Polypropylene pipes with fiberglass for water heating. How to choose reinforced polypropylene pipes for heating

Polypropylene pipes reinforced with fiberglass appeared later than analogues with aluminum foil. But they rapidly began to gain popularity in the field of plumbing during the installation of water supply and heating systems.

The technical standards of this type of equipment are in many ways superior to non-reinforced PP pipes and successfully compete with aluminum-reinforced ones.

Glass fiber reinforced polypropylene pipes are marked PPR-FB-PPR or PPR/PPR-GF/PPR, where the marking FB (fiber fiber) and GF - glass fiber means the presence of fiberglass, and PPR is a brand of universal polypropylene, successfully used in heating and hot water systems.

According to the marking, the pipes are three-layer products: polypropylene - glass fiber - polypropylene.

But due to the fact that they are produced using co-extrusion technology (combining jets of different materials into a single integral structure almost at the molecular level), layers are not glued, as, for example, with aluminum reinforcement.

That is, with their multilayer the equipment is homogeneous and does not have the ability to delaminate.

Plastic glues together the fibers of glass, or fiber, located in the center, and subsequently it is they who do not allow deformation of sufficiently soft polypropylene.

Due to this design, reinforced with fiberglass PP pipes are tougher than simple ones. This somewhat complicates the installation procedure, but reduces the risk of sagging and allows the use of samples of a smaller diameter for heating and plumbing systems.

Another nuance - the rigidity of the inner layer contributes significant reduction in linear expansion characteristics for polypropylene pipes reinforced with fiberglass. This is one of the reasons why fiberglass reinforced PP pipes are used in heating systems.

The thickness and amount of the reinforcing composition is calculated in accordance with GOST standards. Fiberglass elements do not penetrate either the outer layer, where they would interfere with welding joints, or the inner layer, which would lead to a violation of sanitary standards. The absence of metal eliminates the appearance of hardness salts– means, all connections become literally monolithic.

In the manufacture of fiberglass, they are dyed in different colors, but they are not an indicator of any operational or technical characteristics. In terms of standard sizes, they correspond to other types of reinforced PP pipes., which allows the use of standard fittings and the replacement of individual sections of pipelines from the material of the old sample.

Advantages and disadvantages

Of the design flaws of fiber-reinforced propylene pipes, it can only be noted that, compared with models reinforced with aluminum, their expansion coefficient is slightly higher - by 5-6%.

But compared to non-reinforced, it is three times lower, by 75%, which allows you to increase the distance between the fasteners and reduce the cost of installation. As well as:

They are much thinner than non-reinforced PP pipes, which is very important when they are carried in walls, while the conductivity of the coolant is higher by 20%.
A layer of fiberglass will not allow the pipeline to break through, which ensures wear resistance and increased durability - up to 50 years.
The strength and tightness of the joints does not require regular maintenance.
Due to good insulating properties no condensation and heat loss is minimal.
The slight thermal expansion minimizes the risk of damage.
In addition, during installation, they do not require calibration and stripping, which is necessary for pipes reinforced with aluminum foil.
The thermal conductivity corresponds to that of conventional PP pipes and is lower than that of aluminum reinforced pipes.
Cases of delamination of AL polypropylene products are known, which is excluded during coextrusion with glass fiber.
All materials are non-toxic and completely harmless.
Light weight, easy to install. They are connected in any way - socket or butt soldering, threaded or flanged connection.
Chemical resistance allows you to withstand even low-quality coolant.
High permeability due to the smooth inner surface, respectively, and the absence of deposits.
Pipes flexible, abrasion-resistant and quiet, are pressure resistant.
Withstand temperature values in the range of -10 - +95 Celsius.
When reaching and even exceeding critical levels FB pipe may expand and sag, but will not burst.

True, some people are concerned about the possibility of fiber particles getting into the water. To avoid such a possibility, pipes can be treated with a trimmer - this will eliminate the contact of the reinforcing layer with water.

