Plastic pipes for heating characteristics

More than 20 years ago, plastic pipes intended for heating—the features of which will be discussed in publications—firmly established themselves in the building materials market and went on to become extremely well-liked. There are numerous variations with varying manufacturing materials and, thus, application areas.

Plastic tubing for heating properties

Certain plastic pipes are primarily used to arrange how coolant from the boiler circulates through heat exchangers. Others are perfect for laying the patterns of water on "warm floors" because of their flexibility and plasticity. Furthermore, certain types can be rightfully referred to as universal since they work with practically any heating system unit that is installed.

Prior to examining the different kinds of plastic pipes and knowing which one to use for heating, it’s important to determine exactly what specifications the pipes must fulfill in order to be installed in the heating system.

Pipe selection criteria for heating systems

Installation of pipes in the heating system requires them to meet certain requirements because these pipes experience unique loads that are primarily related to temperature changes. It is not reasonable to choose a pipe based solely on installation ease or low cost if you want your heating system to be dependable and run for a long time without having to worry about emergencies.

There is a wide variety of pipe products available for purchase these days. Their dimensional parameters, such as wall diameter and thickness, manufacturing material type and quality, linear expansion, flexibility, reinforcement presence or absence, resistance to temperature and baric loads, UV radiation resistance, etc., vary. However, if pipes are chosen for heating, they need to have the following qualities:

• Pipes should steadfastly withstand the high temperatures of the coolant passing through them. According to the standards in the central heating system, the temperature of the coolant should not exceed 70 ÷ 75 degrees, but the pipes need to be purchased with the operational “margin”, that is, with the characteristics calculated at least 90 ÷ 95 degrees. They must maintain their density in unforeseen extreme situations, and the plastic should not somehow react to increased heating, so as not to cause deformation of the laid contours.
• At elevated temperatures in the heating system, the pressure always increases. This means that pipes should be guaranteed to withstand baric loads and hydraulic boards. This quality is especially important for pipes installed in the contours connected to the central heat supply system, where it is much more difficult for the housing owner to control the corresponding parameters.
• Heating pipes should have a perfectly smooth inner surface, which will help to avoid significant deposits of scale and dirt from low -quality coolant, which can create excessive resistance for normal circulation of liquid.
• The material of the manufacture should have a minimum coefficient of thermal expansion, otherwise, when exposed to high temperatures, the pipe will begin to sag or an increased internal voltage of the walls will be created in them, in which they will begin to bend.
• Polymer pipes are not exposed to an aggressive environment and the occurrence of corrosion processes – this quality is the best suited for using them in the heating system.
• Pipes should be designed for a long service life, which cannot be lower than other elements of the heating system.
• The coolant should circulate inside the system silently, since not all owners of housing are pleasant to the sound of murmurous water. Unlike metallic pipes, polymeric ones are able to provide movement without swirls and sound resonance.
• An important quality to maintain harmony in the interior is a neat appearance of heating pipes.

Contemporary technologies for the production of plastics and composite materials enable the production of pipes that nearly perfectly meet the aforementioned requirements. Polypropylene and polyethylene pipes in various combinations, including those with aluminum reinforcement, are the most widely used and frequently arranged shapes for heating systems; these pipes are referred to as metal-plastic pipes.

You might be curious to know what qualities a stitched polyethylene pipeline is guaranteed to have.

You should weigh your options because the pipes in the heating and hot water supply system are dependent on the quality of all the materials used during manufacturing.

Polypropylene pipes for the heating system

Although polypropylene (PP) has long been used as a raw material for pipes, it wasn’t until recently that this material could be used for products that were subjected to high pressure and temperatures.

Premium polypropylene pipes work great with heating systems, but they don’t work well for "warm floor" contours.

