What should be done if a pipe cannot be subjected to either a hydrostatic test or a pneumatic test?
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What should be done if a pipe cannot be subjected to either a hydrostatic test or a pneumatic test? Is this kind of situation possible? In our renovation projects, it is common to encounter situations where only a short section of pipe needs to be replaced, and it’s not possible to isolate the area before and after that section. As a result, the costs associated with conducting experiments are higher compared to when only one section of pipe needs to be replaced; neither the owners nor the construction teams want to undertake such work. And the site indeed does not have the conditions for testing; what should be done in such a situation? Please help me understand this, thank you!
Was the initial renovation not well planned? During normal modification, isolation valves are required in order to carry out the work. Otherwise, while the system is running, wouldn’t the media inside come out in just a few minutes? How can we still ensure the safety of the workers carrying out the renovation? Either the medium inside you is non-toxic and basically harmless. If that’s the case, just run the medium through it to check for any leaks; if there are leaks, simply seal them
Perform ultrasonic testing and radiographic testing on all welds of this pipeline simultaneously
Requirements regarding the exemption from pressure testing are specified in both GB20235 and GB/T20801; see the attachment
Thank you. Actually, I’m just looking for a design basis.
Can’t just replace one section of pipe without adding a flange?
In line with the requirements of GB/T 50235, page 50
SH3501-2011 also has requirements regarding the exemption from pressure testing, see Clause 8.1.21
It can be tested together with the previous pipelines
SH 3501-2011 Code for Construction and Acceptance of Steel Piping Systems for Toxic and Flammable Media in Petrochemical Industries 8.1.21 When the design unit or the project owner considers that hydraulic or pneumatic testing of the piping system to be impractical, the pressure test can be waived, provided that the following requirements are met: a) The circumferential, longitudinal, and spiral weld joints must pass 100% radiographic testing or 100% ultrasonic testing; b) The joints connecting to branch pipes and the fillet weld joints must pass 100% surface non-destructive testing; c) The piping system must have undergone flexible analysis as specified; d) The piping system must pass a sensitivity leak test.