A Visit to the World’s Greenest Office Building
05/29/2013 § Leave a comment
By Bill Brown, Director of IU Office of Sustainability
The International Living Futures unConference in Seattle last week allowed attendees to learn more about the leading edge of sustainable design that aspires to design “living buildings” that make more energy and water than they use, while also achieving 18 other seemingly impossible “imperatives.” The Living Building Challenge has attracted over 140 registered projects around the world and a four have already met the challenge.
One of the contenders is the greenest office building in the world, The Bullitt Center, a 52,000-square-foot, six-story office building in Seattle that I was fortunate to visit after attending the conference. Denis Hayes, president of the Bullitt Foundation, was the director of the first Earth Day in 1970.
The most distinctive element of the Bullitt Center is its dramatically cantilevered perforated canopy of solar panels that mimics the tree canopy of the nearby pocket park. It is no small trick to power a six-story office building with solar photovoltaic panels in cloudy Seattle and the size of the canopy makes that clear. One would assume that getting enough precipitation to achieve all the water requirements for the building would not be difficult in Seattle, but Bloomington receives more annual rainfall than Seattle, so the canopy also helps collect rainwater.
The larger issue is getting code approval to use rainwater for something beyond toilet flushing, let alone to use for drinking water. According to the Challenge: “one hundred percent of the project’s water needs must be supplied by captured precipitation or other natural closed loop water systems that account for downstream ecosystem impacts, or by re-cycling used project water. Water must be appropriately purified without the use of chemicals.” A 56,000-gallon cistern in the basement collects rainwater for reuse. To reduce water use, the Bullitt Center utilizes a unique 6-story, foam-flush, composting toilet system, with all the composting systems in the basement mechanical room.
This building is designed to accommodate current and future codes. When code allows the Bullitt Center to filter its own potable water, possibly through designation as its own water district, it can turn a few valves and do so. Until then, it can remain attached to city water and sewer systems, while demonstrating the state of the art in other areas of building design.
Like most buildings in Seattle, air conditioning is not required but for a few days per year. A ground-source heat pump system with 26 400-foot-deep bore holes provides radiant heating and can also provide radiant cooling for hot days with low humidity.
The building’s structure is a locally sourced timber frame with massive glulam beams. Floor-to-ceiling windows are state-of-the-art, argon-filled, triple-pane glazing that help the building achieve 80% better energy performance than typical buildings. The windows and shades are automatically controlled with manual override. No workstation is more than 30 feet from an operable window and daylight.
Not included are 16 chemicals on the Living Building Red List for toxic chemicals. This list is challenging in that chemicals like polyvinyl chloride (PVC), formaldehyde, and halogenated flame retardants are on the Red List, but also ubiquitous in the world of building materials.
The Bullitt Center was constructed for $18.5 million, which is 20% higher than Seattle market rate for class A office space. Free electricity and water is included in the $28-$30 per square foot per year lease rate, along with the health and productivity benefits already associated with green buildings. Open since Earth Day, lease spaces are filling rapidly.
One of the 20 imperatives for The Living Building Challenge is beauty and the tour convinced me this was accomplished inside and out with a design informed by function, materials, people, views, nature, and site. Miller-Hull Partnership, a Seattle firm, led the integrated design team.
In order to be certified as a living building, the Bullitt Center will have to operate fully occupied for a full year to prove the performance of its systems. Stay tuned.