Pn 16 which means MPa. Industrial pipeline fittings: purpose and classification

Industrial pipeline fittings - the name of a number of devices intended for installation on units, vessels or pipelines. The main operational task of pipeline valves is the control (distribution, shutdown, discharge, regulation, etc.) of the flows of gaseous, powdery, liquid, gas-liquid working media by increasing or decreasing the flow area.

Traditionally allocate two main operating parameters pipeline fittings: nominal size (nominal passage) and nominal (nominal) pressure.

Nominal passage (DN or Du) - a parameter by which the connecting elements of the pipeline are characterized: the nominal passage (nominal size of the reinforcement) is expressed in millimeters and is approximately equal to the internal diameter area of ​​the connected element.

* It is allowed to use for hydraulic and pneumatic devices.
** Not allowed for general purpose fittings.

Nominal (conditional) pressure (PN or Ru) - the maximum overpressure in the system at a working medium temperature of 20 ° C, which allows to ensure the operational service life individual elements connecting fittings and pipeline. Designations and values ​​of nominal pressure must correspond to the ratings specified in GOST 26349-84.

The choice of nominal pressures less than 0.01 MPa is carried out from the R5 series, more than 100 MPa - from the R20 series (according to GOST 8032-84).

When marking pipeline fittings, the design of which was developed before 01/01/1992, it is allowed to use the designation of nominal pressure Ru. Nominal pressure designation PN6 can be used instead of designation PN 6.3.

Operating pressure Pр - maximum overpressure at operating temperatures that provide a given mode of operation of pipeline valves.

Trial pressure Ppr - excess pressure at which it is possible to carry out hydraulic tests of pipeline fittings and connecting elements for tightness and strength. Test pressure values ​​are determined according to GOST 356-80. If the value of the working pressure is below 20 MPa, then the test pressure will be approximately 1.5 times higher than Pp.

The classification of industrial pipeline fittings is carried out taking into account several technical, functional and operational characteristics.

Application area

Depending on the area and scope of application, the following types of industrial pipeline fittings are distinguished: general-purpose pipeline fittings, fittings for special conditions works, special fittings, transport and ship fittings, sanitary fittings.

1. General purpose pipe fittings is produced serially and is intended for operation in any spheres and branches of industry.
2. Pipe fittings for special working conditions designed for operation in power systems with high technological characteristics. In addition, industrial fittings of this type are used in the installation of pipelines, through which highly toxic and aggressive working media are transported.
3. Development and production special fittings carried out, as a rule, on special orders of individual departments or state enterprises. Scope of special fittings - ship power plants, objects of the Ministry of Defense, nuclear power plants, etc.
4. Transport and ship fittings produced for operation in the transport industry and, in particular, is used in shipbuilding. For fittings of this class, increased technical requirements: in the production of transport fittings, dimensions, weight of products, the possibility of operating fittings in various climatic zones and other characteristics are taken into account.
5. Plumbing fittings used to complete and organize functionality various kinds household equipment. Reinforcement of this type, as a rule, has a small diameter and does not cause any difficulties in operation. Production and release of sanitary fittings is carried out on production lines. In the production of sanitary fittings, special attention is traditionally paid to consumer characteristics and, in particular, product design.

Functional purpose

Depending on the functional purpose, the following types of industrial pipeline fittings are distinguished: shut-off, control, distributive-mixing, safety, protective and phase-separating.

1. Functional purpose stop valves- full opening or blocking of the flow in the pipeline. The operation of shut-off valves is determined by technological requirements.
2. Pipeline control valve used to control the parameters of working media by changing the flow rate. The control valve is various models pressure regulators, liquid level regulators, throttling fittings, control valves, etc.
3. main destination dividing and mixing fittings(valves, cocks) – mixing of the working medium flows, redirecting the flows in the required direction.
4. Safety fittings used for automatic protection of pipelines and equipment from overpressure. During the operation of safety fittings, emergency situations are prevented by dumping excess working medium from the system. The most common types of safety fittings are impulse safety devices, safety valves, bypass valves, diaphragm rupture devices.
5. Functional purpose protective fittings(shutoff and check valves) - automatic protection of pipelines and equipment from failures in the technological process due to changes in the parameters of working media, changes in the direction of flows. During the operation of protective fittings, emergency situations are prevented without the release of excess working medium from the system.
6. Phase separating pipeline fittings will be used if it is necessary to organize automatic separation of working environments, taking into account their current state and phase. The most common types of phase separation fittings are gas separators, steam traps, air separators and oil separators.

