Factors should be considered in designing pressure

1. The vessels which equipped with over pressure discharge device confirm the design pressure according to the annex about over pressure discharge device in GB150”Pressure Vessel”

2. The confirmation of design pressure for those vessels containing liquefied gases according to the possible max metal temperature on working condition.

3. When determining the design pressure of the external pressure vessel, the maximum internal and external pressure differentials under normal operating conditions should be considered.

4. The design pressure determined by external pressure when design the thickness of shell for vacuum tanks. If there is safety control device available such as vacuum relief valves. Design pressure to take from the pressure difference between 1.25 times the maximum internal and external or 0.1Mpa ,whichever is lower. When no safety relief device, take 0.1Mpa as design pressure.

5. The maximum pressure difference between the chambers shall be taken into account when determining the design pressure for a vessel consisting of two or more pressure chambers

6. For containers with different working conditions, the design should be the most demanding conditions, and in the drawings or the corresponding technical documents indicate the pressure of the various conditions