Installing a safe pipe system that is compliant and efficient starts by selecting the right product for the project. Suitable pipes will contribute to increases in the energy efficiency of a building, reducing management costs to a minimum whilst offering the final user a more comfortable environment. Among the factors to consider are the temperatures that the pipe can handle and its resistance to cold.

Multi-layer pipes for heating and hydro sanitary systems, including potable water, are a versatile option that combines the benefits of metallic and polymeric materials for unparalleled resistance in any field of use.

Multi-layer pipes by Aquatechnik: the winning stratification plastic-metal

A multi-layer pipe is made of three different layers joined by two layers of adhesive that combine the strengths of metal with those of plastic materials. This pipe composition was conceived to satisfy the requirements of designers and installers by bypassing the lack of raw materials for a result that guarantees high resistance and performance.

Aquatechnik’s multi-calor pipe is formed with a particular extrusion technique, starting with the internal layer of the pipe that is created in the first phase by merging cross-linked polyethylene with additives and catalysts. The second extruder applies an adhesive layer and an aluminium layer. After the perfect calibration of the latter, TIG sealing allows thickness uniformity along the pipe circumference and in the sealing point. Subsequently, the third extruder covers the aluminium layer with adhesive to attach the final layer of cross-linked polyethylene.

The stratification PEX-Al-PEX grants notable advantages to Aquatechnik’s multi-calor pipe: it is resistant to corrosion, hygienic and not permeable to oxygen and light. It has a reduced thermal expansion compared to most plastic materials and keeps heat thanks to its composition. It offers a resistant and long-lasting system like metal pipes but is lighter and more flexible. It is a winning combination that guarantees an efficient installation and overcomes many specific challenges of the materials that could cause significant costs or malfunctions to the system.

Features of resistance: the temperatures of multi-layers

Aquatechnik’s multi-layer pipe has an expected lifespan of at least 50 years at a pressure of 10 bar and continuous temperatures of 70°C with peaks of 95°C, as requested by the norm UNI EN 21003. For temperatures below 95°C, pipes can resist pressures above 10 bar, maintaining reliability over time and increasing their expected life.

In extreme weather conditions, multi-layer pipes by Aquatechnik can work up to minimum temperatures of -45°C. For operation below 0°C, it is necessary to use anti-freezing or glycol additives.

Multi-calor pipes working conditions are shown in the table below:

Multi-calor pipes are certified for all four classes of application for the aforementioned international norm UNI EN 21003 for pressures up to 10 bar.

Multi-calor pipes are available pre-insulated for heating and hydro sanitary systems at high temperatures for energy containment. The isoline version of the pipe is coated with cell-expanded polyethylene with a resistance factor against diffusion of steam of around 5000 µ and thermal conductivity particularly low of λ=0,040 W/mk. Multi-calor pipes are also available in isoline plus, which coating has a thermal conductivity λ equal to 0,035 W/mk.

Cold resistance of multi-layer pipes made of Cross-linked polyethylene

Cross-linked polyethylene (PEX) is a modified material in the molecular structure through the formation of lateral chemical links in the polymeric chains. Crosslinking improves performance, including resistance to high temperatures, chemicals and abrasion. The intrinsic flexibility of cross-linked polyethylene also grants excellent resistance to ruptures from freezing. This means that if water or other fluids freeze inside PEX pipes, the material’s elasticity allows, within certain limits, to expand without bending or breaking and reset to the original diameter after defrosting.

There are variables in an installation that can cause a breakdown of PEX in certain situations. When installed outside, there must be adequate thermal insulation to avoid ice formation. How much isolation or anti-freeze is necessary to guarantee adequate protection depends on the building’s location and climate zone. Moreover, local building norms and regulations are applied. To consider, in designing, also that properties of materials of multi-layer pipes with PE-X offer advantages when exposed to freezing conditions, thanks to a thermal conductivity inferior to that of metal materials, which reduces the index of thermal exchange and can increase the time necessary to freeze the fluid inside the system.

The challenges for the hydrothermal sanitary sector with multi-layer pipes

Offering the best of pipes among polymeric and metal materials, a multi-layer pipe is the perfect answer to the demands of designers and installers that search for performing and efficient solutions. With applications in any sector, from the civilian to the industrial and tertiary, multi-calor are suited to be installed free pose and inside walls. The wide range of safety fittings for multi-layer pipes completes the offer of Aquatechnik to satisfy the market demands in a synergy of resistance and flexibility in any working condition of a system.