Properties of plastic piping
All plastic pipes can be divided by the material of their manufacture: they are made of polymers, polyethylene, polyvinyl chloride. These materials have good hygienic characteristics, so they are perfectly suited for the arrangement of heating networks, as well as for the organization of the water supply in the apartment.
It is not always possible to bend the material yourself, so you have to use popular methods
To bend a plastic pipe yourself, you need to learn more about its properties:
- Ring stiffness. High rigidity of PVC can withstand atmospheric pressure of 120 atmospheres.
- Resistance to heat. Plastic is resistant to heat, so it is used for the arrangement of water piping with hot and cold water, as well as to organize the pipeline with heating. Plastic elongates only 5% when heated.
- Low frost resistance. Because of the low resistance to frost, the materials can not withstand temperatures below.15 degrees, so require additional thermal insulation.
- High permeability to light. Dyed in different colors PVC pipe is resistant to ultraviolet.
PVC products for arrangement of the pipeline are available in various diameters
When heated, plastic pipe can be carefully bent, because it has good elasticity. Products made of bendable polyvinyl chloride in the production can initially be coiled into rings. in such a form they come on sale.
How to bend a pipe?
Incorrect bending technology leads to frequent failures of the heating system. Expert advice on bending:
Drawing of the bending process using river sand
- The metal pipe should be filled to the brim with dry sand and installed on both sides of the plugs. If you find a soft material, it can easily be bent with your own hands. Pipes that have a large diameter are best bent with clamps. Aluminum or steel structures are first filled with sand, then the place of the bend is heated with a gas heater. It should be heated to a bright red color;
- Metal plastic pipes can be easily bent by your own hands without using additional tools or electric devices. However, it is necessary to consider their susceptibility to rupture, so every 2 cm cannot be bent more than 15 degrees. The second way: Insert the steel wire inside and start bending. This way you will achieve a better and more even bending;
Parameters of polypropylene pipes
If you do not succeed, then we recommend that you choose a pipe bender. The special tool is a crossbow, spring, segment, hydraulic, electromechanical and manual type.
How to bend a cross-linked polyethylene pipe
Despite the fact that for heating and water supply systems in the construction market are presented pipes made of metal, metal-plastic and polypropylene, in recent years another new type of material has appeared. cross-linked polyethylene. The article will talk about what this material is and what its advantages are. And also will be given instructions on how to install cross-linked polyethylene with their own hands.
What are cross-linked polyethylene pipes?
The main raw material is polyethylene dense polyethylene. Making pipes out of it is a complicated technological process. The addition of chemical compounds and the effect of high temperature, pressure and electron irradiation produce a three-dimensional structure in the solid material. It is then cross-linked in the extruder.
All this allows to create a unique material that has properties inaccessible to metal and plastic.
- Perhaps the most important advantage is the molecular mechanical memory. When they are deformed through fracture, expand when water freezes in them or overlap. Cross-linked polyethylene pipe completely restores its look and all its technical features. For this purpose it is enough to heat it with a construction hairdryer. at this point the material acquires the shapes that have been given to it by the extruder. This important property allows you to use them for water supply in the street and not be afraid that in winter they can burst because of poorly drained water.
Tip: Cross-linked polyethylene itself is resistant to expansion from the inside, but the plumbing inevitably consists of metal parts as well. Therefore, it is not advisable to deliberately leave water in the heating system, at the risk of sub-zero temperatures. But they will become a safety net in case of force majeure, for example, when the heating boiler shuts down.
- The absence of ferrous and calcifying deposits in cross-linked pipes is a second advantage. This is important for both heating and plumbing systems. Internal reduction in the diameter of the pipes will lead to reduced efficiency of heating, and in the case of the water supply. to permanent clogs, bacteria breeding and unpleasant odor. All of this can be avoided by using cross-linked polyethylene pipes.
- When working with pipes no additional seals are needed for connections with fittings. Over time, they wear out and leakage occurs. Soldering density of all fittings is so high that pipes made of cross-linked polyethylene are used for water heated floors, which are installed in a concrete screed and to replace individual elements will be if not impossible, then very difficult and expensive.
