UL 109 Ed. 7-2025

Tube Fittings for Flammable and Combustible Fluids, and Marine Use - Published Date: December 11, 2025

1.1 These requirements cover fittings to be used in tubing carrying:  a) Fuel gases such as acetylene, liquefied petroleum gas (LP-gas), manufactured and natural fuel gases, and other liquefied and non-liquefied flammable gases that are stable because of their composition or because of the conditions of storage,  b) Gasoline or gasohol formulated in accordance with Standard Specification for Automotive Spark-Ignition Engine Fuel, ASTM D4814,  c) Diesel fuel formulated in accordance with Standard Specification for Diesel Fuel Oils, ASTM D975,  d) Heating fuel oils formulated in accordance with Standard Specification for Fuel Oils, ASTM D396, and  e) Kerosene formulated in accordance with Specification for Kerosine, ASTM D3699.  1.2 The requirements for "Marine Use" cover fittings to be used with tubing carrying gasoline or gasohol formulated in accordance with Standard Specification for Automotive Spark-Ignition Engine Fuel, ASTM D4814, or diesel fuel formulated in accordance with Standard Specification for Diesel Fuel Oils, ASTM D975.  1.3 This standard does not cover tube fittings for liquid or gaseous Biofuels or Ethanol fuels other than gasohol noted in 1(b) and 2.  1.4 Requirements for the selection, installation, and use of the fittings covered by this Standard are included in the Standards of the National Fire Protection Association pertaining to storage and use of flammable and combustible fluids, such as:  NFPA 30, Flammable and Combustible Liquids Code  NFPA 31, Installation of Oil-Burning Equipment  NFPA 32, Dry Cleaning Plants  NFPA 51, Design and Installation of Oxygen-Fuel Gas Systems for Welding, Cutting, and Allied Processes  NFPA 54, National Fuel Gas Code  NFPA 58, Storage and Handling of Liquefied Petroleum Gases  1.5 Requirements for the selection, installation, and use of fittings for "Marine Use" as covered by this Standard are included in the Standard for Pleasure and Commercial Motor Craft, NFPA 302, and the appropriate publications of the American Boat and Yacht Council.  1.6 This standard does not cover fittings for refrigerant service. All fittings, intended for service on refrigerant systems shall comply with the requirements of UL 207, Standard for Refrigerant-Containing Components and Accessories, Nonelectrical.