A662 Gr B plates API standard 650 flexible liquid storage tanks

The API 620 large storage tank nozzle neck is fabricated by welding from 1/2-in. plate. The materials in the tank wall, the nozzle neck, and the reinforcing pad conform to ASTM A442 Grade 55. The main joints in the tank wall are fully radiographed, double-welded butt joints. The longitudinal joint in the nozzle neck is of the same type API standard 650 flexible liquid storage tanks but is not radiographed; however, the longitudinal joint and all other parts of the nozzle-and-wall-plate assembly have been shop stress relieved after fabrication, as required by 5.25. The adequacy of the reinforcement and attachment welds shown in Figure F-6 shall be determined.

Application scope of API 650 petroleum storage tank:
1. API standard 650 flexible liquid storage tanks Working pressure: atmospheric storage tank;
2. API 650 petroleum storage tank working temperature: -30℃～150℃;
3. API 650 petroleum storage tank liquid medium: various oil products, including naphtha, gasoline, diesel, kerosene, crude oil, fuel oil, heavy oil, benzene, xylene, methanol, ethanol;
4. API 650 petroleum storage tank volume: current design considerations generally do not exceed 10,000 cubic meters.

According to the structure type of floating roof, floating roof API standard 650 flexible liquid storage tanks can be divided into internal floating roof tank and external floating roof storage tank. The internal floating roof tank is a floating roof tank with tank roof. The top is the combination of dome roof and floating roof, the external is dome roof, and the internal is floating roof. There is no vault on the top of the External floating roof tank, only a top plate floating with the storage liquid. The common feature of the inner floating roof tank and the outer floating roof tank is that both of them can reduce the evaporation loss of the storage liquid.