Polypropylene (PP - according to Russian, PP - according to international classification) pipes are stiffer than metal-plastic pipes, they are assembled by diffusion welding using fittings: angles, tees, etc. forever and ever. Unlike a metal-plastic pipe, which is, in fact, a thin aluminum pipe covered inside and out with a protective layer of plastic, a polypropylene pipe is completely plastic. The plastic used to make pipes also differs. Unlike polypropylene pipes, polyethylene is used in most metal-plastic pipes.
Due to the special properties of the materials, the polypropylene pipeline system can be used in: water supply of houses; connection of boilers; distribution of water; plumbing risers; distribution by floors (usual or at each point of selection with individual connection); connecting the pipeline to the existing water supply networks, assembled from metal pipes; heating networks; connection to the boiler plant; switchgears; heating risers; joining metal radiators.
The long service life of a serial polypropylene pipe allows it to be used for all known types of pipelines: open laying, wall laying, hidden laying. For internal systems of hot water supply and heating, the most heat-resistant type of polypropylene is used - 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 cold water pipelines it is even longer - from 50 to 100 years. Temperatures of the order of 100 ° C, arising from short-term malfunctions, do not adversely affect the service life of the pipeline.
All parts of the pipeline in contact with drinking water comply with the current Russian standards. The suitability of polypropylene for work in contact with liquid food products is confirmed by the national certificates of Belgium, Germany, Great Britain, Italy, Spain, and the USA.
Pipes (fig. 20) are divided into three categories:
- PN 10 - thin-walled version, for cold water supply (up to + 20 ° С) and warm floors (up to + 45 ° С), nominal working pressure 1 MPa (10.2 kg / cm²);
- PN 20 - universal pipe, used for hot water supply (temperature up to + 80 ° С), 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 ° С), nominal working pressure of 1.6 MPa (16.32 kg / cm²), could become 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 |
|---|---|---|---|---|
| 20 × 1.9 | 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 | |
| 110 × 18.4 | 110 | 18,4 | 73,2 |
| D, mm | D 1, mm | D 2, mm | S, mm | |
|---|---|---|---|---|
| 20 | 13,2 | 21,2 | 4,0 | |
| 25 | 16,6 | 26,2 | 4,8 | |
| 32 | 21,2 | 33,2 | 6,0 | |
| 40 | 26,6 | 41,4 | 7,4 | |
| 50 | 33,2 | 52,5 | 9,1 | |
| 63 | 42,0 | 65,9 | 11,3 | |
| 75 | 50,0 | 77,9 | 13,3 |
Unlike metal-plastic pipes, the aluminum interlayer in PN 25 pipes is closer to the outer side and, most often, perforations are made on it, which makes it possible not to use glue to fasten the pipe layers. The connection of the outer and inner polypropylene layers 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 PP to aluminum greatly improves the stability and strength of the pipes. PN 25 pipes are intended for special use - mainly in heating pipelines, as well as in hot water supply pipelines, but they 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 available in gray, white, black and green. A color other than black does not imply any restrictions on the use of pipes. The black color of the pipe indicates 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 long-term significant 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 go up to 1–5 years. To determine the service life of pipes operating in extreme conditions, there is a special table. We will not cite it, since at the household level such long-term loads do not arise in domestic pipelines, and the pipe will withstand short-term emergencies associated with a sharp pressure jump or a sharp jump in the temperature of the transported liquid.
For polypropylene pipelines, all types of fittings are produced that are necessary for the installation of utilities, which allows you to refuse the inclusion of metal parts in the pipe system and to make an optimal installation of the pipeline. And also allow you to connect a polypropylene pipeline to a metal one. The pipes are environmentally friendly and are successfully used in pipelines for cold and hot water supply and heating. Fittings with chrome and brass inserts allow the pipes to be easily combined with existing steel fittings and plumbing fixtures.
 Coupling with inner |
Polypropylene pipes came into use relatively recently - in the 60s of the 20th century. Their wide area of operation is due to their 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;
- gas supply under pressure. Polypropylene can withstand pressures up to 25 atmospheres. For the same reason, it is used for pneumatic technology;
- as irrigation, spray water supply;
- in the water supply of hot and cold liquids;
What is polypropylene
It is an organic synthetic polymer - thermoplastic and non-polar. In 1957, this material was polymerized using a Ziegler-Natta catalyst, and its industrial production was launched.
Although the material is plastic under the influence of high temperatures, it has high strength in its normal state, is chemically inactive, practically does not absorb moisture, and does not allow electricity to pass through. It is suitable for the distillation of food liquids.
