API 653 case studies
API 653 · Put your knowledge to work in context.
API 653 is the American Petroleum Institute's certification for aboveground storage tank inspectors. API initiated the program with the participation of storage tank owners and users, establishing a uniform national program that assists state and local governments in aboveground storage tank regulations. The API 653 case studies are 5 cases and about 3,902 words.
1Bottom Course Below t_min: Repair, Replace, or Rerate the Fill Height?
A 60 ft diameter x 40 ft shell-height fixed-roof tank was built in 1963. There is no nameplate, no radiography record, and the material is assumed to be A36; the owner's engineer has authorized S = 23,200 psi and E = 0.70.
779 words, about 4 min2Setting the Next Internal Inspection Date from Two UT Surveys
An 80 ft diameter x 48 ft high tank stores product of G = 1.0. Its shell butt welds were fully radiographed at construction, so E = 1.0, and the authorized allowable stress is S = 25,000 psi.
725 words, about 4 min3New Manway, Gasket, and Weld Build-Up in One Outage: Classification Drives Everything
An existing 45 ft diameter x 32 ft high tank in gasoline service (G = 0.75) needs three items in the same outage: a new 24 in. shell manway cut into the second course about 12 ft above the bottom; a gasket replacement on a leaking 6 in.
793 words, about 4 min4Leaking Shell Pit at 30 Inches: Can the Tank Stay in Service?
An operator finds a persistent gasoline weep at a shell pit 30 in. above the shell-to-bottom weld of an 80 ft diameter x 40 ft high fixed-roof tank holding 22 ft of product (G = 0.74).
816 words, about 4 min5Relocating a 1950s Tank With No Records
A 100 ft diameter x 40 ft high fixed-roof tank came with a terminal purchased in 2022. It has been out of service since 2018, is empty, and the shell manway has stood open for four years.
789 words, about 4 min