Plastic tubes for heating: characteristics and pipe diameters

Heating systems for decades mounted using metal pipes - steel and copper. But pipes of ordinary steel have a number of serious shortcomings, and pipes made of stainless steel and copper in view of high cost is not available to all. These factors have led to the emergence of a new material with high characteristics - several plastic tubes varieties, which differ in terms of functionality and cost, but available for use in the home price range.

Plastic pipes for heating due to the specificity of operating conditions Tutor niche in the group of polymeric pipe materials, and therefore deserve special consideration.

Main article about polypropylene tubes.

Variations and general characteristics of the plastic pipe

Tubes of plastics - a material based on polymers, whose functionality relies on the basics characteristics. Plastic pipes are used for heating, hot and cold water, drain, ventilation, as liners and ducts for electrical wiring. Each area of ​​application imposes certain requirements to the material, so the characteristics of plastic pipes for heating specific. But while there are some common features, common to all varieties of plastic pipe.

Variety of plastic pipes

Polyethylene tubes (PE, Russian abbreviation - PE) - produced for mounting pipelines of high and low pressure (LDPE and HDPE pipe) used for inner and outer wiring of water supply systems, sewer and guttering, use is possible only as the supply line open expansion tank heating system for heating systems type.

XLPE pipes - a material made of polyethylene, in which one of the four ways is formed molecular "Crosslinking", increasing the strength by creating additional crosslinks between polymer molecules in grid. Used during installation of heating systems, as well as wiring circuits hot and cold water.

Polypropylene tubes (PP, Russian designation - PP) - group of several types of tube material based on polypropylene, the main characteristics of differing values ​​(working temperature and pressure). Widely used in heating systems, hot and cold water, drain and ventilation.

Pipes of polybutene (PB, Russian abbreviation - PB) - high-grade material, characterized by polypropylene increased flexibility, cold resistance value and the maximum working pressure.

Pipes made of polyvinyl chloride (PVC) - material of the two species (unplasticized and chlorinated) derived from vinyl chloride by polymerization.

Important! Due to the increased hardness and release chlorine upon contact with the hot medium PVC pipe for installation of heating systems, and GBS are not applicable.

Fiberglass pipe - tube wall of the ductile material are made of a fiberglass-based filler epoxy resins, in heating systems, these products have not found wide practical application due to time-consuming process connection.

Plastic pipe - products with a multilayer wall structure which provides high material specifications and widely used in heating systems, particularly when installing the warm floors.

General characteristics of pipes made of plastic

• Strength - the ability to withstand stress, typical for the conditions of operation of pipelines, including waterhammer.
• The plasticity and elasticity - preservation characteristics unchanged after deformation by the impact of pressure and temperature loads.
• Corrosion resistance - neutrality material manufacturing pipes to contact with moisture and dissolved compounds in it.
• Low thermal conductivity - the material along with the outer insulation is involved in the reduction of heat losses and condensation.
• Dielectric properties - there are no factors to static electricity and stray currents.
• Low friction - reducing the load on the circulation pump in overcoming the fluid friction against the inner surface of the pipeline wall.
• Resistance to biological attack - do not decompose and are inert to the presence of bacteria.
• The absence of limestone formations on the inner walls.
• Durability - due to the characteristics listed above.
• The high soundproof properties - the movement of the medium in the pipeline silently.
• Light weight - low transportation costs.
• Ease of installation technologies.

Plastic pipes for heating should possess all the properties, some of them listed above (Heat resistance, flexibility) - to a greater extent than, e.g., polyethylene or PVC products not suitable for heating systems.

Thus, from these types of plastic pipes in heating systems use only wiring of the following materials:

• polypropylene;
• a crosslinked polyethylene;
• high thermostability polyethylene;
• polybutene;
• metal and plastic.

