Close-Fit Lining in Hötensleben: Esders Pipeline Service Rehabilitates Main Water Pipeline

During the rehabilitation of the main water pipe in Hötensleben, the local water supplier and wastewater disposal company TAV Börde faced major challenges. Due to the demanding route and narrow access roads, the egeplast ege-Liner® was used in Close-Fit-Lining – an efficient and environmentally friendly solution.

Environmentally Compatible Method

Already during the necessary preparatory work for the rehabilitation project in Hötensleben, near the former inner-German border, the commissioned Esders Pipeline Service GmbH had to overcome particular challenges in September 2022. For instance, a filter gravel packing had detached from a pumping system, leading to increased deposits in the old pipeline, which had to be removed with the aid of a high-pressure cleaning system.

Existing bends, reductions, and various old pipe materials such as cast iron, steel, PVC, and asbestos cement pipes complicated the rehabilitation measure. Furthermore, the route profile posed additional challenges, as it largely ran across agricultural areas and, in some sections, through residential areas. Finally, restricted access roads and significantly reduced traffic spaces in certain sections of the rehabilitation route further complicated the project’s implementation.

Therefore, when selecting the rehabilitation method, the soil-friendly and ecologically compatible PERelining without annular space (Close-Fit Lining) according to DVGW Worksheet GW 320-2 was chosen. With this deformation process, excavation pits only need to be dug at specific points. Just like resources, fertile soils (such as the humic topsoil layer) are preserved, and the surrounding nature is not unnecessarily burdened.

Effort and Costs Significantly Reduced

After uncovering and cutting out the respective pipe sections in the excavation pits, the existing potable water pressure pipeline was inspected for any obstacles, deposits, contaminations, or damage to the pipeline. Following the high-pressure cleaning, a final calibration of the old pipeline was carried out to pull the new pipe, the egeLiner®, through the starting pit.

The creation of the insertion and target excavation pits, as well as the uncovering of the existing old pipeline, were carried out on behalf of TAV Börde by SPIE Versorgungstechnik GmbH Gommern. The pulling device, usually a capstan winch, pulls the folded egeLiner® from the drum, through the starting excavation pit, into the old pipeline towards the target excavation pit. This demonstrates one of the major advantages of the deformation process compared to the classic pipe string method with annular space. Since the minimum bending radius of the Close-Fit Liner is significantly smaller than that of a normal pipe string lining with annular space, the dimensions of the excavation pits can be reduced. Consequently, the excavation effort, and thus costs and other impairments, are considerably reduced, also because no pipe string needs to be pre-stretched above ground and pre-welded to the section length. The respective section lengths are produced project-specifically at the factory and delivered on drums.

Final Work Steps

The successful installation was followed by a pressure test and disinfection or bacteriological examination as final steps before the renovated pipeline could be put back into operation.

The connection to the existing old pipeline was made on-site in Hötensleben using commercially available PE pipe OD160 SDR17 PN10, with the aid of relining electrofusion couplers DN150/160 and previously inserted stainless steel support sleeves, as the egeLiner® has a slightly smaller outer diameter than the standard pipe.

In total, Esders Pipeline Service rehabilitated approximately 650 m of dilapidated potable water pipeline in Hötensleben.

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egeLiner^®

The pre-shaped egeLiner® is wound onto steel drums, tailored to the length of the section being renovated. This achieves a cross-sectional reduction of up to 40 percent, allowing long construction lengths to be delivered to the site.

Fundamentally, the folded egeLiner® pipe strives to equalize the stresses frozen in its wall and transform back into its round original shape — this is referred to as the reversion process, which causes the return to the original form (“memory effect”). This property makes the close-fit method highly efficient and ensures that, after successful Installation, the egeLiner® adheres closely to the inner wall of the old pipe and can be fully integrated into the existing pipeline network without restriction.