The DVN-Stroy company performs laying work polyethylene pipes various diameters, from 50 to 630mm.

Polyethylene pipes found wide application in construction. They are used in the laying of water supply networks, gas distribution systems, pressure and gravity sewer networks, as protective cases for electrical and telephone cables. Pipe laying is traditional open way or trenchless method. The production of PE pipes is carried out by the method of continuous extrusion from polyethylene low pressure.

The DVN-Stroy company uses only. For pipes with a diameter of up to 315mm, the Italian device GF Omicron 315 is used. For pipes 315-630mm - Ritmo Delta 630. Socket welding is performed using the Hurner HST300 device.

Installation methods for polyethylene pipes.

Polyethylene pipes are mounted mainly in three ways: using butt welding, electrofusion welding with embedded heaters and using compression fittings. Pipe turns and branchings are carried out using welded or cast fittings: bends, crosses, tees, bushings for flanges.

Remoteness of the object;

The presence or absence of electricity, etc.

The cost of the work is estimated after reviewing the project documentation or a specialist's visit to the facility.

You can also send drawings or a piping diagram to email [email protected] This will allow us to more accurately estimate the cost of work and materials (polyethylene pipes, bends, fittings, tees, gate valves or ball valves, bushings, flanges, electrical couplings), estimate the timing of the work.

An example of the installation of polyethylene pipes for water supply.

Most urban utilities built in the Soviet era are worn out by 70% or more. Almost all water supply pipelines were made of steel pipes which are most susceptible to corrosion. The deterioration of these pipes is expressed in constant emergency situations - pipe breaks, a decrease in the pipe cross-section and its throughput, water pollution in terms of biological parameters.

The figure below clearly shows the state of the steel water pipe after a long service life.

One of the options for the reconstruction of worn out is the laying of polyethylene pipes. Pipes can be replaced old pipe, with destruction, or be laid next to an existing pipe, without stopping the water supply to residential buildings and other consumers. Wells and chambers, depending on the condition, are subject to replacement, complete or partial reconstruction (for example, replacement of necks, stairs and hatches).

At the first stage, after excavation of trenches and pits, polyethylene pipes are welded into a whip by butt welding, in a trench or on the surface of the earth.

Installation of polyethylene pipes are performed in the following sequence.

1. Pipes are aligned and centered relative to each other as much as possible. Pipe surfaces are prepared for installation: they are cleaned of dirt and degreased.

2. Tapping into the main pipe can be done in several ways, for example, using a TF flanged cast iron tee or a plastic tee. The figure below shows a tie-in option using a saddle. HDPE bushings with boring flanges are mounted on the ends of the pipes with the help of electric couplings.

It is very important to correctly mount the assembly on a free pipe. The distance between the flanges should be such that, when installing the valve and tightening the bolts, the connection would be sufficiently tight. In the future, the connection must withstand hydraulic tests of 8-12 atm, while the polyethylene pipes should not experience unnecessary tensile stresses, which will ensure a long service life of the laid water pipes.

3. Next, the flange valve is installed. All work is done in the existing chamber. After switching the water supply to a new line, the old worn out water pipes are subject to dismantling and washing with a cement-sand mortar.

The water supply from polyethylene pipes possesses high operational characteristics. Polyethylene has high chemical resistance, is not subject to corrosion and low temperatures. Due to the high smoothness of the pipe walls, their throughput is 25-30% higher than that of steel pipes.

Service life of polyethylene pipelines - not less than 50 years.

Rules for the laying and installation of polyethylene pipes.

While doing underground laying polyethylene pipes, the following rules must be remembered and observed. The depth of pipe laying should be 0.2 meters more than the depth of freezing of the earth (in the Moscow region it is 1.5 meters). The width of the trench along the bottom should be 40 centimeters larger than the diameter of the pipe being laid. If butt welding of HDPE pipes will be carried out in a trench, its width should allow the welding machine to be placed there.

Before installing the pipes, in order to avoid damage to them, the bottom of the trench must be carefully leveled. If the base of the trench has solid inclusions, it is necessary to arrange a sand cushion of sand 10-15 centimeters thick. If necessary, the device of the base and backfill is eliminated.

