It’s hard to know what a sustainable building even looks like today, with a glut of different “green” classifications, LEED levels, and marketing pushes. But one criterion, the Living Building Challenge (LBC), founded in 2006, outstrips the others. And now its flagship building—a 50,000-square-foot office building in downtown Seattle called the Bullitt Center—is being called the greenest commercial building in the world.
The $30 million building’s opening ceremony is today, a fitting date as the foundation’s president, Denis Hayes, is also the founder of Earth Day. Once tenants are moved in—educational facilities on the bottom and office space up top—the structure is expected to use only 23 percent of the energy typically required for a building of its size.
That’s down to super-stringent requirements. The four Living Buildings in existence use on average half the energy of a LEED Platinum building. They can't contribute any waste to the environment; can only use as much water as they can harvest from rainwater; and must generate all their own energy. Building materials must be locally sourced and can't contain any of 362 red-listed chemicals often found in construction materials.
The Bullitt Center’s Capitol Hill site is one of the densest neighborhoods in all of Seattle. Previously two-thirds covered by asphalt and one-third by a bar (don’t fret, it relocated), the lot was underdeveloped for the area.
In keeping with the building’s sustainable nature, tenants must adapt to this dense environment. There’s no onsite parking for cars, but there are 25 covered spots for bicycles, with more around the building's exterior, and showers on every floor that make it easy to clean up after a ride to work. Since the building is located on a bus route, near a new streetcar line, and in walking distance to a future light rail, driving to work should be the last choice for tenants of the Bullitt Center.
The building will create 100 percent of its own energy, primarily through the use of solar panels. The center needed a city variance on its building permit to lay 14,300 square feet of solar panels across the top of the building and over the sidewalk, capturing every drop of sun possible in a city with 226 annual cloudy days. Hayes says the Pacific Northwest’s limited sun makes Seattle one of the toughest spots in North America at which to design an LBC building.
Triple-pane. Argon-filled. Low-emissivity. Thermal-break. These terms all describe the oversized 10-foot-by-4-foot windows spanning the high-ceiling walls to not only help draw natural light deep inside the structure and fulfill 82 percent of all lighting needs, but also do so while conserving energy.
The windows are controlled by a computer "brain" in the building that determines whey they should pop open to freshen the place up with outside air. (Indoor air quality is one of the metrics used by LBC.) Outside louvers—also automated—shift to shade the sun or bounce it in, depending on heating needs. At night, to cool the building, this brain can also open the windows and “flush the heat,” filling the building with fresh night air, keeping the center comfortable—and energy efficient—come day.
To reduce use on Portland cement, the material responsible for 7 percent of global CO2 emissions, Bullitt uses fly ash (a waste product of coal burning) to create cement. Builders removed chemicals typically added to the fly ash mix and sourced the product from 125 miles away. The re-bar used was roughly 95 percent post-consumer recycled steel.
In what could serve as the single largest lifestyle change for the tenants, Hayes says, they’ll have to flush the toilet both before and after they use it. All toilets in the building are composting toilets, which accelerate the natural composting process, forcing the evaporation of water—which comprises 90 percent of waste—through vents and turning the remaining waste into compost with a mix of oxygen, moisture, heat and bacteria (odorless, no less).
Temperature control sucks 40 percent of a typical building’s energy use. While daylighting and fancy windows on the Bullitt Center decrease the need for heating and cooling, there are still energy needs.
For those the building relies on an in-floor radiant heating/cooling system. Twenty-six wells full of a glycol mixture drop 400 feet below the soil where they are heated or cooled by the relatively constant soil temperature—a setup akin to the system in the rear of a refrigerator. The system offers a significant energy savings—Bullitt will use 83 percent of the heating energy of a typical commercial building.
The LBC has a list of toxins that builders must avoid. A long one. And it took building planners an extra year just to scour the “red list” and figure out how to source over 1,000 everyday building materials without choosing ones with known toxins. From paint to plywood, almost every material in the building required a rethink.
As part of the material procurement process, materials needed local sourcing, not more than 300 miles away, if possible. It took creativity and, in some cases, ingenuity on the part of local vendors to recreate products using natural elements, whether a window sealant or a wood glue. In some cases, those new, natural processes proved more cost-effective for the company and became a new way of doing business, such as Portland’s Prosoco, which completely reworked a formula to eliminate toxic phthalates from its air-tight liquid building wrap.
In addition tenants are part of a cap-and-trade system. The system allows them each an energy budget that is transferable to other tenants, so that they will be able to “buy” more energy if they desire. But it comes at a cost—say, sacrificing one of those coveted bicycle slots.
Such achievements show that what some people thought were wild ideas actually work, says Mary Ann Lazarus, sustainability director at architectural firm HOK, who isn’t associated with the project. On a wide range of scales—from rainwater in coffee pots to tinkering with whole supply chains—the example of the Bullitt Center, she says, demonstrates “new out-of-the-box creative solutions” that adapt to the building’s local environment.