The new main-to-house sewer rehabilitation method by Trelleborg solves some of the – still unsolved – problems in trenchless relining of lateral connection pipes. For the very first time in Germany, the new system was used under real project conditions on a site near the town of Rheinberg in November 2012.
According to the responsible project officer in the Public Works department of the municipality of Rheinberg, the ”Turmstrasse“ sewer rehabilitation project was supposed to have been completed some time ago. In the ”Turmstrasse“ district with its dense neighbourhood of old buildings, the DN 300 concrete
main line showed the typical damage patterns of public combined sewage systems from the 1950ies/1960ies with a lot of improperly connected laterals, longitudinal and crosswise cracks, as well as displaced joints. The DN 150 house laterals serving the homes at a connection angle of 90 degrees were also in urgent need of repair.
The project task was to rehabilitate a sewer length of about 280 metres including approximately 10 lateral pipes with lengths varying between 2.75 and 4.0 metres. The manholes in the main line were intended to be renovated in a second step. The project was tendered out by the authorities and awarded to the bidder offering the best price. Nothing unusual so far.
Hard-to-access inspection holes or openings made it difficult to place the liners for inversion into the lateral pipes. It then became really tricky and cumbersome when two specific laterals offered no access at all, neither inside nor in front of the house, for inserting the DN 150 pipe liner.
This challenging part of the project was taken on by Fleer-Tech GmbH from Lehrte coordinated by Dipl.-Ing. Olaf Stock as the site manager. Fleer-Tech GmbH is a renowned pipe and sewer rehabilitation company. In said two special cases, they decided to rely on the new MtH method developed by Trelleborg Pipe Seals
Duisburg GmbH in order to accomplish what would become the very first MtH application within Germany.
The MtH process
The MtH (main-to-house) method enables the relining of lateral connections from the main line to homes for pipes having nominal diameters of 200 mm or more. The MtH system has already been marketed and used successfully by Trelleborg Pipe Seals Duisburg GmbH in the USA since early 2012. The results prove the system’s effectiveness in renovating lateral pipes from the main line.
The MtH method has now proven its worth in practical application also in Germany and opens up new ways to reline house laterals from the public side without direct contact or interference with the property owner. Good preparations in association with the ease of installation and simple steam cure of the MtH liner allow installers to perform up to 3 lateral lining jobs a working day. The length of the liner to be installed is of limited importance to achieve this performance, and the quality is uniformly high.