Plastic pipes for heating specifications. What is good about cross-linked polyethylene for heating - advantages and disadvantages of pipes Reinforced cross-linked polyethylene

wear-resistant and flexible pipes made of cross-linked polyethylene for heating are in demand in the market of pipe products. Find out what varieties of such pipes are produced and how to complete the installation in accordance with all the rules.

Polyethylene pipes for heating

Material Features

The way polyethylene is produced affects specifications finished pipe. During the production process, the material is subjected to high pressure treatment, which gives it increased strength. Supermolecular polyethylene is the result of the polymerization of ethylene. The material has a network molecular structure and additional intermolecular bonds. Therefore, it has both strength and elasticity at the same time.

The molecular model of standard polyethylene has a linear structure with weak interatomic bonds. In cross-linked polyethylene, the molecules are tightly connected to each other, and additional side bonds form a lattice similar to the structure of solids. Depending on the crosslinking technology, substances with different amounts of intermolecular bonds and different strengths are obtained.

After deformation, cross-linked polyethylene tends to return to its original shape. The most durable material is marked PEX-a. It is produced by treatment with peroxide. Products obtained in this way are resistant to cracking and do not deform due to high temperatures.

Specifications

Density - 940 kg / m 3, melting point 200-400 ° C, combustion temperature - 400 ° C, thermal conductivity 0.38 W / mK, linear expansion coefficient 0.12-0.14 mm / mk.

The degree of crosslinking affects the cost and strength characteristics. The standard indicator is in the range from 65% to 80%. Polyethylene can be silane (organsiloxanes are present in the material, the degree of crosslinking is 65%) or pyroxide (peroxides are used in the production, the degree of crosslinking is 85%). The material is also obtained using ionizing radiation (the degree of crosslinking is 60%). As a result of the application of new technologies, wide-cell "cross-linked" polyethylene is obtained.

Advantages

The material withstands a pressure of 10 atmospheres, a temperature of 95°C and does not lose strength even at sub-zero temperatures.
The inner surface of the pipe does not “overgrow” with time, does not deform during hydraulic shocks, and has dielectric properties.
The service life is 50 years. Polyethylene does not corrode and does not react with aggressive media.
Products do not contain harmful substances.
The material does not deform when frozen, has plasticity.
Moisture does not condense on the surface of the pipe.
Polyethylene pipes are suitable for both autonomous and central heating.
The price of a polyethylene pipe is lower than a metal-plastic one.

Flaws

The material is destroyed by direct sunlight.
Due to the lack of a reinforced layer, it is difficult to give the product desired shape and hard to fix.

Installation of a warm floor

Step-by-step instruction

To ensure the waterproofing of the future warm floor, the surface of the screed is leveled and covered with a polyethylene film.
To improve the thermal insulation properties, a polystyrene plate with a relief surface in the form of bosses is laid on top (a pipe is placed between the protrusions). The step between the pipes is 10-30 cm (the distance is chosen depending on the required temperature in the room and on the amount of heat loss). IN standard conditions for 1 m 2 use 5 meters of pipe.
From above, to strengthen the screed, a reinforcing mesh is placed. In order to compensate for the thermal expansion of the screed, a damping tape is laid around the entire perimeter of the room. Such a heating system can be used as an additional or as a main one. An inlet temperature of 30-40°C and a pressure of two atmospheres provide energy savings and a gentle operation of the system elements.
Connections are made with brass fittings.

Important Points

PEX cross-linked polyethylene has anti-diffusion properties that ensure tightness and uniform heat transfer.
When repairing old pipes without dismantling, the PEX pipe is pulled inside the folded steel pipeline. When the working medium is supplied, polyethylene pipes straighten out, forming a new, durable surface.
When laying heating in a wall or floor, two laying methods are used: concrete (the pipe is mounted on a grid and poured with concrete) and dry (the pipe is installed in special gutters, covered with carpet or other coating from above). The first method is more reliable. When creating a warm floor without a screed, there are also advantages: less space, and the installation speed is higher.
High-percentage cross-linking results in the most rigid but also the least flexible products.
PEx-a material has the highest melting point and impact resistance.
Such pipes are connected by press fittings and collet fittings.

Scope of application of pipes made of cross-linked polyethylene: fire extinguishing systems, gas and heat supply systems (radiator type and with geothermal heat pumps), water supply systems (with hot and cold water) and irrigation lines.

Cross-linked polyethylene pipes for heating - the pros and cons of the material, Portal about pipes

Polyethylene pipes for heating: technical characteristics, material features, installation of the "warm floor" system. Advantages and disadvantages of crosslinked

Pipes made of cross-linked polyethylene (PE-X) for heating

Metal pipes in heating systems are losing their popularity due to rapid rusting and clogging. They are replaced by cross-linked polyethylene. It's material High Quality and is now widely used in the production of pipes.

The world designation sounds like PE-X.

XLPE pipes Rehau

Types of polyethylene pipes

To begin with, it is worth saying that there are polyethylene pipes:

designed specifically for the heating system;
for water supply only;
universal (for water and heating).

XLPE pipe structure

There are 4 types of polyethylene pipes (they all differ in cost and properties):

Crosslinking by electronic method is the irradiation of an already finished product. Referred to as RE-Xs.
Physical cross-linking is X-ray irradiation. According to the marking - this is RE-Xs. Such products are characterized by rigidity and permanent shape. Not resistant to extreme temperatures.
Cross-linking by chemical method (silane). According to the model - PE-Xb. This method is budgetary, and at the same time a product of good quality.
Cross-linking with hydrogen peroxide. It is considered the brand of the highest quality (PE-Xa). It is resistant to chemical action, to lowering and raising the degree to 110 ° C, to physical influences, and keeps its shape.

Features, advantages and disadvantages

The advantages of pipes made of cross-linked polyethylene include the following points:

Since pipes for heating made of cross-linked polyethylene perfectly tolerate high pressure and temperature, they have been used in the "warm floor" system, as well as in hot and cold water supply systems.
Very flexible.
Resistant to mechanical stress due to the aluminum layer.
Easy to install unlike copper or zinc pipes. Since you do not need to solder and install torches. Plus, ignition and fire simply cannot occur.
Eco-friendly and do not pollute the environment.
They are not afraid of corrosion due to their structure.
Inside the structure, layers will never form that interfere with the flow of water.
Light weight for easy transport and installation.

Rehau installation tool for XLPE pipes

The disadvantages include the following points:

Pipes for heating made of cross-linked polyethylene categorically do not tolerate ultraviolet rays. Under the sun, the material of the product begins to decompose and makes the water harmful to drink, fills it with toxins. The best solution there will be a coating of polyethylene tubes with varnish.
XLPE pipes for heating are very badly affected by nitric acid and other powerful oxidizing agents.

Each manufacturer of polyethylene pipes offers a proprietary tool for their installation.

