This International Standard 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 in Annex A for steel and aluminium gas cylinders including composite cylinders with steel or aluminium boss.NOTE The procedures and practices specified in this International Standard can be beneficially applied to other valve to cylinder screw thread connection systems. ISO/TR 11364[4] lists the valve to gas cylinder threads in use worldwide. It gives details of the thread identification codes, whether the threads are interchangeable with ISO threads and if the taping procedure and torque values specified in this International Standard can be used. ISO/TR 11364[4] gives clear guidance for the method and torque for all listed inlet threads, which are not interchangeable.