Plastic pipes have already conquered the consumer market due to their characteristics and low cost. The assortment continues to grow, because manufacturers are constantly developing new product modifications, which are now not much inferior to steel and cast iron pipes. Each type of polymer material has its own characteristics, so first you need to figure out what this or that plastic is suitable for, and then select the dimensions and calculate the number of pipes.
Scope of plastic pipes for water supply
Polymer pipes are used not only for arranging a water supply system - external or internal. They are used to transport gases and chemically aggressive substances. Plastic is a neutral substance. It does not react with acids or alkalis. The products are used for laying sewage systems, since the inner surface of the pipes does not contribute to the reproduction of pathogenic bacteria - microorganisms cannot form colonies.
Depending on the technical characteristics, polymeric materials are used in hot and cold water supply systems. You just need to choose the right pipes so that the operating temperature range matches the capabilities of the plastic.
There are especially strong polymers that operate in very low temperatures. They are suitable for the construction of an autonomous water supply and sewerage system in the Far North, where the level of soil freezing is about 2.5 m. It is important to take this indicator into account, since there is always a certain amount of water in the soil. Turning into ice, such a liquid is capable of deforming the line if it does not have a safety margin, so the pipes are laid either to a great depth, or other materials are selected.
Plastic pipes are used for casing wells of any depth, even artesian ones, the depth of which is about 300 m. For summer residents and greenhouse owners, polymers are a cheap solution for organizing irrigation in the summer. It is known that plastic does not withstand direct sunlight and quickly loses its quality, but its cost is not high enough to worry about replacement.
To replace and strengthen old steel water pipes, the method of internal insertion of a plastic pipe is used after preliminary cleaning of the old one. Thus, the liquid begins to flow over the new plastic and the water becomes cleaner.
Advantages and disadvantages
Polymer pipes are the most demanded for the following parameters:
- do not react to moisture, unlike steel products, corrosion does not damage the inner walls, and they can remain intact and clean for a long time;
- the material is not toxic, drinking water does not lose its taste;
- plastic has low thermal conductivity, it maintains the temperature of the transported liquid, which is important for heating systems;
- noise is lower than that of metal pipes;
- you can choose a modification that will tolerate temperature changes well, but such products are more expensive due to various additives;
- plastic pipes are easy to install - they are connected with fittings, couplings, welding;
- the weight of the products compares favorably with heavy cast-iron, ceramic and steel structures, therefore, for laying plastic, you do not need to attract special equipment and pay for its rent.
The disadvantages of polymeric materials appear when they are incorrectly selected or poorly mounted. This mainly happens when the work is done by non-professionals.
Types of pipes and their characteristics, requirements according to GOST
Pipes are distinguished by material:
- polyethylene - plain or sewn;
- polypropylene;
- metal-plastic;
- PVC or UPVC.
Pipes from low pressure polyethylene most often used in cold water supply systems, for example, to transport water to a house from a well or well. The operating temperature of polyethylene is from 0 to 40 degrees, the pipes can withstand a pressure of 25 atmospheres. There are raw materials from which "technical" pipes are made - usually it is secondary production waste. For drinking water, there are separate requirements from which material to make pipes. If the line is planned to be installed on the surface of the soil, soot is added to the polyethylene - it protects the plastic from ultraviolet rays. Such products are black. HDPE combines the durability of cast iron and the strength of steel, but at a lower cost. In theory, the material can serve for about 300 years. The manufacturer claims a guaranteed service life of 50 years.
Polypropylene pipes more resistant to hot water and can withstand up to 85 degrees for a long time. In a cold water supply system, polypropylene will last about 50 years, in a hot one - up to 25 years. Given the peculiarities of the domestic centralized heating system, in which short-term emissions of boiling water with a temperature of about 100 degrees can occur, polypropylene is a good solution for an apartment. In a private house, the temperature is regulated by a sensor in the boiler, so it is unlikely that the material will be damaged. Like all other plastic pipes, polypropylene is non-corrosive and chemically neutral. Poorly conducts heat and sound waves, capable of working in pressure systems. The material bends poorly, therefore, various additional elements are used to turn the line - tees, bends, corners. Czech polypropylene is considered more expensive, it is white and slightly stronger. Turkish manufacturers save on aluminum and do not adhere to the same thickness of plastic in all areas, their pipes are cheaper.