Manufacturers of pipes for heating from cross-linked polyethylene.

The market leaders are such companies as REHAU, KAN-therm, UPONOR.

Consider the features of their products in more detail.

The company produces four types of polyethylene pipes under the RAUTITAN brand, namely Pink, His, Stabil, Flex.

Rehau XLPE pipes for heating have the following features: they are durable, easy to install, they have a single program of fittings for heating and water supply.

They are characterized by a compression sleeve connection technique without rubber sealing rings. They have low pressure losses at local resistances.

Rehau XLPE pipes for heating are the best price / quality ratio.

The advantages of RAUTITAN PX polymer fittings are to withstand long-term tensile loads, rust resistance, good impact strength.

Meet all hygiene standards.

The components of the system consist of pipes (diameters from 16 to 63 mm), fittings and compression sleeves and other accessories (fire collars, bracket program, fixing gutters, pipes for connecting heaters, etc.).

The KAN-therm Push system has a number of advantages. Firstly, it is operational durability (over 50 years!). Secondly, resistance to pipe contamination with boiler stone. Thirdly, insensitivity to hydraulic shocks, as well as high smoothness of the inner surface, microbiological and physiological neutrality in drinking water supply systems.

Pipe materials are environmentally friendly.

They are quick and easy to install and light in weight.

The PE-RT pipes of the KAN-therm Push system are produced (according to DIN 16833) from octane polyethylene copolymer (Dowlex). PE-Xc pipes Manufactured (according to DIN 16892) from high density polyethylene and subjected to a process of molecular crosslinking by electron flow.

All types have a protective layer that prevents the diffusion of oxygen into the coolant through the pipe wall.

May be milky or red.

Pipes (depending on what diameter) are supplied in coils of 200, 120, 50, 25 m in a carton, as well as on reels of 600, 700, 850 or 1100 m - they are used in case of laying underfloor heating.

Uponor heating XLPE pipes are made from cross-linked PEX-a polyethylene, which is obtained by cross-linking with hydrogen peroxide at high temperature and pressure.

The manufacturer gives a guarantee of quality and claims a service life of more than 50 years.

Mounting at temperatures down to -15°C - reducing the seasonal dependence of mounting.

Will not overgrow with lime and other deposits.

Diameter - from 16 mm to 110 mm.

They are well suited for concealed installation (in floor screed and wall strobes) and in underfloor heating systems.

Many people use polyethylene pipes for underfloor heating (“warm floor” system) and note the easy installation that can be done by hand.

Thus, PEX pipes for heating have their own advantages and disadvantages. They must be taken into account when choosing this heating system. They are easy to assemble and very reliable.

I am thinking about changing all the pipes in the house to cross-linked polyethylene (PEX).

I saw Rehau pipes, I can’t say anything bad. Advise which companies are better and more profitable to use XLPE heating pipes?

In the case of Rehau, for sure, as is often the case, you overpay for the brand. There must be an alternative that is as good as Rehau, but a little cheaper.

Of course, you can try another brand of polyethylene pipes, for example, SANEXT. They are produced here, in Russia, and are cheaper by about 30%. negative feedback little, a kind of budget analogue of Rehau. But at present, Rehau XLPE pipes for heating are the most reliable and convenient on the market. They are better than copper and metal-plastic, have fewer drawbacks. With PEX, it is convenient to carry out installation, because they bend well and are very durable.

XLPE pipes for heating - Rehau, Kan, Uponor

Pipes made of cross-linked polyethylene for heating are the reliability of your pipeline. Features, types, pros and cons of RE-X. Polyethylene pipes Rehau, Kan, Uponor

XLPE pipe is the best choice for heating

Polymer materials today are able to replace traditional metal and various alloys in many industries and construction. At the moment, the demand for the so-called low-temperature heating systems has increased, which fully cope with the heating of the entire room or its individual sections at a coolant temperature of no higher than 80 degrees. In order to significantly save on material for highways, instead of metal, cast iron or light alloy pipes, alternative material – cross-linked polyethylene.

A XLPE pipe for heating is considered the most suitable analogue due to many technical advantages, including ease of installation, high mechanical strength and low cost.

Main production methods

Polyethylene is a synthetic material with a high molecular weight structure. Through cross-linking, it gains additional strength and chemical resistance - the main properties that characterize the pipeline.

The crosslinking process itself in modern production conditions can take place in three main ways:

radiation beam. The flow of charged particles penetrates into the molecular structure of polyethylene and rearranges it, forming stronger and more stable bonds. The crosslinking ratio in this way is about 60%;
chemical method using organic silanides (silane method). Due to the action of chemically active reagents, a degree of strength of at least 65% is achieved;
peroxide method. The method also refers to the chemical variant, hydroperoxides act on polyethylene. It is considered the most effective (the cross-linking coefficient reaches 75%), but also the most expensive and technologically complex.

It does not matter how the final material was obtained, it all depends on the crosslinking coefficient. The higher the indicator, the more durable, chemically resistant the polyethylene pipe will be and can be used in a higher temperature range.

In parallel, with an increase in the index, the fragility of the material also increases, as well as decreases its flexibility and ductility. With the maximum value of the coefficient closer to 100%, the cross-linked polyethylene pipe will resemble glass in its physical properties. It is for this reason that the degree of crosslinking from 65 to 70% is considered the optimal value.

Basic properties

The pipeline made of cross-linked polyethylene, regardless of the method of production, has unique technical properties:

high wear resistance and durability. One of the most important indicators for pipes. Subject to the installation conditions, such a line will serve at least 50 years;
low degree of thermal conductivity. This characteristic is also important - the coolant reaches the desired section of the heating system with virtually no loss;
increased coefficient of resistance to temperature fluctuations and water hammer;
high degree of hygiene. This property makes it possible to use a XLPE pipe not only for technical highways, but also for domestic use.

In addition, with a temporary impact on the pipe of deforming forces, the product returns to its original state, if the threshold of irreversible (critical) deformation has not been passed.

One of the most significant design features is three-layer product- between two layers of cross-linked polyethylene, an additional strong aluminum foil is placed, which is both a reinforcing layer and a heat insulator.

Areas of use

Due to its excellent technological properties, XLPE pipes are widely used in various industries. First of all, these are various pipelines for domestic use. XLPE pipe for underfloor heating is the best option due to high reliability, low heat loss coefficient and long service life.

Products are also actively used for low-temperature radiator heating systems in multi-apartment and private houses. Additional applications include snow melting or de-icing systems in open areas.

Installation of the pipeline, regardless of the purpose, is carried out in a hidden way- under a concrete screed (warm floor), behind false wall panels. Quite popular is the method of laying highways in strobes, followed by grouting or plastering. With proper installation, such a line can serve for decades, since with a completely closed structure, the probability of mechanical damage is reduced to zero.