Criterias of choice

Looking at the marking of the pipe, you can immediately understand for what purposes it is intended, since the abbreviation PN means "nominal pressure", and the numbers - its working indicator.

PN-10 with a wall of 1.9 - 10 mm - are designed for temperatures up to 45 degrees, that is, they are applicable only in systems. Thin-walled, withstand pressure up to 1 MPa or 10 atm. Can be used for arrangement, but taking into account the temperature regime. Diameter inside and outside - 16.2 - 90 mm, 20 - 110 mm.

PN-20 with a wall of 16 - 18.4 mm are the most in demand, as they are almost universal. Suitable for cold water supply, heating, floor heating equipment. Withstand up to 95 Celsius and a pressure of 20 atmospheres. They have excellent throughput used in private and comfortable homes, public institutions, enterprises. Diameter inside and outside - 10.6 - 73.2 mm, 16 - 110 mm.

PN-25 with a wall of 4 - 13.3 mm - designed for arranging risers, heating and water supply systems, warm floors, for industrial purposes. Working pressure - 25 atmospheres, temperature - 95 degrees. Not subject to thermal deformation. Diameter inside and outside - 13.2 - 50 mm, 21.2 - 77.9 mm.

When choosing polypropylene pipes reinforced with fiberglass for mounting a heating system you need to build on your own requirements and product specifications:

Indications of the maximum temperature;
Rated pressure;
Diameter.

Accordingly, the most suitable polypropylene pipes with fiberglass for heating are PN-20 and PN-25 with d 16 - 40 mm, for warm floors - all three types. For making connections to radiators, models with a diameter of 20 to 24 mm are optimal. When installing smaller pipes, the internal seam formed during soldering can become an obstacle to the free flow of water.

For risers, samples with a size of at least 32 mm should be selected, otherwise the inner diameter will be small for full circulation. Pipes with d 40, due to their massiveness, are more often used for flush mounting.

Based on the above, we can conclude that a propylene pipeline with a GF layer - almost ideal option not only for sewerage or plumbing, but also for the heating system.

Besides fiberglass is an anti-diffusion barrier preventing oxygen from entering. Diffusion is fraught with acceleration of corrosion processes of all metal equipment - pumps, boilers, etc.

This happens especially quickly in water systems with high temperatures - hot water supply, heating.

Non-reinforced PP pipes cannot boast of such a property. According to many criteria, they are significantly inferior to fiber-reinforced ones, especially with regard to heating systems - polypropylene pipes without reinforcement are thicker, weaker, prone to deformation.

As you know, for arranging hot water pipelines or heating systems, the use of standard polypropylene or polyethylene pipes is impossible, since plastic is not able to withstand the required temperature load.

However, the use of more traditional products made of metals and alloys (copper, steel, etc.) is also undesirable - they are quite expensive and have too much weight, making installation and repair of the circuit difficult. In this case, a modern solution comes to the rescue - polypropylene pipes reinforced with glass fiber, combining the lightness of plastic and the reliability of alloys. It is the RVC pipe that has such characteristics.

Pros and cons of polypropylene products

Advantages of conventional polypropylene (PPR) pipes:

low cost - the price of such products is much less than products from metals and alloys;
strength;
light weight - polymer products are much lighter than similar metal products;
resistance to low temperatures;
chemical neutrality to most aggressive media - acids, alkalis, oil and gas products, salt solutions;
no risk of corrosion.

Disadvantages of simple pipes:

A small value of the upper temperature threshold - polypropylene pipes begin to melt when they reach 175 ° C, and soften already when the temperature in the system rises to 130-140 ° C. At first glance, this should not be a problem, since the operating temperature in the heat supply system is characterized by values of 90-95°C; however, when two parameters are combined - high pressure and high operating temperature - the damage received by the pipes from the coolant becomes more significant, therefore, the risk of damage to the pipes increases.
The tendency to expand significantly with increasing thermal load. To a greater extent, this applies to the length of products: the length of the pipes increases greatly, wavy lines appear on the surface. This is not only ugly, but also poses a threat of depressurization of the circuit or damage to wall or floor coverings, up to cracking of brittle materials - plaster or cement.

