Do-it-yourself installation of metal-plastic pipes: connection technology and wiring examples

Pipes made from a symbiosis of metal and plastic are produced for the construction of intra-house highways.The new products made it possible to assemble a water supply and heating system yourself, without involving plumbers. Pipelines serve for a long time, are installed extremely simply and quickly, without creating problems even for inexperienced craftsmen.

By installing metal-plastic pipes yourself, you can save a lot of money, preserving the family budget for more important expenses. To install them, a home craftsman only needs to stock up on an easy-to-use tool, patience and knowledge, which we are ready to share with site visitors.

We will tell you everything about the specifics of using metal-plastic products and methods of connecting pipelines assembled from them. The article describes in detail the negative and positive aspects of their use. Here you will learn how to install trouble-free systems.

Features of metal-plastic products

Metal-plastic (metal-polymer pipes) are composite products for the production of which various types of materials are used. Such elements have an attractive appearance, good wear resistance, elasticity, and strength.

Metal-plastic pipes are distinguished by high consumer qualities (strength, flexibility, resistance to high temperatures and aggressive substances), as well as an aesthetic appearance

Typically, a pipe consists of five layers. A durable polymer, usually cross-linked polyethylene, is used as a supporting base. It makes the inner surface smooth, protecting it from blockages, and also contributes to the strength of the product.

An adhesive is applied to the core, on which aluminum foil that stabilizes the pipe is attached (it also prevents the ingress of oxygen). The connection is secured by butt or overlap welding.

The design of a metal-plastic pipe involves the use of five layers of different materials: two layers of polyethylene, two layers of glue, a layer of aluminum foil

The fourth layer is also applied with glue, to which the outer covering is connected - white polyethylene, which provides protection to the product and gives it an aesthetic appearance.

Technical characteristics of pipes D 16-20 mm

Here are the data typical for metal-plastic pipes of common diameters (16 and 20 mm):

• The wall thickness is 2 and 2.25 millimeters, respectively; The thickness of the aluminum layer is 0.2 and 0.24 mm.
• One running meter weighs 115 and 170 grams and holds a volume of liquid equal to 1.113 and 0.201 liters.
• The thermal conductivity coefficient is 0.43 W/m K, the expansion rate of metal-plastic is 0.26x10⁴ per 1 degree Celsius, roughness coefficient - 0.07.
• When the material breaks transversely, the strength coefficient is 2880 N.
• The strength of the connection between the adhesive layer and the foil is 70 N/10 sq. mm, the strength coefficient of the aluminum welded layer is 57 N/sq. mm.
• Metal-plastic pipes can work even at +95^O C, briefly maintaining temperatures +110-130^O WITH.
• Within temperature limits from 0 to +25^O The system operates at pressures up to 25 bar, and at +95^O C withstands pressure of 10 bar.
• The tightness and integrity of the metal-plastic pipe is violated under a load of 94 bar (at +20^O WITH).

With proper installation and compliance with operating rules, products made of metal-polymers can last 50 years or more.

Advantages and disadvantages of metal polymers

The advantages of such products include:

• ease of installation: connections of various categories of metal-plastic pipes are carried out quickly and easily;
• high heat resistance (water heated to 100°C can be transported);
• reasonable price (metal-polymer pipes are cheaper than metal and most plastic analogues);
• high strength and ring stiffness;
• resistance to corrosion and aggressive environments;
• reluctance to form deposits and blockages;
• aesthetic appearance;
• high throughput;
• low thermal conductivity;
• sufficient plasticity;
• possibility of easy repair;
• durability.

The main disadvantage of such products lies in the fact that the metal and plastic from which the pipes are made have different expansion rates. Regular temperature changes of the agent in the pipes can lead to weakening of the fastenings, which causes leaks in the structure.

To avoid this, experts advise, when performing installation, to always provide a certain margin at pipe joints. It will also be useful because metal-plastic systems do not withstand water hammer well.

It is easier and easier to evaluate the pros and cons of these pipes in comparison metal-plastic and polypropylene products. For a comparative review, see our recommended article.

Areas of application of metal-plastic elements

Pipes made of metal polymers are widely used in the construction of individual houses, in industrial construction and agriculture.

The main areas of their use are:

• transportation of liquids, gaseous agents;
• laying drainage systems, water pipes, heating;
• in structures involving the transfer of compressed air;
• supplying heating components to radiators, installing heated floors;
• installation of air conditioning circuits;
• protection and shielding of wires (primarily power);
• construction of irrigation systems.

