[2C2] In-service inspection of external corrosion scabs: updated HOIS/NZTC guidance
M Jones and S Burch
ESR Technology Ltd, UK
External corrosion of pipework is a significant issue for asset owner/operators. The HOIS joint industry project, supported by the Net Zero Technology Centre, has performed multiple inspection trials to develop guidance for the in-service determination of the minimum remaining ligament under external corrosion scabs on live lines where it is hazardous to remove the corrosion product to obtain direct access to the underlying steel.
This paper will highlight recent updates to the publicly available guidance, including: analysis of the performance of selected NDT techniques in determining the minimum remaining ligament under scabs where the corrosion morphology includes localised pitting; the use of double-wall single-image radiography in determining the presence of isolated pits under external corrosion scabs; and the use of photogrammetry and laser scanning for determining profiles of external corrosion scabs to aid interpretation of DWSI radiographs.
Keywords: inspection, digital radiography, ultrasonics, eddy currents, corrosion.
This paper will highlight recent updates to the publicly available guidance, including: analysis of the performance of selected NDT techniques in determining the minimum remaining ligament under scabs where the corrosion morphology includes localised pitting; the use of double-wall single-image radiography in determining the presence of isolated pits under external corrosion scabs; and the use of photogrammetry and laser scanning for determining profiles of external corrosion scabs to aid interpretation of DWSI radiographs.
Keywords: inspection, digital radiography, ultrasonics, eddy currents, corrosion.
