Several American Petroleum Institute (API) Standards and Recommended Practices speak directly to the basic need to control corrosion of the bottom, shell, and roof of aboveground storage tanks (ASTs) to assure tank integrity. These documents contain information and requirements related to corrosion that must be considered for new tanks, in their design and construction, and for existing tanks during inspection, maintenance and repair activities. This paper reviews the requirements contained in these documents and presents histories of internal and external corrosion that has occurred in ASTs.
AST corrosion continues to be a critical problem, not only in the petroleum process industry, but in other industries that store corrosive or environmentally sensitive materials or products in aboveground tankage. In the petroleum industry, AST corrosion is of concern at production, transportation, manufacturing, and marketing facilities. It is the objective of this paper to review several API Standards and Recommended Practices with emphasis on the requirements in these documents related to corrosion and corrosion control. These documents are:
? API Standard 6 5 0 - "Welded Steel Tanks for Oil Storage"
? API Recommended Practice 575 -"Inspection of Atmospheric and Low Pressure Storage
Tanks"
? API Standard 653 -"Tank Inspection, Repair, Alteration, and Reconstruction"
The last two documents contain Inspection Checklists which are useful during external and internal inspection of tanks. These are provided as guidance for owners and operators in developing an inspection assessment program. Many of the inspection activities included on the checklists are there because of corrosion concerns. API Recommended Practice 575 also contains detailed discussions of corrosion mechanisms associated with ASTs that are accompanied by related photographs.
