Pipes

Polyethylene pipes gost 18599 2001. Specifics. State standards

April 21, 2020

Currently, polyethylene is used to install high-quality and inexpensive water supply and sewerage systems (PE) pipes. These products confidently displace metal, asbestos-cement and other analogues. Regulates the production of polyethylene pipes GOST 18599 2001. This normative document also contains technical norms and requirements, presented to the final product.

Polyethylene pipes in many cases become an excellent replacement for heavy metal products

Features of polyethylene pipes

All polymer pipes have common technical and operational characteristics. However, despite this, certain types of products of this type have their own characteristics. The distinctive properties of PE products include: warranty period of operation of a polyethylene pipe of GOST 18599 2001 is 50 years and improve over time the properties of the transport of the working environment.

The capacity of a polyethylene pipeline increases for two main reasons:

  1. The boundary layer of the polymer swells over time. As a result, there is a specific effect of surface elasticity, due to which the resistance to movement decreases, and improving the flow conditions of the pipe walls.
  2. Corrosion overgrowth of a metal pipe reduces its inner diameter. However, due to the characteristic polyethylene creep properties, through section of the product, made of this material, in the course of operation increases not to the detriment of its working capacity. In numbers, the increase looks like this: close 10% during the first 10 years and about 3% throughout the life of the pipeline.

A wide range of operating temperatures is another important advantage. Polyethylene pipe, that meets the requirements of GOST 18599 2001, does not lose the operational characteristics at considerable negative temperature (-70?WITH) and retains strength at +60?WITH. If this mark is exceeded, the strength of PE decreases, and it loses its ability to withstand high pressure.

Resistance to high pressure and low temperatures allows to apply polyethylene pipes for laying of underground networks without any isolation

The coefficient of reduction of the value of this parameter made of polyethylene pipes depending on the temperature of the working medium is presented in table №1.

Table 1

Fluid temperature ?WITH Coefficient of pressure reduction, Ct.
PE 100, PE 80 PE 63 PE 32
36-40 0,74 0,62 0,3
31-35 0,8 0,72 0,47
26-30 0,87 0,81 0,65
21-25 0,93 0,9 0,82
Less 20 1,0 1,0 1,0

Elasticity of pipes, in addition to ease of installation, has a positive effect on the transportation of these products. Deliver pipes to the consumer, whose diameter is not more 160 mm, allowed by bays longer than 200 meters. They can be cut with an ordinary hacksaw. Engineering networks are assembled from such pipes by means of special couplings, fittings and other details.

Importantly! Exposure to direct sunlight causes the aging of polyethylene. Therefore, polymer pipes should be used in external communications, stabilized with soot.

State standards and their requirements

Technical characteristics of polyethylene pipes are regulated by the following regulatory documents:

  1. GUEST 18599 2001. It contains requirements for pressure PE pipes, used to transport water (including domestic and drinking water supply) with temperature 0?T?40 ?WITH. This Guest does not apply to tubular polymer products, designed to move flammable gases and to perform electrical work.
  2. GUEST 22689 89 describes the characteristics of pipes and fittings for them, made of LDPE and HDPE (these abbreviations denote, in accordance, high and low pressure polyethylene). Only those products are subject to this standard, which are used in internal sewerage systems of buildings with the maximum constant temperature of drains +60 degrees and short-term (to 1 min) +95 ?WITH.

Pipes with thick walls and large diameters do not fold into bays, and are delivered only by direct segments of standard length

Melt fluidity, determined from the material of the finished product, should be no more than 2g / 10 minutes. The surface of the pipes must be smooth and even. On the outer surface is allowed the presence of traces no larger than 0,5 mm from the calibrating and forming tool. Pipes of this type cannot be rolled up in bays. GUEST 22689 89 does not regulate deviations from straightforwardness.