To have an idea of ​​what is best for plastic pipes heating, consider the products from the list of materials in more detail.

polypropylene tubes

Polypropylene - a flexible and durable material rupture, which leads to its widespread use in the construction of pipelines. In products of this material are manufactured with a diameter of 16 to 110 mm, Labeling present Latin PP. High quality tubular material made of polypropylene was not immediately achieved. polypropylene melting point of 175 degrees at a value of 90 in the operating temperature. Admissible even transient operation of polypropylene at a temperature of coolant conduit 110 degrees, which means that the material is quite suitable for the heating apparatus. However, polypropylene has a high coefficient of thermal expansion, which means that conventional polypropylene pipe on the installation site will increase significantly in length when heated by passing hot thereon coolant. Besides, diameter of the pipe when heated also will increase, which will limit the use - covering tile finishing underfloor may crack or peel upon expansion of the base underneath heat lines.

Solution has been found reinforcement in polypropylene tubesWhich significantly reduced the thermal expansion of manufacturing the PP materials. Thus, polypropylene pipe products began to be manufactured in two basic types:

Reinforcement of polypropylene pipes

Fittings for PP-tubes made of aluminum or fiberglass which arrangement the pipe wall may be varied. Reinforcement aluminum also called stabilization and foil reinforced PP pipes - stabilized, therefore labeling of such products include the word Stabi.

As a result, the reinforcement wall PP-tubes are already multilayer structure not only different material layers, but their arrangement.

Execution reinforcing polypropylene pipe products can be the following:

• aluminum layer thicker wall closer to the outer surface - when welding aluminum shell of such products to be removed together with an outer layer of polypropylene;
• a layer of aluminum foil in the middle section wall - welding the foil is not removed on the tubes of such thickening section are formed;
• reinforcement layer of fiberglass fabric - a pipe with slightly larger than that of aluminum, the coefficient of thermal expansion, but simplified brazing process.

An aluminum foil layer has a thickness of from 0.1 to 0.5 mm - the thicker the foil, the higher the operating pressure of the pipe. Aluminum cladding, which not only increases the strength of the PP pipe, but is an oxygen barrier may be a continuous execution and uniformly perforated.

Polypropylene has the ability to pass oxygen through its mass, including those contained in the air. Consequently, the oxygen will flow through the pipe wall to the coolant. This is a negative factor when the heating system is used as an antifreeze coolant - some of its species form compounds damaging the boiler and the circulation pump in coordination with oxygen. For such a heating pipe should be mounted PP-tubes with solid aluminum reinforcement.

If, however, water is used as coolant, it is better to use a pipe with a perforated jacket for heating the conduit. Perforation of aluminum, which is performed through or embossed allows bonding adjacent layers of PP without using glue. Such polypropylene tubes minimally susceptible to thermal expansion and do not form thickenings on the temperature and barometric changes.

Recently, in order to stabilize the polypropylene steel pipe products used basalt fiber, known for its high temperature resistance and low thermal expansion coefficient. Examples are polypropylene tubes EKOPLASTIK production Czech reinforced basalt fiber by fusing a plastics which reduces the thermal expansion coefficient three times.

The magnitude of the allowable pressure and PP-pipe temperature are divided into the following groups:

• PN 10 - a thin-walled material for mounting the cold water supply systems with operating temperature up to + 20 ° C and floors with heated coolant to + 45 ° C, pressure of 1 MPa (10.0 kg / cm²);
• PN 16 - Pipe material for circuits hot and cold water with ambient temperatures up to + 60 ° C, pressure 1.6 MPa (16.0 kg / cm²);
• PN 20 - universal destination products, including GBS with temperature up to + 80 ° C, pressure 2 MPa (20.0 kg / cm²);
• PN 25 - reinforced aluminum pipes for hot water heating systems and devices with operating temperatures up to + 95 ° C, pressures up to 2.5 MPa (25.0 kg / cm²).

The magnitude of the nominal pressure is included in labeling articles, such as PN10, PN16, PN20, PN25.

