Pipe material PND for water supply. Using PND Pipes for Water Supply Systems

To date, polyethylene pipes have been widely distributed in different areas. But most often they are used when installing outdoor water communications. Among the polyethylene products are the most popular pipes from low pressure polyethylene (PND). They differ next positive qualitieswhich is worth paying attention to their choice.

Advantages and disadvantages of PND pipes

Consider the main advantages of products made of low pressure polyethylene:

resistant to the destructive effects of corrosion;
low pressure polyethylene is resistant to aggressive chemicals, so such products can be operated in non-standard conditions;
when the fluid is freezing inside such a pipeline, the integrity of the walls is preserved;
polyethylene pipes for water pipes are characterized by good flexibility, which allows minimizing the number of connecting nodes in the design. The minimum number of compounds increases the overall performance of communication strength;
such products can be laid in seismic soils;
PND pipes for water pipes are quite easily mounted;
differ by a democratic value;
the operational period of such parts may reach the normal use of up to 50 years.

Like any other product, polyethylene tap pipes have some disadvantages:

have a weak resistance to the effects of ultraviolet radiation, so they are recommended to lay them in Earth or cases;
many types of waterproof PND tubes are not suitable for mounting water communications transporting hot water;
the strength characteristics of such products are lower than that of metal analogs.

Types and specifications of PND pipes for water supply

The range of PND products is quite diverse. They differ in purpose, and also have different specifications: diameter, length, etc. There are 5 main types of pipes that are performed from low pressure polyethylene:

SDR 9;
SDR 11;
SDR 13.6;
SDR 21;
SDR 26.

SDR indicator indicates which internal pressure can withstand water pipe. This indicator is determined on the basis of the ratio of the size of the product cross section to the wall thickness. The lower the SDR indicator, the thicker the wall in a particular pipe and, accordingly, it is stronger.

In addition, it is worth noting that low pressure polyethylene pipe can be two species:

PE 80;
PE 100.

The first option is used when laying water supply and other communications, the size of the cross section of which does not exceed 90 mm. The second option found its application in trunk structures.

And such products are:

pressure;
non-free.

The pressure pipe is used when installing gas and plumbing communications, the working environment of which is transported under defined pressure. Non-free PND products are used in the arrangement of self-sealing sewers, livnevok.

The indicator of the section of the waterproof PND pipes ranges from 10 to 1200 mm, however, the most popular sizes are products with a diameter of 20, 25, 32 mm. Such pipes are stored and transported in special bays (coils). Depending on the manufacturer and other conditions, their length can reach 25, 100, 200, and in some cases 1000 m.

Such products may have a blue or yellow strip depending on their destination. The blue bar means that this communication is manufactured for cold water supply. In turn, the presence of a yellow strip means that this item is manufactured for a gas pipeline.

Quality control PND pipes for water supply

Each pipe produced for water supply is mandatoryly checked for compliance. state standards Quality. Consider the basic parameters that are subject to verification:

first of all, a very important parameter is the state of the outer and inner wall of the product. The surface must be smooth, and also excludes any defects and marriage. It is allowed to preserve longitudinal strips and wavy areas that do not exceed the permissible norms for this product;
all surfaces, including the end, should not have extraneous inclusions, cracks or shells. The presence of the above flaws is considered a marriage. Sale and use of such products is prohibited.
the color of such pipelines should be black. It is allowed to have longitudinal stripes for which the purpose of products determine. The bands should not be greater than 3 and they should be evenly applied and distributed around the circumference of the product.

By purchasing plumbing pipes pipes, you need to pay attention to all the above moments.

For the average private plot (for example, in the country), it is recommended to purchase a coil with length of 25 meters. The wall thickness for the economic water supply should be approximately 2 mm.

Indicators of the cross section of PND pipelines can be different and selected on the basis of several conditions, however, the main parameter is the pressure in communication:

if the pressure in the water source is quite high, and its casing in diameter exceeds inch, then in this case the product is perfect with a cross section of 25 mm;
if a metal pipe with a diameter of no more than ¾ inch acts as a source of water, then it is necessary to use the part with a cross section of 20 mm.

