Defect Detection in Water Pipelines Using Ultrasonic Guided Waves

The integrity of water piping infrastructures is essential for providing safe drinking water and for the treatment of wastewater. As pipelines age, they deteriorate, corrode, and crack. Existing techniques, such as visual observation and closed circuit TV, for assessing piping integrity are expensive and have difficulty accessing particular regions of piping structures. Ultrasonic guided waves, on the other hand, have the capability of penetrating multi-layered structures, such as pipes with concrete linings. This makes it possible to detect defects under concrete lining that can be difficult to find using visual observation and closed circuit TV. Another associated problem is axial crack detection in large diameter water pipes. Ultrasonic guided waves propagating in pipe circumferential directions have an innate sensitivity to axial cracks. During the Phase 1 portion of this project, we demonstrated the feasibility of axial crack detection using circumferential guided waves and defect detection in a concrete lined pipe using axial guided waves. In Phase II, we will focus on the development of two prototype systems. One is a circumferential guided wave tool that is capable of detecting axial cracks by traveling through the inside of a steel water pipe. The other combines guided wave focusing techniques with the recently developed magnetostrictive sensors for defect screening of concrete lined water lines. Magnetostrictive sensors are flexible, robust, light-weight, and low cost. They are also capable of producing strong guided wave energy in pipelines. FBS has extensive experience with piping defect detection using long range ultrasonic guided waves; acquired through ONR, DOT, and EPRI sponsored work. We recognize the need for reliable, economic, and safe inspection solutions for the maintenance and assessment of water piping. The proposed work builds on FBS accomplishments to date. The work is dedicated to an economic implementation of the proposed inspection method(s). We believe that the "intelligence" necessary to develop the two prototype systems can be bundled into a hand held device interfaced with a compact ultrasonic package and/or with a commercially available platform [Pipe Inspection Gear, or PIG) that travels inside water pipes.