By Joe Mellott, IMETCO

The Islais Creek Motor Coach Maintenance & Operations Facility truly redefined the meaning of a long-term project. The design of the San Francisco Municipal Transportation Agency’s new facilities, which included the construction of three buildings on a 10-acre site in southeast San Francisco, was initiated in 1990. The facility was designed to accommodate a growing demand for SFMTA services, but was halted for more than two decades due to a lack of funding.

The project, which represents the first new SFMTA rubber-tire vehicle maintenance facility in the last 60 years, includes a fuel and wash building, a light and heavy maintenance building, an administration building, bus storage and land acquisition. Once funding was received and the project was given the green light, designs had to be altered to accommodate technological changes that had occurred in the last 20 years.

Initially, the maintenance building was designed to service 40-foot compressed natural gas buses, which were commonly used in the '90s. Two decades later, the SFMTA has moved on to newer technology – hybrid diesel. Along with that, the demand for services has grown even more, prompting the transportation authority to use an increased number of 60-foot busses compared to 40-foot busses. Therefore, the structure had to be modified to accommodate those larger vehicles.

In addition to changes in the building’s functionality, some modifications were made to the design to improve performance and create a facility engineered to last at least 50 years or more.

Will Kwan, senior architect for San Francisco Public Works, was brought on prior to the start of construction to review the facility’s original design and modify as necessary. One of the first things he noticed was that the original design specified corrugated Galvalume metal for the walls and roof. But with the building’s proximity to the San Francisco Bay at just a half-mile and the rusty conditions of adjacent buildings, Kwan proposed the Galvalume be replaced with solid zinc.

Zinc has a better ability to resist corrosion than steel. In fact, when zinc is exposed to the moisture and carbon dioxide that is present in the atmosphere, a protective layer of zinc carbonate forms on its surface, prohibiting the corrosion process that steel experiences. This barrier provides protection for the building’s exterior.

“There has been a big educational push in recent years talking about the value of zinc and the fact that it doesn’t corrode and has excellent weathering properties,” Kwan said. “While I have used zinc in roofing, this was my first project using the material for siding.”

Along with its long-term performance, solid zinc requires no maintenance – a welcome benefit for a city that doesn’t have a regular maintenance budget for its buildings.

“When funding becomes available through grants or through voter propositions, it’s far and few between,” Kwan said. “So when we do have a chance to either renovate or, in this case, build a new facility, we need to select high-performance materials and design it for the long-term as well as make sure it requires very low maintenance to upkeep.”

Phase 1 of the project included construction of the fuel and wash building and administration building. Unable to find a manufacturer who would warrant the application of corrugated metal on a roof with a 3:12 slope, Kwan – working with a manufacturer’s representative of The Garland Company, Inc. – modified the roof design to standing seam metal.

TwinLok^™ 1 mm zinc standing seam metal panels, manufactured by Garland’s sister company, IMETCO, were installed on the building’s saw tooth roof, which was angled to optimize southern exposure and maximize power production when retrofitted with photovoltaic panels. The north-facing clearstory openings were in-filled with a translucent window system to allow natural daylight into the interior spaces to minimize electrical lighting during the day.

“The saw tooth form is very common in industrial buildings,” Kwan explained. “That’s another sustainable element for the building. The more day lighting we can provide, the less electricity we use.”

IMETCO’s Cor-Pan corrugated zinc metal cladding was used for the walls, as part of a rainscreen system designed to provide energy efficient performance. Waterproofing Associates, Inc. of Mountain View, California, and SJ Amoroso Construction, Inc. of Redwood City, California, served as contractors on the project.

In addition to choosing a long-lasting, low maintenance material like zinc for the exterior of the building, there were various other sustainable attributes incorporated into the design. Although Phase 1 was not required to achieve LEED certification, like Phase 2 of the project was, the design incorporated many sustainability features listed in the LEED point system, such as:

• Constructed on a brownfield site (former industrial site)
• Minimizing off-site soil removal/dumping
• Water conservation (bus wash to utilize reclaimed water system)
• Energy efficiency by maximizing day-lighting (with north-facing clearstory windows)
• Configuration of roof ready for photovoltaic solar panels for on-site power generation
• High recycle content in the construction materials used
• Direct outside air minimizing mechanical HVAC

Phase 1 construction was completed in February 2013. Phase 2 of the project included construction of the 130,000-square-foot maintenance building, which was very similar to the fuel and wash building, with the same zinc roof panels and wall cladding in glacier gray. The only difference was the installation of photovoltaic panels on the roof, which provide credits toward the building’s LEED certification. Phase 2 was substantially completed by the end of February 2018. Both phases of the project, which totaled roughly $127 million, were funded through the Federal Transit Administration (FTA). The new facilities will have the capacity to maintain and operate 166 40-foot busses or 110 60-foot busses and will provide a comfortable work environment for more than 300 SFMTA employees.

Lisa Chow, among a few other project managers with the SFMTA through the course of the project, understands the necessity of having a good maintenance facility. The SFMTA is responsible for the buses, light rail vehicles, cable cars and historic streetcars of Muni, with those vehicles used more than 725,000 times every day.

“Having a good facility that is well equipped and well-staffed is really important for us,” Chow said. “If our fleet isn’t properly maintained, there could be problems with us meeting our service demand. It’s a huge milestone for the agency to have this facility constructed.”

Joe Mellott currently serves as vice president of IMETCO (Innovative Metal Company, Inc.), where he is involved with multiple elements of the business, including business integration, innovation, industry relationships and acquisitions. Mellott holds multiple patents for roof-related innovations and received the 2006 Industry Statesman Award from the Roof Coatings Manufacturers Association (RCMA) for his work in advancing roof coatings industry technology. Mellott has served as the technical chair and president of the Roof Coatings Manufacturers Association (RCMA). He has also served on the board of the Cool Roofs Rating Council (CRRC) and has held memberships in the Roof Consultant Institute (RCI), the National Roof Contractors Association (NRCA), and the Asphalt Roofing Manufacturers Association (ARMA). A graduate of Case Western Reserve University, Mellott holds a bachelor’s degree in Polymer Engineering, is a frequent contributor of technical articles to industrial publications, and a participant in innumerable roofing and polymer-related organizations.