“Overcoming challenges while relining a 1.3-mile penstock for the Devil Canyon Powerplant”

(Note: The following case study is detailed more on Sherwin-Williams website. Click here to read.  The contractor leveraged BlastOn’se RIPT (Robotic Interior Pipe Tool) blasting robot for the interior lining. Photos below.)

The California Department of Water Resources (DWR) needed to repair a 1.3-mile-long penstock outside of San Bernardino, California due to corrosion and abrasion. The penstock, which ranges in diameter from 8 to 9.5 feet and plunges 1,200 feet through harsh terrain, is critical to the water supply and power generation in Southern California. The project required a coating that would have a long life, comply with state regulations on volatile organic compound (VOC) emissions, and could be applied using equipment small enough to fit inside the penstock. The solution was to use two coats of Sher-Glass® FF Low VOC from Sherwin-Williams Protective & Marine, applied at 15-20 mils dry film thickness per coat. This two-component, glass flake-reinforced amine epoxy coating is formulated for immersion service and provides corrosion, impact, and abrasion resistance. It also has a contractor-friendly pot life and reinforced film that enhances performance and edge protection. The project was carried out by Unified Field Services Corporation over the course of two approximately eight-week periods in January through March of 2020 and 2021. To prepare and coat the inside of the penstock, the team used automated blasting equipment and a wheeled BlastOne robot. The coating was applied using K71FH2 Graco machines and spray lines up to 800 feet long. The project was completed with minimal downtime and met state regulations on VOC emissions.

After completion and inspection in spring 2021, the Devil Canyon Penstock resumed its full operation of supplying water to the Devil Canyon Powerplant and distributing treated water to users in the San Bernardino region. The powerplant generates electricity from water traveling through the plant, with some of the water also being directed to Lake Perris through the Santa Ana Pipeline.