PU Foam Insulated Pipe
PU foam insulated pipes are factory-prefabricated bonded piping systems consisting of a steel carrier pipe, rigid polyurethane (PU) foam insulation, and a high-density polyethylene (HDPE) outer jacket. The three-layer bonded construction ensures that the carrier pipe, insulation, and jacket act as a single composite unit, accommodating thermal expansion and contraction without separation.
Manufactured in accordance with CJ/T114 and EN 253 standards, our pre-insulated pipes achieve thermal conductivity values as low as 0.027 W/m\u00b7K, delivering exceptional energy efficiency for district heating networks. The system includes leak detection wires embedded in the insulation for continuous monitoring of pipe integrity. Available in standard and reinforced insulation thicknesses for operating temperatures up to 140\u00b0C continuous and 150\u00b0C peak.
CJ/T114 / EN 253
Steel + PU + HDPE
DN20-DN1200
Applications
- District heating and cooling networks
- Geothermal energy transmission
- Industrial steam and condensate lines
- Chilled water distribution
- Oil and chemical product temperature maintenance
Quality Assurance
All PU Foam Insulated Pipe products undergo NDT testing with MTC per EN 10204 3.1. Third-party inspection by SGS, BV, TUV available.
PU Foam Insulated Pipe Technical Specifications
Pre-insulated polyurethane (PU/PIR) foam pipe consists of a carrier pipe, polyurethane foam insulation, and an outer HDPE casing. This system is the international standard for district heating and cooling, offering thermal conductivity as low as 0.024 W/mK and 30-50 year service life.
| Parameter | Specification |
|---|---|
| Standard | EN 253 / CJ/T 114 / DIN 30674 |
| Carrier Pipe | Seamless steel (API 5L), ERW steel, or copper |
| Insulation | PU foam (polyurethane), density 60-80 kg/m3 |
| Thermal Conductivity | 0.024 W/mK (at 50C mean temperature) |
| Casing | HDPE (high-density polyethylene), black, min. 3mm |
| Size Range | DN20 (3/4 inch) to DN1200 (48 inch) |
| Service Temp | Continuous 130C, peak 140C (higher with special foams) |
Manufacturing Process
Pre-insulated pipe is manufactured by injecting PU foam between the carrier pipe and HDPE casing:
- Carrier Pipe Preparation: Steel pipe cleaned, inspected, and positioned concentrically inside HDPE casing using centering spacers.
- Jacket Sealing: Ends of HDPE casing sealed with end caps, leaving injection and venting ports.
- Foam Injection: Two-component PU (polyol + isocyanate) mixed and injected, expanding to fill the annular space.
- Curing: Foam cures within minutes, forming rigid closed-cell structure with 60-80 kg/m3 density.
- Leak Detection Wire: For district heating, a copper wire embedded in foam enables leak detection via resistance measurement.
- Dimensional Check: Eccentricity, foam thickness, and casing integrity verified per EN 253.
- End Preparation: Steel pipe ends exposed (approx. 150mm) for field welding; casing ends prepared for heat-shrink sleeve sealing.
Applications & System Design
PU insulated pipe is the standard for thermal distribution systems:
- District Heating: Buried hot water lines from central plants to buildings, replacing individual boilers.
- District Cooling: Chilled water distribution for air conditioning systems, with PU insulation preventing heat gain.
- Industrial: Process hot water and steam condensate return lines.
- Oil and Gas: Subsea flowlines requiring thermal insulation to prevent wax or hydrate formation.
Design considerations include: foam compressive strength (>0.3 MPa per EN 253), water absorption (<10% by volume), and joint insulation using heat-shrink sleeves that match the pipe casing. The system is designed for direct burial, with carrier pipe in steel for high temperature or copper for small-bore domestic connections.