Although polypropylene pipes can withstand a wide range of chemicals, they differ greatly from one another in terms of strength and heat resistance. Three distinct types of polypropylene each have their own name:

• The first type (pp-n) has high strength and inertia to chemical influences, but is not able to withstand high temperatures. Therefore, they are used for cold water supply, drainage and ventilation systems, as well as for other needs, where the contact of the material with heated fluids is not supposed.
• The second type (PP-V or PP-2)-retains all the positive qualities of the first type of material, but is able to withstand minimal thermal loads. For example, a temperature of 85 ÷ 90 degrees this material will not withstand even a short time. Pipes with such labeling can be used with a certain convention in hot water supply systems or in the “warm floor” systems, where heating of the coolant does not exceed a temperature of 50 degrees.
• The third type (RRRC, PRR or PP-3) is designed for use in heating and supply systems of hot water, since such polypropylene racks to thermal and compression loads. This material is made using technology when, during the synthesis process, ethylene molecules are built into the molecular chain, which makes products from it more persistent and durable.

The primary material used to produce pipes with a variety of applications is polypropylene PP-3.

You can choose a pipe that best matches the color scheme of the room because, contrary to popular belief, this does not indicate any special qualities or characteristics of the pipes.

Many manufacturers paint red or blue stripes on the pipes’ exteriors. This one is simple to figure out because the blue stripe indicates that the pipes can only be installed in the cold water supply system, and the red color clearly indicates the heat resistance of the material used to manufacture the pipes.

Various kinds of pipes made of polypropylene

Though not all products have these designations, it is still advised to pay attention to the letter marking initially.

PRR, the third kind of pipes, is further broken down into multiple parameters. First and foremost, these are the product diameters and wall thicknesses. Standard diameters used for heating at home are 16, 20, 25, 32, 40, and 50 millimeters. The designation also specifies the working pressure that the pipe is intended to withstand. There are four different working pressure types in total: PN -10, PN -16, PN -20, and PN -25.

Type of polypropylene pipes	Nominal working pressure		The field of use of pipes
MPa	technical atmospheres (kgf/s²)
Pn -10	1	10.197	Cold water supply or heating system with heating of the coolant not higher than 45 ° C
Pn -16	1.6	16.32	Cold and hot water supply with a temperature of not more than 60 ° C.
Pn -20	2	20.394	Cold and hot water supply or autonomous heating systems with a low level of coolant pressure and a painted absence
PN -25	2.5	25.49	Hot water supply and heating with coolant to 90 ÷ 95 ° C, including for the central heating system.

Long laboratory and operational tests of all kinds of pipes produced the specified data. The recommended parameters should be considered when choosing the material, rather than attempting to save a few pennies.

The standard linear parameters of several types of polypropylene pipes are shown in the table below. In this instance, "h" denotes the wall’s thickness and "Ø VN" denotes the pipe channel’s inner diameter.

Type of pipe	Pn -10		Pn -16		Pn -20		PN -25
The outer diameter of the pp pipe, mm	Ø VN (mm)	H (mm)	Ø VN (mm)	H (mm)	Ø VN (mm)	H (mm)	Ø VN (mm)	H (mm)
16	–	–	eleven.6	2.2	10.6	2.7	–	–
20	16.2	1.9	14.4	2.8	13.2	3.4	13.2	3.4
25	20.4	2.3	18	3.5	16.6	4.2	16.6	4.2
32	26	3	23	4.4	21.2	5.4	21.2	3
40	32.6	3.7	28.8	5.5	26.6	6.7	26.6	3.7
50	40.8	4.6	36.2	6.9	33.2	8.4	33.2	4.6
63	51.4	5.8	45.6	8.4	42	10.5	42	5.8
75	61.2	6.9	54.2	10.3	50	12.5	50	6.9
90	73.6	8.2	65	12.3	60	15	–	–
110	90	10	79.6	15.1	73.2	18.4	–	–

Additionally, the following table will clearly demonstrate how long a pipe’s service can be counted for based on its type and operating parameters, such as coolant pressure and temperature.

