This Technical Report gives guidance and other provisions for the training, assessment and approval of fusion operators, with the aim of establishing and maintaining their competency in the construction of polyethylene (PE) piping systems for the supply of gaseous fuels in accordance with ISO 10839, for the supply of water, or in the construction of such systems used in other pressure applications. It covers the butt fusion, electrofusion and socket fusion jointing techniques and considers both the theoretical and practical knowledge necessary for making high-quality fusion joints.