LEED Case Study: 100 Years Young

By Anne Cosgrove
From the September/October 2015 Issue

Opened in 1915, San Francisco’s City Hall was celebrated this past June for its centennial, just one month after being awarded LEED Platinum certification for Existing Buildings: Operation & Maintenance (EBOM). Consequently, the LEED certification has distinguished the 600,000 square foot building as the oldest in the United States to achieve this level of certification from the U.S. Green Building Council.

Shortly after receiving the LEED plaque and in announcing the centennial celebration for the Beaux-Arts style building, Mayor Edwin M. Lee, said, “San Francisco City Hall is a world-class landmark with a storied history for trailblazing policies that have had a global impact. The investment we are making 100 years later is making history again.”

The journey towards LEED certification has been in progress for a number of years now (green cleaning programs and recycling are staples of the city’s operations there), but making it to the finish line called for partnerships with fellow city and county agencies as well as with private entities.

In 2012, Mayor Lee announced that the City and County of San Francisco had filed for LEED certification for the building. This was one of eight buildings in the Civic Center District that was put on the path toward LEED certification, as part of a broader plan to increase the sustainability of the District facilities.

City Administrator, Naomi Kelly, was instrumental in the LEED pursuit, having worked for the city in several previous positions (which included establishing environmentally preferred purchasing guidelines). Says Kelly of the Mayor’s 2012 announcement, “To pursue certification, we had to provide some significant upgrades.”

Much of these improvements involved mechanical systems. Kelly explains, “Some areas of the building did not have mechanical systems adequate to qualify the building for an Energy Star score, which is a prerequisite for LEED. So our initial focus was on HVAC mechanical upgrades and building management system upgrades, at a cost of about $430,000.” This contributed towards the building being Energy Star certified in 2013, with a score of 96, followed in 2014 with a score of 93.

An existing collaboration with the San Francisco Public Utilities Commission (SFPUC) played a significant part in gaining momentum. SFPUC was working on, and continues to implement, sustainability improvements in the city’s Civic Center Plaza.

Says Kelly, “We were fortunate in that SFPUC was beginning a plumbing fixture retrofit project for several of the Civic Center buildings, as part of an EPA funded grant. We leveraged the grant to help install low flow faucets and toilets in all of our restrooms and other applicable spaces. These have been in place since early 2015, and we expect to save approximately 825,000 gallons of water per year.”

A total of 76 toilets, which used a 3.5 gallon-per-flush (gpf) standard, and 17 2.0 gpf urinals were replaced with 1.28 gpf toilets and 0.125 gpf urinal models. Two hundred faucets were replaced with faucets with aerators that restrict water flow to 0.5 gpm. Kelly notes that in comparison the previous faucets used up to 7.0 gpm.

Lighting was another major area where the team pursued energy savings. “We also spent about $250,000 on interior lighting fixtures and lighting management systems,” says Kelly. These improvements were also funded in part by the EPA grant.

“We installed efficient infrared halogen lighting throughout many spaces in City Hall, and the fixtures can be dimmed in response to available daylight.”

Another major piece of the lighting improvements was to install a daylight management system. As part of this, the artificial lighting throughout the facility automatically dim when a predetermined level of natural light is available to the interior. The primary places daylighting is utilized includes the central rotunda and the building’s North and

South Light Courts. (Used often before the advent of electricity, a light courts is an open shaft of space surrounded entirely by walls, which provides extra light to a building interior.) At City Hall, these Light Courts are frequently used for social and other events.

Indoor air quality in the frequently occupied Light Courts as well as throughout the building was another area high on the list. The building’s steam heating system is powered by natural gas, and while the original building control system conditioned spaces based on their size, now a demand control ventilation system uses sensors to measure carbon dioxide (CO2) levels. Prior to the retrofit, spaces were often overconditioned, and now as CO2 rises, the system adjusts ventilation and heating or cooling to maintain comfort. “We expect this technology will reduce energy use by at least 50%, compared to the older system,” says Kelly. “This automation really allows for better monitoring and optimization.”

For more than 80 years, San Francisco City Hall has operated on renewable energy, hydroelectric power sourced from the Hetch Hetchy power system located 160 miles away in the Sierra Nevada mountain range. Under the purview of SFPUC, the Hetchy Power System is composed of three hydroelectric powerhouses: Moccasin Powerhouse, which includes a small, in-line hydroelectric unit, Kirkwood Powerhouse and Holm Powerhouse. The combined total hydroelectric output for these facilities is over 400 megawatts. Hydroelectric generation at Moccasin and Kirkwood Powerhouses rely on gravity-driven water flowing downhill from the Hetch Hetchy Reservoir. Holm Powerhouse generates energy from gravity-driven water flowing downhill from Cherry Lake.

