API 650 carbon and low-alloy steel tanks leg lengths

Welding inspection of bottom plate of API 650 carbon and low-alloy steel tanks, vertical oil tank: During the fabrication and installation of API 650 carbon and low-alloy steel tanks, the bottom edge plate is welded first. According to the requirements of the technical standard, penetrant inspection is required for the weld of edge plate at the bottom of API 650 carbon and low-alloy steel tanks, that is, penetrant testing is required for each weld bead priming, filling and capping. In the process of testing, if any defect is found, it shall be repaired immediately. After the repair, the surface coloring penetrant test shall be conducted again until the test result is qualified.

When the anchorage is designed to meet the requirements of API Standard 620 tank Q.3.6.4.2, the foundation should be designed to resist the uplift that results from three times the design pressure with the tank full to the design liquid level. When designing to any of the conditions in this paragraph, it is permissible to utilize friction between the soil and the vertical face of the ringwall and all of the effective liquid weight.

Under the same sealing effect, the internal floating roof tank of API 650 oil storage tank can further reduce the evaporation loss compared with the API 650 carbon and low-alloy steel tanks External floating roof tank. This is due to the shielding of the fixed roof and the gas layer between the fixed roof and the internal floating plate, which has more significant heat insulation effect than the double disc floating roof of the API 650 carbon and low-alloy steel tanks external floating roof tank.