EN 253:2009+A2:2015

European foreword
Foreword
Introduction
1 Scope
2 Normative references
3 Terms and definitions
4 Requirements
5 Test methods
6 Marking
Annex A (informative) - Relation between actual
        continuous operating conditions and
        accelerated ageing test conditions
Annex B (informative) - Calculation of the minimum
        expected thermal life with operation at
        various temperatures with respect to PUR
        foam performance
Annex C (normative) - Calculated Continuous Operating
        Temperature (CCOT)
Annex D (informative) - Guidelines for inspection
        and testing
Annex E (informative) - Radial creep behaviour of the
        polyurethane foam (PUR)
Annex F (normative) - Thermal conductivity of
        pre-insulated pipes - Test procedure
Annex G (informative) - National A-deviations
Annex H (informative) - Main changes from the previous
        edition of EN 253
Annex I (informative) - Waste treatment and recycling
Bibliography

This European Standard specifies requirements and test methods for straight lengths of prefabricated thermally insulated pipe-in-pipe assemblies for directly buried hot water networks, comprising a steel service pipe from DN 15 to DN 1200, rigid polyurethane foam insulation and an outer casing of polyethylene. The pipe assembly may also include the following additional elements: measuring wires, spacers and diffusion barriers.This standard applies only to insulated pipe assemblies, for continuous operation with hot water at various temperatures up to 120 °C and occasionally with a peak temperature up to 140 °C.The estimation of expected thermal life with continuous operation at various temperatures is outlined in Annex B.