This problem is not solved by the usual methods, even the installation of compensators is not quite effective. The most logical solution is to use fiberglass reinforced plastic pipes. Characterized by all the positive properties of macromolecular compounds, and in addition by increased resistance to high temperatures, these pipes can be used in almost any heating circuits and hot water supply systems.

Comparison of pipes reinforced with fiberglass and aluminum foil

To strengthen plastic pipes and give them thermal stability, two types of reinforcement are used:

aluminum foil;
fiberglass.

In this case, an aluminum plate can be used in various versions: in perforated or solid form, act as an outer coating or be located in the middle of products, between polymer layers. Fiberglass is placed without fail inside reinforced plastic pipes.

It should also be noted that aluminum reinforcement allows the product to withstand more pressure within the system, so if the working pressure is not known or too high, this is the best option.

Characteristics of foil-reinforced pipes (designated PPR-AL-PPR):

increased rigidity of products, resistance to mechanical stress and all types of deformation;
thickness of the reinforcing metal layer - 0.1-0.5 mm (varies depending on the size of the pipe section);
the method of joining aluminum and plastic is glue, the quality of which determines the quality of products;
excellent tightness that does not decrease over time.

The installation of pipes with an aluminum layer is associated with some technological difficulties: before soldering or welding individual elements, the metal layer at the ends must be cleaned. Failure to comply with this recommendation will lead to a rapid loss of structural integrity - due, first of all, to the delamination of the polymer and metal during heat treatment, and secondly, due to electrochemical damage to aluminum.

Against the background of the problems listed above, polypropylene pipes with fiberglass look like a more acceptable solution:

the reinforcing material is similar in nature and characteristics to the base polymer;
before welding or soldering, there is no need to clean the ends;
during the heat treatment process, the glass fiber and the alloy not only do not delaminate, but, on the contrary, form a stronger connection.

Based on this, a fiberglass reinforced pipe is in most cases an ideal solution for the design of pipelines of various technological directions.

Characteristics of fiberglass reinforced products

As you might guess, such products have three layers: two polypropylene and one reinforcing, consisting of the same material mixed with fiber fibers (fiberglass). Due to the almost identical composition, such a three-layer structure is almost equivalent to a monolithic one.

Characteristics of glass fiber reinforced polypropylene pipes:

complete absence of the threat of corrosion;
remarkable smoothness of the inner surface of the products, which resists the accumulation of deposits and, as a result, the occurrence of blockages;
increased mechanical strength of products;
no threat of longitudinal or transverse deformation with an increase in the internal temperature of the system;
chemical and biological neutrality - both to aggressive environments and to waste products;
low hydraulic resistance, therefore, the value of pressure losses is reduced to a minimum;
good noise reduction;
do not affect the properties of the supplied water in any way, therefore, they are absolutely safe for human health;
long service life - with proper installation and operation - at least 50 years.

With regard to the dimensional characteristics of glass fiber reinforced pipes, the following diameters are most popular:

up to 17 mm - used for underfloor heating;
up to 20 mm - for domestic hot water pipes;
20-25 mm - such pipes with fiberglass are used for heating in common areas and when installing sewer risers.

To fix pipes of smaller diameter, plastic clips are enough; for products of large sections, clamps must be used.

Installation of pipes with fiberglass

The connection of such products is carried out in the same way as ordinary plastic pipes.

There are three ways to fasten products:

With threaded fittings.
With the use of cold welding (that is, special glue).
Thermal welding (soldering).

The first option is produced as follows: the end of the pipe is pulled onto the fitting of the connecting element and is crimped in a circle with a mounting nut. The connection in terms of reliability (strength and tightness) is not inferior to the third method, it is permissible to use it even when designing pressure-type pipelines. The only drawback is that with an immoderate application of effort when tightening the mounting nut, it can simply burst.

