More recently, in the construction and housing and communal sectors, a steel pipe with a diameter of 20 mm was used to conduct water supply inside buildings and structures. Today it has a serious competitor - a plastic pipe. It is not inferior to steel in strength characteristics. Plastic is not afraid of water, salt deposits and deposits are not formed on the inner 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 install water supply in areas subject to various active loads.
Pipe 20 mm steel
Passage inner diameter - 20 mm, outer - 26.8 mm. There is a classification in which the main parameter is wall thickness. There are three categories:
- lightweight 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 up into a cylinder, the edges of which are welded together. Such a pipe easily withstands high pressure, high temperatures, copes well with increased mechanical stress. The coefficient of linear expansion is minimal. No fittings are required to connect the pipes and cannot be damaged by rodents. One meter costs 130 rubles.
Plastic pipes
Plastic pipe products on the market are represented by a small assortment, which is 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 are well tolerated by various loads, even chemical ones, but there is one drawback - the complicated way of joining. To do this, use couplings or cold welding (using a special adhesive).
When glued, the ends of the pipes are cut strictly perpendicular to the axis of the product, cleaned with sandpaper and degreased with acetone. Glue is applied and the two abutting ends are pressed against each other. In this position, you must hold the connection for at least 1 minute. After joining, the areas are cleaned of glue.
PVC pipes are 20 mm in the range of 190-200 rubles per 1 m.
Polyethylene
The products on the market are available in two versions: high and low pressure. The first ones with a diameter of 20 mm are not available. They have a low density and, accordingly, 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 conduct 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 supply systems. Hot water softens the polyethylene, which leads to ruptures, especially at the junctions of adjacent elements.
Technical characteristics of HDPE pipes with a diameter of 20 mm:
| Characteristic | Indicator |
| Wall thickness, mm | 2,0-2,3 |
| Maximum water pressure, MPa | 1,25-1,6 |
| Weight of 1 rm, kg | 0,12 |
Low modulus of elasticity creates conditions under which water hammer cannot occur. Low-pressure polyethylene has high frost resistance. Such pipes do not burst even in severe frost. Connection methods - welding or couplings. The second is more often used as the simplest and less costly.
The price for one meter of HDPE pipe with a diameter of 20 mm is 17 rubles.
XLPE
The most flexible pipe goes on sale in coils of 100 m. It is used not only for cold water supply. The material easily tolerates high temperatures, so the products are used for laying hot water supply and heating systems.
Specifications:
| Characteristics | Indicators |
| Outside diameter, mm | 20 |
| Internal, mm | 16 |
| Weight of 1 rm, kg | 0,122 |
| Liquid volume in 1 rm, l | 0,2 |
| Working pressure, MPa | 6-10 |
| Maximum allowable temperature, ° С | +95 |
| Minimum bending radius, mm | 100 |
| Service life, years | 50 |
The pipe sections are connected using press fittings or ferrules. Such a pipe costs on average - 75 rubles / r.m.
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.
On the market, polypropylene pipes are presented in two modifications:
- simple;
- reinforced.
A frame made of aluminum foil, aluminum mesh (braid), fiberglass or composite material, which includes polypropylene, fiberglass and fiberglass, is laid inside the reinforced products.
Simple pipes made of pure polymer have a specific marking - PN. Manufacturers offer brands that differ from each other in the working pressure of the flowing water. For cold water pipes, pipes of 20 mm PN10 brand are suitable, which can withstand a water pressure of 1.0 MPa. Manufacturers apply blue lines on their surfaces.
If a pipe is required for hot water supply or for a heating system, it is better to use PN20 or 25. These are marked with red stripes. Plastic pipes of this type are characterized by increased rigidity. You can bend them, but the bending radius is large. Therefore, during the installation process, fittings of various configurations and designs are used. Connection method - welding.
Specifications differ depending on the brand of the product. Service life depending on fluid temperature and pressure:
- PN10. If the water temperature does not exceed 20C, and the pressure is 1.3 MPa, such a pipe will last up to 10 years. Reducing the pressure to 1 MPa increases the service life up to 50 years.
- PN25. The service life increases from 10 to 50 years if at a temperature of + 20C the pressure drops from 3.4 to 3.2 MPa.
As the temperature rises, the service life decreases. The same goes for pressure.
The cost of a plastic pipe made of polypropylene for a water supply system with a diameter of 20 mm also depends on the brand of pipes. Average price for 1 running meter PN10 is 17 rubles, PN16 - 21 rubles. The same PN16, only reinforced, costs 55 rubles.
Reinforced-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 holds the foil and the outer polymer braid together;
- another layer of cross-linked polyethylene;
- between them is an adhesive composition.
It is a flexible product, which goes on sale in coils, the length of the material is 100 m. The outer diameter is 20 mm, the inner diameter is 16 mm, and the wall thickness is 2 mm. Other characteristics:
| 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 of 1 rm, kg | 0,143 |
| Volume 1 running meter, liter | 0,2 |
The price of a metal-plastic pipe is within 70 rubles / r.m. Usually they are installed in the system of "warm floors", rarely in the water supply, because other plastic pipes are cheaper.
