What factors affect the design pressure of a pressure vessel?

1. Safety relief device factors
Whether the container is equipped with a relief device and the type of device directly affect the value:

‌Safety valve‌: The design pressure shall not be lower than the opening pressure of the safety valve
‌Bursting disc‌: The design pressure is not lower than the sum of the bursting pressure of the bursting disc and the upper limit of the manufacturing range
The pipeline locations are different: the safety valve installed on the outlet side pipeline needs to superimpose the pipeline pressure drop, and the inlet side needs to take the maximum value of the two working conditions.
2. Media characteristics and process factors
Liquefied gas container: The design pressure without cold insulation facilities is not less than the 50℃ saturated vapor pressure of the medium. If the component is uncertain, the corresponding component 50℃ saturated vapor pressure shall be taken.
Pump inlet and outlet containers: When there is no safety device on the pump inlet side, the pump lift parameters need to be superimposed, and the maximum value of the three working conditions must be taken, and the external pressure bearing capacity must be checked at the same time.
A safety margin needs to be left: pressure fluctuations during operation need to be considered. The design pressure is calculated according to the formula = maximum possible working pressure + safety margin + static pressure difference + process fluctuations
3. Container structure and working conditions factors
‌Liquid column static pressure‌: When the liquid column static pressure reaches 5% of the design pressure, the design pressure needs to be the sum of the design pressure and the liquid column static pressure.
‌External pressure/vacuum vessel‌: The design pressure is not less than the maximum internal and external pressure difference for normal operation; the design pressure of the vacuum vessel without safety device is 0.1MPa
‌Jacketed vacuum vessel‌: The design pressure is the vacuum vessel requirement plus the design pressure inside the jacket
4. Special requirements for device types
Mobile pressure vessels also need to meet the minimum threshold requirements for filling and unloading conditions; when the system has a control device but a single container has no control and the pressure drop is unclear, the design pressure needs to be determined based on the working pressure range by looking up a table.

5. Standard and normative factors
The design pressure value must meet the requirements of mandatory standards such as GB150 "Pressure Vessels" and "Safety Technical Supervision Regulations for Stationary Pressure Vessels", and the value must not be less than the maximum working pressure of the vessel.