After heating the pipes, the change in their size in the longitudinal direction should not exceed 3%. These products should not crack in a 20 percent solution of the excipient OP-10, specified in GOST 8433 81, for 24 hours after heating to 80 ± 3 degrees. Connection of PE GOST pipes 18599 2001 with shaped parts will be considered airtight, if the internal hydrostatic pressure test is successful 1 kgf / m2 (0,1 MPa) at temperature +15 ± 10 degrees. Pipes, as well as shaped parts must be made of HDPE melt with fluidity index, determined by GOST 16338. If the raw material is LDPE, then the value of this parameter is regulated by GOST 16337. In generalized form, the range of values ​​of the fluidity index is as follows: 0,25? PT ?1,5. Unit of measurement - g / 10 min.

GOST R 50838 from 1995 provides for the production of polyethylene gas pipes in the bays, straight segments and coils. But with one clarification: products with a diameter 225 and 200 mm are available exclusively in segments, the length of which can vary in the range 5 ?L?24 meters with the multiplicity of the step of adjacent values 0,5 m. Permissible deviation of length from face value - no more 1 percent.

On a side note! In one batch of GOST 18599 2001 allows the presence of long pipes 5 3 ?L ? 5 meters at least 5% of the total.

Regarding the manufacture of bays and coils, the marginal deviation rate is as follows:

  • pipe length up to 500 mm - no more 3 percent;
  • length of pipes from 500 mm - no more 1,5 percent.

Length of pipes, supplied in bays, may differ from the standard in agreement with the customer

Production of polyethylene pipe products of other length and with other maximum deviations is allowed only in agreement with the customer. The indicator of the minimum long-term durability depends on type of a product and is used at calculation of working pressure of the pipeline. Its designation contains 3 Latin letters MRS, followed by numbers. Polyethylene of the PE brand 100 corresponds to the MRS label 10,0 MPa, PE 80 — MRS 8,0 MPa and PE 63 — MRS 6,3 MPa.

Differences of brands

For the first time for the production of polymer pipes was used PE 63. Its rather high short-term strength is not able to offset the low resistance to cracking. in addition, during long-term operation, the strength properties of the material are significantly reduced. Therefore, currently the production of pressure pipes made of PE 63 according to GOST 18599 2001 sharply decreased. Today, consumers respect PE products 80 and 100, and the latter are the most popular. This is due to the following factors:

  1. Higher, than in PE 80 density allows to let out pipes with smaller thickness of a wall, not to the detriment of the ability to withstand a given operating pressure.
  2. Bandwidth on 20 percent higher, and pressure loss on 30 percent less, than PE pipes 80, has the same nominal diameter.
  3. Weight of one running meter per 20% Less, than PE pipes 80, withstands the same pressure. This factor reduces the cost of transportation and installation of pipelines.
  4. Indicators of resistance to fast and slow cracking several times exceed these characteristics of similar products from PE 80.
  5. Higher frost resistance and resistance to various mechanical damage favorably distinguishes PE pipes 100.
  6. In the production of large cross-section pipes made of PE 100 there is a significant reduction in material consumption by reducing the outer diameter without loss of capacity.
  7. Z PE 80 mainly small diameter pipes are produced.

High-strength pipes are made of PE polyethylene 100

Advantages over steel pipes

As mentioned above, polyethylene pipe is guaranteed to last at least 50 years. This service life is possible due to the following properties of PE / pipes:

  • no need for cathodic protection, due to these products are practically maintenance-free;
  • high chemical and corrosion resistance. Polyethylene pipes are not afraid of contact with aggressive environments;
  • the possibility of scale formation on the inner surface is excluded;
  • low thermal conductivity reduces the level of heat loss and reduces the formation of condensate on the outer surface;
  • even if it is in a polyethylene pipe, the liquid will freeze, it will not collapse. The pipe will simply expand, and after thawing the working medium will acquire the same size;
  • low modulus of elasticity reduces the risk of water hammer;
  • welds of joints remain reliable throughout the service life of polyethylene pipes (GUEST 18599 2001);
  • butt welding is easier, requires less time and is much cheaper;
  • multiple re-assembly is possible;
  • polyethylene pipe - a reliable shield against bacteria and microorganisms. Construction and reconstruction of engineering networks using pipe products of this type is cheaper than 40 % compared to traditional methods.