Metal-plastic is not recommended for use:

• when organizing central heating systems with the proposed construction of elevator units;
• in places with an assigned fire safety level “G”;
• with the expected supply of hot liquid in the pipeline with a working pressure >10 bar;
• in rooms where it is planned to place sources of thermal radiation with a surface temperature of over 150 degrees C.

In addition, it is undesirable to use metal-polymer pipes in safety, signal, overflow, expansion circuits and in fire-fighting water supply systems.

Metal-plastic products are widely used in private and industrial construction. This photo shows pipes used for laying heating systems

Three main methods of pipe routing

The wiring of metal-plastic systems can be carried out using different methods, each of which is selected based on the feasibility and possibilities of further access to the system.

Option #1: hidden

In this case, all pipes and connections are hidden deep in the wall under the finishing materials. Only fittings and bends for connecting plumbing fixtures are exposed outside.

The hidden installation method involves installing the structure in the wall, where recesses are specially prepared for pipes, after which the surface is sealed

When using this installation method, the interior design is preserved, in addition, masking communications protects them from accidental damage.

This option has several disadvantages:

• Laying channels for pipes requires a complex and labor-intensive gating process. After laying communications, the surface must be restored again.
• This method is not suitable for load-bearing walls, where gating is prohibited by regulatory documents.
• Quite a high cost associated with additional work.

This method is best used when renovating a bathroom. It is not advisable to install a hidden installation in an already decorated room, since this will require complete dismantling of the wall covering (cladding, plaster).

Option #2: open

If for some reason the pipes cannot be hidden in the wall, they can be laid along its surface. This option is more convenient for visual inspection of joints, which allows, if necessary, to quickly clean the area or replace a component.

With the open method, pipes are laid along the surface of the wall, which allows for control of connections and reduces the cost of work

Open wiring can be used in rooms that have already been renovated, since the installation will not harm the design of the walls. The advantages of this method include its ease and lower cost of work than when laying internal communications.

Option #3: combined

In this case, the pipes are laid along the surface of the unfinished walls, after which they are covered with boxes or false panels. This is a rather complex method, since it requires the perfect fit of decorative elements into the interior, which can also be used as drywall, tiles and other materials.

Wiring diagrams for bathrooms and bathrooms

For plumbing work carried out in bathrooms and toilets, three layouts of metal-plastic pipes can be used. For private houses, the most rational option is to use a collector.

Efficient collector system

A reliable and practical option that involves connecting each object to a central pipe through a supply pair. This allows the faucet to regulate or turn off the water supply to each specific plumbing fixture.

With parallel wiring, each plumbing fixture is equipped with its own water line and its own shut-off valve. All branches come out of one device - the collector

All control devices are located in a compact manifold, which is placed in a space specially designated for them (cabinet).

Supply pipes with a minimum of connections do not require special control, which allows for hidden installation. The disadvantage of this option is the rather high cost, since for each connection you will need to purchase a special shut-off valve. Since such a system is quite complex, work must be done carefully and carefully.

In collector water distribution, control devices and shut-off devices are installed on the pipe supplying water to the collector

An important advantage: if a separate item (washing machine, faucet) fails, there is no need to completely disconnect the bathroom from the water supply - just turn off the necessary shut-off valve.

Serial connection system

This option involves connecting each plumbing item to the main pipe using a separate tee. It is more suitable for bathrooms with a minimum number of objects (washing machine, common faucet).

Sequential wiring, shown schematically in the figure, is recommended for use in rooms with a small number of objects that are alternately connected to pipes using tees

A sequential scheme can be implemented after finishing work has been completed in the room, using an open laying system. The assembly process is quite simple: the pipe is laid from one object to another, and at the same time the supply element is removed from the tee.

This option requires minimal financial costs. It should be taken into account that if there are a large number of liquid intake points, the pressure may not be enough, and the system will function with difficulty or even fail completely.

Wiring system with pass-through sockets

The connection of plumbing fixtures is similar to the serial one, but instead of tees, sockets are used. This scheme is usually used only in individual houses, since it requires laying long pipes, as well as installing an additional pump that will help provide the required water pressure.

