The feeling of comfort in the house in any weather conditions outside the window is created thanks to proper operation heating system. Its efficiency, quality and service life directly depend on the pipes. Today, installation of heating systems is increasingly carried out using cross-linked polyethylene pipes. The properties of this material allow it to be superior to other options in many ways. However, when installing such pipes with your own hands, you need to know some nuances, which will be discussed in this article.
Product characteristics
Pipes made of ordinary polyethylene (PE) are widely used to create heating, water supply, and sewage systems.
Their main characteristics include several points.
- Frost resistance, allowing the use of polyethylene structures at temperatures down to -20 degrees. This is a great advantage, since it makes it possible to carry out any work with pipes in winter, including installing new equipment or repairing failed systems.
- Resistant to high temperatures (up to 40 degrees).
- Flexibility that prevents pipes from deforming when bent.
- Plastic. Polyethylene products can expand or contract depending on temperature without losing their shape.
In order to obtain higher strength pipes, a reliable and resistant to high temperatures a material called cross-linked polyethylene (PEX).
His main feature The maximum operating temperature is 90 degrees. Sometimes such pipes can withstand temperatures of 100-110 degrees, maintaining normal operation for a certain time.
Other important feature cross-linked polyethylene pipes – high oxygen permeability. When installing such products, you must remember this property and use aluminum foil or a special polyvinylethylene coating to protect them.
Production methods
The technology of “cross-linking” polyethylene was invented in 1968 by the Swedish chemist Thomas Engel. In 1972, one of the Swedish companies put it into industrial use. This technology still leads the market today.
The purpose of the cross-linking process is to connect molecules into a three-dimensional network as a result of the formation of cross-links. During its course, polyethylene, the molecule of which contains hydrogen and carbon atoms, loses part of the hydrogen. Therefore, free bonds appear to connect molecular units with each other, as a result of which the molecules are tightly “stitched” together.
Exist different ways obtaining cross-linked polyethylene. Depends on the method specifications finished pipe. The longest, but at the same time the highest quality method is to treat polyethylene with peroxide. He gives the most high degree stitching (85%). A pipe made of such material can easily withstand low and high temperatures, resists the effects of chemicals, becomes resistant to shocks and other mechanical influences, and can restore its original shape.
Another method is to irradiate the material with electrons in an electromagnetic field. This cross-linking involves irradiating the finished product with electrons.
There is also a physical cross-linking method that uses X-rays. However, such structures turn out to be rigid. They are not resistant to extreme cold and cannot return to their previous shape.
Common is chemical method silane cross-linking. It is more effective compared to physical. This produces polyethylene that is optimal in price and quality, suitable for everyday use.
A heat-resistant, strong material, pipes from which are excellent for the installation of heating systems of any type, hot and cold water supply systems, and underfloor heating equipment is obtained as a result of each production method. You just have to choose the right characteristics, and also remember that the higher the degree of cross-linking, the higher the price of the material.
Advantages
Pipes made of cross-linked polyethylene have a number of advantages, due to which they are most often used for installation heating systems.
- Resistant to high temperatures (up to 95 degrees). Products made from cross-linked polyethylene are capable of expanding or contracting to certain sizes under the influence of low and high temperatures.
- Excellent mechanical strength achieved through good molecular memory of the material. It easily restores its original shape after deformation, unlike conventional polyethylene pipes.
- Corrosion resistance. Products made from cross-linked polyethylene are not afraid of corrosion either inside or outside (unlike, for example, copper). This quality allows you to avoid washing and cleaning PEX pipes, which is periodically necessary for their metal “brothers” and has a rather high cost.
- Guaranteed against the appearance of growths inside pipes. Unlike steel pipes, which after some time become covered on the inside with build-ups that slow down the flow rate, the inner walls of PEX pipes have a special Teflon coating and are not subject to deposits. Due to the smoothness of the internal walls, the heating system always has high hydraulics.h
- A light weight material. For example, 1 m of pipe with a diameter of 16 mm weighs only 90 g. Therefore, they are convenient to transport and easy to install.
- Easy to install. PEX products can be installed according to any scheme. They allow you to make loops and any number of bends. This does not require special welding equipment, since the pipes are connected without requiring soldering or gluing. Heating pipes are sold in 100 and 200 m lengths, which makes it possible to install large sections of the system without the use of fittings.
- PEX products are environmentally friendly and resistant to the growth of harmful bacteria inside them. The material is included in the environmentally friendly group, therefore it is widely used for drinking pipelines.
Flaws
Despite the huge number of advantages, cross-linked polypropylene cannot be called ideal.
It is worth considering its disadvantages.
- Brass fittings used to connect cross-linked polyethylene pipes for heating are susceptible to corrosion, so you have to pay close attention to the choice of materials for screed or plaster. It is better not to use materials that cause corrosion of the fitting, otherwise the quality of the heating system will noticeably decrease.
- Pipes made of cross-linked polyethylene are “afraid” of ultraviolet radiation. Therefore, they are more suitable for use indoors, in closed systems and communications. To use such products outdoors, a special protective casing is required.
- The price of such pipes, in contrast to the cost of metal-plastic and ordinary polyethylene, is quite high.
Therefore, before purchasing cross-linked polyethylene pipes, you must carefully study all the technical characteristics of the heating and water supply system of the room in which you plan to install them.
Work process
If special knowledge and skills are required when installing metal pipes, then this is not required when installing cross-linked polyethylene pipes. To do the job well, you only need certain tools and a little effort.
