When buying pipes for the heating system should be oriented primarily to their durability and ability to withstand waterhammer and temperature changes. Another important factor is the ease of installation. So what better to choose the pipe for heating private houses? Tell us about it in detail.
Requirements for heating pipelines
According to the rules SNIP, the equipment used for the installation of heating systems must meet certain requirements:
- withstanding the operating pressure of 0.7-1.5 atm during the entire period of operation;
- maintain integrity during brief hydroblows at a pressure 1.5 times the nominal (working);
- remain tight when the coolant temperature 90 ° C;
- possess sufficient chemical resistance and resistance to ultraviolet;
- It is easy to install and maintain;
- have a shelf life of 25 years; and for pipelines laid in the hidden structure (walls, concrete floors) - not less than 40 years;
- the material used for their manufacture, must not contain any harmful impurities;
- to protect against rapid fouling of the system the internal surface of pipelines must have ideal smooth surface, for example for steel products equivalent roughness can be 0.2 mm;
- pipe diameter must be sufficient to provide heat to each of the heated space.
By the pipelines used for the installation of underfloor heating systems, there are additional requirements. Such products must be sufficiently flexible and elastic, easily stowed in the loop without forming wrinkles and well keep a predetermined shape.
Tip! For heating systems should be acquired and a connecting pipe fittings of the same producer. The properties of the materials used for their production, will be identical in this case. This will provide better sealing of joints.
steel
Which is better, a pipe steel for heating private houses or plastic? The advantages of metal products include high thermal conductivity, and the ability to easily release heat into the environment. Another undeniable advantage is the increased metal pipes durability, reliability, ability to withstand even considerable hammering, mechanical loading and temperature variations.
When heated, the thermal expansion of metal slightly, so the likelihood of leaks in the joints of the pipes is minimal. In the case of peremerzaniya allowed treatment with a blowtorch or other open flames.
But the disadvantages in many steel products. First - susceptibility to corrosion. Even galvanized pipes will last no more than 25 years. In the first years of operation is not satisfactory to them. However, during oxidation of the metal and appearance of rust buildup begin to clog the pipe. As a result, their capacity is greatly reduced. A similar problem - the scourge of steel products.
They are quite complex and installation - to bend the metal is possible only with special equipment when heated. Another drawback - the high thermal conductivity. For this reason, mount the metal pipes is not recommended during the installation of the electric boiler.
Are the steel pipe is slightly higher than similar products made of plastic. However, at their choice should take into account the cost and installation. After all, for welding metal it requires a considerable skill and expensive equipment.
Ideal for installation of heating systems and heating to steel pipes of stainless steel, capable to serve virtually forever. However, their use is limited because of the high price and complexity of installation.
HDPE pipes and crosslinked polypropylene
The term HDPE is used for articles made from high density polyethylene. Since this kind of plastic does not tolerate exposure to elevated temperatures (it is allowed operate only at + 40 ° C), the crosslinked polyethylene used for laying heating pipes (PEX abbreviation). its molecules additionally bind a three-dimensional network via cross-linking the thermoplastic material to reduce and impart strength. As a result, it is easy to tolerate elevated temperatures and capable of melt only if it exceeds over 200 ° C.
In addition to high heat resistance of crosslinked polyethylene products have the following advantages:
- lack of corrosion inherent in any type of plastics;
- increased strength and wear resistance: some manufacturers provide warranty for this material to 50 years under conditions at a nominal pressure of 6 atm and temperatures up to 70-90 ° C;
- ability to withstand temperature without losing tightness to -50 ° C; that is similar to the plastic tube is not afraid of even peremerzaniya;
- improved resistance to chemical compounds - such material is not able to enter into contact with them;
- elasticity: PEX pipes are flexible enough and is ideally suited for mounting of underfloor heating, they can easily be laid in loops without creases;
- ecological polyethylene does not emit harmful substances during heating;
- low price:
- easy installation: for welding of polyethylene used the simplest equipment, the cost is minimal.
Note that the crosslink density polyethylene molecules at can be different. Products marked with PEX-a are the most expensive. However, they have the maximum flexibility and are more suitable for underfloor heating. The area of molecular cross-linking of PEX-b is less, and the price is not so high. At the same time they are sufficiently reliable and perfectly respond to pressure differentials. But that's hard to bend them. Plastic PEX-a lower quality. It is quite flexible, but capable of forming creases.
