A737 Gr B plates API standard 650 welded tanks for oil storage

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 welded tanks for oil storage 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.

The calculated thickness of the above-mentioned wall panels required by the hydrostatic pressure is also It API standard 650 welded tanks for oil storage should be increased by the same ratio, unless special analysis is performed to determine the seismic overturning moment and the corresponding stress at the bottom of the wall of each layer of API 650 tank.

The cleanliness of the API standard 650 welded tanks for oil storage has a great influence on the safety of the tank and the quality of the oil stored. Keeping the API standard 650 welded tanks for oil storage clean can slow down the corrosion of the tank wall and reduce the pollution to the oil. If the inside of the API standard 650 welded tanks for oil storage is not cleaned all the year round, a lot of rust and metal impurities will be produced in the tank. These impurities will cause the oil to slowly oxidize and deteriorate. The impurities mixed into the oil will also block the filter and oil circuit, causing oil supply failure.