CoatingsPro Magazine

MAY 2015

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 51 of 92

COATINGSPRO MAY 2015 51 But there was no time to savor the irony. CMT had only 11 days to remove the remaining polyurea coating system, prepare the steel, and spray-apply a Sherwin-Williams SHERFLEX S coating system. Te plant closed one Friday afternoon in early February and drained the tank. Over the weekend, truckers from Rain for Rent delivered nine 20,000-gallon (75,708 L) mobile liquid containment tanks. Te tanks were plumbed, and on Monday morning, plant maintenance personnel dished the project over to CMT. Covered With Glaze Jobsite access couldn't have been better! CMT rolled its 18-foot (6 m) work trailer to within about 40 feet (12 m) of the waste- water tank. Te trailer contains a 5 KW Honda generator and various necessities, such as sump pumps, rollers, sprayers, and personal protective equipment (PPE). Te frst order of business was to erect scafolding, but there was a problem. Te bottom of the 50-foot-diameter, 18-foot-tall (15 m x 6 m) tank was covered with several feet of a gritty substance. To keep from To get going, the crew removed the old polyurea and the several feet of grit covering the tank's bottom. They needed to shovel everything out before they could bring in their scaffolding. JOB AT A GLANCE PROJECT: Install an elastomeric polyurethane waterproof coating system inside, and an aliphatic finish coat outside, a 200,000-gallon (757,082 L) wastewater tank at a North Carolina food processing facility COATINGS CONTRACTOR: Carolina Management Team, LLC 1911 Baker Rd. High Point, NC 27263 (336) 431-7708 SIZE OF CONTRACTOR: About 33 full-time employees SIZE OF CREW: 5 crew members PRIME CLIENT: A major food manufacturing company that wishes to remain unnamed SUBSTRATE: Steel CONDITION OF SUBSTRATE: Poor; rusted welds on tank exterior SIZE OF JOB: 5,652 sq. ft. (525 m²) total DURATION: 11 days UNUSUAL FACTORS/CHALLENGES: » Owner rented nine mobile wastewater tanks to keep plant in production » Icy conditions forced two-day delay » Lingering cold front meant changing primer and altering spray sequence MATERIALS/PROCESSES: To the Interior: » Removed failing coatings with ultrahigh pressure (UHP) water jetting » Wet and dry abrasive blasted to NACE No. 2/SSPC-SP-10: Near-White Metal Blast with 3-mil (76 microns) anchor profile » Applied Sherwin-Williams DURA-PLATE 235 hold primer at 1–1.5 mils (25–38 microns) dry film thickness (DFT) » Applied Sherwin-Williams SHERFLEX S topcoat at ~60 mils (1,524 microns) total DFT in two passes To the Exterior: » Pressure washed walls with 5,000 psi (35 MPa) to remove surface contaminants » Used power tools on and spot-primed welds by brushing and rolling 4–6 mils (102–152 microns) DFT of Sherwin-Williams MACROPOXY 646 » Brushed and rolled spot-primed areas with COROTHANE 1 aliphatic at 3–5 mils (76–127 microns) DFT » Abraded existing urethane coating with 100-grit sandpaper » Brushed and rolled entire tank with COROTHANE 1 aliphatic finish at 3–5 mils (76–127 microns) DFT SAFETY CONSIDERATIONS: » Used scaffold with guard rails inside tank » Wore overalls, gloves, aluminum leg guards, steel-toed boots, 3M N95 masks, and face shields when water blasting » Wore full blast suits with fresh air supply and CO2 monitor when dry abrasive blasting » Wore 3M 6000 series full face respirators, coveralls, gloves, and spray hoods when spraying Among other things, the crew wore aluminum leg guards and face shields when water blasting; full blast suits with fresh air supply when dry abrasive blasting; and full face respirators and spray hoods when spraying.

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