API Std 650 storage tanks impact tests

The {keyword shell that contains the liquid shall have butt-welded annular bottom plates with a radial width that provides at least 24 in. between the inside of the shell and any lap-welded joint in the remainder of the bottom and at least a 2-in. projection outside the shell. The stated values apply to full-sized specimens. For sub-size specimen acceptance criteria, see ASTM A20. An impact test temperature lower than the design metal temperature may be used by the API 620 large welded, low pressure storage tanks Manufacturer.

Supply covers for API Std 650 storage tanks connections specified with the service covers remaining in place following tests. For API 650 tank connections not specified to be supplied with service covers, the test covers may be removed after testing.

Natural ventilation loss: the main cause of natural ventilation loss is that the API Std 650 storage tanks is not tightly sealed. This is usually due to corrosion perforation on the top of the oil tank, or there is a height difference between the two orifices. The air tightness of the mixture in the API Std 650 storage tanks is higher than that of the air, which causes the mixture gas in the tank to be discharged into the atmosphere from the lower hole, and the external air flows into the tank from the high hole, resulting in natural ventilation loss.