After pipe laying, backfilling is carried out. The initial sprinkling is done with sand, to a height of 15-30 centimeters above the top of the pipe. Further backfilling up to the top of the trench can be done with local soil of stones or construction debris larger than 20mm. Under the planned roads and driveways, the backfilling of the trench is carried out exclusively with sand with layer-by-layer compaction.

Advantages of polyethylene pipes.

Modern polyethylene pipes are made from polyethylene grade PE80 m PE100 according to GOST 18599-2001 and have a lot of advantages over other types of pipes:

The cost of polyethylene pipes is lower than steel pipes;

Service life not less than 50 years;

HDPE pipes are not subject to corrosion, and are also resistant to aggressive environments;

In view of the low weight, the installation of polyethylene pipes is carried out without the use of heavy-duty equipment;

Installation of polyethylene pipes by butt or electrofusion welding is simple and reliable;

When water freezes inside the pipe, it does not collapse;

These undeniable properties of polyethylene pipes have allowed them to be widely used in all areas of engineering communications construction.

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Construction of a pipeline from polyethylene pipes

Most of all pipelines laid in cities date back to the Soviet era. The deterioration of heating mains, sewerage, gas and water communications reaches 70%, which is due to the material from which the pipes are made. This is a steel that is subjected to intense corrosive attack. The construction of gas pipelines from polyethylene pipes is becoming more popular today. As the service life expires, many accidents occur on various pipelines: under high pressure pipes break, numerous leaks form, which lead to significant water losses. Performance indicators are deteriorating: due to a decrease in the cross-section of pipes, their throughput is reduced, water is polluted, and its biological indicators are reduced.

Advantages of polyethylene pipes

Pipes made of polyethylene (PE) are a modern alternative to their physically and morally obsolete metal predecessors. They have whole line indisputable advantages in comparison with products made of steel or cast iron.

1. The absence of corrosion damage, which minimizes the cost of installation, maintenance and repair.
2. Ease of use: Polyethylene products are easy to cut, so they can be easily adjusted to size both on the construction site and in the field when laying pipelines.
3. High throughput due to the fact that the inner walls of PE products are smooth.
4. Pipes made of polyethylene have an elastic structure of the inner walls, on which scale does not form as a result and they are not clogged from the inside with various suspensions contained in the liquid.
5. Polyethylene is chemically inert, successfully resists aggressive effects, therefore, it does not need additional special protection.
6. Polyethylene is not electrically conductive, so it is not afraid of stray currents that destroy metal pipes.
7. The bending radius of a polyethylene pipe can be up to 10 of its outer diameters, depending on temperature, which reduces the cost of connecting parts and facilitates the design and construction of pipelines.
8. Polyethylene pipe has high flexibility: the minimum bending radius is 25 pipe diameters at 200°C.
9. Significantly less weight than metal pipes which facilitates assembly and installation.
10. PE pipes are resistant to temperature changes and have high sanitary and hygienic characteristics.

Scheme of deformation of polyethylene pipes depending on the type of soil.

Important note. Freezing of the soil leads to the movement of pipelines in a vertical plane. These movements are uneven, resulting in deformations (bends). Prediction of these states should determine how much the bending radius of a polyethylene pipe depends on the level of temperature decrease. In order to determine the bending radius, it is necessary to make special calculations. Or refer to special tables, which indicate the minimum bending radius for a particular type of pipe.

The minimum bending radius of a polyethylene pipe is recommended by the manufacturer for each type and grade of pipe. If it is not possible to obtain the desired bending radius, then bends, tees, etc. should be used.

Due to their technological and operational characteristics, polyethylene pipes are widely used: they are used in the construction of new pipelines and in the repair of old communications that have served their time.

Scope of polyethylene pipes

Polyethylene products are widely used in modern construction.

They are used in the construction of water pipes, sewerage, gas pipelines. PE pipes are used in pressure and gravity sewerage, serve as protective cases for electrical and telephone wires.

