Sleeve welding of polypropylene pipes. How to weld (solder) polypropylene pipes

This article will talk about how to weld polypropylene pipes, what tools are used for this and how the welding process is performed.

Compound polypropylene pipes performed using diffusion welding, based on melting by heating the parts being joined to the desired temperature. Electricity is used to heat parts: first, the parts are heated to their melting point, after which they are pressed tightly together, this process is called fusion welding.

Important: the parts to be welded must have the same properties.

The welding process itself includes the following steps:

Heat up to 260° welding machine;

Important: 260° is the melting temperature of polypropylene fittings and pipes.

The pipe and fitting are heated to the same temperature;
Press the pipe and fitting against each other in the direction of the axis;
After a couple of seconds, the connection can be considered completed, resulting in a homogeneous material with a single structure.

Moreover, after welding it is impossible to find the location of the seam, since during the welding process the parts melted and their structures merged, that is, a homogeneous single part was obtained, which allows melting to guarantee a strong and high-quality connection of the parts.

Tools for welding polypropylene pipes

For welding polypropylene pipes used in water supply (hot and cold) and heating systems, it is enough to use standard set tools, including:

Myself ;
Heating nozzles;
Roulette;
Scissors;
Bolts with which the attachments are attached to the welding machine;
Level;
Hole template;
Hexagon.

The welding machine, whose power can reach 1500 W, operates from electrical network 220 V. The light weight of the device makes it easy to transport, and the comfortable handle allows you to connect pipes in different positions.

In addition, the device is equipped with a switch and a temperature regulator that allows you to maintain a constant temperature of 260°. When the device is turned on, a red indicator lights up on it, which goes out after receiving desired temperature and you can use the device.

Nozzles

The most important element of the welding machine are welding nozzles, designed to heat the outer and inner surfaces of the parts to be joined.
IN standard set The welding machine usually has nozzles with a diameter of 16-40 mm.

Important: nozzles for connecting larger diameter pipes (up to 125 mm) are purchased separately in hardware stores.

The Teflon shell allows you to protect the nozzle from the effects of molten plastic, as well as reduce the impact on the plastic being welded from the heating element, improving the quality of welding.

In addition, the Teflon coating prevents molten plastic from sticking to the device.

Important: it is necessary to constantly monitor the cleanliness of the Teflon coating.

Welding attachments consist of two parts:

A polypropylene pipe is inserted into the part with holes;
A fitting is placed on a part that has a protruding collar.

As a result, uniform heating occurs up to 260° as outside pipes and inside fitting made of polypropylene. The attachment is secured to the welding machine using the bolts supplied with the machine.

Important: during operation of the device, the bolts may become loose; in this case, they must be tightened.

The bolts securing the attachments to the device are tightened using the supplied cylindrical screwdriver (sometimes a hexagon). The installation of nozzles should be carried out before heating begins, and replacing nozzles while heating is allowed only in extreme cases.

Cutting pipes before welding

For cutting polypropylene pipes with a diameter of no more than 32 mm before welding, scissors are used, the blades of which are made of steel High Quality. These scissors are provided with a 1-year warranty with the condition that they will only be used when cutting polypropylene pipes.

Important: there are also scissors on sale that allow you to cut pipes with a diameter of up to 63 mm, and cutting pipes with larger diameters is usually done using a metal hacksaw.

Instructions for welding polypropylene pipes

First of all, let’s take a closer look at the main stages of preparing the machine for welding polypropylene pipes:

Turn on the welding machine, two indicators light up on it:

Device power-on indicator;
Thermostat indicator.

Until the indicators go out, the welding machine heats up, which usually lasts about 10-12 minutes. Turning off the second indicator signals that the device has heated to the required temperature.
After the first turn on, the device consumes more energy, which leads to heating of the nozzles to a temperature of about 300-320°, which causes deformation of the plastic during welding.
Therefore, first wait until the heating indicator is reactivated and turns off, after which you can begin the process.

Welding is performed as follows:

A polypropylene pipe is placed in the hole on one side of the nozzle;
The fitting fits onto the protrusion on the other side;

Important: when putting on the fitting, apply slight pressure.

The pipe and fitting are held in this position for the time required for heating, connecting the parts and cooling them.

The time required for heating, joining and cooling depends on the diameter of the PP pipe and the depth of welding. Recommended values for these time periods are given in the table:

Welding depth	Pipe diameter,	Heating time	Connection time	Cooling time

When welding polypropylene pipes, the following nuances must be taken into account:

The welded joint will be the most reliable and of high quality only if the heating time is strictly observed;
Heating for too long causes severe melting of the polypropylene and deformation of parts;
Heating for a time shorter than that indicated in the table leads to insufficient melting of the parts, which will cause joint leaks during operation.

When welding polypropylene pipes, it is prohibited:

Move parts in the direction of the axis;
Immediately after connecting the parts, try to correct their location, which reduces the flow area at the junction;
Change the shape of the pipe by bending during the cooling process.

That's all I wanted to tell you about how to cook polypropylene pipes. There is nothing particularly complicated in this procedure, the main thing is to prepare necessary tool and perform welding in accordance with the instructions, accurately maintaining the connection time.

1 Scope and regulatory framework

Pipes made of polypropylene (more precisely, random copolymer of propylene, or PP-R) are very popular for installing plumbing (hot and cold water supply inside buildings) and heating systems. Such pipes are connected using the “socket welding” method.

The popular name of the method is “socket” welding of polypropylene pipes, or “socket” welding (or, as in old standards, “socket welding”). Because the direct connection two pipes are made using a fitting called a coupling; another popular name for the method is “socket” welding plastic pipes.

A popular name for the equipment is “apparatus” for socket (socket) welding of polypropylene pipes. Jargon for hand-held devices is a “soldering iron” for plastic pipes. The latter, although fundamentally wrong, has taken root.

