CoatingsPro Magazine

JAN 2009

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 88 of 107

JOB AT A GLANCE PROJECT: The rehabilitation and repainting of the interior and exterior of the 1,420,000 gallon steel standpipe known as the "Chatham Tank," located in Chatham, New Jersey COATINGS CONTRACTOR: Alpine Painting and Sandblasting 17 Florida Avenue Paterson, NJ 07503-2114 (973) 279-3200 SIZE OF THE CONTRACTOR: 30 member in-house crew; a 5-6 man crew worked this project PRIME CLIENT: ABOVE New Jersey American Water Company has extremely high water quality standards — even employing taste testers to verify that sol- vents cannot be tasted in the water when the tanks are returned to service. So TIC specified a solvent-free coating on this project: Carboline Polibrid 700-Resin-A mixed with Polibrid 705-Catalyst-B, a low-VOC elastomeric polyurethane coating system. inspector reviewed the tank to make sure it was clean enough for the blast standard. The abrasive blasting phase took the six man crew (including the crew foreman) about three weeks to complete. Prior to application of the interior product, Alpine took steps to facilitate any exterior welding and to make sure that the exterior welding didn't burn the interior coating — which had an unexpected effect on the job scope. Scaturro explains this unusual step: "In an effort to not damage the newly applied interior coating, we suggested to the water company that we could complete an exterior welding that would prepare for any future tank refurbish project — and we would do it prior to applying the interior lining system. New Jersey American Water then determined that since they were so happy with the interior work we had already completed, they issued a change order to refurbish the exterior of the tank as well." So, just before the interior coating work was complete, Alpine had the welder return and weld stand-offs for the communications antennas arrayed on the exterior tank roof, the shell ladder, and roof ladder, as well as uprights for the roof railing system. Many of the pitted areas in the tank's interior needed no particular attention due to the coating thickness; however the 50 pitted areas that were excessively deep, or more than half the thickness of the tank's steel, needed to be pit welded. The welder also installed 10 patch plates in the floor. This stage took about two weeks for the welding and scaffolding and the crew made ready to complete the new coating of the tank interior. THE INTERIOR COATING PROCESS The coating selected for this project, Carboline Polybrid, a two part system consisting of Carboline Polibrid 700-Resin-A and Polibrid 705-Catalyst-B (mixed 2:1 ratio), is a single-coat, extremely quick cure coating — which allowed the interior painting project to be conducted in the late winter. Project specifications prepared by TIC required dehumidifica- tion during blasting and the addition of heat to maintain proper New Jersey American Water Company 213 Carriage Lane Delran, NJ 08075 SUBSTRATE: Steel SUBSTRATE CONDITION: Interior: Widespread pitting and holes on floor; existing interior coating contained chromium pigments Exterior: The primer coat was lead-based, but in fair condition SIZE: The tank is approximately 46' 3" in diameter and has a nominal shell height of approximately 116' DURATION: The project interior began the first week of Dec. 2007 and ended mid-Feb. 2008. The exterior work began March 4, 2008 and was substantially complete by May 23, 2008 UNUSUAL FACTORS: New Jersey Water was utilizing end-of-year funding so much of the billing had to be in before the close of the year The surrounding neighborhood was in very close proximity, with one The use of 100% solids coating on the interior of the tank significantly reduced the VOCs released Forced ventilation in accordance with coating manufacturer's recom- MATERIALS/PROCESS: Interior: mendations, specifications, and AWWA D102-97 was required, as was a dust collection system during abrasive blasting Weld new roof vent, 2 new shell manholes, and rig coupling to the top of tank for work platforms, as well as refurbish the exterior of tank so any future exterior work would not burn interior coating Using 12-40 coal slag abrasive pretreated with Fesi-bond, sandblast Running heaters and dehumidification equipment to maintain ambient tank to NACE No. 2 SSPC-SP 10. The tank was sandblasted to "near white metal (SSPC-SP10) Crew used a D.E. Sterns 14/20 high-voltage pinhole tester to check the cured coating for pinholes and holidays. Patching was achieved continued on page 90 temperature of approximately 40ºF, spray-apply Carboline Polibrid coating system, Polibrid 700-Resin-A and Polibrid 705-Catalyst-B, in a 25-35-mil-thick single coat. The coating was applied using a Graco Hydra-Cat and a Wiwa 500F spray gun fitted with a Graco HD RAC625 tip January 2009 J 89 house only 50' from the tank. The neighbors were extremely concerned about noise, so Alpine used equipment staging and sound attenuation to meet the neighborhood's needs

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