Construction types

Depending on the design features, the following types of industrial pipeline fittings are distinguished: gate valves, valves (gates), taps, gates.

1. gate valve- constructive type of pipeline fittings, the movement of the working body of which is perpendicular to the direction of the flow of the working medium. As a rule, gate valves are most often used as shut-off pipeline valves.
2. Valve (valve)- a constructive type of industrial valves, the movement of the regulating or shut-off body of which is carried out parallel to the axis of the flow of the working medium. There is a variety of this type of fittings - membrane valves. In the design of a membrane valve, a membrane acts as a shut-off element, which is fixed between the body and the cover along the outer perimeter and performs the function of sealing the shut-off body, body parts and moving elements relative to the external environment.
3. Tap- a constructive type of pipeline industrial fittings, the regulating or shut-off body of which has the shape of a body of revolution (or part of it), rotates around its axis and is located arbitrarily with respect to the direction of flow.
4. Gate- a constructive type of pipeline fittings, the regulating or shut-off body of which has the shape of a disk and rotates around a non-own axis.

Conditional pressure of the working medium

• Vacuum fittings (working medium pressure below 0.1 MPa abs.)
• Low pressure (0-1.5 MPa)
• Medium pressure valves (1.5-10 MPa)
• High pressure (10-80 MPa)
• Pipe fittings of ultrahigh pressure (80 and more MPa)

Method of connection to the pipeline

Depending on the method of fastening to the pipeline, the following types of industrial fittings are distinguished: coupling, nipple, fittings for welding, coupling, pin, flange, fitting.

1. Accession coupling industrial fittings to the pipeline is carried out using couplings having an internal thread.
2. Accession nipple fittings to the pipeline is made using a nipple.
3. Accession pipeline fittings intended for welding carried out by welding. This method of connecting fittings to the pipeline has both advantages and obvious disadvantages. In particular, high-quality welding of fittings guarantees absolute tightness of the connection, does not require maintenance (tightening of flange connections), however, it can cause certain problems during repair work, work on the replacement of reinforcement elements.
4. Fastening tie rod to the pipeline is made using nuts and studs.
5. .Connection flange fittings to the pipeline is made using flanges. This method fastening also has advantages (possibility of multiple installation and dismantling of fittings, high strength, the ability to operate under a wide range of operating pressures and passages) and disadvantages (possible weakening of the fastening, loss of tightness of the connection, large weight and dimensions).
6. Mounting pin fittings to the pipeline is made on an external thread with a collar for sealing.
7. Choke fittings attached to the pipeline with fittings.

Sealing method

Depending on the method of sealing, the following types of industrial pipeline fittings are distinguished: membrane, bellows, stuffing box.

1. With help membrane fittings the sealing of the housing elements, movable connecting elements relative to the external environment is carried out. In addition, membrane fittings allow sealing in the valve.
2. Gland fittings allows to ensure the sealing of the spindle or rod relative to the external environment: the sealing of the connection is carried out with the help of stuffing box packing, which is in direct contact with the movable spindle or rod.
3. Bellows fittings used to seal moving parts (spindle, rod) relative to the external environment. As a seal, a bellows is used, which is a power or sensitive element of the structure.

Control method

Depending on the control method, the following types of industrial pipeline valves are distinguished: actuated valves, valves with remote, automatic and remote control.

1. main feature fittings designed for remote control, - the absence of a governing body. The connection with the control body is made with the help of transitional elements (columns, rods, etc.).
2. Control actuated pipeline fittings by means of a drive (remotely or directly).
3. Control industrial pipeline fittings designed for automatic control, carried out without the participation of the operator. Automatic control is provided due to the direct impact of the working environment on the power or sensing element, or by means of signals coming to the drive from instruments and devices of the automatic control system.
4. Control manual valve performed by an operator.

According to GOST 9544-93, for all types of valves (with the exception of special valves and valves with an electric drive), the following classes of tightness of connections are established at a conditional pressure of 0.1 MPa or more.

