Green by Design

In July, the first phase of a new full-service healthcare campus (the first hospital built from the ground up in 25 years in King County, Washington) opened its doors to the public. The campus was designed with two key challenges in mind: to create an architectural design that aligned with patient and community needs and to create medical buildings that significantly cut energy usage across the new campus.

The design team at CollinsWoerman succeeded on both accounts: The Swedish/Issaquah medical center campus located in Issaquah, Washington, is now considered the most energy-efficient medical campus in the region—and possibly the nation—and the project has been embraced by the community.

Focusing on sustainability

Hospitals spend more on energy per square foot than any other commercial building type, according to the American Society of Heating Refrigerating and Air Conditioning Engineers. Hospitals have unique and intensive energy use requirements, such as the need for lighting and heating 24 hours a day, and significant energy consumption used by ventilation systems, sterilization of tools, laundry, food preparation, and use of other medical equipment. Energy savings not only improves overall sustainability and environmental impact, but has the potential to dramatically lower a hospital’s bottom line.

Using guidance from the AIA 2030 Commitment, the hospital set an aggressive, low-energy usage goal of achieving an EUI of 150 kBtu/sf/yr. Mechanical system performance at 150 kBTU/sf/yr (equivalent of the power needed for 2,200 midsized American homes per year) is 43% less than a typical hospital in the northwest and would place this hospital in the top tier of energy-efficient hospitals in both the region and the nation. 

Additionally, the hospital planned to achieve an ENERGY STAR rating of 75 or higher at completion and one year after occupancy (on the rating system’s 1–100 scale, a rating of 50 indicates average energy performance, while a rating of 75 or better indicates top performance). Compared to peers nationwide, buildings that perform in the top 25% consume about 35% less energy on average than typical structures. Data relevant to achieving this merit will be tracked in the initial year of operation. At this point, an estimated score of 90 is anticipated.

Planning the design

Early in the design process, the project team participated in design meetings to gather ideas for how to achieve the project’s sustainability and energy efficiency goals. The use of building energy simulation software determined which efficiency measures would be most useful to meet the project goals. 

Through this process, it was determined to orient the hospital to get sun on three sides with a basement area that receives daylight—a benefit for staff and patients. Research has shown that the human body best recovers from illness in environments that include an abundance of natural lighting, so this layout was ideal. In addition, high-performance glazing in energy-efficient frames and the use of exterior/interior shading devices result in less artificial lighting and energy consumption.

Achievement of these energy goals requires special features and systems for the architectural, mechanical, and electrical components of the building, but also significant consideration for the site and the facility’s greater impact in the community.

Creating the site

This new facility was built on a previously cleared site, and no trees were removed to construct the buildings. Like all new projects, the development added some impervious area to the environment, but efforts were made to consolidate the building footprint and stack floor plates within height limitations to reduce the overall building footprint and associated impervious space. Additionally, by adding a single level of below-grade parking, the project required 50,000 square feet less impervious area. 

Similarly, substantial excavation for two floors of below-grade space placed another approximately 75,000 square feet of area beneath that footprint.