API 650 self-anchored storage tanks double-flanged nozzles

Static storage loss is also known as "small breathing" consumption. The rise and fall of the temperature in the API 650 self-anchored storage tanks leads to the increase and decrease of the pressure in the tank, which makes the mixed oil gas discharged from the tank, and the external air is sucked into the tank, resulting in the oil consumption. Fluid level loss is also called "big breathing" loss. It is the oil consumption caused by the change of gas space volume in the API 650 self-anchored storage tanks during the oil receiving and sending operation, which causes the mixed oil gas to be discharged out of the tank, and the external air is sucked into the tank, resulting in the oil consumption due to the change of liquid level height.

The thickness of the API 650 self-anchored 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.

While GB50341 generally takes the weld coefficient as 0.9;When the minimum yield strength of API 650 self-anchored storage tanks steel plate is greater than 390 MPa, take 0.85. The thickness of API 650 tanks is generally smaller than that of GB50341, and this difference is particularly evident in the design of large tanks, where the overall weight of the tanks varies greatly.