Levi’s Stadium pumping system on the Super Bowl stage

SANTA CLARA, CALIF. — Home to Super Bowl 50, the $1.3 billion Levi’s Stadium is a model of sustainability.

With a 27,000-sq.ft. green roof, owners’ suites decked out in reclaimed wood, and farm-to-table concession offerings, the 68,500-seat stadium includes a wide variety of “green” features. But none of these is more crucial to its operations than the use of recycled water for its flushing and irrigation systems, which account for 85% of the facility’s water usage.

The recycled-water pressure booster system built by California Hydronics Corp. (CHC) using Bell & Gossett pumps, heat exchangers and other products, taps into the Santa Clara Valley Water District water recycling system. This eliminates the need to use fresh water to flush toilets and to irrigate the natural grass field, green roof and other areas, which is of particular concern in drought-ridden California.

According to stadium water assessment estimates, the system will save more than 42 million gallons of water per year. High efficiency, low flow fixtures were used throughout — Sloan 1.28 gpf toilets and .125 gpf urinals — along with solar, timed and metered lavatory faucets — 0.5 gpm.  Water usage for water closets has been reduced 20%, urinals reduced 87.5%, and lavs reduced 66%.

“With water use reduction with the urinals and recycled water, the savings of domestic potable water is significant and is on par to using less water with more fixtures—for recycled vs. domestic,” said Kevin Coyne, vice president estimating, F.W. Spencer & Son, Inc., the installing plumbing contractor.

ACCO Engineered Systems, the mechanical contractor for the project, procured a variety of Bell & Gossett products, including Rolairtrol air separators, Series 60 inline pumps, 1510 end suction base mounted pumps, and VSX double suction pumps for the hydronic systems. Xylem Bell & Gossett brazed plate and GPX gasketed plate and frame heat exchangers were specified and supplied for the project, offering the highest level of thermal efficiency for the condenser water system.

All of the Bell & Gossett products included in the stadium’s building systems are noted for their efficiency and were selected by Turner-Devcon, who drafted design development drawings and specifications, along with the support of ME Engineers.  ACCO and F.W. Spencer completed the permit packages, which included the selection of Bell & Gossett centrifugal pumps and Goulds Water Technology e-SV multistage centrifugal pumps for the recycled-water pressure booster system.

“F.W. Spencer has used B+G pumps on many of our projects, and one of the reasons we keep going back to them is they have proven to be reliable, perform as designed, and have outstanding support through their vendor Cal Hydronics,” said Coyne.

Because of the size of Levi’s Stadium’s recycled water system, a special cross connection test had to be developed and implemented along with special differential pressure test procedures. Recycled water is delivered to the project from the local municipality, and enters a 15,000-gal. break tank. Water is pulled from the break tank to feed two pressure zones in the stadium for flushing fixtures, and also a separate pump system for the field watering. 

ACCO worked closely with general contractor, Turner Devcon Joint Venture, on the development of a sequencing plan for logistics, stocking and installation.  The stadium was built as multiple independent projects running concurrently, with the construction team working together to meet the scheduled completion on time.  Due to the tight schedule, logistics were the key challenge of the job. 

ACCO, Turner Devcon Joint Venture and the architect worked in unison to fit the mechanical systems into the unconventional structure. “The size and complexity of the project made the entire coordination process very challenging, and therefore very important. As BIM leaders, we partnered with some of the other project team members in solving design conflicts and issues that arose during coordination,” said Larry Jimenez, ACCO project manager for Levi's Stadium.

Super Bowl, Super Flush

The stadium, hosted Super Bowl 50 and a crowd of more than 70,000 people, was up to the task.

“A full two seasons have been played at Levi's Stadium thus far, in addition to a number of special events,” said Jimenez. “Many of these were at full capacity, and the systems have been exercised at this capacity. The facilities crew is very familiar with the systems ACCO installed and we are confident they will be able to handle any situations that may arise.”

Nevertheless, F.W. Spencer was asked to have a representative during the Super Bowl to monitor booster pump operations on the recycled and domestic water booster systems. 

“ME Engineers, which has done dozens of stadium projects throughout the United States, asked that we monitor the flow to see how many pumps cycled on and what the max flow was at what point in the game — recycled and domestic,” said Coyne.

F.W. Spencer also monitored restroom lines at specific times and compare that data with pump trending data.

“This is, to our knowledge the first stadium to be done with recycled water for flushing fixtures, which will allow them to see actual flow on the low flow, solar powered flush valves, separate from the domestic usage,” said Coyne.

Super Flush: been there, done that

According to Coyne, challenges were met during the project — schedule, sequencing, special cross connection testing for dual-plumbed buildings, Super Flush preparation and coordination, and final certification by the municipality and state for the recycled water system.

“A recycled-water pressure booster system ensures adequate water is available when everyone goes to the bathroom at one time, like halftime at a football game,” said Mark Handzel, vice president of Product Regulatory Affairs and director of HVAC Commercial Buildings at Bell & Gossett, a Xylem Brand.

The “Super Flush,” a test of the system, was conducted in April 2014 to make sure the system was fully operational before the stadium opened. During the test, hundreds of workers and volunteers simultaneously flushed every toilet and urinal and turned on every sink in the stadium for about 30 minutes.