- Low weight. Due to their light weight and plasticity they can be easily transported even in a passenger car.
- Long and safe in operation. It is an ecological material, harmless for humans and the environment. It does not corrode and does not react to chemical influences. Guaranteed service life of over 50 years.
Important: Cross-linked polyethylene pipes have a low resistance to direct exposure to UV radiation. Therefore, it is recommended to use them for concealed wiring or in rooms without windows.
Tip: If they are used for repairs, you must first make sure that the pressure and temperature in the heating system of the house corresponds to the recommended values that are specified for specific pipes.
Types of cross-linked polyethylene pipes
There are 2 types of cross-linked polyethylene pipes:
- Universal, which are equally suitable for heating systems in an apartment or a country house, as well as for underfloor heating, which is mounted in the screed and works with hot water;
Important: pipes designed for heating withstand temperatures up to 95 ° C and pressures up to 10 atmospheres. But in an emergency situation, when the pressure can jump to 20 atmospheres, and the temperature 100-100 ° C, also cope without loss of its technical characteristics.
- For heating in pipes made of cross-linked polyethylene is allowed to use water or antifreeze.
- Most pipes can be used for a country house, but when connected to the central heating system in an apartment, cross-linked polyethylene pipes must have a special marking. It means that they have an additional thermal insulation jacket.
- Pipes for water supply, no matter universal or specialized, are safe and environmentally friendly. They are allowed to be mounted on drinking water.
- Cross-linked polyethylene pipes have standard diameters, but special solder fittings, threaded connections and gutters for fixing along the wall are used for fixing. They guarantee solid connection and beautiful appearance in case of external wiring.
According to the processing of raw materials they are divided into 4 categories with corresponding markings:
- PEXa. cross-linked pipes are treated with peroxide;
- PEXb. processed with gas;
- PEXc. pipes are irradiated with electrons inside an electromagnetic field;
- PEXd. the pipes are treated with nitrogen compounds.
Main manufacturers of cross-linked polyethylene pipes
- The most famous brand of cross-linked polyethylene pipes is REHAU (Germany). It has been manufacturing specialized and universal pipes under the brand name RAUTITAN for many years. The range has all sizes (from 12 to 250 mm) and 4 types: FLEX, HIS, STABIL, PINK.
- Finnish concern UPONOR has also established itself as a producer of high-quality pipes under the WIRSBO brand. Size range from 12 to 150 mm.
Connection methods of cross-linked polyethylene
There are 3 ways in which cross-linked polyethylene pipes can be joined.
- Electric welding fittings. This is a highly efficient method. But the implementation requires special equipment and skills, so it belongs to the less common methods.
- Press fittings. They are available from manufacturers such as UPONOR, REHAU and Bir Pex. The main advantage is the restorative characteristics of polyethylene. So, when pressing the fitting, the polymers in it fill all the space, and the place of attachment turns out to be highly durable.
- Crimp fittings. This is the easiest and most affordable way to connect cross-linked polyethylene pipes, which is available for home use.
Important: the connection method should be chosen based on the pressure that is expected in the pipes during operation. Each of the above methods can withstand loads only within certain limits.
Tools for connecting cross-linked polyethylene pipes with your own hands
- hydraulic press;
- a set of connecting elements (fittings);
- special shears;
- flat spigot.
- The manifold outlets, to which the pipes will be connected, must be in good condition and provide absolute tightness.
- Before you begin, the workplace must be cleared of dust and debris, so that no dirt can not get into the joints.
- Lay out the required number of pipes and fittings.
- It is desirable to have a diagram of the distribution of the pipes.
- In suburban homes, the water comes directly from the well, so it has a low temperature and condensate forms on the pipes with cold water. And hot water in them quickly cools down and have to pass it each time long enough. To avoid this, the pipes made of cross-linked polyethylene in the water supply system is recommended to put on additional insulation, such as corrugated.
