The flexible pre-insulated CALPEX PUR-KING pipe system continues to perform reliably even after 25 years of service in a real district heating network. How well can a district heating pipe perform after a quarter of a century in operation? An independent investigation by KIWA Technology now provides robust findings.
A CALPEX PUR-KING pipe that had been in operation in a district heating network since 2000 was tested. For many years, the pipeline operated at an average service temperature of around 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 carried out 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 meaningful insight into the material properties of a pipe system that had already been in service in a real district heating network for around 25 years.
Expected to remain in service for more than another 25 years
In addition to the laboratory testing, KIWA also analysed the actual operating conditions of the pipeline over the previous 25 years.
Based on this data and the tests carried out, KIWA concludes that the investigated pipe system is expected to remain in service for more than another 25 years under the operating conditions analysed. The assessment applies to the tested pipe section and the specific operating conditions investigated. KIWA recommends further investigations for a complete assessment of an entire pipe network.
Practical experience backed by independent testing
For district heating network operators and planners, the long term performance of a pipe system is a key consideration. The current investigation shows how CALPEX PUR-KING performs after decades of use under real operating conditions.
In addition to its confirmed long term durability, CALPEX PUR-KING also offers very high insulation performance. The PUR insulation material used achieves a thermal conductivity of λ 0.0199 W/m*K, helping to minimise heat losses and support the energy efficient operation of local and district heating networks. Thanks to its high flexibility, the pipe system also enables long installation lengths and tight bending radii. This can reduce the number of joints and simplify installation work.
The results of the KIWA investigation therefore add a further independent performance verification to the many years of practical 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.
Find out more about CALPEX PUR-KING