CoatingsPro Magazine

MAY 2017

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 82 of 84

82 MAY 2017 COATINGSPROMAG.COM Industry Insight W hen we talk about field- erected, on-site storage tanks, the coating applicator faces many more challenges than in a controlled fabrication shop. Consider an elevated water storage tank that might be more than 100 feet (30.5 m) in height. Besides worrying about proper surface prepa- ration and coating application, the worker is subject to all sorts of safety considerations, including fall protection, confined areas, weather conditions, safe scaffolding, and crane use. On top of the on-site challenges, coating manufacturers in the water industry continue to develop increas- ingly sophisticated paintings and linings. Today's water tank buyer wants the steel water storage tank to have a 50- to 100-year life. Coatings are expected to provide corrosion protection for more than 20 years, even though externally they are subject to damaging ultraviolet rays, rain and snow, and air pollutants. Internal linings face challenges, too. ey remain submerged in water, usually at all times, but they must keep water pure, meeting requirements such as those of the National Science Foundation (NSF)/American National Standards Institute (ANSI) 61: Drinking Water System Components — Health Effects. e lining must act as a barrier to prevent water and oxygen from interacting with the steel and contami- nating the water. What's in the Coating? Today's modern coatings may incor- porate three layers, such as three-part epoxies, double epoxy coats with either a zinc first layer or a urethane outer layer, zinc-urethane-fluorourethane application, or zinc-epoxy-urethane application. Fluorourethanes are particularly popular with municipali- ties; their properties allow for a highly finished outer layer that identifies the town with its name or logo or its most famous landmark. Many of these coatings are applied to meet American Water Works Association (AW WA) D102: Coating Steel Water-Storage Tanks. e purpose of this standard is to provide the minimum requirements for coating steel water-storage tanks, including materials, coating systems, surface preparation, application, and inspec- tion and testing. Large terminal tanks built to American Petroleum Institute (API) 650: Welded Tanks for Oil Storage or API 620: Design and Construction of Large, Welded, Low-Pressure Storage Tanks have similar coating application concerns in the field as water tanks. However, these industrial tanks are usually painted white to minimize the stored fuel or chemical from getting so hot that emissions are too great. However, other specialty applica- tions can come into play, particularly if the inside of the tank must be lined to hold materials other than water or oil. Tanks storing acids may have rubber linings. Tanks storing ethanol may have the bottom and the first layer of steel in the shell lined to protect the massive storage tank from developing stress corrosion cracking. Advances in the industry are constantly occurring, so it's important for the coatings contractor to get as much information as possible pertain- ing to these types of coatings and linings. e many trade shows for large fuel storage tank owner/operators and coating manufacturers are potential references. Coatings Business Opportunities Maintaining infrastructure to assure long tank life, especially for potable water storage, means more coating inspections, repairs, and applications. And while I've talked mainly about steel field-erected storage tanks here, the same applies to concrete tanks. Some in the industry say concrete tanks don't need linings or repairs, but that's far from the truth. Not only must concrete tanks meet NSF 61 as well, but there are also instances of biofilms and molds forming on uncoated concrete. To prevent contamination of stored water, linings are a necessity. In my role with STI-SPFA, I get to see a wide variety of coatings and linings used for different industries and different end uses. I learn something new every day! But one thing is certain: Steel-erected tanks rely on coatings for corrosion protection and long life. CP Photo courtesy of Steel Tank Institute/Steel Plate Fabricators Assoc. By Wayne Geyer, Executive Vice President of Steel Tank Institute and Steel Plate Fabricators Association (STI-SPFA) Field-Erected Steel Storage Tanks

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