Development of technology to inspect gas distribution mains during operation. Final report (task 0-4), January 1995-December 1995

The report investigates the feasibility of adapting commercial magnetic flux leakage (MFL) transmission pipeline inspection systems to small diameter gas distribution mains. The investigation encompassed technical challenges required for implementing MFL within the gas main environment. These included component miniaturization, ability to attain meaningful pipe wall thickness measurements and identification of external and internal defects with an air gap between the magnet poles and the pipe wall, conveyance systems for moving the inspection device, tapping of the gas main and restoration of the main to its original mechanical competence. Conclusions of the research and recommendations for future work are provided.