How to connect a HDPE pipe with polypropylene. How to connect a pnd pipe with a polypropylene, metal pipe Pipe pnd 32 connection

Low-density polyethylene pipes are a very common type of pipeline for cold water. How to properly connect a HDPE pipe and in what cases what method to use will be analyzed in detail. Inexpensive and practical products can be easily assembled with your own hands, but this issue also has its own characteristics.

Low-density polyethylene is a plastic that has been known for a long time, but pipes from it began to be produced more than 50 years ago. The abbreviation HDPE (low pressure polyethylene) is a designation of the material production method and does not matter to the quality of the material.

Produced in different colors. This is necessary so that the buyer knows their purpose:

for a domestic pipeline with drinking water - blue products or black with a blue stripe;
for technical structures - just black.

The diameter of the pipes can be different, its value varies between 16-1600 mm. On sale is:

measured cuts - 6 or 12 meters;
in coils (with a diameter of 160 mm).

Advantages and disadvantages of low pressure polyethylene pipes

These products have many positive qualities, the most significant are:

low cost when compared with metal-plastic or steel;
smoothness of the surface of the inner walls, this prevents clogging and the formation of salt layers (as in metal);
complete chemical inertness - does not react with acidic substances and alkalis;
long service life - an average of 50 years;
they tolerate freezing well - they do not burst, like, for example, metal ones;
plasticity - the material perfectly tolerates soil movements;
high resistance to temperature extremes;
manufacturability is the ease and speed of installation;
environmental friendliness - does not evaporate harmful substances;
light weight, which facilitates installation, transportation and storage.

There are a number of disadvantages to be aware of:

Sensitivity to ultraviolet radiation. Do not leave water pipes in areas with open sun in the "naked" form. It will collapse during the first few years of operation. For this reason, this material is used in the creation of underground water pipes or indoors.
Polyethylene cannot be used to transport hot substances.

Connection methods

How to connect plumbing pipes

- these are styrenes that are popular, and deservedly so. Their list includes:

HDPE products;
propylene;
polyethylene;
crosslinked polymers.

They connect in different ways:

with fittings;
welding using a soldering iron for HDPE;
compression.

Connection of PVC and HDPE pipes

To connect two different materials - a polypropylene pipe with HDPE, the following are used:

threaded fittings;
flanges;
combined couplings;
collet coupling.

Features of each connection:

The transition from PVC to HDPE using threaded fittings involves disassembling the element and fixing it by welding.
The transition from HDPE to polypropylene using a collet coupling also consists in disassembling the structure, fixing each end with a specific element.
A flange connection with a polypropylene pipe is used in the construction of risers, sewers and other communication structures with a large diameter.

How to connect HDPE pipe with metal-plastic

Plastic pipe products belong to the budget category of building materials. Often there is a need to connect with more expensive metal-plastic. The only acceptable type of transition from HDPE to metal-plastic is to use special threaded fittings.

The video shows this connection option in detail.

The connection of HDPE pipes can be done independently. The home master only needs to deal with some of the nuances and general rules for performing such an event.

Now HDPE products are very actively used for the construction of pipelines for various purposes. Most often, gravity and pressure water systems are mounted from these. They are connected in two ways - by one-piece and detachable technologies. The second technique is more common. But the one-piece technology for creating pipelines of any length is used quite often.

Pipe Welding Process

It is produced by the following methods:

Butt welding. In this case, the ends of the fittings used for HDPE products and the pipes themselves are heated and melted. After that, their ends are pressed (a special device is used for these purposes, it is called a hand iron), which leads to a monolithic seam. The latter, in terms of its technical and operational characteristics, is completely identical to the material of HDPE pipes. When welding butt, fittings and tubular products with the same cross section should be used.
Edge welding (also called pressing). This technique is recommended for non-pressure water supply systems, when it is required to connect the inputs of wells or collectors to the ends of HDPE pipes. Press welding is performed with special types of rods (PE electrodes).
Nest welding. It is carried out according to the same technique as butt welding. But with the nested method, it is necessary to use fittings, the inner section of which is similar to the outer diameter of the tubular products being welded.