Cross-linked polyethylene pipes are the most reliable option for creating various household main communications. The only feature of these products is not very low cost, which is due to the laborious and costly process of crosslinking and the use quality materials. The money spent will be repaid by the reliable service of such a pipeline for at least 50 years.

Today, there are a large number of unscrupulous sellers and some manufacturers (mainly from China) who pass off cheaper plastic pipes as cross-linked polyethylene pipes. The most well-known companies producing high-quality products are the German manufacturers REHAU and TECE, the Italian brands VALTEK and UNIDELTA, and inexpensive pipes from the Polish manufacturer KAN.

XLPE pipe for heating

Cross-linked polyethylene pipe for heating - main varieties, cross-linking methods, key features and technical data, various fields of application

7 tips on which XLPE pipes for underfloor heating, heating and water supply are better to choose

Flexibility, strength, durability, the ability to restore shape after damage are the main, but far from the only, advantages of XLPE pipes. They confidently displace other types of pipes from the market, are actively used in the installation of underfloor heating, plumbing (hot and cold) and heating systems. Are they really that versatile? Let's dot all the "i" and try to figure out which cross-linked polyethylene pipes for underfloor heating, heating and water supply are better to choose, what to look for when buying and which manufacturers you can trust.

No. 1. Production features

When treated in a special way with ordinary polyethylene (a polymer composed of carbon and hydrogen atoms), some of the hydrogen atoms are separated, leading to the formation of a new bond between carbon molecules. The process of obtaining these additional carbon bonds is called stitching. affect polyethylene. various substances and methods, so the degree of crosslinking may vary. The optimal indicator is 65-85%.

Cross-linking improves the properties of polyethylene: increased resistance to high temperatures, improves flexibility, wear resistance, it becomes possible to self-heal after mechanical stress. The crosslinking process was developed in 1968 by the Swedish chemist T. Engel, but he underestimated his invention, considering it uncompetitive. The patent was bought from him by the WIRSBO company, which was the first in the world to start industrial production pipes of cross-linked polyethylene (PEX) and is still a leader in this area. Such products did not immediately hit the domestic market, but now they are very popular.

PEX pipe usually consists of three layers: inside - cross-linked polyethylene, outside - an oxygen-protective layer, they are connected with glue. On sale there are 5-layer pipes. They also have a layer of glue and cross-linked polyethylene on top of the oxygen-protective layer.

No. 2. PEX pipe stitching method

The most important parameter when choosing XLPE pipes is the method of crosslinking used by the manufacturer. It determines the number of formed additional bonds, and consequently, the performance of the product.

For the formation of additional bonds (bridges) in polyethylene, the following cross-linking methods are used:

cross-linking with peroxide, such pipes are marked PEX-A;
silane crosslinking, PEX-B;
radiation crosslinking, PEX-C;
nitrogen crosslink, PEX-D.

Pipes PEX-A obtained by heating raw materials with the addition of peroxides. The crosslink density of this method is maximum and reaches 70-75%. This allows us to talk about benefits, as excellent flexibility (maximum among analogues) and memory effect (when unwinding the coil, the pipe almost immediately takes its original straight shape). Bends and creases that may appear during the installation process can be corrected by slightly heating the pipe with a building hair dryer. Basic minus- this is a high price, since the technology of peroxide crosslinking is considered the most expensive. In addition, during operation, washout chemical substances, and somewhat more intense than in other PEX pipes.

Pipes PEX-B produced in two stages. First, organic silanides are added to the feedstock, resulting in an unfinished pipe. After that, the product is hydrated, and as a result the crosslink density reaches 65%. Such pipes are characterized by a low price, they are resistant to oxidation, have high pressure indicators at which the pipe breaks. In terms of reliability, they are practically not inferior to PEX-A pipes: although the percentage of crosslinking is lower here, the bond strength is higher than with peroxide crosslinking. From cons note the rigidity, so it will be problematic to bend them. In addition, there is no memory effect here, so the original shape of the pipe will not be restored well. When creases appear, only couplings will help.

Pipes PEX-C are obtained with the so-called. radiation crosslinking: polyethylene is exposed to electrons or gamma rays. The production process requires careful control, because the uniformity of crosslinking depends on the location of the electrode relative to the pipe. The degree of crosslinking reaches 60%, such pipes have a good molecular memory, they are more flexible than PEX-B, but cracks can form on them during operation. Creases are corrected only by couplings. In Russia, such pipes are not widely used.

Pipes PEX-D produced by treating polyethylene with nitrogen compounds. The degree of crosslinking is low, about 60% Therefore, in terms of performance, such products are significantly inferior to analogues. The technology has actually become a thing of the past and is hardly used today.

On sale you can find PEX-EVOH pipes. They differ not in the way of crosslinking, but in the presence of an external additional anti-diffusion layer made of polyvinylethylene, which further protects the product from oxygen entering the pipe. According to the method of stitching, they can be any.

Pipes are considered to be of the highest quality. PEX-A, but they high price forces many to use PEX-B pipes. These two types of products are the most widely used on the market, and the choice between them depends on the budget, personal preferences and the characteristics of the pipeline that needs to be built with their help.

Do not confuse XLPE pipes with:

No. 3. Advantages and disadvantages of PEX pipes

Calling XLPE pipes a unique and revolutionary product is difficult, but The advantages of the material, indeed, are many:

Cross-linked polyethylene pipes are, of course, more expensive than cast-iron or ordinary polyethylene pipes, but they are still quite affordable, however, you will also have to spend money on the corresponding fittings. Installation is carried out using a special hand tool. In this case, it is very, very important not to damage the protective layer. We can say that the durability of the pipeline will depend on the care during work, which is why it makes sense to entrust the installation to certified craftsmen.

No. 4. Scope of use

The performance characteristics of pipes made of cross-linked polyethylene allow them to be used for construction of the following engineering networks:

cold and hot water supply;
heating system;
water heated floor.

For industrial purposes, PEX pipes are not used - large-diameter material (for example, for main water supply) is expensive.

No. 5. Cross-linked polyethylene or metal-plastic?

XLPE pipes and metal-plastic pipes are the main competitors when it comes to arranging plumbing, heating systems or underfloor heating. They have a lot in common. Both types of pipes are quite flexible, durable, resistant to corrosion and relatively easy to install - you certainly won’t have to weld anything. True, metal-plastic pipes are still easier to install than PEX pipes, with which you need to be extremely careful.

At the metal plastic pipes slightly higher thermal conductivity (0.45 versus 0.38), but they will not survive freezing inside the coolant. PEX pipes, after the water in the system has melted, can be operated as before. Moreover, some types of PEX pipes easily restore their shape. Resistance to high temperatures and pressure is high for both types of pipes: metal-plastic can withstand pressure up to 25 atm at a temperature of 250C, can be operated at coolant temperatures up to + 950C with a short-term increase to + 1200C, however, the maximum pressure is 10 atm. Thus, the performance characteristics are quite comparable with those of the XLPE pipes that we cited above.

