington Headquarters Services is a federal agency building that provides operational and maintenance support to various government bodies in the National Capital Region and beyond. The facility houses the 37 Department of Defense agencies and consolidates approximately 6,400 employees.
Spanning almost two million square feet, Southland Engineering provided full MEP and building automation designs. The 16-acre campus includes a 15 and 17-story Class A office tower, on top of a common area with kitchen, cafeteria, fitness center, health clinic, bank, mission critical space, auditorium, and conference center. The campus also features two parking garages and remote inspection and delivery facilities.
Approach & Innovations
To comply with federally mandated and LEED Gold energy requirements, Southland Engineering designed a 6,250-ton variable chilled water system that supplies dual chilled water temperatures, combined with a singular condenser water system. By decoupling the sensible and latent loads at the chiller plant, 42-degree water is supplied to the four dedicated outside air units for the building and other high latent loads. The sensible loop is utilized for the facility’s IT, technical loads, and office floors. Decoupling the loads allowed the design team to select a much more efficient chiller for the sensible cooling, as well as maximize the water side economizer hours utilized throughout the year to save significant energy.
Due to the critical nature of the facility, Southland provided a completely independent air-cooled chiller system with 100% redundant pathways and coils in the IT and critical systems. By collaborating with the structural engineer and architect, the design team was able to efficiently arrange the IT rooms to eliminate significant piping and invest the savings into a completely redundant system.
The facility featured many electrical and technical spaces within the tower that do not allow other systems to be routed throughout the space. To overcome this challenge, Southland Engineering designed a siphonic storm system, allowing the piping to be designed flat, smaller, and using fewer risers.
As part of the owner’s requirement for floors to have a flexible system for possible tenant renovations, Southland Engineering designed fan-powered induction units which utilize dedicated outside air with a flow ring. This allows building managers to look easily at the amount of outside air being supplied to the space. This strategy reduces the duct size by limiting recirculation of return air to the air handlers and provides additional plenum space for other systems. To provide even further flexibility, the design team standardized the duct and piping for tenant floors to provide the owner the ability to easily add or reconfigure zones.