In everyday life, high-density polyethylene pipes are usually butt-welded. Edge and nesting techniques are used less frequently. In addition, there is another one-piece method for connecting HDPE products. It's called electrofusion. With such welding, fittings and pipes must have the same section. The electrofusion circuit requires the use of couplings. They have a special design. In the couplings for the described welding technique, a heating grid is fused in the factory. It has two electrical contacts. Their ends are brought out.

In addition, electrofusion soldering sleeves have unique barcodes. In cases where the work is performed by an automatic unit, it itself determines the appropriate mode for performing the welding operation by reading the applied code.

If there is no automatic welder, the specialist needs to independently set the appropriate operating mode for the device, focusing on the features of the coupling used. All permanent connections have a serious drawback. If any part of the pipeline fails, it will not be possible to quickly replace the couplings or fittings. Work on their dismantling (and then on the installation of new products) will require significant labor and time costs. Therefore, it is better to connect HDPE products using detachable methods. We will talk about them further.

For the assembly of water pipes, couplings made by extrusion from polyethylene are often used. With the help of such fittings, the installation of pipelines is carried out really quickly. And there is no need to use special equipment. Couplings are compression, reduction and connecting. The latter are the simplest. They are designed to connect elements of plumbing systems of equal cross section. If it is required to create a network of different diameters, reducing couplings should be used.

Couplings for connecting pipes

Compression fittings are used to assemble water and gas supply systems from HDPE pipes. Such couplings may have internal or external threads. Mounting them is very simple according to the following diagram:

Clean the end of the pipe from debris and dust, chamfer the end of the product with a construction knife (it must be well sharpened) or a special beveler.
Unscrew the union nut and disassemble the compression connecting element.
Make a mark on the tubular product with a marker, which marks the depth of the pipe's entry into the connection.
Lubricate the end of the HDPE product with liquid soap or a silicone-based compound to ensure that the pipe is inserted into the coupling as easily as possible.

Now you need to insert the pipe to a predetermined depth with some (rather serious) pressure and put the nut in place (just screw it all the way). Note that experts do not recommend using any tool to tighten the nut. This work is best done by hand. Then you definitely will not damage the pipe and will not break the thread.

In addition to the ease of self-assembly, polyethylene couplings are characterized by several other advantages:

increased resistance to temperature fluctuations and mechanical stress;
excellent level of connection reliability;
wide scope of application (couplings are suitable for any piping systems);
long service life of the gas or water supply network.

We also note that polyethylene fittings have a low cost. This, you see, is important. It is worth adding that when assembling gravity systems (for example, sewer), HDPE pipes can be connected using the simplest method - into a socket. No fittings are needed in this case. It is only required to insert the end of another product into the socket of one pipe. And then seal the connection made with a silicone compound or elastic special cuffs.

When repairing domestic water supply networks, there is often a need to connect a metal pipe and a low-pressure polyethylene product. It is not difficult to carry out such an operation with your own hands. The operation is performed in two ways: flange connection, threaded fittings.

Flanged pipe connection technology

Flange technology is optimal for joining large-section (100-110 mm) pipes. It involves the use of simple slip-on flanges, which are placed on the ends of tubular products. Also, sometimes flanges are welded to the pipe and connected to bushings. This technique is recommended for pipelines that often fail and require regular dismantling.

Threaded connections are more suitable for mounting small pipes. To perform the docking operation of such products, you need to buy fittings with a special design. They consist of: a smooth sleeve (an HDPE pipe is inserted into it) at one end of the fitting; special threaded connection on the other end for a steel pipe. Any home craftsman can connect tubular products from different materials using a threaded fitting. Moreover, he will complete all the work in the shortest possible time.

Thus, using a variety of fittings, you can assemble pipelines of any configuration from products made from different materials.

Currently, plastic pipes are actively replacing competitors from other materials in the field of gas supply, water supply and sewerage. One of the most popular products on the market for water supply are HDPE pipes.

What is HDPE pipe?

HDPE stands for low pressure polyethylene. It was polyethylene that became one of the first polymers used for the production of pipes. In stores, they are usually presented in the form of black bays, 25 meters or more, of different diameters.

