America’s Greenest Office Building
The Bullitt Center is a six-story, 52,000-square-foot building aiming to meet the net-zero-energy, net-zero-water Living Building Challenge
I’m just back from a week in Seattle, where I attended the Living Future Conference, which this year had a theme of resilience and regeneration — a major focus of mine with the Resilient Design Institute. While there I visited what is almost certainly the greenest office building in America, if not the world.
The Living Future Conference was created initially to provide a networking and learning venue for designers and builders involved in creating buildings that achieve the Living Building Challenge. Unlike its better known cousin, the LEED Rating System (Leadership in Energy and Environmental Design) of the U.S. Green Building Council, the Living Building Challenge (LBC) is not a points-based system, but rather a collection of very specific, very challenging requirements.
To achieve LBC certification, buildings must:
- operate on a net-zero-energy basis — using no more energy, on an annual basis, than is collected by the building (LBC certification can not be earned until a full year of data is collected proving that it is actually operating to be zero-net-energy);
- operate on a net-zero water basis—using no more water on an annual basis than is collected on the site;
- contain no “red list” chemicals — the LBC maintains a long list of chemicals that cannot be used, including polyvinyl chloride (PVC), brominated flame retardants, and heavy metals like the mercury found in fluorescent lights; and
- address various other requirements related to the building site, health, equity, and beauty (yes, beauty). Each of these categories (energy, water, materials, site, health, equity, and beauty) are referred to as petals in the program.
Needless to say, achieving LBC certification is very hard. Since the launch of the program seven years ago only a handful of buildings have achieved full certification (4 and counting), and another half-dozen have been recognized for achieving LBC requirements in individual petals. When it comes to larger, multistory office buildings, the requirements for LBC have seemed almost out of the realm of possibility — at least until now.
A very green new office building in Seattle
The Bullitt Center is a remarkable building that is well on its way to becoming the first sizable commercial office building to achieve LBC certification. The six-story, 52,000 square-foot commercial building, which is owned by (and houses) the Bullitt Foundation, had its grand opening on Earth Day this year (particularly appropriate, since the long-time president of the Bullitt Foundation, Denis Hayes, was the director of the first Earth Day in 1970).
The building was designed by the Miller Hull Partnership in Seattle, with other members of the integrated designBuilding design in which different components of design, such as the building envelope, window placement and glazings, and mechanical systems are considered together. High-performance buildings and renovations can be created cost-effectively using integrated design, since higher costs one place can often be paid for through savings elsewhere, for example by improving the performance of the building envelope, the heating and cooling systems can be downsized, or even eliminated. team including Point32, PAE Consulting Engineers, Foushee, Luma Lighting Design, 2020 Engineering and Berger Partnership.
Among the building’s features:
- Highly energy-efficient building envelopeExterior components of a house that provide protection from colder (and warmer) outdoor temperatures and precipitation; includes the house foundation, framed exterior walls, roof or ceiling, and insulation, and air sealing materials.. The mostly glass building has a modeled energy-use intensity (EUI) of 16 kBtu1,000 Btus per square foot per year. This makes it 83% more efficient than typical office buildings in Seattle. This is achieved with such features as triple-glazed, low-eLow-emissivity coating. Very thin metallic coating on glass or plastic window glazing that permits most of the sun’s short-wave (light) radiation to enter, while blocking up to 90% of the long-wave (heat) radiation. Low-e coatings boost a window’s R-value and reduce its U-factor., argonInert (chemically stable) gas, which, because of its low thermal conductivity, is often used as gas fill between the panes of energy-efficient windows. -filled windows, automated exterior shades, and high insulating values for non-glazed portions of the building.
- Solar-electric system. A rooftop 242-kilowatt (kW) photovoltaic(PV) Generation of electricity directly from sunlight. A photovoltaic cell has no moving parts; electrons are energized by sunlight and result in current flow. (PV) system is projected to deliver 100% of the building’s electricity needs on an annual basis. Denis Hayes told me, however, that since Seattle isn’t known as one of the sunnier places, this net-zero-energy performance will depend on the weather each year. On a good year, the PV array should have no problem meeting that goal, but some years there is a lot less insolationAmalgamation of the words “incoming solar radiation” that means the total amount of solar energy that strikes a given surface in a given time. It is commonly expressed in kilowatt-hours per square meter per day. than average. To get a large enough PV array on the roof to supply electricity for six floors, the PV array cantilevers out over the walls. (Incidentally, Hayes knows what he’s talking about relative to solar, as he served in the late-1970s as director of the Solar Energy Research Institute — now the National Renewable Energy Laboratory — in Golden, Colorado.)
- Ground-source heat pumpHome heating and cooling system that relies on the mass of the earth as the heat source and heat sink. Temperatures underground are relatively constant. Using a ground-source heat pump, heat from fluid circulated through an underground loop is transferred to and/or from the home through a heat exchanger. The energy performance of ground-source heat pumps is usually better than that of air-source heat pumps; ground-source heat pumps also perform better over a wider range of above-ground temperatures. heating and cooling. Twenty six 400-foot-deep wells drilled beneath the building provide a heat source and heat sinkWhere heat is dumped by an air conditioner or by a heat pump used in cooling mode; usually the outdoor air or ground. See air-source heat pump and ground-source heat pump. for the building. Both heating and cooling are delivered through radiant systems. This all-electric system is projected to use only 5% of the electricity produced by the building’s PV system.