The workable socket welding technology is currently (February, 2015) regulated only by the German DVS standards: socket welding of polyethylene pipes - DVS 2207-1; technology for welding polypropylene pipes - DVS 2207-11; socket welding of PVDF pipes - DVS 2207-15. The listed standards suggest detailed instructions on pipe welding, from preparation to technological modes.
And that’s it, no other standards. And no other materials. It makes sense to talk separately about PVC. PVC is a hard material and subject to thermal degradation when heated. PVC pipes of small diameters are glued into a socket with special glue. Basically, pressure PVC pipes s can be welded, but only by butt welding. And the definition of “soldering iron for PVC pipes” was born and supported by people who do not make a difference between PP and PVC. Well, don’t worry, let there be a soldering iron for PVC pipes, the sales manager understands that we are talking about a socket welding machine.

The design of the apparatus and the specifications of the hottest tool for socket welding are regulated only by the German DVS standards, namely DVS 2208-1.

In our country, the development and ratification of a comprehensive normative document on socket welding of pipes with a heated tool is planned for 2016. It is just not yet known whether it will be GOST or STO, etc. The document, to a first approximation, is already ready and includes both the design of the apparatus and a replaceable heated tool for socket welding of pipes, as well as instructions for welding polypropylene , polyethylene and PVDF pipes. Welding modes are presented in the form of temperature and time tables. The document does NOT include instructions for designing and installing a plumbing or heating system; this is a separate topic.

Despite the lack of a legitimate description of the technology and equipment, socket welding has long been recommended for various pipelines by certain standards of the Russian Federation:

SNiP 3.05.04-85* (external water supply and sewerage) suggests connecting polyethylene pipes and fittings using “butt or socket welding” (clause 3.58. SNiP). The document does not indicate the limitations of the method or even its essence. Pipes made from other thermoplastics are not mentioned, which is understandable since the document only deals with external piping.
SP 40-102-2000 (installation of water supply and sewerage from polymer pipes) proposes to connect polyethylene, polypropylene and polybutene pipes “by socket welding” (clause 3.3.1 SP). Socket welding is recommended “for pipes with an outer diameter of up to 110 mm and walls of any thickness” (clause 7.3.2 SP). A stylistic error in the quotation (if anyone noticed) does not count. But regarding walls of any thickness, this is a fundamental mistake. The author once personally spent time selecting the welding mode for thin-wall pipes. It turned out that welding is possible only with rapid heating of the surfaces to be welded with a heated tool at a temperature of 280-290ºC. But at this temperature, any Teflon coating on a heated tool is destroyed quite quickly. And if the temperature of the tool is 260ºC, melting of the surfaces takes longer, then the pipe has time to warm up through and loses the necessary elasticity. By the way, there are no welding instructions or a table of modes in the joint venture.
VSN 003-88 Ministry of Oil and Gas Construction (PE and PP oil pipelines) proposes to connect PE and PP pipes by “resistance welding with a heated tool, butt or socket” (clause 7.5.3.1. VSN). It even shows the technology for welding polypropylene pipes in the form of a table of welding times depending on the wall thickness - heating time, technological pause and fixation. And it’s even given completely modern requirement to the temperature of the heated instrument - 260±10°C. VSN 003-88 is a highly respected document, if only because it is one of the first in the USSR (namely, the second after OST 6-19-505-79) document offering a clear and workable technology for butt welding of pipes. However, the table for socket welding of polypropylene pipes is ineffective here, if only because it suggests heating pipes with a wall thickness of less than 3 mm for 3-8 seconds.

Practice-justified restrictions on the use of socket welding are offered only by DVS standards: diameters 16-125 mm with a lower limit on the thickness of the pipe wall (see paragraph 2, Table 1).

In practice, socket welding technology is used in the vast majority of cases when installing water supply and heating systems from polypropylene pipes. Conversely, when installing water supply and heating systems from polypropylene pipes, in the vast majority of cases, socket (socket) welding technology is used. Thus, “polypropylene pipe welding technology” and “socket welding technology” are practically synonymous. This is due to a set of complementary circumstances:

Among all the methods of welding plastics, socket welding of pipes is the easiest to do with your own hands, at home. There are only two limitations: (1) socket welding does not work on thin-walled pipes; (2) with increasing diameter, socket welding becomes technically complex and economically impractical. Those. This best method welding for thick-walled pipes of small diameters.
For plumbing and heating systems inside buildings, small diameter pipes made of heat-resistant material are required.
Intra-house pipelines involve many bends and branches, which are organized by connecting parts - fittings.
Polypropylene has a low price; only polyethylene, which is not heat-resistant, is cheaper than it. Polypropylene is quite heat-resistant, although it is inferior to expensive polybutene or even more expensive PVDF.
At temperatures of 70-80°C, polypropylene pipes have sufficient long-term strength only at large thickness walls. This thickness is quite sufficient for socket welding.

Socket welding of polyethylene pipes technically has no contraindications. But the problem is that polyethylene pipes tend to have a higher SDR. In other words, polyethylene pipes of the diameters that are suitable for socket welding usually have too thin a wall. In addition, due to the low price and low heat resistance of polyethylene, the main use of polyethylene pipes is external underground water pipes or gas pipelines, and these are already large diameters. Those. The diameter and wall thickness of polyethylene pipes are usually unsuitable for socket welding.

This pipeline installation technology for various purposes, like welding polypropylene pipes, has become a real find for many amateur craftsmen.

Polypropylene pipes are used in the installation of water supply, heating and sewerage communications.

Those who chose this method for installing water supply, heating and sewerage communications ceased to be dependent on the services of welders, which were quite expensive.

Advantages and disadvantages of PP

Polypropylene pipes have a number of advantages, including:

long service life;
no corrosion;
small weight;
ease of installation, which can be handled by a person who is not qualified as an electric and gas welder.

The disadvantages of PP pipes include:

lower strength compared to steel pipelines;
high coefficient thermal expansion;
destruction of material under the influence of ultraviolet radiation.

