API Std 650 cylindrical welded storage tanks decks

API Std 650 cylindrical welded storage tanks Liquid Relief ValvesA tank, which is likely to operate completely filled with liquid, shall be equipped with one or more liquid relief valves at the top of the roof, unless otherwise protected against overpressure. When such valves are, in effect, supplementary relief devices, they may be set at a pressure not greater than 1.25 times the design pressure. Because the relief valve at the pump, which provides the inflow of liquid to the tank, is set at a pressure greater than 1.25 times the design pressure of any tank that may be built under these rules, provision should be made for preventing overfilling of the tank by a self-closing float valve, by some practicable pilot-valve control, or by any other proven device.

According to API 650 tanks, anchoring devices should be designed to transfer overturning moments to the API Std 650 cylindrical welded storage tanks tank foundation. At the same time, according to API 650 tank Appendix F, when the tank is to be anchored, the size of the anchoring parts is determined by the maximum lifting force caused by the internal pressure and wind load or the combination of internal pressure and seismic load.

Treatment of API Std 650 cylindrical 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.