For the installation of heating systems most widely PP pipe of the following sizes:

• 20 mm - for internal wiring network of plumbing and heating circuit system;
• 25 mm - for manufacturing risers in low-rise buildings, the connection of radiators and floor heating systems;
• 32 mm - for the production risers and the pipes for supplying a high-rise apartment buildings (floors 6 and higher).

Compound PP pipe heating systems

Compounds of PP pipes to perform the following types:

• one-piece - with the help of welding;
• Split - threaded connections.

When installing the heating hot water and is usually necessary to use both methods, since the connection pieces a conduit between the weld and the inset in the riser and connecting radiators - threaded connection.

Welding is carried out with a special tool - soldering weld which at the right using solid creates a sealed connection based on the penetration of the molecules of the contact surfaces each other.

The welding process PP pipes simple - skill acquired after several test compounds unnecessary scraps and couples gons laterals.

Screwing fittings are used which have previously been prepared for soldering welded shear the PP pipe.

Disadvantages polypropylene tubes

What it is called a disadvantage, often a feature of this material. And in the case of PP pipes. If considered as a lack of flammability, right furniture is also illuminated, especially made of natural wood, its naturalness but do not qualify as a drawback.

In general, do not have to deal with the shortcomings of tubular products made of polypropylene and low-quality products from certain the manufacturer, the wrong choice of material for the existing operating conditions and errors in installation, causes a claim to PP material.

The features of polypropylene pipes:

• Mounting brackets in the horizontal sections to avoid sagging supports spans step should be carried out, depending on the pipe diameter of 0.5 - 1.0 m;
• preparation of material joints before welding must be carried out carefully - removal of foil, trimming;
• welding PP pipes need to accurately maintain the warm-up of welded joints;
• insufficient flexibility neutralized using appropriate fittings (contours, easy bend);
• at purchase of material for the heating system installation acquire better pipe and fittings from one manufacturer;
• Avoid the use of PP-pipes of dubious quality, for example, even with subtle exterior defects.

XLPE pipes

To improve the characteristics of polyethylene (usually low pressure - IPA)

There is a special technology is changing its molecular structure, called crosslinking, creating additional bonds between molecules with increased strength and heat resistance properties of the polymer. XLPE pipes have PEX designation and have a solid wall or multi-piece sections - one or two shell made of a base material, and between them or outside the reinforcing layer is, performing the role of oxygen barrier.

The material has been successfully applied in many areas, including the wiring and heating systems, domestic hot water, normal and high.

Compound plastic heating pipes of PEX-material is performed by one of three methods:

• Crimping (Compression) - dismountable joint;
• The above press - conditionally demountable connection;
• electric welding - molded assembly.

Each of the methods of installation corresponds to a particular tool and fittings.

There is a method of crosslinking polyethylene 4, which after use of the resulting material is manufactured tubular products having labeling in corresponding designation:

Characteristics PEX-pipes crosslinking technology

At the tube material of PEX-a - uniformity of cross-linking and its a good percentage. Products made of PEX-and the most flexible of all the cross-linked pipes and a good molecular memory - the ability to restore its shape after deformation. This makes it possible to easily correct defects configuration and creases formed during the circuit assembly using conventional construction dryer.

PEX-a - long used crosslinking method that allows to obtain a material with a wide range of temperatures Operating retain their strength properties even at the peak of its short-term fluctuations from -100 to +100 degrees. Production of the peroxide-crosslinked polyethylene - the process expensive, but the high cost is justified by the quality of the finish product. PEX-a pipes have been successfully used for the installation of heating and hot water systems, maintaining their characteristics for many years.

With these virtues in PEX-a pipe has two significant drawbacks. During operation, the material is exposed to intense leaching of chemical coolant, which have a negative impact on the heating equipment and automation. In addition, the cost of this sort of cross-linked pipes, as well as fittings for it, far higher materials PEX-b and PEX-a. As a result, taking into account the cost of the work, the total cost of heating equipment XLPE polyethylene PEX-a may be several times higher than when using the products of other type of polyethylene crosslinking.

