Fabrication requirements for API 650 unanchored tanks
Usually, the soil resistance of the foundation should be considered before the design and construction of API 650 unanchored tanks. The soil endurance in the API 650 unanchored tanks construction area plays a decisive role in the basic cost of the tank. In areas with high soil resistance, not only the cost of foundation treatment can be greatly reduced, but also the ratio of height to diameter of storage tank can be obtained. Therefore, the investment cost of the API 650 unanchored tanks can be greatly saved in the area with large soil resistance.
Structural shapes of 9% and 5% nickel steel may be furnished to the chemical and physical requirements of ASTM A353, A553, or A645. Physical tests shall be in accordance with the requirements of ASTM A6.API 650 unanchored tanks used Piping, Tubing, and ForgingsMaterial used for piping, tubing, and forgings shall be compatible in welding strength, and thermal expansion coefficient with the tank shell material. In addition to the specific requirements of this appendix, all piping within the limitations of 1.3.2 shall fulfill the minimum requirements of ASME B31.3.
When API 650 storage tank is designed, when the design pressure is small F2 kPa, the impact of air pressure on the API 650 unanchored tanks tank wall thickness is not considered in the tank wall design.
