Detection of Corrosion in Offshore Risers Using Guided Ultrasonic Waves

Guided wave ultrasonics is now an established technology for detecting corrosion in pipes. The technique is principally applied to pipe that is insulated, buried or otherwise inaccessible to conventional NDT. TWI has experience in applying the technique to offshore risers, where there are specific problems. Access beneath the cut-off valves of the platform is restricted and the clamps used to hold the riser and the coatings used to protect it in the splash zone can affect test performance. This paper will describe these problems in detail and discuss ways of overcoming them. Case studies will be used to illustrate the current state-of-the-art and TWI’s research and development programme in long range ultrasonics for inspecting a wide range of components from pipes to railway lines will highlight future developments.