When performing connecting work with metal-plastic pipes, several important nuances should be taken into account:

• When developing a design, it is desirable to provide a minimum of connections.
• It is important to use pipe and couplings made from the same material.
• It is better to use thermal insulation for the pipeline to prevent condensation from settling.
• It is necessary to provide free access to metering devices, filters, and detachable connections.

Compliance with the rules will allow you to create a reliable system that can last for many years.

Layout of sewer pipes

The work of installing sewer metal-plastic pipes has its own characteristics.

Sewer distribution made of metal-plastic has a number of features. In this case, it is important to use pipes of larger diameter, and also take measures to organize the slope of the pipeline

In this case, to ensure smooth drainage of wastewater and prevent blockages, it is important to comply with the following requirements:

• Maintain a slope (0.02-0.03 of the entire length of the structure) towards the drain manifold.
• It is prohibited to install bends at an angle of 90 degrees when installing structures.
• The need to install special tees with removable covers (revisions) in areas before turns that are prone to blockages.
• When installing the system in a hidden way, it is important to leave viewing windows opposite the revision.
• When assembling a system, it is important to leave a reserve intended for thermal expansion of the product.

For sewer installation, it is necessary to use pipes whose diameter ensures easy passage of wastewater.

For toilets, it is recommended to use products with a diameter of at least 100 mm; for bathtubs and sinks, 50-75 mm is sufficient.

Rules for installation of metal-polymer structures

When laying metal-plastic systems, it is important to be guided by the following provisions:

• When laying hidden pipelines from this material, it is important to provide removable shields (hatches) that are free of sharp protrusions. They provide access to compression fittings.
• It is important to lay systems through building structures using sleeves whose internal diameter is 0.5-1 cm larger than that of the pipe. The gap that forms between the elements must be filled with soft, non-flammable material that allows the pipe to move in the longitudinal direction.
• When laying metal-plastic plumbing or heating systems, it is important to avoid damage to the surface of the elements, including scratches or cuts. To unpack the bay, it is better to avoid sharp objects and mark the structure with a pencil or marker.
• Installation of the structure can be carried out using a support or suspension, which are usually present in the range of manufacturers of metal-polymer pipes. They help to attach products to the wall, while metal parts are installed with spacers made of soft material.

All stages of operations must be carried out carefully and carefully, since metal-plastic elements are sensitive to ultraviolet radiation and mechanical damage. External installation of such structures is appropriate only in places where there are no such factors.

Tools and materials for laying pipes

Laying metal-polymer systems requires a minimum of devices and materials, but it is better to choose high-quality devices and pipes.

Pipeline installation accessories

To create a structure made of metal-plastic, a very modest set of tools is enough: a pipe cutter, a simple pipe bender, press jaws, sliding and ring wrenches.

To install a metal-plastic system with your own hands, you need a minimum of tools, which can be purchased in a set or separately from a construction supermarket.

To separate measured pipe sections from the coil, it is advisable to stock up pipe cutter, designed for cutting metal-plastic pipes. Since metal-plastic is a fairly malleable material, it can be cut with a hacksaw or even a sharp knife.

However, ideal perpendicularity of the lines, without which it is difficult to obtain a tight connection, can only be achieved by using a special cutter.

Different types of wrenches are important for installing and assembling threaded connections on pipeline fittings. If absolutely necessary, you can get by with one spanner, but for comfortable work it is better to use two spanners and one adjustable wrench.

A gauge is an important tool for creating an accurate and tight connection between a pipe and a fitting: it allows you to center the cut plane and chamfer the inside of the product.

The pipe bender allows you to change the configuration of the element, so you can save on corner fittings. It is especially important to have this tool if the design involves a large number of angular mates.

Before starting work, we advise you to familiarize yourself with the rules and specifics crimping of metal-plastic pipes.

What materials will be needed?

To lay the pipeline, it is important to stock up on the following components:

• pipes (coils, measured sections);
• various fitting options (bends, tees, corners), with the help of which individual sections of pipes are transformed into a single system;
• fastening elements - dismountable clamps and clips, with the help of which metal-plastic structures are fixed to supporting surfaces, most often on the wall.

It is important to select all the necessary materials and tools in advance so that you can carry out all the work smoothly.

Will familiarize you with the range of metal-plastic products for pipeline assembly This article.

Pipe line marking

Before starting work, it is important to think about how the pipes will be placed.

