Mechanical loads on API standard 650 aboveground welded storage tanks

Inspection of Welded storage tanks Surfaces Exposed during FabricationThe edges of API standard 650 aboveground welded storage tanks plates, openings and fittings exposed during fabrication shall be inspected carefully to make sure that any defects have been uncovered, as well as to determine that the work has been performed properly.Minor defects found may be repaired only after the inspector approves the method and extent of repairs. Materials that have more than minor defects that cannot be satisfactorily repaired shall be rejected.Spot radiographic or ultrasonic examination shall be not less than 6 in. extending along the weld. Spot radiography shall comply with the standards given in 7.15.1.3. Where spot radiographic or ultrasonic examination is applied at joint intersections, the surface shall be prepared and examined for a distance of 3 in. on each side of the intersection, making the minimum length of examination 6 in. on the horizontal weld and 3 in. on the vertical weld.

There is a gap of 100 mm to 500 mm between the shell of API 650 crude oil storage API standard 650 aboveground welded storage tanks tank and the floating plate of external floating roof to ensure that there is no chuck during operation. Use API standard 650 aboveground welded storage tanks edge sealing system to reduce edge evaporation. The support legs of API 650 crude oil tank floating roof are usually movable and retractable and suspended in liquid.

Treatment of API standard 650 aboveground welded storage tanks welding defects:
1. Lack of fusion: once found, it should be shoveled and grinded off before re welding.
2. Incomplete penetration: over standard defects shall be removed and re welded. When welding on both sides, the shallow side of the groove can be grinded and shoveled to expose the welding root on one side, and then the welding is repaired.
3. Slag inclusion: over standard defects shall be removed and re welded.
4. Crater: weld to full after grinding.
5. Air hole: if the internal air hole exceeds the standard, it shall be welded again after being removed by grinding shovel, and the surface air hole shall be removed by grinding wheel and then repaired.