- Because of the high plasticity of pipes, before starting work, they are attached to the wall on special brackets-holders.
How to work with cross-linked polyethylene correctly
- The most important requirement for successful installation of cross-linked polyethylene pipe is a quality cut at an angle of 90°. It should be perfectly perpendicular to the longitudinal axis.
- In order to provide the strongest possible connection in the fittings, the edge of the pipe cut must be absolutely straight, without burrs, notches and waves. If there are the above irregularities, during jointing the edge of the pipe can suffer even more and break the seal. The obviousness of the problem will be clear only during operation.
- For cutting it is recommended to use special pipe cutters. They are shears, which, like a pruner, smoothly cut even a thick pipe without much effort. They come in different price categories and inexpensive models will do for home use.
Installation of cross-linked polyethylene pipes using the compression method
Crimping cross-linked polyethylene pipes is equally suitable for cold water and heating systems. If necessary, it can be easily dismantled.
- The pipe is cut to the required length and the nut is put on the end of it with the thread to the connector.
- Then the split ring is put on. Since it is not tight and has a cut, then to do it with his hands is not difficult. The ring must be 1 mm from the edge of the pipe.
- Then the connection fitting itself is inserted into the pipe, the split ring should be placed directly on the fitting nipple.
- Push up and the nut and using wrenches begin to tighten it. It should fit snugly, but do not over tighten. Otherwise the thread on the fitting can be damaged.
This method is especially good if you are faced with the question of how to join the cross-linked polyethylene without a special press.
Installation of cross-linked polyethylene pipes with your own hands video
Mounting of cross-linked polyethylene pipes with press fittings
This non-pressing method ensures a solid and high strength joint. But it cannot be dismantled if necessary.
- Press sleeve in the form of a ring is put on the pipe.
- Insert the reamer of the desired diameter into the end of the pipe, press the handle and increase the diameter until it is freely slipped on the fitting.
- Fitting is pushed onto the expanded end of the pipe as far as it will go.
- Press sleeve is put on top. After expansion, thanks to the molecular memory of cross-linked polyethylene, after some time the pipe will return to its shape, tightly crimping the fitting.
Installation of pipes made of cross-linked polyethylene by electrofusion
- An electric-welded socket is put on the cut pipe.
- There are special terminals on the fittings for welding. They are hooked up to a welding machine.
- Before cross-linked polyethylene is welded, voltage is applied to the inside of the fitting. It will heat the fittings and the end of the pipe to a temperature of 170°C.
- You only have to switch off the welder and wait until the pipe and fittings have cooled down. Cross-linked polyethylene will return to its original shape. The resulting connection will withstand operating pressures in pipes up to 12 atmospheres.
That’s the end of the installation and the only thing left is to connect the cross-linked polyethylene pipes to the collector.
Hello. Please advise how to bend the cross-linked polyethylene 20, for laying underfloor heating. The store advised to heat a hair dryer, this is correct.
By hand without heating. The heat is not necessary, cross-linked polyethylene is perfectly bendable.
It’s strange, but when you try to bend it 180 degrees with a bend diameter of 200mm, it breaks.
That’s strange. And what kind of pipe do you have??
TECE Systems wrote : Strange indeed. What kind of pipe do you have??
Unidelta PEX-b I think so from memory, next to no. Diameter 20mm.
You’ve never dealt with these pipes? For bending the pipe special brackets fixed on the pipe are used. Look at the recommendations for laying pipes and do it accordingly! The bending radius of this pipe is not less than 350 mm. The smaller bend radius causes the pipe to break! This is due to the wall thickness and diameter of the pipe.
The letter “b” stands for the type of cross-linking of polyethylene. If I’m not mistaken (I could mix up the first two), then
a peroxyl b silane c electron bombardment (radiation) d nitrogen
The silane method is chemical (the others are physical). There are a number of nuances, I will not bore you with this, but I personally (I say this subjectively) do not recommend Pex-b. Pex-c is optimal.
but what type of PEX is better to use for summer cottages, if HTW will be fed to the consumers from the boiler? Use only in summer. A piece of pipe in a corrugation will be underground. Reading, trying to understand, but confused (((. and tomorrow I need to buy a pipe. In online stores PEX-c not met.
