CoatingsPro Magazine

JAN 2013

CoatingsPro offers an in-depth look at coatings based on case studies, successful business operation, new products, industry news, and the safe and profitable use of coatings and equipment.

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Page 74 of 100

By Jack InnIs perators of a Southwestern coal-fired power plant were in a pickle. Along an 1,800-foot (548.64 meter) stretch of 10-foot-diameter (3.05 meter) underground concrete pipeline that comprised the plant's cooling system, 17 of the 20-foot-long (6.10 meter) sections failed internal inspection. The 40-year-old pressure pipe system was comprised from inside out of 2 inches (5.08 cm) of concrete, a steel liner, 2 more inches (5.08 cm) of concrete, a post tension cable wrap, and roughly 2 inches (5.08 cm) of exterior concrete. If the internal failures were not remedied quickly, corrosion could reach the steel liners, and the resultant failure could shut the entire plant down. Plant managers likely would have ordered the sections dug up and replaced, but there was a rub. The cooling lines ran underneath buildings, equipment, and other structures. With pipe replacement off the menu, the managers began looking at a coatings-based rehab solution, but soon realized that any new coating system would need to be as strong, or stronger, than the original concrete pressure pipe. The fix would be complex. It would likely call for a hydroblast to ICRI CSP-3 surface profile, installation of a 3 - 5 mil (76.20 - 127 micron) (DFT) epoxy primer, hand troweling a 20-mil (508-micron) (DFT) layer of epoxy thickened with fumed silica to fill voids and create a tack coat, installation of a saturated strengthening fabric, laying down 130 mils (3,302 microns) (DFT) of thickened epoxy into which would be pressed in hoop fashion 208-mil (5,283.20 micron) diameter steel wire at 2.5 wires per inch (2.54 cm), and another layer of wetted fabric. As if this recipe needed more spice, plant managers could only take the cooling system offline for 28 days! Several contractors eyeballed the project and came to the Photos courtesy of PerforMance soLutIons aDVantaGe anD reMote orBItaL InstaLLatIon, LLc same conclusion. The short shutdown window, the fact that 17 sections were scattered throughout 1,800 feet (548.64 meters) of pipeline, the amount of equipment needed to work multiple sections simultaneously, and the sheer manpower required made this a losing proposition. À La carte Meanwhile, several technical and practical pipeline prep and coatings innovations were coming together that would make this project feasible. In the center of this confluence stood Structural (formerly Structural Preservation Systems or SPS), headquartered in Hanover, Maryland. Ron Rozek, inventor and 11-year Structural subcontractor, was working on a process to shorten pipeline prep time by removing hydroblasting from the equation. Hydroblasting is a great form of surface prep in situations where the introduction of water is not a problem. Ironically, in this underground watercarrying pipeline, it was. "Once the pipe is pumped out, the clock starts ticking on a project such as this," says Rozek, who owns the Winneconne, Wisconsin-based Performance Solutions Advantage. "The last thing you want to do is reintroduce water by hydroblasting and then wait for the pipe to dry. On this job, nobody had time to sit around and wait for that." As part of his gig with Structural, Rozek had done a lot of noodling to find more efficient ways to prep pipelines. In fact, a year earlier he called Ed Zaharias of Stoc Products out of Spring Grove, Illinois and described one of his ideas. Zaharias listened as Rozek talked about putting the entire blast operation onto a motorized gurney with a rotating nozzle—blasting à la carte, so to speak. PiPeline Rehab À La Carte 74 coatingsPro g January 2013

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