Table of the minimum duration of hydraulic tests of the blockage:

Table of the dependence of the values ​​of media and pressures for hydraulic tests on nominal (conditional) pressures and diameters:

The choice of medium for hydraulic testing is carried out depending on the functional purpose of pipeline fittings and compliance with the requirements of GOST (water - GOST P 51232-98, air - class 0 GOST 17433-80). When conducting hydraulic tests, the temperature of the test medium must be less than 5 ° C, but not more than 40 ° C. Permissible error in measuring leaks: ± 0.01 cm³ / min. for leaks less than 0.1 cm³/min. and ±5% for leaks greater than 0.1 cm³/min.

Reinforcement symbol according to the classification of TsKBA (table-figure)

Classification of pipeline industrial fittings (classification of TsKBA) is made on the basis of accepted symbols, consisting of letters and numbers. The first two digits in the product marking indicate the type of industrial fittings (see Table 1). The letter (or combination of letters) after the first two digits indicates what material the body of the product is made of (see Table 2). Letters (or a combination of letters) are followed by one or two digits indicating the model number. If three digits are indicated after the letter designation, then the first one is the type of drive (see table 3), and the next two digits are the model number. The last letters in the marking indicate the material from which the sealing surfaces are made (see Table 4) or indicate the method by which the internal coating body of the product (see table. 5). Reinforcement made without welded or plug-in rings is designated "bk".

Table 1

table 2

Table 3

Table 4

Table 5

In parallel with the classification system of TsKBA, a system of codes obtained as a result of abbreviation of the factory name of products is often used to classify industrial fittings. For example, to designate a ball valve with a nominal pressure of 16 kg / cm³ and a nominal bore of 15 mm, the designation KSh-16/15 is used. To designate some types of reinforcing structures, only the number of the drawing documentation is used, according to which they were manufactured. Often, when classifying products, a letter indicating the name of the manufacturing plant is indicated.

To classify valves intended for operation in such industries as oil refining and oil production, a symbol of numbers and letters is also used. If the letters indicate the type of reinforcement, then the digital value indicates the operational parameters of the product. For example, a cast wedge gate valve of the 2nd modification, having a nominal pressure of 16 kg / cm³ and a nominal bore of 200 mm, is designated as ZKL2-200-16.

It is customary to use abbreviations to designate the working environment in catalogs of industrial pipeline fittings (see Table 6).

Table 6

Selection of valves for gas distribution systems

When choosing pipeline shut-off valves intended for operation in gas distribution systems, it is necessary to be guided by the following provisions and normative documents: PB 12-529-03, SNiP 42-01-2002 and SP 42-101-2003. In gas supply networks with pressure up to 1.6 MPa, it is recommended (depending on operating conditions) to use the types of pipeline fittings indicated in the table:

When installing pipeline fittings on external gas pipelines in areas with cold climatic conditions, it is necessary to use products in climatic design UHL1, UHL2, HL1, HL2. When conducting installation work pipe fittings on internal gas pipelines in heated premises, it is necessary to choose products in the climatic version U1, U2, U3, U5, UHL4, UHL5, HL5, and for unheated premises it is recommended to use UHL3, HL3 (according to GOST 15150-69).

When installing pipeline fittings on internal (in unheated premises) and external gas pipelines in areas with a moderately cold climate, it is necessary to choose products in the climatic version U1, U2, U3, UHL1, UHL2, UHL3 (according to GOST 15150-69).

Choose pipeline fittings for external and internal gas pipelines in unheated premises, taking into account the operating pressure in the system, climatic conditions, housing material, recommended based on the data given in the table:

Carbon steel

* Manufacture of body parts of fittings should be carried out from the following materials: stamped and forged products - wrought alloy grade D-16 (it is possible to use alloy D-1), cast products - guaranteed quality with mechanical properties not lower than grade AK - 7h (AL-9) (according to GOST 1583-93).

It is customary to choose the temperature of the coldest week with a probability of 0.92 (according to SNiP 23-01-99) as the design temperature for the operation of the fittings and the temperature of the working medium.

The hermetic density of the gate of taps and gate valves with a conditional (nominal) passage of up to 80 mm must correspond to class B. If there is a conditional passage of more than 80 mm - class C (according to GOST 9544-93).

The hermetic tightness of the gate of tension cone valves with a nominal pressure of up to 0.1 MPa, which are not subject to GOST 9544-93, must comply with the class standards for a working pressure of 0.1 MPa (according to GOST 9544-93).