For pipelines with cold water the issue of thermal expansion is not as relevant as for hot water pipes and heating systems, however, with the start of production of PP products, foil reinforced or fiberglass, the problem of sagging heated water pipes can be considered closed. As for strength, it is better to place plastic pipes under the cladding. In the same way, they should be protected from sunlight.

If you decide, after weighing all the advantages and disadvantages of polypropylene pipes, to build a pipeline out of them with your own hands, then recommendations on how plastic pipes should be welded will certainly be useful to you.

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Which pipes to use

It should be said right away about the most popular polypropylene tubes in the construction of pipeline systems. Among them:

pipes with a cross section of 32 mm (they are used in risers and supply pipelines);
products with a diameter of 25 mm (used for installation of risers, floor wiring, installation of heating systems)
pipes with a diameter of 20 mm (connection of water supply and heating system).

It must be recalled that for transporting hot water, reinforced pipes should be used, whose coefficient of thermal expansion is 0.03, and for cold water you can use cheaper products without a reinforcing layer (their expansion coefficient is 0.15).

Nevertheless, the change in the linear dimensions of a pipeline, even reinforced with aluminum foil or fiberglass, over a section 5 m long can be 15 mm (what can we say about unreinforced pipes, the length of which increases by 1.5 cm per linear meter when heated to 90°C) .

This factor should be taken into account when designing a heating or plumbing system. To avoid stress in the pipeline, in its straight sections longer than 5 m it is necessary to install not rigid, but only pipe-supporting fasteners. In addition, compensators should be installed on such runs. They can be made in a U-shape or in the form of a loop.

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Types of welding of PP pipes

Scheme of butt welding of PP pipes.

Additional turns of the line will require the use of fittings, and welding plastic pipes will help to connect them and pipes into a single system. There are 2 types of it.

Fitting welding.

As for the latter, it is used in the assembly of pipelines with a diameter of 50 mm or more and a pipe wall thickness of 4 mm or more. This method will be discussed later. It should be noted that such a pipeline is rarely installed at home, since it requires rather expensive specialized equipment. This technology is mainly used for construction main water pipelines, including waste.

Fitting welding has become more widespread, which can be easily done with your own hands by purchasing or borrowing a device for soldering polypropylene pipes.

This welding machine (in other words, an iron or soldering iron) does an excellent job of connecting pipelines of the most popular diameters in the construction of individual water supply and heating systems.

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Fitting welding technology

To weld polypropylene pipes, fittings are required.

The technology for welding PP pipes is based on physical properties polypropylene, which melts when heated to 175°C, but is able to restore its strength when cooled, which occurs in a matter of minutes.

When welding, both the end of the tube and the fitting heat up and melt. When joined in a hot state, they are soldered together and, upon cooling, turn into an almost monolithic connection.

Welding of the pipeline is carried out with a special soldering iron, but in the work you still need to use:

marking tool;
hacksaw for metal;
construction knife.

However, with the help of a hacksaw and a knife it is difficult, although possible, to achieve high-quality processing end edges of the tubes, so for cutting it is better to use a pipe cutter, as well as a shaver, which is used to clean the internal cavities of reinforced tubes before welding.

Since during welding the tubes are driven into fittings, when calculating the length of the pipeline system, it should be taken into account that each tube will be buried in them by 14-22 mm (depending on the diameter of the pipes and fitting) from each end. When making calculations, you need to add the calculation result to the total length of the pipeline (for example, 15 mm x 2K, where K is the number of welded joints).

The “iron” is equipped with special nozzles in which tubes and fittings of corresponding diameters are simultaneously heated. The heating temperature is 260°C. As soon as the polypropylene becomes sufficiently plastic, the pipeline elements are connected and held for some time with some force. When fixing assembled parts, loads that deviate away from the axis of the assembly are not allowed.

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Errors when welding water pipes

In addition to various distortions, which will lead to insufficient tightness of the seams, the home craftsman may make several more mistakes when assembling the water pipeline.

Dirty or damp tubes are installed: dirt will cause lack of penetration, and water evaporating when heated will deform the connection or form “sinks” in it. To avoid such troubles, the tubes should be additionally cleaned immediately before welding.
The cavity of the reinforced PP tube to be heated is poorly cleaned of aluminum foil: it is necessary to check the quality of cleaning of the walls.
Polypropylene remains on the soldering iron nozzles after welding the previous section - in this case, the remaining plastic must be removed, but only wooden tools or a cloth can be used to remove it, so as not to damage the Teflon layer. Cleaning of attachments should be carried out on a slightly warm instrument.
Using low-quality material for welding - you should buy PP pipes only from reputable sellers. Unjustifiably cheap products should arouse suspicion.
The reason for poor quality welding is the use of pipes made by different companies. They may have different chemical compositions, so their heating and cooling times, as well as their degree of softening and ability to diffuse, may vary. For each circuit it is better to purchase products from one manufacturer. It is advisable to purchase all elements of the water pipeline in one batch.
Poor quality installation of the pipeline - distortions have already been written about, but the tightness of the connections has a detrimental effect:

insufficient penetration of the workpiece into the fitting;
poor heating of the elements (there will be no reliable soldering of them) or delay in connecting the pipes, which will lead to the plastic hardening even before they are assembled;
overheating, which can cause sludge to form, impairing the permeability of the collector;

To ensure high-quality welding of plastic pipes, you should use the data in the following table.

It shows that heated PP tubes need to be connected as quickly as possible, and they should be pressed against each other for the time specified in the “Welding time” section. In addition, home craftsmen who decide to assemble the pipeline themselves can be advised to weld the line even before assembling it in a place where it would be inconvenient to do this. Therefore, a detailed diagram indicating exact dimensions all sections of the pipeline and its configuration.

Any modern housing, be it a private mansion or a city apartment, must be equipped with a variety of engineering communications. And if so, then either during the construction process, or during repairs or reconstruction, sooner or later the owners will have to face the problem of installing or replacing pipes and a heating system. Few people are now seduced by the labor-intensive and rather complex installation of steel VGP pipes. They are expensive in themselves, require considerable additional costs for transportation, and their processing and connection are associated with specific operations that not everyone can do - cutting, bending, electric or gas welding, thread cutting, etc. Plus, a special approach is required to “packing” each threaded connection so that the connecting unit turns out to be of high quality, without leaks.

