4.1 General
4.1.1 Each basic valve design shall be qualified and demonstrated as suitable for the service by testing randomly selected production valves of each size, type and pressure shell material according to the design qualification tests.
4.1.2 All tests, unless otherwise specified, shall be conducted at a temperature of 74°F ± 15°F (23°C ± 8°C).
4.1.3 Before each test is conducted, the valve shall he in the condition in which it would be placed in service.
4.2 Gas Tightness
4.2.1 The valve shall provide a shut-off when in the closed position and shall not leak to the atmosphere in the open or closed position when subjected progressively to internal air pressure of first 4 ± 2 psi (0.3 + 0.1 bar) and then to at least 1.5 times the pressure rating of the valve.
4.2.2 Method of Test for Gas Tightness. With the valve in the open position and the outlet plugged, the test pressure shall be applied to the inlet of the valve. The valve shall be immersed in a bath containing water at a temperature of 74°F ± 15°F (23°C ± 8°C) for a period of 15 seconds. Leakage, as evidenced by flow (breaking away) of hubbies shall not be permitted. The valve shall then be turned to the closed position, outlet opened and the test repeated.
4.2.3 Other means of leak detection may be used provided they can be shown to be equivalent in leak detection sensitivity.
4.3 Temperature Resistance
4.3.1 A valve should be operable at temperatures ranging from —20°F to 150°F (—29°C to 66°C) without affecting the capability of the valve to control the flow of gas.
4.3.2 The valve shall be maintained at a temperature of —20°F (—29°C) for a period long enough to allow all parts to COfl1C to equilibrium temperature. With the valve subjected to an internal air pressure at least equal to the pressure rating and with the outlet end of the valve arranged to vent to atmosphere, it shall be determined that it can be opened and closed.
4.4.5 Tensile Strength. A valve in both the open and closed positions shall withstand the tensile load specified in Table 4, when applied gradually to valve ends, without rupture or permanent deformation that would, after release of the tensile load, render the valve inoperable, incapable of providing a shut-off, or cause it to leak to atmosphere when tested as outlined in para. 4.2. Schedule 80 steel pipe shall be connected to the valve for the purpose of transmitting the tensile load.
4.4.6 Turning Torque. The torque required to continue to operate the valve after breaking loose from its set or stationary position shall not exceed the amounts specified in Table 5. All valves at the end of this test shall be capable of complying with the provisions of para. 4.2.
4.5 Flow Capacity
The valves, when in the full open position, shall meet the minimum gas flow as specified in Table 6. A valve of each size and type shall be tested to verify that the pressure loss is not greater than that specified in Table 6. The test shall he conducted using a technically recognized procedure such as that contained in ISA S75.02. The test fluid and type of test facility.