API standard 650 flexible liquid storage tanks designers

X-ray inspection is mainly applicable to the internal inspection of pressure bearing parts and materials of metal oil tanks such as API standard 650 flexible liquid storage tanks. It can clearly find the blocky defects inside the welded joints. However, the cost and resource consumption of radiographic testing are large. Magnetic particle testing can effectively detect the surface and near surface defects of API standard 650 flexible liquid storage tanks etc. metal oil tanks, but magnetic particle testing can not effectively identify the internal defects of oil tanks.

Soil Structure Interaction: Soil structure interaction per API 650, Section E.6.1.6 may be used for OLE design providing the damping ratio does not exceed 10 %.
Allowable Stresses
Design allowable stresses shall be per API 620 large welded steel storage tank, Section Q.3.3, including the 33 % increase permitted for earthquake loads.
Self-anchored Inner Tank
The anchorage ratio for a self-anchored inner tank, J, shall not exceed 1.0 for the OLE design combination to limit uplift and stresses in the annular plate and corner weld.
Foundation Stability
The overturning ratio defined in API 650, Section E.6.2.3, Equation (E.6.2.3-1) shall be equal to or greater than 3.0 for the defined OLE event.

API 650 tanks in which liquid fluids are stored and designed to withstand atmospheric pressure operation, less than 18 kPa, or internal pressures not exceeding the weight of the API standard 650 flexible liquid storage tanks roof, with temperatures no higher than 93, 3 C are included in the scope of this design code.