Questions regarding the requirement for low-pressure sealing tests in the \"Specifications for Inspection and Management of Petrochemical Valves\" (SH 3518-2013)

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During a major quality inspection at the headquarters of a petrochemical project, issues were identified in the valve testing procedures as part of the pipeline-related inspections: \"All records of the gate valve testing show that high-pressure sealing tests were conducted, which does not comply with requirement 5.3.3 of SH3518-2013, which stipulates that low-pressure sealing tests must be carried out for gate valves.\" ” After reviewing the relevant standards, I believe that at construction sites, valve testing requires only a shell pressure test, an upper seal test, and a high-pressure seal test, in the absence of any special design requirements. The reasons are as follows: 1. The \"Code for Inspection and Management of Petrochemical Valves\" (SH 3518-2013) states in its explanatory notes regarding the low-pressure seal test: \"5.3.2 The pressure requirements for the low-pressure seal test shall comply with the corresponding provisions of JB/T 9092 \"Inspection and Testing of Valves\".\" JB/T 9092-1999 \"Inspection and Testing of Valves\" specifies the requirements for valve manufacturers to inspect and test valves prior to their release from the factory, rather than covering tests to be carried out at the construction site before the valves are installed. 2. Regarding valve testing in the \"Code for Construction of Industrial Metal Piping Projects\" (GB50235-2010): \"4.2.3 The shell pressure test and sealing test of valves shall be carried out using clean water as the testing medium,...\" Since the testing medium is clean water, the sealing test mentioned here refers to a high-pressure sealing test, rather than a low-pressure sealing test, as the medium used for low-pressure sealing tests is gas at 0.6 MPa. 3. Regarding valve testing in the \"Code for Acceptance of Construction Quality of Industrial Metal Piping Projects\" (GB 50184-2011): \"4.0.3 Valves shall undergo shell pressure tests and sealing tests; valves with an upper sealing structure shall also undergo an upper sealing test, and they shall comply with the following requirements: 1) Valve testing shall be carried out using clean water as the testing medium.\" When testing stainless steel valves, the chloride ion content in water must not exceed 25×10‑6 (25 ppm). Once the test is passed, the water stains should be removed immediately. When there are special requirements, the test medium shall comply with the provisions of the design documents. 2) The shell test pressure of the valve shall be 1.5 times the maximum allowable operating pressure of the valve at 20°C ； The sealing test pressure shall be 1.1 times the maximum allowable operating pressure of the valve at 20°C ； When the valve nameplate indicates that a high-pressure sealing test is not suitable for the maximum operating pressure difference or the actuator supplied with the valve, the test pressure shall be 1.1 times the maximum operating pressure difference indicated on the valve nameplate ； The upper sealing test pressure for the valve should be 1.1 times the valve’s maximum allowable operating pressure at 20°C ； The test pressure for the jacket portion of a jacketed valve should be 1.5 times the design pressure. 3) The duration under test pressure shall not be less than 5 min. ...”It is also specified here that the test medium is clean water, not gas; therefore, the sealing test mentioned here refers to a high-pressure sealing test, rather than a low-pressure one. 4. Regarding valve testing in the \"Specifications for Inspection and Installation of Valves\" (SY/T 4102-2013): \"4.1.2 Before installation, each valve shall undergo a shell pressure test and a sealing test.\" Valves with an upper sealing structure shall undergo an upper sealing test ； “The low-pressure sealing test shall be carried out in accordance with the design requirements,” which makes it clear that such a test is not performed if the design does not require it. 5. The sealing tests in the valve testing standard tables for SH/T 3503 and SH/T 3543 also refer to high-pressure sealing tests. In summary, valve testing at the construction site should not include low-pressure sealing tests, unless required by the design. Furthermore, regarding the \"Specifications for Inspection and Management of Petrochemical Valves\" (SH 3518-2013), I believe it is primarily formulated based on API 598, JB/T 9092, and GB/T 13927. All of these standards set requirements for valve manufacturers to conduct inspections and tests on valves prior to their release; they are not suitable for valve testing at construction sites. For example, the pressure holding time for valves at the site is always 5 minutes, regardless of their type or size, whereas SH 3518 allows for varying pressure holding times. Therefore, it is hoped that when SH 3518 is revised in the future, it will focus solely on the inspection, testing, and management of valves at construction sites, without imposing the inspection and testing requirements applied before valves leave the factory. I believe that the \"Code for Inspection and Installation of Valves\" (SY/T 4102-2013) is more suitable for use at our construction sites. I wonder if my understanding and doubts are valid?