The temperature of the coolant ° C	Service life, years	Type of pipe
PN-10	PN-16	PN-20	PN-25
Permissible pressure (kgf/cm²)
20	10	13.5	21.7	21.7	33.9
	25	13.2	21.1	26.4	33
	50	12.9	20.7	25.9	32.3
thirty	10	eleven.7	18.8	23.5	9.3
	25	eleven.3	18.1	22.7	28.3
	50	eleven.1	17.7	22.1	27.7
40	10	10.1	16.2	20.3	25.3
	25	9.7	15.6	19.5	24.3
	50	9.2	14.7	18.4	23
50	10	13.9	17.3	23.5	21.7
	25	8	12.8	16	20
	50	7.3	eleven.7	14.7	18.3
60	10	7.2	eleven.5	14.4	18
	25	6.1	9.8	12.3	15.3
	50	5.5	8.7	10.9	13.7
70	10	5.3	8.5	10.7	13.3
	25	4.5	7.3	9.1	eleven.9
	thirty	4.4	7	8.8	eleven
	50	4.3	6.8	8.5	10.7
80	5	4.3	6.9	8.7	10.8
	10	3.9	6.3	7.9	9.8
	25	3.7	5.9	7.5	9.2
95	1	3.9	6.7	7.6	8.5
	5	2.8	4.4	5.4	6.1

It is best to install PN-25 pipes, which are perfect for any heating system, but as you can see from the characteristics presented, PN-20 pipes are acceptable for the heating and hot water supply system, taking into account the temperature features.

"Pros" and "Cons" polypropylene pipes

There are numerous benefits to installing polypropylene pipes in the heating circuit, including:

• The ease of material will allow the pipe to the place of their installation independently, without additional specialized equipment.
• Polypropylene RRR is easily installed using welding using a special apparatus, which can be rented for a certain time. Having understood the simple technology of working with the device, the installation process will be completely simple and on its own.
• The material is harmless to humans, and the hot coolant does not change its chemical composition.
• Special substances – stabilizers that make up polypropylene make it resistant to thermal loads and hydraulic boards, which occur in a centralized heating system. Thanks to the plasticity of the material and fairly thick walls, the pipes can withstand even freezing inside them without gap.
• Polypropylene is able to dramat all the sounds that can occur during the circulation of the coolant inside the circuit.
• All types of water pipes from this material, as well as components to them, have a very attractive price.
• A wide range of various components of parts allows you to quickly assemble a structure of any degree of complexity.
• If high -quality material is purchased, and installation is also correctly carried out, the heating system will last a long time.
• Polypropylene pipes have a neat appearance, so they do not require special decoration, cleaning and painting.

Naturally, there are drawbacks to this material, which also require some discussion:

• Polypropylene does not protect the coolant from the penetration of oxygen, which contributes to the occurrence of corrosion processes on the metal elements of the contour, and in the autonomous system – including in boiler equipment. In addition, oxygen can contribute to the development of aerobic bacteria, the colonies and life products of which over time can narrow the inner lumen of the pipes. A similar phenomenon can significantly reduce the normal circulation of the coolant.

Many manufacturers "dress" pipes in metal or chemical-organic tissue barriers in an attempt to eliminate this problem.

Thus, the following labeling can be placed, for instance, on the outside of a polypropylene pipe that has aluminum reinforcement, which will help to reduce linear deformation and act as an anti-oxide barrier:

PP-RCT-Al-PPR,

Which is, in actuality, the "formula" for the product’s multilayer structure (layer labels are always indicated from the internal to the exterior):

Pipe made of polypropylene reinforced with aluminum

1. Random-polymer polypropylene modified by PP-RCT that has better thermostatic qualities;

Two Al layers of reinforcement made of aluminum;

3- PPR — Polypropylene’s outer layer.

4-a unique layer of adhesive that joins all the components to form a single structure.

• Another drawback of polypropylene can be called a sufficiently large linear thermal expansion. This “minus” can appear when installing pipes in a system with a coolant with high temperatures.

