Hydraulic test
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I have encountered this issue in practice: both pressure vessels and pressure pipelines require hydrostatic testing, but according to the regulations, the test pressure for vessels should be 1.25 times the design pressure, while for pipelines it should be 1.5 times the design pressure. The container and the pipeline are connected together; pressure can only be applied to the container, and it’s not possible to apply pressure to the pipeline separately. So how is this hydrostatic test carried out?
Pressure vessels must undergo hydrostatic testing before leaving the factory; then why is it still necessary to do so after piping is installed on-site? I don’t understand; it’s sufficient to conduct a pressure test on the pipeline on site. Also, why is it not possible to apply pressure to the pipeline? No tee, no vent, no complete drainage? ! ! That’s not possible. :lol
Isolate the pipes and containers, apply pressure to verify that it is within acceptable limits, then connect them for a hydrostatic test at 1.25 times the normal pressure
By disconnecting the equipment from the pipes, it is possible to test the pipes individually; however, this approach can be problematic in some cases, as it is difficult to implement when the pipes are large in size or numerous in quantity. If the pipe itself is free of defects, it is also convenient and reliable to perform non-destructive testing on the weld area. I’m not sure if this helps you.
It is sufficient to perform pressure testing on each end of the pipeline and equipment using blind flanges; there is no need to conduct pressure testing on them together.
If the same pressure cannot be applied simultaneously, the equipment and pipes must be pressurized separately; or if there is a bypass, it should be used for pressure testing. Sometimes, for the same reason in design—namely to increase the design pressure of the equipment—if it isn’t taken into account in advance, they are separated.