Validation of EMAT In-Line Inspection Technology for SCC Management

TransCanada has a need to manage sections of the pipeline that are susceptible to stress corrosion cracking (SCC) failure by periodically performing hydrostatic testing. Since hydrostatic testing requires a complete service interruption, In Line Inspection technologies (operating in gas pipelines without liquid couplant) are being investigated as an alternate method to managing this hazard. This requirement resulted in a joint technology and tool development project involving GE Energy and TransCanada. The EmatScan^® Crack Detection (CD) tool is designed to detect and size longitudinally oriented external SCC features in gas-filled pipelines. During autumn 2002, the EmatScan^® CD tool was run in a 64 km section of the TransCanada system. In 2003, field correlation excavations were conducted to assess the accuracy of the tool. This paper describes the results from the correlation program conducted to validate GE Energy’ 36 inch (914 mm) diameter EMAT (Electro Magnetic Acoustic Transducer) crack detection tool.