The main advantages of polypropylene pipes:
- practically do not corrode;
- excellent resistance to mechanical and bioactive influences;
- practically do not create noise and vibration;
- fittings are installed easily and into any part of a given material;
- almost absolute safety for human life and health;
- heat resistance and low heat loss when transferring hot water;
- durability of operation, which is several times longer than the service life of steel alloy pipes;
- ease.
Polypropylene pipes marking
1. Single layer. Brand:
- PPH. Manufactured from homopropylene. Used in industry for ventilation and cold water transmission;
- 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 even distribution of the load. They are used in underfloor heating and water supply installations. Protection from the sun (UV rays) is required if used outdoors;
- PPS... They are resistant to ignition. Working temperature - no higher than 95 degrees. Used in fire hazardous conditions.
2. Multilayer. They have increased strength and 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. Brand:
- PN10... The number in the marking after the letters indicates the maximum working pressure. Working temperature - 45 degrees;
- PN16. Working temperature - 60 degrees. Used for arranging cold water supply with high pressure;
- PN20... Working temperature - 95 degrees. Used for the installation of heating systems, including centralized;
- PN25. Working temperature - 95 degrees. They are used for installation of heating systems, underfloor heating and hot water supply.
Polypropylene pipes have become part of the water supply system. Plumbing is the primary communication system, which begins the improvement of any home, be it an apartment or a country house. Indeed, without water, neither sewerage, nor heating, nor water intake household appliances can function.
Today, domestic manufacturers produce a wide range of pipeline products, which differ in both technical parameters and cost. Knowledge of what classification is and which polypropylene pipes for heating can be used in a residential area is becoming an indispensable tool for a modern designer.
Polypropylene pipes for heating and water supply differ from their steel counterparts in their affordable price, low 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 who connect the heating of their home with strapping with polypropylene pipes is growing.
Polypropylene pipes, classification and marking
Polymer products are produced and labeled based on the operating conditions:
- PN 10- manufactured for cold water supply with a liquid temperature not exceeding + 20˚С;
- PN 16- also designed for cold water, but with increased pressure;
- PN 20- universal pipes for hot (up to + 80˚C) and cold water supply;
- PN 25- manufactured with fiberglass, aluminum or an additional layer of polymer reinforcement. They are characterized by high tensile strength and minimal coefficient of thermal expansion. This brand is bought when polypropylene pipes are needed for heating.
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:
- RRN- polypropylene homopolymer. Designed for cold water supply and ventilation systems, as it is not able to withstand high temperatures;
- RRV- block copolymer of polypropylene with a polyethylene content of up to 30%. Possesses considerable flexibility, resistance to low and high temperatures;
- PPR- static (random) polypropylene copolymer 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 retardant and high strength type of polypropylene with flame retardant. It differs from other types of polymers by a high indicator of the maximum permissible temperature (95˚С).
Polypropylene pipes for water supply - advantages
Manufacturers of polypropylene pipes give a guarantee for their products for more than 50 years, since this material has been widely used on an industrial scale since 1960, while many pipelines are still in stable operation.
Thanks to the unique production technology, polypropylene pipes have a high threshold of heat resistance and strength, withstanding pressure in the pipeline up to 10-20 atmospheres.
Polypropylene pipes for water supply are not afraid of the effects of aggressive reagents and significant temperature changes, even when they freeze and thaw, they do not lose their integrity.
- simple installation that does not require special skills and profile specialization. For the installation of the 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 that you familiarize yourself with how best to choose polypropylene pipes for water supply. Understand which is better, which pipe is intended for what. We watch the video review.
Polypropylene pipes for a reliable water supply system
Traditional steel pipes are hardly ever installed in modern residential buildings. They were replaced by more reliable technologies using polypropylene pipes, which ensure high tightness in hot and cold water supply systems.
Polypropylene pipes are easy to install, do not rust, withstand high water pressure and water hammer, are lightweight and affordable.
For the manufacture of polypropylene pipes, an environmentally friendly type of plastic is used, in which there are no decomposable components. Pipes are classified according to their application for products intended for cold water, hot water and drinking water.
There are many similar products on the market that differ in diameter, plastic thickness, and the presence or absence of a reinforced layer. In order to select the right pipes for each specific case, you need to consult with specialists.
The advantages of polypropylene pipe products:
- lack of harmful substances;
- deposits do not appear inside;
- not subject to corrosion;
- the connections are hermetically sealed;
- no need for staining;
- ease of installation;
- low cost;
- can be used to supply drinking water;
- service life exceeds 50 years;
- resistance to mechanical stress;
- good flexibility;
- low weight.
The disadvantage of polypropylene plastic pipes is that they elongate significantly as a result of the thermal expansion of the material. To solve this problem, manufacturers suggest using reinforced pipes in hot water supply systems.