The hermetic tightness of the gate of valves, which are installed on LPG liquid phase gas pipelines, must comply with class A. When installing valve congestion on other types of gas pipelines - compliance with class B (according to GOST 9544-93).

Pipeline industrial fittings involved in gas supply systems must have a passport in which it is recorded that the working medium for this product is liquefied or natural gas.

In some cases (subject to compliance with the requirements for the tightness of products; with the resistance of the sealing materials of the valve and body connectors to the transported gas), the operation of valves designed for natural or liquefied gas is possible for steam, water and ammonia.

The choice of working and conditional pressure of shut-off valves is carried out depending on the parameters of the working pressure in the system and must correspond to the data indicated in the following table:

According to the requirements of GOST 4666-75, all types of pipeline valves must be marked and have a distinctive color. The marking is applied to the body of the product and must contain the manufacturer's trademark, operating or nominal pressure, nominal bore and, if necessary, an indicator of the direction of the flow of the working medium. Coloring of a cover and the body of stop valves is carried out depending on material.

The electric drive of shut-off valves must be made in an explosion-proof design.

The main characteristic of the pipeline is the diameter and wall thickness of the pipes from which it is made. Each pipe has two diameters: inner D in and outer D n. Between the inner and outer diameters of the pipes there is the following relationship:
,
where S is the pipe wall thickness.

When the wall thickness of the pipe changes, the inner diameter of the pipe changes, while the outer diameter of the pipe remains constant, since its change inevitably causes a change in the dimensions of the attached fittings and fittings.

In order to preserve for all elements of the pipeline (pipes, fittings and fittings) the value of the flow area, which provides the design conditions for the passage of liquid, steam or gas, the concept conditional pass. The nominal diameter of pipes, fittings and fittings is understood as the average inner diameter of pipes (in the light), which corresponds to one or more outer diameters of pipes. The nominal bore is denoted by the letters DN with the addition of the nominal bore in millimeters: for example, a nominal bore with a diameter of 150 mm is indicated DN 150. The true inner diameter of pipes is usually not equal to and does not correspond (with rare exceptions) to the nominal diameter. So, for example, for pipes with an outer diameter of 159 mm with a wall thickness of 8 mm, the true inner diameter is 143 mm, and with a wall thickness of 5 mm - 149 mm, however, in both cases, the conditional bore is assumed to be 150 mm.

Nominal diameters of fittings, fittings, as well as all parts technological equipment devices to which pipes or fittings are attached are established by GOST 28338-89 “Pipeline connections and fittings. Conditional passages (nominal dimensions). Rows. These quantities have the following range of meanings:

The wall thickness of pipes and pipeline parts is selected depending on the highest pressure of the medium (gas or liquid) transported through the pipeline, on its temperature and on the mechanical properties of the pipe metal.

As is known, the mechanical strength of the metal of pipes, fittings and fittings changes with increasing temperature. To link the pressure and temperature of the medium flowing through the pipeline, the concept of "conditional pressure" was introduced, which is denoted by the letters P y.

According to GOST 356-80 “Conditional test and working pressures. Rows. Conditional pressure (P y) should be understood as the highest overpressure at a medium temperature of 293 K (20 ° C), at which the permissible long work fittings and parts of the pipeline, having specified dimensions, justified by the calculation of strength for the selected materials and their strength characteristics, corresponding to a temperature of 293 K (20 ° C).

Test pressure (P pr) should be understood as excess pressure at which a hydraulic test of fittings and pipeline parts for strength and density with water at a temperature of at least 278 K (5 ° C) and not more than 343 K (70 ° C) should be carried out, if the regulatory and technical documentation does not indicate the specific value of this temperature. The maximum deviation of the test pressure value should not exceed ±5%.

The working pressure (P p) should be understood as the highest overpressure at which the specified mode of operation of valves and pipeline parts is ensured.

The nominal pressure values ​​of fittings and pipeline parts must comply with next row: 0.10 (1.0); 0.16 (1.6); 0.25 (2.5); 0.40 (4.0); 0.63 (6.3); 1.00 (10); 1.60 (16); 2.50 (25); 4.00 (40); 6.30 (63); 10.00 (100); 12.50(125); 16.00 (160); 20.00 (200); 25.00 (250); 32.00 (320); 40.00 (400); 50.00 (500); 63.00 (630); 80.00 (800); 100.00 (1000); 160.00 (1600); 250.00 (2500) MPa (kgf / cm 2).

