CoatingsPro Magazine

NOV 2016

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 35 of 68

COATINGSPRO NOVEMBER 2016 35 wet for about 10 to 15 seconds," Winter said. Containment was not required on this project, and primer overspray precautions amounted to little more than not parking trucks near the tank. After blasting and priming the tank exterior, the crew parked their Graco airless and geared up to apply two layers of Amercoat 385 intermediate coat. ey were to apply 3 to 8 mils (76.2–203.2 microns) total DFT of that coating. So far, weather hadn't been much of a factor, and the job was basically on track. But since springtime in Texas can dish up unpleasant meteo- rological conditions, the crew needed to shift work to the tank interior ASAP! But there was a problem. Once both coats of Amercoat went down, they'd only have a 30-day maximum recoat window at 70° F (21.1° C) before the PPG PSX 700 topcoat was specified to be applied. With bad weather on the way, it would take too long to complete the entire 10-million-gallon (37.8 million L) tank before tackling the interior. ere had to be a way to get inside faster, and Winter found it! His crew would split the Amercoat into two installments. "Amercoat 385 has an unlimited (non-immersion) Inside and out side the tank, the 10- to 15 -person crew wore fall protection when working on scaf folding, boom lif ts, and near the roof perimeter. When blasting, they also wore air-supplied hooded respirators. To access areas between the roof plates and the tops of the rafters, the entire 231-foot-diameter (70.4 m) roof had to be lifted approximately 4 inches (10.2 cm) off the support braces. JOB AT A GLANCE PROJECT: Apply interior and exterior coating systems to a 10-million-gallon (37.8 L) steel water tank in Austin, Texas COATINGS CONTRACTOR: Blastco, a TF Warren Group Company 1400 Woodloch Forest Dr., Suite 500 The Woodlands, TX 77380 (832) 299-3200 SIZE OF CONTRACTOR: ~125 employees SIZE OF CREW: 10–15 crew members PRIME CLIENT: City of Austin 2006 E 4th St. Austin, TX 78702 (512) 974-2000 SUBSTRATE: Steel CONDITION OF SUBSTRATE: Fair, built in 1988 SIZE OF JOB: ~205,000 sq. ft. (19,045.1 m²) DURATION: 160 days allowed UNUSUAL FACTORS/CHALLENGES: » To access areas between roof plates and tops of rafters, the entire 231-foot-diameter (70.4 m) roof was jacked up. » The project was slated for winter/spring when water demand was low. » There was a two month interval between applications of Amercoat 385. MATERIALS/PROCESSES: To the Exterior: » Abrasive blasted tank walls and roof with a 3.5-mil (88.9 microns) minimum anchor profile » Spray applied 3–4 mils (76.2–101.6 microns) dry film thickness (DFT) of PPG Dimetcote 9H inorganic zinc silicate primer in one pass » Roll and brush applied two coats of Amercoat 385 to achieve 3–8 mils (76.2–203.2 microns) total DFT; pressure washed before second coat » Roll applied two coats of PPG PSX 700 topcoat to achieve 5–7 mils (127.0–177.8 microns) total DFT To the Interior: » Lifted the roof approximately 4 inches (10.2 cm) off the support braces » Abrasive blasted tank walls, ceiling, floors, rafters, and braces to NACE No. 2/SSPC-SP-10: Near-White Blast Cleaning » Spray applied direct to metal one coat of PPG Amerthane 490 to achieve ~30 mils (762.0 microns) DFT SAFETY CONSIDERATIONS: » Evacuated from steel tank during electrical storms » Wore fall protection when necessary » Wore air-supplied hooded respirators when abrasive blasting

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