It’s good that modern technologies make it possible to avoid all this hassle by using polypropylene pipes. At making the right choice materials and high-quality installation, plumbing and heating circuits are practically in no way inferior to steel ones, and in many respects they are far superior to them. In addition, the soldering of polypropylene pipes itself is not so complicated; instructions for its implementation will be discussed in this publication.

Not all polypropylene pipes are the same

Before you start considering the installation instructions for polypropylene pipes, it makes sense to give at least general concept about this material, in particular about its varieties and areas of application. Choosing pipes based on the principles of “which ones are cheaper” or “which ones were available” is completely unacceptable. The consequences for an unscrupulous home craftsman can be very sad - from deformation of the laid pipeline to its rupture or the appearance of leaks in connecting nodes.

There is no need to explain the difference in diameter - in different systems and in their different sections their sizes are used, which are predetermined by hydraulic calculations. The range of diameters, from 16 to 110 mm, allows you to almost completely provide everything possible options. Moreover, practice shows that for a house or apartment, an assortment of up to 40 mm is usually sufficient, much less often – up to 50 ÷ 63 mm. Larger diameter pipes are, rather, main pipes, and they have specific features installation, but face it home handyman- it’s unlikely that you’ll have to.

The difference in color between some types of pipes may immediately be apparent. This is what you should pay least attention to - white, green, grayish and other walls - they don’t say anything. Apparently, this is simply a decision by manufacturers to somehow distinguish their products from the general background. By the way, for heating circuits White color will definitely be preferable, since the pipeline will unobtrusively fit into any interior without creating a disharmonious color “spot”.

But colored stripes, if they exist, already carry an informative load that is intuitively understandable to everyone. The blue stripe means the pipe is designed exclusively for cold water supply, the red stripe means it can withstand elevated temperatures. However, even this color coding(which, by the way, very often does not exist at all), is only very approximate and does not fully reveal the operational capabilities of a particular pipe. It helps you simply not to make mistakes during the installation of the system. By the way, the longitudinal line is also good because it becomes a good guide when joining mating parts during soldering.

Much more information is provided by alphanumeric markings, which are usually printed on the outer wall. This is where it’s worth being more careful.

The international abbreviation for polypropylene is PPR. There are several types of material, and you can find the designations PPRC, PP-N, PP-B, PP-3 and others. But in order not to completely confuse the consumer, there is a clearer gradation of pipes - by type, depending on the permissible pressure of the pumped liquid and its temperature. There are four such types in total: PN-10, PN-16, PN-20, PN-25. In order not to talk at length about each of them, you can give a sign that characterizes operational capabilities and areas of application of pipes.

polypropylene pipes

Type of polypropylene pipes	Working pressure (nominal)		Pipe Applications
	MPa	technical atmospheres, bar
PN-10	1.0	10.2	Cold water supply. As an exception - supply lines to the circuits of the water-heated floor, with a maximum operating coolant temperature of up to 45 °C. The material is the most affordable - due to its not particularly outstanding physical, technical and operational parameters.
PN-16	1.6	16.3	The most popular option for autonomous cold and hot water supply systems, with an operating temperature of no more than 60˚C, a pressure of no higher than 1.6 MPa.
PN-20	2.0	20.4	Cold and hot autonomous or central water supply. Can be used in autonomous systems heating, where there is guaranteed to be no water hammer. The coolant temperature should not exceed 80 ˚С.
PN-25	2.5	25.5	Hot centralized water supply, heating systems with coolant temperatures up to 90÷95˚С, including central ones. The most durable, but also the most expensive type of pipe.

Of course, in order for the pipe to withstand high blood pressure and temperature, it should have thicker walls. The value of the wall thickness and, accordingly, the nominal diameter of polypropylene pipes of various types is in the table below:

Pipe outer diameter, mm	Type of polypropylene pipes
	PN-10		PN-16		PN-20		PN-25
	Passage diameter, mm	Wall thickness, mm	Passage diameter, mm	Wall thickness, mm	Passage diameter, mm	Wall thickness, mm	Passage diameter, mm	Wall thickness, mm
16	-	-	11.6	2.2	10.6	2.7	-	-
20	16.2	1.9	14.4	2.8	13.2	3.4	13.2	3.4
25	20.5	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	-	-

With all the advantages of polypropylene, it also has a rather significant drawback - very significant linear expansion when heated. If for cold pipelines located inside a building this is not so significant, then for hot water supply pipes or heating circuits this feature can lead to sagging, sagging of long sections, deformation of complex junctions, and the occurrence of internal stresses in the body of the pipe, shortening its service life.

To minimize the effect of thermal expansion, pipe reinforcement is used. It can be aluminum or fiberglass.

The fiberglass reinforcing belt is always located approximately in the center of the pipe wall thickness, and does not in any way affect the soldering technology.

But with aluminum it’s a little more complicated. There are two types of such reinforcement. In one case, the foil layer is located in close proximity to the outer wall of the pipe (in the illustration - bottom left). Another option is that the reinforcing belt runs approximately in the center of the wall. For each type of such reinforcement there are special technological nuances installation, which will be discussed below.

Both fiberglass and aluminum reinforcement significantly reduce the thermal linear expansion of polypropylene pipes. In addition, the aluminum layer performs another function: it becomes a barrier against oxygen diffusion - the penetration of oxygen molecules from the air through the walls of the pipe into the coolant.

The penetration of oxygen into the liquid coolant medium can cause a number of negative consequences, among which the main ones are increased gas formation and activation of corrosion processes, which is especially dangerous for metal parts of boiler equipment. The reinforcing layer can greatly reduce this effect, which is why such pipes are most often used specifically for heating circuits. In plumbing systems, it is quite possible to get by with fiberglass reinforcement, which does not have a significant effect on diffusion.

