TransCanada PipeLines has been performing periodic hydrostatic pressure tests of natural gas pipeline sections susceptible to stress corrosion cracking (SCC). In 1996, the Canadian National Energy Board (NEB) held a public inquiry into SCC and recommended that industry develop a reliable SCC In-Line Inspection (ILI) tool. This paper describes the TransCanada and PII Pipeline Solutions project to jointly develop a 36 inch (914 mm) diameter crack detection tool based on EMAT (Electro Magnetic Acoustic Transducer) technology. The EmatScan® CD tool is designed to operate in gas pipelines without a liquid couplant. The EmatScan® CD tool will detect and size longitudinally oriented external SCC features. In 2001, testing of the technology has shown that it can distinguish: • insignificant pipe wall features (stringers, laminations and inclusions) from SCC defects; • internal from external pipe wall features. Off-line tests were performed by pulling the tool through a series of pipe spools containing SCC and other pipe wall features. These pipe spools are from two sections of the TransCanada system where PII’s UltraScan® CD tool was run. This joint project to develop a new ILI tool began in early 1997, and will be completed in 2002.

This content is only available via PDF.
You do not currently have access to this content.