Pex-c is, for example, pipes manufactured by the German company Hewing.
In Moscow there is a company called ZAO Egoplast (www.egopast.ru) they order the production of MF-pipes under their brand “Pro Aqua” Hewing (there is also “Pro Aqua” Haka it is worse and the aluminum is thinner, it makes another manufacturer for Egoplast). It uses the c-method of cross-linking (bombardment of polyethylene with electrons from an electron-beam gun)
What is better, it is difficult to say. But Pro Aqua Hewing is a really good pipe.
I do not advertise Egoplastu, if anything. Yes, I used to work there, but it has nothing to do. Just a lot of fakes on Henco the same, alas. Rehau (Pex-a) honestly, have not tried to mount, I will not say.
Installation of metal plastic pipes.
Easy installation. You can connect pipes with press or compression fittings. Fewer joints. Since the pipe bends quite easily it is possible to make curves, which is very suitable for underfloor heating.
The price of fittings and press tool. It’s not recommended to do hidden wiring with compression fittings. Since over time, threaded joints can loosen and leakage will appear.
Metal plastic pipes pros and cons.
Corrosion and chemical resistance due to multilayer complex composition. Elasticity, which allows easy bending of metal plastic pipes; Acid permeability due to the aluminum layer; Used for both hot and cold water supply; Easy and fast installation. It is possible to perform connection of metal-plastic pipes by means of press-fittings, threaded connections or push-fittings; Long service life. The service life of such pipes depends on the pressure and temperature of the water, as well as raw materials, as the manufacturer claims the service life reaches fifty years or more. But it all depends on the manufacturer and the raw material it uses.
Disadvantages: Installation of metal plastic pipe is undesirable to produce at low sub-zero temperatures, narrowed passage section of fittings, the high cost of high-quality fittings for metal plastic pipes, with poor quality installation, possible bends and leaks in the joints. If the material is of poor quality, over time the separation of the pipe. When concealed piping can not be used threaded fittings.
Metal plastic does not withstand UV rays.
Manufacturer does not recommend installing metal plastic pipe on central heating. Since metal plastic pipes have a working temperature of 95 ° C. Maximum short-term temperature that can withstand this type of pipe is 110 ° C, respectively, the service life will be much less.
Installation of cross-linked polyethylene pros and cons.
Easy installation. Almost perfect connections. No diameter reduction at joints like plastic pipes. It is impossible to break the pipe, for example, as a metal-plastic. Fewer joints. As the pipe is quite easy to bend can go through the turns, which is very good for underfloor heating.
Very high price for the pipe, fittings and tools. (If you take the quality material)
Cross-linked polyethylene pipes pros and cons.
Flexible pipe, you can bend within the norm, but at 90 degrees go to the bend. If you bend it more, you can overcompensate. But it is impossible to break. Connections are very strong and 100% of the time do not flow. Withstands sub-zero temperatures, that is, if the water in them freezes you can easily defrost (the pipe expands). And the pipes won’t get damaged or leak. If you bend the pipe to scrap and then heat it with an industrial hair dryer, it will take its original shape, that is, the memory effect. Many different diameters, from 10 mm to 100 mm. It is possible to install at subzero temperatures.
You need to be careful in choosing is cross-linked polyethylene for (low-temperature heating). Cost, if you take a meter of polyethylene pipe and compare it to metal-plastic and polypropylene, it is at least twice as expensive! (Depends on what manufacturer) Expensive fittings and connections. expensive than metal-plastic pipes. Need special equipment for crimping and installation, again, is not cheap. The manufacturer does not recommend the installation of pipes made of cross-linked polyethylene on the central heating. Since these pipes have a working temperature of 95 ° C. Short-term maximum temperature that withstands this type of pipe 110 ° C, respectively, service life will be much less.
