TPi April 2008

Resistance to slow crack growth (SCG) We have seen before that SCG is a key parameter when in comes to lifetime of the pipes; it is now possible to demonstrate that this new material has taken yet another step of at least one decade in the resistance to slow crack growth in the notched pipe test, and also an unprecedented resistance to SCG in all of the tests to which the material has been subjected. Rauprotect II Rausisto The increasing demand for heavy-duty gas, potable water and sewer pipes suitable for the modern and cost-effective trenchless technologies forced pipe manufacturer Rehau to develop a new system solution based on the latest state-of-the-art raw material, Borsafe ™ HE3490-LS-H: the Rauprotect II Rausisto generation was born. The design of the Rauprotect II Rausisto system solution is based on the known stress concentration at the opposite inner surface of the pipe, while external point loads and internal pressure are combined for the whole lifetime of the pipe system. To archive an outstanding crack resistance to meet new market expectations and needs, Rehau used the best available PE100 VRC-Quality Borsafe ™ HE3490-LS-H for the co-extrusion of a thick inside layer of a smooth wall pressure pipe, with overall measures of the established European standards EN 12201 / EN 1555 / EN 13244. This material combination of best PE100+ association- grades for the outside layer with Borsafe ™ HE3490-LS-H on the inside layer brings a cost- effective, technical superior pipe system quality to the market that fulfils market expectations and can be installed with all standard pipe laying techniques, eg butt- fusion welding or jointing with standard-fittings. No expensive special tooling for the removing of outside protection layers is necessary.

▲ Rehau Rauprotect II Rausisto pipes for gas, water and sewage

results against point loads, and can be used without risk for trenchless technologies and in trenches without sand embedding. To improve the traceability of the heavy-duty pipe system, Rehau marks all Rauprotect II Rausisto pipes with durable, laser-marked traceability barcode, according ISO 12176-4 (Code 128, type C) and ISO 13950. Every produced metre of Rauprotect II Rausisto can be easily tracked and welded with modern welding equipment to make pipe laying in the trench easier and safer.

▼ Bimodal Borealis BorStar polymerisation process

The testing institute Dr Hessel Ingenieurtechnik in Roetgen, Germany, approved that the Rauprotect II Rausisto system solution based on Borsafe ™ HE3490-LS-H showed best

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April 2008 Tube Products International