Advantages and applications of pipes made of unplasticized polyvinyl chloride (UPVC)

Pressure sewerage is a wastewater disposal system where the movement of the medium occurs not under the influence of gravity (gravity), but due to the operation of the pump. Pressure networks have a number of advantages, which include reducing the length of the pipeline, the possibility of increasing the slope, and minimal risk of blockages. They are used to service private residential buildings, administrative facilities with local water supply, industrial complexes, and in agriculture (livestock farming, poultry farming).

It is obvious that when the pump is operating, the sewer pressure pipe experiences excess pressure, which must be effectively counteracted by the pipeline wall. No expansion, stable throughput and geometry are the main requirements when choosing systems for organizing sewerage. PVC pipes for pressure sewerage meet these requirements; they are leaders in the construction of modern pressure networks.

What is uPVC

UPVC (in the international designation system PVC-U) is one of the three basic types of polyvinyl chloride. Its chemical formula is (C2H3Cl)n. In parentheses is the composition of a single polymer unit; the symbol n indicates an infinite number of repetitions during the polymerization of the material. In addition to uPVC, the basic types of polyvinyl chloride include chlorinated polymer (CPVC, or PVC-C) and a fairly large group of modified materials with special properties (PVC-M).

The answer to the question of how PVC differs from uPVC lies in the performance characteristics of these materials, which determine their scope of application. More information about this can be found in the regulatory documents regulating the production of different types of products. In relation to pipes, these are the following GOSTs:

• GOST 32413-2013 – free-flow pipes made of PVC-U for external drainage networks;
• GOST 32412-2013 – the same for internal sewerage networks;
• GOST R 51613-2000 – products made of PVC-U for pressure networks for supplying cold technical and drinking water;
• GOST R 52134-2003 – pressure pipes made of polymer materials for water supply and heating, including PVC-U and PVC-C.

The division of pipes into areas of application ensures their optimal use from a technical and financial point of view. This means that, depending on the intended purpose, you do not need to use products with clearly redundant characteristics to solve your problems.

How to calculate the casing diameter size

Before purchasing materials and constructing a water well, its size should be determined. Manufacturers offer a wide range of casing materials for wells.

The minimum diameter of products is 90 mm, the maximum is 225 mm. Wall thickness varies from 7 to 20 mm. For a domestic well, a common size is casing pipes 125 mm in diameter. Thick-walled products are used for installing deep artesian wells.

When choosing the size of a well, one should be guided by considerations of practicality. The dependence here is this: the more water is required daily, the more power the pump will use. When calculating the diameter of a well, the depth of its drilling also matters; the larger it is, the more powerful the pump will be required to lift it to the surface.

The more powerful the pump for pumping water, the larger its dimensions and the wider the well required to immerse it. Pumps with a flow of up to 8 mm have a casing diameter of up to 122 mm, which does not require a pipe larger than 125 mm.

Decoding the abbreviation

The abbreviation UPVC means “unplasticized polyvinyl chloride,” that is, a pure material of the homopolymer class. We have already given its chemical formula. To impart new properties, various additives are introduced into the material, with the help of which the following qualities are improved:

• thermal resistance;
• mechanical strength;
• resistance to aggressive environments;
• plastic;
• frost resistance, etc.

The listed characteristics, or rather their meanings, provide answers to the question of what is the difference between PVC and uPVC. Note that PVC-C polymer has wider ranges of values ​​for most operational parameters compared to PVC-U. This applies to thermal resistance, mechanical strength and a number of other indicators.

How are products labeled?

Each building element must be marked with a special sign, which is applied to the outer surface of the pipe. The marking consists of combinations of letters and numbers in which the characteristics of the product are encoded.

Knowing the meanings of each sign, you can determine several important product parameters:

• Name;
• outer diameter (minimum);
• bell type.

The marking shows the thickness of the wall and indicates its purpose. Using the symbols you can also determine the date of manufacture and GOST number.

