Nominal diameter of API 650 duplex stainless steel tanks

Under the condition of static storage without receiving and sending operation, the temperature of gas space, evaporation rate, depth and pressure of vapor in the API 650 duplex stainless steel tanks will change with the change of temperature and pressure in a day. The oil loss caused by the process of discharging oil vapor and inhaling air gas is called "small breathing" loss, which is also called static storage loss of oil tanks.

The tank 20-in. inside-diameter nozzle shown in Figure F-6 is located in solid plate in the sidewall of a cylindrical storage tank 148 ft in diameter in an area where the thickness of the wall plate, tw, is 11/2 in. A corrosion allowance of 0.10 in. is required on all surfaces of the tank exposed to the stored liquid. The total internal pressure, Pl + Pg, at the center of the opening is 24.9 lbf/in.2 gauge. The thickness of the API 650 duplex stainless steel tanks wall plate, t, required by 5.10.3 for the latitudinal unit forces, T2, acting at this level is 1.44 in.

Floating roofs shall comply with API standard 650, Appendix C (Attachment 01) or with the API 650 duplex stainless steel tanks requirements as layed (laid )down in the national Chinese specifications SH3046-92 and GBJ128-90.