With the help of polyethylene pipes, the reconstruction of old networks is carried out. Replacement can be carried out with the destruction of worn-out communications, but it is possible to lay new ones in parallel with the old ones, which does not require stopping the water supply to the population and blocking the sewerage system. Reconstruction of wells and other communication and plumbing structures depends on the degree of their deterioration. partial replacement individual parts may be subject (necks, shut-off valves etc.), if necessary overhaul with a complete replacement of pipelines.

Installation of polyethylene pipes for sewerage

Sewer networks are internal and external. Their purpose is to collect and transport sanitary and storm waste water, which has different chemical composition. Any sewer problems dramatically affect the quality of life.

Elements and assembly for polyethylene pipes internal sewerage

Polyethylene pipes for sewerage began to be produced not so long ago, and today they fully meet the high requirements due to their inertness to the effects of mineral acids, alkalis and other aggressive substances. PE sewer pipes have a large capacity due to the absence of internal roughness. When arranging external sewage systems, frost-resistant PE pipes are used. Installation of internal sewerage does not require pipes with such high performance characteristics.

Sewer pipes are attractive to specialists working on the arrangement of such systems in that their installation is much easier in comparison with traditional sewer networks. Installation of internal sewer communications using polyethylene pipes does not require complex special equipment. Small-diameter polyethylene pipes are mounted using compression fittings.

Equipment outdoor sewerage produced by butt welding: special welding equipment allows installation, reducing the number of joints up to five times in comparison with metal sewer pipes

Connection of water polyethylene pipes

PE products are connected in three main ways:

1. butt welding,
2. socket welding with embedded electric heaters
3. installation with compression fittings.

A detachable connection is also possible, which is carried out by steel clamping flanges. Installation of bends and branches of pipelines is carried out using welded or cast fittings.

Different connection methods are used depending on the working conditions. If there are conditions for the placement of welding equipment, then butt welding is necessary. Butt welding is used when working with pipes of large diameters (from 630 mm).

The limited working space (wells, chambers, trenches) requires electrofusion welding using embedded heaters.

If it is necessary to connect pipes with a diameter of up to 63 mm, compression fittings are used, which creates detachable structures. This connection is easy to use, has high performance, does not require complex special equipment. Compound internal systems pipelines are most often carried out in this way. Their installation is available even to non-professionals.

Laying pipelines

Laying of polyethylene pipelines is carried out in two main ways. These are the traditional laying of pipes in an open trench and trenchless laying - a method of deep directional drilling.

Pipelines made of polyethylene with the open method are laid in a trench, the width of which is determined by the need to create conditions for work. Water supply and sewerage equipment requires a trench width of 40 cm more than the outer diameter of the pipeline. These parameters are most often specified in the project. Long-length polyethylene pipes are often laid in a trench dug with a narrow-reach chain excavator. In this case, the width of the trench decreases.

The trench must be properly prepared. Its arrangement depends on the condition of the soil. If the bottom of the trench is hard and dense, then a pillow device is necessary. The bottom is covered with a layer (about 10-15 cm) of sand or other granular material and leveled. At a distance of 2 meters from the manhole, the pillow is rammed. At the bottom there should be no stones, lumps of frozen soil. When working with loose soil, which has a risk of displacement, it is required to strengthen the bottom. In such cases, the bottom of the trench is reinforced with geotextiles.

With a flat trench bottom with optimal soil characteristics, a cushion is not needed. You can get by with a small excavation of the earth at the base of the pipe to its width and replace it with a softer one.

Trench backfilling

The soil excavated during the trenching, in which there are no stones of 20 mm in size, is used for the initial backfill. It is made for the entire length of the pipe, about 15 cm high from its top. If it is necessary to compact the backfill, the soil must meet certain requirements. Fine gravel (20-20 mm) or crushed stone (4-44 mm) can be used. Soil must not be dumped directly onto the pipeline. Laid to the bottom of the trench and sprinkled pipeline needs to be sealed. The backfilled soil is compacted in layers of 20 cm on both sides of the pipe so that it does not move. The soil is not compacted directly above the pipe.

Backfilling is carried out after compaction and obtaining a compacted layer of about 30 cm on top of the pipe. Backfilling of the trench can be done with excavated soil, the size of the largest stones is allowed no more than 300 mm. Even if there is a layer of protective backfilling with a thickness of about 30 cm, the size of the stones in the soil, which is used for backfilling, cannot be more than 60 mm.