Importantly! Polyethylene pipes weigh in 5-7 times less, than steel. Therefore, the small movements required during their installation are performed without the use of lifting mechanisms.

One of the main advantages of PE pipes is the ease of installation as in the home, and industry

SDR of polyethylene pipes

Buying such products, pay special attention to the markings applied to them. It contains the following information about a specific pipe:

  • information about the manufacturer;
  • Guests, according to the requirements of which it was manufactured;
  • brand of polyethylene, example, PE 100;
  • the thickness of the material of the walls of the product and its diameter;
  • abbreviation SDR, followed by a certain index. This is a transparent indicator, which provides the most accurate information about the capabilities of pipe products

The abbreviation SDR comes from the English term Standard Dimension Ratio, which in translation sounds like this: Standard Dimensional Coefficient. Its value is calculated by dividing the outer diameter by the wall thickness of the polyethylene pipe GOST 18599 2001.

SDR = Outer Diameter / Wall Thickness.

A simple analysis of this formula says, that products with a lower SDR index have thick walls, and, vice versa, thin-walled pipe corresponds to a larger value of this index. Differences in "pressure classes" of such products depending on the SDR are presented in table №2.

Table 2

SDR 41 SDR 33 SDR

Twenty-six

 SDR

Twenty one

 SDR

17,6

 SDR

Seventeen

 SDR

13,6

 SDR

Eleven

 SDR

Nine

 SDR

7,4

 SDR

Six
4 atm. 4 atm. 5 atm. 6 atm. 7 atm. 8 atm. 10 atm. 12 atm. 16 atm. 20 atm. 25 atm.

In general, this figure, along with the thickness of the polyethylene layer indicates the level of load or pressure (internal and external) able to withstand GOST polyethylene pipe 18599 2001.

Pressure networks require the use of pipes with SDR 6-9

It is recommended to use this standard dimensional factor when determining the suitability of the pipe for the implementation of a particular system - pressureless and pressure, namely:

  • pipes with SDR 6-9 in addition to water supply are suitable for the installation of pressure collectors of sewers and even gas pipelines;
  • ware, indexed from 11 up to 17, can be used to create low-pressure plumbing, as well as irrigation systems;
  • polyethylene pipe products with SDR indicators 21-26 can be used to organize low-pressure indoor water supply of multi-storey buildings. A, example, PE pipes 100 SDR 26 found application in the food industry: the juice is transported behind it, milk, beer or wine;
  • pipes with SDR 26-41 used for self-flowing (безнапірні) sewer branches.

Importantly! Accounting for polyethylene brand is one of the most important conditions for the correct choice of pipes made of it. Even with the same SDR, product, in the labeling of which there are more, example, PE 100, and not PE 80, will be more resistant to various mechanical influences.

Here are some examples, concerning the use of PE pipes 80 stamps.

  1. PE pipes 80, SDR 21 characterized by low strength under internal pressure and compression. Therefore, it is not recommended to use them for a gas pipeline device, burial in the ground and for pressure systems.
  2. PE products 80 with SDR index 17 are recommended for installation of water supply systems of low-rise buildings. For this, their level of strength is quite sufficient. And to save on installation will allow low weight and low cost.
  3. PE pipe 80 with SDR 13,6 very strong and can be used to build a long-term water supply system.

The pipe with low strength is only suitable for use in low pressure networks, example, in the irrigation system of the country site

HDPE pipes

Basic standards for pipes, made of low pressure polyethylene, described in Guests 18599 2001.

Manufacturing technologies. According to this normative document, it is not necessary to use any polyethylene for the production of these products, but only obtained during the polymerization reaction under low pressure. Its production is performed in special chambers, in which a constant value of this parameter in the range of atmospheres is maintained. A characteristic feature of the manufacturing process is also the stabilization of the temperature near the mark 150?WITH, and not just control of pressure constancy.

