ISO 13341:2010 specifies the procedures to be followed when connecting cylinder valves to gas cylinders. It specifically applies to all valve and cylinder combinations connected with ISO screw threads as specified in ISO 10920 and ISO 11363-1. It defines routines for inspection and preparation prior to valving for both taper and parallel screw threads.Torque values are given for steel and aluminium gas cylinders including composite cylinders with steel or aluminium boss. The procedures and practices specified in ISO 13341:2010 can be beneficially applied to other valve to cylinder screw thread connection systems.