It is worth remembering one important rule: the dimensions of the discharge cross section should be smaller than the similar indicator of the main pipe. This is necessary in order to create a good head in the system.

And of course, you should pay attention to the identification strip. The pipe must be suitable for economic (drinking) water supply.

Connections PND tubes

Docking two PND products with each other can be held in several methods:

welding;
compression fittings;
electromofold welding;
flange connection.

Welding. It is one of the most popular joint techniques. In addition, it is characterized by high reliability and tightness. The process itself is quite simple: the ends of the PND products are heated using special welding equipment, and then they are joined each other, resulting in an indefinite connection. Most often, such a dock is used when installing an underground water supply.

Compression fittings. The use of these connecting elements is a reliable and rather popular method when installing polyethylene pipesplates. To date, there is a huge range of compression details. The most popular among them are: clutches, tees, angular elements, as well as adapter fittings that allow you to transition to threads.

The use of compression fittings when laying water polyethylene pipes allows you to get the design of almost any configuration. Installation of communications connected by compression products is not recommended for the underground method. This is due to the fact that such a system needs periodic preventive inspections.

Electromofold welding. Such a connection is performed due to special fittings - couplings. These fittings are equipped with a spiral heating element and terminals. Terminals are necessary for connecting heating equipment. The welding process itself occurs: in the fitting on both sides, PND pipes are inserted, after which the welding equipment is connected to the terminals. The spiral element of the clutch melts its wall, as well as the walls of the pipes. As a result, it turns out a solid and hermetic indefinite connection. The welding mode is applied with marking on the coupling.

Flange connection. Such dock is used if you need to run to the thread. Flanges are not used as often as the above compounds, however, are indispensable in some cases. Flange compounds are quite popular when installing water PND pipes for cold water supply.

Currently, plastic pipes actively displacing competitors from other materials in the field of gas supply, water supply and sewage. One of the most popular goods on the market for water supply are PND pipes.

What is PND pipe?

It is deciphered by the PND as low pressure polyethylene. It was the polyethylene that became one of the first polymers used for the production of pipes. In stores are usually represented in the form of black bays, 25 or more meters, of different diameters.

Using

The polyethylene tube has been widely used in many areas: water supply, heat engineering and gas facilities, sewage and drainage, switching of commutations and as an external protective layer.

We are primarily interested in the installation and a water supply device using PND pipes. Black tube, with blue longitudinal stripes, with an inscription for drinking water and the specified diameter. Band of blue color Indicates that the pipe is intended for cold water supply. Pipes with yellow stripe - for gas.

Advantages of PND pipes in front of the metal:

Simplicity and light of installation;
Service life of about 50 years, which is 2-3 times more metal pipes;
A light weight;
Low thermal conductivity;
Ability to expand (pipe does not burst in the cold);
Operating temperatures from -20 ° C to + 40 ° C;
Low noise;
Wide selection of diameters and length.

How to choose a PND tube

Recommended parameters: Standard bays of 25 meters are ideal for the average country area, with a wall thickness of 2 mm. The diameter should be chosen depending on the water pressure in the system: if a common water supply or water source has a good pressure from a pipe of more than ¾ "inches, then feel free to take 25 PND tubes. If the water source is a metal pipe ¾ ", then the pipe is 20 mm. The discharge diameter should be less than the diameter of the main pipe to ensure good pressure.

Although the service life of the polyethylene tube is about 50 years, it will not be superfluous to pay attention to the production date, which is indicated by the labeling of the pipes together with the diameter and the wall thickness.

The outer diameter of PND pipes varies from 10 to 1200 mm, but the skewers are 20 mm, 25 mm, 32 mm.

Matching diameters

For fittings made of metal, and for a compound with a metal pipe ¾ inch (the inner diameter of 20 mm, the external approximately 25 mm) is 25 mm PND. Accordingly, the threaded compounds of the metal coincide with the PND pipe components.

Metal pipes and fittings with a diameter ½ inches (the inner diameter of 15 mm, an external approximately 20 mm) corresponds to the PND tube 20mm.

You should not forget that it is always possible to use adapters to reduce and increase the diameter of the component water supply system, however, with damage to the system.