Reinforcing the pipe is another way to eliminate the deficiency; in this instance, fiberglass is frequently utilized for this purpose. The "formula" of the pipe or the schemes for the letters FR or FG both denote the existence of this layer.

Fiberglass-reinforced pipe

Fiberglass does not stop oxygen from penetrating, but it does help to effectively handle thermal expansion. This leads us to the conclusion that installing pipes in a heating system with an aluminum reinforcing layer will be the most advantageous choice. He will be the one to tackle two issues at once: he will greatly lessen the temperature expansion and shield the coolant from oxygen leaking in.

The table below provides some examples of different multi-layer and single-layer pipe types for better understanding of temperature expansion and oxygen diffusion:

Types of polymer pipes	Designation ("formula" pipes)	The temperature line of linear expansion, mm/m × ° C	Oxygen diffusion indicators, mg/m² per day
Single -layer pipes:
From stitched polyethylene.	PEX	0.2	650
Polypropylene	PPR	0.17	900
Multilayer pipes:
Made of stitched polyethylene with a barrier layer.	PEX-EVON-PE	0.2	0.32
Polypropylene, reinforced with fiberglass.	PPR -FG -PPR	0.035	900
Polypropylene, reinforced with aluminum.	PPR- Al -PPR	0.026	0
Metal -plastic of polyethylene with increased heat resistance	PERT -L- PERT	0.025	0

Data for polyethylene pipes are included in this table and will be discussed later.

Since polypropylene is not a plastic material, all required bends, turns, and other shapes must be welded from straight segments of the pipe when constructing the contours. This includes even tiny bends and turns. While it is generally simple to accomplish, it is not always practical. Furthermore, limitations on the use of polypropylene pipes are occasionally placed for this exact reason—they are inappropriate for the "warm floor" contour, which must be completed using a complete piece of pipe in accordance with the regulations.

When analyzing the outcomes of polypropylene pipes, the following conclusions can be made:

Only an excellent layer of aluminum reinforcing will help eliminate all of polypropylene’s drawbacks; PN-25 pipes are typically made with this option in mind. This layer can greatly slow down the temperature’s linear expansion and serves as an efficient oxygen barrier. These pipes have an aluminum layer that is 0.4 ÷ 0.7 mm thick.

Heating polypropylene pipes

Polypropylene pipes for heating

Video: Recommendations for the choice of polypropylene pipes for the heating system

Installation of polypropylene pipes

We will quickly go over the technology involved in installing polypropylene pipes just to be sure that even a complete beginner with no prior experience can handle it.

An excellent set of tools for soldering polypropylene pipes

It will be necessary to buy or rent a specific device in order for the installation to function. Typically, a single working case houses every welding tool. It is evident from the illustration that a welding set, complete with a specialty soldering iron, is shown. The device’s working heating element has holes for attaching the coupling and dorn, which will heat the pipes and connecting elements prior to welding. Several pairs of foot and dorn, intended to connect pipe of different diameters, are typically included in the kit. Frequently, the kit comes with extra scissors for cutting them.

You will also need a pencil or marker, a roulette to mark the installation site and measure the desired pipe segments, and a construction level, which, if needed, regulates the evenness of the pipe installation on the walls.

The device must reach high temperatures—roughly 270 °C—in order to melt polypropylene, so you should wear gloves out of caution to avoid inadvertently getting severely burned.

In the event that PN-25 or PN-20 pipes with aluminum reinforcement are utilized for installation, the upper polypropylene and reinforcing layer must be removed prior to soldering from the pipe’s extreme section to the depth of the ram. Shaver is another tool that is used for this. This pipe cleaning tool can be used manually or as a screwdriver or drill nozzle.

Shaver for handling pipes with reinforcement

You may, for instance, think about welding a single seam, which is done in the following order:

• On two sides of the heating element of the soldering iron, heating pairs are screwed into special holes – dorn and couplings, the desired sizes, which will correspond to the diameter of the pipes installed in the outline.

