SINIKON, a company producing pipes and fittings made of modern polymer materials for sewage and water supply systems, launched a new product to the Russian market in 2020 - SINIKON THERMOLINE PE-Xb EVOH pipes made of cross-linked polyethylene with a PEX-b/EVOH barrier layer. These pipes are designed for use in low-temperature heating, water supply and especially in water underfloor heating systems.

"The use of PE-Xb pipes in operation leads to cheaper production of engineering systems, faster installation, environmental friendliness and safety. All these factors lead to an improved quality of life. Due to its reliability and low cost, pipes made of cross-linked polyethylene are used more and more often for heating and water supply systems," the company says.

SINIKON THERMOLINE PE-Xb pipes are made of high-density polyethylene with silane crosslinking. Unlike standard grades of polyethylene whose use is limited to maximum temperatures that will be much lower than the melting point, cross-linked polyethylene is notable for its ability to melt and form at elevated temperatures. At elevated temperatures cross-linked polyethylene easily deforms: a temporary temperature jump can lead to complete destruction of the product. By cross-linking the linear molecules, the thermal dimensional stability of polyethylene (PEX) can be significantly improved. This enables PEX products to be used in applications with higher temperature requirements that exceed the temperature limits of normal thermoplastic grades.

Silane (silicon-hydrogen compounds) crosslinking method - PEX-b has proven to be the most economical method of crosslinking polyethylene for cable and pipe applications. The fused polymer retains its dimensional stability and the deformation of the cross-linked polyethylene is minimal.

Compared to other crosslinking technologies, such as peroxide (PEX-a) or radiation (PEX-c) curing, crosslinking with organofunctional silanes has some major advantages:

- Sustainable and economical process;

- Environmentally friendly technology;

- Crosslinking takes place outside of the extruder;

- Low capital costs;

- High flexibility due to wider process window;

- High throughput;

- Small silane volumes result in excellent quality.

Thus, pipes made of cross-linked polyethylene have low hydraulic resistance, are not subject to corrosion, overgrowth, chemically and electrically inert, have elasticity, temperature memory and do not break when water freezes. On the outside SINIKON THERMOLINE PE-Xb pipes are coated with an EVOH layer (ethylene-vinyl alcohol) that prevents diffusion of oxygen molecules into the pipe, thus significantly reducing cross-sectional overgrowth and heating equipment wear due to oxidation processes.

SINIKON THERMOLINE PE-Xb EVOH pipes are manufactured according to GOST 32415-2013, which establishes requirements for pipes made of basic polymer materials, including cross-linked polyethylene (PE-X). The standard regulates the parameters determining the service life of pipelines in cold water supply, hot water supply and heating systems:

- long-term hydrostatic strength of materials as a function of the time-stress relationship in the pipe wall;

- temperature (long-term strength reference diagrams);

- operating conditions (classes) determined by the complex of temperatures and times of their exposure, as well as the values of pressures.

Now the plant manufactures PE-Xb pipes with diameters of 16 mm and 20 mm with lengths of 100, 200, 400 meters and 100, 200, 300 meters respectively. The thickness of all pipes is 2.0 millimeters.

"When talking about the characteristics of PEX pipes, it is important to consider the operating class of pipes made of this polymer material. In addition to strength characteristics, which vary depending on the type of pipe production, there are also so-called operation classes - standardized temperature and time of use conditions for the pipes. SINIKON THERMOLINE PE-Xb EVOH pipes can be used in operation classes 1, 2, 4 and 5," the company says.

A 16 mm diameter pipe is applied in operation classes 1 (hot water supply (60°)), 2 (hot water supply (70°)), 4 (low-temperature heating with radiators) with an operating pressure of 1.0 MPa (10 bar), class 5 (high-temperature heating with radiators) - 0.8 MPa (8 bar). 20 mm diameter pipe in classes 1 (hot water supply (60°)), 2 (hot water supply (70°)), 4 (low-temperature heating with radiators) with operating pressure of 0.8 MPa (8 bar), class 5 (high-temperature heating with radiators) - 0.6 MPa (6 bar).

There are six sub-grades of pipes in total. All these grades do not influence the quality of the pipe and only indicate the modes of pipe operation and its operating temperature in relation to the service life of the material.

When used in accordance with the class, SINIKON THERMOLINE PE-Xb EVOH pipes can last up to 50 years.