On average, the system generates 1.6 billion kilowatt hours of hydroelectric power annually, according to SFPUC.

Kelly notes that the system was has been seismically retrofit over the past decade.

Historic Considerations

The age of San Francisco City Hall posed several challenges, and the project team worked together to address structural and aesthetic issues that arose. The building is listed on the National Register of Historic Places, and the City Hall Preservation Advisory Commission was instrumental in providing information to maintain the structure’s integrity.

One of the more challenging constraints involved the retrofit of plumbing fixtures, because these were surrounded by marble flooring and paneling original to the building. “We needed to be mindful of how to restore the marble around those fixtures. So we took great care in making sure it was restored in a way that would meet our Commission’s guidelines.” The city discovered a stock of marble from the original construction, so was able to address this issue.

Kelly also notes some lighting fixtures chosen were constrained by historic guidelines and requirements. “We were very careful to follow those guidelines,” she says “The concern was not about the type of lighting, but about making sure the fixtures and light looked a certain way.”

Measures that were precluded from the LEED project due to the historic considerations included shade controls and window tinting.

Partnerships Propelled Certification

As a public entity and also due to the scope of the LEED project, the presence of multiple stakeholders brought great value to the process and the results. As noted previously, Kelly’s office had been working closely with SFPUC on water and energy system improvements, along with the state Department of Environmental Protection, and the U.S. EPA. The project also involved an agreement between the city and the Clinton Global Initiative to create a showplace that propels sustainability beyond one building to the neighborhood.

In May 14, 2015, when City Hall received the LEED certification, U.S. EPA Administrator Gina McCarthy was present to deliver remarks, saying, “San Francisco has long been a leader and innovator at the forefront of solutions to combat climate change and reduce energy and water consumption. As the entire nation watches California endure its fourth year of drought, we all must do our part to use renewable energy, be energy efficient, and conserve our precious water resources.”

SFPUC has been an EPA WaterSense Partner since 2011, helping reduce water usage at City Hall and in the Civic Center District of San Francisco. [For more on EPA WaterSense and water management strategies, read, “Look, Listen, and Learn To Find Leaks” on page 36 of this issue.]

At the May event, Kelly stated, “San Francisco City Hall is a world-class building with a storied history for trailblazing policies that have had a global impact. As we approach City Hall’s centennial celebration, City Hall today makes history again as the oldest U.S. building to achieve LEED EBOM Platinum Certification, the hallmark of sustainable building design.”

SFPUC general manager, Harlan Kelly, Jr., said, “These new combined water and energy efficiency retrofits are good for the environment and will save taxpayers money.”

Since 2002, the SFPUC has retrofitted 180 City buildings for nearly 48,000 MWh/yr in energy savings and two million therms/yr in natural gas efficiencies. The projects were reported to be saving city taxpayers $5.5 million each year in energy costs.

SFPUC’s energy efficiency retrofits in Civic Center have resulted in nearly 3.5 million kWh of electricity and associated natural gas and steam usage.

For City Hall, in all the energy efficiency improvements are expected to reduce consumption by approximately 20%, while the water efficiency upgrades are estimated to save approximately 825,000 gallons of water per year.

With the LEED pursuit successful, Kelly notes the next step is to track energy and water consumption in City Hall to ensure expected savings are occurring. “This time next year, we should have data on these aspects,” she says. “And we are consistently looking at how to make our Civic Center as a whole more sustainable.”

Meanwhile, LEDs have been installed in the exterior light fixtures around the building, replacing 220 incandescent bulbs. In addition to the expected energy and cost savings, the LED lighting has lifted a maintenance burden. For special events, such as Independence Day or a local sports team getting a win, these outdoor lights are displayed in the appropriate colors. “We used to apply gels, which took time of course. Now we can change the colors from a computer,” says Kelly.

Another highlight unveiled at the City Hall Centennial celebration earlier this year in June was a permanent multi-media projection system, which projects lights and images on the façade of City Hall during special events. It’s another way the building continues to evolve as a 100 year old facility in the 21st Century.

This article is based on project literature and an interview with Kelly (www.sfgsa.org).

Share your thoughts in the Comments section below. To send an overview of your new construction or renovation story for article consideration, send an e-mail to acosgrove@groupc.com.