Fiberglass or aluminum foil is used as a reinforcing layer. Fiberglass reduces the temperature elongation by several times, due to which the pipes retain their dimensions under strong heating.
In cold water supply systems, there is no need to use reinforced pipes. In this case, you can install simple polypropylene products, which gives significant savings and makes the installation process easier.
The difference between fiberglass-reinforced pipes and aluminum-lined pipes is that the former are more convenient to install. When pipes with an aluminum reinforcement layer are installed, the foil makes the cutting process difficult. When cutting pipes, you need to get a neat end, and due to the presence of foil, this is much more difficult.
Installation of polypropylene pipes
When installing polypropylene pipes, traditional metal welding is not used, so sparks do not fly out 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 sealed interface. In this case, you can do without rubber gaskets and all kinds of seals.
Polypropylene pipes significantly surpass steel products in terms of ease of installation, reliability of systems, as well as decorative and operational indicators. Unlike steel pipes, plastic pipes are not prone to vibration. Solids do not adhere to their inner surface, which eliminates the problem of reducing the diameter and reducing the throughput.
Polypropylene pipes are equally well suited for creating durable and sealed water supply systems in apartment buildings, country houses and cottages.
The economic benefit from their use is that they have an affordable cost, do not require much effort during transportation, are very quick and easy to install, serve for many decades without requiring expensive repairs. Thanks to the high-quality installation of such pipes, the likelihood of flooding your home and the apartment of your neighbors is much lower than when using ordinary metal pipes.
The main characteristic of a pipeline is the diameter and wall thickness of the pipes from which it is made. Each pipe has two diameters: inner D vn and outer D n. There is the following relationship between the inner and outer diameters of the pipes:
,
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 connected 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 was introduced conditional pass... Under the conditional passage of pipes, fittings and fittings is meant the average internal diameter of the pipes (in the light), which corresponds to one or more external diameters of the pipes. Nominal bore is designated by letters DN with the addition of the nominal size in millimeters: for example, nominal bore with a diameter of 150 mm means DN 150... The true internal diameter of pipes is usually not equal 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 nominal bore is taken equal to 150 mm.
The nominal sizes of fittings, fittings, as well as all parts of technological equipment of devices to which pipes or fittings are connected are established by GOST 28338-89 “Pipeline connections and fittings. Conditional passages (nominal sizes). Rows ". These values have the following range of meanings:
* Allowed to be used only for hydraulic and pneumatic devices
** For general purpose fittings it is not allowed to use
The thickness of the wall of pipes and pipeline parts is chosen depending on the highest pressure of the medium (gas or liquid) transported through the pipeline, on its temperature and the mechanical properties of the pipe metal.
As you know, the mechanical strength of the metal of pipes, fittings and fittings changes with increasing temperature. To correlate the pressure and temperature of the medium flowing through the pipeline, the concept of "conditional pressure" has been introduced, which is denoted by the letters P у.
According to GOST 356-80 “Test and working pressures. Rows ". The conditional pressure (P y) should be understood as the greatest overpressure at an ambient temperature of 293 K (20 ° C), at which the long-term operation of valves and pipeline parts with specified dimensions justified by strength calculations for the selected materials and their strength characteristics corresponding to temperature 293 K (20 ° C).
Test pressure (P pr) should be understood as the 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 normative and technical documentation does not indicate a specific value for this temperature. The maximum deviation of the test pressure value should not exceed ± 5%.
Working pressure (P p) should be understood as the highest excess pressure at which a given operating mode of valves and pipeline parts is ensured.
Values of nominal pressures of fittings and pipeline parts must correspond to the following series: 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 introduction of GOST 356-80, nominal 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 operation under operating conditions, therefore, the test pressure is always 1.25-1.5 times higher than the working and nominal pressure, if the regulatory documentation does not establish even higher test pressure values.
What are DN, DN and PN? Plumbers and engineers need to know these parameters!
DN - Standard indicating the nominal inside diameter.
PN - Standard indicating nominal pressure.
What is Doo?
Doo- formed from two words: Diameter and Conditional. DN = DN. Do is the same as DN. Simply DN is the more international standard. Du is a Russian-language representation of DN. Now it is absolutely necessary to abandon such a name Du.
What is DN?
DN- Standardized diameter representation. GOST 28338-89 and GOST R 52720
Nominal diameter DN(nominal diameter; nominal bore; nominal size; nominal diameter; nominal bore): A parameter used for piping systems as a characteristic of the connected parts of the valve.