When developing a scheme, it is advisable to:

• Draw pipeline lines directly on the walls of the room where it is planned to be laid, which helps visualize the structure.
• As a starting point, use the connection point of the pipe to the tap or radiator, which must already be installed before installation begins.
• Minimize the number of tees and crosses that affect pressure stability, and also minimize the number of other fittings.
• For corner laying of metal-plastic pipes, you can use a pipe bender or corner fittings.
• All connecting elements should be provided with free access, since threaded fasteners need periodic tightening to avoid leaks.

The installation of connecting elements must be carried out after completion of calculations and marking of the structure.

Overview of fittings for metal-plastic systems

To prepare for work, it is important to cut the pipes into sections of the required length, and all cuts must be made strictly at right angles.If the pipe becomes deformed during the cutting process, it must be leveled with a gauge (it will also help remove the internal chamfer).

To connect metal-plastic pipes of different categories into a single structure, connecting elements are used - fittings that differ in design, size and fastening methods

For installation of the structure, various types of fasteners - fittings, let's look at them separately.

Option #1: collet

Push-in fittings, consisting of a body, a ferrule, and a rubber gasket, have a detachable design, so they can be used several times. The thread of the parts allows them to be combined with household appliances.

To connect the connecting elements to the pipe, you need to put a nut and a ring in series. Insert the resulting structure into the fitting and tighten the nut. To make it easier for the pipe to pass into the connecting element, it is advisable to wet it.

Option #2: compression

Widely used for connecting pipes are parts that can be called conditionally detachable. Before installation, it is important to ensure the presence of o-rings and dielectric gaskets, which should be located on the shank of the part.

Compression fittings are widely used in the construction of metal-plastic structures. They allow you to easily create connections without the use of special tools

To connect, a nut and a ferrule are put on the end of the pipe (if it has the shape of a cone, then the process is carried out on the narrower side of the part). After this, the shank is inserted into the pipe (this requires some effort), and in order to seal, the part is covered with tow, flax, and sealant.

The next step is to put the union nut on the fitting body and tighten it.It is convenient to do this with the help of two keys: one of them fixes the part, the other tightens the nut.

This method is quite easy and does not require the use of special equipment, however, it is not advisable to use it for hidden wiring, since it requires checking the connection.

Option #3: push fittings

Convenient connecting elements that do not require special tools for fastening. For installation, it is enough to insert the product into the connecting part, and the end of the pipe should be visible in the inspection window.

Immediately upon completion of installation, thanks to the included water jet, the fitting wedge is pushed forward, forming a clamp that prevents leakage.

This method allows you to quickly and easily create the required structure, ensuring high-quality, durable connections. Almost the only drawback of push fittings is their high cost.

Option #4: press fittings

These elements are used to create permanent connections using press jaws or similar devices.

Press fittings create tight, long-lasting connections, but can only be used once. In addition, to work with such elements you will need press pliers.

For connections via press fittings you need to calibrate the part by removing the fez from it, after which the sleeve is put on it and the fitting is inserted. The sleeve is grabbed by press jaws, after which the part is firmly clamped by bringing the handle together.

This element can only be used once, but the fasteners mounted with it are quite tight and reliable, making them suitable for hidden wiring.

Installation of press fittings is carried out in the following order:

Installation of pipes from different types of materials

To connect elements, one of which is made of metal and the other of metal-plastic, special fittings are designed, one end of which is equipped with a thread, and the other with a socket.

For installation, a metal pipe needs to be threaded, wrapped in tow, lubricated with soap or silicone, and then the fitting is put on by hand. After its second end is connected to the plastic element, the thread is completely tightened using a wrench.

Assortment of fittings of different shapes

For ease of installation, the connecting elements can have different shapes. The most common are:

• adapters for connecting pipes with different diameters;
• tees providing branches from the central pipe;
• corners for changing the direction of flow;
• water sockets (installation elbows);
• crosspieces that allow you to organize different flow directions for 4 pipes.

Press fittings can have a special configuration (couplings, triangles, tees).

Conclusions and useful video on the topic

In the video below, plumbers will tell you how to correctly and quickly install structures made of metal-plastic pipes:

Using the right methods and quality components allows you to create durable metal-plastic systems that will last for a long time without leaks, repairs or unnecessary material waste.

You can talk about how you installed and connected metal-plastic pipes in the block below. Please comment on the information we provide. Ask questions, share useful information and thematic photographs.