FLEX Products
At RK Infra, we deliver high-performance, durable, and innovative pre-insulated flexible pipe solutions designed to meet the evolving needs of modern industries and communities. Our product range combines advanced engineering, sustainable materials, and cutting-edge technology to ensure superior quality and long-lasting performance in every project.
Pre-insulated, flexible pipe system with polyethylene service pipes, and PUR thermal insulation.
The advantages of HeatFlex include quick installation, narrow pipe trenches, tight bending radii and the twin pipe system. The highly efficient pipe system alson impresses with an excellent thermal conductivity value of 0.021 W / mK.
For a further reduction in heat loss, a second insulation series with higher insulation is now available
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Service Pipe: Made from PE-Xa (cross-linked polyethylene), designed for flexibility and long service life.
Oxygen Diffusion Barrier: Prevents oxygen ingress, protecting heating systems from corrosion.
Thermal Insulation: CFC-free, cyclopenthane-based PUR (Polyurethane) foam, with an exceptionally low thermal conductivity of 0.021 W/mK, ensuring energy efficiency.
Casing: Corrugated PE-LLD (linear low-density polyethylene) outer casing for mechanical protection and flexibility.
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Max continuous operating temperature: +80 °C
Max operating temperature: +95 °C (with variable profiles according to ISO 13760)
Operating pressure: 6 bar at 80 °C
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Designed according to EN 15632-2 for a minimum of 30 years, with defined temperature profiles
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Insulation Levels:
Standard series
IS2 – Higher insulation option for extra energy efficiency and reduced heat loss.
Length: Pipes can be delivered in standard coil lengths or custom cut lengths per project needs.
Pipe Configurations:
UNO (single pipe)
DUO (twin pipe) for supply & return in one casing
Temperature/Time Profiles: Systems can be designed for other operating profiles under ISO 13760 (Miner’s rule), allowing tailored performance.
Accessories & Fittings: Optionally offer compatible fittings, end caps, joint kits, or connectors.
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Standard Coil Sizes: Max coil dimensions are 2950 mm × 1200 mm (height × width).
Delivery Formats:
Coils for standard lengths
Cut-to-length delivery on request
Storage & Handling: The flexible pipes allow for efficient transport and easier on-site logistics compared to rigid systems
Pre-insulated, flexible pipe system with polyethylene medium pipes and high-performance PUR thermal insulation.
The Service Pipe forms the core of the HeatFlex system, delivering reliable performance for district heating, cooling, and domestic hot water applications. Its robust construction allows for narrow pipe trenches, tight bending radii, and quick installation, making it ideal for modern energy distribution networks.
The system’s highly efficient thermal insulation achieves a thermal conductivity of 0.021 W/m·K, minimising energy loss during transmission. For projects requiring even higher thermal performance, a second insulation series with increased insulation thickness is available to further reduce heat loss.
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The Medium Pipe consists of polyethylene service pipes designed for long-lasting, flexible operation:
Service Pipe: High-density polyethylene (PE), optimised for heat distribution networks.
Insulation: CFC-free, cyclopentane-based PUR foam providing excellent thermal efficiency.
Outer Casing (in full HeatFlex system): Corrugated PE-LLD for mechanical protection.
These materials combine to provide a durable, corrosion-resistant, and energy-efficient piping solution.
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The Medium Pipe is engineered for consistent performance under standard district heating conditions:
Typical Operating Temperature: Up to 80 °C continuous.
Maximum Operating Temperature: Up to 95 °C (short-term, variable).
Operating Pressure: Typically 6–10 bar, depending on configuration.
This makes it well-suited for low- to medium-temperature networks, domestic hot water distribution, and similar applications.
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The Medium Pipe is designed according to EN 15632-2, ensuring a long operational lifespan:
Service Life: Up to 50 years under standard temperature/time profiles.
Performance Verification: Based on ISO 13760 (Miner’s rule) for temperature/time load calculations.
Resistant to corrosion, thermal aging, and mechanical stresses, making it a robust long-term solution for buried installations.
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The Medium Pipe can be configured to match a wide range of project requirements:
Available in multiple diameters for different flow demands.
Option to select standard or increased insulation thickness for enhanced thermal performance.
Compatible with custom coil lengths to minimise joints on site and speed up installation.
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Standard Maxi-Coil Dimensions: 2950 mm (H) × 1200 mm (W).
