Challenging Relining Project in California Wins First Place in Sherwin-Williams Impact Awards

A project relining a 1.3-mile-long penstock for the Devil Canyon Power Plant earns first place honors for the California Department of Water Resources and contractor Unified Field Services Corp.

Challenging Relining Project in California Wins First Place in Sherwin-Williams Impact Awards

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A project team braving tight quarters, steep vertical drops and an aggressive coatings schedule to reline an 8- to 9.5-foot-diameter, 1.3-mile-long penstock for the Devil Canyon Power Plant in San Bernardino, California, has earned top honors in the 2021 Sherwin-Williams Impact Award program.

The Impact Award recognizes exceptional projects that feature high-performance coating and lining materials from Sherwin-Williams Protective & Marine. The challenging, multi-year project involved blasting and relining the penstock’s entire interior while navigating grades of nearly 75% in spots, figuring out how to manage equipment access via 30-inch wide entry points located 1,000 feet apart and maintaining warmth inside the pipeline when outside temperatures were near freezing and winds occasionally reached 70 mph. The winning team includes the California Department of Water Resources and industrial services firm Unified Field Services Corporation.

 “The 2021 Sherwin-Williams Impact Award winners faced a range of difficult challenges, while successfully overcoming them to extend the service lives of critical infrastructure assets. That’s the kind of dedication we look forward to honoring each year via the program,” says Bryan Draga, global vice president of marketing for Sherwin-Williams Protective & Marine. “These winners have found optimal solutions to water and wastewater challenges that save time, labor and precious municipal budget dollars – not only in the execution of the coatings projects but also over the long term as these applied systems continue to prevent corrosion and enhance aesthetics.”

The Sherwin-Williams Impact Award program recognizes application contractors, specifiers and owners for excellence on North American water and wastewater projects that have a compelling effect on the industry with regard to public safety, asset protection and infrastructure life cycle improvement. Eligible projects included any water-related structure that was new, restored and/or rehabilitated in 2020 and was completed using coating and lining materials from Sherwin-Williams Protective & Marine.

A devil of a time

Just walking alongside the 1.3-mile-long penstock outside San Bernardino would be a challenge: The pipe, which ranges in diameter from 8 feet to 9.5 feet, plunges 1,200 vertical feet through harsh terrain as it exits the mountains to meet the California DWR Devil Canyon Power Plant. Relining the penstock’s interior meant not just navigating grades of nearly 75% in spots and battling occasional winds up to 70 mph, but also dealing with access points located 1,000 feet apart, using entry ports just 30 inches wide and maintaining interior warmth while elevation-related temperatures delivered snow outside. And since the pipeline is critical to Southern California’s water supply and power generation, relining the penstock to guard against corrosion and abrasion was a crucial upgrade that needed completion with minimal downtime. Although the overall project unfolded over several years, surface preparations and lining applications were completed in a pair of approximately eight-week periods from January through March of both 2020 and 2021, with crews working around the clock.

The project required a coating that would deliver long life while still complying with state regulations on volatile organic compound emissions – and that could be applied using equipment that would fit inside the penstock. The solution was to apply two coats of Sher-Glass FF Low VOC from Sherwin-Williams Protective & Marine, applied at 15-20 mils dry film thickness per coat.

A two-component, glass flake-reinforced amine epoxy coating, Sher-Glass FF Low VOC is formulated for immersion service, providing corrosion, impact and abrasion resistance. It offers direct-to-metal application, contractor-friendly pot life and a reinforced film that enhances performance and edge protection. This project included a gray primer coat and a white finish coat, which featured Sherwin-Williams Opti-Check optically activated pigments embedded in the lining to enable future quality control inspections using an eye-safe ultraviolet light. Application involved using K71FH2 Graco machines to move 10,000-plus gallons of coating material via spray lines up to 800 feet in length. This equipment needed to be broken down and reassembled to get it in and out of the penstock at each narrow entry port.

Bakersfield-based Unified Field Services Corporation — specializing in pipeline projects for water utilities and other industrial sectors — was contracted for the project. To carry out the surface cleaning, preparation and coating within the short windows of time for work in the penstock, Sherwin-Williams rallied support services through staging, storage, demonstration and troubleshooting sites in nearby Riverside. Teams also addressed many operational details ahead of time, such as testing pumps to ensure they could deliver the pressure necessary to achieve proper material atomization through the larger applicator tip opening that the reinforced coating required. Due to the access limitations, the applicators needed to be able to spray with two guns supported by a single piece of equipment.

In January through March 2020, the first stage of the project tackled prepping and coating roughly one-third of the penstock. The relining was completed from January through March the following year, with the difference in productivity between the phases due to experience with the equipment and environment, as well as the use of automated blasting equipment in the second project phase to prepare the pipe’s interior to a clean, uniform profile.

During the 2021 phase, the teams used a wheeled BlastOne robot to clean the penstock. Additionally, with the extensive dehumidification equipment and a ventilation and air flow system in place inside the pipe, the coating team was able to begin working at the upper end while the blasting team continued to prep lower segments. Controlling the atmosphere inside the pipe was not only vital to safe operation, but also to ensure the temperature remained above 55 degrees F so the coating would perform properly. That was no mean feat in late winter where, even in Southern California, the hills saw occasional snow outside the penstocks.

Other unique solutions included using rigging systems in steep sections that allowed the workers to apply coatings without walking on the pipe’s surface and adapting the blast robot to assist in moving the applicator pump when spraying coatings.

Following completion and inspection of the pipeline in spring 2021, the Devil Canyon penstock resumed full operation, supplying water to the Devil Canyon Power Plant, which generates electricity from water traveling through the plant. Some of that water continues to Lake Perris through the Santa Ana Pipeline, while the rest is moved to afterbays before being treated and distributed to water users in the San Bernardino region.


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