How to bend a plastic pipe without a special tool
This category is characterized by high resistance to thermal effects, which allows you to intensively heat the room. Polyethylene structures are made under high pressure. This manufacturing technology not only increases the strength, but also allows you to produce structures with different density. The most stable and workable density of cross-linked is 55-80%. Note, the higher the density, the more will cost polyethylene pipe.
The structure of a cross-linked polyethylene pipe
- Silane gas. The technology makes it possible to create structures with a density of up to 65%;
- Peroxide (density 75%);
- Magnetic irradiation (maximum piercing density of 60%).
Scheme of fittings for polyethylene pipes
Polyethylene structures are sealed by special fittings. A ring is put on the end of the hose, then its diameter is widened and fitting is inserted inside. The connection is then clamped with a mounting ring.
Simple Techniques For Round Pipe Bending / Easy Way For Steel Pipe Bending
Calculation of the bend radius
Calculations are used when it is necessary to exactly determine the place of the beginning and the end of the bend. The calculation is simple and comes down to a few steps, which will be shown using the minimum bend radius of 16 mm of the pipe:
- Bending radius. R=5D. In this case, R=516=80 mm;
- For a given radius, the length of the full circle is 23.14R= 23.1480=502 mm;
- The length of the bend depends on the angle at which the pipe will be bent:
- For a 90 degree bend, it is a quarter circle, ie 125.5 mm;
- for a U-bend. half of the circle. 251 mm.
Rules of screed arrangement
If the pressure test was successful, there is no depressurization of the pipes, and the system is completely filled with coolant, then the stage of installation of pipes is complete. Now you can proceed to the screed and the finishing.
For screeding it is necessary to use a purchased or self-made mortar based on cement grade M300. The minimum height of the screed, providing protection for polyethylene pipes, is 3 cm above the laid pipe. This thickness is optimal for a uniform heat distribution.
In most cases the screed is done as a continuous screed without expansion joints. Thermal joints are necessary when:
To create seams the damping tape is used. The thermal joints are treated with sealant.
Is it necessary to do reinforcement before pouring screed? There is no definite answer to this question. Experience shows that the system works perfectly without reinforcement, but at the same time a reinforcing layer gives additional strength to the screed. For reinforcement you can use made of metal or plastic mesh 100×100 mm.
Reinforcement will also be useful only if the reinforcing mesh will not just lie on top of the pipe system, and “sink” in the mortar, when hardening being in the screed.
Correct installation of reinforcement complicates the laying of the screed, so when there is no experience or confidence that everything can be done correctly, this step can be skipped. After the pouring of the screed the system can be started not earlier than 25-30 days.
As the final finish. the top layer of the “pie” can be used any floor covering
Fittings for laying pipes
The Rehau company offers sliding sockets and fittings, providing high reliability of connection of cross-linked polyethylene pipes. In the course of installation, the pipe is first fitted with a sliding sleeve. Then a special expander can be used to expand the inner diameter of the product to the desired value. This operation will require several techniques. Next, the socket is secured to a fitting with a suitable diameter, and then the sleeve is pushed over it. Such connections have a very high degree of resistance to most corrosive influences (including increased pressure and heat).
If you have all the necessary tools, the installation of a water heated floor of cross-linked polyethylene does not take too much time. Usually no special skills are required: the main thing is to strictly follow the instructions. Thanks to the absence of rubber components in the system it is possible to achieve a significantly longer service life. We are talking primarily about seals made of rubber, which rather quickly fail.
Conclusion and useful video
The rules of calculation of the floor heating system are given in
After laying the pipe it is important to test it before performing further installation work. About this in Homemade craftsmen often make mistakes when assembling underfloor heating
The main problems of installing polyethylene pipes are covered in the video clip:
Homemakers often make mistakes when assembling underfloor heating. The main problems of installation of polyethylene pipes are highlighted in the video clip:
Properly selected and installed a warm floor without much cost will make the home warm and comfortable. Technology for the device of the floor heating circuit of PE-pipes is simple and can be used not only by professional builders, but also by ordinary people. If you follow all the rules and recommendations the system will serve you properly for a long time.