XLPE pipes are connected with fittings made of various materials: polymers, brass, bronze. It is best to use polymer fittings (for example, Rehau), since they are high quality, do not corrode and last a long time.
IN general outline, the installation process for PEX pipes is as follows:
- the end of the connecting structure is expanded using a flaring tool, giving it a larger diameter;
- insert the fitting fitting there;
- Using a press, the tension sleeve is pressed in, giving the greatest strength to the connection.
This technology makes pipe connections reliable and durable. The service life of such systems corresponds to the service life of the pipes themselves.
Is polyethylene pipe suitable for heating? We will get acquainted with a relatively little-known material - cross-linked polyethylene, we will analyze its features and the installation methods used.
But first, some general information.
Yes, polyethylene. Yes, on heating. No, it won't explode.
About polyethylene
What do we know about this material? Well, it's transparent... and apparently they make bags out of it. This seems to be the end of the list of generally known information.
Let's try to expand it.
- Polyethylene has been around for over a century. It was first discovered by accident by the engineer Hans von Pechmann in 1899 and was immediately forgotten.
In 1933, the material received a second life as insulation for telephone cables.
Helpful: The physical properties of polyethylene, including density and strength, vary depending on the polymerization conditions.
Moreover, the lower the pressure during the reaction process, the stronger the resulting material. There are low, medium and high density polyethylene.
- All types of polyethylene soften at 80-120C. Taking into account the fact that the pipe in the water supply will be under pressure, manufacturers limit the operating mode of polyethylene pipes to a maximum temperature of ... 40 degrees.
Hence the unequivocal and final verdict: polyethylene pipes are not suitable for heating. Dot.
Pipes made of ordinary polyethylene are not intended for hot water.
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. Stitched. 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, here is a description of a cross-linked polyethylene pipe for heating, produced in Germany under the Gabo Systemtechnik brand.
- The pipe is capable of working for the stated 50 years at 90C/7 bar or 70C/11 bar.
- 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. From a practical point of view, this means that when installing heating made from cross-linked polyethylene with your own hands, 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 temperature (see temperature chart of the heating system) in the internal engineering networks residential buildings should not exceed the same 95C, which the pipe, as we just found out, can withstand perfectly.
Make no mistake: cross-linked polyethylene can also be melted. But at a fairly high temperature.
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 pressed through the annular hole of an extruder - a special press that forms a pipe of the desired cross-section.
During the extrusion process, continuous monitoring of material homogeneity is carried out.
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 stitched together. The most technologically advanced and cheapest production methods are those using reagents; irradiation with electron beams is slower and more expensive.
The method used is not directly stated: the seller’s website vaguely states that “irradiation with fast electrons is the most environmentally friendly.” From here we draw the cynical conclusion that, most likely, the Germans, like many other manufacturers, use a reaction with silane and a catalyst.
The finished pipe is supplied to dealers in 200-metre coils. The retail price of a meter of 16 mm pipe is about 50 rubles.
The extruder in the photo turns the hot amorphous mass into a durable pipe.
Regulations
Pipes made of cross-linked polyethylene fully comply with GOST 52134-2003 “Pressure pipes made of thermoplastics and connecting parts to them".
What interesting things can we find in the text of this document?
- In addition to the material (PE-X), the marking must indicate the stitching method. Definitely bring it to clean water Germans are not at all difficult - just study the pipe.
- In addition, all thermoplastic pipes are labeled with outer diameter, wall thickness and maximum operating pressure.
The standard provides a table of pipe sizes. In the column for cross-linked polyethylene we find a range of sizes 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 specified dimensions in the average outer diameter are permissible only in a larger direction 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. Deviations to the smaller side are unacceptable. The range of deviation values is from 0.4 mm for the thinnest pipes to 3.7 for the thickest.
The standard does not contain physical properties of the material, however, this information will be useful.
Features of application
We have already found out that cross-linked polyethylene is suitable for heating. Where and how is it best to use it?
The ideal option is to lay the pipe as a warm floor. Combination of good thermal conductivity and low coefficient thermal expansion makes polyethylene pipes more than suitable. The ability to purchase an unbreakable pipe up to 200 meters long will also be useful.
The instructions, in general, are not much different 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 connections, and it would be better if they were accessible.
- The first start of heating (see forced circulation heating system) occurs only a month after laying the screed, when the concrete has gained strength. Warming it up earlier will not speed up drying, but will cause it to crack.
It is clear that for a heated 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 underfloor heating pipes does not exceed 30 degrees.
A single pipe is laid in the screed, without joints.
How to connect to brass and plastic fittings XLPE heating pipes?
You will need special equipment. At a minimum, an extender; cutting scissors 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 size.
- The pipe is cut to size.
- A retaining 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 rotation between them, it 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: Using graphite lubricant will reduce the tensile force and extend the life of the tool.
Sometimes brass rings are used, which are put on after connecting to the fitting.
Polyethylene pipes for heating: video instructions for DIY installation, features of cross-linked polyethylene, photos
121) Polyethylene pipes for heating: video instructions for DIY installation, features of cross-linked polyethylene, photo
Use of cross-linked polyethylene for heating systems
The heating system requires the use of high-quality and wear-resistant materials that are not afraid of high pressure and frequent temperature changes. All of the above stated characteristics correspond to polyethylene pipes for heating.