For fittings and pipeline parts, the production of which was mastered before the entry into force of GOST 356-80, conditional pressures of 0.6 (6) are allowed; 6.4 (64) and 8.0 (80) MPa (kgf / cm 2).

The production of hydraulic tests with test pressure is necessary to check the reliability of the pipeline under operating conditions, therefore, the test pressure is always 1.25-1.5 times greater than the working and conditional pressure, unless the regulatory documentation establishes even higher test pressure values.

Polypropylene (PP) is a thermoplastic high temperature polymer. It is obtained by polymerization from a mixture of propylene with the addition of metal complex catalysts and stabilizers. PP pipes belong to the group plastic pipes, which also includes products made of metal-plastic, PVC, HDPE and PEX.

In this article:

Main purpose

Due to the special properties of polypropylene, the scope of pipes made of this material is quite wide.

They are used in the installation of hot and cold water supply systems, for heating, sewerage and ventilation systems, underfloor heating, in technological lines of food and chemical industries, irrigation systems, etc.

In this case, the laying of pipes can be carried out open or in a closed way: inside walls under various finishing materials, in channels and mines; pipes can be laid directly underground - in general, there are a lot of installation options.

Advantages

Thermoplastic polymer products for pipelines have an impressive list of advantages.

These include:

• sufficient mechanical strength and resistance to sudden changes in pressure or temperature;
• high environmental friendliness of materials and aesthetic design;
• chemical resistance to aggressive environments and toxic substances;
• high dielectric properties that prevent the electrical conductivity of the material;
• good sound absorption (polypropylene muffles the vibrating and rumbling sounds that the coolant makes during the flow through the pipeline);
• high anti-corrosion properties and no deposits inside the pipes;
• the elastic properties of the material do not allow water to freeze, which ensures reliable operation and long service life of the heating system;
  the highest reliability of connections among other types of plastic pipes;
• a wide range of different types of connecting and shut-off valves, allowing you to mount pipeline systems of any configuration and complexity;
• convenience, simplicity and speed of installation;
• light weight, low cost of materials and connecting elements;
• unpretentiousness in service and durability of operation.

Flaws

Disadvantages relate to the features of the operation of the product:

Pipe bending with a gas burner

1. The low heat resistance of the material requires a very careful approach to the choice of PP pipes (it is necessary to take into account the heat resistance index or immediately look after it).
2. Polypropylene is difficult to deform, as a result of which it is impossible to change the direction of the pipe. You have to resort to the help of additional fittings (corners, tees, contours).
3. A rather high linear expansion when heated (especially for non-reinforced pipes) requires the use of special installation rules and special compensators.
4. For laying pipes, a special welding machine, which, due to the peculiarities of its design, is not always possible to use in a limited space or in a hard-to-reach place.
5. Polypropylene is exposed to direct sunlight - this causes premature aging of the material.

Types of PP pipes and decoding of markings

Manufacturers produce several types of polypropylene pipes, which differ in wall thickness and the presence of an additional reinforcing layer of aluminum foil or fiberglass.

Each type of product has standardized external and internal dimensions of various diameters, its purpose and appropriate marking.

Main specifications is the operating temperature of the coolant and the nominal internal pressure in the pipe. The service life of the pipeline directly depends on these parameters.

Marking includes:

• letters "PN" - designation of nominal pressure;
• the numbers "10, 16, 20, 25" - they correspond to the value of the nominal working pressure in atmospheres (kgf / sq.cm).

Classification of polypropylene pipes

Polypropylene pipes came into use relatively recently - in the 60s of the 20th century. Their wide area of ​​operation is explained by high strength, lightness, ease of installation, ease of installation of fittings.

Polypropylene pipes - scope

• transportation of chemically active liquids. Polypropylene is a completely inert material;
• pressurized gas supply. Polypropylene withstands pressure up to 25 atmospheres. For the same reason, it is used for pneumatic technology;
• as irrigation, spray water supply;
• in water supply of hot and cold liquid;

What is polypropylene

It is an organic synthetic polymer - thermoplastic and non-polar. In 1957 given material began to polymerize using a Ziegler-Natta catalyst, and set up its industrial production.