Installation of PND pipes do it yourself

If you like to play the designer as a child, the installation of water supply with polyethylene pipes is not difficult. The pipe connection takes a few minutes and does not require the use of tools.

Possible options for connecting hoses and cranes to PND pipe

Draw a water pipeline in advance and the number of cranes required. Installation and laying under the ground is possible. It should be noted that the new one, just a detailed pipe, is trying to twist, taking the previous form. Therefore, one of the options for making installation is the fastening of the pipe with electric clamps to the old water supply or for the fence. Clamps recommend to take a width of at least 4 mm. Another option is to deploy and straighten the pipe before mounting, giving it somehow heavy in several places along the entire length and leave for a couple of days.

Types of fitting for PND pipes

To attach the PND pipe to the water supply system, thermal welds are used or threaded connections. Between themselves the pipes are joined by special clamping connections, which allows you to quickly replace the damaged pipe of the pipe or increase the length.

For a joint with a metal pipe or fittings with threaded compounds (Cranes or Congors), compression elements are used, from the back of which internal or external thread is made.

Compression tee - 2x tube joint and carving for connecting a crane or a clamping connection for removal of PND pipes. There are options for connecting the pipe removal of a smaller diameter.

A compression docking compound - serves to eliminate, extension of length or transition to a smaller diameter of the pipe.

Rotate 90 °

Compression crane

With proper compound, thanks to the design, the flows are excluded. At the joints of Metal - PND, we recommend using a fum-tape.

Let's try to figure out how "works" connection. The photo above shows a regular junction, thanks to which you can lengthen the pipe. Left revealed blue nut and clamping ring. It is thanks to the clamping ring that the pipe is tightly fixed in the connection. The ring is made of solid plastic with sharp notches, which, when twisting the nut, cut a little into the PND tube.

A white, translucent, sealing coupling, which, in turn, press the rubber ring, preventing water preventing water, is visible to the right of the connector. Below, in the photo, you can see all parts of a simple compound system.

The first "threshold" serves for the rubber ring and the coupling, the pipe itself comes to the middle of the junction.

Now the most important thing: the compound process. Pipe cut preferably with a smallcloth with a small teeth, cut off. Next, we unscrew the blue nut, let out all the details and we donate everything on the pipe.

The mistake of many people is that when installing, they do not disassemble the connection, and trying a little unscrewing the nut, drive the PNTU there with force. After that, the flows occur - the pipe is not deep enough into the connector.

The connector to the pipe is most likely as much as possible and tighten the nut until the strength is enough. Enjoy the result of the work!

Efficiency. During the construction of water supply networks using PND pipes, it is created to save up to 40% -45% of funds, comparing with traditional methods;
Durability. Lifetime of PND pipes - 50 years;
Unpretentious. Easy to maintain. Pipes do not need cathode protection, and in the investigation almost do not require maintenance;
Its manufacturability. Resistance to corrosion and chemical impacts. Polyethylene pipes are not interconnected with aggressive media;
Impact resistance and elasticity. Reducing the possibility of destroying the polyethylene pipeline during the freezing of the liquid, since the PND tube does not destroy, but expands in diameter, gained former size when the fluid is thawing;
Light weight, which greatly facilitates and reduces the cost of installation work;
Reliability. Welded seams retain their strength throughout the service life of pipelines from polyethylene pipes;
Preservation of polyethylene pipes;
Ecology. The inner layer of this PND tube does not give water any harmful impurities.

Pipes can be used for cold-range support, construction of irrigation and watering slightly patches.

Transporting pipes PND

PE pipe transportation easyness, due to pretty lung swelling. Not required loading and unloading equipment. The possibility of telescopic pipes.

Mounting pipe PND

The connection of the PND pipes is due to the electromobate, butt welding, as well as with the help of compression fittings.

Service life - 50 years.

Main technical characteristics

index SDR - 11, 13.6, 17, 17.6, 21 and 26;
material - low pressure polyethylene (PND);
marks of polyethylene -, and;
execution - commercial or ignorant.

Detailed technical characteristics - in each product card. There you can see the diameter (nominal, external and internal), weight of the route meter, wall thickness, etc.