Note - The nominal diameter is approximately equal to the inner diameter of the connected pipeline, expressed in millimeters and the corresponding nearest value from a series of numbers adopted in the prescribed manner.
How is DN usually measured?
According to the terms of the standard, it seems that it does not have a strict reference to the unit of measurement (written in the documents). But it means exactly the size of the diameter. And the diameter is measured by the length. And because the unit of measure for length can be different. For example, inch, foot, meter, and the like. For Russian documents, we simply measure in mm by default. Although the documents say that it is still measured in mm. GOST 28338-89. But it does not have a unit of measurement:
How does it not, if it does? Can you write in the comments how to understand this phrase?
It seems to have come ... DN (serial number of the diameter expressed in millimeters). That is, it does not have a unit of measurement, but, as it were, contains constant values (digital discrete values such as: 15,20,25,32 ...). But it cannot be designated, for example, as DN 24. Because the number 24 is not in GOST 28338-89. There are strict values in order as: 15,20,25,32 ... And only they need to be selected for designation.
DN is measured by the nominal diameter in mm (millimeter = 0.001 m). And if you see DN15 in Russian documents, then this will mean an inner diameter of about 15 mm.
Conditional pass- indicates that this is the inner diameter of the pipe, expressed in millimeters - conditionally. The term "Conditional" means that the value of the diameter is not accurate. We conventionally assume that it is approximately equal to some of the values of the standard.
The nominal bore (nominal size) is understood as a parameter used for piping systems as a characteristic of the connected parts, for example, pipe connections, fittings and valves. Nominal bore (nominal size) is approximately equal to the inner diameter of the connected pipeline, expressed in millimeters.
According to the standard from: GOST 28338-89 it is customary to choose the numbers that have been agreed upon. And you shouldn't come up with your own numbers with commas. For example DN 14.9 would be a designation error.
Nominal diameter approximately equal to the inner diameter of the pipeline to be connected, expressed in millimeters and the corresponding nearest value from a series of numbers adopted in the prescribed manner.
These numbers are:
For example, if the real inner diameter is 13 mm, then we write as: DN 12. If the inner diameter is 14 mm. then we take the value of DN 15. That is, we select the nearest number from the list of the standard: GOST 28338-89.
If in projects it is necessary to designate both the diameter and the thickness of the pipe wall, then it must be indicated as follows: ф20х2.2 where the outer diameter is 20 mm. And the inner diameter is equal to the difference in wall thickness. In this case, the inner diameter is 15.6mm. GOST 21.206–2012
Alas, we have to obey other people's standards
Any materials imported from abroad were most often developed using a different length dimension: Inch
Therefore, most often the dimensions are oriented to the Inch. Usually they write a quotation mark for the place of the word inch.
1 inch = 25.4 mm. Which is the same 1 ”= 25.4 mm.
Dimension table. Usually they write a quotation mark for the place of the word inch.
1/2 "= 25.4 / 2 = 12.7. But in reality this 1/2 “size is equal to a 15 mm pass. More precisely, it could be 14.9mm. for steel pipe. In general, dimensions may vary by a few mm. Therefore, in such cases, for accurate calculations, it is necessary to find out the inner diameter of a particular model separately.
For example, size 3/4 "= 25.4 x 3/4 = 19 mm. But we write in the documents “conditionally” DN20 - approximately the inner diameter is 20mm.
These are the actual sizes that most often correspond to the Russian translation.
The table shows the inner diameter in mm.
Nominal pressure PN: More details in GOST 26349 and GOST R 52720.
Has a unit of measurement: kgf / cm2. The designation kgf means kg x s (kilogram multiplied by s). c = 1. c characterizes, as it were, the coefficient of force. That is, by multiplying the kilogram (mass) by the force, we convert the mass to the force. This is such a correction for meticulous physicists. If you designate kg / cm2, in principle, you will not be mistaken either if you assume that we perceive mass as force. Also, such a unit as kg / cm2 is erroneous in that the pressure is formed from two units (force and area). Mass is another parameter. Because the mass only on the surface of the earth creates the force that presses on the earth (gravity). Value c = 1 at the surface of the earth. And if you fly away to another planet, then the force of gravity will be different, and the mass will create a different force. And on another planet, the coefficient c = 1 will be equal to another value. For example, c = 0.5 will create half the pressure.
What is PN for?
The PN value is needed in order to indicate to the device the pressure limit that cannot be exceeded for the normal operation of the device for which this value is set. That is, when designing, the designer must know in advance what maximum pressure the device is designed for.
For example, if the device was given a PN15 value, this means that the device is designed for operation with a pressure not exceeding 15 kgf / cm2. Which is approximately equal to 15 Bars.
