Laboratory Test Results of a Pre-insulated Pipe with the EVOprotect® Diffusion Barrier After Nine Years of Service
Laboratory testing of a pre-insulated pipe section with the EVOprotect® diffusion barrier, operated for nine years in a district heating network, confirmed the retention of very good thermal conductivity parameters of the PUR foam and mechanical properties. The result of λ₅₀ = 0.0255 W/mK proved to be more than 12% better than the limit value required by EN 253 for new pre-insulated pipes.
In the assessment of pre-insulated pipe quality, increasing importance is attached not only to the initial parameters declared by manufacturers, but also to how the product performs after years of actual service. This is precisely why tests carried out on samples taken from an operating district heating network are of particular value.
The Radpol Pipes research report presents the results of laboratory tests conducted on a DN65/140 pre-insulated pipe section with the EVOprotect® diffusion barrier, in continuous operation since 2016 in the Kielce district heating network. The tests were performed by the accredited laboratory of Veolia Energia Warszawa in accordance with the requirements of EN 253. The results were documented in Test Report No. VWAW/DE/EB/EBB/WEW/25/PR01/1, dated 2 October 2025.
The key result concerns the thermal conductivity coefficient of the PUR insulation. After nine years of service, the following value was obtained:
λ₅₀ = 0.0255 W/mK
This result is more than 12% lower than the limit value of 0.0290 W/mK specified in EN 253 for new pre-insulated pipes. This means that the PUR insulation retained very good thermal properties despite long-term operation under actual service conditions.
The test results also confirm the high axial shear strength of the tested sample, amounting to 0.30 MPa. Foam density, compressive strength and cellular structure met the standard requirements, and the tested sample retained system integrity without any loss of adhesion between the foam and the steel service pipe and HDPE casing.
Test Results After Natural Ageing
The table below presents the test results for the Radpol Pipes pre-insulated pipe section with the EVOprotect® diffusion barrier after nine years of service (after natural ageing).
For comparison, the results are set against the requirements of EN 253.
Conclusions
The conclusions of the study are important from the perspective of network operators, designers and investors. They show that the quality of a pre-insulated system should be assessed not only on the basis of manufacturers’ declarations for a new product, but also on the basis of data confirmed after years of service. In practice, it is the long-term stability of thermal parameters that determines heat losses, energy efficiency and future operating costs of the district heating network.
We invite you to download the full laboratory test report: click here.
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