Above ground tank owners are increasingly faced with regulations and company standards regarding release prevention and corrosion control. In particular, tank inspections are also required. Many inspections are revealiig that corrosion is taking place and that metal loss has occurred. Corrosion is occurring frequently despite the fact that cathodic protection has been installed and maintained. This paper discusses why corrosion occurs on tanks which appear to have effkctive cathodic protection. Case
histories are presented. Techniques for installing monitoring tubes under in-service tanks are presented as is a discussion of improving cathodic protection monitoring and the mitigation of corrosion. Concepts regarding extending the life of thinned floors through cathodic protection and leak detection per API standards are reviewed. Also, the use of directional drilling for the installation of monitoring equipment and impressed current cathodic protection are covered. Keywords: aboveground
directional drilling, impressed storage tanks, cathodic protection, cathodic protection monitoring, current cathodic protection, release detection