scope:

This document sets out the key features required for planning and executing inspection, maintenance and repair works on aboveground, vertical, steel storage tanks.

The descriptions of key tank components that require inspection and/or maintenance, of degradation mechanisms, and of common inspection techniques, are followed by sections describing the probabilistic (risk- and reliability-based) preventive maintenance (PPM) concept and, for each tank component, a detailed description of inspection and repair methods.

Guidance is given on sources of additional information that will assist both continued operation and inspection.

This document mainly addresses atmospheric storage tanks for oil and chemical products (referred to elsewhere in the text as 'conventional' storage tanks). Tanks for refrigerated storage of liquefied gases are covered in Appendix F.