Trenchless pipeline laying

In some cases, when pipeline lines intersect with a railway, a busy highway, a river, and other obstacles, laying an open trench is not possible. The reason may also be the need to minimize the cost of digging a trench. This is the basis for applying the method of trenchless laying of polyethylene pipelines. The method of trenchless laying of horizontally directional drilling (HDD method) has become widespread.

Horizontal drilling is a special way of arranging communications without opening the ground. Work begins at the point where the pipe is brought to the surface. Technology guarantees high precision the output of the drill in the proposed place of exit to the surface. The method allows laying underground pipes with a length of more than 100 m and a diameter of up to 630 mm or more. There are two main types of horizontal drilling: steerable and unsteered.

Controlled horizontal drilling is carried out by tunneling machines, through flushing and pilot drilling.

Unguided horizontal drilling is carried out by two methods: 1) without casing (ramming, displacement drilling, auger drilling) and 2) with casing (drilling injection, puncture drilling, impact drilling, ram drilling).

Horizontal drilling methods and trenchless laying of polyethylene pipes are considered the most modern technology. To expand the well, a special drilling extension is used. To improve the wiring, the well is treated with drilling mud, which forms and lubricates the channel itself.

Thus, the characteristics of polyethylene products make it possible to carry out their installation and laying using any currently known method, taking into account the limitations imposed by the minimum allowable radius of their bending.

A pulled or pushed polyethylene pipe is able to repeat the configuration of the old route, which has a radius of curvature of more than 120 diameters of the pipe itself. Metal products practically do not have such a bending radius.

Organization of installation work

Welding is carried out either according to the basic scheme, or by the route method. The basic method is used in cases where the object is located near the welding site, where the pipes are pre-connected, and then they are brought to the pipeline route in finished sections. The length of the section can reach more than 30 m. On the spot, they are welded into a single thread, which then carefully, so as not to violate the bending radius, must be laid in a trench.

Route welding starts along the trench. Then the installation and welding is carried out by mobile welding units. Pipes of small diameter can be laid manually in the trench. However, pipelayers or cranes are most often used. The finished thread should be lowered without jerks, evenly, having previously secured it with hemp ropes or soft slings, which should be located at a distance of 5-10 meters from each other. The solid welded string must be lowered into the trench carefully so that the critical bending radius is not exceeded during the laying process. Beforehand, you should wait at least 2 hours after welding the last link.

Disadvantages of polyethylene pipes

Problems with polyethylene products are associated with the characteristics of all viscoelastic thermoplastics. Their strength largely depends on the degree of bending and compression, and in general it is relatively small. Polyethylene is sensitive to ultraviolet light, which has to be compensated for with coloring additives (usually soot) and the use of a protective color. The thermal expansion of polyethylene is quite high and it has to be compensated with the help of a constructive L- or U-shaped bend of the pipe.

Today, domestic underground pipelines have a length of about 2 million km. Basically, these are steel pipelines. The share of polyethylene pipes accounts for, for example, about 10% of the entire length of gas pipelines. Other networks also have not very high rates for this parameter. However, there is a strong trend towards the fact that modern pipelines are changing in percentage terms in favor of polyethylene pipes.

They are used in systems whose maximum working pressure is not more than 0.16 MPa.

Low pressure polyethylene pipes are simple and easy to install.

Not so long ago, pipes made of various materials. Along with asbestos-cement products, non-pressure reinforced concrete products were also actively used.

But this area of ​​water supply and sewerage began to be actively conquered by non-pressure polyethylene pipes.

The main factors that significantly influence the choice of low-pressure polyethylene pipes are their highest performance:

• no corrosion;
• excellent resistance to various chemicals;
• long service life;
• simplicity and ease of installation;
• relatively low cost.

For water supply and sewerage, three varieties are produced:

• non-pressure smooth HDPE pipe;
• non-pressure corrugated HDPE polyethylene pipe;
• spiral wound non-pressure pipe.

Non-pressure smooth pipe

Connection of a non-pressure smooth pipe with clamp fittings.

