More recently, in the construction and housing and communal services, a steel pipe with a diameter of 20 mm was used to conduct water supply inside buildings and structures. Today she has a serious competitor - a plastic pipe. By strength characteristics, it is not inferior to steel. Plastic is not afraid of water, salt deposits and deposits are not formed on the internal surfaces, due to which the inner diameter of the products decreases. However, the steel pipe is still in good standing, especially when it is necessary to conduct water supply in areas subjected to various active loads.
20 mm steel pipe
Bore inner diameter - 20 mm, outer - 26.8 mm. There is a classification in which the main parameter is the wall thickness. There are three categories:
- light with a wall thickness of 2.5 mm;
- ordinary - 2.8;
- reinforced - 3.2.
The manufacturing technology of this type of product is welding. To do this, the steel strip is rolled into a cylinder, the edges of which are welded together. Such a pipe easily tolerates high pressure, high temperatures, and copes with high mechanical loads. The coefficient of linear expansion is minimal. Fittings are not required for connecting pipes; rodents cannot damage them. One meter costs 130 rubles.
Plastic pipes
Plastic pipe products on the market are represented by a small assortment based on the material of manufacture: polyvinyl chloride (PVC), low-pressure polyethylene (HDPE), polypropylene (PP or PP), cross-linked polyethylene (PEX), metal plastic (PEX-AL-PEX).
Polyvinyl chloride
These pipes are not particularly popular. They tolerate various loads, even chemical ones, but there is one drawback - the complicated method of connection. To do this, use couplings or cold welding (using a special adhesive).
With adhesive bonding, the ends of the pipes are cut strictly perpendicular to the axis of the product, cleaned with sandpaper and degreased with acetone. Apply glue and press two joined ends to each other. In this position, hold the connection for at least 1 minute. After connection, the areas are cleaned of glue.
There are PVC pipes of 20 mm in the range of 190-200 rubles per 1 m.
Polyethylene
Products on the market are available in two versions: high and low pressure. The first with a diameter of 20 mm are not available. They have a low density, and therefore low strength. HDPE pipes are flexible, so they are recommended for use in areas with high seismicity.
The flexibility of the material makes it possible to carry out water supply in some areas without additional fittings.
The color of the pipes is black, some manufacturers put blue stripes on them, thus indicating that these products can only be installed in cold water systems. Hot water softens the polyethylene, which leads to ruptures, especially at the joints of adjacent elements.
Technical characteristics of HDPE pipes with a diameter of 20 mm:
| Characteristic | Index |
| Wall thickness mm | 2,0-2,3 |
| Maximum water pressure, MPa | 1,25-1,6 |
| Weight 1 lm, kg | 0,12 |
A low modulus of elasticity creates conditions under which a water hammer cannot occur. Frost resistance of low pressure polyethylene is high. Such pipes do not burst even in severe frost. Connection methods - welding or couplings. More often use the second as the simplest and less costly.
The price for one meter of HDPE pipe with a diameter of 20 mm is 17 rubles.
Crosslinked Polyethylene
The most flexible pipe goes on sale in bays of 100 m. Use not only for cold water supply. The material easily tolerates high temperatures, so the products are used for laying hot water and heating systems.
Specifications:
| Characteristics | Indicators |
| Outer diameter mm | 20 |
| Inner mm | 16 |
| Weight 1 lm, kg | 0,122 |
| The volume of liquid in 1 pm, l | 0,2 |
| Working pressure, MPa | 6-10 |
| The most admissible temperature, ° C | +95 |
| Minimum bending radius, mm | 100 |
| Service life, years | 50 |
Pipe sections are connected using press fittings or crimp couplings. Such a pipe costs an average of 75 rubles per square meter.
Polypropylene
The polymer is thermoplastic, has high strength and heat resistance. It is neutral to almost all chemically active components: acids, alkalis, a wide range of salts.
Polypropylene pipes are represented on the market in two versions:
- simple;
- reinforced.
Inside the reinforced products there is a framework made of aluminum foil, aluminum mesh (braid), fiberglass or composite material, which includes polypropylene, fiber and fiberglass.
Simple pipes made of pure polymer are specifically labeled PN. Manufacturers offer brands that differ from each other in the working pressure of the flowing water. For cold water supply, 20 mm PN10 pipes suitable for water pressure of 1.0 MPa are suitable. Manufacturers apply blue lines to their surface.
If a pipe is required for hot water supply or for a heating system, it is better to use PN20 or 25. Red stripes are applied to them. Plastic pipes of this type are characterized by increased rigidity. You can bend them, but the bending radius is large. Therefore, fittings of various configurations and designs are used in the installation process. The connection method is welding.
Specifications vary by product brand. Service life depending on the temperature of the liquid and its pressure:
- PN10. If the water temperature does not exceed 20 ° C and the pressure is 1.3 MPa, such a pipe will last up to 10 years. Reducing the pressure to 1 MPa increases the life of up to 50 years.
- PN25. The service life increases from 10 to 50 years if, at a temperature of + 20 ° C, the pressure drops from 3.4 to 3.2 MPa.
With increasing temperature, the service life decreases. The same goes for pressure.
The cost of a plastic pipe made of polypropylene for water supply with a diameter of 20 mm also depends on the brand of pipes. The average price for 1 pm PN10 is 17 rubles, PN16 is 21 rubles. The same PN16, only reinforced, costs 55 rubles.
Plastic pipes with a diameter of 20 mm
The product consists of five layers:
- outer - cross-linked polyethylene;
- the third is aluminum foil;
- between them is an adhesive composition that fastens the foil and the outer polymer braid;
- another layer of cross-linked polyethylene;
- between them the adhesive composition.
This is a flexible product that goes on sale in bays, the length of the material is 100 m. The outer diameter is 20 mm, the inner is 16 mm, and the wall thickness is 2 mm. Other features:
| Characteristics | Indicators |
| Minimum bending radius, cm | 6 |
| Maximum temperature, ° С | +95 |
| Maximum pressure, MPa | 1 |
| Thermal conductivity, W / m K | 0,43 |
| Linear expansion,% | 0,81 |
| Weight 1 lm, kg | 0,143 |
| Volume 1 lm, liter | 0,2 |
The price of a metal-plastic pipe is within 70 rubles / m. Usually they are installed in a system of "warm floors", rarely in a water supply system, because other plastic pipes are cheaper.