Today, two methods of production of HDPE pipes GOST are used 18599 2001:

  1. Rotating mold casting technology. The tubular configuration is obtained by distributing the molten polymer under the action of centrifugal force - it sticks to the surface of the walls of the mold.
  2. Extrusion. The product is made by extrusion from molten granules. The tubular structure in this case is formed by the extruder head: through it the screw press pushes the overheated polymer. This process is easier than casting. However, in the first case, the dimensions of HDPE pipes GOST 18599 2001 are more accurate and with minimal deviations from the oval.

As for the weight characteristics, then their numerical value does not depend on the manufacturing technology. This is due to the absolute correspondence of the dimensions of the final product of the figures, specified in Gost 18599 2001. After all, the share of raw materials in any case is the same.

Most HDPE pipes are made by extrusion

To get an idea of ​​the mass of HDPE pipes depending on the diameter and SDR index, read the data presented in table №3.

Table 3

Diameter, millimeters SDR 26 SDR 21 SDR 17, 6 SDR 17 SDR 13,6 SDR 11
Six hundred and thirty Forty six 56,50 66,60 69,60 84,80 103,0
Five hundred and sixty 36,30 44,80 52,60 55,0 67,10 81,0
Pyatsot 29,0 35,80 42,0 43,90 53,50 64,70
Four hundred and fifty 23,50 29,0 34,0 35,50 43,30 52,40
Four hundred 18,60 22,90 26,90 28,0 34,20 41,40
Three hundred and fifty-five 14,60 18,0 21,20 22,20 27,0 32,60
Three hundred and fifteen 11,06 14,2 16,70 17,4 21,30 25,70
Two hundred and eighty 9,09 11,30 13,20 13,80 16,80 20,30
Two hundred and fifty 7,29 8,92 10,6 Eleven 13,4 16,2
Two hundred and twenty-five 5,880 7,290 8,550 8,940 10,90 13,20
Two hundred 4,680 5,770 6,780 7,040 8,560 10,40
One hundred and eighty 3,780 4.660 5,470 5,710 6,980 8,430
One hundred and sixty 3,03 3,710 4,35 4,510 5,5 6,670
One hundred forty 2,31 2,8 3,35 3,5 4,22 5,1
One hundred twenty five 1,83 2,3 2,66 2.8 3,37 4,1
One hundred and ten 1,42 1,8 2,1 2,16 2,6 3,14
Ninety 0,969 1,2 1,4 1,5 1,8 2,12
Seventy five 0,668 0,82 0,97 1,01 1,230 1,46
Sixty-three 0,488 0,573 0,682 0,72 0.87 1,05
Fifty 0,308 0,37 0,44 0,449 0,55 0,663
Fourty — 0,24 0,281 0,293 0,353 0,43
Thirty-two — — — 0,193 0,228 0,277
Twenty five — — — — 0,147 0,168
twenty — — — — — 0,116

Council! If you intend to use products of this type for hot water supply, when buying, pay attention to their labeling. It must contain the following sequence of letters: PE-RT.

Cross-linked polyethylene and the advantages of pipes made of it

In recent years, low-temperature heating systems have become especially popular. This phenomenon is due to the appearance on the market of relatively cheap and reliable cross-linked polyethylene pipes.

Cross-linked polyethylene is one of the most reliable materials for heating installation

This material is the most dense modification of the polymerization product of ethylene, characterized by a reticulate molecular structure, strengthened by additional intermolecular bonds. It is denoted by the following Latin letters: PEX. The first two, as it is easy to guess, denote polyethylene, and the last - X - just says that it is sewn.

Conventional polyethylene is a collection of large polymer molecules with numerous side streams, most of which "float freely" in the intermolecular space. "Stitching" forms additional connections, creating, in turn, particularly strong structure - intermolecular network, similar to the crystal lattice of solids. The use of different "crosslinking" technologies allows to obtain a substance with fewer or more such bonds and, in accordance, with greater or lesser strength characteristics.