When using pipes with varying diameters, the device is designed to accommodate two or, in cases where it is necessary, three pairs of nozzles.

• Next, the device is included in the network for warming up. The desired temperature is set on the thermostat, so for polypropylene it is considered optimal to heating the soldering iron to 260 ÷ 270 degrees. On some solderingrs, regulators are installed on which the temperature for welding of certain pipes is already indicated.
• It will take about 10 ÷ 15 minutes to heated the device to the required temperature, and during this time you can prepare pipe segments and the necessary profile elements (corners, taps, tees, adapters, taps, connecting unit “Americans”, etc.D.) Heated and mating sections of pipes and connecting parts should be clean. If necessary, they can be wiped with an alcohol solution.

Using specialized scissors to cut blanks

When cutting pipe, precise perpendicularity and burr-free cutting are required, and this is accomplished with specialized scissors.

• If PPR – AL – PPR pipes with a reinforcing layer close to the outer surface are used, then the edges of the segments must be cleaned with the shaire. To do this, the pipe is inserted into the cutting part of the tool, then it is turning, cutting off the upper PPR layer and the reinforcing aluminum layer, otherwise the pipe and other details will not work. Cleaning goes to the stop of the end of the pipe into the shaver cylinder – it is the necessary depth of the future ram.

Removing a welded joint using a razor

It should be mentioned, though, that polypropylene reinforced by aluminum pipes is done without the need for cleaning because the reinforcing layer is positioned quite deep beneath the PPR layer and won’t obstruct welding. Even visually, it is simple to ascertain.

It is not necessary to clean the pipe if one with fiberglass reinforcement is utilized.

The depth of the ram is measured on the pipe from the edge and marked with a marker if it hasn’t been cleaned with a shaver. For pipes with different diameters, this value stands alone.

Furthermore, it is a good idea to try the mutual location of the pipe segment and the attached element beforehand. Risks that will only come together when welded can serve as indicators of the selected position.

• When the soldering iron warms up, the indicator light will notify this, which will turn off when the temperature is necessary for welding.

Heating of the connecting element and pipe

• The connecting part is put on the Dorn, and the pipe is inserted into the coupling to the end of the site, from which the reinforcing layer is removed, or to a previously affixed mark. Both parts must be worn at the same time to get uniform heating.
• Next, the time required to fully warm up the connected surfaces is calculated. After it, the elements are removed from the soldering iron and quickly interconnected, that is, the pipe is inserted into the connecting element to the depth of the heated area. At the same time, if necessary, the marks of the mutual arrangement of parts are combined and.

Joining of the components following initial heating

Since the connected elements are copoly (they screw into each other rather than into each other), they cannot be turned after they are connected.

• The details are held in a given position until completely cooled, about 20 seconds.

The primary parameters required for this type of welding work are displayed in the table below: the depth of the pipe heating, the heating time, and the amount of time needed for the created connection to fully polymerize (become fearless of loads).

Ø pipes in mm	The depth of the pipe heating during welding, mm	Heating time (seconds)	The term from the connection of the elements to the full polymerization of the seam (minutes)
20	14 ÷ 16	6	2
25	15 ÷ 17	7	2
32	16 ÷ 20	8	4
40	18 ÷ 22	12	4
50	20 ÷ 25	18	4
63	24 ÷ 30	24	6
75	26 ÷ 32	thirty	6
90	29 ÷ 35	40	8

If, for some reason, the seam did not work out or its quality raises questions, the only way to fix the situation is to cut the problematic section and replace it with a new segment and the connecting element. Taking extra precautions and waiting a few minutes is preferable to leaving a suspicious knot.

The description of the installation work shows that these are not particularly difficult tasks, and one can pick up this technological operation very quickly. A small margin should be allowed when buying pipes and other heating circuit components. You should also buy a few extra of the cheapest connecting parts in order to create multiple "training" seams.

