BS ISO 5208:2015 pdf download – Industrial valves — Pressure testing of metallic valves
3.1.2 When a purchaser specifies examinations or testing to be witnessed as described in 3.1.1, the valve manufacturer shall give notice to the purchaser at least five working days prior to the purchase order specified activity.
3.2 Witnessing If pressure testing in the presence of a representative of the purchaser is specified for valves that are in stock, painted or coated valves from stock may be retested without removal of painting or coating.
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.
4.4 Pressure measuring equipment
The equipment used for measuring test fluid pressure shall measure the fluid pressure with an accuracy of ± 5 % of the required test pressure.
4.5 Shell surfaces Before the shell test, valves shall not be externally painted or otherwise coated with materials capable of sealing against leakage from external surfaces of the shell. However, valves with internal liners, internal linings or internal coatings that form a design feature of the valve may be tested with the liner, lining or coating in place. In the event a purchaser specifies a retest of the shell test of valves that have been painted, retesting may be without removal of external paint or coatings.
4.6 Test fluid The test fluid to be used, as specified in the relevant tests detailed in this International Standard, shall be: — water, that may contain a corrosion inhibitor, kerosene or other appropriate liquid having a viscosity not greater than that of water, or — air or other suitable gas. The temperature of the test fluid shall be between 5 °C and 40 °C. Pressure testing valves with shell components of austenitic stainless steel, using water as the test fluid, requires that the chloride content of the water shall not exceed 100 × 10 −6 (100 ppm). NOTE A purchaser may specify, in a valve procurement purchase order, that a wetting agent be added to water used as a test fluid.
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.
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.
4.8.4 For the purpose of identifying required tests, test duration times and calculating closure leakage rates, it is necessary to establish the equivalent DN number for those valves that have size designations other than DN. The equivalent DN numbers of valves having flanged ends, threaded ends, weld ends, capillary or compression ends shall be as given in Table A.1.
4.8.5 A shell test option using gas as a test fluid may be specified in a valve procurement purchase order. In this event precautions are vital to safe conduct of this test, see 4.1.
4.9 Closure test compliance Valve types listed in Table 1, for which a high-pressure closure test is an option, are nevertheless required to be able to pass the test (as a test of the valve closure structure). Results of tests confirming the ability of the valve design to pass the high-pressure closure test shall be supplied when specified in a valve purchase order.