1 kgf / cm2 = 0.98 Bar. Roughly speaking, the PN value is roughly equal to Bar or the atmosphere.
For example, if the device was given a PN10 value, then it is designed for a pressure not exceeding 10 bar.
Determination of PN according to the standard
The greatest excess working pressure at a working medium temperature of 293 K (20 ° C), at which a given service life (resource) of valve body parts having certain dimensions, justified by strength calculations for the selected materials and their strength characteristics at a temperature of 293 K (20 ° C).
Russian norms: GOST 26349-84, GOST 356-80, GOST R 54432-2011
European standards: DIN EN 1092-1-2008
American standards: ANSI / ASME B16.5-2009, ANSI / ASME B16.47-2006
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A series of video tutorials on a private house
Part 1. Where to drill a well?
Part 2. Arrangement of water wells
Part 3. Laying the pipeline from the well to the house
Part 4. Automatic water supply
Water supply
Private house water supply. Principle of operation. Connection diagram
Self-priming surface pumps. Principle of operation. Connection diagram
Calculation of a self-priming pump
Calculation of diameters from central water supply
Water supply pumping station
How to choose a pump for a well?
Pressure switch setting
Pressure switch wiring diagram
The principle of operation of the accumulator
Sewerage slope for 1 meter SNIP
Heating schemes
Hydraulic calculation of a two-pipe heating system
Hydraulic calculation of a two-pipe associated heating system Tichelman loop
Hydraulic calculation of a one-pipe heating system
Hydraulic calculation of the radial distribution of the heating system
Scheme with a heat pump and a solid fuel boiler - the logic of work
Valtec three-way valve + thermal head with remote sensor
Why does the heating radiator in an apartment building do not heat well?
How to connect a boiler to a boiler? Connection options and diagrams
DHW recirculation. Principle of operation and calculation
You do not correctly calculate the hydraulic arrow and collectors
Manual hydraulic calculation of heating
Calculation of a warm water floor and mixing units
Three-way valve with servo drive for DHW
Calculations of hot water supply, BKN. We find the volume, power of the snake, warm-up time, etc.
Water supply and heating constructor
Bernoulli equation
Calculation of water supply for apartment buildings
Automation
How servos and 3-way valves work
Three-way valve for redirecting the flow of the heating medium
Heating
Calculation of the thermal power of heating radiators
Radiator section
Overgrowth and deposits in pipes impair the performance of the water supply and heating systems
New pumps work differently ...
Infiltration calculation
Calculation of the temperature in an unheated room
Calculation of the floor on the ground
Calculation of the heat accumulator
Calculation of a heat accumulator for a solid fuel boiler
Calculation of the heat accumulator for the accumulation of thermal energy
Heat regulators
Room thermostat - how it works
Mixing unit
What is a mixing unit?
Types of mixing units for heating
System characteristics and parameters
Local hydraulic resistance. What is CCM?
Throughput Kvs. What it is?
Boiling water under pressure - what will happen?
What is hysteresis in temperatures and pressures?
What is infiltration?
What are DN, DN and PN? Plumbers and engineers need to know these parameters!
Hydraulic meanings, concepts and calculation of heating circuits
Nominal pressure- the nominal value of the technical parameter of various equipment, pumps, heat exchangers, pressure vessels, pipelines, fittings, etc. Any product has specific dimensions, justified strength calculations... The calculations take into account the materials selected for the manufacture with the characteristics of their strength at 20 ° C of the working environment, which ensures the specified service life of the equipment at a certain working pressure of the environment. This pressure is called nominal (conditional) pressure.
For many technical devices, this parameter is the most important due to the fact that it determines the strength characteristics of the equipment, the possibility of its interfacing with the connecting parts of various pipelines, the possibility of standardizing the requirements for testing the strength and density of materials and joints.
Standards and regulations
The definitions of this parameter, as well as its specific values, establish various state rules and standards approved in a particular country. In Russia, it is also known in technical documentation, literature, catalogs as conditional pressure, which is explained by the fact that this term was renamed in 1986 in connection with the release of new GOSTs to bring the designation to international standards. Initially, the new standards retained the designation Py as an alternative to the new designation PN(the notation is also used Rnom), these designations were used for marking technical products. However, since January 1, 2011, this alternative in the standards regarding the use of the obsolete designation ( Py) was deleted [ source not specified 85 days]. Thus, the only correct designation for the nominal pressure is currently PN.
Examples of established standards and regulations
Nominal pressure(in the hydraulic drive, pneumatic drive and lubrication systems) - the highest overpressure at which the device must operate during the specified resource (service life) while maintaining the parameters within the established norms.
