The Southern Nevada Water Authority (SNWA) is a regional agency whose mission is to manage water resources and develop solutions that will ensure adequate future water supplies for the Las Vegas Valley. Its primary water resource is the Colorado River via Lake Mead. Since 2000, persistent droughts have resulted in decreasing Lake Mead water levels. To reduce Southern Nevada’s reliance on the Colorado River, SNWA has begun planning for the development of in-state groundwater resources north of Las Vegas. Initial planning efforts identified project specific requirements that could potentially justify the use of polyurethane lining systems in lieu of traditional cement mortar lining for over 200 miles of large diameter water transmission pipeline.

The potential benefits of using polyurethane lining on welded steel pipelines in lieu of traditional cement mortar lining include improved hydraulic characteristics, superior long term outdoor storage capability, reduced impact on water quality during low or no flow periods, and reduced cost because of the ability to optimize the steel wall through use of higher strength steel. While the potential benefits are significant, a potential down side is the lack of long term history on the use of polyurethane as a lining. Polyurethane lining systems have been used in water pipelines for 12 to 15 years and standards have been developed by the American Water Works Association (AWWA C222 and C210). The standards however are for minimum and general requirements of polyurethane and epoxy coatings for steel water pipe with regard to material composition, installation, and performance of coatings. Some steel pipe manufacturers have made significant investment in developing the ability to install this type of product as a lining system and product manufacturers are continually working to improve their products, including epoxy lining systems, for steel pipeline application. Because SNWA is committed to providing high quality and reliable service to its customers, it developed an independent test program, designed by a committee of industry professionals, to address the suitability of these alternative lining systems for steel water transmission pipelines.

The test program and the performance characteristics deemed critical to assess the useful life expectancy of polyurethane and epoxy lining systems are described in this paper. The test program provided an abundance of data on the performance characteristics of five (5) polyurethane lining systems and two (2) epoxy lining systems produced by various manufacturers. Overall lining system performance was based upon the program data as a whole as opposed to individual test data. That is, the purpose of the program was to provide data upon which an opinion could be based as to the viability of using polyurethane or epoxy linings.

Subject
Test methods, Water, Coatings, Vapors, Disbondment, Polyurethanes, Coating adhesion, Erosion, Steel, Rust, Immersion, Cracking, Lining
© 2011 Association for Materials Protection and Performance (AMPP). All rights reserved. This work is protected by both domestic and international copyright laws. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means (electronic, mechanical, photocopying, recording, or otherwise) without the prior written permission of AMPP. Positions and opinions advanced in this work are those of the author(s) and not necessarily those of AMPP. Responsibility for the content of the work lies solely with the author(s).
2011
Association for Materials Protection and Performance (AMPP)
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