All of the above parameters are basic for labeling. If necessary, the manufacturer also provides additional information that every consumer should know. Symbols are applied to the surface of the pipe with a very heated tool. It is important to carry out this operation with extreme caution so as not to degrade the performance of the product. The distance between signs must be maintained within one meter.

PVC and uPVC pipes: what is the difference

Consumers are most often interested in the differences between PVC and uPVC pipes from a practical point of view in order to choose the most suitable materials to solve their problems. However, among questions of this kind there are also those that relate to other aspects. For many, the differences between PVC and UPVC pipes are important in such parameters as:

1. Material . Its properties are of decisive importance for the range of pipes in terms of diameter, wall thickness, methods of their installation, as well as for the operational characteristics of pipelines assembled from them.
2. Life time . From this point of view, products made from PVC-U and PVC-C are equivalent. Their service life is at least 50 years, which is confirmed by existing cases of operation of utility networks from such pipes. Laboratory tests indicate that pipelines made from PVC and uPVC products can last up to 100 years.
3. Difference in areas of application . In this case, use the instructions of regulatory documents (GOSTs) that regulate this issue. Restrictions on the use of pipes are determined by their operational properties, which are established for products of different sizes and methods of their installation.
4. Characteristics of use . The fundamental difference between PVC and uPVC pipes is the temperature of the working environment for which they are designed. For uPVC products, the upper temperature limit of transported liquids in continuous operation is 45 °C. For PVC-C pipes, this indicator is 95 °C.
5. Connection method . Pipes made of any grade of polyvinyl chloride are connected into a socket and couplings with O-rings or using glue. PVC, unlike polyethylene, is not welded.
6. Appearance and color . In appearance, PVC and uPVC are colorless materials of varying degrees of transparency, and they are indistinguishable from each other. The color of the finished product is used for its visual identification and is achieved by introducing appropriate pigments into the materials. Gray color is recommended for internal sewer pipes, orange-brown tones for external sewer pipes, and dark gray for pressure pipes.
7. Frost resistance . This indicator for PVC pipes is not critical, since they are not intended for open installation. However, uPVC is more resistant to low temperatures . PVC-C “freezes” earlier and becomes more brittle.
8. Flammability . Polyvinyl chloride has a high combustion temperature, which can only be reached in a severe fire. Non-flammable grades of PVC are used in the production of electrical products, for which such temperatures can be reached without open flame. Taking into account the purpose of PVC pipes, they have no restrictions on their use in terms of fire safety requirements.

For uPVC products, the upper temperature limit of transported liquids in continuous operation is 45 °C. For PVC-C pipes, this indicator is 95 °C.

Types of pipes for well construction

Drilling a well is only part of the problem that must be solved in order to provide your summer cottage or garden plot with water coming from underground sources. To raise water to the surface, you need a pump, and first you need to lower a casing pipe into a hole drilled in the ground.

Construction of a well with casing pipe

As mentioned above, products made from metal, asbestos cement and PVC (UPVC) can be used. For use as casing metal and asbestos-cement pipes, lifting equipment is required, since they are heavy. In addition, rolled metal pipes are quite expensive, so their use is associated with significant financial costs.

Asbestos-cement products are more affordable, but they are inconvenient to install and are very susceptible to mechanical loads. When using asbestos-cement pipes as casing, situations often arise when they burst under the influence of external loads, which leads to erosion of the well and its subsequent clogging. Restoring it in this case is almost impossible, so the solution is new drilling. This naturally leads to additional financial costs.

Socket connection of uPVC pipes

PVC-U pipe: GOST and marking features

The rules for labeling any product are established by the relevant regulatory documents. For example, the marking of non-pressure PVC-U pipes according to GOST 32413-2013 contains the following information in the following order:

• product material;
• outer diameter and pipe wall thickness in mm - for example, 250x4.9;
• indicator of the ratio of the diameter and wall thickness of the SDR product as an integer;
• ring stiffness indicator SN in kN/m2, indicating the permissible load when laying underground pipes;
• link to the regulatory document according to which the product is manufactured.

