The lowest design temperature of API 650 ground supported liquid storage tanks

Prefabricating API 650 ground supported liquid storage tanks components before construction can improve construction efficiency, save time and cost, and is currently a common method for the construction of large vertical storage tanks. The main prefabricated components of a large vertical API 650 ground supported liquid storage tanks include the tank body, the storage tank wall, the top of the storage tank, the bottom of the storage tank, and the accessories of the storage tank. The prefabrication of the components should follow a reasonable workflow, and carry out appropriate heat treatment and testing, so as to improve manufacturing accuracy.

The thickness of the API 650 ground supported liquid storage tanks wall plate, t, required by 5.10.3 for the latitudinal unit forces, T2, acting at this level is 0.57 in. The nozzle neck is seamless steel pipe and conforms to ASTM A53, Grade A; the materials in the tank wall and reinforcing pad conform to ASTM A442 Grade 55. The main joints in the tank walls are fully radiographed, double-welded butt joints. The adequacy of the reinforcement and attachment welds shown in Figure F-7 shall be determined.
To determine the length of the nozzle neck within the limits of reinforcement, the smaller of the following calculated values shall be used:(2.5)(0.625) = 1.56 in.
(2.5)(0.375) + 0.75 = 1.69 in.

Corrosion allowance, if specified, shall be added to calculated API 650 tanks shell and self-supporting roof thicknesses; to minimum nominal thicknesses of bottom and supported API 650 ground supported liquid storage tanks roof plates; to nozzles and manholes; and to all exposed surfaces of internal structural members and non-removable internals.