The choice depends mainly on the features of the operation of the water supply system and the budget. The spread of prices among pipes, even within the same group, is significant, but PEX pipes often turn out to be cheaper than metal-plastic ones.

No. 5. Diameter and length

Cross-linked polyethylene pipes are sold in coils of 50, 100 and 200 m. Pipes with a diameter of 40 mm or more are sold in segments up to 12 m. On a pipe along its entire length information must be provided on material of manufacture (type of stitching), operating temperature, pressure, diameter, date and place of manufacture. For added convenience, some manufacturers put risks on the product exactly every meter.

The choice of pipe diameter depends on the type of pipeline, the water pressure in it, the number of consumers and other parameters. General recommendations for the selection of diameter are as follows:

pipes with a diameter of up to 15 mm (10.1 * 1.1, 14 * 1.5 and others) are suitable for supplying water from the main water pipe to cranes;
pipes 16 * 2 are used for organizing underfloor heating, 16 * 2.2 are suitable for hot water supply and radiator heating. Pipes with a diameter of 16-20 mm can be used as the main pipe for cold and hot water supply of apartments and small private houses;
pipes 20-32 mm are suitable for organizing water supply in cottages, they are also used for heating, pipes with a diameter of more than 20 mm are usually not used for underfloor heating;
pipes 40-50 mm are suitable for a riser in apartment buildings;
pipes with a diameter of 50-63 mm are used both in heating and water supply systems.

Usually, the manufacturer indicates for what purposes this or that pipe is best suited, for example, for heating, hot water supply, or whether it is universal in use.

Calculate length not difficult, but for this there must be an exact plan for the plumbing system, radiator or underfloor heating. We measure the length of the proposed pipeline and multiply the resulting value by 1.2 - this is a margin for unforeseen situations that may occur during installation.

No. 6. XLPE Pipe Fittings

Looking ahead, we note that it is better to take fittings from the same manufacturer as pipes. Even with the same declared dimensions, the difference in the diameter of products from different manufacturers can reach 0.5 mm. In this case, it is difficult to talk about the absolute tightness and reliability of the system.

For joining individual segments PEX pipes use these types of fittings:

It is impossible to weld, solder and glue the seams of pipes made of cross-linked polyethylene.

No. 7. XLPE Pipe Manufacturers

To be 100% sure that the pipeline will not have to be repaired in a couple of years, or even changed at all, it is better to take pipes from a trusted manufacturer that gives a guarantee for all products. Large companies will not risk their reputation and produce low-quality products. So, today on the market of pipes made of cross-linked polyethylene there are such major manufacturers:

Most manufacturers indicate exorbitant warranty periods, which are 20-30 years, and somewhere even all 50. The terms of this warranty must be carefully studied so that they are not violated during installation and operation, otherwise the manufacturer will have the right not to fulfill its obligations.

7 tips on which XLPE pipes for underfloor heating, heating and water supply are better to choose

Cross-linked polyethylene - innovative material for the manufacture of pipes. Unlike ordinary PE, it withstands high pressure, the action of chemicals, hot water.

It is applied to pipelines of cold and hot water supply, heating.

Installation of PEX pipes is not difficult, but has features, knowledge of which will help to perform the installation correctly.

Pipes for heating and water supply systems made of cross-linked polyethylene

The new material is showing properties of metals and polymers. Cross-linked polyethylene is a thermoplastic polymer with a three-dimensional structure.

Cross-linking technology creates intermolecular network, similar to the crystal lattice of substances in the solid state.

Due to this, flexibility is maintained, the melting point increases, resistance to thermal deformation, scratches, cracks. The material is designated PEX (PEX), where X means stitching.

Application in residential buildings

Cross-linked polyethylene is used for laying pipelines external and internal engineering systems residential buildings: heating, sewerage, hot, cold water supply.

Preferred areas of application:

Warm floor.
Heating systems working with coolants at low temperatures.
Internal water supply.

Photo 1. Installation of warm water floors with red cross-linked polyethylene pipes indoors.

Heating with horizontal wiring.
Gutters.

Important! Molecularly modified polyethylene is environmentally friendly and safe: it does not emit toxic substances, so it is used for living quarters. When burning, it decomposes into compounds harmless to humans: carbon dioxide and water.

Technical properties

Burning temperature - 400°C
Melting - start at 200°C.
Average density - 940 kg/m3.
Stretching without breaking - in the range 350-800%.
Preservation of characteristics at temperature down to -50°C.
Thermal conductivity - 0.38 W/mK.
Flexibility.

When operating under standard conditions (coolant temperature within 75°C) cross-linked polyethylene will serve about 50 years old. With constant use with extreme loads: increased pressure, 95 degree coolant service life will be reduced to 15 years.

Dimensions and diameter

PEX pipes are produced with a diameter 10-280 mm and wall thickness 1.7-29.0mm. Supplied in rolls in lengths 6, 8, 10, 12 meters.

According to the degree of pressure resistance, XLPE pipes are divided into the following types:

light: 0.25 MPa (2.5 atm);
medium light: 0.4 MPa (4 Atm);
medium: 0.6 MPa (6 Atm);
heavy: 1 MPa (10 Atm).

The above pressure is conditional, the data is valid when pumping water t 20°C.

Advantages and disadvantages

Molecularly crosslinked polyethylene retains positive traits standard PE and gains new benefits:

The disadvantages of pipes made of cross-linked PE include sensitivity to UV radiation and slow destruction under the action of free oxygen penetrating into the structure from the air.

Attention! To prevent unwanted contact of PEX pipes with air, it is used anti-diffusion protection. Such a coating should be handled carefully so as not to scratch it during installation, transportation. Products protect against ultraviolet radiation special additives, which are included in the composition at the production stage.

Types of PEXAU pipes

Universal- equally suitable for use in different areas: for arranging a water floor, hot and cold water supply systems, autonomous, central heating.

Photo 2. Universal pipe made of Rehau Pautitan flex polyethylene, suitable for any type of heating.

Specialized- have a narrow scope. They are intended for a certain type of pipelines, for example, only for cold water supply or individual heating.

Depending on the conditions of use, water or non-freezing liquids - antifreezes are used in heating pipes made of cross-linked polyethylene.

In standard mode, heating pipes operate at the limit temperature up to 95°C and pressure up to 10 atm. In an emergency, they withstand temperature fluctuations up to 110°C with a double increase in pressure.

Varieties of pipes from the leading manufacturer Uponor

Uponor (Finland) produces pipes four types:

Aqua Pipe- for hot and cold water supply.
Comfort Pipe Plus, Radi Pipe- for floor radiator heating, cooling systems.
Combi Pipe- universal.
Comfort Pipe- for floor heating systems.