Although the material is plastic under the influence of high temperatures, in its normal state it has high strength, is chemically inactive, practically does not absorb moisture, and does not transmit electricity. It is suitable for the distillation of food liquids.

The main advantages of polypropylene pipes:

1. practically do not corrode;
2. excellent resistance to mechanical and bioactive influences;
3. practically do not create noise and vibration;
4. fittings are installed easily and in any part of this material;
5. almost absolute safety for human life and health;
6. heat resistance and low heat loss during transmission hot water;
7. durability of operation, which several times exceeds the service life of pipes made of steel alloy;
8. ease.

Polypropylene pipes marking

1. Single layer. Brands:

- PPH. Made from homopropylene. Are used in the industry, for arrangement of ventilation and transfer of cold water;

- PPB. Made from block copolymer. They are used for laying pipelines that have to withstand strong pressure and external forces - floor heating, water supply under strong pressure;

– PPR. Made from random copolymer. The main feature is the uniform distribution of the load. Used in underfloor heating and plumbing. Sun protection (UV rays) required if used outdoors;

– PPS. They are fire resistant. Operating temperature - no higher than 95 degrees. Used in fire hazardous conditions.

2. Multilayer. They have increased strength and a reduced coefficient of thermal expansion when compared with their single-layer counterparts. They can be reinforced with aluminum foil and, accordingly, smooth or perforated. Fiberglass reinforcement is also possible. Brands:

– PN10. The number in the marking after the letters means the maximum working pressure. Operating temperature - 45 degrees;

– PN16. Operating temperature - 60 degrees. Used for arranging cold water supply with high pressure;

– PN20. Operating temperature - 95 degrees. Used for installation of heating systems, including centralized ones;

– PN25. Operating temperature - 95 degrees. Used for mounting heating systems, floor heating and hot water supply.

Polypropylene pipes have firmly entered the plumbing system. Plumbing is the primary communication system with which the improvement of any housing begins, whether it is an apartment or a country house. After all, neither sewerage, nor heating, nor water intake household appliances will be able to function without water.

Today, domestic manufacturers produce a wide range of pipeline products, which differ both in terms of technical parameters and cost. Knowing what classification is and which polypropylene pipes for heating can be used in a residential area becomes an indispensable tool for a modern designer.

Polypropylene pipes for heating and water supply differ from steel counterparts affordable price, light weight, high resistance to corrosion and external influences, therefore they are widely used for domestic and industrial water supply. Every year, the number of households that associate the heating of their home with piping with polypropylene pipes is growing.

Polypropylene pipes, classification and marking

Polymeric products are produced and labeled based on operating conditions:

• PN 10- are produced for cold water supply with a liquid temperature of not more than + 20˚С;
• PN 16- also designed for cold water, but with high pressure;
• PN 20- universal pipes for hot (up to + 80˚С) and cold water supply;
• PN 25- are made with fiberglass reinforcement, aluminum or an additional layer of polymer. They are characterized by high tensile strength and minimal coefficient of thermal expansion. This brand is bought when polypropylene pipes for heating are needed.

The marking of polymer pipes also includes other letter designations that indicate the presence of plasticizers and additives that determine the technical characteristics and properties of polypropylene:

• PPH- polypropylene homopolymer. Designed for cold water supply and ventilation systems because it is not able to withstand high temperatures;
• RRW- block copolymer of polypropylene with a polyethylene content of up to 30%. Possesses considerable flexibility, resistance to low and high temperatures;
• PPR- static (random) copolymer of polypropylene with a crystalline molecular structure. He is not afraid of water hammer, high temperatures and pressure in the line. In addition to plumbing, they are used in the installation of water heating and underfloor heating;
• PPs- fire-resistant and high-strength type of polypropylene with flame retardant. It differs from other types of polymers by its high maximum allowable temperature (95˚С).

Polypropylene pipes for water supply - advantages

Manufacturers of polypropylene pipes give a guarantee on their products for more than 50 years, since this material has become widely used in industrial scale since 1960, while many pipelines are still in stable operation.

Due to the unique production technology, polypropylene pipes have a high threshold of heat resistance and strength, withstanding pressure in the line up to 10-20 atmospheres.

Polypropylene pipes for water supply are not afraid of exposure to aggressive reagents and significant temperature changes, even when freezing and thawing, they do not lose their integrity.