Usage

The polyethylene pipe has found wide application in many areas: plumbing, heating and gas facilities, sewerage and drainage, laying commutations and as an external protective layer.

We are primarily interested in the installation and installation of water supply using HDPE pipes. Black pipe, with blue longitudinal stripes, with the inscription for drinking water and the indicated diameter. A blue stripe indicates that the pipe is for cold water supply. Pipes with a yellow stripe are for gas.

Advantages of HDPE pipes over metal:

Simplicity and ease of installation;
The service life is about 50 years, which is 2-3 times longer than metal pipes;
A light weight;
Low thermal conductivity;
The ability to expand (the pipe will not burst in the cold);
Operating temperatures from -20°С to +40°С;
Low noise;
Wide choice of diameters and lengths.

How to choose a HDPE pipe

Recommended parameters: for an average suburban area, standard bays of 25 meters with a wall thickness of 2 mm are ideal. The diameter should be chosen depending on the pressure of the water in the system: if the public water supply or water source has good pressure from a pipe of more than ¾ inch, then feel free to take a 25 HDPE pipe. If the water source is a ¾” metal pipe, then a 20 mm pipe should be taken. The outlet diameter must be smaller than the diameter of the main pipe to ensure good pressure.

Although the service life of a polyethylene pipe is about 50 years, it will not be out of place to pay attention to the production date, which is indicated on the pipe marking along with the diameter and wall thickness.

The outer diameter of HDPE pipes varies from 10 to 1200 mm, but the most popular are 20 mm, 25 mm, 32 mm.

Diameter matching

For fittings made of metal, and for connection with a metal pipe ¾ inch (inner diameter 20 mm, outer diameter approximately 25 mm), a 25 mm HDPE pipe is suitable. Accordingly, metal threaded connections will coincide with the components of the HDPE pipe.

Metal pipes and fittings with a diameter of ½ inch (inner diameter 15 mm, outer diameter approximately 20 mm) correspond to a 20 mm HDPE pipe.

Do not forget that it is always possible to use adapters to reduce and increase the diameter of the components of the plumbing system, but with damage to the pressure in the system.

Do-it-yourself installation of HDPE pipes

If you loved to play constructor as a child, then installing a water supply system using polyethylene pipes is not difficult. Connecting pipes takes a few minutes and does not require the use of tools.

Possible options for connecting hoses and taps to the HDPE pipe

In advance, draw a plumbing diagram and the number of required taps. Installation and laying underground is possible. It should be noted that a new, just unrolled pipe, is trying to twist, taking on its previous shape. Therefore, one of the options for facilitating installation is to fasten the pipe with electric clamps to an old water supply or along a fence. Clamps are recommended to take a width of at least 4 mm. Another option is to unfold and straighten the pipe before installation, pressing it down with something heavy in several places along the entire length and leave it for a couple of days.

Types of fittings for HDPE pipes

To connect the HDPE pipe to the plumbing system, thermal welds or threaded connections are used. The pipes are connected to each other with special clamping joints, which allows you to quickly replace the damaged section of the pipe or increase the length.

For a joint with a metal pipe or fittings with threaded connections (faucets or spurs), compression elements are used, on the reverse side of which an internal or external thread is made.

Compression tee - a joint of 2 pipes and a thread for connecting a tap or a clamp connection for draining a HDPE pipe. There are options for connecting a pipe outlet of a smaller diameter.

Compression butt joint - serves to lengthen, increase the length or transition to a smaller diameter of the pipe.

Swivel 90°

Compression valve

With the correct connection, due to the design, smudges are excluded. At the joints of metal - HDPE, we recommend using a fum tape.

Let's try to figure out how the connection "works". The photo above shows a regular joint, thanks to which you can lengthen the pipe. Left unscrewed blue nut and clamping ring. It is thanks to the clamping ring that the pipe is tightly fixed in the connection. The ring is made of hard plastic with sharp notches, which, when tightening the nut, cut a little into the HDPE pipe.