Cross-linked polyethylene for heated floors
In order to give polyethylene flexibility, chemical and mechanical resistance, it is cross-linked by electron flow. There are several different methods for producing cross-linked polyethylene, and depending on the technology, the technical characteristics of the material change, however, the main advantages and disadvantages are still common.
Advantages of cross-linked polyethylene
Unlike ordinary polyethylene, cross-linked polyethylene does not soften or deform when exposed to high temperatures. It is this property that allows the material to be used for heating and underfloor heating systems. In addition, cross-linked polyethylene (PEX) has the following advantages:
- Complete absence of corrosion;
- Pipes do not become overgrown or silted;
- Light weight;
- Easy installation and transportation;
- Resistant to large changes in pressure and temperature;
- Does not crack;
- Excellent sound insulation;
- Resistance to negative temperatures;
- Has molecular memory;
- It is environmentally friendly for humans and any other living organisms;
- Inexpensive cost;
- Strength;
- Long service life (according to manufacturers, it is about 50 years).
Cross-linked polyethylene for heating
Main disadvantages of the material
The positive qualities of cross-linked polyethylene have made it indispensable for heating systems and underfloor heating. However, there are still some disadvantages, among which it is worth highlighting:
- Lack of resistance to ultraviolet rays;
To reduce the destructive effect of ultraviolet radiation on cross-linked polyethylene, the pipes are coated with a special protective varnish.
- Possibility of mechanical damage, for example, by rodents;
- No resistance to surfactants;
- Destruction under the influence of oxygen.
When oxygen gets into the inner layers of the pipeline, it quickly collapses. It is for this reason that many manufacturers add a protective layer against oxygen, the so-called oxygen barrier. This reduces the risk of damage to the product, but causes an increase in its cost.
PEX pipe design and production method
The cross-linked polyethylene pipe is a multilayer structure that consists of five balls. The main layers are as follows:
- Inner ball of cross-linked polyethylene;
- Glue ball;
- Oxygen barrier;
- Glue ball;
- External ball of cross-linked polyethylene.
PEX Pipe Construction
It is this five-layer construction that ensures the high temperature resistance of the material, because it does not deform even when the transferred liquid reaches 95 ° C. That's why PEX is an excellent choice for heating and underfloor heating.
To manufacture the pipeline, the extrusion method is used, which consists of extruding the required shape from molten polyethylene. After this, all pipes undergo vacuum calibration. Products are supplied for sale in coils or cuts depending on the diameter.
Product Specifications
The unique properties of cross-linked polyethylene put it on par with many solids. Key material characteristics include:
- Melting point - 200 degrees;
- Combustion temperature – about 400 degrees;
- Tensile strength – 350 – 800%;
- Density - 940 kg per cubic meter.
Pipeline made of molecularly cross-linked polyethylene is produced in a wide range of diameters. Manufacturers offer sizes from 12 to 250 mm, but the most popular among consumers are diameters 16 – 25 mm.
PEX stitching methods
There are about 15 methods of cross-linking polyethylene, but three of them are most widespread.
Today, the following stitching methods are in demand:
A more expensive, however, and higher quality cross-linking method is peroxide. It is thanks to it that it is possible to bind about 85% of free molecules. This allows the material produced in this way to have increased resistance to mechanical stress and have a higher melting point.
PEX is the best method for producing cross-linked polyethylene; all other options are just an attempt to reduce the cost of the material.
Reinforced heating pipeline
One of the latest innovations on the market of materials for heating and underfloor heating is a reinforced cross-linked polyethylene pipe. It is even more durable and heat resistant than regular PEX. The main difference in production technology is the introduction of nylon threads into the pipe walls, which occurs at the stage of extruding the mold from hot molten polyethylene.
PEX-c cross-linked polyethylene pipes
Reinforcement methods can be as follows:
The reinforced pipeline can withstand even such loads as a pressure of 30 atmospheres and does not crack when torsioned or bent. But the cost of the products is higher, because production requires expensive equipment.
Key manufacturers of cross-linked polyethylene
Cross-linked polyethylene is the most suitable material for installing heating systems and heated floors. Today, a whole group of foreign and domestic companies is engaged in the production of high-quality and durable products. Key producers are:
Rehau is a world leader in the production of cross-linked polyethylene pipes for heating and underfloor heating.
Rehau cross-linked polyethylene
The Rehau company has taken a leading position in the world market today. It is its products that have proven themselves excellent due to their excellent quality and good performance characteristics. The price of the products is not the cheapest, so many developers are looking for more budget options for their home, for example, STOUT brand products.
STOUT is professional plumbing equipment for installation of heating and water supply systems. The products are manufactured in the same European factories where other premium brands order their products.
The main items of the STOUT product range are covered by a 5-year warranty. All parts of the system fit together perfectly, are easy to install and maintain, and are adapted for operating conditions in Russia.
XLPE pipes
XLPE pipes
Different manufacturers use various ways polyethylene cross-linking: PEX-a, PEX-b, PEX-c. Today, peroxide (PEX-a) is recognized as the best crosslinking method; it is for this reason that it is recommended to choose products from the Rehau, Uponor and STOUT brands, which are produced using this technology.
Features of material installation
Installation of heating and underfloor heating using cross-linked polyethylene can be carried out using two main methods:
- Using compression fittings;
- Using press fittings.
