EXTERNAL CORROSION DIRECT ASSESSMENT (ECDA) FOR ABOVEGROUND STORAGE TANK BOTTOMS

摘要

Direct assessment (DA) has been effectively used to evaluate the integrity of external aboveground storage tank (AST) bottoms. When cathodic protection (CP) is applied to the external surfaces of the AST bottoms, the corrosion rate can essentially be set to zero, per American Petroleum Institute (API) 653, extending the tank internal inspection intervals up to 20 years (1). AST bottoms have a practical limited time when they can be assessed. DA of AST bottoms will greatly improve the chances of detecting and preventing corrosion failures prior to the next scheduled internal inspection.