UL 536-2021 pdf download – Flexible Metallic Hose.
1.9 This standard does not cover the following: a) Gas appliance hose connectors for handling fuel gases at 5 psig (34.5 kPa) or less, which is covered by Connectors for Gas Appliances, CSA 6.10/ANSI Z21.24; b) Portable outdoor cooking appliance fuel hose, which is covered by Gas Hose Connectors for Portable Outdoor Gas-Fired Appliances, CSA 8.4/ANSI Z21.54; c) LP-Gas and natural gas delivery hose or fuel supply systems, which is covered by the Standard for Pigtails and Flexible Hose Connectors for LP-Gas, UL 569 and the Standard for LP-Gas Hose, UL 21 or the Standard for Elastomeric composite hose and hose couplings for conducting propane and natural gas, CSA 8.1, and the Standard for Thermoplastic hose and hose couplings for conducting propane and natural gas, CSA 8.3; d) Underground piping products for liquid fuels, which is covered by the Outline of Investigation for Metallic Underground Fuel Pipe, UL 971A, or the Standard for Metallic and Nonmetallic Underground Piping for Flammable and Combustible Liquids, CAN/ULC-S679; e) Flexible connector piping for liquid fuels, which is covered by the Standard for Flexible Connector Piping for Fuels, UL 2039, or the Standard for Flexible Connector Piping for Fuels, CAN/ULC-S633; f) Motor fuel dispensing hose, which is covered by the Standard for Hose and Hose Assemblies for Dispensing Flammable and Combustible Liquids, ANSI/CAN/UL 330.
5.6 Cadmium plating shall not be less than 0.0003 in (0.008 mm) thick, and zinc plating shall not be less than 0.0005 in (0.013 mm) thick, except on parts where threads constitute the major portion of the area, in which case the cadmium or zinc plating shall not be less than 0.00015 in (0.0038 mm) thick. 5.7 A gas containing part shall be made of material having a melting point (solidus temperature) higher than 1000 °F (538 °C) and a tensile strength not less than 10,000 psig (69 MPa) at 400 °F (204 °C). 6 Assembly 6.1 One end of each length of flexible metallic hose shall terminate in a permanently attached pipe flange, separable coupling, or union to facilitate connection without twisting the hose. The other end of each length shall be similarly equipped or shall terminate in a screwed or flanged fitting. 6.2 Pipe threads shall be in accordance with the Standard for Pipe Threads, General Purpose (Inch), ANSI/ASME B1.20.1. Exception: Flexible metal hose which incorporate otherthan NPTtype threads shall be permitted provided the pipe threads complywith a national pipe thread standard and the thread type is marked on the hose. 6.3 Flexible metallic hose connections that are flanges shall comply with a National/Bi-National Standard for pipe flanges and flanged fittings. PERFORMANCE 7 General 7.1 Flexible metallic hose shall be tested on the following basis consistent with the intended use of the product: a) Size or diameter. b) Minimum length. c) Minimum radius of bend.