Sea-Tac North Satellite Expansion, Washington

Tetra Tech’s High Performance Buildings Group provided commissioning services for design phases of the renovation of the Port of Seattle’s 395,000-square-foot North Satellite (NSAT).


  • Size: 395,000 square feet
  • Construction Cost: $550 million
  • Client/Owner: Port of Seattle
  • Architect: Fentress
  • Contractor: Hensel Phelps
  • Completion Date: 2021


Our commissioning team’s expertise in testing and verifying systems in airport facilities was utilized on this project, and adds to our growing portfolio of transportation-focused work, which includes several other projects at Sea-Tac. 

Tetra Tech is assisting the Port of Seattle in updating the 45-year-old NSAT portion of Seattle’s largest airport. Facility elements include the new Alaska Airline lounge, major concourse renovations/additions, concessions, and gates. Tetra Tech is commissioning all building mechanical, electrical, and plumbing systems throughout the 395,000-square-foot space, including verification of the smoke control system, gate systems, and assisting with LEED calculations. In order to complete the required commissioning for the project, some systems will be commissioned multiple times to allow for phased construction while the terminal remains active to serve travelers.

Tetra Tech provided commissioning for the following systems:

  • Equipment, components, and systems
  • Mechanical, electrical, and plumbing design
  • Communications
  • Closed circuit television
  • Public address
  • Security including biometric screening
  • Vertical conveyance including elevators and escalators
  • Airplane fueling
  • Pre-conditioned air
  • Emergency power/generator
  • 400 Hz ground power
  • Electrical ground support power (eGSE)
  • 15kV upgrades
  • Lighting controls
  • Power monitoring and data gathering
  • Transient voltage surge
  • Suppression
  • Grounding systems
  • Airplane jet bridge
  • Loading dock

Images courtesy of the Port of Seattle