  • PEX a - is characterized by the highest percentage of crosslinking. The number of crosslinked molecules can reach the mark 85%. This peroxide polyethylene is obtained in the presence of hydrogen peroxide molecules.
  • PEX b - the volume of the associated structure is 70%. This polyurethane polymer is the most common and is used in a wide range of items, sold in today's market.
  • PEX c - stitched to 60 percentage of molecules. It is made by a radiation method.
  • PEX d - crosslinking reaches 70%. It is created in the presence of nitrogen molecules, and the conditions of the reaction are more complex.

In terms of technical characteristics, cross-linked polyethylene is comparable to many solids. And behind such parameters, both service life and resistance to various destroyers, even surpasses some of them. Of course, not all brands of cross-linked polyethylene can compete on an equal footing with the materials traditionally used for the manufacture of heating and water supply pipes. This is primarily a PEX product. It is characterized by the greatest impact resistance, resistance to cracking and the highest melting point.

Due to the strength and high flexibility of PEX pipes, they are one of the best options for underfloor heating systems.

Useful Information! High-percentage crosslinking gives less ductility and harder products. This factor does not mean, that she is the best. Simply with its help it is possible to receive materials of various quality for production of products of various function.

Given the above, cross-linked polyethylene pipes have the following advantages:

  • shape stability. If such products will not be affected by external loads, they do not deform even at temperature +200?WITH;
  • high fatigue strength. This property is preserved during transportation of the working medium with temperature +95?WITH;
  • resistance to cracking. High toughness and the same impact strength in places of cuts is fixed even at considerable negative temperatures (-50?WITH);
  • optimal ratio of flexibility and strength;
  • absence of heavy metal ions and halogens;
  • corrosion resistance;
  • ability to resist the effects of chemically active compounds;
  • excellent shrinkage qualities of the material;
  • high wear resistance: the surface of the cross-linked polyethylene pipe is slightly abrasive.

Welding of polyethylene pipes

Welding is considered to be the most reliable way to connect the elements of polyethylene pipes. Knowing the methods of its implementation will allow you to choose the most appropriate equipment.

Butt welding. This method is used, when the walls of the pipes are thick 5 mm, and the diameter of their products exceeds 5 cm. The ends of the products are heated to the desired viscosity due to contact with the heating element - the stove. After combining, a very reliable fixation of the back is obtained, that the process of compound formation takes place at the molecular level. Butt welding technology is not difficult to call. Realize it under the power of their own hands to any homemaker. However, without a special unit for welding polyethylene pipes can not do here. If you do not plan to lay pipelines from such polymer regularly, the device can simply be rented, instead of buying it.

Butt welding provides a reliable and durable connection, but it requires a special unit

The sequence of stages is as follows:

  • place the ends of the pipes in the appropriate welding machine;
  • install the above-mentioned heating plate between them;
  • press the ends to it under low pressure;
  • we are waiting, until they melt to the required level;
  • reduce the pressure and allow the elements to finally warm up;
  • remove the plate;
  • connect both pipes under pressure;
  • we are waiting for the joint to cool down and the joint to harden completely.

Importantly! Manipulate the hob as smoothly and carefully as possible. Otherwise, you risk disrupting the formation of heated molecular bonds.

Today in construction stores you can buy the following types of welding equipment for welding plastic pipes:

  • mechanical welding machine. Provides for all actions to be performed manually;
  • units with hydraulic drive. Thanks to hydraulics, it takes less effort;
  • modern software-controlled devices. Being fully automated, these devices will accelerate significantly, and most importantly to facilitate the process. Of course, their cost is quite high.

Experts note the following advantages of butt technology:

  • errors due to inexperience and the human factor in general are excluded. As a result, the connection is very good;
  • process automation (this applies to hydraulic and software-controlled equipment for welding polyethylene pipes);
  • possible control during the performance of works.

Butt welding of polyethylene pipes will be high quality and reliable with the correct execution of all stages. Data from experiments conducted by independent organizations show, that the strength of the correctly formed weld in 8 (!) times higher than the similar characteristics of the pipes themselves.

One of the options for welding polyethylene pipes is to connect them with electric couplings

Rules, which must be guided by butt welding, very simple.

