The flexible, pre-insulated CALPEX PUR-KING piping system continues to deliver strong performance even after 25 years of service in a real-world district heating network. How well does a district heating pipe perform after a quarter century in operation? An independent investigation by KIWA Technology now provides reliable findings.
A CALPEX PUR-KING pipe that had been in service in a district heating network since 2000 was tested. For many years, the pipeline operated at an average temperature of approximately 75 °C, with temperatures occasionally reaching up to 85 °C.
The investigation was initiated by our long-standing partner Weijers Waalwijk and commissioned from KIWA. For this purpose, a section of pipe was removed from the existing network and examined in the laboratory.
More than 1,000 hours with no signs of failure
The investigation focused on the remaining service life of the PEX carrier pipe. Among other tests, KIWA conducted a hydrostatic pressure test in accordance with ISO 1167-2. The pipe was tested at 95 °C and a stress of 4.6 MPa. Under these conditions, the standard specifies a minimum test duration of 165 hours for new PEX pipes.
The tested pipe section showed no signs of failure even after more than 1,000 hours. The investigation therefore provides valuable insight into the material properties of a piping system that had already been in service in a real-world district heating network for approximately 25 years.
Expected to remain in service for more than another 25 years
In addition to the laboratory testing, KIWA also analyzed the pipeline's actual operating conditions over the previous 25 years.
Based on this data and the tests performed, KIWA concluded that the tested piping system is expected to remain in service for more than another 25 years under the operating conditions analyzed. The assessment applies to the tested pipe section and the specific operating conditions analyzed. KIWA recommends further testing for a comprehensive assessment of an entire piping network.
Real-world experience backed by independent testing
For district heating network operators and engineers, the long-term performance of a piping system is a key consideration. The current investigation demonstrates how CALPEX PUR-KING performs after decades of service under real-world operating conditions.
In addition to its confirmed long-term durability, CALPEX PUR-KING also provides excellent thermal insulation performance. The PUR insulation material used achieves a thermal conductivity of λ 0.0199 W/m*K, helping to reduce heat loss and support the energy-efficient operation of local and district heating networks. Thanks to its high flexibility, the piping system also allows for long installation lengths and tight bending radii. This can reduce the number of connections and simplify installation.
The results of the KIWA investigation add another independent verification of system performance to the many years of real-world experience with CALPEX PUR-KING. View the test report "Rapport KIWA Technology Restlevensduur CALPEX"
We would like to thank Weijers Waalwijk for initiating and commissioning this independent investigation and for our long-standing partnership.
Learn more about CALPEX PUR-KING