In the case of cold welding, the adhesive used ensures the speed of creating a joint, but not reliability. During installation, an adhesive composition is applied to the inner surface of the polypropylene coupling, then the end of the pipe to be connected is inserted there; the connection is held motionless for some time so that the glue has time to harden.

When welding using a welding machine, the surfaces of the ends of pipes and couplings are heated; after joining, they form a single polymer mass. Such a connection is the most durable and tight.

In general, the use of pipes reinforced with fiberglass is quite justified, convenient and profitable from an economic point of view.

Water supply, heating in a house or apartment (autonomous or centralized) is not complete without the use of pipes. Many people remember how unattractive metal pipes look, they need to be constantly painted, maintained, and still at any moment they can let the homeowner down, because over time they react to changes in temperature and pressure worse and worse.

The metal quickly becomes covered with scale from the inside, which significantly slows down the movement of hot water and, as a result, reduces heat transfer. Probably, all the disadvantages of metal pipes prompted scientists, engineers and technologists to develop and implement new models of pipes made from modern materials using advanced technologies.

Manufacturers of reinforced polypropylene pipes

It is no secret that when buying pipes, the choice of a manufacturer that has proven itself in the Russian and international markets is of considerable importance. Today we will introduce some popular brands specializing in such products.

FV Plast (Czech Republic)

The company specializes in polypropylene for heating, hot and cold water supply, heating. The company's products are available only in gray with an aluminum and fiberglass layer.

Metak (Russia)

The company manufactures various products from polypropylene, including pipes reinforced with fiberglass under the Metak Fiber brand. The company's products are ideal for heavily loaded heating systems.

Banninger (Germany)

The German company produces excellent products that are of the highest quality and reliability in operation. The buyer can easily find it in the shop windows by its emerald green color.

In conclusion, I would like to recommend our readers not to buy reinforced polypropylene from unknown companies that do not even indicate their brand name on the label. By saving a small amount when buying, you can lose much more money (nerves, time) when low-quality products let you down. And it usually happens at the most inopportune moment.

In order not to spoil everything with low-quality pipes when distributing the heating system, it is necessary to choose the “right” manufacturer and pipes of the corresponding category. There are a lot of manufacturers of polypropylene pipes in the world, but a unified marking system has not yet been developed and often products from the same material with similar characteristics have a different designation. However, some designations are standard, and knowing them will make it easier to select a material with the required technical characteristics.

Characteristics and marking of polypropylene pipes

To navigate the names and understand the difference, let's talk a little about grades of polypropylene. Any of them is indicated by two Latin letters: "PP" or in the Russian version "PP". Then there may be numbers or other letters that “mask” the types of materials:

It is PPR pipes (PPR in the Russian version) at this stage that are considered the best, safest and most reliable. Products PPR, PP-random can be used in centralized heating systems, as well as individual, if there is a gas or liquid fuel boiler. If a solid fuel boiler with automatic overheating protection is installed (it works at a coolant temperature of 95 ° C), a special polymer can be used for wiring the heating system, which has an increased temperature resistance: PPs. It normally tolerates an internal environment of 95 ° C and brief overheating up to 110 ° C.

If there is a solid fuel unit without automation in the system, no polypropylene will survive. Then for wiring you will need either copper or steel pipes. Polypropylene can be used in networks with such a boiler only if there are liquid heat accumulators, which smooth out temperature differences, increase system safety and reduce the cost of heating, while increasing its comfort.

The next thing to pay attention to is pressure. This parameter is marked in Latin letters PN, and the numbers behind them indicate the nominal water pressure that this pipe can withstand for 50 years at an ambient temperature of 20 ° C. They produce pipes PN 10, PN 16, PN 20 and PN 25. Accordingly these products will last 50 years at a pressure of 10, 16, 20 and 25 bar / cm 2 and an ambient temperature of 20 ° C.