Smooth non-pressure polyethylene pipes are orange in color and are produced in the following sizes:

• diameter from 20 to 560 mm;
• length from 500 to 1300 mm.

Types of products based on the ring stiffness class:

• SN2 - installation depth no more than 1 meter;
• SN4 - installation depth no more than 6 meters;

Installation of this product is carried out in a socket. One side of the HDPE pipe has a socket in which it is located. Sewerage installation is very simple, for this you need to insert one product into the socket of another. If it is necessary to connect elements with different diameters, there are special adapters for this. For ease of installation, various tees, couplings and angles are provided.

It also doesn't cause problems. Fastening to the ceiling or wall is carried out using the simplest latches (clamps), which are fastened with screws to the wall or ceiling.

Corrugated non-pressure pipes

Sewerage installation is very simple, for this you need to insert one product into the socket of another.

This type of HDPE pipes is also used for sewerage and drainage systems. This type of non-pressure pipes can be made from polyethylene, polypropylene, and combinations thereof.

Polyethylene pipes of this type have differences in design and production technology. These products are produced in a two-layer version and have a smooth inner surface and a corrugated outer surface. The outer wall of the product, which has a black color, guarantees high protection against ultraviolet radiation, it also serves to provide the necessary ring rigidity of the HDPE pipe and its resistance to deformation. White color, which has inner wall, facilitates visual diagnostics of the sewer system.

This product is available in the following ring stiffness classes:

• SN4 - installation depth no more than 4 meters;
• SN6 - installation depth no more than 6 meters;
• SN8 - installation depth no more than 8 meters;
• SN16 - installation depth no more than 16 meters.

Produced in sizes:

• diameter - from 110 to 1200 mm;
• length - 6 or 13 m;
• profile width - from 6 to 41 mm;
• wall thickness - from 1.2 to 5 mm.

Here are some positive factors:

A rubber gasket is installed inside the corrugation, which prevents its displacement during installation.

1. High impact resistance (even at low operating temperatures).
2. Good chemical and mechanical resistance.
3. High ring stiffness as a result of the use of special grades of polyethylene in the production and optimal design.
4. Ease of installation: the connection is made with a rubber gasket (o-ring) and a socket or butt welding. A rubber gasket is installed inside the corrugation, which prevents its displacement during installation. Due to its special shape, the rubber gasket prevents not only leakage from the product, but also the ingress of ground water into it.
5. High versatility, due to the possibility of using a wide range of fittings, which allows you to connect to any type of pipe.
6. The light weight of the product makes it convenient to store, mount and transport.
7. The excellent flexibility of the product makes it possible to bypass various obstacles when laying the piping system without much difficulty.
8. Long service life at low cost of operation.
9. Excellent value for money.

Features of installation and installation

For pipes with a diameter of 250-1200 mm, the sealing ring is inserted into the groove of the first corrugation.

This product is designed for underground installation with a maximum depth of up to 16 m and a minimum depth of at least 1 m. It is very important to choose the right backfill material for the formed trench. The granulometric composition of this material should densely fill corrugated products, that is, the particle size should not exceed the width of the profile.

Connection using a sealing ring and a coupling is carried out as follows: for a product that has a diameter of 250 to 1200 mm, install the sealing ring in the groove of the first corrugation. For a product that has a diameter of 110 to 200 mm, into the groove of the second corrugation. After that, we install the coupling, while the force must be constant and equally distributed.

One of the important advantages of corrugated non-pressure pipes is that they can be joined by butt welding. This became possible due to the sufficient wall thickness and the distance between the corrugations. Welding is a complex process that should only be carried out by an authorized and qualified person. However, it should be remembered that butt welding is used to seal pipes and cannot provide the same ring stiffness as a coupling.

Spiral non-pressure pipes

Due to the geometric shape of the pipe wall profile, helical pipes have the highest resistance to deformation for free-flow networks.

A spiral non-pressure product is used for the construction of a non-pressure sewerage and drainage network, often with a large diameter (more than 1000 mm). This type of non-pressure pipe is made of polyethylene by winding a continuously produced profile onto a rotating drum. cylindrical shape with simultaneous welding of coils to each other. Due to the geometric shape of the pipe wall profile, it has the highest resistance to deformation.