More simple option installation, which also allows you to repeatedly disassemble the structure at the joining point if necessary, is installation using compression fittings. To install a heated floor using this technology, you must perform the following steps:
- Place the crimp nut on the pipeline.
- Put on the split ring.
- Place the pipe onto the fitting.
- Tighten with a wrench.
Installation of cross-linked polyethylene
Attention! Be careful when tightening the ferrule nut as excessive force may damage the pipe.
Installation of heated floors using press-on fittings creates a permanent connection. It is necessary to prepare the press for installation in advance and follow the instructions below:
- Place the clamping sleeve.
- Insert an expander of the appropriate size into the pipe.
- Insert the pipe into the fitting fitting.
- Press the sleeve onto the fitting.
- Wait a few seconds and get a strong and reliable connection. Thanks to the molecular memory of the material, the pipe will be impossible to remove from the fitting.
Return to content
Why cross-linked polyethylene is better than other pipes for heating
What quality characteristics of cross-linked polyethylene should you pay attention to when choosing pipes for heating, what are these pipes made of and what is the method of cross-linking them, as well as how to install them correctly
XLPE pipes for heating: advantages and disadvantages, installation features
Low temperature heating systems are becoming more common. Modern devices and systems make it possible to heat homes at water temperatures up to 80 °C. This has led to consumer demand for inexpensive cross-linked polyethylene pipes for heating. They are easy to install and are great for installing heated floors.
Products are sold in coils, which is very convenient. It should also be noted that it is possible to minimize the number of connection nodes, which makes it possible to obtain a sealed pipeline. The described pipes have insignificant mass, and they can be used to create water supply and heating systems of increased complexity.
Using a construction hair dryer allows you to save on the consumption of materials that would be required on bends during the installation of steel products. If the pipe is heated to a high temperature, it will be able to take any shape, and when it cools, it will retain it. The advantage of these products is that they can be installed without professional help, which saves money. And you can choose the connection method that suits you.
Main advantages
Pipes made of cross-linked polyethylene for heating have many advantages, among them the following should be highlighted:
- maintaining a stable shape;
- excellent shock tolerance;
- high fatigue strength;
- resistance to cracking;
- combination of flexibility with high strength;
- excellent shrinkage characteristics;
- high wear resistance to abrasion;
- corrosion resistance;
- resistance to chemicals;
- absence of heavy metals and halogens in the composition.
XLPE pipes for heating are able to maintain fatigue strength even when exposed to temperatures up to 95 °C. The products withstand shock well, and their characteristics are maintained even when exposed to low temperatures down to -50 °C.
Main disadvantages
Pipes made of cross-linked polyethylene for heating also have some disadvantages. For example, products are sensitive to ultraviolet light. If pipes are left unprotected after installation, the material at their base will quickly deteriorate, and the pipe itself may break and become covered with cracks. It is not recommended to use brass fittings for pipes that are covered under plaster or screed. When purchasing such products, you must remember that it is not recommended to exceed their operating capabilities, as this may negatively affect durability and strength.
Installation features: selection of materials and tools
PEX pipes made from cross-linked polyethylene for heating are products with a marking, the end of which includes one of four letters: a, b, c or d. The most common recommended are the first two types - PE-Xa and PE-Xb. In this case we are talking about stitching methods.
Regardless of what technology is used in the production process, the output is a strong, complex three-dimensional polymer chain of ethylene molecules. Such products can be used for drainage, water supply and as a basis for a heated floor system. A high heat transfer coefficient is good when installing heating systems. Whereas if such pipes are planned to be used for water supply, then additional thermal insulation is necessary, otherwise the water will cool down on the way to the point of consumption.
Installation does not require highly specialized skills and special tools, however, there are some nuances that should be taken into account. When choosing fittings for cross-linked polyethylene pipes, you may prefer the crimp type, which is a compression product. Such a connection will be able to withstand pressure up to 2.5 MPa.
A welding machine can also be used for installation; with it, you can achieve a reliable connection that can withstand up to 12 MPa. In any case, the main tool will be used - a pruning knife. With the first method, you should ensure that you have wrench, in the second case you will need hydraulic or hand press, and for welding you should prepare a welding machine for cross-linked polyethylene pipes. The products are highly elastic, so during the installation process they should be held in place, ensuring fixation with special latching brackets.
Rehau brand pipes and reviews about them
These pipes are manufactured by a world-famous German concern, which sells products with a high threshold of resistance to damage. Specialists maintain a high quality standard, and pipes remain in demand and popular. According to consumers, the Rautitan series is specially designed for heating and water supply systems, because it can withstand high temperatures.
The production process uses cross-linking at the molecular level. This eliminates leakage; in addition, the pipes acquire memory when bent. The outer layer of such products is made of aluminum, which provides additional strength. As buyers emphasize, even if the outer layer is damaged during operation, the internal polymer coating will prevent leakage.
The manufacturer sells pipes with a connection technique using a sliding sleeve. The connection is permanent, which guarantees long-term tightness. Rubber O-rings are not used.
When installing Rehau pipes, there is the possibility of optical inspection. The sliding sleeve is installed according to a certain method. At the first stage, it is necessary to carry out expansion, and then insert the shaped part and push the sleeve. According to consumers, such installation can be done independently. Salts and scale do not form on the surface of the products.
Pipes provide low sound transmission and noise absorption, which is especially true when compared to metal pipes. The systems are environmentally friendly and safe. For a simple and quick connection, cold pressing can be used. If you use pipes with a diameter within 32 mm, then they can be bent without the use of tools, which, according to home craftsmen, is very convenient for private installation.
