When testing high-pressure pipelines, can instruments and valves be tested together?
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During the pressure testing of high-pressure pipelines in high-pressure gas filling installations, can the instruments, valves, flow meters, etc. installed on the pipelines be tested together as well? The pressure used for testing is 1.5 times the design pressure of the pipeline; please explain the reason.
For such situations, please refer to SH 3501-2011 Code for Construction and Acceptance of Steel Piping Projects for Toxic and Flammable Media in the Petrochemical Industry
The purging system needs to be removed, but the pressure testing must be carried out together with the process piping, with all valves fully open.
GB 50093-2013
For the initial pressure test, it is not recommended to fully open the instrument valves.
That’s a great question. I think it’s fine to conduct pressure testing together, as long as it’s ensured that impurities don’t get into the parts of the instrument sensors – such as the pressure tap pipes in orifice flow meters, or the vortex generators used in vortex flow meters
Pipes that have not been modified are acceptable; those that have been modified must first be purged and pressure-tested, and cannot be pressure-tested simultaneously with the gauge
Pressure testing is possible, but it is necessary to check whether the pressure rating of the instruments meets 1.5 times the design pressure of the pipeline
Sure, you can conduct a pressure test after the purging is complete, as long as the instruments don’t exceed their limits.
Yes, when selecting instruments, the pressure rating is usually one level higher than the design pressure of the pipes; even if the pressure rating is the same as that of the pipes, a pressure test at 1.5 times that pressure is allowed.
In fact, it’s not just a 1.5 times factor; when the operating temperature is very high, an additional coefficient is applied. Please refer to section 10.3 of GB50517