UL 252-2017 pdf download – Compressed Gas Regulators.
8.3 An inlet connection shall not permit attachment of a station or line regulator to a storage cylinder. 8.4 Pipe threads shall comply with the Standard for Pipe Threads General Purpose, ANSI/ASME B1.20.1, or the Standard for Dryseal Pipe Threads, ANSI B1.20.3. Exception: Regulators intended for use in installations where pipe fittings incorporate other than NPT type threads shall be permitted to be provided with pipe threads complying with a national pipe thread standard compatible with those fittings. The pipe thread type shall be identified in accordance with 21.4. 8.5 Outlet hose connections for welding and cutting equipment, if used, shall be provided with right-hand threads for nonfuel gases and with left-hand threads for fuel gases, and comply with the Standard Connections for Regulator Outlets, Torches and Fitted Hose for Welding and Cutting Equipment, CGA Pamphlet E-1. 8.6 The outlet connection of a regulator for use with nitrogen, carbon-dioxide or inert gases, when provided, may be a slip-on hose connector of the serrated stem type or a quick-connect tube connection. 9 Accessories 9.1 Accessories provided with or installed in the regulated pressure ports of the regulator, such as pressure gauges, flowmeters, relief devices and shut-off valves, shall comply with the applicable requirements of the Standard for Compressed Gas Regulator Accessories, UL 252A. 9.2 Gauges reading over 1000 psig (6.89 MPa) shall conform with the requirements of the Standard for Gauges, Indicating Pressure, for Compressed Gas Service, UL 404. 9.3 Gauges with ranges of 1000 psig (6.89 MPa) or less, shall be subjected to the Excess-Pressure Test, Section 13. Gauges that comply with the Standard for Compressed Gas Regulator Accessories, UL 252A with a Class Rating equal to or greater than the Class Rating of the regulator, need not be subjected to the Excess-Pressure Test, Section 13.
10 General 1 0.1 Representative samples of a regulator are to be subjected to the tests described in these requirements. Additional samples of parts constructed of nonmetallic materials, such as diaphragms and valve seat discs, are required for immersion and aging tests. 10.2 The tests for seat- and external-leakage described in Section 12 are performance tests intended to evaluate the regulator design. They are not intended to specify the manner in which production-line tests for seat- and external-leakage are to be conducted.