DIN EN 253:2015-12

This European Standard specifies requirements and test methods for straight lengths of factory made thermally insulated pipe-in- pipe systems for directly buried hot water networks consisting of a steel service pipe from DN 15 to DN 1200 with rigid polyurethane foam thermal insulation and a casing of polyethylene. The pipe assembly may also include the following additional elements: measuring wires, spacers and diffusion barriers. This standard applies only to thermally insulated composite pipe systems for continuous operation with hot water at different operating temperatures of up to 120 °C and occasionally occurring peak temperatures of up to 140 °C. The estimation of the expected thermal lifetime for continuous operation at different operating temperatures is explained in Annex B.