Photo 3. Pipes made of cross-linked polyethylene Uponor Comfort Pipe, designed for underfloor heating.

Size range of products made of cross-linked polyethylene 15-110 mm. Supplied in coils 50-540 meters, 6 meter pieces.

The German company REHAU produces a large assortment of pipes of the series RAUTITAN:

FLEX- differ in flexibility, are applied to cold, hot water supply, floor, radiator heating of premises.
STABIL- universal, have an internal aluminum layer.
HIS- universal use in temperature regime up to 70° C up to 10 atm.
PINK- for underfloor heating, radiator wiring in residential and public buildings.

Connection - compression sleeve fittings, size range 12-250 mm. Pipes are supplied in straight lengths 6 m or in bays 25-125 meters.

Installation

There are three ways to connect PEX elements:

Compression fittings- suitable for water supply (cold and hot). If necessary, the plumbing is disassembled at any time.
Press fittings- a non-detachable connection is obtained. The method is based on the ability of cross-linked polyethylene to recreate the shape.
Electrofusion fittings- the strongest and most reliable connection. The method requires skills when working with welding equipment.

Attention! When choosing a mounting method, consider the pressure that will be in the system. Compression fittings withstand up to 2.5 atm, press fittings - up to 6 atm, electrowelded - give a monolithic connection.

Tools

Depending on the chosen installation method, you will need:

Electrofusion Couplings- type of fitting in the form of a sleeve with built-in heating terminals.

Reference! Fittings - connecting elements of the pipeline, used for assembly and docking, branching, pipe turns. Main material: brass, but polyethylene, polyvinyl chloride, polypropylene, combined parts are produced.

Preparatory work

Before starting installation, ensure that the workplace is clean - at the joints dust and dirt must not penetrate.

Guided by the wiring diagram for connecting the radiator, prepare required number of fittings and pipes. Cross-linked polyethylene is plastic, so fix the pipes to the wall on the brackets.

Check manifold outlets- They must be in good condition. To avoid the formation of condensate on the "cold" system and the heat loss of pipes with hot water, prepare additional thermal insulation.

Rules of operation and connection to the radiator

A high-quality cut is the key to the tightness of the joint. cut the pipe strictly at 90°- perpendicular to the horizontal axis.
Make sure the cutting surface is completely flat.- without cuts, roughness, waves.
For connections, choose only specialized fittings- for cross-linked polyethylene.
If a pipe bend is needed, first warm the bent area with a building hair dryer.
When using the electrofusion method monitor the temperature of the device. Cross-linked polyethylene can overheat and burn.
For quality installation follow the pipe and fitting manufacturer's instructions.

In cases where the question arises of laying or replacing heating pipes, it is first necessary to decide which pipes of all existing species will be selected for this. A few years ago there was not much choice, since the only heating pipes were steel.

But their shortcomings, such as susceptibility to corrosion and short service life, practically forced specialists to develop completely different, more stable types of pipes.

Recently, they have been actively used. But among the variety of plastic pipes, polyethylene pipes for heating are the best. Their advantage lies in their durability, since on average they can last about 50 years.

They are also very smooth inside, so various deposits do not form on them, and due to the fact that the lumen of the pipe does not narrow, then, as a result, the throughput of such pipes does not decrease.

Also, polyethylene pipes for heating are also good because they are made of environmentally friendly material, which is completely safe for use in residential buildings.

Polyethylene pipes are lightweight, which greatly facilitates their transportation of parts of the heating system and, of course, themselves installation work.

Heating system made of polyethylene pipes

By itself, the installation of such pipes is not very complicated and, unlike, does not require any welding, unlike similar steel pipes. The result is reliable system heating with good tightness.

And if you need to repair the damaged section of the heating system, which consists of polypropylene pipes, then such replacement work is not very difficult.

Installation of a heating system from polyethylene pipes in a house

Such cross-linked polyethylene pipes for heating which has become almost the latest technological innovation, have a high density and increased impact strength.

Therefore, they are widely used for heating systems.

In some cases, you can install the heating system with your own hands, adhering to the following phased work:

Heating installation begins directly with the creation of a home heating scheme. Each building assumes some preferences in the heating system.
Therefore, initially it is necessary to decide which type of heating is preferable: underfloor heating, radiator heating or a heating system consisting of these two types. Basically, this is how modern houses are designed.
The next step is to calculate the heat load. Basically, such calculations are only indicative, which are based on the modern framework of various heat losses, since cross-linked polyethylene for pipe heating also has them.
After the necessary calculation has been made, they begin to choose a heating boiler. The main thing is not to forget about the direct preparation of hot water. In that case when hot water be prepared in the boiler of the building, then you can completely neglect such a boiler for heating.
If the water will be heated directly with the help of a high-speed heat exchanger, then when choosing the maximum power of the boiler, it is necessary to take into account its maximum water intake.

In order to select the required radiator, you will first have to decide on the type of wiring for the radiator heating itself.

Only two types of wiring are suitable for do-it-yourself installation: collector (beam) and two-pipe.
Both systems have good controllability. But, despite this, in the radiator heating of the collector system, the possibility of making a mistake during installation work is much lower.
Pipes for heating, cross-linked polyethylene, which is a reliable material, also require good wiring to them. So collector wiring has its own difference from other types in that it individually connects the radiator to the collector.
Although such a system will require more XLPE pipes for heating, this is still compensated during installation work by the absence of various additional connections. And in this case, you will only need to tighten the nuts at the collector and radiator.

A two-pipe heating system is mounted using special pipes, which can also be used for heating a polyethylene pipe. In this system, the connection of its parts occurs by welding them with a special tool.

After the choice is made and the boiler and the necessary heating devices are purchased, they place them directly in their places.
Next, the installation of radiators is carried out precisely from installing them in their places. It is necessary to place radiators exactly under window openings. Their arrangement will create an air flow, which will subsequently prevent condensation from appearing on the windows.
When installing radiators, you need to be aware that a distance of 150 millimeters must be left between them and the floor, and this distance must be at least 100 millimeters between the radiator and the window sill. Other distances must be determined locally and taking into account the selected heating appliances.

When choosing a collector wiring for radiator heating, radiators with a lower connection are used, since such a lower connection node simply cannot be installed incorrectly. In this case, a polyethylene pipe for heating will also greatly facilitate the installation of the heating system.

The next stage of work is the installation of the boiler itself. To begin with, it is worth saying that it is mandatory to have a complete scheme of the heating system in order to have an idea of \u200b\u200bhow it should work in this case.
If there is no final understanding of the operation of the entire system, it is better to consult a specialist. A polyethylene pipe for heating also requires proper handling, which you also need to know in advance so that the finished heating system works well.

