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A reinforced pre-insulated polymer pipe system for district heating applications

FibreFlex is the next generation of highly-efficient, flexible pre-insulated pipe systems for district heating applications. With a reinforced polymer service pipe, the system offers higher working pressures than conventional PE-Xa systems - 10 bar at temperatures up to 95°C - and improved safety factors when operating at lower pressures.

The FibreFlex system’s innovative service pipe has a multi-layered construction, comprising of a PE-Xa pipe at its core, a layer of high-modulus aramid reinforcing mesh and an EVOH oxygen diffusion barrier. This is encased in a bonded layer of closed-cell PUR foam insulation, protected by a tough, yet flexible, corrugated LDPE outer casing. Due to its excellent mechanical strength, the service pipe has a reduced wall thickness, which results in a thicker layer of PUR insulation which can lower heat loss by as much as 17% when compared to conventional pre-insulated PE-Xa systems.

Easy to install with a full range of components and fittings available, the system is supplied in coils of up to 550m in length, which minimises on-site joints and lowers installation costs. The system is offered with options for single or twin service pipe configurations within a single outer casing.


Buried District Heating Networks

Diameter Range 25 mm to 160 mm (OD) (service pipe) Bespoke: No
Max Operating Pressure 10 bar
Lengths Up to 550 m coils Bespoke: Yes
Compliance / Approvals OFI CERT ZG 200-2 Class A with the technical specification in line with EN 15632-2
Approved Fittings & Jointing Techniques

Axial compression service pipe joints


New installations
System extensions
System replacements

Jointing Techniques

Axial compression for service pipe joints
Mechanical joint on outer casing
Optional heat-shrink casing joint

Jointing Equipment Axial compression tooling with hydraulic pump (manual or electrically operated), hand tools for service pipe preparation and gas burner for optional heat-shrink casing joint
Installation Techniques


Maximum Temperature (peak):


Thermal Conductivity:

≤0.021 W/mK at 50°C

Service pipe configuration:

Single and Twin

Pipe material:

Multi-layer composition with PE-Xa liner, high-modulus aramid reinforcing mesh, EVOH diffusion barrier, PUR insulation and LDPE outer casing

Pipe colour:

Yellow (service pipe), black with longitudinal yellow stripes (outer casing)