Project Coils: Available up to 2950 mm (H) × 2400 mm (W) for extended lengths.
Supplied in long, flexible coils, allowing for fewer connection points and fast trench installation.
Delivered ready for integration within HeatFlex pre-insulated systems.
Pre-insulated, flexible pipe system, with a service pipe made of fibrer-reinforced, crosslinked polyethylene and PUR thermal insulation.
Thanks to the aramid fiber mesh, the pipe wall thicknesses could also be reduced and, due to the resulting smaller outside diameter, the insulation could be improved.
Compared to conventional flexible pipe systems, media can be transported at a pressure of 10 bar at a continuous operating temperature of + 80 ° C
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Service Pipe: Made from PE-Xa (cross-linked polyethylene), designed for flexibility and long service life.
Oxygen Diffusion Barrier: Prevents oxygen ingress, protecting heating systems from corrosion.
Thermal Insulation: CFC-free, cyclopenthane-based PUR (Polyurethane) foam, with an exceptionally low thermal conductivity of 0.021 W/mK, ensuring energy efficiency.
Casing: Corrugated PE-LLD (linear low-density polyethylene) outer casing for mechanical protection and flexibility.
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Max continuous operating temperature: +80 °C
Max operating temperature: +95 °C (with variable profiles according to ISO 13760)
Operating pressure: 6 bar at 80 °C
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Designed according to EN 15632-2 for a minimum of 30 years, with defined temperature profiles
-
Insulation Levels:
Standard series
IS2 – Higher insulation option for extra energy efficiency and reduced heat loss.
Length: Pipes can be delivered in standard coil lengths or custom cut lengths per project needs.
Pipe Configurations:
UNO (single pipe)
DUO (twin pipe) for supply & return in one casing
Temperature/Time Profiles: Systems can be designed for other operating profiles under ISO 13760 (Miner’s rule), allowing tailored performance.
Accessories & Fittings: Optionally offer compatible fittings, end caps, joint kits, or connectors.
-
Standard Coil Sizes: Max coil dimensions are 2950 mm × 1200 mm (height × width).
Delivery Formats:
Coils for standard lengths
Cut-to-length delivery on request
Storage & Handling: The flexible pipes allow for efficient transport and easier on-site logistics compared to rigid systems
Pre-insulated, flexible pipe system with fiber-reinforced medium pipe for use up to 115°C and 10 bar.
Thanks to the high temperature aramid fiber mesh, the FibreFlex Pro pipe system can be used up to a maximum operating temperature of 115 ° C and a pressure of up to 10 bar.
The FibreFlex Pro pipe system thus combines the advantages of a flexible pipe system with the operating properties of steel pipe systems and is therefore an innovative, cost-effective alternative.
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Fibreflex is a pre-insulated, flexible pipe system designed for district heating and similar applications. Its layered structure ensures durability, thermal efficiency, and flexibility:
Service Pipe: PE-Xa (crosslinked polyethylene) reinforced with aramid fibre mesh for enhanced strength and reduced wall thickness.
Adhesive Layers: Applied between layers to ensure strong bonding and incorporate the oxygen diffusion barrier.
Thermal Insulation: High-quality, CFC-free polyurethane foam (PUR), cyclopentane-based, ensuring low thermal conductivity.
Outer Casing: Corrugated PE-LLD (polyethylene, linear low density) provides mechanical protection and flexibility
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Fibreflex is designed to perform reliably under demanding thermal and pressure conditions:
Max. Continuous Operating Temperature: +80 °C
Max. Operating Temperature: +95 °C (variable, short-term)
Operating Pressure: 10 bar
Thermal Conductivity: 0.021 W/mK
This performance exceeds conventional flexible systems, allowing transport at 10 bar and 80 °C continuously
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The system is engineered for long-term performance:
Designed according to EN 15632-2 for a 50-year service life.
Temperature/time profiles are based on ISO 13760 (Miner’s rule), allowing for different seasonal operating regimes (e.g., winter 85 °C / summer 75 °C).
Example profile: 29 years at 80 °C + 1 year at 90 °C + 100 hours at 95 °C.
The maximum operating temperature must not exceed 95 °C
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Fibreflex offers a range of dimensions and configurations to suit project-specific needs:
Single (UNO) and Twin (DUO) configurations available.