Nominal pressure(in water supply and sewerage systems) is a constant internal overpressure of water that pipes and fittings can withstand during their entire service life (50 years) at a water temperature of 20 ° C.
Concept nominal pressure used in accordance with GOST 26349-84 for fittings and pipe fittings, such as flanges, bends, tees, etc., the same standard establishes specific values of the nominal (conditional) pressures used in this area.
Row nominal pressures in the hydraulic drive, pneumatic drive and lubrication systems, GOST 12445-80 is established.
In the "Rules for the Design and Safe Operation of Pressure Vessels (PB 03-576-03)", the following terms are defined:
- Test pressure - the pressure at which the vessel is tested.
- Working pressure - the maximum internal overpressure or external pressure that occurs during the normal course of the working process.
- Design pressure - the pressure for which the strength calculation is performed.
- Nominal pressure - design pressure at a temperature of 20 ° C, used when calculating the strength of standard vessels (assemblies, parts, fittings).
Range of nominal pressures
When designing a hydraulic drive, the nominal pressure in the hydraulic system is assigned in accordance with the normal range of pressures in accordance with GOST 6540-68 and GOST 12445-80 (MPa): 0.63; 1.0; 1.6; 2.5; 6.3; ten; 16; twenty; 25; 32. For pipeline valves (ball valves, wedge and gate valves) and pipeline parts (tees, couplings, transitions, elbows, bends, etc.) are assigned in accordance with the normal range of pressures in accordance with GOST 356-80 (MPa): 0 ,1; 0.16; 0.25; 0.4; 0.63; 1.0; 1.6; 2.5; 4.0; 10.0; 12.5; 16.0; 20.0; 25.0; 32.0; 40.0; 50.0; 63.0; 80.0; 100.0; 160.0; 250.0.
Polypropylene pipes: technical characteristics, application
What are polypropylene pipes? What are the scope of their application, technical characteristics, what does their marking mean? In this article we will try to understand all these issues. And to understand why this type of pipe structures is truly considered a unique material, without which today it is impossible to imagine the installation or repair of water supply, heating or sewer communications.
Polypropylene pipe - what is it?
Polypropylene is a type of thermoplastic polymer. It is made by combining (polymerizing) molecules of an ethylene gas derivative. International designation for polypropylene "PP". Next, we will consider in more detail polypropylene pipes: technical characteristics, properties and manufacturing technology of this new generation material.
Having a unique resistance to the effects of alkaline solvents and corrosive substances on it, the material is widely used in the installation of heating systems, water supply systems and sanitary facilities. It can withstand low temperature conditions (up to -10 degrees) or high (up to +110 degrees).
Basic properties of polypropylene pipes and their GOST
Modern polypropylene pipes, the technical characteristics and properties of which can be found in the table, are reliable, durable and quite affordable. The main and indisputable advantage is the fact that they are not subject to corrosive processes, resistant to temperature conditions, easy to install, made of environmentally friendly materials. The main properties according to GOST are presented below.
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GOST |
Parameter |
Index |
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Thermal conductivity, at + 200C |
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Density |
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Heat capacity at + 200C (specific) |
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Melting |
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Tensile strength (at break) |
34 ÷ 35 N / mm2 |
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| 18599 |
Elongation of the yield point |
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Yield strength (tensile) |
24 ÷ 25 N / mm2 |
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Expansion ratio |
A kind of polypropylene pipe. Scope of application
The latest technologies for the production of plastic products are polypropylene pipes. Specifications are presented below. 
- PN10 is a thin pipe. The service life is approximately 50 years. It is used when installing cold water supply, underfloor heating (the temperature of the coolant should not exceed + 450C). Standard dimensions: Ø outside 20 ÷ 110 mm, Ø inside 16.2 ÷ 90 mm, pipe wall thickness 1.9 ÷ 10 mm. Nominal pressure - 1 MPa.
- PN20 - this type of pipes is used in cold water supply systems in residential or industrial buildings or hot (up to + 80C). The service life is 25 years. The nominal pressure is 2 MPa. Dimensions: outer Ø 16 ÷ 110 mm, inner Ø 10.6 ÷ 73.2 mm, pipe wall thickness 16 ÷ 18.4 mm.
- PN25 is a polypropylene pipe reinforced with aluminum foil or fiberglass. Its properties are identical to metal-plastic. The service life depends on the pressure inside it and the temperature media. It is used in the installation of heating and hot water supply systems. The nominal pressure is 2.5 MPa. Dimensions: Ø outside 21.2 ÷ 77.9 mm, Ø inside 13.2 ÷ 50 mm, pipe wall thickness 4 ÷ 13.4 mm
The main advantages of polypropylene pipes
What are the indisputable advantages of polypropylene pipes? The technical characteristics of polypropylene, according to manufacturers, are truly amazing. It is considered a versatile building material for the installation and reconstruction of utilities in residential and industrial complexes. They have successfully passed tests in independent European and world laboratories and have confirming quality certificates. Consider the merits.