  1. Work should be performed only on flat and hard surfaces, example, on a reinforced concrete basis, asphalt or boards. An important point - compliance with the alignment of the pipes. The deviation of the axes should not exceed 10 percent of the thickness of their walls.
  2. Plugs should be inserted at the back ends. This ensures the absence of draft of the pipe cavity and the constancy of the set temperature of butt welding.
  3. Before, how to fix the ends in the clamps, wipe them inside and out with a lint-free cloth. Perform a similar procedure with the hub clamps
  4. Fix the pipes in the chassis as follows, that their marking was located along one line and was from above.
  5. First, than to get started, wipe the welding equipment. Conducting a test joint will remove dust and microparticles from the heater. When working with pipes, whose diameter exceeds 180 mm, perform two test joints.
  6. Before welding pipes with different diameters, allow the heater to cool, and then make an additional test joint.
  7. You only need to start a new connection, when you make sure that the segments of the pipeline are already connected.
  8. Grinding of joints is necessarily preceded by the procedure of cleaning the grinder discs from previously adhered to their surface polyethylene particles.

Importantly! Remove chips from the ends and chassis should be a non-metallic stick. Doing so with your hands is strictly prohibited.

Electric coupling welding. This method involves the use of a welding machine and special electrical couplings. It is relevant when installing long pipelines, when butt welding is not possible.

The work must be carried out in this sequence:

  • workplace preparation;
  • selection of the appropriate fitting;
  • cleaning of the connected details from pollution;
  • trimming the ends of the pipes with the subsequent removal of the oxidized layer;
  • fixing of polyethylene pipes and fittings in the device-positioner;
  • switching on the welding unit and waiting for the operation to end;
  • the equipment must be switched off when finished, and check the quality of the seam.

During the visual inspection, pay special attention to the following points:

  • the edge of the seam should protrude above the outer and inner surfaces of the pipes in the form of a roller;
  • the optimal height of these rollers is close 2,5 mm at wall thickness, not exceeding 5 mm. This figure for more massive samples - no more than the same 5 mm;
  • the displacement of the pipes should not be more 0,1 percentage of wall thickness.

Design and dimensions of the welding machine, necessary for installation work, depend on the diameter of the PE pipes

Under these conditions, the connection will last more than a decade.

Design features of equipment for welding HDPE pipes

The welding unit consists of the following three main components:

  • bed. It has a hub for a clamp, by means of which the necessary effort in end faces of pipes is created. This element can be actuated hydraulically (using a special device) and mechanical (that is, manually) driven;
  • butcher of electromechanical type. It is intended for alignment of end faces of pipes just before procedure of their heating;
  • heating element. In the slang of professionals, it is called nothing more than a frying pan. With its help the ends of pipes are heated and melted.

It was said above, that today there are several types of equipment for welding HDPE pipes. Their features are as follows:

  • use of installations with the drive of hydraulic type allows to weld butt of a pipe of practically any diameter;
  • units with mechanical drive. Such equipment makes it possible to carry out butt welding of pipes with a cross section up to 160 millimeters. It is characterized by one of the best value for money;
  • welding mirrors. With their help it turns out very inexpensive welding. But given that, that in the device there are no tortsavatel and the centralizer, it is not necessary to use it for welding of pressure head pipelines.

The following units are the most popular.

НЕ200. This heating device allows to work with products with a diameter no more 20 div. High-quality connection provides anti-stick coating.

R 63 E. It is used only in the home for welding any plastic, including HDPE pipes, whose diameter does not exceed 63 mm Equipped with display with temperature controller.

ROWELD R. 355. It is intended for welding of pipes in diameter 90 ? D ? 355 mm

Useful Information! Due to its large size, this model is used mainly in the field of industrial production.

ROWELD ROFUSE BASIC. Is a household analogue of the above unit. It has the ability to control any stage of work and is characterized by high security.

Of course, this is by no means a complete list. The rich nomenclature of commodity positions in this segment of the domestic market will allow to pick up a sample, fits your conditions.