Regarding the leakage rate during pressure testing of pipeline systems
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Hello, everyone! For system pressure testing, there are requirements regarding the pressure increase rate in vacuum conditions; however, no specifications for pressure retention tests under positive pressure have been found. I saw someone on Haichuan mention figures of 2% and 1.5% – I’m not sure where these values come from. If anyone knows, please provide some guidance. Thank you!
It’s available in the positive-pressure version of TSG D0001, but it’s quite different from what you showed in your screenshot: the pressure is increased to 1.5 times the design pressure, and then held at that level for 10 minutes； Then it is reduced to the design pressure, and the pressure is held for 30 minutes; the acceptance criterion is that the pressure does not drop. The claim in your screenshot that it can maintain stability for 6 hours is completely nonsense. . .
What you mentioned are the general strength test requirements; what I’m referring to are media that require integrity tests – it’s not sufficient to just apply water pressure or carry out foam testing.
Oh, generally, after pressure testing of industrial pipelines, leak testing is carried out next; this is specified in GB50235 and GB20801. This tightness test seems to be used for gas pipelines; it is specified in the \"Code for Construction and Acceptance of Urban Gas Transmission and Distribution Projects\" CJJ33—2005.
A pipeline had just been installed, and the project subjected it to a 2Bar nitrogen pressure test; there was no change over 4 hours (the sensor reading remained at 0.20MPa). After the insulation material was in place, it was observed that a small amount of liquid was seeping out from one weld point per hour – the amount was very small. Upon removing the insulation, a slight leak was indeed detected; this liquid emitted smoke when exposed to air, which is why it was noticed during the inspection. May I ask, is this testing method correct? I discussed it with the project team but got no conclusion.
I won’t calculate it based on the pressure changes caused by temperature.
The reaction tank has a volume of 3.6 cubic meters, and the temperature remains unchanged
Aren’t 2% and 1.5% already included in that screenshot of yours?
For hydrogen, oxygen also has similar stringent testing requirements.
I found this online; it isn’t from any standard, so I’m wondering if there are other explanations.