Plastic pipes are now very popular. They are used in private homes, apartments, industrial buildings and boiler rooms. Such products have gained immense popularity among urban residents for a reason, because they have several functions at once:
- pipes made of metal-plastic are able to conduct liquid heated to 110 degrees;
- they can be bent manually at the required angle without damaging the structure.
What explains the popularity of pipes from MP
Metal-plastic pipes consist of two materials - polyethylene and aluminum. They have become indispensable in those places where it is necessary to transport hot or cold water, gas, and liquids for heating homes.
Thanks to their incredible flexibility, modern pipes are easy to install, minimizing the use of welding and additional equipment (fittings). Thanks to such advantages, metal-plastic has become possible to use to solve a number of problems:
- installation of underfloor heating, aluminum and plastic pipes are used as heating;
- the pipeline can be hidden inside the walls;
- thanks to modern pipes, it has become incredibly convenient to make connections to radiators;
- at the dacha, pipes from MP are used for the installation of irrigation systems.
Production of modern pipes
Plastic pipes consist of a two-layer molecularly crosslinked polypropylene called PE-X. A thin aluminum substrate is laid between it. Connect all three layers using a specially designed adhesive. Each manufacturer seeks to use their individual composition of the adhesive.
Aluminum gives strength to pipes, and thanks to propylene, such plumbing equipment can be bent at an angle without much effort. A tape of aluminum of minimum thickness is made of two semicircular fragments. They connect end-to-end or overlap with each other. For reliable adhesion, welding is used using ultrasound. After this procedure, layers of polypropylene with an adhesive composition are applied from the outside and the inside.
After a reliable coupling of the pipe, it is necessary to mark and wind it up for easy transportation. It is in this form that they enter stores.
The technology of manufacturing MP pipes
The sectional design of such pipes can be described as follows:
- The outer layer is made of polyethylene.
- Glue.
- Non-ferrous metal foil.
- Glue again.
- The inner layer is made of polyethylene.
Thanks to this design, the service life of metal-plastic pipes in an apartment reaches several tens of years. White color of plastic pipes was not chosen by chance, because the coating looks aesthetically pleasing. In addition, there is no need to periodically tint the pipeline.
Two layers of polyethylene (inner and outer) provide a smooth inner surface, thanks to which water can freely flow into the sink. Scale does not remain on the walls of the pipeline and does not deposit. The outer protective layer performs the function of protecting the aluminum film during the joining of pipes with each other and with metal parts, preventing galvanic processes. Also, the plastic surface eliminates the formation of condensation. Due to this important property, the service life of plastic pipes increases significantly.
The design of pipes from MP has incorporated all the positive qualities of two materials - metal and plastic. Such plumbing products can now be widely used in water supply, sewage, air conditioning systems, and more. In addition, plastic is not susceptible to corrosion, so the service life of metal-plastic pipes significantly exceeds their predecessors, made without the use of polypropylene.
Polyethylene stably tolerates an aggressive environment, is able to withstand heating up to 110 degrees, while not emitting harmful, poisonous substances. The aluminum foil laid in modern pipes is not more than 400 microns thick and can withstand high pressure, which is important for the use of pipelines for sanitary purposes. Provided that it is used correctly, the manufacturer guarantees a service life of metal-plastic heating pipes of about 50 years without repair.
Scope of pipes from MP
In addition to water supply, sewage, and heating, plastic pipes with aluminum foil are used for the following purposes:
- long-distance transportation of compressed air;
- in air conditioning systems;
- for mounting an electric cable as protection against force fields and preventing a fire due to a short circuit;
- transportation of liquid and gaseous substances.
Despite the rather long service life of metal-plastic pipes and characteristics that allow them to be used not only in everyday life, but also in industry, they also have a number of limitations in operation:
- In the system of centralized heating of residential buildings, if there are elevator units.
- It is forbidden to use in premises of category "G" as fire protection.
- In piping systems where the pressure exceeds 10 bar.
- In places where the temperature of the heating pipe can exceed 150 degrees.
Sizes of pipes made of plastic and metal
With a rather long service life, plastic pipes for water supply are produced by both domestic and foreign manufacturers of various diameters (from 16 to 63 mm). Before installation, a pipe is selected, taking into account only the outer diameter.
As a rule, pipes with an outer diameter of 16 to 26 mm are used to install a water supply system in a private house or apartment. If the house has a large network for transporting water, then pipes of a larger diameter are used - 32 and 40 mm. In this case, the main line is constructed from pipes of a much larger diameter, but the connection to individual plumbing fixtures is carried out using pipes of a smaller external diameter.
How many pipes from MP serve
Plastic pipes with a service life exceeding metal by several times are also used at large industrial facilities, for example, in bays. The length of such structures reaches 200 meters. Designs can last several decades.
Advantages of plastic pipes
Hot water practically does not affect the service life of metal-plastic pipes. In addition, such designs have a number of other positive qualities:
- Complete environmental safety when used properly.
- High resistance to chemical influences.
- Long life without maintenance and repair.
- The pipe walls always remain clean, preventing plaque from settling on the inside.
- High throughput compared to metal predecessors.
- Light weight.
- Ability to bend.
- Almost non-waste use.
- A fairly simple installation that does not require knowledge and expensive tools.
- An opportunity to brick up pipes in cement or concrete, masking them in apartments and houses. Thus, not only an aesthetic appearance is preserved, but also space is saved in the room.
- In case of need of repair they are easily recoverable.
- Decent appearance.
- Low price.
- Sound absorbing properties.
- Does not accumulate static voltage.
- Low coefficient of thermal conductivity.
Negative factors in pipes from MP
But there is a significant drawback of such plumbing structures - the service life of the fitting on metal-plastic pipes is reduced with sudden changes in temperature. Leaks in the area of the pipe joints occur due to the fact that aluminum and plastic have different coefficients of thermal expansion. With sharp heating, aluminum expands more slowly, and when cooling, non-ferrous metal takes its original form much faster. Such a difference negatively affects the pipes from the MP, leaks often occur.
The service life of metal-plastic pipes for water supply does not change if they are bent. However, repeated bending of the material can lead to rupture of the aluminum film inside. It is allowed to bend the material up to a certain radius, not exceeding eight times the outer diameter of the product.
The long service life of metal-plastic pipes and their popularity is also explained by the fact that they can be bent by hands without applying much effort. To do this, it is necessary to fill the cavity of the product with sand and so bend it to the required state.
The manufacturer warns that bending plastic sanitary products and twisting about its axis is not allowed.
Characteristics of pipes from MP
The most popular are pipes whose outer diameter is 16 and 20 mm. Using their example, we consider the technical characteristics of metal and plastic products.
The pressure in the pipeline system depends on the diameter of the pipe, the thickness of the metal wall, as well as the water passing through it.
If the water in the pipes is heated to 95 degrees, then the pipe must be designed for a pressure of 10 bar. If the water temperature is 25 degrees, then the design in the water supply system must withstand 25 bar.
Plastic pipes with the addition of aluminum are able to withstand a large temperature, reaching up to 110 degrees, however, under one condition - such an increase should be short-term. At the same time, the strength of the metal-plastic product will not be compromised. Modern pipes will burst only if the internal pressure reaches 94 bar and the temperature of the liquid inside is about 20 degrees.