City and county officials set lofty goals for the San Francisco Public Utilities Commission (SFPUC) administrative building, tasking KMD Architects to design “the greenest urban building in the United States.” The resulting showpiece, which consolidated SFPUC staff from two leased buildings into one new city-owned headquarters, serves as a national model for environmentally responsible building design and life-cycle performance. Economic savings in annual lease rates coupled with design strategies to decrease utility and operating costs will result in a 26-year payback and provide $118 million in energy cost savings over 75 years.
Jury: “For a large, urban, commercial office building, its on-site black- and graywater treatment system is quite significant. And that pioneering ambition is important in terms of water that’s coupled with positive metrics related to the structure’s energy use intensity. Its material use and lighting power density were also very low. A very big story is the on-site wastewater treatment, but that’s complemented generously by other building performance attributes.”
KMD, working with San Francisco-based Stevens and Associates, slashed the building’s consumption of natural resources through a number of innovative approaches, including one of the country’s first on-site graywater and blackwater treatment systems. The Living Machine wetland-based system reclaims and treats all of the building’s wastewater to satisfy 100 percent of the water demand for the building’s low-flow toilets and urinals. It treats 5,000 gallons of wastewater per day and reduces per person potable water consumption from 12 gallons to 5 gallons.
The facility will exceed California’s Title 24 requirements for energy efficiency in new office buildings by 55 percent, according to SFPUC estimates. Lighting is comprised of high-performance, energy-efficient fixtures on dimming ballasts that are integrated with interior window shades and exterior blinds. Daylight is optimized and regulated through light shelves and automatic shades that are tied to the trajectory of the sun. Fixed fins at the south façade serve as light shelves to bounce daylight even further into the interior space. In addition, 7 percent of the building’s energy demands is generated on site through rooftop PV arrays and a wind-turbine tower at the north façade, which was designed to channel the wind to optimize energy production.
Michael Rossetto, senior associate, KMD Architects: “With a distinctly urban character, the building also imparts a sense of dignity; demonstrates the enterprise of the city government; achieves harmony, proportion, balance, and clarity; and reflects the traditions of San Francisco. … The building envelope was designed to optimize the energy from the sun to create a productive work environment, as well as naturally ventilate the adjacent open office plan. Nighttime ventilation flushes excess heat from the building, cooling the thermal mass of the concrete frame. Integrated light shelves bounce daylight deep into the plan, while shading substantial portions of the glazing while photovoltaics directly capture the sun’s energy.”
Sustainably quarried stone was used extensively throughout the project, which was designed to harmonize with its classically styled Civic Center neighborhood. Following extensive design coordination, which included collaboration with a local concrete supplier, the design team created six different low-cement concrete specifications. Portland-cement replacements ranged from 40 percent to 70 percent, with slag and flyash as the green cementitious replacement materials, decreasing the project’s carbon footprint by 7.4 million pounds of carbon dioxide emissions compared to conventional concrete mixes.
BY THE NUMBERS
Building gross floor area: 27,500 square feet
Estimated percent of occupants using public transit, cycling, or walking: 80
Percent of views to the outdoors: 91
Percent of spaces within 15 feet of an operable window: 30
Percent reduction of regulated potable water: 40
Potable water used for irrigation: No
Percent of rainwater from maximum anticipated 24-hour, two-year storm event that can be managed on site: 100
Total EUI (kBtu per square foot per year): 41
Net EUI (kBtu per square foot per year): 38
Percent reduction from national average EUI for building type: 61
Lighting power density (watts per square foot): 1.22
Third-party rating: Designed to LEED Platinum standards; also meets Title 24.
Total project cost at time of completion (land excluded): $146.5 million
Data and project information provided by KMD Architects and Stevens and Associates firm via AIA COTE Top Ten entry documents.