Pressure testing issues with stainless steel valves
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The pipeline valves of the installation have been in place for 3 years; work is now set to begin. Hydrostatic tests were conducted on these valves before they were installed. Is it necessary to remove the stainless steel valves and conduct pressure tests again now?
Depending on its importance, whether internal leakage affects the operation of the device – normally, all valves will experience internal leakage after being in use for a while
After internal leakage occurs and the valve needs to be replaced, is it necessary to repair the removed valve? Now, most of them are replaced; only a small portion can be repaired
If pressure is not maintained after the system is pressurized and cut off, it’s not too late to disassemble it
First, let me clarify a fact: we are a manufacturer that produces butterfly valves in stock. Before they are put into storage, they are subjected to pressure testing, and only after passing this test are they allowed to be stored. 1-2 months later, when the customer needs it again and the valve is taken out for pressure testing, there is still a 1-2% chance of leakage. Speaking of this, after such a long time, leakage will occur; I think that’s normal. . . . Then, it depends on the leakage requirement specified for this valve during design. . .
It is recommended to remove components from critical locations and re-apply pressure; where pressure retention tests can be conducted, such tests should be carried out, and there is no need to remove the components just to apply pressure.
Generally, pressure testing is carried out within the system, and if any issues are found, then it is disassembled for inspection. If high standards are required, it’s safer to remove everything and conduct a pressure test.
It is recommended to remove it and apply pressure; after such a long time, internal leakage is bound to occur. If it isn’t detected, things will get complicated once it starts operating.
Treatment should be carried out based on the characteristics of the equipment; for continuously operating closed systems where it is inconvenient to replace valves, it is recommended to perform pressure testing.