According to GOST R 51613-2000, the following product labeling is established:

• product material;
• SDR indicator;
• outer diameter and wall thickness of the pipe in mm;
• purpose - drinking or technical;
• link to the regulatory document.

For products in accordance with GOST R 52134-2003, a similar designation scheme is used, but after the third item of the list, the service class and nominal operating pressure of the pipes are added to the marking.

Tips on how to choose

The choice of pipes primarily depends on the purpose and operating conditions: for pressure or non-pressure systems, at depth or laying in basements, ducts, buildings.

Electrical, telephone or Internet networks are laid in pipes or corrugated pipes; often the communications are not sealed.

The second important factor is the working pressure in the water supply or soil pressure on free-flow networks. The choice of pipe design (smooth-walled, corrugated, double-layer corrugated, bell-shaped) depends on these factors. In addition, the temperature regime is taken into account - overheating of the ground in summer, freezing in winter.

The choice of ring stiffness class for a PVC-U sewer pipeline depends on the density and thickness of the soil layer above the communication. If the depth is greater or the sewerage system is located under a road or parking lot, strong corrugated pipes with a two-layer wall are used. Corrugation is also used for water pipes with high pressure or with a very massive screed over a heated floor system.

Estimated cost

The cost of the most common types of uPVC pipes in private construction - socket elements Ø 110 mm - is 110 rubles per meter pipe, 315 rubles for a three-meter pipe. Pressure bell-shaped round products with PN 1.6, 6 m long, cost from 1,750 rubles. A corrugated pipe for sewerage Ø 110 mm with SN6 costs from 170 rubles per meter.

Cost of uPVC communications

The cost of uPVC communications is low. Only thermistor fittings and collapsible couplings are relatively expensive. But when installing non-pressure sewer networks, they are rarely needed. When installing water pipes of small diameters for a private house, they are also not necessary; the usual bell-shaped structures are used.

Advantages of uPVC pipes

The growing popularity of uPVC and PVC pipes is due to such advantages of their use as:

• reliability;
• durability;
• ease of installation;
• a sharp reduction in operating costs for pipeline maintenance;
• pipes are completely harmless to humans and the environment.

Nowadays, polymer pipes are widely used in the modernization of utility networks and in new construction. They replace pipes made of steel, cast iron and other materials.

Main sizes

Specific pipe sizes are available for each system. This makes it possible to easily select the desired type of product and its diameter:

• internal systems – 25-110 mm;
• instrument wiring – 110-150 mm:
• installation of risers – 110-150 mm;
• external drainage – 110-1000 mm.

When installing a fairly powerful structure, the diameter of the product can be more than 1000 mm.

Each system uses pipes of different lengths:

• internal – 300-2000 mm;
• external – 500-6000 mm.

It should be noted that the length of the socket is also added to 6 m.

The marking always indicates the outer diameter, which must be taken into account when selecting the required set of cylindrical products for creating a sewer system.

PVC-U sewer pipes

Here we will answer the question of how PVC sewer pipes differ from uPVC sewer pipes. First of all, let us point out the incorrectness of the question. For the production of sewer pipes, only PVC-U is used. Other types of polyvinyl chloride have clearly redundant characteristics for this. If you can afford not to count money, then the sewer can be assembled from pressure pipes in accordance with GOST R 52134-2003. Moreover, a significant part of the range of pipes made of uPVC and PVC according to different GOST standards coincides in standard sizes.

Installation features

Depending on the method of connection, uPVC elements are made with or without a socket. For 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 assembled. Adhesive technologies make it possible to increase the tightness of joints.

Installation using sockets is considered the simplest. Rubber gaskets are used to prevent leaks. Cold welding is used for pressure pipes; it is performed using chemical compounds. Adapter couplings reliably connect products made from dissimilar raw materials.

