What should be done with the valves on high-pressure welded pipelines during pressure testing?
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High-pressure thick-walled pipes are welded, and valves are also welded to match the same pressure as the pipes. Although valves are also subjected to pressure tests and airtightness tests upon leaving the factory, the testing time is much shorter than that for pipes. If the pipes and valves have been welded together, in this case a pressure of 1.5 times the design pressure is applied to the pipes. As for the various valves present on the pipes – manual valves, control valves, regulating valves, remotely controlled valves, etc. – should they be left fully open during pressure testing, or should the internal components of the valves be removed before testing? Alternatively, the design pressure for the welded valves should be selected based on 1.5 times the design pressure of the pipes. I would also appreciate the advice from all the experts! ! !
When conducting pressure tests on welded pipes, it is necessary to take appropriate action regarding the valves already installed on the pipes, in order to ensure the safety and reliability of the entire system. Here are some suggestions on how to handle the valves on pipelines during high-pressure welding pipeline testing: 1. Valve selection: When installing valves, it is necessary to ensure that their designed pressure is not lower than the test pressure of the pipeline system. In other words, if the piping system is designed to operate at higher pressures, and a pressure of 1.5 times the system’s operating pressure is applied during testing, then the valves must also be able to withstand this pressure without being damaged. 2. Valve handling: Before conducting pressure tests, different measures may be required for different types of valves. - Manual valves (such as globe valves, ball valves, etc.): Generally, these valves can be pressure-tested while in the fully open position. This ensures that the interior of the valve is not damaged as a result of the pressure test. - Control valve: Control valves are usually very delicate, and may need to be removed or bypassed with a blind flange before pressure testing to avoid damage. - Control valve: Control valves may contain complex internal components that are highly sensitive to pressure and flow rate. During stress testing, it may be necessary to remove its internal components, or to use methods recommended by the manufacturer to protect the control valve. - Remote-controlled on/off valves: These types of valves may contain electrical or other vulnerable components, and measures need to be taken in accordance with the manufacturer’s recommendations, including possible removal, full opening, or protection. 3. Prevent damage: During pressure testing, it is necessary to ensure that the valve does not suffer damage beyond its design specifications as a result of the test pressures. 4. Safety precautions: All safety precautions must be followed when conducting pressure tests, including but not limited to ensuring that the area is free of people, and taking measures to prevent damage or malfunction of equipment resulting from possible pressure leaks. The final treatment method should be determined with reference to the valve manufacturer’s recommendations, relevant industry standards and specifications, as well as the specific requirements of the project. In some cases, if the manufacturer permits it and safety standards are met, the valve may not require its internal components to be removed in order to undergo pressure testing. It is crucial to always ensure safety, and before carrying out such operations, be sure to consult experienced engineers or technicians. .