scope:

NEN-EN 448 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: bend, tee, reducer, single use compensator and anchor. This European Standard applies only to factory made prefabricated fitting assemblies and single use compensators for continuous operation with hot water at various temperatures in accordance with EN 253. This European Standard applies to fitting assemblies with a minimum design pressure of 16 bar (overpressure) complying with EN 13941. This European Standard does not include calculation rules for loads and stresses. The design and installation rules, for the system, are given in EN 13941.