An aluminium membrane between the outer casing and the insulation material makes the LOGSTOR FlexPipes - SteelFlex, AluFlex and CuFlex - 100% diffusion-tight. It prevents the insulation gases from diffusing out through the plastic casing and being replaced by air with inferior insulation properties. In PexFlex a polymer diffusion bar-rier is embedded which reduces the diffusion of insulation gases, while letting water vapour exit. The pipes therefore maintain their insulation property throughout their en-tire service life. The FlexPipe systems are available in more insulation series, so they can be opti-mised for all operational conditions. All FlexPipes have a smooth outer casing. They are consequently especially suitable for tunnelling which is the technique used, when excavation is undesirable.

Reduced heat loss
Compared to traditional, preinsulated flexible pipes our diffusion-tight FlexPipes reduce the heat loss considerably during the entire service life.



The curve (ill. 1) illustrates the ageing course of the insulation foam and consequently the heat loss of FlexPipes with and without diffusion barrier. Especially in FlexPipes, used for district heating house entries the relative heat loss is rather high, primarily due to the relation between water quantity and pipe surface. So the financial gain of using diffusion-tight FlexPipes from LOGSTOR is considerable.



The consumers as well as the DH stations benefit from the optimum reduction in the heat loss (ill. 2) and improved economy – and naturally it also means reduced environmental impact.

Complete program
LOGSTOR offers a complete program of diffusion-tight FlexPipes, of which three in particular differ as regards service pipe material and jointing technique. SteelFlex, AluFlex and CuFlex offer the possibility to choose the solution, which complies with the requirements to e.g. pressure, temperature and insulation.

Easy to install with the LOGSTOR casing joint systems
LOGSTOR offers various casing joint systems which makes it simple, quick and safe to make house entries with flexible pipes – from new as well as existing distribution pipelines:

• The casing joint systems of cross-linked PE (PEX) are easy to install and they fit all tolerances and angular displacements. In addition they are unsurpassed resistant to mechanical and chemical impacts.
• LOGSTOR’s SteelJoint system is made of steel, which is 100% covered with polyethylene. It is sturdy and resistant towards terrestrial impacts and it requires fewer joints in the pipe system than many other casing joint systems. The SteelJoint system also includes branches from TwinPipes to FlexPipes.
• LOGSTOR BandJoint system is made of the same material as the outer casing. It is joined by means of fusion welding where the BandJoint and outer casing melt together in a computer-controlled process into a bonded sandwich construction. The BandJoint system also includes branches from TwinPipes to FlexPipes.

All the systems may be pressure tested and insulated subsequently with foam packs. On all four service pipes hot tapping may be carried out on systems in operation – without interrupting the operation.

House installation – simple and discrete
PexFlex, SteelFlex, AluFlex and CuFlex can be led into a house without additional joints on the service pipe. There are a number of out- and indoor solutions, ensuring an optimum house entry and careful completion of the installation.

Installation tools
For all LOGSTOR’s FlexPipe systems the necessary tools are available, i.a. specially designed bending tools as well as a trailer for the transport and straightening of the FlexPipe coils. LOGSTOR FlexPipes are available in lengths of 50 and 100 m and regardless of dimension we recommend installation from a trailer, equipped with a straightener. For PexFlex and AluFlex standard tools for the compression couplings are available.

PexFlex
The service pipe is flexible and can withstand peak temperatures up to 95°C or 85°C continuous.
It is suitable for house entries and secondary systems.

SteelFlex
The service pipe is made of cold-rolled steel, which is the traditional material for district heating pipes for transmission as well as distribution systems. SteelFlex is suitable for house entries in DH systems with high temperatures and pressure and the jointing method is traditional welding.

AluFlex
AluFlex is a FlexPipe, combining the advantages of the smooth surface of the plastic pipe with the durability and tightness of the metal pipe. The service pipe is a sandwich construction, consisting of an aluminium pipe, coated inside with PEX and outside with PE. The aluminium core ensures 100% against oxygen and water vapour diffusion and makes the pipe form stable during installation in the trench and mounting the power transmitting compression couplings. AluFlex is suitable for distribution systems for district heating and domestic water.

CuFlex
For many years soft copper has been used for service pipes in distribution systems for district heating as well as hot and cold domestic water. CuFlex is a flexible pipe – suitable for systems with high temperatures and pressure. The jointing method is hard soldering or compression fittings.