Especially for central heating and under floor heating, the Interplast manufactures linked polyethylene pipe with oxygen barrier.
The Como-pex Oxygen Barrier pipe consists of 3 layers:
- Inner layer linked polyethylene..
- Binder layer for better adhesion of the EVOC with the main pipe.
- oxygen barrier layer (EVOH-ethylene vinyl alcohol polymer)
Additional properties from those of ordinary pipe Pex, are discussed below:
- The specific oxygen barrier prevents oxygen and other gases to penetrate through the tube, the closed circuit heating and corrode metal parts of the system (e.g., radiators, boilers, valves). In the case of under floor heating, where the circuits are long lengths such use is considered essential.
- Have higher mechanical strength than the ordinary pipe Pex, because two additional 0,15mm thick layers are additive material. For example, the usual Pex pipe must have a minimum outside diameter of 16mm and a minimum wall thickness 2,00mm to cover the DIN 16892. The pipe with oxygen barrier must have a minimum outside diameter of 16,3mm and 2,15mm minimum wall thickness to meet the DIN 16892 (mechanical strength) and DIN 4726 (defining the oxygen permeability).
- They have smaller linear expansion. In laboratory tests, Como-pex pipe samples at 120ºC show shrinkage of 0.8% (limit according to DIN 3%). The pipes Como-pex with Oxygen Barrier exhibit shrinkage of 0.5%.