Types of polypropylene pipes	Designation	Thermal expansion coefficient, m×10 ⁻⁴ /˚С	Oxygen diffusion indicators, mg/m²× 24 hours
Single layer pipes:
	PPR	1.8	900
Multilayer pipes:
Polypropylene, glass fiber reinforced.	PPR-GF-PPR	0.35	900
Polypropylene, reinforced with aluminum.	PPR-AL-PPR	0.26	0

The illustration below shows an example of marking a polypropylene pipe:

1 – in the first place is usually the name of the manufacturer, the name of the pipe model or its article number.

2 – material of manufacture and structure of the pipe. IN in this case– This is a single-layer polypropylene. Pipes with fiberglass reinforcement are usually marked PPR-FG-PPR, with aluminum – PPR-AL-PPR.

Reinforced pipes with an outer polypropylene layer and an inner wall made of cross-linked polyethylene may be found. They will have a designation such as PPR-AL-PEX or PPR-AL-PERT. This does not affect the soldering technology, since inner layer does not take part in it.

3 – standard pipe dimensional coefficient, equal to the ratio of the outer diameter to the wall thickness.

4 – nominal values of outer diameter and wall thickness.

5 – the type of pipe mentioned above according to the nominal operating pressure.

6 – list international standards, to which the product corresponds.

Pipes are usually sold in standard lengths of 4 or 2 meters. Most retail outlets practice selling with cuts in multiples of 1 meter.

Numerous components are available for sale for all pipes - threaded fittings for transition to another type of pipe, with external or internal threads or with an American union nut, couplings, tees, diameter transitions, bends at 90 and 45 degree angles, plugs, bypass loops , compensators and other necessary parts. In addition, it is possible to purchase taps, valves, manifolds, and “oblique” coarse water filters designed for direct soldering into polypropylene pipework.

In short, such diversity allows you to choose the most convenient diagram assembling a system of almost any degree of complexity. The cost of most of these parts is very low, which allows you to purchase them with a certain reserve, at least so that before starting practical installation conduct a short training session - “get your teeth in”, so to speak.

Methods for connecting polypropylene pipes

Polypropylene is a thermoplastic polymer - when heated, its structure begins to soften, and when two fragments uniformly heated to a certain temperature are connected, mutual diffusion occurs, or rather, even polyfusion, that is, interpenetration of the material. When cooling, the properties of polypropylene do not change, and with a high-quality connection - ensuring optimal heating and the required degree of compression, after reverse polymerization there should be no boundary as such - a completely monolithic assembly is obtained.

It is on this property that the main technological methods for joining polypropylene pipes are based - this method is often called polyfusion welding.

Such welding (soldering) can be carried out using a socket or butt method.

Sleeve welding is precisely the technology that is most often used when installing water pipes or heating circuits in a house or apartment. It is designed for small and medium diameter pipes, up to 63 mm.

Its meaning is that any connecting unit involves the use of two parts - this is the pipe itself and the coupling, the internal diameter of which is slightly smaller than outside diameter pipes. That is, in a normal, “cold” form, the parts cannot be paired. A coupling can be not only, pardon the tautology, the coupling itself, but also the installation section of a tee, bend, tap, threaded fitting and other components.

The principle of such welding is shown in the diagrams below.

The pipe (item 1) and the coupling or any other connecting element (item 2) are simultaneously placed on the heating elements of the welding machine.

A pair is pre-installed coaxially on the working heater itself required diameter, consisting of a metal coupling (item 4), into which the pipe will be inserted, and a mandrel (item 5), onto which the necessary connecting element is placed.

During the heating period, a belt of molten polypropylene of approximately the same width and depth is formed along the outer surface of the pipe and the inner coupling (item 6). It is important to choose the right heating time so that the melting process does not penetrate the entire pipe wall.

Both parts are simultaneously removed from the heater and coaxially, with force, connected to each other. The melted plastic outer layer of polypropylene will allow the pipe to fit tightly into the coupling until it stops, the length of the heated section.

At this stage, the process of polyfusion, cooling and polymerization occurs. The result is a reliable connection, which, although shown in the diagram as a shaded area (item 7), in reality, if you look at the section, it is not visible at all - it is practically a monolithic wall.

Butt welding is performed slightly differently.

One of the main differences is that the parts that are joined must be the same in inner and outer diameter.

The first step is to fine-tune the ends to ensure they fit perfectly together.

The pipes are pressed on both sides against a trimmer - a rotating disk (pos. 2) with precisely aligned knives (pos. 3)

The pipes are again pressed towards the center, and at the ends, over the entire wall thickness, areas of polypropylene melting are formed (item 5).

And, by analogy with the previous case, as the weld cools, it polymerizes, creating a reliable connection between the two pipes.

The principle seems simple, but this is only at first glance. With this welding technology, precise alignment of the mating parts is of decisive importance. In addition, during sleeve welding, the required degree of compression of the mating molten sections is ensured to a greater extent by the difference in the diameters of the parts. In this case, a significant external force is required, directed strictly along the axis of the connected pipes. All these conditions can only be met when using a special, rather complex machine-type apparatus.

There are many machines for butt welding, but almost all of them have a powerful frame with guides and clamps for clamping pipes of various diameters - to ensure joint alignment, a removable or folding end cap and heater, a mechanism for creating the required compression - manual, hydraulic, electric, etc. .P.

This technology is used, as a rule, only by professionals when laying main pipes, and the likelihood of encountering it at the household level is almost zero.

There is also a “cold” welding method - using glue based on a strong organic solvent. The point is that when treated with this composition, the surface layers of the polymer soften. The parts can be connected in the desired position at this time, and since solvents are usually highly volatile, they evaporate quickly. then the reverse polymerization process begins quite quickly.

This technology is more suitable for polyvinyl chloride (PVC) pipes that do not have proper thermoplasticity. In addition, this type of connection method has, perhaps, more disadvantages and limitations in use than advantages, so it is not in particular demand, especially since there is a simple and accessible technology for sleeve polyfusion welding.

