The Scope of the API 653 Standard is limited to the following tank components: foundation,tank bottom, shell, structure, roof, and nozzles to the face of the first flange. When a physical modification to the tank is required, an assessment of the future integrity of the tank will be performed. The main factors that must be taken into account
during the tank integrity evaluation the ones associated with the stored product, the environmental conditions, materials, live loads, foundations, distortions of the existing tank, etc.