Rehau pipes are supplied for sale with a 30-year warranty, which is confirmed by tests. Although the installation of such pipes is more expensive compared to the installation of metal-plastic products or polypropylene pipes, you can be sure that such systems will last much longer.
During installation, the human factor is reduced to a minimum. Installation of such products is possible even at low temperatures, when outside the window is -15 °C. If you are interested in the diameters of cross-linked polyethylene pipes for heating, they are supplied with parameters ranging from 16 to 63 mm.
Pipe cost
Before purchasing, you should be interested in the price of a cross-linked polyethylene pipe. For Stout PEX-a the cost is 59 rubles. per meter In this case we are talking about a product 16 x 2 mm. The length of the coil is 500 m. When purchasing a Rehau Rautherm S pipe with parameters 14 x 1.5 mm, you will pay 61.96 rubles. per meter The bay is 120 m.
If the product parameters are increased to 17 x 2 mm, then you will have to pay 63.33 rubles. per meter When purchasing a Kalde PEX-b product with an oxygen layer and dimensions of 16 x 2 mm, you will pay RUB 65.27. per meter In the bay 160m.
Installation of pipes for a heated floor system
Cross-linked polyethylene pipes for heated floors are laid:
Laying with a snake is considered simpler, but the heating will not be as uniform. A distance of 35 cm should be provided between the products. One circuit should have an average length of 40 to 60 m, but not more than 120 m. Otherwise, increased heat loss will be observed, and the return coolant will have a low temperature.
Additional layers
When laying a cross-linked polyethylene pipe for underfloor heating, a thermal insulation layer is located below. The following materials can serve as it:
- Styrofoam;
- expanded polystyrene sheets;
- reflector based on foamed polyethylene.
Fastening is carried out with clips, staples or single driven dowels. Some polystyrene boards are made with an applied profile for attaching pipes. Such canvases have markings.
When pouring heating pipes made of cross-linked polyethylene, reviews of which were presented above, it is necessary to ensure expansion joints in the screed to level out linear expansion. The floor can be started after the screed has hardened. The coolant temperature must increase by 5 °C per day before reaching operating mode. If the pipe has anti-diffusion protection, then installation is carried out only after checking the top layer for damage.
Conclusion
When laying cross-linked polyethylene pipes for underfloor heating, you can use compression and press fittings. It is easier to carry out the work if you use the first fitting option, and you will need a regular nut. The thread should be directed towards the location of the connector.
Using press-on fittings, permanent connections can be formed. Docking is done using special equipment. At the first stage, a clamping sleeve is put on, and then an expander of the appropriate size is inserted into the pipe.
XLPE pipes for heating: advantages and disadvantages, installation features
Low temperature heating systems are becoming more common. Modern devices and systems make it possible to heat homes at water temperatures up to 80 °C. This has led to consumer demand for inexpensive cross-linked polyethylene pipes for heating. They are easy to install and are great for installing heated floors.
In cases where the question arises about laying or replacing heating pipes, first of all it is necessary to decide which pipes from all existing types will be chosen for this. A few years ago there was not much choice, since the only heating pipes were steel.
But their disadvantages, such as susceptibility to corrosion and short service life, practically forced specialists to develop completely different, more stable types of pipes.
Recently they have begun to be actively used. But among the diversity plastic pipes The best ones are polyethylene pipes for heating. Their advantage is durability, as 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 such pipes.
Also, polyethylene pipes for heating are good because they are made of environmentally friendly material, which is completely safe for use in residential buildings.
Polyethylene pipes are lightweight, which makes them much easier to transport parts of the heating system and, of course, themselves installation work.
Heating system made of polyethylene pipes
The installation of such pipes itself is not very complicated and, unlike welding work, unlike similar steel pipes. The result is reliable system heating with good sealing.
And if you need to repair a damaged section of the heating system, which consists of polypropylene pipes, then such replacement work is not very difficult.
Installation of a heating system made of polyethylene pipes in a house
Such cross-linked polyethylene pipes for heating, which have 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 yourself, following the following step-by-step work:
- Heating installation begins directly with the creation of a heating circuit for the house. Each building has some preferences in the heating system.
Therefore, you must initially decide which type of heating is preferable: warm floors, radiator heating or a heating system consisting of these two types. This is basically how modern houses are designed. - The next step is to calculate the thermal load. Basically, such calculations are only indicative, which are based on the modern framework of various heat losses, since cross-linked polyethylene for heating pipes also has them.
- After the necessary calculations have been made, they begin to select a heating boiler. The main thing is not to forget about the direct preparation of hot water. In the case when hot water prepare in the boiler of the building, then you can completely neglect such a boiler for heating.
If the water will be heated directly using a high-speed heat exchanger, then when choosing the maximum power of the boiler, it is necessary to take into account its maximum water consumption.
- In order to choose the necessary 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 (radial) and two-pipe.
- Both systems have good adjustability. But, despite this, in the radiator heating of a collector system, the possibility of making an error during installation work is much lower.
- Heating pipes made of cross-linked polyethylene, which is a reliable material, also require good wiring to them. Thus, collector wiring differs from other types in that it individually connects the radiator to the collector.
- Although such a system will require a higher cost of cross-linked polyethylene pipes for heating, during installation work this is compensated by the fact that various additional connections. And in this case, you will only need to tighten the nuts on the manifold and radiator.