A white, translucent, sealing sleeve is visible from the connector housing to the right, which in turn presses a rubber ring that prevents water from flowing. Below, in the photo, you can see all the parts of a simple connection system.

The first "nut" serves for the rubber ring and the coupling, while the pipe itself reaches the middle of the butt joint.

Now the most important thing: the connection process. It is advisable to cut the pipe with a hacksaw with a fine tooth, cut off the burrs. Next, unscrew the blue nut, take out all the parts and sequentially put everything on the pipe.

The mistake of many people is that during installation they do not disassemble the connection, but try to unscrew the nut a little and drive the HDPE pipe there by force. After that, leaks occur - the pipe does not enter the connector deep enough.

We put the connector on the pipe as strongly as possible and tighten the nut until it stops, as far as there is enough strength. We enjoy the result of our work!

Modern plumbing is rarely made of metal. He has worthy competitors - polymers, which are gradually replacing him in many areas. One such material is low density polyethylene. Pipes for pressure pipelines are made from this material, that is, for water pipes and even for gas pipelines. This type of material is becoming increasingly popular, as the connection of polyethylene pipes is easy to do with your own hands. You just have to follow very simple rules.

Advantages and features of the application

Polyethylene pipes are made from low pressure polyethylene. This material is abbreviated as HDPE. It is characterized by increased strength and elasticity, has good performance properties:

chemically neutral, can be used for food transportation;
smooth walls prevent the formation of plaque inside;
not subject to corrosion;
low coefficient of thermal expansion - about 3% at maximum heating (up to + 70 ° C);
they normally react to the freezing of water inside, due to elasticity they increase in diameter, and after thawing they take on their original dimensions.

One moment to remember! If you need pipes that are resistant to freezing (for example, for), look at the description or technical specifications when choosing. Not all types of copolymers that are used for the production of pipes tolerate freezing well. So be careful.

The main disadvantage of polyethylene pipes is the restrictions on the temperature of the transported medium: it should not be higher than + 40 ° C, that is, only cold water supply can be made from HDPE, they cannot be used for hot water and, moreover, heating.

Another point: polyethylene does not tolerate UV radiation. With constant exposure to the sun, the material loses its elasticity, and, after a while, breaks (some manufacturers make HDPE pipes resistant to ultraviolet radiation, but they are more expensive). Therefore, open laying of water pipes from plastic pipes is very undesirable. But it is very possible to lay a pipe in a trench from a well or well to the house, to make cold water distribution around the house. This is a fairly economical and convenient solution, since the installation and connection of polyethylene pipes is not a very complicated matter. If we are talking about a detachable connection, then no equipment is needed for it. All you need is fittings and hands.

Which polyethylene pipes are better

For the production of water pipes, two grades of polyethylene are used - PE 80 and PE 100. The hundredth polyethylene is denser and more durable than the eightieth. For water supply systems of a private house, the strength of PE 80 is more than enough - they can withstand pressure up to 8 atm. If you like a large margin of safety, you can take them from PE100. They work fine even at 10 atm.

What you should pay attention to is the country in which this product is produced. Quality leaders are European manufacturers. High precision execution guarantees high reliability of the system. Average quality and prices are from Turkish companies, in a cheaper price segment, Chinese manufacturers. Their quality, as usual, is also much lower. It is difficult to give advice here, everyone selects at their own discretion (or what is in the region).

Types of HDPE pipe connections

There are several types of connection of polyethylene pipes:

detachable (on fittings or couplings);
one-piece - by welding:
- using a special welding machine;
- electric couplings - a heater is built into such couplings, when an electric current is applied to it, polyethylene is heated and fused.

Weld mainly pipes of large diameters, which are used to create main pipelines. Pipes of small diameters - up to 110 mm, used in private construction, are mostly connected using fittings. Couplings are used more often during repair work, as their installation takes more time.

Fittings for polyethylene pipes are shaped parts (tees, crosses, angles, adapters, couplings), with the help of which the required system configuration is created. Since self-connection of polyethylene pipes is carried out more often with the help of fittings, let's talk about them in more detail.

