Also produced multilayer metal-pipe. The first (inner) layer – it polibuten high flexibility; second – oxygen-barrier aluminum foil, and the third, giving the construction of tube high strength and fracture toughness, is made of polyester fibers, and covers all the top protective plastic sheath «Nioxy» (Austria) and «Universa» (Slovakia).
Recently, the markets began to appear metal-pipe with the base of copper.
Also listed are available as composite pipe of three layers of polypropylene – between two layers of ground is a layer of a special fiber of less ductile PP. Using a special fiber composition in polypropylene tubes can significantly reduce the linear expansion compared with conventional polypropylene pipes with a decrease in pipe wall thickness. This achieves a higher bandwidth.
Comparative characteristics of pipes made of certain materials are given in Table 9.
Table. Comparative characteristics of pipes made of different materials
| Options | Steel | Copper | PEX | Polyvinyl chloride (PVC) | PEX-b | Repoussage |
| Внешний вид Appearance | Satis- The measuring; used zinc, with desirable follow color |
Oxide black; need application cover |
Neat; not require application cover |
Neat; not need in deposition cover |
Neat; not need in deposition cover |
Neat; not need in deposition cover |
| Corrosion resistance | Average, corrode humid Environment |
Good, corroded by ingestion in the system, green divorce with leakage |
Do not corrode | Not corrode | Not corrode | Not corrode |
| Density | Greatest | Much | Low (light) | Low (light) | Low (light) | Average |
| Thermal conductivity | High | High | Low | Low | Low | Average |
| Hardness | High | Enough high | Low | Low | Low | Low |
| Rigidity | Hard | Hard | Enough Hard | Enough Hard | Enough Hard | Permit significant bend |
| The coefficient of thermal expansion | Small; thermocapillary mpensatory needed |
Small; thermo-joints not needed |
Significant; with a length more 5 m needed thermo-joints |
Significant; at length 5 m necessary thermo-joints |
Significant; at length 5 m necessary thermo-joints |
Minor; термо-Joints not needed |
| Method of assembly | Mechanical steel fittings |
Soldering with solder containing Toxic Lead | Welding softening | Glue | Welding размягчением softening |
Mechanical stainless fittings |
| Speed Mounting one connection | Not faster 5 min at room temperature | Not faster than 1.5 minutes at a temperature to 500 ° C | Not faster 30 s at temperature 160 ° C |
Not faster 2h at room temperature | Not faster 15 s at температуре temperature 160 °С |
Not faster1.5 min at room temperature |
To not buy a pig in a poke “, it is necessary to study edge slice. Interior and exterior walls shall be coaxial, and the pipe itself – to have a perfectly round shape. Is not allowed roughness or excrescences. Another sure sign of trash, if polypropylene and polibutenovye pipes connected to the fittings, even in cold condition. They must enter into each other and the welding machine with a force and only in the form of hot!
At tubes and sleeves for drinking water, must be an icon indicating the admission of these elements to drinking water in the producing country.