Changes in temperature and/or pressure significantly shorten the service life. For example, the service life of products PN 16 at 50 ° C is no longer 50 years, but only 7-8. You also need to know that the greater the pressure, the thicker the pipe wall, although PN 20 and PN 25 have a reinforcement layer, which is why their walls and outer diameter are smaller than those of PN 16 counterparts.

In principle, PN 10, PN 16 brands can also be used for individual heating. They are suitable for coolant temperatures not higher than 70 ° C. Peak and for a short time can withstand heating up to 95 ° C. Their service life under such conditions, of course, is not 50 years, but they will work for ten years. As a positive aspect of such pipes, a lower cost can be noted (compared to PN 20 and PN 25). But there is a very significant drawback: a large expansion coefficient. Each meter of pipe, when heated to 70 ° C, increases by almost 1 cm. If such pipes are hidden in a wall or in a floor screed without a compensation circuit or loop, then after a while they will destroy nearby materials. If they are laid on top (fixed to the wall with clips / holders), then they will noticeably sag. If in a “cold” form such a pipeline looks normal and the eye does not linger on it, then hanging pipes significantly spoil the appearance. Therefore, such pipes are used more often for distributing cold or hot water (DHW temperature rarely exceeds 45-50 ° C and thermal expansion is not of such magnitude).

Reinforced polypropylene (PPR) pipe

For heating, reinforced polypropylene pipes are usually used (marking PN 20 and PN 25). Both types are suitable for both centralized and individual heating. These brands differ in the type of reinforcing material: fiberglass is used in PN 20, aluminum is used in PN 25 (solid sheet or perforated depends on the manufacturer). Despite the different materials of the reinforcing layer, both types have an expansion coefficient significantly lower than that of purely polymer pipes - ¾ less. But when using fiberglass, it is 5-7% higher than in foil products.

The best brands (Wain Ecoplastik, Valtec, Banninger, etc.) have a large number of fakes. In addition to the low price (compared to the original ones), fakes can be identified by eye. A quality pipe has even layers. This is the main indicator of quality. If the reinforcement is located in the middle, then both layers of polypropylene have exactly the same thickness in any place, although all of the above manufacturers have a layer of aluminum closer to the outer edge.

Another sign by which you can identify a fake: almost all market leaders use aluminum butt welding. Such pipes are more reliable, although their production requires expensive equipment. The photo above shows the seam "overlap". This is a clear sign of cheap pipes, and low, to put it mildly, quality.

The outer and inner surfaces of the original products are smooth. The inscription is applied clearly, exactly along the ruler, not smeared. In addition, in order to avoid claims in crafts, the name is often slightly distorted: an extra letter is omitted or added, another is replaced.

One of the EcoPlastik fakes. If you look closely, you will see a spelling error (click to enlarge)

So, just by looking closely at such “little things”, you can identify a fake. In general, if you have exactly decided on the brand, do not be too lazy to go to the official website and ask how the pipes of the selected brand should look, what the surface should be: matte or smooth, what color, what the logo that is applied looks like, study the range of products that it produces this firm.

Fiberglass reinforced pipes

In PN 20 pipes, fiberglass is used as a reinforcing material. In general, initially, this type was intended for supplying hot water. Of course, they will also feel good in most heating systems. And they will work well. Not 50 years old, but not a year or two either. Provided that these are really high-quality pipes, and not a fake. And now we come to the important point: how to define quality. Regrettably, you need to focus on the price: Europeans produce the best pipes. You can't argue here: experience. But their prices are high.

Now about the pipes themselves and their use in heating. In this type of products, neither the color of the reinforcing insert, nor the material from which it is made, play practically no role. Fiberglass can be orange, red, blue or green. This is just a coloring pigment and does not affect anything. If you can focus on color, then only on the longitudinal strip that is applied to the surface of the pipe: red indicates suitability for hot environments, blue for cold ones, both together - about versatility.