Also, a boiler room scheme can be developed using the help of professionals or relying only on one's own strength. Its simplest version uses wall-mounted double-circuit gas boilers.

Features of polyethylene pipes

When installing it with your own hands, it is best to use polyethylene pipes - pipes for heating. Large with the existing low cost of fittings for them, even with this small object in the form of a personal boiler room for the house, it will pay for all the specialized tools purchased to carry out the necessary installation work.

PEX pipes made of cross-linked polyethylene for heating with hoists have been used relatively recently and immediately gained recognition from many experts.

This material is obtained by cross-linking polyethylene and therefore has good density and impact strength.

Such cross-linked polyethylene has the following advantages:

sufficiently resistant to any corrosion;
absolutely not prone to overgrowth on inside your pipe;
has a fairly low sound conductivity;
has excellent tightness;
this material is durable;
it is environmentally friendly;
completely hygienic;
it can be used for hidden installation.

The good quality of such pipes is the minimum presence of connections during their installation, but at the same time they differ from their counterparts in a fairly high reliability. Also pipes made of cross-linked polyethylene can withstand an unlimited amount of frozen water.

And due to the fact that these pipes are connected using the axial technique, the installation process itself is completely independent of the human factor. The disadvantage of such pipes is the high price, especially for pipes over 40 millimeters in diameter.

Thus, at present, it is not difficult to choose any material of your choice, or to independently install the heating system. The main thing is to foresee all the points of such installation in advance, including drawing up a complete diagram of the future heating system.

In some cases, it will not be superfluous to get advice directly from experts in this field.

High-quality heating of a house or apartment is a guarantee of comfort and coziness of living. And it depends not least on the quality of the created heating system. Today, for these purposes, manufacturers offer a variety of various materials, greatly simplifying the installation work and increasing the durability of the systems being created.

It is clear that none of the water heating systems can do without a fairly large number of pipes, and their choice should be approached with the utmost responsibility. Gone are the days when steel pipes VGP were practically no alternative. Modern Choice rich. For example, XLPE pipes for heating are relatively new material which has many advantages over others. However, it also has its own characteristics that should be taken into account. In order not to make mistakes when considering the question of what are suitable, during the installation work and further - already during the operation of the heating system, it is necessary to have an idea about the main characteristics and capabilities of this material.

What is cross-linked polyethylene?

You should not think that ordinary polyethylene, familiar to everyone, sold in the form, for example, of films of various densities, is the same material from which they are made for plumbing and heating circuits. For products that will experience considerable operational loads, it is cross-linked polyethylene that is used. And the key word in the title is still "stitched". Yes, the basis is the same, and the differences lie in the features of the molecular structure.

We will try to explain the difference intelligibly.

Conventional polyethylene has a linear molecular structure. Long chains of linear molecules are not interconnected. Therefore, the material does not differ in high resistance - it is easy to tear it apart by mechanical action, and even with not very large heating, it begins to “float”.

Chemical technologists tried to change the molecular structure of the material somewhat, namely, to try to connect linear molecules with cross-links.

During the manufacture of this material, the molecular chains are “crosslinked”, which creates numerous stable cross-links. In fact, the linear structure turns into a three-dimensional one. It is important that the material not only does not lose all its positive characteristics, but also acquires much greater stability. The more intermolecular bonds created, the higher the degree of crosslinking is considered.

One of the very interesting and useful properties, acquired by polyethylene as a result of cross-linking, is a kind of "memory" of the original shape of the product from this polymer. So, with an increase in pressure, with mechanical or thermal effects on the same pipe, its deformation is quite possible. However, after the loads are normalized, removed or weakened, the material tends to restore the previously given original shape. Agree that this is a very important advantage for the heating system.

Polyethylene pipePE-RT

An innovative development in the production of pipes has become products made of PE-RT polyethylene (polyethylene with increased heat resistance - "Polyethylene of Raised Temperature resistance"). By and large, this type of polyethylene cannot be fully called a crosslinking product. The fact is that already the initial granular raw material from which products are made has stable intermolecular bonds, and even more branched than those of PEX.

The process of creating PE-RT became possible with the development of technology that allows you to control the processes of spatial formation of macromolecules. These developments allow you to create materials whose structure will correspond to precisely specified parameters. This opens up opportunities to focus on a certain property of materials.

The abundance of intermolecular bonds makes the material resistant to internal and external loads, eliminates the appearance of cracks or breaks during strong bends. Despite aggressive influences, PE-RT, unlike PEX, always retains its thermoplasticity. Therefore, the connection of pipes of this type can be made not only with the help of pressure fittings, but also using welding technology. This simplifies and reduces the cost of installation, and high-quality welding ensures the highest reliability of the joints, and hence the heating system as a whole.

Given the advantages of PE-RT, we can conclude that it is confidently replacing the previously widely used PEX products from the market. These advantages include the following qualities:

The manufacturing technology of PE-RT is much simpler, since it does not require an intermolecular crosslinking cycle. All the necessary properties to achieve the required parameters are already incorporated in the raw semi-finished product. Interestingly, heat-resistant polyethylene waste can be recycled without losing any of the original qualities of the product.
The durability of PE-RT pipes is estimated at 50 years or more.
This type of pipe, due to its plasticity and strength, is able to withstand several freezing cycles together with the coolant, without losing its original qualities and depressurizing the heating system.
PE-RT pipes are repairable, which is impossible for PEX-analogues.
Due to its structure, the material perfectly absorbs the sound of the coolant flowing through them. In addition, due to their plasticity, they do not emit squeaks in the system, which is sometimes the case with PEX pipes.

PE-RT is used both for the production of metal-plastic pipes and those made only from this polymer.

Both the metal-plastic version and PE-RT-polyethylene pipes have higher technical and operational characteristics than their PEX counterparts.

Many PE-RT pipes, if they do not have an aluminum layer, are equipped with special oxygen barriers. As this layer, manufacturers use their own developments, such as EVON or OXYDEX.

As an example, we can give a table with the main technical and operational characteristics of PERT-AL-PERT pipes of a fairly popular COMPIPE production brand:

Name of parameters	Indicators
Outer diameter, mm	16	20	26	32
Wall thickness, mm	2	2	3	3
Coil length, m	200	100	50	50
Pipe weight (g/rm)	113	149	264	331
Pipe cavity volume (l/rm)	0.113	0.201	0.314	0.531
Minimum bending radius, mm	45	60	95	125
Outer layer (material)	PE-RT (high temperature resistant polyethylene)
Inner layer (material)	PE-RT(high temperature resistant polyethylene)
Connection method of aluminum layer	TIG butt welding
Working temperature, ˚С	70
Maximum temperature, ˚С	95
Maximum pressure, bar	10
Linear expansion coefficient, (K⁻¹)	2.3×10⁻⁵

Prices for PE-RT pipes

PE-RT pipes

Methods for connecting polyethylene and metal-plastic pipes

To connect pipes made of cross-linked polyethylene, special fittings are used, and the installation itself is carried out using a compression method (crimping) or using diffuse welding technology. Fittings can be polymer or metal (brass or bronze). Polymer fittings are well combined with pipes made entirely of polyethylene PEX or PE-RT.

