Regarding safety valves for pressure vessels
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Seeking advice: Can the setting pressure of the safety valve on a pressure vessel exceed the design pressure? According to which standard can it be determined?
It generally does not exceed the design pressure. Sometimes, the diagram shows the maximum allowable operating pressure as well as a design pressure; in such cases, the setting pressure of the safety valve exceeds the design pressure. The design pressure no longer holds any meaning at this point. The actual design pressure is already the maximum allowable operating pressure.
The set pressure must not exceed the design pressure; this is a basic requirement specified in the safety regulations for safety valves. I was educated by the special inspection team on this issue this year.
In that case, if the pressure exceeds the design value, does it mean the setting pressure of the safety valve needs to be adjusted again?
No, it’s usually 1.1-1.15
If the setting pressure of the safety valve exceeds the design pressure, how can it still serve its safety function? :lol
The current design pressure does not require a reset. The pressure of the new design is higher than the original safety valve opening pressure. That solves it
When the equipment specifies a maximum allowable working pressure (MAWP), the set pressure is less than the MAWP but can be greater than the design pressure; this approach is often used when the equipment needs to be airtight
It generally shall not exceed the design pressure. If the design specifies a maximum allowable operating pressure, the set pressure shall not be higher than this maximum allowable pressure (it may be higher than the design pressure)
The Fixed Volume Code specifies that the pressure for the airtightness test shall be the design pressure. It also states that for pressure vessels equipped with overpressure relief devices such as safety valves, if an airtightness test is required, these safety accessories must be properly installed, and it specifies that the designer shall determine the maximum allowable operating pressure. Well, it’s very clear now.