Metal-plastic Is a multi-layer material. Plastic - cross-linked polyethylene, inside which aluminum or copper foil is sewn. Two layers of adhesive provide a strong bond between the polymer and the foil. Cross-linked polyethylene has high quality characteristics, one of which is the preservation of the geometric shape when heated. Reinforced-plastic pipes bend well, which allows you to save on connecting elements. When using them, complex expensive tools are not needed, which makes it easier for beginners and non-professionals to install the water supply system.
Unplasticized polyvinyl chloride - material that is used in pressure and non-pressure water supply and sewerage systems. These pipes can be used to transport both chemically aggressive substances and food products in liquid form. PVC is completely safe. The walls of the pipes are three-layer - this allows you to reduce the weight of the product and its thickness, without sacrificing strength. The elements are connected using a socket, where a rubber O-ring is inserted. To make the connection strong, the joints are cleaned of dirt and grease, since these substances damage the rubber seals over time.
Criterias of choice
Selection criteria should be based not only on the quality of the material, but also on other indicators, for example, the cost of installation work. When connecting large-diameter plastic pipes, making one joint can be much more expensive than the entire pipe. For example, when connecting HDPE pipes with a diameter of 1 m, the cost of the joint will cost about 1000 rubles at a price of 1 kg of pipe about 80 rubles.
The second criterion is the operating temperatures of the system for which the plastic is selected. For cold water - one material, for hot water supply or heating system - another. According to sales statistics, polypropylene and metal-plastic are most often chosen for hot water, since they have the best indicators of thermal expansion and elongation.
The third parameter is the size of the pipes, namely the diameter. Depending on the number of water consumption points and the number of people living in a private house, pipes of a larger or smaller diameter are installed.
You can choose products from a domestic or foreign manufacturer. High-quality Russian pipes are not much cheaper than imported ones.
Dimensions and markings
The sizes of plastic pipes for water supply are very diverse. The thickness of the walls, the inner and outer diameters, and the length of the pipe section may differ. It should be borne in mind that only products with the same wall thickness and the same size can be connected by welding.
Marking is needed in order to distinguish the characteristics of plastic pipes by material of manufacture and technical parameters.
For houses and apartments, pipes with a diameter of 50 and 110 mm are most often used. If the house is large and a large amount of water is consumed per day, the diameter of the inlet pipe should be larger.
Installation features
Installation of plastic pipes is carried out in several ways. Some are more suitable for closed systems that will later be hidden in concrete or walls. Others are designed for open use.
There are 4 ways to connect plastic products:
- soldering;
- compression fittings;
- press fittings;
- trumpet.
For installation, additional parts may be required - clamps, adapters for changing the diameter, crosses, elbows, tees.
The soldering method is used to assemble PVC and polypropylene pipes. To ensure that the products do not deform with temperature changes, they perform the "loop" technique, due to which there is no stress at the joints. This is especially true for polypropylene solid lines, the length of which exceeds 3 meters.
When soldering, the main thing is not to overheat the joints, otherwise the connection will be performed poorly and will quickly depressurize. Within 4 seconds, the heated joints must be connected and fixed, otherwise the material will cool down and do not join at the molecular level.
For the installation of an external water supply or sewage system, it is recommended to plan the wiring diagram so that it has fewer bends and turns. In such areas, blockages most often occur or water reduces the flow rate, which is fraught with the formation of an ice plug.
To protect plastic from low temperatures, they are wrapped with mineral wool with aluminum foil or electrically heated. These works must be performed at the stage of laying pipes in the ground.
The cost of plastic pipes
The cost of plastic products is formed from many indicators - the amount of consumable material and its quality, the distance over which the pipes are delivered. The type of material also matters. For example, the price of PVC pipes for hot water supply will be higher than polyethylene pipes with a lower operating temperature range.
Products of an imported manufacturer, especially of well-known brands, are always higher than the similar quality of pipes of a little-known domestic manufacturer. It is recommended to consult with the manager before buying - you may not have to overpay for the brand.
Due to the popularity of plastic pipes in construction, there are many low-quality products made from recycled materials on the market that are unsuitable for drinking water mains. It is necessary to buy materials for construction at proven points of sale.