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Steel pipe

Pre-insulated steel pipe is a solid and efficient solution for district heating and cooling as well as industrial applications that require high temperature and pressure resistant pipes.

isoplus pre-insulated steel pipes are bonded piping systems consisting of a steel carrier pipe, polyurethane insulation and impact-resistant and break-proof HDPE jacket pipes – bonded firmly together into a robust sandwich structure.

Steel pipes are insulated with polyurethane foam blown with cyclopentane. This provides optimal insulation value and high compressive strength. Our pre-insulated pipes are suitable for continuous operating temperatures of 120°C (single pipes) and 120°C (double pipes).

We provide single steel pipe dimensions up to ø1200. Steel pipes with jacket dimensions ≤ ø355mm are available as energy-saving continually manufactured pipes with an integrated diffusion barrier between jacket pipe and polyurethane foam. The diffusion barrier protects the foam in isoplus’ pre-insulated pipes against ageing and keeps the heat loss low throughout the service life of the piping system.

Because of the wall thickness, jacket pipes in dimensions > ø355 provide a natural diffusion barrier.


Low heat loss and reduced costs with double pipes

Double pipe consists of two steel pipes – one flow pipe and one return pipe – insulated in the same HDPE jacket pipe. We can provide double pipes in dimensions up to ø273. Like pre-insulated single pipes, they are efficiently insulated with polyurethane foam and available with diffusion barrier.

The pipe structure ensures improved insulation and, thus, also lower heat loss than single pipes, while the diffusion barrier ensures a permanently low heat loss throughout the service life of the pipe system.

Double pipes are a compact solution, that takes up less space in the pipe trenches and requires fewer joints and assemblies. This also means less excavation work and increased reliability.


Leak detection system

If you require electronic leak detection in your district heating system, isoplus can deliver steel pipes with two copper wires integrated to connect with a leak detection system.



District heating, district cooling, solar heating, community heating, industry.

Carrier pipe material: Steel P235GH
Jacket pipe material: HDPE
Insulation: Polyurethane foam, blown with cyclopentane

Max. continuous operating temperature single pipes 120°C
Max. continuous operating temperature double pipes 120°C

Operating pressure: 16 bar
Delivered lengths: 6, 12 og 16 m
Dimensions: 20-600 (25-200 continually)

At isoplus you can always get professional support from project start until the piping system is installed.

We can help with turnkey solutions, planning, design calculations, feasibility study, trenchless technology, tool hire, alarm report, planned preventative maintenance, installation of joints and installation of leak detection system.

Read more about isoplus service & support.

Contact us

T  +44 1302 276976

Find your local sales office

Case references

34 km of district heating pipelines in the Netherlands

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Green transition in Gentofte, Greater Copenhagen

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District heating right on time thanks to pragmatic co-operation

 2021 was not the easiest year for planning and implementing large projects. But thanks to a flexible cooperation, TVIS still managed to advance 28 km further towards green economy. When district heating has to move over long stretches in the Triangle Region, the heat...

Unique solution in glasgow

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Over the last decade, Norway has made large investments in environmental district heating. Previously, Norway had access to very cheap electricity based on hydropower but the past 10 years' increasing electricity prices and growing urbanization have made district...

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District heating under the inlet in Hadsund

Establishing a 300-meter district heating pipeline may not sound all that spectacular, but there was something special about this project, when the southern part of Hadsund was connected to the northern city's district heating. The pipe had to be laid 1 meter below...

Trenchless technology to large project in Horsens

When 200 km of pipes and 180 km of service connections is to be buried, it is impossible to avoid inconveniences for the citizens. Many roads need to be dug up, which can cause traffic issues, broken roads, and frustrated citizens. In order to protect the surrounding...

Innovative project with new energy station in Tårnby

Tårnby Public Utility paves the way with a new visionary project in which an energy station will become the new gathering point for the area's district heating and cooling. Here the two systems will utilize the energy from the waste water. The plant will be the first...

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