What is required for installation work

So, in the future we will consider exclusively socket polyfusion welding (soldering). To cope with this task yourself, you need to prepare a number of tools and accessories.

First of all, this is, of course, a machine for welding polypropylene pipes. Such a tool is not so expensive, and many zealous owners already have it in their home “arsenal”.

The welding machine must be supplied with coupling-mandrel kits of the required diameters. Most devices allow you to simultaneously place two, and sometimes three pairs of working nozzles on their heating element, which allows you to install a system that uses pipes of different diameters without interruptions for replacement.

If you don’t have your own device, and circumstances currently do not allow you to purchase one, then many stores practice short-term rental with a daily fee - you can take advantage of this opportunity.

If you decide to buy a machine for welding polypropylene pipes...

All welding machines are designed approximately the same and operate on a similar principle, but they also have certain differences in layout and functionality. Helpful information for those who have decided to make such a purchase, it is posted in an article on our portal, specifically dedicated.

In the text you may find the definition of a pipe soldering machine - but this is just a “play on words”. There is no difference between these concepts in this case.

To cut the pipe, special scissors are required. Moreover, they must be sharpened, with a working ratchet mechanism that ensures a smooth cut. The blade should not be jagged or bent.

Of course, you can cut the pipe with a hacksaw, just a metal blade, or even a grinder, but this is absolutely not a professional approach, since the required accuracy and evenness of the cut cannot be achieved with such tools.

machine for welding polypropylene pipes

It is necessary to prepare a marking tool - a tape measure, a ruler, a construction square, a marker or a pencil. To correctly place the pipes, you have to resort to a level.
If you plan to solder polypropylene pipes with aluminum reinforcement, then additional tools are required.

- if the pipe has external reinforcement, then you will need a shaver that will clean the aluminum layer at the place of penetration.

- if the aluminum reinforced layer is located deep in the thickness of the wall, then the pipe still requires preliminary preparation, but in this case a trimmer is already used.

A trimmer is often similar in appearance to a shaver, but there is a difference between them - it lies in the arrangement of the knives. With a shaver, the cut goes tangentially parallel to the axis of the pipe, and with a trimmer, as even their names make clear, the knife processes the end and removes a small chamfer.

Read a useful article, and also familiarize yourself with the varieties and selection criteria on our portal.

We will dwell on this point in more detail when considering pipe soldering technology.

Many people overlook this, but the welded sections of pipes and couplings must be cleaned of dirt, dust, moisture, and then degreased. This means you need to prepare a clean rag and an alcohol-containing solvent (for example, regular ethyl or isopropyl alcohol).

But you should not use solvents based on acetone, esters, or hydrocarbons, since polypropylene is not resistant to them, and the walls may melt

It is also necessary to take care of protecting your hands. They will have to work in close proximity to the heating element of the device, and getting a serious burn is as easy as shelling pears.

Suede work gloves are best suited for this task - they practically do not restrict movement, will not begin to smolder from contact with a hot heater, and will reliably protect your hands.

And one more important warning. Majority installation work very often it can be carried out not locally, but, for example, on a workbench in a workshop - some devices even have special brackets with clamps for secure fixation on the table. This is convenient in the sense that the assembled unit is then quickly installed, for example, in cramped and uncomfortable conditions of a bathtub or toilet.

In any case, wherever soldering is carried out, it is necessary to provide highly effective ventilation. When polypropylene is heated, a gas with a pungent odor is released. The smell is not the worst thing - with prolonged inhalation, serious intoxication can occur. Believe me, I tested it on my own skin. The author of these lines spent a day with a temperature of 39° after seven hours of work in a fairly spacious combined bathroom, with a ventilation vent that seemed to work well. Don't repeat the mistakes!

How to solder polypropylene pipes

General technological methods for welding polypropylene pipes

First of all, a novice master must have a clear idea of what he is going to mount. A detailed diagram-drawing must be prepared, with dimensions and specific details indicated - this same “document” will become the basis for the purchase required quantity pipes and components.
If conditions permit, for example, there is no finishing in the room where the installation will be carried out, then it is best to transfer the diagram directly to the walls - it will be more clear, and you can measure the required lengths of pipes literally on the spot.

The key to success is to try to complete the maximum possible number of knots in a comfortable working position, on a workbench. Working with a soldering machine directly on site, and even alone, without an assistant, is extremely difficult task, and it is very easy to make an error. It is clear that such operations cannot be completely avoided, but their number should be reduced to the possible minimum.

The soldering machine is getting ready for use. Working pairs - couplings and mandrels of the required diameters for operation - are put on its heater and tightened with a screw. If you plan to work with one type of pipe, then there is no need to be clever - put on one pair, as close as possible to the end of the heater.

There are welding machines with a cylindrical heating element - it has a slightly different fastening of the working elements, like a clamp. But figuring this out is not difficult.

It will be much more convenient to work if the device is rigidly fixed to work surface workbench. It’s great if the design provides a clamp-type screw for fastening to the edge of the tabletop. But even with a conventional device, you can try to come up with some kind of fixation. For example, if the surface allows, the legs of the stand are screwed to the workbench with self-tapping screws.

Even with the stand fixed, the device can “wiggle” in it - there will definitely be some play. Here, too, you can provide your own fastening - drill a hole and screw in a self-tapping screw. When you need a soldering iron for remote work, removing this mount is a matter of a few seconds.

The soldering iron is connected to the network. If it has temperature control, then it is set to approximately 260 °C - this is optimal temperature for working with polypropylene. You should not listen to anyone that for the 20th pipe you need 260 degrees, for the 25th - already 270, and so on - increasing. The temperature is the same, the heating time of the mating parts simply changes. In any case, those tables that the manufacturer provides in the product data sheet, and which will be posted below in this article, are designed for exactly this level of heating.
Usually the soldering iron has a light indicator. A lit red light indicates that the heating element is working. Green – the device has reached operating mode.