- Their main advantage is a long service life - about 50 years, and when used in a cold water supply system, they can serve up to 100 years.
- Thanks to the specially designed inner surface of the pipe, which is constantly in contact with water, no deposits form on their surfaces.
- Noise isolation. When transporting hot water from the heating medium or with a simple flow of water, noise can occur. Polypropylene is able to absorb them.
- Lack of condensation. Polypropylene PPR pipe is resistant to temperature changes due to its low thermal conductivity.
- Light weight. Compared to their metal counterparts, they are 9 times lighter.
- Ease of installation.
- No additional maintenance is required.
- Resistance to the effects of acid-base substances on them.
- The elasticity of the polypropylene pipe is very high.
- Affordable price.
Product data sheet pn25
Not so long ago, manufacturers developed and put into mass production a polypropylene pipe pn25. Its technical characteristics are described in detail in the product passport.
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Feature name |
Values for polypropylene pipes: dimensions |
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63 ÷ 10.5 |
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Internal Ø |
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Specific heat |
1.75 kJ / kg0C |
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Ø tolerance |
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Linear expansion, (1 / 0С) |
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Heating time during welding |
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Roughness factor (equivalent) |
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Cooling time, (seconds) |
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Tensile strength |
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Normative series |
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Elongation at break (relative) |
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Weight (kg / running meter) |
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Tensile yield strength |
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Melt flow (index) PPR |
0.25 g / 10 min |
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Thermal conductivity |
0.15 W m / 0C |
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Heating time during welding |
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Modulus of elastic layer PPR |
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Depth of the socket under the pipe (minimum) when welding |
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Pipe Density (Equivalent) |
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Volume (internal) running meter / l |
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Modulus of elastic layer PPR + fiber |
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Dimensional ratio (standard) |
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PPR density |
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Pressure (nominal), PN |
25 bar | ||||||
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The time of the welding itself |
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A novelty in the metal-plastic industry with high quality and properties - polypropylene pipe pn25. Specifications are detailed in the table above. It was she who was able to solve the problem with the high coefficient of thermal expansion of plastic pipe products. This makes it possible to use it in the drinking water supply system, hot water supply, heating installation and other utilities. And also for the transportation of other liquids or gases that are not aggressive towards the materials from which they are made.
Design features
The inner and outer layers are made of special PPR100 grade polypropylene. In it, the percentage of fiberglass fiber is at least 12%. The inner layer is made from the same material, but the fiber content is increased to 70% and also contains a red dye. The presence of fiberglass in the pipe reduces the level of deformation from temperature effects, but, unfortunately, cannot cope with oxygen diffusion.
What is the reinforcement of polypropylene pipes. Reinforcement types
Consider universal polypropylene reinforced pipes, their technical characteristics, types of reinforcement, where they are used. Special reinforcement makes it possible to use it in the heating system or hot water supply. In addition, they are not only famous for their long service life, but also for their high quality and efficiency. Today, there are two methods of reinforcing this type of product: fiberglass and aluminum. Let's consider each of them separately.
Glass fiber reinforcement
Fiberglass reinforcement is a three-layer pipe construction: two polypropylene layers (inner and outer) and a fiberglass layer. Marked as PPR-FB-PPR. This abbreviation in the marking confirms the monolithic structure and fiberglass reinforcement. During installation, these products do not need to be calibrated or cleaned; experts recommend installing more additional fasteners during installation.
Reinforcement with aluminum
Pipe products with such reinforcement are material for the installation of heating or hot water supply systems with a high level of structural rigidity. They are identical in strength to their thin-walled metal counterparts. Their surface must be marked PPR-AL-PPR. Reinforced with two layers of aluminum: the first is perforated with small holes, and the second is solid and solid over the entire surface of the pipe structure. When installing the heating, the pipe needs to be stripped of the aluminum layer, only the polypropylene layer is soldered. If the technology is performed correctly, then the mounted system will work for many years without problems.
Polypropylene and its use in the sewer system
So, we found out that polypropylene as a pipe material is highly resistant to aggressive alkaline and chemical substances. Therefore, to the question "which pipes are better to choose for engineering communications?" the answer is unambiguous - modern polypropylene sewer pipes. Technical characteristics: stability, strength and durability. In addition to resistance to the effects of aggressive substances on them, and there are a lot of them in the gutters, they will also last for a rather long period. They are not susceptible to the influence of corrosive processes in comparison with metal pipes. The length of the pipe for the sewer system is about 4 meters, the diameter of the polypropylene pipes (technical specifications contain such information) are from 16 mm to 125 mm. That is, the scope of their application in the sewerage system is quite wide. They are connected to each other by diffusion welding or using special fittings.
