DS EN 448:2009 District Heating Pipes - Preinsulated Bonded Pipe Systems For Directly Buried Hot Water Networks - Fitting Assemblies Of Steel Service Pipes, Polyurethane Thermal Insulation And Outer Casing Of Polyethylene Provides 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 insul