ASME B16.40:2002 pdf free download

ASME B16.40:2002 pdf free download.MANUALLYOPERATED THERMOPLASTIC GAS SHUTOFFS AND VALVES IN GAS DISTRIBUTION SYSTEMS.
3.2.2 Seat Test. Each valve shall be seal closure tested at 4 ± 2 psi (0.28 ± 0.14 bar) and at a minimum of 1.5 times the design pressure. These pressures shall be applied successively on each side of the valve seat(s) to check the valve-scaling performance in both directions. The full lest differential pressure shall he applied across the downstream scat if there is more than one scat. The test fluid shall be air or other gas and there shall be no visible leakage (no breaking away or buildup of bubbles) at the downstream scat as measured by the water over air or a leak detection solution method. If immersion is used, the depth from the water surface shall be no more than 12 in. (300 mm). Other means of leak detection may be used. provided they can be shown to be equivalent in leak- detection sensitivity. The scat test shall be conducted at a temperature of 73 ± 15°F (23 ± 8°C). The scat test’s fixtunng shall not restrain the valve against any mode of failure or leakage. The minimum duration of each portion of the test shall be as shown in Table 2.
3.3 Qualification Testing
3.3.1 Operational Test. It shall be denionsirated that each nominal size of each valve design is capable of successfully passing the scat leakage tests of pant. 3.2.2. after having completed ten fully opened/fully closed cycles at 73 ± 15°F (23 ± 8°C). The valve shall be pressurized with air or other gas to the design pressure at one port with the other port open to atmosphere before opening on each cycle. At the start of each cycle, the operating torque shall be measured and shall not exceed those in Table 3 for —20°F (—29°C).
3.3.2 Temperature Resistance. It shall be demonstrated that each nominal size of valve of each valve design is capable of being operated at temperatures of
—20 ± 5°F —29 ± 3:C) kind 100 ± SF (3g ± 3°C) without visible leakage to atmosphere and without affecting the internal seal-sealing perfonnance of the valve. The method of test is as follows. A closed valve shall be cooled to a temperature of —20 ± 5°F (—29 ± 3°C) and held there for 18 hr minimum. The valve shall then be pressurized with air or gas to a differential pressure across the seat equal to the design pressure.