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2.04. COATING SYSTEMS FOR STEEL PRESSURE FILTER AND BACKWASH TANK <br />EXTERIOR <br />A. Pressure <br />Vessel and Backwash Tank Exterior, Complete Replacement <br />1. <br />Coat all exterior surfaces, including but not limited to steel piping, <br />structural members, openings and appurtenances, equipment and pipe <br />supports, and other exterior surfaces. <br />2. <br />System Type: Zinc Primer with Polyamine Epoxy, NSF Coating <br />3. <br />Surface Preparation: NACE 2/SSPC-SP 10 Near White Metal Blast with a <br />sharp angular profile of 2.0 - 3.5 mils or as recommended by the coating <br />manufacturer. <br />4. <br />Paint thickness specified is the required range of dry mil thicknesses to <br />be applied. The minimum DFT shall be strictly enforced. <br />a. Painting coverage rates: Manufacturer's published theoretical <br />coverage in sq. ft. per gallon less 20 percent. <br />b. Paint shall be applied at the wet film thickness that is <br />recommended by the coating system manufacturer to achieve the <br />specified dry film thickness. <br />C. Apply by brush one (1) additional coat of intermediate coat to <br />ensure a uniform coat of primer thoroughly worked into and <br />around all seams, welds, bolt assemblies, rivet heads, plate <br />overlap seams, and other irregularities in the surface. <br />5. <br />Primer: Sherwin Williams Corothane I Galvapac Zinc Primer 1 K or <br />Tnemec Hydro -Zinc Series 91-1-12 at 2.5 - 3.5 mils DFT. <br />6. <br />Stripe Coat: Sherwin Williams Macropoxy 646 PW Epoxy - white, <br />B58WX600 Series or Tnemec Series N140. Brush and/or roller apply a <br />stripe coat to all welds and seams. Required at 4.0 - 6.0 mils DFT. <br />7. <br />Finish Coat: Sherwin Williams Macropoxy 646 PW Epoxy - blue or <br />Tnemec Series N140 at 4.0 - 6.0 mils DFT. <br />2.05. ACCESSORIES <br />A. Coating Application Accessories: <br />1. Accessories required for application of specified coatings in accordance <br />with manufacturer's instructions, including thinners. <br />2. Products of coating manufacturer. <br />2.06. SANDBLAST ABRASIVE <br />A. Use proper equipment and abrasives when blast cleaning to produce the mil <br />profile, within the range of 2.0 to 3.5 or as recommended by the coating <br />manufacturer. Do not reuse sand or flat abrasives. <br />B. The abrasive used shall be of the type that is graded as to proper size, shape <br />and hardness. It shall be free of contaminants and shall not embed itself in the <br />blasted surface. Silica sand, Flint, Garnet or Quartz type abrasives shall be <br />chemically washed, dried, dust, dirt and fines free, resistant to fracture <br />(shattering), and contain no leachable contaminates. Synthetic (non-metallic and <br />non -siliceous) abrasives such as Silicon Carbide, Aluminum Oxide and <br />Refractory Slag products shall meet the above criteria. THE USE OF REDUCED <br />OR DUST FREE ABRASIVE BLASTING IS REQUIRED. THE USE OF A <br />PROPRIETARY ADMIXTURE TO THE SELECTED ABRASIVE SUCH AS <br />P05367-2016-000 / Mounds View 09 96 20 - 7 PRESSURE VESSEL COATING <br />2019 WTP Rehabilitation SYSTEMS <br />