A two-pipe heating system is installed 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 has been made and the boiler and necessary heating devices, they place directly in their places.
- Next, the installation of radiators is carried out by installing them in their places. It is necessary to place radiators exactly under window openings. This arrangement will create an air flow, which will subsequently prevent condensation from appearing on the windows.
When installing radiators, you need to know that a distance of 150 millimeters must be left between them and the floor, and between the radiator and the window sill this distance must be no less than 100 millimeters. Other distances should be determined by location and taking into account the selected heating devices.
When choosing a manifold wiring for radiator heating, radiators with a bottom connection are used, since such a bottom connection unit simply cannot be installed incorrectly. In this case, a polyethylene heating pipe will also greatly facilitate the installation of the heating system.
- The next stage of work is to install the boiler itself. To begin with, it is worth saying that it is mandatory to have a complete diagram of the heating system in order to have an idea of how it should work in this case.
If there is no final understanding of how the entire system works, 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.
You can also develop a boiler room diagram using the help of professionals or relying only on your own strength. Its simplest version uses wall-mounted double-circuit gas boilers.
Features of polyethylene pipes
When installing it yourself, it is best to use polyethylene pipes - pipes for heating. Large, given the current low cost of fittings for them, even for this small facility in the form of a personal boiler room for a home, 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 received recognition from many experts.
This material is obtained by cross-linking polyethylene and therefore has good density and impact strength.
This cross-linked polyethylene has the following advantages:
- sufficiently resistant to any corrosion;
- not at all prone to overgrowing inside your pipe;
- has fairly low sound conductivity;
- has excellent tightness;
- this material is durable;
- it is environmentally safe;
- completely hygienic;
- it can be used for hidden installation.
The good quality of such pipes is the minimal presence of connections during their installation, but at the same time they differ from their counterparts in their fairly high reliability. Also, cross-linked polyethylene pipes can withstand an unlimited amount of frozen water.
And due to the fact that these pipes are connected using axle technology, the installation process itself is completely independent of the human factor. The disadvantage of such pipes is considered high price, especially for pipes larger than 40 millimeters in diameter.
Thus, at present there is no difficulty in either choosing any material at your discretion or installing the heating system yourself. The main thing is to provide for all 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 obtain advice directly from specialists in this field.
Cross-linked polyethylene - innovative material for the manufacture of pipes. Unlike conventional PE, it can withstand high pressure, action chemical reagents, hot water.
Used for cold and hot water supply and heating pipelines.
Installation of PEX pipes is simple, but has features, knowledge of which will help you perform the installation correctly.
Pipes for heating and water supply systems made of cross-linked polyethylene
New material exhibits 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 crystal lattice substances in a solid state.
Thanks to this, flexibility is maintained, the melting point increases, resistance to thermal deformation, scratches and cracks. The material is designated PEX (PEH), 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 and cold water supply.
Advantageous areas of application:
- Warm floor.
- Heating systems, working with coolants at low temperatures.
- Indoor 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, therefore used for residential premises. When burned, it breaks down into compounds that are harmless to humans: carbon dioxide and water.
Technical properties
- Combustion temperature - 400°C.
- Melting - starts at 200°C.
- Average density - 940 kg/m3.
- Tension without breaking - in the range 350-800%.
- Retention of characteristics at temperature up to -50° C.
- Thermal conductivity - 0.38 W/mK.
- Flexibility.
When operating under standard conditions (coolant temperature within 75°C) cross-linked polyethylene will last about 50 years old. With constant use under extreme loads: high pressure, 95 degree coolant service life will be reduced to 15 years.
Standard sizes and diameter
PEX pipes are available in diameters 10-280 mm and wall thickness 1.7-29.0 mm. Supplied in coils in lengths 6, 8, 10, 12 meters each.
According to the degree of pressure resistance, cross-linked polyethylene pipes are divided into following types:
- light: 0.25 MPa (2.5 Atm);
- medium light: 0.4 MPa (4 Atm);
- average: 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
Polyethylene cross-linked at the molecular level retains positive qualities of standard PE and gains new advantages:
The disadvantages of cross-linked PE pipes include UV sensitivity and slow destruction under the influence of free oxygen penetrating into the structure from the air.
Attention! To avoid unwanted contact of PEX pipes with air, it is used anti-diffusion protection. This coating should be handled with care so as not to scratch it during installation or transportation. Products are protected from ultraviolet radiation special additives, which are included in the composition at the production stage.
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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 polyethylene pipe Rehau Pautitan flex, suitable for any type of heating.
- Specialized- have a narrow scope of application. Designed for a specific type of pipeline, for example, only for cold water supply or individual heating.
Depending on the conditions of use, heating pipes made of cross-linked polyethylene use water or antifreeze liquids - antifreeze.
In standard mode, heating pipes operate at maximum temperatures up to 95°C and pressure up to 10 atm. IN emergency situation they can withstand temperature changes up to 110°C with a twofold increase in pressure.
Varieties of pipes from the leading manufacturer Ononor
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 underfloor heating systems.
Photo 3. Pipes made of cross-linked polyethylene Uponor Comfort Pipe, designed for underfloor heating.
Size range of cross-linked polyethylene products 15-110 mm. Supplied in coils 50-540 meters each, 6 meter sections.
German company REHAU produces a large assortment of pipes of the series RAUTITAN:
- FLEX- They are flexible and are used for cold and hot water supply, floor and radiator heating of residential premises.