Now about the features of the use of fiberglass-reinforced pipes specifically for heating. They can be set, but with some reservations. This is due to the second disadvantage of polypropylene (except for a large thermal expansion) - high oxygen permeability. At high temperatures, a large amount of oxygen in the system leads to a fairly active destruction of metal-containing elements. If the system uses really reliable and high-quality aluminum radiators that comply with certificates (a prerequisite is from primary aluminum), then there should not be any big problems. But if their quality is in doubt, or cast-iron radiators are installed, then only pipes with foil should be used, which significantly reduces the amount of oxygen passing through the walls of the PPR pipes. And one more thing: the permeability depends on the wall thickness, but not much, but depends on the quality of the material. So we again returned to the fact that in order for heating from polypropylene pipes to work for a long time, quality is required.

But most of the installers advise installing pipes with fiberglass for heating. Why? Installing them is faster. Approximately twice. And all because in order to obtain a high-quality weld in foil pipes, it is necessary to remove the foil layer and part of the material that is above it. This requires a special device (each diameter has its own). As usual, a good tool is not cheap, and you don’t want to spend money on it at all. In addition, the stripping procedure itself in total lengthens the installation procedure of the system by almost two times. And skill in this matter is also needed. Actually, their reasons are clear. But if you are doing heating for yourself, then they are unlikely to solve something for you. Therefore, carefully read about the reinforcement with foil. Here, too, everything is not easy.

Foil reinforced pipes

Polypropylene pipes reinforced with aluminum are designated as follows: PEX / Al / PEX. There are two types of foil location: closer to the outer edge and in the middle. There is one nuance in the installation of reinforced polypropylene pipes: the foil should not be allowed to come into contact with the coolant. Because even if water is used as a heat carrier, it is not chemically neutral (salts are always present even in soft water). Entering into an oxidation reaction with the foil, water destroys it, seeping further and further into the pipe. Sooner or later (rather sooner) such a pipe will break. For a descendant, almost all European manufacturers produce pipes with foil located closer to the edge. It is they who require stripping: removing the outer layer of polypropylene and foil. But as a result, during welding, it turns out that the metallized layer is protected from interaction with water by a thick layer of material.

When using pipes in which the foil layer is in the middle, not stripping is required, but trimming. For this, a special device is also used, but of a different plan - it cuts off the foil inside the pipe by a few millimeters without destroying the layers of polypropylene. This procedure is simpler and faster (sellers call such pipes "lazy" understand why?). In principle, if the seam is made correctly and correctly, polypropylene is welded to each other, then such a seam is more or less reliable. But if there is a micropore, then water will penetrate into it and cause the pipe to delaminate. And the presence of micropores is guaranteed with an insufficiently vertical cut, insufficient experience (incorrect exposure during welding) and incomplete removal of the foil, and it is unrealistic to control how carefully the foil is removed between the polymer layers ... All this is fraught with ruptures, leaks and violation of the integrity of the system. How they are formed is shown in the figure below.

Such a phenomenon brings especially a lot of trouble when your pipes are hidden in the wall or in the floor. Repair will be long and difficult. In some cases (in winter) it is faster to make a new wiring “on top”, leaving the old one in the wall (but draining the water). And micropores in the seams happen very often: it is almost impossible to control the quality of the foil removal between the layers of polypropylene, which means that it is unrealistic to guarantee the tightness of the seam. And this is in the case of a high-quality pipe, but what if a fake comes across, like the one in the photo above? How to trim such a product? The quality of the seam is generally out of the question.

Weld difference after several years of operation (click to enlarge)

This arrangement has one more drawback: only the upper part of the pipe material is welded to the fitting, and not both layers. And this, even under the condition of welding without a microgap, significantly reduces the reliability of the pipeline. On the other hand, such products (sloths) are much cheaper than their European counterparts. Everything is explained simply here: they are produced by firms that are trying to win in price (Turkish and Asian manufacturers). But how will these savings affect the future? Most likely, an urgent replacement or repair of a part of the pipeline, or the entire system, will be required.

