A review of the state-of-the-art in composite repair technology.

Author:Alexander, Chris

Over the past 25 years, the gas and liquid transmission pipeline industry has integrated composite repair systems into their integrity-management programs. In the early stages of this process, the composite repair technologies were rather limited; however, over the past decade there has been a proliferation of composite repair technologies introduced to the market.

Their introduction has been accompanied by extensive research efforts funded by both operators and composite repair companies well in excess of $15 million. This has been an exciting season in the pipeline industry as we have witnessed a partnership between pipeline operators, technology companies, research organizations, and regulators to advance the composite repair state-of-the-art built on rigorous engineering-based assessment techniques involving analysis and testing.

The purpose of this article is to provide an overview of advances in composite repair technology focused primarily on the gas and liquid transmission pipeline industry in the United States. It should be noted that several UK-based organizations have developed and evaluated composite repair systems used mainly in the North Sea; a discussion on these efforts is considered to be outside the scope of this article. Further, composite repair technologies are frequently used to reinforce process piping in refineries and chemical plants; however, for the most part, these installations are employed to reinforce relatively low pressure piping systems.

Worldwide, more than 15 companies manufacture composite repair technologies for the pipeline industry. Furthermore, most of these companies offer multiple repair systems, so that the total number of systems available to operators easily exceeds 50. The benefit for industry is that a wide range of technologies are available to reinforce an array of anomalies, fittings, and features. The challenge for the pipeline industry is to ensure that the composite technologies perform as designed. The good news is that industry has risen to the challenge, as documented in several of the case studies presented in this article. Organizations such as the Pipeline Research Council International, Inc. (PRCI) have been instrumental in this process.

Each composite repair system comprises relatively few components (i.e., the load-transfer material and the composite material itself); however, each component serves a critical role to ensure that the repair system performs properly. Once the pipe has been inspected and the severity...

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