PND plastic pipes for cold water supply are connected through fittings. Admissible electromobal and butt welding.

Comparatively recently, communication from steel and cast iron began to replace modern polyethylene pipes. They are widely used in drinking water systems in water supply and irrigation of suburban areas, with irrigation of agricultural areas, fire water supply and drainage systems.

Some features of polyethylene

the characteristics inherent in polyethylene pipes are due to the quality of the material used in the production of these elements. In most cases, pipes are produced from polyethylene of the following marks: PE100, PE80 and PE63.

The most dense and tough can be called PE100. This material has high tensile strength, but badly resists high temperatures, becomes more fragile.

PE80 is characterized by less density and durability, and also begins to melt at a lower temperature. However, this material has good plasticity and resistant to various types deformation.

If you compare some properties of polymers, steel and cast iron, then the following differences can be noted:

Steel is perfectly operated for 25 years, and polyethylene - half a century.
In relation to chemicals, the cast iron has no resistance, and the PND is considered highly resistant.
The level of wear resistance in the cast iron is quite low, the steel is medium, and the PND is high.
The strength to break the steel and cast iron has low values, and polyethylene reaches 20-38 MPa.

Positive characteristics of PND pipes

Plastic is an environmentally friendly material, which allows the use of products from it in systems that feed clean drinking water.

In addition to the total listed pipe polyethylene for hot water supply and various accessories from such polymers are distinguished by relatively low weight and accessibility, which makes more simple and fast assembly Hot and cold water systems.

Specifications of polyethylene pipes

After reading the designations on pipe products from PE, you can find out the following:

Who and when made pipes.
What brand of polyethylene produced products.
For which the pipes are intended.
SDR value.
What parameters have the walls of products, and what the diameter of the pipe is.
Regulatory document.

Depending on the values \u200b\u200bof the working pressure, which marks the normal functioning of the system, PND pipes for hot water Can be pressure, mid-condition and non-per-first. The temperature of the working medium is greatly influenced by its temperature.

Therefore, there are certain coefficients for reducing the pressure of the working medium with increasing its temperature:

At water temperature, no more than +20 0 ° C reduction coefficient is 1.
When the working medium heats up to 26-30 0, the coefficient is reduced to 0.87.
If water is heated to 36-40 0 s, then the coefficient is 0.74.

Polyethylene pipes can transport hot water, since it is withstanding the heating of the working medium to +110 0 C. The stability of the products to a lower temperature, -110 0 C, makes it possible to use such elements in systems operating at very low temperatures.

Polyethylene water pipe is produced with a diameter of 16-110 mm. For convenient transportation, the product is folded into the bay or coil up to 1000 m. Products big diameter, 110-1200 mm, cut into 12 meters slices. Low pressure polyethylene pipe products can operate under pressure in the range of 10-25 atmospheres.

Polyethylene pipes in water supply networks

For transporting drinking water, PE63 pipes are most often used, the diameter of which is not more than 60 mm, and the wall thickness does not exceed 4.5 mm. Such products can operate at a pressure of over 1 MPa. Application for these purposes of pipes from other polymers is not always effective, since in most cases the diameter of such products big sizethat complicates the installation of some systems, such as domestic water supply.

In the manufacture of PNDs, hot water pipes are most often used by improved polyethylene brands: PE80, PE100 and PE100 +. These high-tech products have additional labeling of PND - PE-RT pipes.

The most popular material can be called stitched polyethylene. Its products can be operated at a temperature of over 90 0 s without loss characteristic features And strength for a long time.

PE pipe for hot water supply may be one-layer and multi-layer. In the second embodiment, polyethylene properties are intensified by reinforcement aluminum foil, Steel or fiberglass. Water pipe for hot water can be made of PN20 pipes. In the manufacture of these products, a fiberglass layer is added, so they can operate under pressure up to 2 MPa and temperature within +110 0 C. PN25 pipes can also be used when mounting a hot pipeline (read: "). Products of this type are reinforced with foil, so the working medium may have a pressure of 2.5 MPa and the temperature to +75 0 C.

