High-pressure pipes made from polyethylene only - A new generation of plastic pipes [PE]

Polyethylene is a thermoplastic material that has very balanced properties and therefore established itself as standard material in piping construction both for the supply of water and also for the low and medium pressure range distribution of gas. However it has not been possible to use the plastic pipeline in the high-pressure range so far because its strength is low in comparison to that of metallic materials. An exception is the fibrereinforced polyethylene pipe RTP (Reinforced Thermoplastic Pipe). Highstrength fibres integrated in the pipe wall allow very high operating pressures. A new approach is to use self-reinforced high pressure pipes, which are known as monocomposites and consist to 100% of polyethylene. The secret of the monocomposite structure is an integrated layer of highly oriented polyethylene tapes. This allows operating pressures twice as high compared to common pre polyethylene pipes. KIWA/Gastec has proven the pressure strength of minimum 40 bars for the “raised pressure” pipe structure which is the doubled strength compared to a standard PE 100 pipe of the same wall thickness. If a higher pressure is required for some special application, the strength of the pipe structure can be reinforced by increasing the ratio of oriented polyethylene in the wall structure. Pressures up to 70 bars have been proven by single pressure tests. As the monocomposite pipes (tradename : HexelOne®) consist just of polyethylene, it can be connected by conventional welding techniques as far as they are suitable for the operating pressure but also mechanical couplers can be used. Ends of the just polyethylene pipe on side and in the factory can be recycled which makes the pipe very environmentalfriendly. Typical applications for the new high pressure PE pipe are those who favour the lightweight, easy weldability, high flexibility and corrosion stability of polyethylene and further need the increased strength for higher operation pressure such as high pressure gas or water pipes, snow machines or industrial applications e. g. onshore pipelines.