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18 May 2012 Infrared evaluation of insulated pipelines to detect water that could cause Corrosion Under Insulation (CUI)
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IR (infrared) inspection is being used to inspect oil pipelines on the North Slope of Alaska. The object of this inspection is to detect water trapped in the foam insulation around the steel pipes before it can cause corrosion that could result in a pipeline leak. This is referred to as Corrosion Under Insulation (CUI). The same method can be used to inspect insulated pipelines containing LNG (liquid natural gas), steam, heated chemicals, cryogenic fluids, etc. As long as the temperature in the pipe is substantially different (+ or -) than the ambient temperature, the IR evaluation method can work. Analysis can predict whether it will work for a specific application and operating conditions. IR can scan multiple pipes quickly and is a good qualitative screening method for detecting water trapped in insulation. Anomalies found by IR are evaluated further using RT ("C-Arm" or other RT technique) or other NDT methods. RT is a relatively slow technique compared to IR, but it is capable of detecting both water and pipe wall thinning. When the water level is high enough to reach the steel pipeline, corrosion of the pipe can occur. In this case, the corrosion is from the outside of the pipe inward. Other corrosion and erosion may take place from the inside out. Corrosion and erosion can eventually result in a hole in the pipe, which results in a leak. Thermal modeling has been performed to predict the environmental conditions under which IR testing will be successful. IR test procedures have been written and a personnel certification program has been implemented.
© (2012) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Douglas Burleigh and H. Allen Sanders "Infrared evaluation of insulated pipelines to detect water that could cause Corrosion Under Insulation (CUI)", Proc. SPIE 8354, Thermosense: Thermal Infrared Applications XXXIV, 83540P (18 May 2012);

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