Such connections have already proven their high reliability, therefore they are quite suitable for the operating conditions of heating systems. Of course, it is necessary to choose pipes and fittings from the same manufacturer, since only such a combination will guarantee the quality of the installation.

You may be interested in information about what they are

So, there are several ways to connect.

One of the simplest and quick ways mounting is the variant with compression sleeve. The whole process consists of three steps:

1 - A crimp sleeve is put on the pipe and shifted from the edge by about 100 mm. Then, the pipe cavity at the edge is slightly flared with a special expander. This is necessary so that the fitting can easily enter into it.

2 - Next, a fitting is inserted into the expanded channel of the pipe until it stops. Since the cross-linked polyethylene will tend to return to its original shape after the expansion process, it will tightly press against the material of the connecting part.

3 - At the final stage, the sleeve put on earlier is shifted, closing the created connection. Thus, the polyethylene will be tightly clamped between the fitting and the sleeve. The shift of the sleeve requires considerable effort, therefore it is done with a special tool.

Another option, already mentioned above, is suitable for connections both for pipes made only from polyethylene and for metal-plastic ones. This method includes approximately the same stages of work, but at the end of the process, the sleeve shifted to the edge of the pipe is crimped with special tongs.

You might be interested in knowing what is

PERT-AL-PERT pipes can be connected using a fitting and a compression nut:

On metal pipe the cap nut is put on first, then the compression ring.
Then, after a slight flaring of the edge, a metal fitting is inserted into the pipe until it stops, which often has sealing rubber rings, but may be without them.
The next step is to move the compression ring to the edge of the pipe, and the nut on top of it.
The nut is tightly screwed onto the thread of the fitting.

This connection method does not require special tools - it is enough to have a wrench or adjustable wrench on hand. However, according to experts, such pipe fittings are not highly reliable. Leakage may occur immediately after starting the heating circuit or after a short period of time. In any case, it is not recommended to leave such joints without visual control.

Another installation method is diffusion welding, which can only be used to join pipes based on PERT. Of course, special fittings must be available for such installation.

Complicating this work is the need for a special welding machine. If it is possible to rent such a device, it is quite possible to install the system yourself. In general, the process is very similar to welding polypropylene pipes and is usually very quickly mastered even by beginners.

You may be interested in information on how to mount

Advantages and disadvantages of XLPE pipes

To summarize the above, it makes sense to highlight the advantages and disadvantages of PEX and PE-RT polyethylene pipes.

So to benefits pipes made of cross-linked polyethylene when used in heating systems include the following factors:

Resistance to high temperatures, and this is especially pronounced for PE-RT pipes.

Excellent strength characteristics - the pipes are resistant to external mechanical influences and internal pressure loads.
The elasticity of the material allows the use of pipes in complex schemes laying with many turns under a small radius.
Even after serious deformations, the pipe tends to restore its shape.
Inertness to corrosion, as well as aggressive components of the coolant.
The ideal smoothness of the inner walls does not create significant hydraulic resistance to the coolant circulating through the pipes. In addition, the possibility of insoluble deposits on the inner walls is almost completely eliminated, even if a low-quality coolant is used.
The low weight of the pipes and the large length in coils speed up and simplify installation work for laying long circuits.
High reliability of connections.
The environmental friendliness of the material allows them to be used for installation in the plumbing system, the water from which is used for drinking and cooking.
Pipes in open areas do not require periodic painting - they are quite "pretty" in themselves.

However, in order to fully have an idea about pipes made of this material, it is necessary to single out their flaws , since they also exist:

Both PEX and PE-RT pipes have a relatively low resistance to ultraviolet radiation. Therefore, they are best used in closed areas (the same contours of the "warm floor" or wiring hidden in the walls).
The cost of quality pipes complete with the necessary press fittings can be quite impressive! In addition, one cannot discount the need for a special installation tool, and the skills to work with it.
Very great care should be taken when using pipes made of cross-linked polyethylene in a heating system connected to a central one. In any case, it is better to check the permissible operating parameters several times and compare them with the possible operating modes of the system, about which information must be obtained from local utilities in advance.

You may be interested in information about what is in the heating system

A few words about brands and prices

The issue of the cost of purchased pipes is always important. But it should not be decided solely from the standpoint of maximum cost savings, to the detriment of quality. Therefore, we can advise the main thing - to choose materials from truly reputable manufacturers in order to “bite your elbows” due to problems that began even during installation or, worse, already during the operation of the system.

Pipes manufactured by well-known European companies have earned a good reputation. These include Rehau, Henco, Uponor, Kermi, Oventrop and others. Some domestic firms are also trying to keep up with them, but so far the priority for professionals is still imported products.

The table below shows several pipe options that are well suited for arranging a "warm floor" system. Price indicators are averaged, and in different regions may differ from those shown - this is easy to check on the spot.

Manufacturer and pipe model	Brief specifications	Length in the bay	Price per linear meter
Uponor PEXa evalPEX Q&E 16 x 2.0	Diameter 16 mm. Cross-linked polyethylene PE-Xa, wall 2 mm, t max - up to 95 degrees, (short-term heating up to 110)	50 - 240 m	130 rub.
Uponor PEXa evalPEX Q&E 20 x 2.0,	Diameter 20 mm. Cross-linked polyethylene PE-Xa, wall 2 mm, t max - up to 95 degrees, (short-term heating up to 110)	50 - 120 m	150 rub.
REHAU "Rautitan stabil"	Diameter 16 mm. Metal-layer, PE-Xc/AI/PE wall 2.6 mm	100 m	175 rub.
REHAU "Rautitan stabil"	Diameter 20 mm	100 m	200 rub.
REHAU "Rautitan flex"	Diameter 16 mm. Cross-linked polyethylene RAU-PE-Xa, wall 2.2 mm	100 m	190 rub.
REHAU Rautitan Pink	Diameter 16 mm. Cross-linked polyethylene RAU-PE-Xa, wall 2.2 mm, t max - up to 90 degrees	120 m	150 rub.
Contour PERT D 16 red	Diameter 16 mm. Monolayer pipe PERT Russian production., t max - up to 90 degrees, pressure - up to 6 bar.	200 m	55 rubles
BioPipe PERT 16x2.0	Diameter 16 mm.	240 m	50 rubles
Thermotech MultiPipe PE-RT II, 16*2 mm	Diameter 16 mm. Five-layer PERT pipe with diffuse barrier	240 m	150 rub.

