API 650 unanchored tanks limitations

API 620 Crude Oil Tank Pneumatic Pressure
An air pressure equal to 1.25 times the pressure for which the vapor space is designed shall be applied to the enclosed space above the water level. In the case of a double-wall tank with an open-top inner tank, where the air pressure acts against the outer tank and the inner tank is thus not stressed by the air pressure, the inner API 650 unanchored tanks may be emptied of water before the pneumatic pressure test begins. The test pressure shall be held for 1 hour.Welding certification is regulated by Section 10 of the American Society of Mechanical Engineers (ASME). For both API 650 unanchored tanks storage tank API 650, non-destructive inspection is required, but third-party inspection is not required.In November of 2015, Thailand one company contacted with us from Internet. They are find the trustable supplier of S355J2H seamless pipe API 650 unanchored tanks for there cable car supporter. Due to the special using of the pipes, they are very careful and servious when choosing the supplier. After one months contact and discussion by email, they come to our company. We drive to the pipe mill for visit of 2 days. Through this visit, they are very confident with our production ability and proucts quality. Finally, they accept the grade we suggest Q345D. After back to office, they put the order of 1400 tons pipe to us directly.The bottom plate of the vertical API 650 unanchored tanks directly contacts with the foundation soil, which is suitable for the flexible foundation, and its settlement characteristics are quite different from that of the rigid foundation. For the settlement calculation of the foundation of a vertical API 650 unanchored tanks, the one-way compression layered sum method can be used. The calculation method is to divide the foundation soil into several layers of compression within the calculation depth of the foundation settlement, and then find the sum. The calculation method of the compression amount of each layer is the same as the calculation method of the compression amount under the condition of no lateral deformation.The after-sales service department will pay return visit to each customer by call or email, report problems found during the return visit in time, and discuss with the production and quality inspection center to propose effective solutions and follow up in a timely manner, so as to ensure the benefits each customer are fully guaranteed, and to provide customers with more value-added services.