With its silvery metal panels and glass cladding, and a canted photovoltaic (PV) array that projects beyond the edges of the roof like the brim of a hat, the recently completed six-story Bullitt Center in Seattle's Capitol Hill neighborhood doesn't at all resemble a Douglas-fir forest, admits Denis Hayes. Nevertheless, Hayes, who is president and CEO of the Bullitt Foundation, is fond of comparing the 52,000-square-foot office building to just such a forest. "It functions like one," he says.
Location Seattle, Washington (Seattle Isthmus)
Gross area 52,000 ft2 (4,830 m2)
Completed April 2013
Cost $18.5 million
Annual purchased energy use (based on simulation) 0 kBtu/ft2 (0 MJ/m2), 100% reduction from base case
Annual carbon footprint (predicted) 0 lb CO2/ft2 (0 kg CO2/m2)
Program Office, classroom, seminar
TEAM & SOURCES
Windows Schüco/Goldfinch Brothers
Glazing PPG/Northwest Industries; Solarban 60
Cladding thermal spacers Cascadia Clip
Appearances aside, Hayes's metaphor is apt. If the $18.5 million building operates as intended, it will be self-sufficient in much the same way a forest is: it will obtain all its water from the rain that falls on the site, and over the course of a year will consume no more electricity than is generated by the roof's PVs.
The goals for the building, which serves as the headquarters for the environmentally focused foundation and as space for like-minded tenants, include Living Building Challenge (LBC) certification. The process is a rigorous one that entails satisfying 20 tough-to-achieve "imperatives" and requires a year's worth of post-occupancy data to demonstrate net-zero operations for energy and water. Since LBC's launch in 2006, only four buildings have achieved living-building status. Approximately 150 other projects, located all over the world, are registered with the LBC program, administered by the International Living Future Institute (ILFI).
Tenants began moving into the Bullitt earlier this year. Many, such as ILFI; the property's developer, Point32; and the building's m/e/p engineer, PAE, have some connection to the project. These organizations have sustainability in their DNA and might be willing to put up with some inconvenience for the sake of the environment. However, Hayes was determined to create a comfortable workplace. "Denis was clear that it couldn't be too much of a hippie experience," says Craig Curtis, a partner at the Miller Hull Partnership, the Bullitt's architect. "It had to be a place where people would want to be and want to work."
Toward that end, the project team devised a heavy-timber frame, with its handsome components, including laminated beams and wood-deck ceilings, left largely exposed. The designers gave the Bullitt 14-foot floor-to-floor heights and correspondingly tall, but thermally efficient glazing—a configuration that allows daylight to penetrate deep into the interior. And with the goal of making the stairs more appealing than the elevator, they created an "irresistible stair" with wood treads and glass balustrades. It is a prominent feature of the facade, providing views of the city's skyline.
The climate-control system at Bullitt depends on natural ventilation and automated, operable windows. But when it is too hot or too cold to open these windows, a heat-recovery ventilator kicks in. For space heating and cooling, a radiant floor system taps the consistent temperature of the earth via 26 geothermal wells, each 400 feet deep.
The building and these systems are designed to be extremely energy-efficient, with an energy-use intensity about 80 percent below that of an average office building. However, the margin between the power expected from the 242-kilowatt PV array and estimated demand is razor-thin—only 2 to 3 percent, say the designers. They predict that almost half the electricity will be consumed by devices like printers, computers, and appliances—the so-called plug loads over which landlords typically have little control. To keep these loads in check, each tenant has agreed to an energy allowance as part of its lease.
The limits have prompted tenants to closely monitor their operations. In preparation for its move, PAE analyzed its own electricity use. "We found we were using too much energy for the building we were designing," says the firm's president, Paul Schwer. PAE has since revamped its IT infrastructure and replaced equipment.
Realizing the project required clearing many regulatory hurdles. For example, providing enough PV panels to bring the net-zero energy goal within reach in cloudy Seattle meant an array covering 14,000 square feet, projecting as much as 20 feet beyond the building's perimeter. This extension over the public right-of-way involved a special allowance from Seattle's Department of Planning and Development.
Still under way are negotiations with the local utility and the state Department of Health to designate the building as its own water district. If granted this status, the Bullitt will use rainwater collected from the roof and stored in a 56,000-gallon basement cistern to supply showers, sinks, and water fountains—after a multistep filtering and purification process. In the meantime, the project has an exemption from ILFI allowing it to rely on the municipal utility for potable uses but still satisfy the LBC net-zero water imperative. Other water-conserving strategies include irrigation that utilizes graywater and the world's only six-story composting toilet system.
One of the most labor-intensive aspects of the project has been the vetting of building products for compliance with LBC's materials standards. These prohibit the use of 14 potentially toxic substances on the challenge's Red List—many of which, such as PVC and formaldehyde, are commonplace in building materials. The restrictions are intended to ensure a healthy environment for occupants and spur market transformation. The hope is that the requirements will encourage manufacturers to examine their supply chains.
Joe David, a project associate with Point32, estimates that he devoted a year and a half to investigating about 1,200 products. He points to several materials specified at Bullitt as proof that the LBC requirements are serving as a catalyst for change. One of the more notable examples is the wall assembly's fluid-applied air-and-weather barrier. Although it was an essential part of the high-performance building envelope, David's research determined that the barrier contained phthalates, a Red Listed family of chemicals often added to plastics to increase their flexibility. In response to the project team's queries, the barrier's manufacturer, Prosoco, reformulated the product to eliminate the phthalates.
It will be some time before the Bullitt has sufficient post-occupancy data to complete its LBC documentation. But already the building is making a mark on the design and construction industry. The response of the air-and-weather barrier's manufacturer is just one indication. And if the Bullitt's bid for living-building status proves successful, it could serve as a blueprint for an ecologically restorative office building almost anywhere in the world, says Jason McLennan, ILFI's CEO: "People won't be able to say that living buildings aren't practical anymore."