Pre-insulated pipe CALPEX DUO 25+20x91: Pex-a pipe 25x3.5+20x2.8mm, OD 91mm, 10 bar, 95°C, double, thermal insulation with PUR foam, with corrugated LLDPE outer jacket. 1007432

Pre-insulated pipe for efficient heating and district heating installations

The CALPEX DUO pre-insulated pipe is an advanced solution for central heating and domestic hot water installations, combining flexibility, durability and energy efficiency. This system works well in both new and modernized buildings, as well as in small and medium-sized heat pump networks and local district heating networks. The two-pipe (DUO) design allows for the simultaneous transport of two media – e.g. supply and return – in one pipe, which significantly simplifies installation and reduces costs.

Construction and properties

The CALPEX DUO pipe consists of several key elements, providing it with unique properties:

• Inner pipe: Made of cross-linked polyethylene PEX with an EVOH anti-diffusion layer, preventing oxygen from penetrating the installation. This guarantees long-term protection against corrosion of system components.
• Thermal insulation: Freon-free polyurethane (PUR) foam with high insulation properties minimizes heat loss during medium transport, resulting in energy savings.
• Outer jacket: Durable and resistant to mechanical damage jacket made of LLDPE polyethylene with a corrugated surface. The corrugation increases the flexibility of the pipe, making installation easier and protecting against damage during use. Additionally, the jacket is resistant to UV radiation, allowing the pipe to be used in outdoor installations.

This construction provides resistance to aggressive media, low pressure losses and very good chemical and mechanical resistance. The pipe is designed for continuous operation at temperatures up to 90°C and momentary up to 95°C, and its working pressure is 10 bar.

Applications and benefits

The CALPEX DUO pre-insulated pipe finds wide application in:

• Supplying heat to residential and commercial buildings.
• Renovations of existing heating installations.
• Heat pump networks (air-to-water).
• Local district heating networks.
• Underfloor and wall low-temperature heating installations.

Benefits for the installer:

• Easy installation thanks to the flexibility of the pipe and the corrugated surface of the outer jacket.
• Fast connections thanks to a wide range of system accessories.
• The pipe can be cut to size – pricing per running meter facilitates cost calculation.
• Reduced risk of damage during transport and installation thanks to the durable protective jacket.

Benefits for the end user:

• Low heat loss – energy savings and lower heating bills.
• Long-term reliability – protection against corrosion and mechanical damage.
• Quiet operation of the installation – no condensate on the pipe surface thanks to effective thermal insulation.
• Comfort of use – stable temperature in rooms thanks to minimal fluctuations in the heating medium temperature.

It is important to remember the specification of the pipe dimensions when ordering: nominal diameter (DN), outer diameters of the conduit pipes and the outer diameter of the entire pre-insulated pipe (d). In the case of the CALPEX DUO 25+20x91 model, we have two inner pipes with diameters of 25mm and 20mm, and the outer diameter of the entire pipe is 91mm.