Polyethylene -based pipes

Polyethylene pipes are another type of pipe used in heating or water supply systems. It goes without saying that this is not the material used to make packaging or other items for daily use in the home; rather, it is enhanced polyethylene that can withstand sufficiently high loads.

The modified polyethylene used to make these products comes in two primary varieties.

"Stitched" polyethylene

The linear structure of ordinary polyethylene is made up of unrelated or weakly connected molecules. This indicates that the material is insensitive to heat effects because, even at very low temperatures, it soon starts to "swim." However, the picture drastically changes if the molecules are "sewn," or connected transversely, retaining all of the material’s existing benefits while adding new ones.

"Stitched" polyethylene pipe

The material that is "sewn" at the molecular level gains several enhanced positive properties that enable you to greatly broaden the range of applications for it. Warm polyethylene that has been sewn becomes more heat-resistant and resilient without significantly losing its elasticity. Furthermore, an intriguing phenomenon known as "memory" emerges: under high mechanical loads, the material attempts to return to its original form as quickly as possible when heated.

A material’s strength and quality increase with its stitching level, which is directly proportional to the number of intermolecular ties in its structural structure.

Although production processes vary, all "stitched" polyethylene bears the Rex marking.

• The highest degree of molecular “stitching” is the processing of polyethylene raw materials with peroxide – with this technology, the level of transverse ties can be up to 85%. This type of polyethylene is marked with rex, and is considered the highest quality in this line of materials. True, it is the most expensive, since the controlled technological process of its production is quite complicated. Pipes with this marking are quite suitable for the heating system.
• The simpler “stitching” method is the effect on polyethylene raw materials with special reagents (“vaccination”) and hot water steam – in this case, the “stitching” parameter is only 65%. A similar material rex-b is marked. Such polyethylene has lower quality, since after its manufacture the process of “stitching” does not completely stop, so over time the pipe loses its elasticity, becomes more rigid, changes its other physical data, giving a kind of “shrinkage”. This phenomenon leads to clocks on the compounds, which means it will require constant control, and, if necessary, the timely lifting. Pipes with this marking according to European standards are considered unsuitable for installation in systems with elevated temperatures of the coolant circulating under pressure. True, many of our masters often ignore this, and use them as a cheaper option.

When laying a "warm floor" system, REX-B pipes can be used as long as the coolant temperature stays below 45 degrees and no additional connections are made; in other words, the laid contour should be integral the whole way along.

• REX-C-this type of “stitched” polyethylene is obtained as a result. This method is inexpensive and quite productive – as a result, benign products are obtained, quite suitable for use in tap systems. But for heating with high temperatures from such pipes it is better to refuse.

Polyethylene of increased heat resistance PE-RT

PE-RT is a polyethylene mark that indicates higher heat resistance. Even during the raw material synthesis stage, a change in the material’s molecular structure takes place based on entirely different principles.

Polyethylene (PE-RT) pipe

The following characteristics make pipes made of this material ideal for heating systems:

– consistently withstand elevated intrasystemic pressure and temperature;

– These pipes have a 45 ÷ 50 year stated service life;

-PE-RT pipes can be welded, unlike REX pipes, which allows for repair and restoration work to be done without having to disassemble the damaged area.

– The fluid inside the pipes won’t freeze because this kind of polyethylene is very elastic. They don’t need to be repaired or reinstalled in order to function in the same mode after thawing.

The cost of PI-RT pipes

Pip PE-RT

Varieties of polyethylene pipes

Similar to polypropylene pipes, polyethylene pipes can have reinforcement or not.

Single -layer pipes that do not have reinforcement

These PE-RT and REX pipe options are excellent for defining the boundaries of the "warm floor" system, as was previously mentioned.

Single-layer pipes are better suited for laying the "warm floor"’scontours.

The following table compares the features of the two most popular PE-RT pipes, which have a diameter of 16 × 2 and 20 × 2 mm.

