Steel pipe materials for API Std 650 petroleum storage tanks

Uplift on Foundation
For API Standard 620 tanks with an internal design pressure less than 1 lbf/in.2 gauge, the uplift shall be taken as the smaller of the maximum uplift values computed under the following conditions:
a)The internal design pressure times 1.5 plus the design wind load on the shell and roof.
b)The internal design pressure plus 0.25 lbf/in.2 gauge plus the design wind load on the shell and roof.

API 650 petroleum storage tank stipulates that if the thickness of the lower siding obtained by calculating the anti-overturning moment is greater than the thickness of the API Std 650 petroleum storage tanks hydrostatic pressure test (both do not include the corrosion margin), the calculated thickness of the above siding required by the hydrostatic pressure is It should also be increased by the same proportion, unless special analysis is performed to determine the seismic overturning moment and corresponding stress at the bottom of each layer of API 650 petroleum storage tank wall.

Some defects may be found after the regular safety inspection for the API Std 650 petroleum storage tanks. The common API Std 650 petroleum storage tanks defects are: Tank cracks, tank welding defects. The cracks on the base metal, surface and near surface of the tank wall shall be eliminated by grinding with circular arc, and then magnetic particle inspection or re inspection shall be carried out. Cracks in heat affected zone: generally, grinding method is used to eliminate cracks, and magnetic particle or dye flaw detection is used to confirm that there is no crack, and then repair welding or grinding smooth transition.