Brass
Of course, the best pipes for heating systems is copper. Their main disadvantage is the considerable cost. The rest of the claims to a similar type of product, virtually none. They have:
- long life: because such material is not afraid of corrosion, the life of its products may be 100 years or more;
- high thermal conductivity;
- high-integrity compounds;
- ability to withstand high differential pressures, hammering and lowering the temperature to -200 ° C, its melting temperature is equal to + 1080 ° C;
- almost complete absence of obstructions;
- aesthetic appearance.
Connect the copper product by capillary brazing, or by compression fittings, threaded connection with rolling of. Copper is used for creating outlines underfloor. However, in this case a special kind of material - annealed copper. It is heated to a specified temperature and then quickly cooled. As a result, the pipe acquire greater elasticity and flexibility. This treatment is capable of slightly reducing the strength of the material, but to create an autonomous system of underfloor heating it enough.
Since copper is perfectly conducting, during assembly of pipelines it requires mandatory ground and installing insulating linings. Dangerous for this material are also eddy currents able to disrupt tight. Plus quite soft copper can be easily damaged, so when it is installed in the boiler will need to purchase protective covers.
Tip! Combining copper and one steel pipe is extremely undesirable. Steel immediately begin to rust. If you avoid such a compound can not, is mounted in front of steel pipes of copper (in the direction of working fluid flow). Brass reacts on contact with copper is less so in the absence of copper adapters better to use steel and brass fittings.
Polypropylene
Eco from this type of plastic products used for laying drinking water pipelines and pipelines of heating systems in private homes and apartments. We list the main advantages of this material:
- polypropylene has a relatively long life span (some manufacturers provide a guarantee of up to 50 years), so it is allowed to lay at the wall or walling in concrete floors;
- high chemical resistance, this material is non-corrosive, so sludge in smooth pipes is not formed;
- sufficient mechanical strength;
- minimal noise when passing the working fluid through the pipes (all metal products, unfortunately, this lack the dignity);
- monolithic solid compound by welding or fittings;
- for its welding uses inexpensive "soldering", where you can learn to work in the short term.
It should polypropylene is higher than the usual polyethylene, but less than the metal and plastic. Another disadvantage is the low temperature heat carrier - depending on the type of material use it is possible only at a temperature of + 65-95 ° C.
Note the markings. If you do not know which of the pipe is better to choose, it is better to stop on the copolymers PP-R and PP-RCT, having not only heat resistance (they can operate at temperatures up to + 95 ° C), but frost resistance. They are not afraid to lower temperatures. Plastic is labeled PP-C letters crystallizes upon freezing and become too brittle. Material P-H does not tolerate elevated temperatures, so it is not suitable for the installation of heating systems. Articles labeled PP-B are used for systems where a heating medium is heated to 50 ° C. More resistant to elevated temperatures RRRC material of the reinforcing layer.
metalloplastik
If you do not know what the pipe is best used for heating, buy metal and plastic. It is considered the best material for this purpose in the quality-price ratio. To impart enhanced stiffness plastic sheathing - a layer of aluminum, steel or fiberglass. The inner protective layer is made of smooth material, PVC, polypropylene or crosslinked polyethylene PEX, rust and lime so it is not deposited.
Reinforcement layer of such pipes to create a strong barrier to oxygen permeation. Due to this metallic elements (connecting fittings, pumps and so forth.) Is less subject to corrosion. Plus insertion of aluminum or steel significantly reduce the likelihood of thermal expansion and contraction of the plastic in the process of heating or cooling. Considered as the most stable products reinforced polypropylene or crosslinked polyethylene.
No corrosion and increased physical and chemical stability of the material allows to maintain at least 50 years. Metal-implemented coiled length 50-500 m. Therefore, it is quite possible to perform stacking with minimum connections, fittings and clamps rotation angles.
Just as propylene tubes, metal and are joined by welding or by releasable or conditionally releasable (compression) of the compounds. He is easy to bend, so the products made of it does not require a special fit. Such tubes are allowed to combine with the products of other materials via fittings.
Reduced service life is only possible with large pressure surges in the system and long-term use in excess of fluid temperature above 100 ° C. When operating in the normal mode it is able to last up to 50 years.
Vulnerabilities of this type is an adhesive product compound which is used for bonding layers of plastic and reinforcement. In applying compositions substandard manufacturer can bundle pipes and leakage.