Operational and technical characteristics of PE-RT single-layer pipes without reinforcement	PE-RT 16 × 2 mm	PE-RT 20 × 2 mm
Pipe volume (liters/linear meter)	0.113	0.201
Mass (kg/linear meter)	0.07	0.127
Minimum bending radius – 5D (mm)	60	100
The temperature of the coolant (° C)	20	20
Working pressure (bar)	20	20
Service life (years)	More than 50	More than 50
Temperature (° C)	75	75
Working pressure (bar)	10	10
Service life (years)	More than 50	More than 50
Temperature (° C)	95	95
Working pressure (bar)	6	6
Service life (years)	More than 50	More than 50
Permit pressure (bar)	6	4.5
At temperatures (° C)	110	110
Permit pressure (bar)	eleven	10
At temperatures (° C)	90	90
Max linear extension coefficient at a temperature of 95 ° C (mm/m × ° C)	0.18	0.082
Thermal conductivity coefficient (W/m × ° C)	0.41
Roughness of internal surfaces (μm)	0.125 (class 10)
The calculated strength of the material (MPa)	6.3

These pipes can be single-layer, but just like with polypropylene, there’s a chance that the walls will diffuse a lot of oxygen. Thus, in order to get rid of this problem, some producers offer an additional layer called the protective barrier Evon, which is a sophisticated copolymer based on ethylene-vinyl alcohol.

PE-RT pipe featuring Evon’s anti-face barrier

Metal -plastic pipes based on polyethylene

Most of the time, metal-plastic pipes are referred to as polyethylene products with an aluminum layer inside. These consist of Rex – Al – REX, PERT – Al – REX, Pert – Al – Pert, and even a hybrid version of PERT – AL – PPR with polypropylene as the outer layer.

The following table compares some features of plastic and metal pipes using heat-resistant and stitched polyethylene:

Operational indicator of products	Rex – Al – Rex	Pert – al – pert
Nominal operating temperature ° C.	95	95
Short -term permissible peak temperature ° C.	110	124.7
Elasticity of the walls of the pipe, MPa	1100	660
Method of connection	Only mechanical – fitting or threaded	Mechanical fittings and thermoplastic welded fitting compounds.

Similar to polypropylene, the aluminum layer serves as a barrier to protect tissue, enhances product mechanical properties, and increases pipe resistance to heat changes by decreasing linear expansion. Furthermore, metal-plastic pipes work far better at maintaining the curved shape to which they are attached.

Purchasing metal and plastic pipes from specialized stores is advised, as the seller can verify the goods’ quality with the relevant certificate. Avoiding spontaneous markets is advised, as prices there may be low, but the products themselves are frequently low-quality items from unidentified manufacturers, which can lead to many unpleasant "surprises."

Remember that over time, even relatively high-quality options may cause a stratification between the polymer and aluminum layer during their operation. One could argue that, in the case of cheap pipes, stratification is inevitable and will only take time to manifest. Such wall destruction is dangerous because it increases the risk of a pipe breaking and hollowing out. If this occurs in an exposed section of the pipeline, the most catastrophic outcome could be a leak in the finish coating or screed of the "warm floor" circuit.

Therefore, cutting back on heating is not advised because there will be significantly higher costs in the event of flooding in your apartment and, more importantly, in the case of neighboring expenses.

Installation of polyethylene pipes

There are various methods available for installing heating circuits with a polyethylene basis, including compression, pressing, or specialized welding fittings.

A range of pipe installation connecting fittings

All polyethylene pipes install essentially the same way, but some manufacturers create unique connecting components for their products that set them apart from the rest.

Fittings with compression threading

Selecting metal-plastic pipes with compression threaded fittings is the most comfortable option if the contour is installed independently, at home, and without the need for a specialized tool.

