Investigation on nondestructive evaluation of pipelines using infrared thermography

Different kinds of defects in the pipeline heat insulation layer (PHIL), both in the inner and outer sides, and leakage holes of the pipeline, with or without PHIL, are made artificially and studied using infrared thermography. The detectability of the defect in the PHIL and the leakage of the pipeline are investigated and the relationships between the maximum temperature of the defects in the thermal images and the depth and size of the defects in the PHIL are also studied. In addition, the practical inspection work is done to a boiler system of a warship. Both the simulated study in the lab and the practical applications have certified the effectiveness of thermography.