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Water Tower Coatings Weather the Elements Beautifully: Polyurethane Coating System Standing the Test of Time

Published on 2008-04-04. Author : SpecialChem

Pittsburgh -- Neither sun, nor rain, nor 13 years of western Pennsylvania winters have affected the polyurethane coatings on a 1.5 million gallon water steel storage tank built by the Municipal Authority of the Township of Robinson (MATR), near Pittsburgh. The reason? A specially formulated four-coat polyurethane system is ensuring a long-lasting, quality appearance as well as superb corrosion resistance.

Compare the 2007 photo on the right with the 1994 photo on the left. The polyurethane coating system on the Robinson Township water tower looks as good today as it did when it was first applied more than 13 years ago

The massive hydropillar consists of a fluted cylindrical column with an elevated storage tank. Located just off busy Route 279 South, the MATR water tower is a highly visible landmark as commuters travel between downtown Pittsburgh and the Greater Pittsburgh International Airport.

Engineers specified the four-coat polyurethane system because it would withstand the rigors of hot and cold temperature extremes, air pollution, acid rain - and virtually anything Mother Nature would send its way. The coatings, manufactured by Tnemec Company of Kansas City, Mo., were formulated with Desmodur polyisocyanates from Bayer MaterialScience. According to Tnemec's Sean Carlin, the coatings were expected to perform well for at least 20-25 years. This was an important consideration, since the Municipal Authority wanted to be sure the water tower would not only look good, but also require little maintenance.

The coating process began at the Clive, Iowa, fabricating plant of Pitt-Des Moines Inc. Crews blasted the tank's exterior plates to SSPC-SP6 standards, then sprayed on Tneme-Zinc 90-97, a zinc-rich polyurethane primer. This primer not only provides excellent exterior corrosion resistance, it protects the inside dry areas of the water tank as well.

Once the tank was erected in its permanent location, painting contractor Neumann Company Contractors, Inc. of Romeoville, Ill., took over. The weld seams were blasted to surface prep specifications, and the primer was touched up wherever necessary. The exterior plates then received two coats of Tnemec Series 73 Endura-Shield aliphatic acrylic polyurethane, which provided a semi-gloss finish and long-lasting color retention for the white and pale blue pigments. A topcoat of Tnemec Series 76 Endura Clear high-gloss polyurethane was applied last, bringing the total polyurethane coating DFT on the tank's exterior to 7.5-11.5 mils. In all, the Neumann crew painted 104,300 square feet of steel with approximately 900 gallons of polyurethane coatings.

Nearly 13 years later, the coating system on the Robinson Township water tower is still corrosion-free and in excellent condition. MATR is just as satisfied with the coatings today as it was back in 1994. Carl Angeloff, P.E., head - NAFTA Business Development and Manager - BD Corrosion, Bayer MaterialScience, notes, "Since this water tank is located close to the Bayer MaterialScience headquarters, we've been able to observe the performance of the coatings first-hand on a regular basis. I must say, the finish still looks picture perfect - and should stay that way for at least another decade."

Bayer MaterialScience LLC is one of the leading producers of polymers and high-performance plastics in North America and is part of the global Bayer MaterialScience business with nearly 15,400 employees at 30 sites around the world and 2007 sales of 10.4 billion euros. Business activities are focused on the manufacture of high-tech polymer materials and the development of innovative solutions for products used in many areas of daily life. The main segments served are the automotive, electrical and electronics, construction, medical, and sports and leisure industries. Our inorganic basic chemicals unit produces chlorine and related essential products for the chemicals industry. Let us give life to your vision. Bayer MaterialScience - Where VisionWorks.

Bayer Corporation, headquartered in Pittsburgh, is a subsidiary of Bayer AG, an international health care, nutrition and innovative materials group based in Leverkusen, Germany. In North America, Bayer had 2007 net sales of 8.1 billion euros and employed 16,800 at year end. Bayer's three subgroups, Bayer HealthCare, Bayer CropScience and Bayer MaterialScience, improve people's lives through a broad range of essential products that help diagnose, prevent and treat diseases; protect crops and enhance yields; and advance automobile safety and durability.

This website may contain forward-looking statements based on current assumptions and forecasts made by Bayer Group or subgroup management. Various known and unknown risks, uncertainties and other factors could lead to material differences between the actual future results, financial situation, development or performance of the company and the estimates given here. The company assumes no liability whatsoever to update these forward-looking statements or to conform them to future events or developments.

Source: Bayer MaterialScience


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