Disassembled compression fitting with a threaded pendant nut

Pipe wiring assembly is a very easy process that involves the following steps:

• The desired segment of the pipe is measured and cut off with special scissors or a knife -cutting stake on metal. The main thing is that the cut is perfectly perpendicular, even and neat, without rinseing the walls.
• Further, the fitting is disassembled, and the pipe is put on the pipes and advanced by 100 ÷ 120 mm, the compression nut, thread towards the joint, and then, in the same way – the brass cut ring.
• The inner surface of the pipe on the connection with the fitting is recommended to be divorced, that is, to expand somewhat using a manual calibrator.

Pipe collapses prior to fitting connection

• The next step into the processed end of the pipe is inserted until the fitting fitting is inserted. In this case, the rubber gasket should be in the deepening (groove) intended for it.
• The split ring is shifted close to the fitting, to its place, then the squeezing nut is shifted and twisted and twisted. The work is carried out with wrench, and it should not be tightened too tight. The tightening can only be carried out if necessary – during crimping, when submitting a test pressure, if there are signs of leakage.

• After that, in the same way, the subsequent sections of the pipe on the other side of the fitting, crane, tee, etc. are installed in the same way.P. When connecting some elements to each other, as well as when transitions to other types of pipes or threaded connections are used to the instrument nozzles.

Video: Connection of a metal -plastic pipe with compression fitting

Fittings under pressure

Press fitting installation is a more involved procedure that needs specialized tools to heat or raise fitting elements. It is possible to use this installation technology on metal-plastic and polymer pipes. Here, a unique quality of "stitched" polyethylene is put to use: it can deform and then return to its original shape.

Unit connection using pressing-style fittings

The following order is roughly followed when installing pipes with pressing fittings:

• The fitting is also disassembled, and then its sleeve is put on the prepared edge of the pipe and shifted along it.
• Next, a special expand is introduced inside the pipe. This operation is necessary to expand the mounting section of the pipe to such a limit that the fitting pipe can be inserted into it. After the expansion of polyethylene, striving to take its original form, and this process passes more actively when the material is heated. The pipe is narrowing and tightly fitting the embossed fitting fitting.
• After the fitting is installed in the pipe, you need to press the sleeve for fitting. For this operation, you will have to make a certain effort, so a special tool is used to conduct it – the extensor. It can be manual or mechanical.

Pressing the sleeve with a unique instrument

• After the sleeve rises in its place, the assembly process is over.

Since every manufacturer uses a different set of "chips," the assembly options may vary. However, the basic idea is still the same as of this writing.

Joining by welding

This is how PE-RT pipes are connected using specialized equipment and fittings. It should be remembered that not every PE-RT pipe is intended to be connected in the same way. Consequently, this kind of subtlety needs to be explained by a store specialist before material is purchased.

After presenting the findings, it will be helpful to reiterate that money shouldn’t be saved arbitrarily and that pipes shouldn’t be chosen based solely on where they are going to be used or under what circumstances. Momentary success that is probably not that significant can turn into major problems and depressing, even disastrous, outcomes. Click the link to study basalt mineral wool.

You might be curious to know more about what a bimetallic radiator is.

Afanasyev Evgeny, Chief Editor

The publication’s author 03.02.2016

Plastic pipes are a particularly adaptable and effective choice when it comes to heating and insulating homes. Plastic pipes are an affordable option for heating systems due to their robust construction and lightweight nature. They require less labor and upkeep because they are simple to install and resistant to corrosion. Furthermore, plastic pipes have a high heat conductivity, which guarantees effective heat transfer throughout the system. They can be installed more easily in confined areas and around corners due to their flexibility, which makes them appropriate for a variety of architectural designs. In general, plastic pipes prove to be a sensible option for heating systems due to their dependability, affordability, and efficiency.

Did I enjoy the article? Save to avoid losing!

Video on the topic

Valfex pp-r pipe reinforced with fiberglass

Pipes for heating. What to choose?

How to choose polypropylene pipes | PP course | Part 2 | Test of four popular manufacturers