Assembly on compression (crimp) fittings

On one or two sides of the fitting (sometimes on three), a whole system is installed that provides the connection. The fitting itself consists of:

How reliable is the connection

Despite the apparent unreliability, the connection of polyethylene pipes on compression fittings is reliable. Properly made, it can withstand operating pressures up to 10 atm and above (if these are products of a normal manufacturer). Watch the video for proof.

This system is good for easy self-assembly. You probably appreciated it already from the video. Just the pipe is inserted, the thread is tightened.

Summer residents, in addition to the ability to do everything with their own urks, like it because, if necessary, everything can be disassembled, hidden for the winter, and reassembled in the spring. This is in case the wiring is done for irrigation. The collapsible system is also good because you can always tighten the digging fitting or replace it with a new one. The disadvantage is that the fittings are bulky and internal wiring in a house or apartment is rarely made of them - the appearance is not the most pleasant. But for the water supply section - - it is difficult to find better material.

Assembly order

The pipe is cut strictly at 90 °. The cut should be even, without burrs. Dirt, oils or other contaminants are also unacceptable. Before assembly, chamfers are removed from the sections of the connected sections. This is necessary so that the sharp edge of the polyethylene does not damage the sealing rubber ring.

During installation, the connection of polyethylene pipes on compression fittings is tightened by hand

Spare parts are put on the prepared pipe in this order: a compression nut is pulled, then a collet, followed by a thrust ring. We install a rubber gasket in the fitting body. Now we connect the body and the pipe with the parts put on it, applying force - we must insert it all the way. We tighten all the spare parts to the body and connect them with a crimp nut. We twist the resulting connection of polyethylene pipes with force by hand. For reliability, you can hold out with a special mounting key. The use of other tightening tools is undesirable: plastic can be damaged.

Saddles and their scope

In addition to fittings, there is another interesting device that allows you to make branches from an already finished pipeline. These saddles are specially designed couplings. This coupling has one or more threaded holes. They usually put a tap in them, and a new branch of the water supply is connected to it.

Sedeki are put on the pipe, fixed with screws. After that, a hole is drilled in the branch with a drill and a thick drill in the surface of the pipe. When it is ready, a crane is installed, a branch is assembled further. So improve the system with minimal effort and cost.

Flange connections and transition to metal

In the water supply system, elements of the system that do not have a threaded, but a flanged connection can be installed. Usually these are taps or other shut-off or control valves. To connect with such elements, there is a special fitting for HDPE. On the one hand there is a standard compression version, on the other - a flanged version. Installation is standard - with a compression nut on one side, gaskets and bolts on the flange side.

When installing a water supply system from polyethylene pipes, questions may also arise about the connection of polyethylene and metal. For these cases, fittings are used, on one side of which there is a thread. It can be external or internal - it depends on the type of device or transition being installed. Such fittings are available in straight lines, in the form of a 90° angle.

The installation is standard - a thread (with winding neatly) on one side and a crimp nut on the other.

Modern construction is not complete without the use of polyethylene pipes. These products are produced under low pressure and are used in the construction of non-pressure and pressure pipelines. To obtain such pipes, polyethylene is used, which has the grades PE 100 and PE 80. The material has a high elasticity, so it is very easy to work with it, and the laying of the pipeline is carried out in a short time and with less labor. Among the advantages of using such pipes are a long service life, no corrosion, resistance to negative factors, the possibility of trenchless laying of the pipeline, as well as a smooth surface, which ensures the unhindered passage of liquid.

Among other things, polyethylene pipes are lightweight and allow you to quickly mount systems of complex configuration. The material is resistant to temperature changes, has high ductility and mechanical strength. This product can be used in regions with high seismicity as the systems undergo ground movement.

Varieties of polyethylene pipe connections

If you are thinking about how to connect HDPE pipes, then you should first familiarize yourself with the methods of work. Depending on the purpose of the piping system, one of two methods can be used: detachable or one-piece. The first technology provides for the possibility of dismantling during operation. Whereas they do not provide for the possibility of subsequent disassembly. If you decide to use a detachable connection method, then you should use flanges that are made of steel. In this case, the connection is called flange.