PEX pipes PEX-b began to be produced after the previous species, but 40 years of presence on the market - also sufficient time to evaluate the characteristics of the material. Production of PEX-b in great demand due to a combination of cost and availability of quality - high tensile strength.

Among the shortcomings of this type of pipe to be noted PEX- hardness and a low degree of molecular memory - the wrap material to give the desired configuration buhtovoy realization is difficult.

Crosslinking method PEX-c (radiation) irradiation of polyethylene produced beam of charged particles, wherein the portion of the existing links is destroyed to form a new. The method characterized by the inevitable non-uniformity of cross-linking, causing high risk of cracking, but the technology does not require costly, and pipe PEX-c is still available for systems with low requirements on the strength and heat-resistant harakteristikamteplovodov.

PEX-d pipes (nitric structure material) - production technology is complex and costly, while high cost of the material is not justified by the characteristics of the material, so the demand for the product is not high.

Polyethylene of raised temperature resistance

Material having marked PE-RT, was created as a more advanced alternative crosslinked polyethylene and represents thermoplastic, in which the manufacturing process is not chain-linking, which significantly boosts equipment. At the same time the strength characteristics PERT-pipes superior products PEX-polymer, and for convenience like compound - they can be welded joints. This also is due to the popularity of the material which by definition is suitable for mounting all the hot water supply and heating systems.

polybutene pipe

Tubular products of polybutene (PB, PB Russian abbreviation) - modern high-grade material that combines advantages of polypropylene and cross-linked polyethylene. The hot water and heating pipes of polybutene used relatively recently, but already proven material superior technical characteristics are identical for the application products.

Advantages of polybutene pipes:

• preservation of the strength characteristics at extreme temperatures;
• high degree of flexibility is maintained even at low temperatures;
• low coefficient of thermal expansion;
• possibility of assembly by welding joints;
• low thermal conductivity;
• resistance to chemicals.

Polybutene pipe products are manufactured in coils and bars, both conventional and pre-insulated performance. High performance is not only cause widespread use of polybutene in the heating and hot water systems, but their high cost to date.

Pipes made of metal

Metalloplastikovaja tubular products - a high-strength material with a wall consisting of 5 layers: aluminum tube with outer and inner shells XLPE fastened high-quality communication.

Execution of the outer and inner shells may be different crosslinking method or made of polyethylene of raised temperature resistance.

Pipe Production technology of metal complex, but is justified by the high costs on specifications the final product, which is produced with an outer diameter of 16 to 40 mm and a wall thickness of 2-3.5 mm, the form of realization - yardage bay.

Field of application of metal pipes - industrial and domestic heating and hot water supply.

Product Benefits:

• Anti-corrosion;
• internal and external resistance to chemicals;
• low thermal conductivity;
• low friction inner surface;
• small value of the radius of curvature at the bending assembly;
• anti-static;
• dielectric properties;
• dependability joints;
• durability.

Disadvantages:

• substantial quantity of thermal expansion (the need to install expansion joints);
• lack of resistance to mechanical damage;
• the need for tightening compression fittings;
• relatively low temperature resistance steel tubes;
• the high cost of valves and fittings.

Main technical characteristics of composite tubes are present in the marking material applied for convenience on each running meter.

Operational characteristics of metal pipe:

Important! When the coolant temperature above 140 ° C melts the inner polymer shell with the rest of the tube bundle structure.

Installation tube made of metal using special tools and fittings. If there are certain skills production assembly work possible device heating or CSAs of this stuff on their own.

conclusion

heating equipment housing success depends on many factors, including the correct choice of material for the heating pipe. Today's market of pipe materials is so rich, that allows you to choose plastic pipes for heating any heating unit. It should only have a clear idea of ​​the conditions of use mounted equipment.