However, many models have their own display features. Some devices even have a digital display with temperature indication. In any case, the device will “let you know” that it has warmed up to the required level.

The mating parts are prepared for work - the required piece of pipe is cut off, the connecting element is selected according to the installation diagram.

Not many people do this, and yet the technology requires mandatory cleaning of the connection area from possible dirt and dust, and degreasing. In addition, even the slightest drops of water or wet surface– water vapor can get into the melt layer, create a porous structure there, and this connecting unit risks leaking sooner or later.
The next step is to mark the connection. On the pipe it is necessary to measure from the end and mark the length of the penetration belt with a pencil (marker). It is up to this mark that the pipe will be inserted into the heating coupling, and then into the connecting piece. Each diameter has its own value - it will be indicated in the table below.

The second mark is applied if the relative position of the mating parts is important. For example, on one side of a pipe section a 90° bend has already been welded, and on the other side it is necessary to mount, say, a tee, but so that its central channel is located at an angle to the bend relative to the axis. To do this, first accurately determine the position of the parts, and then apply a mark across the border, along both sides.

There won’t be much time spent choosing the correct position during soldering, and such a “trick” will help accurately position the mating parts.

The next step is directly soldering the connection. It, in turn, also includes several phases:

— From both sides, the pipe is simultaneously inserted into the soldering iron coupling, and the connecting element is put on the mandrel. The pipe must go up to the mark made, the connecting element - all the way.

— After the pipe and connecting element are inserted completely, the warm-up time begins. Each diameter has its own optimal period, which should be followed.

— Once the time has expired, both parts are removed from the heating elements. The master has literally a few seconds to give the parts the correct position and, of course, alignment, insert one into the other with force and bring it to the same mark. Light adjustments, without turning relative to the axis, are allowed only for one to two seconds.

— In this position, the parts must be held, without the slightest displacement, for deadline fixation.

— After this, the assembled unit should not experience any load during the established period of cooling and polymerization of polypropylene. And only then can it be considered ready

Now - about the main parameters that must be adhered to during installation. For ease of perception, they are summarized in a table:

The name of indicators	Pipe diameter, mm
	16	20	25	32	40	50	63
Length of the pipe section to be welded, mm	13	14	16	18	20	23	26
Heating time, seconds	5	5	7	8	12	12	24
Time for rearrangement and connection, seconds	4	4	4	6	6	6	8
Time to fix the connection, seconds	6	6	10	10	20	20	30
Time for cooling and polymerization of the unit, minutes	2	2	2	4	4	4	6
Notes: - If thin-walled pipes of type PN10 are welded, then the heating period of the pipe itself is halved, but the heating time of the connecting part remains the same as indicated in the table. - If work is carried out outdoors or in a cold room at a temperature below +5°C, then the warm-up period is increased by 50%.

There can be no question of reducing the set warm-up time (except for the case mentioned in the note to the table) - quality connection It won’t work, and the knot will definitely leak over time. But regarding some slight increase, the masters do not have a unified view. The motivation here is that pipes from different manufacturers may differ slightly in material, that is, harder or, conversely, soft polypropylene is found. But the masters have accumulated experience and precise knowledge of the material used, but for a beginner, the recommended indicators should still be taken as a basis.

Good advice - when buying pipes and components - take a small supply of the cheapest connecting elements and conduct an experiment - training. You can prepare a few pieces of pipe and perform test soldering.

With high-quality soldering, a neat collar about 1 mm high is created inside the connecting node around the circumference, which will not interfere with the free passage of water. A neat collar will also be formed on the outside, which will not spoil appearance connections.

pipe cutters

But overheating can already lead to a defective connection. When the parts are combined, molten polypropylene begins to be pressed inward, where a “skirt” is formed and hardens, largely covering the passage. The water pressure in such a water supply may be reduced, and in addition, such a defect often becomes a place for blockages to form over time.

Conducting such a practical lesson will help you accurately determine all soldering parameters and avoid mistakes.

Features of working with pipes with aluminum reinforcement

As mentioned above, there are two options here - the reinforcement layer is located near the surface of the pipe, or deep in the wall. Accordingly, the methods of preparing the pipe for welding also differ.

It is clear that the layer of aluminum located near the surface simply will not allow for complete heating and connection of the assembly. In addition, such pipes always have a slightly higher diameter and simply will not fit into either the heating coupling or the connecting element. This means that it is necessary to peel off this layer to “pure” polypropylene.

For this, a special tool is used - a shaver. A piece of pipe is inserted into it and they begin to turn - installed knives Carefully sequentially cut off the top polymer coating and the aluminum underneath.

Processing is carried out until the pipe stops at the bottom of the tool - the dimensions of the shaver are such that it will cut the foil exactly in the strip that is required for the welded joint at a given diameter, that is, you don’t even have to carry out the appropriate markings.

When soldering, the entire cleaned area must be heated and then completely inserted into the connecting piece. Leaving even a thin strip of protected pipe outside is prohibited.

If aluminum foil is hidden in the bottom of the material, then it would seem that it does not allow for high-quality soldering. But there is already another nuance here.

If the pipe is not protected at the end, then water passing under pressure will try to delaminate it and find a way out between the aluminum layer and the outer polypropylene sheath. Aluminum, in addition, can begin to corrode and lose its strength. The result of such delamination first becomes “blisters” on the pipe body, which then inevitably end in a major accident.

The solution is to create conditions such that during welding the end of the pipe and the aluminum layer are completely covered with molten polypropylene. And this can be achieved by processing special tool, which was mentioned above - a trimmer.

Outwardly, it may be similar to a shaver, but its knives are located differently - they precisely align the end, cut a chamfer and remove a thin, about 1.5 - 2 mm from the edge, strip of aluminum foil around the circumference. During heating and during the mating of parts, the created bead of molten polypropylene will completely cover the end of the pipe, and the assembly will receive the necessary reliability.

Pipes with fiberglass reinforcement do not have any installation features.

The soldering process, as stated, is best carried out on a comfortable, spacious work site, assembling ready-made water supply (heating circuit) units as much as possible, and only then installing and connecting them in place.