Before connecting HDPE pipes using the one-piece method, you should acquire a welding machine, while the pipes will be welded end-to-end to each other, and the master will have to use superimposed couplings. Electrical heating elements are connected to the connection. Among other things, you can use which requires the use of compression fittings. This technology is used on pipelines of small diameter.

Why choose a detachable connection

If you are thinking about how to connect HDPE pipes, you should think about the methods of work. Recently, experts have increasingly advised using the split method, which has a number of advantages over the one-piece method. Firstly, a detachable connection allows you to save money, secondly, it is more affordable, and thirdly, the master will be able to increase the speed of the work. If we consider the first option, then you will not need to use special expensive equipment for welding polyethylene products or pay for the services of a specialist. Moreover, a detachable connection can be made even where the use of welding is not possible, such as underwater conditions. And finally, this method allows you to connect products at high speed.

Detachable connection features

Before connecting HDPE pipes with a detachable method, you should choose a method that can be socket or flange. In the first case, elastic seals should be used, which are most often used in the arrangement of free-flow sewer pipeline systems. As for the fitting, or in these two cases, fasteners are used.

If you are faced with the question of how to properly connect HDPE pipes, you should become more familiar with the features of using couplings. These parts are elements of polyethylene, and extrusion technology is used in their manufacture. This method eliminates the use of welding machines and does not involve the purchase of expensive equipment. As practice shows, couplings are cheap, and their use allows saving on construction.

Why else should you use clutches

Couplings are quite common when connecting polyethylene pipes for the reason that they have a long service life, which reaches several decades. As a result, it is possible to obtain the most reliable fastening, which is resistant to aggressive environments. The coupling has a wide area of use and can be used for arranging pipelines for almost any purpose.

Use of fittings

Novice craftsmen often wonder how to properly connect HDPE pipes with fittings. When carrying out such work, certain rules must be followed. They provide for the need to disassemble the compression fitting by unscrewing. The pipe must be cleaned of dirt, and a chamfer must be made at its end. To do this, you need to use a beveler, but in the absence of this tool, you can use a sharp knife. If you are faced with the task of how to connect pipes with HDPE fittings, then you need to make a mark on the product with a marker, which will determine the depth of entry into the fitting. Before introducing the part, the pipe must be moistened with liquid soap. Next, the introduction is carried out, and when performing this action, you will have to make an effort, since the rubber seal creates a certain resistance. At the final stage, the fitting nut is tightened. In this case, it is important not to overdo it so that the connection is not overtightened.

Connecting a plastic pipe to a metal

If it is necessary to lengthen an old metal pipeline, it often becomes necessary to connect it to a polyethylene product. To do this, prepare two sliding keys, tow or Teflon tape. You will need an adapter with one end in the form of a metal product, and the other end should be in the form of a socket for a movable connection of a plastic pipe. If you are faced with the question of how to connect a HDPE pipe to a metal one, then at the first stage it is necessary to unscrew the pipeline coupling in the place where the connection is planned.

One needs to hold the coupling, and the other - the pipe. If it is not possible to unscrew the connection, an oil with increased penetration can be used. The next step is to use a plastic pipe tool and seal the threaded connection. This will prevent leakage later on. On the pipe, clockwise, several turns of the tape should be made, closing the thread. If you are thinking about how to connect a HDPE pipe to a steel pipe, then at the final stage you need to install and tighten the adapter. The connection is tightened until you feel resistance. It is not recommended to screw fittings with PVC female threads onto metal, as these two materials have different thermal expansion.

Connection of a polyethylene pipe with a faucet

The most popular method of joining a polyethylene pipe with a ball valve is butt welding. It should be carried out using a special installation in which both edges of the workpieces to be welded are fastened. The surface is cleaned of dirt and degreased. The heating element will increase the temperature of the edge of the polyethylene pipe to a viscous state, while the mechanism of the apparatus will help strengthen the elements to each other. After it was possible to connect the HDPE pipe to the faucet, it is necessary to leave the elements to cool completely. If the work is carried out correctly, the welded joint will look like an even seam of the same height around the entire circumference.