This product has several types:

1. SPIROLINE has a ring stiffness of SN2, SN4, SN6, SN8, SN16, which allows it to be laid to a depth of up to 16 m. A wide range of internal diameters - from 500 to 2400 mm. The length of the segment is from 0.5 to 13.5 m.
2. KORSIS has a ring stiffness of SN4, SN8, which allows it to be laid to a depth of up to 8 m. The inner diameter is from 800 to 2400 mm. The length of the segment is from 0.5 to 13.5 m.
3. VEHOLIGHT has ring stiffness SN2, SN4, SN8. Inner diameter - from 280 to 800 mm and from 360 to 3000 mm. The length of the segment is from 0.5 to 13.5 meters.

The connection is made by directly screwing one product into another with further end welding. These polyethylene pipes can also be mounted using various fittings (branch, transition, tee, tank, well).

In order to form and install water supply and drainage networks, it is necessary, first of all, to use water channels made of polyethylene pipes, taking into account all the advantages of such water channels over steel or cast iron products. A significant drawback of pipes made of metal, especially for steel products, is their short service life due to exposure to corrosive processes.

When installing any piping system, its operating characteristics will be determined by how scrupulously and carefully the workers adhered to the technique of installing gutters, no matter what material they were made of - metal or plastic. Each type of pipe has its own rules and installation technologies. Laying pipelines from polyethylene pipes has significant differences. First, you need to measure the width of the trench. It should perfectly provide convenience during installation and installation of the pipeline. The main thing to consider: the width of the ditch should be approximately 40-50 cm larger than the diameter of the pipes. Such conditions must be met when laying sewer pipes and when laying water pipes. If the laying of drains is carried out in strong or dense soil, then it is imperative to arrange a sand embankment about 10 centimeters wide.

It is imperative to remove any stones from the bottom of the trench, and the bottom must be made smooth and even. Care should be taken to ensure that the ground at the bottom is not frozen. If the soil for laying the pipeline from polyethylene pipes is loose, then it may be necessary to apply technologies to create the effect of strengthening the earth. If there is a possibility of soil displacement, then in order to ensure the static position of water channels in the ground, geotextiles are laid out at the bottom of the ditch.

Most often, the installation of a pipeline made of polyethylene pipes begins with the laying of a special pillow, which is a certain material, namely gravel or sand. The thickness of such a pillow can be varied depending on the characteristics of the soil, but on average it is 10-15 centimeters. It is necessary to seal the pillow only in the vicinity of the manhole. In places where water channels are attached to each other, workers make pits. When, during the analysis of the soil, its ability to strong internal friction is clarified, in this case the pillow can not be laid. Then, at the base of the track, the hardened soil is removed, and softer soil is laid out in its place. The excavated soil can later be used to backfill the pipeline, but it must first be ensured that it does not contain large stones. You can also fill up the water supply pipe with sand or fine gravel. First, the pipe is backfilled along the entire perimeter, at a height of more than 15 cm from its extreme point. If you have to make the soil more dense, then backfilling is done in small layers of 20 centimeters. In no case should you compact the earth directly above the drain.

After installation pipeline made of polyethylene pipes backfilling is most often carried out with seized earth, but it is first necessary to clear it of stones if they exceed 6 cm in size, and if there are boulders, then 30 cm.

Pipes made of polyvinyl chloride are attached to each other most often with glue in the socket. Nevertheless, it must be borne in mind that for gluing it is required to carefully clean the surfaces and apply the adhesive base very carefully. The butt edges must not be bent. AT last years For installation and fastening of drains made of polyethylene materials, bell-shaped solderings have become very popular, which are sealed with rubber cuffs of various profiles. In such a case, drains are made with sockets that contain circular grooves inside. Attach if necessary polyethylene pipe to steel or cast iron, then flange connections must be used. Where they are laid sewer systems from polyethylene gutters through the walls of wells, fasteners with a single rubber ring are used as sleeves.

Welding is carried out mainly by the contact method, it is carried out in a socket or end-to-end with shaped compartments. When welding polyethylene pipes it is necessary to strictly observe and monitor the diameters of the drain and their circumference.