The Brief

Perform a routine inspection of a 19.51m storage tank pre the application of insulation paint.

What We Proposed

Remove tank lagging and check for Corrosion Under Insulation.

What We Delivered

The lagging was removed from a 19.51m storage tank so a routine inspection could be carried out and insulation paint applied. It was quickly apparent during the lagging removal process that the tank was suffering from a mixture of Corrosion Under Insulation (CUI) and corrosion in the internal vapour space of the roof.

Multiple holes were visible from floor level and welds were splitting due to the extent of corrosion. As it wasn’t practical for technicians to walk on the roof, we used our automated Scorpion B-Scan to scan the roof from the centre to the edge in an array pattern. A minimum reading of 1.0mm was found on the plates which have an assumed nominal thickness of 5.0mm. Technicians were attached to an inertia reel and visually inspected the viewing area at the North West of the tank. Holes were evident in this area and a chipping hammer was used to determine the extent of corrosion.