All of the above is true for a continuous sheet of foil as a reinforcing layer. But there is also perforated foil. It is produced by the Turkish company Kalde. The manufacturer claims that due to the presence of perforation, it is not necessary to remove the foil layer: when welding through the pores, adhesion of materials occurs, which ensures the strength of the joint. As far as durability, it's probably the same. But what about the reaction of foil with water and oxygen permeability? Surely these figures are worse than those of pipes with solid foil. Although here the situation is the same as in PPR pipes reinforced with fiberglass: when using high-quality aluminum radiators, the system will serve for a long time.

Results

I don’t know about you, but for myself I can draw the following conclusions. If the wiring is hidden, polypropylene pipes reinforced with solid foil are definitely needed. Moreover, the foil should be located closer to the outer edge, and not in the middle. If the pipes are located “on top”, it is quite possible to use high-quality pipes for heating with fiberglass (but not in those systems where there is a solid fuel boiler).

Reinforced polypropylene pipes. The material is completely new, for only a few years it has been used in the installation of water pipes and heating systems.

Let's see what types of reinforced polypropylene are produced, by what signs they can be distinguished and, most importantly, what to choose when buying.

Problems of polypropylene

There is no bad without good. A great example of positive thinking. Unfortunately, the opposite is also true: there is no good without bad. There have already been so many praises for polypropylene pipes that they simply cannot but have shortcomings.

Indeed, there are circumstances in which polypropylene is better to be preferred to other materials.

The reasons lie in the properties of the material itself:

Polypropylene - fusible plastic;
It has a large coefficient of thermal expansion.

Let's focus on his problems.

Temperature

The melting point of polypropylene is 175 C. However, it begins to soften at much lower 140 C. As for the guaranteed temperature at which the polypropylene pipe must work guaranteed, it is only 95 degrees Celsius (and even less for some varieties) .

What is the reason for such a significant reinsurance with temperature has already been written more than once. Now we only note that at high pressure and high temperature acting on the material simultaneously, it is much less resistant than under the influence of each of the factors separately.

Heat elongation

All materials expand when heated. Some are less, others are more. Polypropylene expands quite strongly.

This is inconvenient for the following reasons:

Aesthetics. A long straight pipe, having lengthened, goes in untidy waves.

Integrity of decorative coatings. If the pipes are recessed under the screed on the floor or in the wall covering, then when they are lengthened, after some time they will inevitably cause the coating to crack.

Decision

Reinforced polypropylene pipe - "our answer to Chamberlain." Of course, its material does not magically begin to compete with tungsten in refractoriness and does not become harder than diamond. However, the polypropylene reinforced pipe is completely devoid of one of the shortcomings of the material, and the other is partially.

How?

But how.

Reinforcement simply forms something like a rigid frame and does not allow the pipe to lengthen, and at the same time grow in thickness.
Polypropylene is soft at heart. No - so no. They don’t let it go in length - we bend the polymer molecules so that each individually coils like a snake, and all together remain in place.
What happens when the pipe is heated to the softening point of the material with a lot of overpressure inside?
She starts to inflate like a balloon. At the same time, the walls are getting thinner and thinner, and if so, it’s easier to push them through the water inside.
Finally, a loud "Bang!" - and the fountain of boiling water causes an attack of sociability among the neighbors below, and at the same time renders all the electronics and books at home unusable.

So, reinforced polypropylene pipes, thanks to the notorious “frame”, do not even begin to deform. In fact, this one does not swell during continuous heating, but simply flows down, reaching a temperature of 175 C.
However, this does not prevent manufacturers from declaring for them the operating temperature of the same 95 C. God saves Berezhenogo.

Types of reinforcement

Undoubtedly, in the coming years, manufacturers will please with something else; in the meantime, a reinforced polypropylene pipe can use two main materials to increase its strength: aluminum and fiberglass (fiberglass).

