ASME B16.40-2008 pdf – Manually Operated Thermoplastic Gas Shutoffs and Valves in Gas Distribution Systems
ASME B16.40-2008 pdf – Manually Operated Thermoplastic Gas Shutoffs and Valves in Gas Distribution Systems.
The workmanship used in the manufacture and assembly of each valve shall provide gas tightness, safety and reliability of performance, and freedom from injurious imperfections and defects.
(bJ Design details not addressed in this Standard are the n’spunsihilily of the manufacturer
2.2.1 Valve Shell The pressure-containing valve shell shall be n.ide from either polyethylene (RE) or polyamide 11 (PA-I 1) materials specified in and quail. fied to the requirements for pipe and fittings as listed in ASTM D 2513.
2.2.2 Parts Other Than the Valve Shell. Parts other than the valve shell, which contribute to pressure containment or retaining differential pressure across the closure element, shall be resistant to the gass in para. 1.1(c). Such parts shall be designed to withstand normal valve-operating loads and, in addition, shall provide long-term pressure-containment integrity consistent with the valve shell. The sustained pressure tests of para. 6.3.3 shall qualify the design and material selected for these parts. which Include, hut are not limited to, the closure member, stems or shafts (if they are designed to retain pressure), and fasteners retaining shell sections.
± 5°F (—29°C ± 3°C) and 140°F ± 5°F (60°C ±3°C) without visible leakage to atmosphere and without affecting the internal seat-sealing performance of the valve. The method of test is as follows. A closed valve shall be cooled to a temperature of -20°F ± 5°F (-29°C ± 3°C) and held there for an 18-hr minimum. The valve shall then be pressurized with air or gas to a differential pressure across the seat equal to the valve design pressure.
The valve shall then 1w opened against the applied- differential pressure, using a torque less than or equal to that of Table 2 at the -20°F (-29°C) values and then closed (no differential pressure across the seat required). The valve shall then Lw tested to meet the requirements of para. 6.2 while at —20°F (—29°C), except nonfreezing leak-detection agents shall be used. The valve shall then be heated to a temperature of 140°F ± 5°F (60°C ± 3°C) and held there For an 18-hr minimum. The dosed valve shall then be pressurized with air or other gas to a differential pressure across the seat equal to the valve’s design pressure at 140°F (60°C). The valve shall then be opened against the applied-differential pressure using a torque less than or equal to that of Table 2 1140°F (60°C)J values and then closed (no differential pressure across the seat required). The valve shall then be tested to and meet the requirements of para. 6.2. while at 1441°F (60°C).
6.3.3 SustaIned-Pressure Test. Each basic valve design shall be suhcted to the sustained-pressure tests described herein to evaluate the long-term pressure integrity of the valve shell and closure elements. All valves shall be in the open position for the PressureBoundary Test Isee para. &3.3(a)I and in the closed position for the Closure ‘erification Test (see para. 6.3.3(b)J,
For both PE and PA-Il. Table 3 offers two choices of pressures and duration times for the sustained pressure test, The valve manufacturer may choose to test for 1.(XXJ hr at the lower listed pn’s.surws. depending on valve DR. or for 170 hr at the higher listed pressUres. Either choice is valid. The valve manufacturer is not required to perform both tests.
The valves shall not fail, as defined in ASTM D 1598, when subjected to the sustained pressure test.
(a) Prrs.ure-Bouedary Tests. Six samples of each basic valve design shall be connected at both ends to thermoplastic pipe of appropriate wall thickness of a length of at least five times its outside diamc-teror 20 in. (510mm), whichever is less. These assemblies shall be subjected to a sustained-pressure test test as chosen from the sustained test pressures and minimum durations as listed In Table 3. The DR’ for the valve shall be used In determining the test pressure. Failure of two of the six samples tested shall constitute Failure in the test. Failure of one of the six samples tested is cause for a retest of six additional samples. Failure of one of the six samples in retest shall constitute failure in the test.