Working “next to the wall” is always more complex, time-consuming and nerve-wracking, since you have to hold a fairly heavy apparatus with one hand, while simultaneously providing heating to both mating parts. It is often almost impossible to make such a welded joint without an assistant. Therefore, it is worth reducing the number of such operations to a minimum.

But it is important to avoid mistakes. To connect the assembly, it is necessary to provide a certain degree of freedom to the mating parts - they need to be moved apart to install a welding machine between them (plus the heating pair also has a certain width), then carefully, without distortion, insert it into the mandrel and coupling, after warming up, ensure progressive removal and then connection. It is necessary to foresee this point in advance - whether the available play is enough to perform all these manipulations.

It happens that inexperienced craftsmen, having not foreseen this nuance, are faced with the fact that there is only one weld left, and there is no way to complete it. What to do?

The solution may be to weld a dismountable connecting pair into the cut pipe - a threaded fitting and a coupling with an American union nut. The connection turns out to be reliable, and soldering such elements even in such difficult circumstances is no longer difficult.

If at least some component during installation raises even the slightest doubt, without any regret it should be cut out and other parts welded. Believe me, it won’t take much time and won’t entail serious expenses. But if, over time, such a dubious area suddenly leaks, the consequences can be very sad.
The next group of errors has already been mentioned above - a violation of pipe soldering technology. This may include insufficient or excessive heating. The force applied to the parts during connection should be moderate. Compressing too hard will cause an inner “skirt” to form. No less dangerous is the insufficient application of force - the pipe does not enter the socket of the connecting part completely, it remains there small area with an increased diameter and a thinner wall - a potential breakthrough site!

Do not forget to clean the welded parts from dirt and grease. This may seem unimportant, but in practice there are quite a few cases where such neglect subsequently resulted in a weak connection and the formation of a leak.
It is very dangerous to try to change the position of parts during the setting and cooling of the connection. This may not appear outwardly, but microcracks appear in the connecting seam, which subsequently lead to accidents. If you don’t like the connected node, throw it away and make a new one, but don’t try to change it!
When stripping reinforced pipe There should not be even a tiny fragment of foil left on the cleaned area - this could become a potential site for a future leak.
One more recommendation. It is clear that the material must be of high quality - you should not chase cheapness, since you can lose a lot more, especially since even branded polypropylene pipes and components for them are not so expensive. But there are cases when, during the installation of high-quality pipes, carried out in strict compliance with the technology, the connecting nodes nevertheless began to fail over time. And the reason is simple - it was really used quality material, but from different manufacturers. Seemingly insignificant differences in chemical composition and the physical and technical characteristics of polypropylene gave such an unexpected result - full diffusion of melts was not achieved.

Therefore, one final piece of advice: use high-quality pipes from one manufacturer. It’s probably clear that all components should also be of the same brand.

At the end of the publication, there is an educational video about soldering polypropylene pipes:

Video: a master shares the secrets of high-quality soldering of polypropylene pipes

The ability to assemble pipelines yourself is a definite plus polypropylene products. Using convenient and lightweight material, you can build a sewer system yourself, repair and modernize the water supply system.

The main thing is to understand the specifics of connecting prefabricated elements to each other. Agree, this is an important part of the work, responsible for the tightness of the highway and its trouble-free operation.

We offer you detailed information about how polypropylene pipes are soldered, what equipment is used in the work, and also list the most common mistakes made by novice welders.

The information we offer will help you build trouble-free communications. For clarity, the article is supplemented with graphic applications and a video guide.

The soldering process is carried out due to the pronounced thermoplastic properties of the material. Polypropylene softens when heated - it acquires a state similar to plasticine.

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This is what a soldering iron (“iron”) for polypropylene pipes looks like. Simple electrical device, semi-automatic, thanks to which plastic soldering is done

The designs of soldering machines for butt welding are characterized by increased complexity. Typically, such equipment contains not only a heating element, but also a system for centering the parts being welded.

As a rule, direct welding equipment, like the technology itself, is rarely used in the domestic sphere. Priority of use is industry.

A more complex device, with the help of which precise alignment of the parts to be welded is carried out with the further process of heating and soldering. Used with direct welding technology

In addition to soldering irons, the master will also need:

scissors - ;
construction tape;
bench square;
shaver for pipes with reinforcement;
marker or pencil;
surface degreasing agent.

Since the work is performed on high-temperature equipment, you should definitely wear thick work gloves.

Polypropylene Welding Procedure

Important warning! Work on welding polymer materials must be carried out in conditions of good ventilation of the room. When polymers are heated and melted, toxic substances are released, which in a certain concentration have a serious impact on human health.

The procedure for welding polypropylene is simple, but it requires precision and accuracy in work. You should also avoid common mistakes, such as insufficient or excessive heating

The first thing you need to do is prepare for work:

Install blanks of the required diameter on the heater plateau.
Set the regulator to 260ºС.
Prepare the mating parts - mark, chamfer, degrease.
Turn on the soldering station.
Wait for the operating temperature to reach – the green indicator turns on.

Place the mating parts (pipe - coupling) on the soldering station blanks at the same time. In this case, the polypropylene pipe is inserted into the internal area of one blank, and the coupling (or socket of the shaped part) onto the outer surface of the other blank.

Typically, the ends of the pipe are inserted along the border of the previously marked line, and the coupling is pushed in until it stops. When keeping polypropylene parts on heated blanks, you should remember important nuance technology – holding time.

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Conclusions and useful video on the topic

There is always something to learn from professionals. You can see how to work with polypropylene in the following video:

Installing polymer pipelines by hot soldering is a convenient and popular technique. It is successfully used in the installation of communications, including at the household level.

People without extensive experience can use this welding method. The main thing is to correctly understand the technology and ensure its execution exactly. A technological equipment can be bought or rented.

Do you have experience soldering polypropylene pipes? Please share information with our readers. You can leave comments and ask questions on the topic in the form below.