Plastic (metal-polymer) and polypropylene pipes (PP or PP) do not rust, do not degrade the quality of water, simply cut and mounted on the inner surface at the expense of smoothness is not delayed deposits. Therefore, this kind of products are often used for central heating systems, water supply. Simple buyer to distinguish them by their appearance, do not understand the labeling, it is difficult, but products from PP lighter and stiffer (do not bend). It is better to buy - metal or plastic pipes?
metallopolimernye
Metal-plastic - material consisting of a combination of layers of thermoplastics and aluminum foil. Metal provides rigidity plastic - corrosion resistance, antisoiling properties, attractive appearance. Thermoplastics are capable upon heating and cooling repeatedly without loss of properties soften and become rigid again. This property allows to use them in the manufacture of pipes for hot water supply and heating systems.
The tubes of Metal aluminum layer is between two layers of cross-linked polyethylene (PE-X grade or PE-RT). Aluminum welded segments "overlap". For connecting the metal and plastic layers in a single unit using the heat-resistant adhesive.
Main characteristics plastic pipes:
- Operating Temperature - + 75 ° C;
- maximum temperature (peak) - +110 ° C;
- operating pressure at + 75 ° C - 1 MPa, at + 20 ° C -2,5MPa;
- thermal conductivity - from 0 39 to 0 45 W / mK;
- deadline for hot water service systems 25, cold - 50 years (required compliance operation mode);
- diameter - 16, 20, 26, 32 mm (larger products found on sale rare).
polypropylene
Polypropylene (grade PP-R, PPRC) - one thermoplastic polymer. For strength, the hardness of the tube made of him, ahead of metal-in appearance - not inferior.
PP pipes are of two types:
- unilamellar (without reinforcement) - only from polypropylene;
- sandwich (with reinforcement) - a layer of PP, a fiberglass layer or an aluminum foil, another layer of polypropylene.
Main technical characteristics of polypropylene pipes:
- Operating Temperature - + 75 ° C;
- Melting point - +146 ° C;
- operating pressure at + 75 ° C - 1 MPa, at + 25 ° C - 10, 16, 20 or 25 bar for selection (in view labeling 1MPa = 10 bar);
- the thermal conductivity coefficient (depends on the diameter) - from 0,15 to 0, 23 W / mK;
- period of service hot water piping 25, a cold - 50 years (required compliance operation mode);
- diameter - 16, 20, 25, 32, 40, 50, 63 and 76 mm.
similarities
Common shortcomings of polypropylene pipes and metal pipes:
- The large linear expansion coefficient. of the PP pipe length can be increased by a few centimeters due to expansion when exposed to high temperature (metal-less elongated tube). This problem is solved by setting compensators - the coupling parts in the form of loops. The property of polypropylene and metalloplastika elongate must necessarily be taken into account in the design.
- Compounds unsplit pipe segments. This often creates problems in need of repair.
- Combustibility. In case of fire after the burning of the pipe around the standpipe creates a strong pull. Fire can very quickly cover the entire house. Therefore, in places of transition through the overlap on the tube set fire couplings.
- When an instantaneous release of pressure results from the sudden stop of water flow (water hammer) stratified pipe. This is the reason for the connection to a centralized hot water supply system is recommended to use metal tubes.
- From metallopolimernyh and PP pipe can not be mounted fire water system.
Do not install a tube of polypropylene and metal and plastic on the outside. Polypropylene is unstable with respect to ultraviolet, and Metallpolimers may burst when freezing.
differences
The main differences between the metal-polymeric and polypropylene pipes:
- Method compound of pipeline components.
- Cost.
- Application.
Mounting
Manufacturers do not recommend to stick to polypropylene tubes. This can only be heated to a temperature at which the strength of the walls is reduced. They are sold whips to 4 m and cut into segments of desired length. pipe parts connected by means of special fittings, elbows, tees, sleeves, also made of polypropylene.
There are two mounting technology of polypropylene pipes:
- Brazing (welding) special welder (soldering for plastic pipes). The length of the tube and the fitting is heated prior to melting and pressed into each other. Cooling down the polypropylene again solidifies, creates a permanent connection. Installation only seems simple, but the lack of experience is impossible to achieve perfect quality joints. High risk of overexposing soldering or vice versa subcooled joint. Therefore polypropylene tubes are not recommended: a concrete floor; underground; inside the walls (concealed installation).
- Cold welding (only when installing the cold water pipe system). To connect pipes with this method is used a special aggressive adhesive.
Releasable connections for polypropylene pipes (for valves and faucets) is prepared using special fittings to transfer to an external or internal thread. Their lack of - large, sometimes inconvenient fact that they occupy a lot of space.
Metal-pipe bend relatively easily. They are sold in coils (coils) with a length of 50 - 200 m. To assemble the pipe of metal is used and a special collet crimping fittings. Sales have corner fittings, but they are not necessary because of the flexibility of the tubes. For mounting need simple tools - press pliers for plug spanner for permanent connections.
By setting plastic pipes complexity significantly outperform polypropylene.
application
To install the ventilation system or sewer polypropylene tubes are suitable, but no metal and plastic.
PP pipe not recommended contour for mounting underfloor heating systems. There are several reasons:
- low thermal conductivity - for heating will need more energy costs;
- elements of the heating surface, are usually laid in loops - PP tubes have cut and welded under right angle, a high risk of getting unreliable joints under a concrete screed solve the problem of leakage is it is impossible;
- under the screed set-loop compensators are needed to resolve the problems associated with the extension tubes, it is also impossible.
The only advantage of using pipes made of PP - cheap. Metal and plastic pipes on the contrary - one of the best options for installation of the system "warm floor". It is only necessary to choose high-quality products from a reliable manufacturer, is not subject to delamination. To avoid mistakes, you can buy a small piece of the tube and warm to 100 ° C.
Price
Running meter polypropylene tube costs about three times cheaper than metal-plastic. Win lines PP and installation costs. The price of installation works - from 150 to 500 rubles / rm. m. Installation of metal and plastic costs from 500 rubles / pog.m.
