Washington Dulles International Airport, Z-Gates Concourse, Dulles, VA

To better serve regional aircraft at Washington Dulles International Airport, the Metropolitan Washington Airport Authority (MWAA) embarked on an effort to replace outdated gates with permanent “Z”-gates. With architectural firm Giuliana Associates, Syska was contracted to design Phase I, encompassing five gates connected to the main terminal — a celebrated landmark designed by Eero Saarinen.

The East Concourse measures 500 feet long, forty feet wide, and fourteen feet high. One of biggest engineering challenges was finding space for the complex critical systems while maintaining the concourse’s architectural height and mid-century aesthetic.

A conventional ceiling-mounted ventilation system would have required dropping the ceiling to a confining eight feet. Instead, we introduced a displacement ventilation system and housed the main infrastructure utilities in a five foot high crawl space between the concourse and the baggage basement floor below. This approach allowed us to maintain the high ceilings, successfully apply displacement ventilation technology to the airport environment, and conserve energy.
Significant engineering features included:

• Displacement ventilation system: An innovative cooling and heating system that discharges supply air at a low velocity directly to room occupants through diffusers close to the ground. The fresh air reaches occupants and other heat sources with minimal containment mixing, and rising in vertical heat plumes to a return/exhaust air system mounted close to or on the ceiling.
• Occupied zone cooling: Targeting the occupied zone–ground to six feet above–for air conditioning to deliver better air quality using less energy.
• Building Management System: A direct intelligent control panel to monitor the indoor and outside air enthalpy and control volume fresh air that is drawn inside.
• Computational Fluid Dynamics analysis: Our CFD models identify the optimal layout for air diffuser placement to ensure efficient air flow, seamless passenger traffic and sufficient concourse seating.
• Electrical System: Photoelectric and occupancy controls installed in interior spaces, such as naturally lit areas and public spaces, help to conserve energy.

Completed in 2014, the Z-Gates achieved the MWAA’s vision of a permanent, beautiful and efficient space to serve the airport’s smaller wingspan jet carriers.