- simple installation that does not require special skills and profile specialization. For the installation of water supply, you will need additional components (fittings, shut-off and control valves), as well as special equipment for heating and welding polypropylene.

We suggest you familiarize yourself with how best to choose polypropylene pipes for plumbing. Understand which is better, which pipe is intended for what. Watch video review.

Polypropylene pipes for a reliable water supply system

Traditional steel pipes are almost never installed in modern residential buildings. They were replaced by more reliable technologies using polypropylene pipes, which provide high tightness in hot and cold water supply systems.

Polypropylene pipes are easy to install, do not rust, withstand high water pressure and hydraulic shocks, are lightweight and affordable.

For the manufacture of polypropylene pipes, an environmentally friendly type of plastic is used, in which there are no decomposing components. Pipes are classified depending on the scope of products for cold water, hot water and drinking water.

There are a lot of similar products on the market that differ in diameter, thickness of plastic, the presence or absence of a reinforced layer. To select suitable pipes for each specific case, it is necessary to consult with specialists.

Advantages of polypropylene tubular products:

- absence harmful substances;
– deposits do not appear inside;
– are not subject to corrosion;
- the connections are tight;
- no need for coloring;
– ease of installation;
- low cost;
– can be used for drinking water supply;
– service life exceeds 50 years;
- resistance to mechanical stress;
– good flexibility;
- light weight.

The disadvantage of plastic pipes made of polypropylene is that they elongate significantly as a result of thermal expansion of the material. To solve this problem, manufacturers suggest using reinforced pipes in hot water systems.

Fiberglass or aluminum foil is used as a reinforcing layer. Fiberglass several times reduces the temperature elongation, so that the pipes retain their dimensions when heated strongly.

In cold water supply systems, there is no need to use reinforced pipes. In this case, simple polypropylene products can be installed, which gives significant savings and facilitates the installation process.

The difference between fiberglass reinforced pipes and aluminum interlayer pipes is that the former are more convenient to install. When pipes with an aluminum reinforcing layer are mounted, the foil makes the cutting process difficult. When cutting pipes, it is necessary to obtain a neat butt end, and due to the presence of foil, this is much more difficult to do.

Installation of polypropylene pipes

When installing polypropylene pipes, traditional metal welding is not used, so sparks do not fly in the room, which increases the safety of work. Pipe connections are made using a special device that melts the plastic at the very end of the pipe, allowing you to create a monolithic and completely tight interface. In this case, you can do without rubber gaskets and all kinds of seals.

Polypropylene pipes are significantly superior to steel products in terms of ease of installation, system reliability, as well as decorative and operational performance. Unlike steel pipes, plastic pipes are not prone to vibrations. Solid particles do not stick to their inner surface, which eliminates the problem of diameter reduction and reduction in throughput.

Polypropylene pipes are equally well suited for creating durable and hermetic water systems in apartment buildings, country houses and cottages.

The economic benefit from their use is that they are affordable, do not require much effort during transportation, are very quickly and easily installed, and serve for many decades without requiring expensive repairs. Thanks to quality installation such pipes, the probability of flooding your home and neighbors' apartment is much lower than when using ordinary metal pipes.

Polypropylene (PP - according to Russian, PP - according to international classification) pipes are tougher metal-plastic pipes, they are assembled by diffusion welding using fittings: angles, tees, etc. Polypropylene pipelines use permanent connections, the pipeline is assembled on welded fittings once and for all. Unlike a metal-plastic pipe, which, in fact, is a thin aluminum pipe coated inside and out protective layer plastic, polypropylene pipe - completely plastic. The plastic used to make pipes also differs. Unlike polypropylene pipes, most metal-plastic pipes use polyethylene.

Due to the special properties of materials, the polypropylene pipeline system can be used in: water supply of houses; connection of boilers; water distribution; plumbing risers; distribution by floors (normal or at each sampling point with individual connection); connecting the pipeline to existing water supply networks, assembled from metal pipes; heating networks; connection to the boiler plant; distribution devices; heating risers; connection of metal radiators.

