SeaTac Low Voltage
SeaTac Airport Main Terminal Low Voltage Systems Upgrade / SeatacWA
What preconstruction planning is needed for updating electrical systems in one of the busiest airports in the country?

Valued just under $80 million, the SeaTac Main Terminal Low Voltage Upgrade project is a comprehensive initiative designed to modernize and replace the aging electrical infrastructure at SeaTac’s main terminal, which traces its origins back to the airport’s original construction in 1949. The project’s complexity is heightened by the busy airport environment, requiring intricate tasks such as replacing power entrance switchgear, upgrading numerous service panels and their feeders, constructing new electrical rooms, and making substantial modifications to existing ones.

Mortenson’s collaborative effort with Casne Engineering involves a detailed three-year pre-construction period. During this extended planning phase, Mortenson addresses various aspects of the project, including advising the design team, securing space for new equipment and rooms, implementing circuit tracing for accurate drawings, and coordinating with tenants and airport management to determine construction phasing.

Mortenson’s project team utilizes three-dimensional (3D) scans of congested areas to create precise construction models. This technology-driven approach aims to minimize disruptions for airport tenants and visitors. Given the extensive nature of the Main Terminal Low Voltage Upgrade project, which necessitates over 2,100 power shutdowns, Mortenson places a strong emphasis on proactive communication to avoid surprises for airport operations and passengers. The collaborative efforts of all stakeholders, including the owner, are orchestrated in a carefully sequenced and well-communicated manner.

Moreover, Mortenson employs Target Value Delivery (TVD) as a comprehensive management practice throughout the design and construction phases. This approach allows the project budget to be dissected into smaller, manageable components, facilitating a more detailed analysis of potential savings opportunities and risks of overruns. The TVD program also instills a sense of ownership within the working team, fostering accountability. Management practices related to Target Value Delivery (TVD) have led to a noteworthy five percent decrease in the ultimate contract price, presenting a positive surprise for the client and a commendable accomplishment considering current market conditions.

Facts And Figures

Port of Seattle


Delivery Methods


The Team