This European Standard specifies requirements for joints, made under field conditions, between adjacent preinsulated pipes and/or fittings in district heating networks. The specified general requirements are also valid for field made T-branches, bends, reducers, caps, etc. The standard covers jointing of steel service pipes by means of fusion welding, the connecting of casing ends with joint casings and the thermal insulation with poured rigid PUR foam or prefabricated PUR-foam insulation. This standard specifies methods for type tests of complete joints and PUR-foam for joints under laboratory conditions. The requirements of this standard can also be applied to casing pipe weldings/connections of on site made fittings. The requirements of this standard are aiming at obtaining a technical life of the joints of at least 30 years.