- STABIL- universal, have an internal aluminum layer.
- HIS - universal use V temperature conditions up to 70° C up to 10 Atm.
- PINK- for underfloor heating, radiator wiring in residential and public buildings.
Connection - fittings with a sliding sleeve, size range 12-250 mm. Pipes are supplied in straight lengths 6 m each or in bays of 25-125 meters.
Installation
There are three ways to connect PEX elements:
- Compression fittings - suitable for water supply (cold and hot). If necessary, the water supply system can be dismantled at any time.
- Press fittings- a permanent connection is obtained. The method is based on the ability of cross-linked polyethylene to recreate its shape.
- Electrofusion fittings- the most durable and reliable connection. The method requires skills when working with welding equipment.
Attention! When choosing an installation method, consider the pressure that will be in the system. Compression fittings withstand up to 2.5 Atm, press fittings - up to 6 atm, electric welded - provide a monolithic connection.
Tools
Depending on the installation method you choose, you will need:
Electric welded couplings- type of fitting in the form of a sleeve with built-in heating terminals.
Reference! Fittings are connecting elements of a pipeline used for assembly and joining, making branches, and turning pipes. Main material: brass, but polyethylene, polyvinyl chloride, polypropylene, and combined parts are produced.
Preparatory work
Before starting installation, ensure that the work area is clean - the connection points dust and dirt should not penetrate.
Using the radiator wiring diagram as a guide, prepare required number of fittings and pipes. Cross-linked polyethylene is flexible, so secure the pipes to the wall with brackets.
Check collector outputs- they must be in good condition. To avoid the formation of condensation on a “cold” system and heat loss from pipes hot water, prepare additional thermal insulation.
Operating rules and connection to the radiator
- A high-quality cut is the key to a tight joint. Cut the pipe strictly at 90°- perpendicular to the horizontal axis.
- Make sure that the cutting surface is absolutely flat- without cuts, roughness, waves.
- For connections, choose only specialized fittings- for cross-linked polyethylene.
- If a pipe bend is required, first warm up the bending area with a hair dryer.
- When using the electric welding method Monitor the temperature of the device. Cross-linked polyethylene can overheat and burn.
- For high-quality installation Follow the pipe and fitting manufacturer's instructions.
High-quality heating of a house or apartment is the key to comfort and coziness of living. And this depends, not least of all, on the quality of the created heating system. Today, for these purposes, manufacturers offer many different materials that significantly simplify installation work and increase 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 selection should be approached with maximum responsibility. Gone are the days when VGP steel pipes were practically the only option. Modern choice rich. For example, cross-linked polyethylene 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 is suitable, during 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, familiar polyethylene, sold in the form of, for example, films of various densities, is the same material from which water supply and heating circuits are made. For products that will experience considerable operational loads, cross-linked polyethylene is used. And the key word in the name is still “stitched”. Yes, the basis is the same, but the differences lie in the features of the molecular structure.
We will try to clearly explain the difference.
Ordinary polyethylene has a linear molecular structure. Long chains of linear molecules are not connected to each other. Therefore, the material is not very resistant - it is easy to break it by mechanical action, and even with not very high heating it begins to “float”.
Technological chemists tried to slightly change the molecular structure of the material, namely, to try to connect linear molecules with cross-links.
During the production of this material, molecular chains are “cross-linked”, thereby creating numerous stable cross-links. In fact, linear structure turns into three-dimensional. 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 are created, the higher the degree of cross-linking 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 a product made from this polymer. So, with increasing 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 its previously specified original shape. Agree that this is a very important advantage for a heating system.
Polyethylene pipePE-RT
An innovative development in the production of pipes has become products made from polyethylene PE-RT (polyethylene with increased heat resistance - “Polyethylene of Raised Temperature Resistance”). By and large, this type of polyethylene cannot be fully called a cross-linking product. The fact is that the initial granular raw materials from which products are made have 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 makes it possible to control the processes of spatial formation of macromolecules. These developments make it possible 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, eliminating the appearance of cracks or breaks during strong bending. Despite aggressive influences, PE-RT, unlike PEX, always retains its thermoplasticity. Therefore, the connection of pipes of this type can be made not only using crimp 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 therefore the heating system as a whole.
Considering the advantages of PE-RT, we can conclude that it is confidently displacing 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 cross-linking cycle. All the necessary properties to achieve the required parameters are already included in the semi-finished raw material. Interestingly, waste heat-resistant polyethylene 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 along with the coolant, without losing its original qualities and depressurizing the heating system.
- PE-RT pipes can be repaired, which is impossible for PEX analogues.
- Due to its structure, the material perfectly absorbs the sound of coolant flowing through it. In addition, due to their plasticity, they do not produce squeaks in the system, which is sometimes the problem 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 pipes made of PE-RT polyethylene 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. Manufacturers use their own developments as this layer, for example EVON or OXYDEX.
As an example, here is a table with the main technical and operational characteristics pipes PERT-AL-PERT of the rather popular production brand COMPIPE:
| 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/linear m) | 113 | 149 | 264 | 331 |
| Pipe cavity volume (l/linear m) | 0.113 | 0.201 | 0.314 | 0.531 |
| Minimum bending radius, mm | 45 | 60 | 95 | 125 |
| Outer layer (material) | PE-RT (polyethylene with increased heat resistance) | |||
| Inner layer (material) | PE-RT (polyethylene with increased heat resistance) | |||
| Aluminum layer connection method | TIG butt welding | |||
| Operating temperature, ˚С | 70 | |||
| Maximum temperature, ˚С | 95 | |||
| Maximum pressure, bar | 10 | |||
| Linear expansion coefficient, (К⁻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 the 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 PEX or PE-RT polyethylene.