Installation of PE pipes for water

The installation of polyethylene pipes are carried out in accordance with their size and purpose of the system. The docking of the pipe elements is performed in the following ways:

Through welded or cast fittings, pipes are connected in places of turns and branches of the system.
The jack welding is used to connect polyethylene pipes, the diameter of which exceeds 110 mm.
Welding electrofold type use when working at low temperature mode.

Installation of hot water supply systems from polyethylene pipes has some features that need to be considered:

Systems are paved at a depth of no more than 0.2 meters below the level of primerization of the soil.
For convenient welding work, the trench width must exceed the diameter of the pipe by 0.4 meters.
When reverse filling of the water supply system first pour the sand layer with a thickness of about 0.3 meters, and the remaining place falls asleep with soil.

Fittings for connecting pipes must have the appropriate size and withstand a certain load.

Welding of polyethylene pipes

Using welding equipment creates in-point joints. In most cases, such technology is used to install pipelines, the operation of which implies high pressure. Tube products are joined by jacking, the diameter of which exceeds 50 mm.

The connection of pipe elements by the method of electrical welding is used when installing pipelines that will operate under pressure up to 16 atmospheres. The process of welding assumes the following actions: the clutch equipped with an electric heating spiral is put on the stripped ends of the pipes. When heated spirals, the polymeric materials of the coupling and ends are melted. After cooling parts, a durable and hermetic compound is formed.

The technical and operational characteristics of polyethylene pipes allow the use of products to assemble cold water systems, in which the temperature of the carrier does not exceed 40 0 \u200b\u200bC. Not all products from polyethylene are suitable for transporting hot water, these are due to their parameters. But a wide variety of pipe products, their simple installation and long exploitation makes the popular industrial systems and domestic destinationcollected from polyethylene pipes.

At all until recently, private houses, as well as multi-unit, had a heating system, as well as water supply systems, a system of sewers that were built on the basis of metal pipes. However, today steel products have sunk flew, and more practical plastic came to replace them.

What is so practical, if the metal is stronger, is it withstanding larger temperatures and so on? This question is quite natural, since we know about plastic quite a little, so we will try to figure out in detail in this topic.

What is the PND

Indeed, what is this material? Everything is quite simple. PND products are products made of low pressure plastic. Often have references to PE. In addition to the most common type of plastic - polyethylene, there is still whole line other species. Among them are polypropylene, polyvinyl chloride, and so on. One of the strongest is polyurethane, especially familiar motorists, since it is from this material that silent blocks are made, which even under conditions of severe loads are capable of serve five to seven times longer than their rubber analogues.

PND is nothing but polyethylene. Today makes it made a large number of Products for cold seasonal water supply cottage, constant water supply at home and so on. Polyethylene materials are used with pumping stations And without them. They apply to the purpose of watering the cottage, and in order to supply drinking water, as well as to protect the wiring.

As can be seen, there are a lot of applications. However, not all types of these products are suitable for all purposes. As with any other product, it has its own marking, which indicates a particular purpose.

Marking and characteristics

All plastic PND pipes for water supply have, as a rule, black or gray color. Black products with a blue stripe, or in rare cases, just blue are used for cold water supply.

Note! We must immediately make a reservation that for hot water supply such products do not apply. But why it will be understandable when considering the technical characteristics of this material.

Gray products are used in sewage, and those that have yellow stripes are in the gas liner.

Among other things, each individual product has its own designation, that is, the marking that is applied to the outer part. It may look like this: PE 100 SDR17 - 30 * 3.0 PN10. All these letters and numbers mean the following:

PE100 - polyethylene 100, that is, the polyethylene brand, which was used in the manufacture;
SDR17 is the value indicating the diameter ratio to the wall thickness. Physical meaning It does not matter because there is a relationship between such indicators, as the wall thickness and diameter, that is, produced products only with certain parameters, then this constant is simply to simplify the selection;
30 is an outer diameter;
3.0 - wall thickness;
PN 10 is the maximum pressure, which is expressed in atmospheric units at 20 degrees.

