The use of the Electro-Magnetic Acoustical Transducer (EMAT) technology for crack detection by In-Line Inspection (ILI) tools has become more promising over the last few years. Rigorous validation of the technology leading from the initial application of EMAT inline inspection tools through to determining ILI tool Probability of Detection (POD) and Identification (POI) contributes to an improved confidence and reliability. The EMAT results are then utilized to determine SCC valve section severity, to review and modify hydrostatic test schedules and intervals and could potentially be implemented as a viable alternative to hydrostatic testing.
This paper describes the development of an EMAT ILI based program and the related validation process applied by the vendor, pipeline operator and in-ditch personnel. This process will be illustrated by demonstrating the performance of the EMAT tool in two 20” diameter natural gas pipelines which have a documented history of SCC.