ÖNORM EN 448

This European Standard specifies requirements and test methods for fittings of prefabricated thermally insulated pipe-in-pipe assemblies comprising a steel service fitting from DN 20 to DN 1200, rigid polyurethane foam insulation and an outer casing of polyethylene for use in directly buried hot water networks with preinsulated pipe assemblies in accordance with EN 253. This European Standard covers the following fittings: bends, T-pieces, reducers, single use compensators and anchors. This European Standard applies only to insulated fitting assemblies and single use compensators for continuous operation with hot water at various temperatures in accordance with EN 253:2009, Clause 1. This European Standard applies to fitting assemblies with a minimum design pressure of 16 bar (overpressure) complying with EN 13941. Guidelines for quality inspection are given in Annex A of this European Standard. Procedures for PE-welding are given in Annex B of this European Standard.