API standard 650 insulated tanks for small internal pressures

Due to irregular operation of API standard 650 insulated tanks welding, there are many weld deformations during the construction process. Before specific operations, most construction units have formulated relatively complete construction plans and set up special welding process instructions, but the operators have not fully performed welding in accordance with various process guidance requirements and construction specifications, resulting in some quality problems of oil storage tanks. How can we reduce or even avoid this kind of situation?

Investigation of Subgrade
On actual steel storage tank sites to be used, test borings or test pits, or both, may be made at the direction of a competent engineer who will specify the number and location. They need not be equally spaced but should be laid out to uncover possible weak spots.
In general, test loadings of subgrade at the bottom of test pits need be resorted to only when such heavy loading as may be imposed by footings for major column supports for spheres or similarly elevated API 620 low-pressure tanks is specified. Results may be deceptive if average load-bearing capacity over a considerable area is wanted. All field data shall be recorded with maps, and copies shall be supplied to all engineers concerned with design, erection, and later operation.

This API 650 tank standard does not present orstablish a fixed series of allowable tank sizes: instead, it s intended to permit the purchaser to select whatever size API standard 650 insulated tanks tank may best meet his needs.