Some other specifications

So, besides the foregoing, polyethylene materials have such parameters with their values:

What is made - polyethylene;
For what are used - pressure and non-pressure pipelines, to create water supply (not hot) well, for watering the cottage section, for non-pressure sewers, to create gas highways, to protect the wiring and so on;
Coloring - blue and black with a blue strip are used for water supply (not hot), black with yellow strips are used for gas liner.
The service life is approximately fifty years. I must say that plastic materials when properly operation able to serve I. large quantity time;
Flexibility is quite high, which allows the installation of water supply systems even the most bizarre form;
Operating temperatures - not lower than -20 and not higher than 40. These are considered normal conditions. That is why for hot hot water supply such products are not suitable. They are afraid of such pipes, even not very hot water, therefore, the creation of heating systems and speech on their basis cannot be. Maximum on what can be calculated is on the installation of the summer shower for the cottage or the external watering system of the cottage;

Maximum temperatures. Despite the fact that the normal range of temperatures is considered from -20 to 40, polyethylene products are able to withstand and lower and higher indicators. The maximum value of a negative temperature at which the internal structure is not yet disturbed is -70 degrees. The maximum value of the positive temperature is considered to be 80 degrees. In some heating systems, the temperature of hot water exceeds 90 degrees, which once again proves that polyethylene materials cannot be used for this purpose;
Diameter. The diameter may be the most diverse. Industry produces pipes whose diameter lies in the range from 1 cm to 120 cm. In this case, special elements can be produced, the diameter of which sometimes reaches 1.5 meters, sometimes more;
The inner surface is completely smooth, which allows the use of a pump of lower power for watering, or for water supply. In addition, such a surface does not accumulate dirt and different deposits over time, so the inner diameter remains constant throughout the term of use;
Installation is carried out at once in several ways. The first is the welding of jack, and the fittings are not used. The second implies welding where fittings are used, or rather the coupling. The third method also implies that fittings are used - compression couplings. In addition, often such pipes are used for the purpose of the wellhead for giving. In this case, in the absolute majority, the installation will be carried out through a threaded connection;
As for the sizes, the segments of 12 meters are released, or bays with a length of 100 or 200 meters;
Pressure - from 6 to 16 atmospheric units.

Benefits in front of steel products

At the beginning of the article, it was about steel pipesAs the basis of all possible cool and hot water systems. The polyethylene pipes came to replace them. It will correctly identify the advantages that you have a younger material before you have already been tested by one-generation:

Since steel is much harder, then transportation costs more than about 2 times;
All for the same reason the installation of the PND is less costly, as it is possible to use fairly simple fasteners;
Since the installation of plastic, whether it is a watering system, or a water supply system, more simple, then the cost of it is less, and we are not talking about the actual costs of the products themselves, fittings and other materials, but on the installation, that is, on the works themselves;
Elasticity. This allows installation, turning the pipeline in almost any direction;
Easy installation reduces the timing of its completion;
Very high anti-corrosion resistance, that is, polyethylene products are not oxidized, do not rust and do not interact with water, with the exception of hot water;
No electric current, therefore, it is not necessary to organize electrical supplies where special fittings are applied;
Since the inner surface is smooth, and the inner diameter does not change, bandwidth about 10 percent higher than that of steel analogues;
Since the connection can be carried out through fittings, special skills are required for this. And if we are talking about the system of irrigation, it is all simple here - to connect the segments with the help of clamps, when we take into account that the inner diameter of one pipe will be the same as the external one.

Conclusions: As can be seen, low pressure polyethylene has become quite common because of its versatility. It should be noted that today they produce two main species that determine its scope: drinking and technical pipes. It is clear that the first can be used anywhere, including for watering a plot, feeding clean water, and so on. The second type of materials applies only for technical purposes, that is, the transportation of pure water is prohibited.

Since such products have a fairly wide range of temperatures and portable pressures, then operation does not require any care. However, for example, if we take an external watering system in consideration, then winter It is better to remove it, since the above values \u200b\u200bof maximum temperatures are implied by short-term effects. For the same reason, in hot water systems, this type of plastic is not used.

As for the installation, it really does not need to have any special skills. Fittings are sold along with the main products. Their use is pretty simple. In general, fittings plastic pipes They do not differ from the same components for steel, and the latter installation technology has been studied from beginning to end.

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