Aluminum

Polypropylene pipe reinforced with aluminum, in addition to the diameter, may be different in the location of the reinforcing layer. It can be an outer shell for polypropylene, or it can be hidden between layers of polypropylene. In the second case, the presence of reinforcement can only be determined by looking at the pipe section.

Layers of aluminum foil (this is exactly foil; unlike metal-plastic pipes, the metal here is from 0.1 to 0.5 mm thick) is connected with polypropylene glue. The quality of the adhesive joint, along with the composition of the polypropylene itself and the thickness of the foil, determines the quality of the pipe. Alas, it happens that under certain conditions, cheap and low-quality pipes delaminate. Strength at the same time, you know, suffers.

Fiberglass

Fiberglass is an alternative to aluminum. Fiberglass reinforced polypropylene pipe is a completely different design than the previous version. If you, by analogy, imagine a pipe covered with glue with a mesh, you are mistaken.

Inside and outside such a pipe is actually polypropylene, and in the center - fiberglass; however, at the same time, all layers of the pipe - there are usually three of them - are a monolith.

The fact is that when fiberglass-reinforced polypropylene pipes are made, the middle layer is welded to the inner and outer ones - after all, it is based on the same material, only pre-mixed with fiber fibers - the same fiberglass. Two in one: polypropylene glues the fibers, and they do not allow it to deform.

Mounting Features

The principle of assembling a water supply or heating system from reinforced pipes is the same as in the general case: pipes are cut to size, chamfered, pipes and heated with a special simple soldering iron, after which they are combined at one point in space-time. A few seconds - and instead of two parts, one, absolutely monolithic.

However, there is a difference: polypropylene pipes reinforced with aluminum require one more technological operation. This is a purge. Before sticking the pipe into the nozzle, a layer of aluminum must be removed from it. Nothing complicated: the pipe is inserted into a simple clutch with knives, one or two turns - and you're done.

For pipes with an aluminum layer inside, a slightly trickier tool is used - a trimmer. He selects the inner layer from the very end of the pipe so that the end is securely welded to the fitting.

This ensures that the pipe:

Will not begin to exfoliate;
That aluminum will not be destroyed due to electrochemical processes that begin in the presence of metals and at least some potential difference.

And what about polypropylene reinforced with fiberglass pipes?

But nothing. From the point of view of welding with a fitting, their internal reinforcing layer is no different from polypropylene. And if so, no additional operations are needed.

Real strength

What pressure can a reinforced pipe withstand?

This is determined by its belonging to a certain class. It is worth considering the temperature of the water. So, the pn25 polypropylene pipe reinforced with cold water, as is clear from its marking, normally operates at a pressure of 25 kgf / cm2 (the real destruction of the pipe, by the way, occurs at twice the pressure). At the same time, for water heated to 90 C, the calculated pressure drops to 9 kgf/cm2.

Appearance

You can reliably find out if the pipe has reinforcement and, if so, what type, when looking at its cut. Aluminum-reinforced polypropylene pipes have a thin layer with a metallic sheen (of course, we are talking about internal reinforcement. The external one leaves no doubt).

Polypropylene pipes reinforced with fiberglass are distinguished by the presence of three layers of approximately the same thickness, of which the middle one has a bright color marking. The color does not say anything about the characteristics of the pipe. The manufacturer chooses it solely based on his sense of beauty 🙂

disadvantages

With aluminum reinforcement, everything is clear: it needs to be cleaned, and it can peel off. And what about a polypropylene pipe reinforced with fiberglass? Is she literally manna from heaven?

In general, yes. The disadvantages of fiberglass reinforced polypropylene pipes seem mostly far-fetched. These include the fact that the pipe allows atmospheric oxygen to saturate the coolant, which causes, they say, accelerated corrosion of the boiler metal. However, none of the critics gives convincing figures.

findings

Looks like we have a clear favorite. A cheap, durable pipe that does not have any significant problems. We hope that choosing it as a material for home plumbing will not disappoint you.