Can the valve pressure test be omitted?
Thread Content
Currently, some construction companies skip the pressure testing of valves and the individual calibration process. Although this saves time and labor, it creates potential problems during subsequent testing and operation; for example, the opening degree of the ball valve may not match the actual value, resulting in leaks when the valve is closed or flow restrictions when it is fully open； Stuck valves and leaks delayed the timing for repairs, affecting the commissioning progress. Pressure testing of valves is a common and essential testing method; it serves as an important means to verify the quality and safety of valves, to check their sealing performance and pressure resistance, and to ensure that they can function properly in use. For the pressure testing of valves, the construction contractor is required to clarify the following aspects: 1. Prepare a pressure testing plan: specify the workload, tools, personnel, schedule, standards, record forms, etc. 2. Testing pressure: The pressure should be increased gradually; sudden or rapid increases in pressure are not allowed. 3. Duration: Generally 2~3 minutes; important and special valves should be maintained for 5 minutes. 4. Conduct strength tests and sealing tests, and keep proper records. Other precautions: 1. Do not perform pressure testing: For special instruments and valves (oxygen valves, those with solid tungsten carbide components, valves with ceramic linings, ultra-high pressure valves, imported valves), upon arrival at the factory, check the quantity and ensure that the packaging is undamaged; it is possible to agree to skip the pressure testing in such cases. Before installation, the construction party must carry out the above checks for oil and grease removal on the oxygen valves, as well as inspect the internal ceramic components of special valves (such as tungsten carbide); if any issues are found, the valves shall not be installed. 2. After the valve testing station is set up, prior to conducting the tests, a report must be submitted to the supervisor or the client so that they can witness the valve tests; otherwise, no verification will be provided ； 3. The chloride ion content in the water used for the hydraulic pressure testing of stainless steel valves shall not exceed 100 mg/L ； 4. After the pressure test is successful, any water accumulated inside the valve should be removed immediately, and protective covers should be installed at both ends ； 5. A soft gasket is used for sealing between the valve clamping device and the valve sealing surface; when operating under high pressure, care should be taken in selecting the material of the gasket to prevent the clamping device from damaging the valve sealing surface. 2023.8.31
Valve pressure testing is a very important inspection method that cannot be omitted. Pressure testing can verify the quality and safety of valves, checking their sealing performance and pressure resistance, thereby ensuring that they function properly during use. The construction unit should clarify the contents and requirements of the pressure testing, and carry out the operations and keep records in accordance with relevant regulations. The contents of the pressure testing include preparing a pressure testing plan, specifying the workload, tools, personnel, schedule, standards, and record forms, etc ； The test pressure should be increased gradually; sudden and rapid increases in pressure are not allowed ； The duration is generally 2 to 3 minutes; for important and special valves, it should be 5 minutes ； Conduct strength tests and sealing tests, and keep proper records. In addition, there are other considerations: when special instruments and valves arrive at the factory, it is necessary to check the quantity and ensure that the packaging is not damaged; it is possible to agree to skip the pressure testing process ； The chloride ion content in the water used for the hydraulic pressure testing of stainless steel valves must not exceed 100 mg/L ； After the pressure test is successful, any water accumulated inside the valve should be removed immediately, and it should be protected with a cover ； Under high pressure, use soft gaskets between the valve clamping device and the valve sealing surface. Be sure to select an appropriate gasket material to prevent damage to the valve sealing surface. In summary, the pressure testing of valves is a necessary and indispensable step; it ensures the quality and safety of the valves, as well as enhances the reliability of testing and operation. .
The ideals are grand, but the reality is meager； The valve has already been tested for pressure upon leaving the factory; another test is conducted upon arrival. Who will provide the equipment and tools needed for these pressure tests (in various specifications), the pressure gauges, as well as determine the times for testing, inspection, and supervision?
So many construction companies refuse to do it, delaying until the installation phase is reached with no time left for pressure testing; they won’t carry it out even without a formal approval. In fact, in large projects, a number of problems are identified and resolved through pressure testing for leaks.
With 100 devices, it’s not certain that any are broken; the number of faulty devices is very small. So why not take the chance that none of them are broken? :lol
Conduct a random inspection. Pressure testing is required for some critical locations.
:I think the same about handshakes too – for important occasions: reactor feeding； Heat transfer oil and fuel gas feed valves, as well as interlock valves, require pressure testing by the construction party.
Choose manufacturers with high quality; products are inspected before leaving the factory. In principle, it’s not necessary as it is time-consuming and labor-intensive.