ISO 5208:2008 pdf download – Industrial valves — Pressure testing of metallic valves.
3.3 Closure pressure testing options A purchaser may specify, in a valve procurement purchase order, optional closure testing. See Table 1. 4 Requirements for pressure testing 4.1 Forewarning A user of this International Standard needs to properly take into account the hazard involved with working with pressurized gases and liquids. 4.2 Location Pressure tests shall take place either at the site of the valve manufacture or at a test facility under the supervision of the valve manufacturer. 4.3 Test equipment 4.3.1 The test equipment shall be of such a design, that it does not subject the valve to externally applied loads that may affect the results of the test. When end-clamping devices are used, the valve manufacturer shall be able to demonstrate that, during the valve closure test, they do not serve to reduce the resultant leakage. Valves designed for installation between flanges, e.g. wafer style check or butterfly valves, shall not have test equipment clamping forces applied that are so great as to bear upon the pressure test results. 4.3.2 When equipment such as volume loss detection devices are used, the manufacturer shall be capable of demonstrating equivalence of the system with the requirements of this International Standard.
4.7 Test pressure Except for low-pressure closure testing, test pressures are related to the valve CWP which in turn is related to the shell material of the valve under test. NOTE Piping systems in which valves are installed are subjected to pre-operational pressure testing. Therefore, valve standards, by and large, include requirements for CWP-related marking to be on an attached valve identification label or valve body. 4.8 Pressure tests 4.8.1 Compliance with this International Standard for pressure testing requires: ⎯ satisfactory execution of the required tests listed in Table 1, taking into account the exceptions and clarifications of 4.8.3; ⎯ satisfactory execution of the tests that may be required by the referencing valve product standard, which are listed as optional in Table 1; ⎯ pressure testing is conducted following written procedures prepared by the valve manufacture, which are in accordance with this International Standard. 4.8.2 In the event that a purchaser specifies optional tests as shown in Table 1, the optional tests shall be performed in addition to Table 1 required tests. 4.8.3 The following clarifications and exceptions to Table 1 are applicable: ⎯ for plug valves that rely on a sealing compound to effect a closure seal, a high-pressure closure test is required and the low-pressure test is an option; ⎯ for valves having bellows stem sealing, a backseat test is not required; ⎯ for valves specified as double block and bleed, a high-pressure closure test is required and the low- pressure test is an option.