A516 Gr 415 plates API standard 650 aboveground welded storage tanks

Shell Stiffening Rings for Tanks That Contain Liquid
Internal or external shell stiffening rings may be required to maintain roundness when the tank is subjected to wind, vacuum, or other specified loads. When API standard 650 aboveground welded storage tanks stiffening rings are required, the stiffener-to-shell weld details shall be in accordance with Figure Q-1 and Q.3.5.2 through Q.3.5.5.
Three-plate laps or butt-weld junctions in tank bottoms shall be not closer than 12 in. from each other or from the butt-welds of the annular plates.
Bottom plates, other than annular bottom plates for a 9% or 5% nickel steel or stainless steel tank that contains liquid, may have a minimum thickness of 3/16 in. exclusive of any specified corrosion allowance.

Fixed roof API 650 oil storage tank includes inner floating roof tank, which API standard 650 aboveground welded storage tanks can effectively prevent sand, rain, snow or dust from polluting the storage liquid. Under various weather conditions, API 650 oil storage tank can ensure the quality of liquid storage, which is called "all-weather API standard 650 aboveground welded storage tanks storage tank".

The specifications used in the design of large oil tanks, API standard 650 aboveground welded storage tanks mainly include American Petroleum Institute Standard API 650, Japanese Industrial Standard JIS B8501, British Industrial Standard BS2654 and Chinese National Standard GB50341 from a global perspective. The formulas used in each specification are based on the hoop stress in the membrane theory. Each specification is based on the performance characteristics of materials and the construction technology level of their respective countries to determine the allowable stresses and weld coefficients. Therefore, the calculation results of tank wall thickness of API standard 650 aboveground welded storage tanks with the same volume are sometimes quite different according to different specifications.