Interface Engineering overcame design challenge of incorporating new systems into old buildings
By Sam Bennett
For Interface Engineering, the White Stag Block was no run-of-the-mill renovation. Interface, which won an ACEC Grand Award for the White Stag Block project, faced the challenge of designing modern, energy-efficient systems into 117,000 square feet of space of buildings a century old.
The buildings were being redesigned to accommodate the University of Oregon’s schools of architecture and journalism.
The firm was responsible for the mechanical, electrical and plumbing design for the shell and core of the Old Town project, as well as for tenant improvements.
Interface began the project with three neglected buildings adjacent to each other, with varied floor-to-ceiling heights. Aiming for Leadership and Energy and Environmental Design gold certification, Interface had to design a way to provide a rainwater retention tank as well as a storm water retention tank. Interface proposed that the storm water retention tank double as rainwater harvesting storage–rather than having two tanks in the shared basement that would need to also accommodate mechanical, electrical and plumbing equipment.
Interface also had limited access to put mechanical equipment on the roof of the historic structures. The building lacked cooling equipment prior to the renovation. The roof was not designed to hold the extra weight and adding an equipment room to the roof would have been prohibitively expensive. So Interface designed the basement space to accommodate them, where the storm water and rainwater storage tanks were stored.
To avoid making costly seismic upgrades, the air handling systems and new transformers (required because of an overloaded, outdated power grid) had to be placed in the basement.
Within the buildings, the mechanical systems were designed to be exposed and work around historic pillars in the building. Ductwork had to detour around such obstacles and varying heights of ceilings, and also needed to have a symmetrical look that fit with the era of the buildings. Some of the ceilings were just 8 feet high.
By making all these adjustments, the system achieved 30 percent greater efficiency than industry standards.
Adding to the complexity is that the building had to accommodate a variety of users, including classrooms, a computer lab, offices and a cafe–each with different HVAC and lighting needs. Interface managed to meet the tenants’ needs while keeping the historic integrity of the building.
Interface also served as a consultant to the building’s property managers when structuring tenant leases, and the firm assisted with creating the building management budget.
The project’s initial budget was $35 million and the final cost was $37 million. The mechanical, electrical and plumbing budget began at $5 million, and the final cost was $5.6 million.
Other issues that made design more challenging included fire damage in one of the buildings, leaking windows and low clearance in the basement.
Overall, Interface’s designers and engineers contributed 18 of the project’s 44 LEED points toward gold certification.