The long service life of the serial pipe made of polypropylene allows it to be used for all known types of pipeline laying: open laying, wall laying, concealed laying. For internal systems hot water supply and heating, the most heat-resistant type of polypropylene is used - a random copolymer (marked as PP type 3 or PP Typ 3). Pipelines made of this material, depending on the operating pressure, can serve for a long time with a liquid temperature of up to 95°C. The estimated duration of the use of the pipeline is more than 50 years, and in pipelines of cold water supply even more - from 50 to 100 years. Temperatures of the order of 100°C due to short-term failures do not adversely affect the service life of the pipeline.

All parts of the pipeline that are in contact with drinking water, comply with the current standards of Russia. Suitability of polypropylene for work in contact with liquid food products are confirmed by national certificates of Belgium, Germany, Great Britain, Italy, Spain, USA.

Pipes (fig. 20) are divided into three categories:

• PN 10 - thin-walled version, for cold water supply (up to +20°C) and underfloor heating (up to +45°C), nominal working pressure 1 MPa (10.2 kg/cm²);
• PN 20 - universal pipe, used for hot water supply (temperature up to +80°C), nominal pressure 2 MPa (20.4 kg/cm²);
• PN 25 - reinforced with aluminum foil, for hot water supply and central heating (up to +95°C), nominal pressure 2.5 MPa (25.49 kg/cm²).

Polypropylene pipe PN 16 - for cold and hot water supply (up to + 60 ° C), nominal working pressure 1.6 MPa (16.32 kg / cm²), could be the fourth in the list of categories of these pipes, but it is rare.

Rice. 20. Polypropylene pipes

	PN 10 Size, mm	D, mm	S, mm	d, mm
	20x1.9	20	1,9	16,2
	25×2.3	25	2,3	20,4
	32×3.0	32	3	26,0
	40×3.7	40	3,7	32,6
	50×4.6	50	4,6	40,8
	63×5.8	63	5,8	51,4
	75×6.9	75	6,9	61,2
	90×8.2	90	8,2	73,6
	110×10	110	10	90,0
	PN 20 Size, mm	D, mm	S, mm	d, mm
	16×2.7	16	16	10,6
	20×3.4	20	3,4	13,2
	25×4.2	25	4,2	16,6
	32×5.4	32	5,4	21,2
	40×6.7	40	6,7	26,6
	50×8.4	50	8,4	33,2
	63×10.5	63	10,5	42,0
	75×12.5	75	12,5	50,0
	90×15.0	90	15	60,0
	110x18.4	110	18,4	73,2

Unlike metal-plastic pipes, the aluminum layer in PN 25 pipes is closer to the outside and, most often, perforation is made on it, which makes it possible not to use glue to fasten the pipe layers. The connection of the outer and inner layers of polypropylene with each other or with an aluminum layer occurs through perforated holes, which, in turn, can be through or surface for various manufacturers. The direct connection of polypropylene with aluminum significantly increases the stability and strength of the pipes. Pipes PN 25 are intended for special use - mainly in heating pipelines, as well as in pipelines for hot water supply, but can also be used for cold water supply systems. For example, among domestic plumbers, this is one of the most “favorite” pipes, it is installed on all types of wiring.

Polypropylene pipes are gray, white, black and green. A color other than black does not mean any restrictions on the use of pipes. The black color of the pipe shows that it is the most protected from ultraviolet radiation.

It should also be noted that the service life of polypropylene pipes declared by the manufacturer is 50 years, which implies that the pipeline will be operated at normal pressure and normal temperature. That is, pipes can withstand significant long-term pressures, but the temperature of the transported liquid must be low, or, conversely, the temperature of the liquid can be very high, but the pressure must be low. At high pressure and high temperature the service life of the pipe is sharply reduced and can reach up to 1–5 years. To determine the service life of pipes operating in extreme conditions, there is a special table. We will not give it, since at the household level such long-term loads do not occur in domestic pipelines, and the pipe will withstand short-term emergency situations associated with a sharp pressure jump or a sharp jump in the temperature of the transported liquid.

For polypropylene pipelines, all types of fittings necessary for the installation of engineering communications are produced, which makes it possible to refuse to include metal parts in the pipe system and to perform optimal installation of the pipeline. And also allow you to connect a polypropylene pipeline to a metal one. Pipes are environmentally friendly and are successfully used in pipelines of cold and hot water supply and heating. Thanks to fittings with chrome and brass inserts, pipes can be easily combined with existing steel fittings and plumbing fixtures.

Coupling with inner