Sewer pipes made of unplasticized polyvinyl chloride, created using the latest technology, have high technical characteristics, which affects the durability of underground utilities. High-quality PVC-U plastic has become the main raw material for the production of tubular elements and fittings, since they work best in specific operating conditions, where the use of soft plastic is limited.
Characteristics of PVC-U pipes
Raw materials were obtained in Germany for the replacement of metal products. Solid polyvinyl chloride works efficiently and for a long time under certain conditions. Elements from the new material have a long service life and chemical inertness. Their price optimally matches the characteristics of plastic.
PVC plastic is used for the manufacture of pens, cards, cable windings. It is obtained from recycled materials (up to 40%), petroleum products and salt. NPVH incorporates unmodified food resins in primary processing so that the material does not lose its physical and mechanical properties: strength, hardness and ductility, otherwise the pipes will break, crumble and bend, which will not allow them to be used, for example, for casing wells. Plasticizers are removed from the composition of the components, which gives the elements the necessary stiffness, strength and eliminates chemical reactions in contact with liquids.
Solid polyvinyl chloride has a special cross-shaped structure of molecules, which is obtained after heating and subsequent cooling.
The unique properties of the material make it possible to produce pipes for widespread use, which determines their size, thickness and stiffness class.
Appointment
They are used for sewer wiring inside the building and external networks, as well as for pressure sewer. For each type, products with special characteristics are intended, therefore their interchange is not recommended, since the use of parts with high strength inside the house unreasonably increases the cost of the project. The use of lightweight thin-walled pipes for an external network will not ensure its reliability and durability.
From pressure head sewer pipes NPVH, sewer sections are mounted after fecal pumps. They have no sockets, so the joints are welded. Products withstand not only high external pressure from the ground, but also internal created by a hydraulic machine.
The size
Non-pressure PVC-U pipes for internal sewerage have a cross-sectional diameter in the range of 25-50 mm. According to the rules of SNiP, they are intended for a system for discharging drains from showers, bathtubs, washbasins, kitchen and washing machines. For toilets, a section of 110 mm is used, for risers and collectors from 110 mm to 150 mm. External lines are mounted from pipes d110 and higher.
For economical use, the manufacturer produces elements of different lengths. Indoors, it is most convenient to mount wiring from sections ranging from 30 cm to 2 m, for external networks from 50 cm to 6 m. The proposed assortment allows you to reduce the number of connections and increase their tightness.
Labeling of plastic pipes, in contrast to metal products, is performed on the outer diameter.
Wall thickness
Difficult operating conditions require varying degrees of strength. Depending on demand, PVC parts are available in one or three layers. The latter modification has high wear resistance, as the outer layers are used for PVC-U, and foamed polyvinyl chloride is used as the inner layer, which is resistant to temperature extremes, chemical and mechanical influences, durable and can withstand various processing methods.
For wiring inside the building, thin-walled sewer pipes with a thickness of not more than 3.5 mm are used. They do not experience pressure from the soil, like external sewage pipelines, the thickness of which can vary from 3.5 mm to 15 mm.The use of three-layer pipes made of unplasticized PVC increases thermal insulation and strength, reduces the weight of the structure.
Hardness class
NPVC products are classified by types of ring stiffness, which determines their ability to withstand pressure loads from the outside and from the inside. The marking SN2 or 2 kN / m2 indicates the average strength class L, therefore, the elements are used for house wiring. These are light pipes, they are also used when laying in pedestrian zones, under children's and sports grounds.
Products with characteristic N, normal stiffness SN4, are laid in the ground to a depth of 6 m, they withstand small dynamic loads from rarely passing vehicles.
Strength class SN8 shows high ring stiffness, thick-walled pipes can be laid 80 cm from the ground or to a depth of more than 6 m, and they are laid at 8 m mark under highways.
Selection recommendations
For internal and external sewage, products that meet the following requirements are used:
- temperature range from 0 degrees to 45 degrees;
- the ability to withstand from the inside the pressure of the medium, which is created by the pump to move liquids and gases;
- resistance to many types of chemical and organic compounds: butter, milk, mercury, acids.
The smooth inner surface of the PVC-U material reduces the risk of clogging. Products are aesthetic and safe. For wiring inside buildings, gray pipes are used, for outdoor installation - red.
Mounting Features
According to the method of attachment, the elements of NPVH are performed with or without a bell. For the installation of the latter, welding is used. With the help of extensions at the ends of parts, fittings of various configurations, couplings and turns, sewer wiring is collected. Adhesive technology can increase the tightness of joints.
Installation with sockets is considered the easiest. To prevent leaks, rubber pads are used. Cold welding is used for pressure pipes, it is carried out using chemical compositions. Adapter couplings reliably connect products made from heterogeneous raw materials.
Advantages and disadvantages of PVC-U pipes
Increasingly, users give preference to modern materials with undeniable advantages over cast iron and ceramic elements:
- Lightweight, do not cause problems during transportation or installation.
- Do not rust.
- Resistant to abrasion and chemicals, which allows the use of products for wastewater with mechanical pollution.
- Amenable to any processing and easy to cut.
- They have a long service life with proper operation (50 years).
Minuses:
- Limitations on the temperature range, from -5 to 40 degrees, can withstand +60 degrees for a short time.
- Not protected from rodents.
- Low fire resistance, toxic substances are released during combustion.
Low frost resistance makes the products brittle. To prevent freezing of the pipeline, it is packaged in heat-insulating materials.
