Flexalen® PU is a high-performance, pre-insulated plastic piping system for medium to large heating networks where maximum energy efficiency and flexibility must go hand in hand. The system combines PB-1 service pipes, bonded polyurethane (PUR) foam insulation with excellent λ-values, and protective PE/HDPE casings to deliver the highest insulation class for plastic pipes at 95°C/8 bar.
Highest insulation class for efficient heating networks.
Flexalen® PU, available in flexible PU coils and PU sticks (up to DN300), give designers freedom to combine long coil lengths with rigid sticks within one compatible system. The bonded PUR insulation provides very low thermal conductivity, λ ≤ 0.023 W/m·K at 50°C, ensuring low heat losses and excellent network efficiency.
With service pipes up to OD315 mm and a pressure/temperature rating of 95°C/8 bar, Flexalen® PU offers large network capacity and long service life for both conventional and low-temperature grids. The system is produced according to EN 15632 and EN ISO 15876, uses closed-cell, CFC-free PUR foam, and is fully compatible with Flexalen® 600—allowing designers to combine maximum insulation for main lines with highly flexible Flexalen 600 house connections in one hybrid solution.
Performance you can trust
Why choose Flexalen® PU
Select Flexalen® PU when heating networks require the highest insulation class, large capacity, and seamless compatibility with flexible Flexalen 600.
Highest insulation class
Bonded PUR foam insulation with very low thermal conductivity delivers the highest insulation class for plastic pre-insulated systems, ideal for low-temperature and energy-efficient heating grids.
Large network capacity
PB-1 service pipes up to OD315 mm and 95°C/8 bar rating provide high transport capacity and reliable operation in medium to large heating networks.
Flexible and semi-flexible options
Fully flexible PU coils (DN20–DN80 single, DN20–DN65 double) and semi-flexible PU SL sticks (up to DN300) allow optimal routing, reduced fittings, and efficient installation.
Compatible hybrid networks
Full material and connection compatibility with Flexalen® 600 enables hybrid networks that combine best-in-class insulation on main lines with highly flexible house connections.
Safe, homogeneous welding
PB-1 service pipes with EVOH layer are fully weldable, creating homogeneous joints without foreign materials and supporting long-term leak-tightness and reliability.
Supported by design tools and services
Thermaflex provides integrated network design support, calculation tools for heat loss and pressure drop, training, and on-site assistance to ensure correct specification and efficient installation.
Flexalen® PU Single
Flexalen® PU Double
Straight Length Single
Flexalen® PU Straight Length Double
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Thermaflex combines decades of expertise with a commitment to sustainable innovation. As your trusted partner, we deliver more than products, we provide comprehensive technical support, proven solutions, and collaborative partnerships that help you achieve project success, regulatory compliance, and long-term operational efficiency across various markets and applications worldwide.
Trusted benefits
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FREE WHITEPAPER
Connection Methods in District Heating and Cooling Networks
Discover the optimal connection methods for district heating and cooling networks. This guide covers mechanical connections, electrofusion, butt, and socket welding techniques—plus prefabrication strategies to reduce on-site work and project costs.
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