Valtec polypropylene pipes
Today there are a lot of offers from manufacturing companies of these products for buyers of our country. And when choosing a material for laying engineering systems, it is sometimes quite difficult to make a choice in favor of one of them. In appearance, they are absolutely the same, but differ only in manufacturing technology. And even then, if a person is incompetent in the issue of pipe production, then he is unlikely to understand the characteristics. This is especially true of new firms that have recently entered the sales market.
Italian manufacturers "Valtec" present their new Valtec polypropylene pipes to the buyer. Technical characteristics: excellent quality, new manufacturing techniques, durability and reliability. Moreover, this company has been occupying a leading position in the sales market for several years. Its products have always been and are in demand. The quality is high due to the fact that the company keeps up with the development of new technologies and implements them in its production. Manufacturers give a 7-year warranty for the product.
The price for the whole range of products is quite affordable. There are always available one-piece for cold water supply systems and composite reinforced with glass fiber or aluminum polypropylene pipes with a cross-sectional diameter of 20 ÷ 90 mm. The company's employees are very closely monitoring the quality of the products, so errors or deviations from standards are completely excluded. It is produced in special tubes up to 4 meters with printed markings, with accompanying documentation and certificates.
PPRC pipes
These are pipes made of high temperature polypropylene. They are produced with a section diameter of 20 ÷ 160 mm. Reinforced with fiberglass or aluminum. Their main difference is their low thermal expansion rates, low pressure loss. The production technology fully complies with GOST and the requirements of foreign standards. What are pprc polypropylene pipes? Specifications, properties and advantages of the plastic product: 
- low thermal conductivity;
- high level of sound insulation;
- resistance to corrosion processes;
- resistance to aggressive substances;
- high strength;
- resistance to bending more than once;
- environmentally friendly material;
- ease of installation;
- affordable price;
- long service life.
The use of polypropylene in the water supply system
Plastic pipe products rapidly entered the list of demanded building materials, and polypropylene water pipes are no exception. Specifications, advantages and disadvantages are presented below.
Advantages:
- resistant to corrosion;
- service life - from 50 years;
- zero conductivity, hygiene;
- ease of installation;
- do not require additional care;
- affordable price;
- the ability to withstand a pressure of about 20 bar;
- excellent thermal insulation.
Disadvantages:
- do not withstand temperatures over 1000C;
- lack of the possibility of repair or repair;
- welding work is required.
Available in different colors: gray, green, black and white. The color of the pipe does not depend on properties and quality, except for black. It has the ability to protect it from ultraviolet radiation. For the installation of the water supply system, pipes with a diameter of 16 ÷ 110 mm are used. For cold water supply, pipes marked PPH homopolymer or PPB block copolymer are suitable. PEX-AL-PEX pipes are used to supply hot water or heating. They are reinforced with either fiberglass or aluminum.
Classification of polypropylene pipes
All polypropylene tubular products are classified in a specific way. 
- PPB - marking means that these are pipes with increased mechanical strength, polypropylene pipes are used for heating. Characteristics: Reinforced (fiberglass or aluminum foil), strong, durable, affordable.
- PPH - marking of products with large diameters. They are used in ventilation systems or in cold water supply systems.
- PPR is the most popular and versatile brand. Its versatility lies in the fact that it is able to withstand high temperatures of water flow. Used in hot water supply and heating systems.
All these three brands differ from each other only in the type of plastic used in the manufacture. They contain special additives that make them more elastic and durable.
How are modern water and gas taps marked? e.g. DN 15, PN 40? what does 1-1 / 4, 1-1 / 2 mean?
Fast assistant
1-1 / 4 is called an inch and a quarter, i.e. 32mm. i.e. DN-32; 1-1 / 2 one and a half inches, i.e. 40mm. or DN-40. What DN what Du is nominal (conditional) INTERNAL! the diameter of the pipe hole, since the outer diameter of the pipe changes depending on the wall thickness. The wall thickness is dictated by the pipe application. (reinforced, normal, lightweight)
Uncle from the future ...
You have already been answered absolutely correctly to this question.
DN - nominal bore in mm (here 15)
PN - nominal pressure (here 4 MPa or 40 atmospheres)
fractions - thread size in inches (1 inch = 2.54 cm)
And there are also markings indicating the type of material.
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