In the presented selection, pipes of the lowest price category are deliberately not shown, as well as products of dubious or not at all well-known manufacturers. The reasons are probably understandable - the author simply does not have the moral right to recommend such material for the installation of a heating system, which is created with the expectation of several decades of operation.

3.3

Is a polyethylene pipe suitable for heating? We will get acquainted with a relatively little-known material - cross-linked polyethylene, analyze its features and the installation methods used.

But first, some general information.

About polyethylene

What do we know about this material? Well, it's transparent... and they seem to make bags out of it. This is where the list of well-known information seems to end.

Let's try to expand it.

Polyethylene has been around for over a century. It was first discovered by accident by engineer Hans von Pechmann in 1899 and was immediately forgotten.
In 1933, the material received a second life in the form of insulation for telephone cable.
The material is a dielectric, elastic (moreover, it retains elasticity even at temperatures below zero) and is very chemically resistant. Concentrated sulfuric acid can be stored in a plastic jar indefinitely.
Polyethylene does not absorb water and does not let it through, representing a reliable waterproofing.
Tensile strength is high enough in order to make pressure pipes of cold water supply from polyethylene.

Healthy: physical properties polyethylene, including density and strength, vary depending on the polymerization conditions.
Moreover, the lower the pressure during the reaction, the stronger the resulting material. There are polyethylene of low, medium and high density.

All types of polyethylene soften at 80-120C. Given that the pipe will be under pressure in the water supply, manufacturers limit the operating mode of polyethylene pipes to a maximum temperature of ... 40 degrees.

Hence the unambiguous and final verdict: polyethylene pipes are not suitable for heating. Dot.

Useful modification

In its normal state, polyethylene consists of long monomolecular chains. However, there are a number of operations that can change its structure.

Due to heating in the presence of a catalyst, bombardment with electron beams, or simple immersion in water with a catalyst and special additives, the molecules begin to form not only longitudinal, but also transverse connections. Stitch together. The result is a fundamentally different material, which is commonly called cross-linked polyethylene (PE-S, or PE-X).

To understand how its properties have changed, we will give a description of a cross-linked polyethylene pipe for heating, manufactured in Germany under the Gabo Systemtechnik brand.

The pipe is able to work for the declared 50 years in the 90C / 7 bar or 70C / 11 bar mode.
The maximum operating temperature for it is 95C - the same as manufacturers usually indicate for reinforced polypropylene.
The pipe remains extremely flexible. The minimum bending radius is only 6 of its diameters. On the practical side, this means that by installing your own heating from cross-linked polyethylene, you can get by with a minimum number of relatively expensive fittings.

Thus, cross-linked polyethylene is suitable for heating systems without any reservations: according to the current SNiP, the temperature (see) in the internal engineering networks of residential buildings should not exceed the very 95C that the pipe, as we just found out, can withstand perfectly.

Production

Technology

As an example of production technology, let's take information from the website of the dealer of those same Gabo pipes.

The Germans are traditionally famous for their pedantry and in terms of compliance with technological standards, they are certainly ahead of the rest.

High-density polyethylene in the form of granules is melted and forced through the annular hole of the extruder - a special press that forms a pipe of the desired section.
During the extrusion process, continuous monitoring of the homogeneity of the material is carried out.
The pipe, intended for underfloor heating, acquires an oxygen barrier - the pipe is covered with a film of quick-drying ethylene vinyl alcohol.

Useful: all pipes for transportation drinking water even during the extrusion process, it is mixed with additives that make it opaque, including for ultraviolet radiation.

Finally, the finished pipe is crosslinked. The most technologically advanced and cheap methods of production with the use of reagents; electron beam irradiation is slower and more expensive.

The method used is not directly named: the seller's website vaguely states that "irradiation with fast electrons is the most environmentally friendly." From this we draw a cynical conclusion that, most likely, the Germans, like many other manufacturers, use the reaction with a silane and a catalyst.

The finished pipe is shipped to dealers in 200m coils. The retail price of a meter of 16 mm pipe is about 50 rubles.

Regulations

Pipes made of cross-linked polyethylene fully comply with GOST 52134-2003 "Pressure pipes made of thermoplastics and fittings to them."

What interesting things can we find in the text of this document?

In the marking, in addition to the material (PE-X), the method of crosslinking must be indicated. Definitely, it is not difficult to bring the Germans to clean water - just study the pipe.
In addition, the marking of all thermoplastic pipes includes an indication of the outer diameter, wall thickness and maximum working pressure.

The standard provides a table of pipe sizes. In the column for XLPE, we find a size variation from 10 millimeters of outer diameter with a wall thickness of 1.3 mm to 250 millimeters with walls as much as 3.4 centimeters thick.

Deviations from the given dimensions in terms of the average outer diameter are only allowed upwards and depend on the nominal size: for a diameter of 10 mm, a deviation of 0.3 mm is permissible, for 250 - 2.3 mm.

The wall thickness can also only be exceeded. Downward deviations are not allowed. The variation in deviation values is from 0.4 mm for the thinnest pipes to 3.7 for the thickest ones.

Application features

We have already found out that cross-linked polyethylene is suitable for heating. Where and how best to use it?

The ideal option is laying pipes as a warm floor. The combination of good thermal conductivity and low coefficient of thermal expansion makes polyethylene pipes more than suitable. The ability to purchase an inextricable pipe up to 200 meters long will also come in handy.

The instruction, in general, differs little from laying any other water-heated floor:

The pipe is laid out on the subfloor in a spiral or snake and recessed into the screed.
All connections are above the floor. The reason is clear: a solid pipe leaks extremely rarely. 9 out of 10 leaks are at the connections, and it would be better if they were available.
The first start of heating (see) occurs only a month after the screed is laid, when the concrete gains strength. Warming it up earlier will not speed up drying, but will cause it to crack.

It is clear that for a warm floor, the maximum operating temperature of cross-linked polyethylene is clearly excessive. Temperatures above 40C will already feel uncomfortably high. Typically, the temperature of the coolant in the pipes of the warm floor does not exceed 30 degrees.

How are XLPE heating pipes connected to brass and plastic fittings?

You will need special equipment. At a minimum - an extender, scissors for cutting will also come in handy.

The connection principle uses the molecular memory of the material: the pipe may change its linear dimensions for a while, but will quickly return to its original dimensions.

The pipe is cut to size.
A locking ring is put on it. It should protrude a millimeter beyond the edge of the pipe.
The head of the extender is inserted into the pipe and, in several movements with a twist between them, stretches the pipe, plunging further and further until the head is completely inside it.
Then the extender is quickly removed, and the stretched pipe is put on the fitting, where it returns to the original diameter and securely covers it.

Tip: The use of graphite lubricant will reduce tensile force and extend tool life.

Conclusion

You can learn more about this type of pipe by watching the video at the end of the article. Successful repair!