REVEL PIPES

The REVEL-PEX system utilizes pipes on the basis of cross-linked polyethylene, whose production is based on the technology of hydrolytic (silane) cross-linking designated as PE-Xb according to standards. This technology allows economical production of high-quality pipes or composite ones with the aluminium insert complying with the particular technical standards. This technology enables optimal stabilization of pipes against various impacts, such as chlorine resistance, UV-radiation resistance, copper ions resistance and the like and has become the point of interest of all world major manufacturers of pipes. The REVEL company is probably the only manufacturer in the world performing output check of the whole production on the basis of a one-hour pressure test at 0.9 MPa using water at a temperature of 85°C, which exceeds the frame of tests prescribed by the standard. The assortment of PEX pipes is produced in mean pressure line (older designation PN16), whose designing according various standards is well-arranged in chart “C”, composite pipes, also called metal-plastic pipes (MP) are produced in pressure class 1. Apart from PEX pipes 32×3.6 and 50×5.6, which are supplied also in four-meter sticks, the whole assortment of all-plastic pipes is also produced with an EVOH oxygen barrier. The company utilizes a unified colour coding of all-plastic pipes; that is in orange colour. Metal-plastic pipes are because of utilization for surface piping designed in white. Rolls are subsequently wrapped into a plastic foil and provided with the outgoing check label. The assembly company shall check the pipes for transport-related damage after delivery.

The cross-linked polyethylene is a plastic of totally unique properties making the material ideal for production of pipes able to resist long-term temperature loads of up to 95°C (short-term temperature loads of 110°C but only water, not steam). The term “polyethylene cross-linkage” represents a chemical reaction changing the structure and thus also properties of the material. The cross-linkage restricts free movement of molecules, which are arranged into invisible spatial network. The fusible material – thermoplastic – is transformed into infusible material through the cross-linkage (so called thermoelast). This material softens at higher temperatures, however, at the same time it keeps sufficient strength. The spatial network prevents slow creep of the material. In contrast to other plastics the strength of PE-Xb is practically not reduced with time. The strength isotherms of PE-Xb are linear without the breakpoint (sudden decrease of strength) typical of fusible thermoplastic materials. This ability together with a high thermo-oxidative resistance is the essential prerequisite for long lifetime and operational reliability of PE-X pipes. The cross-linkage also increases chemical resistance of the material. Therefore this material is able to resist well the long-term effects of antifreeze and anticorrosive ingredients. Unlike polypropylene it shows long-term resistance to chlorine water in addition. The structure of this polymer efficiently prevents expansion of random cracks. PE‑Xb remains flexible and rigid at temperatures well below the freezing point, where other plastics become brittle. Cross-linked polyethylene is the only material showing the property called “the shape memory”, which can be used advantageously when connecting pipes. These exceptional properties lead to the fact that cross-linked polyethylene has become the most widely used plastic for installations in industrially developed countries. The pipes shall be stored and installed to avoid long-term exposure to direct sunlight. The pipe rolls may be stored in horizontal position in layers of max 8 rolls by reason of potential shape distortion, in which case it is subsequently not possible to slide the expander into the pipe. Operating conditions of pipes made of PE-Xb for the lifetime of 50 years are, in a rather complex manner, specified in standard. Briefly it can be said that any decrease of medium temperature or internal overpressure in the pipe significantly extends the lifetime of pipe. Under normal conditions the lifetime exceeds 100 years. The system based on all-plastic PEX pipes is designed for direct laying into concrete. Because of its thermo-elasticity the pipe behaves like a large compensator of length changes, widening and narrowing its wall without impacting its strength or lifetime. (Built-in copper distributions are subjected to a risk connected with their own length temperature fluctuation, physical movements of building structures and electro-chemical effects and show significantly higher temperature losses than PEX.) Piping made of cross-linked polyethylene need not to be laid into protective hoses over the whole length (on the contrary, they are prescribed for dilatation joints of building structures). The decision on whether to use the covers or not are related to the designer’s decision on inclusion (e.g. in case of distributions on the perimeter of masonry) or minimization of temperature losses of the distributions themselves (e.g. in case of accumulation of distributions under the floor in central rooms). Composite metal-plastic pipes are used in surface piping, sanitary installations or shaped connection of radiators from the wall. Unlike all-plastic pipes, their main advantage is just shape stability and minimum length extensibility fixed by inner aluminium insert. Thus, MP pipes are delivered also in 4m sticks or you can use mobile levelling machine directly in the place of construction. If utilisation of metal-plastic in constructions is considered, their placing in protectors or insulating files is necessary (except low-temperature floor and wall heating).