I have a question regarding the flaw detection and airtightness testing of pressure vessels
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I have a question: We asked a manufacturer to produce a pressure vessel with a design pressure of 17.13 MPa, and we requested that a safety valve be installed, with a setting pressure of 15.7 MPa for that valve； The medium inside the container is deionized water and nitrogen. According to the contract, our supervisor required that a leak test be conducted after the hydrostatic test was successful. However, the other party stated that the setting pressure of the safety valve we provided was lower than the design pressure, and since the pressure used for the leak test is the design pressure, it was not possible to carry out the test in accordance with the regulations; therefore, no leak test was performed, and only 100% radiographic inspection was carried out. Our supervisor meant that when installing the safety valves, they should be set with a setting pressure higher than 17.13 MPa; after that, they go to the factory for a leak test, and once the test is complete, the safety valves are sent back to the factory to have their setting pressure adjusted to 15.7 MPa. I’m not sure if this will work My testing setup requires such a component, but I’m not from a related field and don’t know much about it. I’d appreciate some advice from everyone here; thank you.
The airtightness test is more dangerous than the hydrostatic test. What type of pressure vessel do you have? The testing equipment used must be quite small, right?
Since an airtightness test is required, the maximum allowable operating pressure should be specified (a value higher than the design pressure, such as 19 MPa). By setting the relief valve’s opening pressure at 18 MPa, an airtightness test can be conducted: lol
There is a claim that safety valves are not installed during airtightness tests, but I’m not sure what the basis for this is
During the airtightness test before the first use, it is carried out at the design pressure without activating the safety valve; subsequent airtightness tests only need to be conducted up to the operating pressure.
Code requirement 4.8.3(2): When conducting a leak test, the safety accessories should generally be installed in their entirety; subsequently, during the leak test, the operating pressure is applied. This standard does not mention anything regarding this
We all block the safety valves first before ensuring airtightness
For containers that are to undergo airtightness testing, some are equipped with safety valves; the container’s drawings must indicate the maximum allowable operating pressure, and the strength calculations must be based on this maximum allowable pressure
First of all, 100% radiographic testing cannot replace a gas tightness test. But your airtight pressure of 17 MPa is, in other words, just air pressure – who would dare to work on it for you?
1. Any requirement for airtightness specified on the drawings must be met; it’s not something to do just because your supervisor asks you to. As required by the drawings. 2. If the drawings specify airtightness requirements, your supervisor is doing the right thing. Sure.
Additionally, use proper nouns for labeling on the drawings; indicate on the drawings the set pressure of the safety valve – we do not use the term ‘opening pressure’.