Sustainable building design through passive measures

An over 50% reduction in EUI was achieved first by reducing loads through passive design measures, namely a high-performance envelope whose ensemble of layers were tuned differently by façade. External overhangs and a 30’ deep, exterior curtainwall fin structure reduce peak cooling 10–18%. To prevent glare, an interior screen of vertical slats varies in density/spacing depending on programmatic requirements. The layers work together to reduce annual direct sun hours in perimeter zones by 50–70%, depending on orientation. Finally, 49 skylights with 4 different typologies, each based on different lighting phenomenon of PNW forests, daylight over 60% of the enplaning level with only a 9% SAF ratio, versus 14% of the original building.

Efficient construction and operations

The 1M SF expansion re-used existing structures, reducing embodied carbon by 56% compared to a greenfield airport. New material optimization accounts for an additional 6% reduction for a total 62% savings. Strategies included using locally and equitably sourced mass timber instead of an all-steel roof, integrating GWP limits into low-carbon concrete specs, and sourcing local steel from cleaner PNW grids. Mass plywood offcuts were also upcycled from the roof deck for the concession pavilion wall panels. For operational carbon, a steam central plant conversion to an open-loop, ground-source heat pump cuts over 40% of emissions on day one, while the electrification of space and water heating will accelerate decarbonisation as the grid gets cleaner over time.

Landscape & Biodiversity Integration

This project viewed biodiversity integration at the regional landscape scale. The team designed PDX’s mass timber roof and its sourcing strategy to steward the PNW’s most precious natural and cultural resource – its forests. Sustainable sourcing criteria required FSC-certified wood or innovative, transparency-based procurement to intentionally source wood from ecological forestry practices above and beyond local regulations. 73% of the roof’s 3M board feet met these criteria and 25% came from best-in-class forest restoration maximising biodiversity and wildfire resistance in the region’s dry forests. 1M board feet can be traced back to forest of origin, effectively reconnecting the project back to the land and communities from which it grew.

Land use & Transformation

Regenerative land use and transformation for PDX was more about what it didn’t do in order to grow from serving 20 million annual passengers to 35 million. Instead of building a new terminal somewhere else with fewer constraints, the decision was made to expand the existing terminal in situ, but with the added requirement of doing it without disrupting any airport operations during construction. PDX proved this was possible through strategic on-site prefabrication of the roof and a modular approach to erection. While this was the more sustainable move from an embodied carbon standpoint, it also serves as a model for how to renovate other large airports in the US, many of which need similar scales of infrastructure upgrades.

Participatory Design

The community group Access PDX was engaged to go beyond universal design principles to support and elevate the experience of physically disabled user groups. The team conducted workshops for each major space to gather feedback on the size and location of wayfinding, lighting needs, longest distances between respite for mobility-impaired groups, and configuration of ticket counter curbs. The design team also worked closely with the Regional Arts & Culture Council to invite artists to co-create permanent public art that reflects the diversity of communities the Port of Portland serves. The art program embedded its values of inclusion through intentional outreach to marginalised communities and a selection process that favoured equitable outcomes.

Community Impact and Resilience

PDX has always been a destination airport for its local community, and the new terminal continues to build on this legacy with a higher-than-typical ratio of pre-security retail and food options (30%) and an emphasis on publicly accessible gathering spaces that redefine an airport as civic architecture and infrastructure for the community. From a resilience standpoint, PDX plays a crucial role in supporting community health during times of emergency, namely the forthcoming Cascadia Subduction Zone earthquake. Seismic criteria required the structure to be able to withstand a 9.0 magnitude earthquake and 2 feet of lateral roof movement while still being able to function as an airport to support the city’s recovery effort.

Financial Feasibility

The biggest economic challenge was intensively renovating an existing airport without impacting flight traffic. Prefabricating the entire roof on site helped make this possible, which allowed for construction lower to the ground, concurrent MEP systems integration, and parallel demolition work. The roof modules could then be transported and launched into place quickly after active airport hours to avoid disruption. To ensure a long-term, equitable economic impact, PDX set a goal for emerging, small, or minority- and women-owned firms to account for 22–25% of design fee soft costs. Hard construction costs also preferred this criteria, and over $290,000,000 of construction contracts went to this type of business, roughly 17% of the total.

Aesthetic Qualities and Cultural Integration

Designed to evoke the feeling of a walk in the forest, the new main terminal transcends functionality and aspires to revere the natural beauty and awe of Oregon’s landscape. The undulating 9-acre mass timber roof and its local, sustainable, and equitable sourcing approach blueprint a new future for the forest product industry in Oregon and across North America. Portland’s small, walkable city blocks informed the design of the concessions’ storefronts and their retail “streetscapes.” More than 70 trees and 5,000 plants provide a sense of wandering and serve as biophilic wayfinding throughout. These approaches coalesce to root this project in place through both its supply chain ethics and reverence for the region’s urban and ecological interface.