We are producing pipes from polyethylene and polypropylene in an extrusion process, where a profile is wounded around a collapsible steel mandrel. The profile can be solid wall or structured wall. For the production of the pipes we are using Germany based universal production line which allows us to produce thermoplastic pipes with a inside diameter from 300 mm up to 4000 mm. The lenght of the pipes produced is 1-6 meters.

We are producing pipes for the several applications. Main applications are following: drinking water pipelines, pipes for the collectors, sewage, rainwater, cooling water, landfill, outfall pipelines, relining pipelines etc. We can also produce pipes with a special inside layer for the different applications, for example antistatic layer for the ventilation pipes to prevent the accumulation of dust inside the pipeline.
Krah pipes can be produced by the usually known ring stiffness classes SN2, SN4, SN8 and SN16, but also we have the possibility to calculate the ring stiffness by taking account the real situation of the project.  We are using a static calculation program developed by Ing Soft GmbH to make static calculations of underground pipelines and tanks. This makes it possible for us to offer our customer always the best solution.
Krah Pipes DN/ID600 PE pipe ring stiffness value changes over time
The tests are conducted in order to determine the value of the ring stiffness over time. Laboratory tests show constant increase in pipe ring stiffness during the period of six months after production. The test is based on the standard ISO 9969:2008 and has been carried out on a monthly basis in the same conditions and measures were taken from the same exact places. The results may be slightly affected by pre-deformation, as tests have been carried out using the same test piece. Chart shown below shows the increase in the value of ring stiffness from 9 to 10 kN/m², which also shows increasing durability over time of the PE pipes and other bodies produced with Krah technology.