Tank Bottom Plate Extension Evaluation per API 653;
Many people have seen the outer protrusion of the Tank
Bottom of the Atmospheric Aboveground Storage Tank, which according to API standard is
called bottom plate extension corrosion, causing the thickness to be reduced and shortening
the distance protruding from tank shell. Must be more than 2.5 mm (0.1 in.) thick and
must protrude outside the body of shell at least 10 mm (3/8 in.) measured by welding paws
(Weld toe)
Therefore, if the Bottom Plate Extension is found to be corroded, be sure to measure
the thickness and filing distance. If you are still in acceptance criteria according to API 653.