Such connections have already proven their high reliability, and therefore 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 installation.
You may be interested in information about what they are
So, there are several connection methods.
One of the simplest and fastest installation methods is the option with a sliding sleeve. The whole process consists of three steps:
1 - Place a crimp sleeve on the pipe and move it away from the edge by about 100 mm. Then, the pipe cavity at the edge is slightly expanded with a special expander. This is necessary so that the fitting can easily fit into it.
2 - Next, the fitting is inserted into the expanded channel of the pipe until it stops. Since cross-linked polyethylene will tend to return to its original shape after the expansion process, it will press tightly against the material of the connecting part.
3 - At the final stage, the sleeve that was put on earlier is shifted, closing the created connection. This way, the polyethylene will be tightly clamped between the fitting and the sleeve. Shifting the sleeve requires considerable effort, so it is done with a special tool.
Another option, already mentioned above, is suitable for connections of both pipes made only from polyethylene and metal-plastic ones. This method includes approximately the same stages of work, but at the end of the process, the sleeve moved to the edge of the pipe is crimped with special pliers.
You might be interested in information about what it is
PERT-AL-PERT pipes can be connected using a fitting and a ferrule nut:
- First, the union nut is put on the metal pipe, then the crimp ring.
- Then, after slightly flaring the edge, a metal fitting is inserted into the pipe until it stops, which often has rubber sealing rings, but may also be without them.
- The next step is to first slide the ferrule ring onto the edge of the pipe, and then the nut on top of it.
- The nut is screwed tightly onto the thread of the fitting.
This connection method does not require special tools- just have a wrench or wrench on hand. However, according to experts, such pipe connecting units are not highly reliable. A leak may appear 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 inspection.
Another installation method is diffusion welding, which can only be used to connect PERT-based pipes. Of course, special fittings must be available for such installation.
This work is complicated by the need for 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 mastered very quickly even by beginners.
You may be interested in information on how to install
Advantages and disadvantages of cross-linked polyethylene 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 in PE-RT pipes.
- Excellent strength characteristics - the pipes are resistant to external mechanical influences and internal baric loads.
- The elasticity of the material allows the pipes to be used in complex schemes laying with many turns under a small radius.
- Even after serious deformations, the pipe tends to restore its shape.
- Inert 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 likelihood of insoluble deposits on the internal walls is almost completely eliminated, even if low-quality coolant is used.
- Low weight of pipes and long length in coils speeds up and simplifies installation work on laying long contours.
- High reliability of connections.
- The environmental friendliness of the material allows them to be used for installation in a water supply system, from which water 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 have a complete understanding of pipes made of this material, it is necessary to highlight them flaws , since they are also available:
- Both PEX and PE-RT pipes have relatively low resistance to ultraviolet radiation. Therefore, it is better to use them in closed areas (the same contours of a “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 to have a special installation tool, and the skills to work with it.
- Great care should be taken when using cross-linked polyethylene pipes in a heating system connected to a central heating system. In any case, it is better to check the acceptable operating parameters several times and compare them with possible operating modes of the system, about which you need to obtain information in advance from local utilities.
You may be interested in information about what is involved in a 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, the main thing we can advise is to choose materials from truly reputable manufacturers in order to “bite your elbows” due to problems that begin during installation or, worse, already during operation of the system.
Pipes produced 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 for now, professionals still prioritize imported products.
The table below shows several pipe options that are well suited for installing a “warm floor” system. Prices are average, and in different regions they may differ from those shown - this is easy to check on the spot.
| Manufacturing company and pipe model | Brief technical specifications | Coil length | Price per linear meter |
|---|---|---|---|
| Uponor PEXа evalPEX Q&E 16 x 2.0 | Diameter 16 mm. Cross-linked polyethylene PE-Ha, wall 2 mm, t max - up to 95 degrees, (short-term heating up to 110) | 50 – 240 m | 130 rub. |
| Uponor PEXа evalPEX Q&E 20 x 2.0, | Diameter 20 mm. Cross-linked polyethylene PE-Ha, 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 plastic, PE-Xc/AI/PE wall 2.6 mm | 100 m | 175 rub. |
| REHAU "Rautitan stabil" | Diameter 20 mm. Metal-plastic, PE-Xа–AL–PE wall 2.9 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 swing - up to 90 degrees | 120 m | 150 rub. |
| Contour PERT D 16 red | Diameter 16 mm. Monolayer PERT pipe Russian production., t max – up to 90 degrees, pressure – up to 6 bar. | 200 m | 55 rub. |
| BioPipe PERT 16x2.0 | Diameter 16 mm. | 240 m | 50 rub. |
| Thermotech MultiPipe PE-RT II, 16*2 mm | Diameter 16 mm. Five Layer PERT Pipe with Diffusion Barrier | 240 m | 150 rub. |
The presented selection deliberately does not show the pipes of the lowest price category, as well as products from dubious or completely unknown manufacturers. The reasons are probably clear - the author simply does not have the moral right to recommend such material for installing a heating system that is designed to last for several decades of operation.
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