SI units API Std 650 unanchored liquid-storage tanks

API 620 Tank Design
The designer of these large tanks API Std 650 unanchored liquid-storage tanks shall supply the data on superimposed loadings to be assumed for the foundation design or, if there are no foundations, for direct loading on the subgrade. A slab or mat may be provided to support the superstructure and shall be considered to distribute the load more evenly over a lower natural subgrade compared with merely stripping, leveling, and rolling the existing grade.
For simple spheroids or tanks of similar design, in which the distribution of the imposed weights shifts because the liquid level in combination with the vapor pressure may change the shape of the tank, the designer shall consider the possibility of such a change.

API 650 is an American standard for welding flat bottom vertical storage tanks. This API Std 650 unanchored liquid-storage tanks standard specifies requirements for the design, manufacturing, welding, inspection and installation of storage tanks. API 650 is widely used in storage tanks designed to withstand low internal pressures and used to store typical products such as API Std 650 unanchored liquid-storage tanks crude oil, gasoline, chemicals and water. BBN has extensive experience in API 650 tanks, from +/- 500 cubic meters of tanks produced in the factory to +/- 15000 cubic meters of tanks produced on site.

Crack treatment of API Std 650 unanchored liquid-storage tanks weld area: find out the crack tip with ray or ultrasonic flaw detection, drill cut-off holes at both ends of the crack with the cut-off method, the hole depth is slightly greater than the crack depth, or groove (crack stop groove) is made by angle grinder at both ends of the crack, shovel and grind the whole crack, and grind it into a suitable groove; use radiographic inspection and dye detection to verify that the crack has been completely excavated, and finally repair welding.