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To save energy, the schedule for lighting the City Hall dome at night was cut by two hours. This dome is the fifth-largest dome in the world and is 42 feet (13 m) higher than the dome on the U.S. Capitol. (Jamin Barnes)

Soon to celebrate its centennial, San Francisco’s historic City Hall has reached a sustainability milestone. It was recently awarded Leadership in Energy and Environmental Design (LEED) Platinum certification for Existing Buildings: Operation & Maintenance (EBOM), distinguishing it as the oldest building in the United States to achieve the U.S. Green Building Council’s highest rating.

This accomplishment is the result of sustainable energy, water, and ventilation retrofits as well as conservation strategies, along with operational changes and a location that provides access to amenities—bicycle racks and electric vehicle–charging stations—that encourage the use of alternative transportation resources.

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The inside of the San Francisco City Hall dome. A lighting control system with sensors mounted inside and on the roof judges the amount of natural light pouring into the light court in the dome then adjusts lighting accordingly. (Jamin Barnes)

“The strong point of putting this level of sustainability in a historic building is it demonstrates that not only can this be done in new buildings, it can be done in old buildings, too,” says Masoud Vafaei, an engineer in the San Francisco Public Utilities Commission (SFPUC) and the Civic Center District program manager who manages sustainable upgrades to city buildings, pointing out that this is important because the majority of U.S. buildings have been around awhile.

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This project is part of a broader sustainability plan for all city structures in the Civic Center District and involves a partnership of the SFPUC; the City Administrator’s Office; and the U.S. Environmental Protection Agency (EPA), which provided expertise and a $700,000 grant to support water conservation upgrades.

The project also represents an agreement between the city and the Clinton Global Initiative to create a showplace that pushes sustainability beyond a building to a neighborhood concept. “We are excited to be able to show that you can be this efficient in old buildings,” Vafaei says, noting that an overall goal is to use the Civic Center to showcase green, available, proven technologies and strategies. “It is hoped that when visitors see and learn about this, they will want to use it in their own work environments.”

The Clinton Global Initiative brought together city staff with green experts and resources in an informational forum to discuss sustainable strategies used elsewhere that might be useful for this project. City and EPA staff then worked together to draft a plan for upgrading Civic Center buildings.

“City Hall is just one of the buildings where we’re taking this approach,” Vafaei points out, noting that eight buildings will be brought up to sustainable standards in terms of energy and water efficiency and indoor air quality. Four of the buildings are historic Beaux-Arts structures, including City Hall, the Opera House, the Veterans Building, and the Bill Graham Civic Auditorium, which present challenges in terms of making sustainable alternations without affecting their historical value.

The City Hall project, however, presented the greatest challenge, because it is listed on the Federal Historic Register; therefore, any alterations to this edifice are subject to robust review to ensure that its aesthetic and historic integrity is not compromised.

“There are certain things we couldn’t do because of the historic value, like shade controls or window tinting,” Vafaei notes. “Some of the lighting resembles candlelight and is a [historic] aesthetic, so we are looking for a LED technology manufacturer to come up with replacements to support change-outs,” he adds.

Hosting numerous events throughout the year, in addition to regular council and committee meetings, City Hall consumes an extraordinary amount of energy. With 100 percent renewable hydroelectric power from the Hetch Hetchy Water and Power System, the SFPUC, therefore, focused on upgrades that improve energy and water efficiency.

“We wanted to take advantage of natural daylighting from skylights on the dome and fourth floor that floods the rotunda and public spaces in light courts, but it’s not always available,” says Vafaei, This problem was solved with a daylight management system that uses sensors on the roof and inside to judge when a cloud passes over and turns up electric lights. Other strategies to reduce electricity use included replacing old fluorescent lights on the first floor with newer, high-efficiency, low-mercury fluorescent technology and turning off dome lighting at night two hours earlier.

City Hall’s 100-year-old steam heating system is powered by natural gas. While the original building control system heated and cooled spaces based on size, a new demand control ventilation system uses sensors to measure CO2 levels to detect the number of people in a space. This novel system maintains air freshness similar to the outdoors based on CO2 level and heats and cools as needed, Vafaei says, explaining that as CO2 rises, the system adjusts ventilation and heating or cooling to maintain comfort.

Other energy strategies to improve comfort and conserve energy involved installing thermostatic valves on radiators to keep them from overheating; joining together a split cooling system to more efficiently cool the side of the building that gets the hottest; and adding speed controls to fans on building mechanicals so they can be ramped up or down as needed.

Upgrading building plumbing fixtures with low-flow toilets and urinals and new faucets reduced City Hall water consumption by 825,000 gallons per year, notes Amanda Dougherty, SFPUC water conservation administrator.

A total of 76 toilets, which used a 3.5-gallon-per-flush (gpf) standard, and 17 old, 2-gpf urinals were replaced with new 1.28-gpf toilets and 0.125-gpf urinal models. In addition, 200 vintage faucets, which used seven gallons of water per minute (gpm), were replaced with new look-alike faucets with aerators that restrict water flow to 0.5 gpm.

The marble paneling and flooring in toilet stalls, which are aesthetically historical, were a major concern for Dougherty, as any marble disfigured during replacement of toilet and urinal fixtures had to be replaced with the same type of marble material. But luckily City Hall happened to have saved a stock of this marble from the original construction.

After solving the marble issue, Dougherty encountered another problem: finding a toilet bowl to meet the existing plumbing connections. In working with Zurn, a fixture manufacturer, she was able to get a new bowl poured that was configured to connect with the original City Hall plumbing. The new bowls, however, were longer in length than the old toilet bowls, which resulted in a door clearance issue that required restroom doors to be modified so they open in the opposite direction.

City Hall’s sustainability upgrades will reduce energy consumption by 20 percent annually and save more than 825,000 gallons of water per year. “These new combined water and energy retrofits are good for the environment and will save taxpayers money,” commented SFPUC general manager Harlan Kelly in a press release.

Pointing out that getting an old building to this level of green is not a “walk in the park,” Vafaei says, “We chose to go above and beyond what everyone else is doing and worked hard at it, because it was the right thing to do. This building has been here 100 years and will be here many more to come, so it made perfect sense to create a space that supports this use.”

Vafaei is now focused on energy upgrades at Symphony Hall, and the Veterans Building is undergoing a major renovation that includes both sustainable and seismic retrofits. Dougherty has already replaced plumbing fixtures at the Veterans Building, Symphony Hall, the Opera House, the Department of Public Health administration building, and the Bill Graham Civic Auditorium, which will save an estimated 46 million gallons of water per year.