Pipe sizes from 25 mm to 160 mm service pipe diameters.
Multiple insulation thicknesses and casing diameters (e.g., 76 mm to 225 mm).
Custom coil lengths available for project-specific requirements, beyond standard maxi-coil dimensions
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Standard Maxi-Coil Dimensions: 2950 mm (H) × 1200 mm (W).
Project Coils: Available up to 2950 mm (H) × 2400 mm (W) for longer continuous lengths.
A variety of coil lengths depending on pipe dimension (e.g., up to 570 m for 25–40 mm sizes).
Flexible logistics to support fast, on-site installation
Pre-insulated, flexible pipe system with fiber-reinforced medium pipe for use up to 115°C and 16 bar.
Thanks to the finer-meshed high-temperature fiber mesh made of aramid, the FibreFlex Pro 16 pipe system can be used up to a maximum operating temperature of 115 ° C and a pressure of up to 16 bar.
The FibreFlex Pro pipe system thus combines the advantages of a flexible pipe system with the operating properties of steel pipe systems and therefore represents an innovative, cost-effective alternative.
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FibreFlex Pro 16 is a pre-insulated, flexible pipe system featuring a fiber-reinforced medium pipe. Its advanced material structure ensures reliable performance at elevated temperatures and pressures:
Service Pipe: PE-Xa, reinforced with a finer-meshed, high-temperature aramid fiber mesh for maximum strength and stability.
Thermal Insulation: High-quality CFC-free PUR foam, cyclopentane-based, for excellent thermal efficiency.
Outer Casing: Corrugated PE-LLD provides mechanical protection and flexibility.
This material combination gives FibreFlex Pro 16 the operational properties of steel systems while maintaining the installation advantages of flexible piping.
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FibreFlex Pro 16 is designed for high-performance applications, offering significantly improved thermal and pressure resistance compared to standard flexible pipes:
Maximum Operating Temperature: 115 °C
Operating Pressure: Up to 16 bar
This is achieved through the use of high-temperature aramid reinforcement, enabling the system to handle demanding district heating and hot water distribution networks with reliability.
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The system is engineered for long-term durability under high-stress conditions:
Designed to match the service life expectations of steel systems while retaining flexibility advantages.
The aramid reinforcement allows the system to maintain structural integrity under high temperature and pressure profiles, supporting extended operational lifespans.
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FibreFlex Pro 16 is available in a range of dimensions and configurations, tailored to meet project-specific requirements:
Available in single (UNO) and twin (DUO) configurations.
A variety of pipe diameters and insulation thicknesses to suit different flow rates and installation environments.
Project-specific coil lengths available upon request to optimise installation efficiency.
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Standard Maxi-Coil Dimensions: 2950 mm (H) × 1200 mm (W).
Project Coils: Available up to 2950 mm (H) × 2400 mm (W) for extended lengths.
Various coil lengths depending on pipe size, allowing for efficient, joint-minimised installations on site.
Accessories
FibreFlex / FibreFlex Pro factory pre-insulated parts
PE-Xa pipes (SDR11, SDR7.4) are connected via press or clamp connectors (welding adapters, thread adapters, couplings, bends, T-pieces).
A press tool is required to install the fittings. These can be obtained from RK Infra. No special tools are required to install the clamp connections. The clamping force is applied via the outer sleeve by tightening a clamping screw. A conventional hex wrench can be used for this.
FibreFlex & FibreFlex Pro Accessories
FibreFlex / FibreFlex Pro press fittings have an additional polymer crimp sleeve between the sliding sleeve and the service pipe. As a result, the support bushing can be inserted directly into the pipe ends during installation without widening. Up to size 110, standard pressing tools such as for PE-Xa pipes (SDR11) can be used. The RK Infra pressing tool is available for larger dimensions. The pressing point is insulated with joint system.
HeatFlex Accessories
To reduce welding and assembly work on the construction site, a large selection of pre-insulated steel fittings is available. The FibreFlex / FibreFlex Pro press transitions are welded onto the steel parts and can be pressed directly.
Joint systems are used to insulate connection points.
Half-shells are available in various configurations for our flexible plastic pipe systems. This innovative CLICK system guarantees the highest construction site quality without time-consuming gluing, screwing or shrinking with secure connection technology and the best thermal insulation properties.
Half shells for HeatFlex, FibreFlex / FibreFlex Pro
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