Use of magnetic flux leakage (MFL) for the inspection of pipelines and storage tanks

Vetco Pipeline Services, Inc. (VPSI) has been using the magnetic flux leakage (MFL) technique to inspect operating pipelines and above ground storage tanks for many years. This technique involves magnetically saturating the material under inspection and scanning the surface of the material for MFL fields caused by wall thinning defects. Recently, VPSI has adapted this technology for the inspection of in-service distribution pipelines. This new inspection system couples the MFL techniques used for pipeline inspection to a novel delivery system for the specific task of gathering real time data on the condition and integrity of distribution pipelines. The focus of this paper is to review this application of the magnetic flux leakage technique to describe the novel delivery systems developed and to detail the enabling technologies that now allow real time capture and analysis of inspection data.