Have you ever laid polyethylene pipes when constructing a warm floor? Perhaps you know the technological nuances that are not mentioned in the article? Please write 0. Ask questions, post photos in the block below.
Basic bending methods for PVC
Using a pipe bender is only necessary when you can’t bend a plastic pipe yourself. This applies to large-diameter products, which are intended for the arrangement of sewage.
Here’s what can happen if you do not act according to the rules: this material can not be used for the pipeline
Modern masters successfully use the method of heating with a hair dryer, use sand, wire and mandrel to create the necessary turns in the design of the pipeline.
Using a hair dryer
The melting temperature of PVC products starts at 140 degrees Celsius, but these temperatures can completely melt the element, depriving it of its integrity and basic technical characteristics. To avoid this happens, it is recommended to use a construction hair dryer for gradual heating of the PVC product. Polypropylene pipes are also subject to melting at high temperatures, therefore, they can be bent by a similar method:
- Creating a template for bending. Before carrying out the responsible procedure, it is advisable to create a template for bending: it is better to make it out of a sturdy material. You can buy ready-made corners, using them to make turns.
- Filling with loose material. To prevent the section from melting and took the right shape, masters advise to pre-fill it with salt or river sand. You can do this with a funnel: 3 meters of pipe with a diameter of 20 mm will require less than one bucket of sand.
- Heating the section with a hairdryer. To heat the material use a technical hair dryer. First select the area to be heated, then the temperature is set on the device and the heating is done.
- Bending the product. As soon as the element is heated to a state in which it can safely bend. it should be transferred to the template and carefully bend to shape.
It is important to avoid excessive melting and heating to a temperature of 170 degrees. In this case, the plastic will become melted and unsuitable for further use. After the pipe has cooled on the template, it is mounted in the pipeline.
Using sand to bend the pipe
No need to use a construction hair dryer when using sand. The essence of the technique is to heat salt or river sand on a tray. Heating to the desired temperature takes place, using a ladle, the composition is poured into the pipe. The whole procedure is as follows:
- heated sand using a ladle is poured into a plastic tube through a funnel;
- a metal stopper is placed on the back side to keep the heat from escaping
- the minimum temperature for heating sand or salt in the tray should be no less than 140 degrees and no more than 170 degrees.
When the loose substance, heated to the desired temperature, placed inside, it begins to affect the rigidity of the plastic. Melts gradually, so it is easy to bend. Here, it is also desirable to use a special template for bending, so that the turn turns out even. If the result does not meet the requirements, such an item cannot be used for safety reasons.
Bending plastic pipes with wire
You can bend pipes with a metal wire. In this case, two variants of work are used:
To bend a PVC pipe for heating or plumbing at home with a wire, you need to arm yourself with pieces of metal material along the length of the piece of pipe. Prepared pieces are inserted inside, completely filling its inner diameter. If you do not cover the entire hole with a wire, it will create unnecessary pressure, provoking incorrect bending. This way you can bend the material only if there is a support.
It is necessary to use a thick and strong wire. then the plastic is easier to bend
The use of a metal spring implies its placement inside the tube, so the diameter of the spring must match the diameter of the element. Before bending the product with a spring, it is necessary to tie it with a wire, so that further removal was easy.
The nuances of bending a pipe with a mandrel
This procedure is performed in several steps. To bend pipelines with the mandrel, it is necessary to follow all rules; it is better to buy or rent a forming machine for the work. The steps of the procedure are as follows:
- Making a frame. You can make the frame yourself out of fiberboard. Such a device is necessary to create the correct shape of a bend.
- Silicone casing. This attachment is necessary to prevent scratches, defects and dents. To create a bend of a plastic pipe it is better to use a forming machine.
- The bending procedure. The product is inserted in a silicone casing, fixed in a fiberboard frame. The structure is placed in the molding machine, the place of the supposed bending is heated, the plastic begins to bend to the shape of the frame.
It takes 10 minutes to remove the pipe. After it has cooled down, it can be used to construct a pipeline.