- Lighting and plug loads. DaylightingUse of sunlight for daytime lighting needs. Daylighting strategies include solar orientation of windows as well as the use of skylights, clerestory windows, solar tubes, reflective surfaces, and interior glazing to allow light to move through a structure. provides 90% of the building's lighting needs. Power consumption for electric lighting and plug loads (computers and other devices that plug into outlets) is kept low in part through a unique, internal “cap-and-trade” system in which tenants have a specific energy budget. If they use less electricity than their budget, they can trade with other tenants in the building who may need more. Tenants sign a thick contract that includes penalties if their energy budgets are exceeded. (The International Living Future Institute, which manages the Living Building Challenge, has just moved into the building so will be walking the talk.)
- Operable windows. Many of the large triple-glazed windows that comprise much of the wall area of the building are operable. Rather than hinging open, the German Schüco mechanisms keep the windows parallel to the wall as they open, which improves the ventilation. The mechanisms are automated but have manual override. To achieve the LBC requirement for local materials, Schüco partnered with a local glazingWhen referring to windows or doors, the transparent or translucent layer that transmits light. High-performance glazing may include multiple layers of glass or plastic, low-e coatings, and low-conductivity gas fill. fabrication company to produce the units, and that company is now going to be a regional producer of high-performance curtainwall systems.
- Rainwater harvesting. The building has a 56,000-gallon cistern for storage of rainwater that is harvested on the roof. This water, after filtration and multistage treatment and polishing, can supply 100% of the building’s water needs, including drinking water, the three ounces of water used per flush in the foam-flush toilets, showers for bicycle commuters (there are showers on each floor), and landscape irrigation. (Permitting issues are still being worked out to allow the building to use only site-harvested water, but hopefully that will be resolved.) Interestingly, while Seattle is cloudy a lot of the time (225 cloudy days per year) and it rains a lot (150 days per year), Hayes noted that the total rainfall is modest: only 37 inches per year on average, compared with 43 for Boston and 49 for New York City. The exception to the self-contained water system is the building’s sprinkler system, which the city required be on municipal water pressure.
- Composting toilets. To get the building’s water consumption low enough to satisfy it entirely with site-harvested water required composting toilets. The four foam-flush toilets on each floor (24 total) deliver waste to ten Phoenix composting units located in the basement. As far as I know, this is the only building over four stories to rely exclusively on composting toilets.
- Durability. The building’s timber structure is designed for a 250-year life, and the building envelope or skin has a projected life of 50 years before it will need replacement — which can happen without affecting the structure.
- Local materials. Reflecting the Pacific Northwest’s timber resource as well as a desire to minimize embodied energyEnergy that goes into making a product; includes energy required for growth, extraction, and transportation of the raw material as well as manufacture, packaging, and transportation of the finished product. Embodied energy is often used to measure ecological cost. of materials, all of the structural wood for the building is local Douglas fir from forests that were certified to Forest Stewardship Council (FSCForest Stewardship Council. An independent, nonprofit organization that promotes responsible forest management through the use of a third-party certification process. FSC certification includes a chain-of-custody requirement that tracks sustainability of wood products from growth to end use.) standards. Glulam beams are produced from two-by dimension lumber. Incidentally, the Bullet Center is the largest heavy-timber building constructed in Seattle since the 1920s.
- Safe materials. Tremendous effort was expended to avoid the use of several hundred red-list chemicals. Manufacturers whose products were used have to go through the International Living Future Institute’s Declare program or produce a Health Product Declaration to certify that red-list chemicals are not used. This feature of the Living Building Challenge is have a huge influence on product manufacturing today, leading to greener products. A number of manufacturers altered their manufacturing to comply with LBC requirements.
- Occupant comfort and daylighting. All tenants in the building will have access to daylight, either from adjacency to outside walls or through glass interior partition walls. Even the stairwell is fully daylit, a particular requirement of Hayes, who calls it the “irresistible stair” that will encourage occupants to walk rather than taking the elevator. Views of downtown Seattle from the stairwell make the walk worthwhile.
Yes, it cost more: $355 per square foot
As might be expected, the Bullitt Center wasn’t an inexpensive building. At $18.5 million dollars, or $355 per square foot, this is about $50 per square foot above the average for high-quality, Class-A office buildings in the region, according to the Bullitt Foundation. But it is a demonstration of pushing the envelope and proving that the environmental impacts of buildings can indeed be dramatically reduced.
Office space in the building is being leased at $28 to $30 per square foot per year, slightly higher than average for Seattle, but tenants get free electricity and water at that price — as long as they keep within their allotted limits.
The Bullit Center is indeed a milestone building — I believe one of the most important commercial buildings of the past 50 years.
Alex is founder of BuildingGreen, Inc. and executive editor of Environmental Building News. In 2012 he founded the Resilient Design Institute. To keep up with Alex’s latest articles and musings, you can sign up for his Twitter feed.
- Alex Wilson
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