Unkel: Further development for trenchless pipe rehabilitation

SWIETELSKY-FABER uses SPR® RO winding pipe technology for the first time in Germany

Source: Swietelsky-Faber GmbH & SEKISUI SPR
Author: Alexander Thieme, site manager, Swietelsky-Faber GmbH, Leipzig branch

Expansion of the rehabilitation portfolio for large nominal diameters

With the first use of the SPR® RO wound pipe technology developed by SEKISUI with the ROTALOC® wound pipe system from RIB LOC®, SWIETELSKY-FABER is expanding its service spectrum in trenchless pipe rehabilitation. In a current rehabilitation project in Unkel, the process is being used for the first time by the team of the Leipzig branch for the nominal diameters DN 800 and DN 900.

Technological further development includes, in particular, an increase in the efficiency of the equipment technology. This includes the use of an advanced, lighter, and more installation-friendly hydraulic machine, which simplifies the installation process, improves handling on the construction site, and thus contributes to an even more economical execution of the repair work.

On behalf of the Verbandsgemeinde Unkel, located in northern Rhineland-Palatinate, an existing concrete sewer was rehabilitated over a total length of 610 meters. The Verbandsgemeinde Unkel comprises the town of Unkel as well as various surrounding local municipalities and, through its wastewater utility, is responsible for the municipal wastewater disposal of the area. This also includes the step-by-step restoration of the sewer network. The publicly tendered construction project comprised a total of nine sections, of which 160 meters were in DN 800 and 450 meters in DN 900. In addition, 82 laterals were fitted with class B connection fittings in accordance with ISO 11300. The profiles were installed via nine tangential shafts.

The successful implementation of this project marks an important step in the further development of SWIETELSKY-FABER's technology portfolio and creates additional opportunities for the rehabilitation of larger circular profiles.

Winding pipe technology for demanding boundary conditions

The SPR® RO technology was specially developed for trenchless rehabilitation of large pipe dimensions and is suitable for nominal diameters from DN 800 to DN 1800. The process is based on a factory-produced plastic profile that is continuously wound directly in the existing pipe into a new close-fit pipe system. Another advantage of SPR® RO technology is that, compared with conventional liner installation, significantly less equipment technology is required for liner installation, which considerably reduces the necessary space requirement and energy input.

In the project in Unkel, the profile SPR® RO 91-21 RO was used, which was developed in international cooperation between Japan, Australia, and Germany.

During installation, the profile edges are interlocked with one another in a form-fitting manner. This winding process creates a precisely fitting close-fit liner that adapts optimally to the existing pipe geometry. As in any conventional liner installation, transition areas to the structures and profile joints are also permanently created here with EP application or by GFRP lamination.

The result is a dense and durable liner that meets the requirements for long-term and sustainable pipe rehabilitation.

The concrete sewer to be rehabilitated showed various types of damage, including leaks, cracks, leaking socket joints, and signs of corrosion. By installing the SPR® RO spiral wound pipe system, the existing sewer structure was sustainably strengthened and long-term operational reliability was established.

Mortar-free solution with structural and ecological advantages

A key advantage of SPR® RO technology lies in its mortar-free construction. In contrast to conventional rehabilitation methods, especially in the large-profile segment, no annular gap mortar is required for backfilling. This deliberately avoids the use of mortars and cement-bound building materials, the production of which is associated with a significant CO₂ output and is therefore increasingly viewed critically in the construction industry. By eliminating these building materials, installation times can be optimized, additional work steps reduced, and ecological impacts lessened.

At the same time, the process enables the economical and resource-efficient rehabilitation of large pipe dimensions while maintaining high structural serviceability. In addition, the annular-gap-free design enables optimization of the hydraulic properties of the sewer. In particular, in demanding installation situations and with limited accessibility, the technology offers a high-performance alternative to conventional rehabilitation methods.

The overall implementation of the project in Unkel was completed within a record construction period of three weeks.

Extension of the existing SPR® system family

With the introduction of SPR® RO, SWIETELSKY-FABER is consistently further expanding its expertise in the field of wound pipe technologies. In addition to the already established SPR® EX and SPR® TM processes, clients are thus provided with another future-proof solution for the hydraulic, structural and economic rehabilitation of large pipe diameters.

By expanding the portfolio, it will be possible in future to respond even more specifically to the respective requirements of the projects and to select the technically and economically optimal renovation solution.

Successful premiere by the Leipzig team

The first deployment in Unkel impressively shows how willingness to innovate, technical expertise, and committed teamwork work together successfully. The team from the Leipzig branch implemented the new technology with a high level of professionalism, thereby creating the basis for further applications of this process within SWIETELSKY-FABER.

With the successful project in Unkel, another milestone has been reached on the path to innovative and sustainable solutions in trenchless pipe rehabilitation.

Spiral Wound Pipe Day 2027

Anyone who would like to learn about spiral wound pipe technology and experience its practical use live will have the opportunity to do so at Spiral Wound Pipe Day on June 10, 2027, in the Rheingoldhalle Mainz. Under the motto “Experience spiral wound pipe technology live, exchange experiences, and discover something new,” the event offers space for practical insights, sharing experiences, and professional perspectives. The organizer is the Technische Akademie Hannover e. V. (TAH).