Questions regarding the hydrostatic test pressure
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Section 9.1.3 \"Hydraulic testing\" in the latest GB/T20801.5-2020 states that: d) If the test pressure specified above would result in circumferential or longitudinal stresses at the test temperature exceeding the material’s yield strength, or if the test pressure at that temperature is greater than 1.5 times the rated value of the component, then the test pressure may be reduced to the maximum value that does not cause the stresses to exceed the material’s yield strength or 1.5 times the component’s rated value at the test temperature. How do you choose the test pressure? Do circumferential stress, longitudinal stress, and 1.5 times the component’s rated value all need to be checked? Components include valves, seals, etc. Where can one find the rated values for these components?
Asking such questions doesn’t seem like something a designer would do. If it’s for direct use by a user, that’s fine; usually it’s just seal leaks, and checking those should resolve the issue. For reference only. Oh, as for the references for various parameters, each pipe fitting and equipment comes with relevant user manuals.
This issue should be addressed in relation to pressure vessels, and related attachments should not be included, although such attachments must meet the requirements for testing before they can be subjected to testing. The test pressure should be only slightly higher than the operating pressure, or it can be between the operating pressure and the design pressure; remember not to exceed the design pressure.
The calculation of axial stress and longitudinal stress refers to equations 3.3.3-1 and 3.3.4 in DL/T 5054-2016
The calculation of circumferential stress can refer to the provisions in clause 11.5.3.
The calculation of circumferential stress can refer to the provisions in clause 11.5.3.
May I ask which standard’s 11.5.3 is it?
Thank you, found it in 50316