Purpose

Purpose of PVC-U sewerage systems:

• the products are used in the internal drainage system;
• during the construction of main communications;
• when draining household liquids;
• for rainwater;
• for drainage.

According to their purpose and area of ​​application, plastic pipes are:

• having a bell and without bell;
• operating under pressure and non-pressure.

Bell-shaped structures are produced for gravity networks. In this case, the tightness of the joints is created by a rubber cuff, which is located inside the socket. And socketless structures are installed on pressure communications. They are fixed using adhesive joints, or fittings, which allow you to create bends, forks and turns.

Strength classes

When choosing a product, it is important to know what loads the sewer line can withstand under soil pressure and traffic. Based on this indicator, uPVC pipes are divided into ring stiffness class. It is denoted by the abbreviation SN and powers of 2. It is measured in kilonewtons per m2:

• SN2 – rigidity up to 2 kN/m2 (the main can be laid to a depth not exceeding 1 meter). Lightweight products are laid under the sidewalk, green area and in places where traffic loads are not expected.
• SN4 – up to 4 kN/m2 (placement depth up to 6 m). Medium-type products are chosen for installation in places where traffic is not so high.
• SN8 – up to 8 kN/m2 (placement depth up to 8 m). Heavy-duty products are chosen for installation in industrial areas and places with heavy traffic flow.

Corrugated bends, for example, belong to class SN8.

PVC-U pressure products are further subdivided according to the amount of internal pressure they can withstand. It is important to keep in mind that PN is not a pressure value, but rather a strength class for this parameter.

Advantages and disadvantages

Now let’s look at the advantages and disadvantages of the products; this information is necessary for everyone who is going to purchase and use these pipes in household work.

uPVC pipes have many advantages:

• can be operated under large temperature differences;
• have a smooth inner surface;
• resistant to chemically active substances;
• have high strength;
• withstand heavy mechanical loads;
• have a long shelf life;
• made from environmentally friendly materials;
• They are light in weight, which makes them easy to transport and stack;
• have a low price.

But it is worth taking into account the disadvantages of PVC-U sewer pipes. The downside is that the temperature of the liquid being transported should be no more than +45ºC. Sometimes a short increase in temperature to +80ºC is acceptable. Violation of the temperature regime can shorten the service life of products.

Wall thickness

Products made of polyvinyl chloride installed in internal drainage systems are thin-walled products. Typically, the thickness of the side of the pipe is in the range of 3.2-3.5 mm.

When laying external sewerage, the minimum thickness of the product is 3.2 mm. When large diameter pipes are installed, this parameter can reach 15 mm. For special conditions, it is possible to install a product with a three-layer wall.

For an internal sewerage system, a pipe made of a homogeneous material with a certain wall thickness is suitable. For external drainage, it is customary to use three-layer pipes, for the manufacture of which special foam material is used. As a result, the strength remains unchanged, while the weight of the product is greatly reduced. The type of wall and its thickness determines the ring stiffness - the ability of the product to resist compressive loads.

Taking this indicator into account, each pipe is divided into several classes:

• SN2;
• SN4;
• SN8.

The higher the number, the higher the strength of the product.

SN2 is mainly used in low pressure areas. SN4 is laid in a trench 0.8-6 m deep, taking into account the weight of the soil and the absence of dynamic pressure. SN8 class products are placed at a depth of more than 6 m.

Performance characteristics

The material allows you to create products with high performance characteristics:

• Smooth external and internal surface, which gives pipe products greater throughput.
• Complete absence of corrosion phenomena.
• Wide range of operating temperatures - from -50 to 78 degrees.
• Excellent strength and rigidity to withstand pressures up to 25 bar.
• Light weight.

The bottlenecks of uPVC products are:

• Restrictions on use at sub-zero and high temperatures (at -50 the material begins to break down, at +90 it loses its qualities). For this reason, they are not used in heating systems.
• Instability when interacting with nitrobenzene, acetone, dichloroethane.