GRP pipe liners have been established in the wastewater sector for decades. For some years now, they have also been increasingly used for pressure applications for trenchless rehabilitation of drinking water and gas pipes. Continuous maintenance is particularly important for these pipes in order to avoid high economic losses due to water losses or sources of danger due to gas leaks. In the rehabilitation of pressure pipes, GRP pipe liners must meet requirements that extend far beyond the gravity sewer sector. They must withstand a nominal pressure of up to 16 bar in the long term and receive special approvals depending on the country.
Trenchless advantages for pressure pipes
Trenchless pipe rehabilitation has numerous advantages over the open cut trench method. This includes a quick and economical rehabilitation of the old pipe with minimal earthworks and traffic disruption. In addition, trenchless technology protects the environment because it causes less dirt, noise and odour. Compared to the open cut trench method, a total of up to 70% CO2 can be saved. In order to make these advantages available for the pressure sector as well, SAERTEX multiCom® has further developed its SAERTEX-LINER® and brought new liner designs to market maturity that can withstand the high demands over the long term. Therefore, all materials of the GRP pipe liners are adapted to the approvals and meet the technical and, if necessary, hygienic criteria. Both glass fibre fabrics and resin systems were further developed for the new applications and tested for their quality.
The resulting liner designs enable installation companies tomrehabilitate pressure pipelines for wastewater, drinking water and gas using the trenchless installation techniques established on the market.
Worldwide technology drinking water
In Dresden, Valencia and Shanghai, with 100 projects and more than 350 installations, network operators worldwide now rely on SAERTEX multiCom products for the rehabilitation of potable water pipes. In Valencia, Spain, for example, the successful installation of SAERTEX LINERs H2O in late summer 2020 ensured the supply of potable water to over 1.6 million people.
The trenchless pipe rehabilitation of the 500 m pressure line is thus the largest project of this kind on the Iberian Peninsula to date. The measurement was necessary due to the urgently needed rehabilitation of the existing DN 600 cast iron pipe. The network operator EMIMET stated that the main criteria for the upcoming rehabilitation work were: cost-effectiveness, sustainable rehabilitation with a technical service life of 50 years, marginal road and ground work, and maximum project safety. The project was thereupon awarded to GRUPO CANALIS, a Spanish company specialising in trenchless rehabilitation, in combination with the SAERTEX-LINER® H2O from SAERTEX multiCom. With the calculation for the statics, on-site inspections of the rehabilitation section, training of the installation team, and support during the installation, the experts of SAERTEX multiCom accompanied all phases of the construction project. Thanks to the close cooperation between
all the project participants, the entire renovation project (divided into a total of five sections with lengths between 58 and 128 m) was successfully completed within just 14 days.
First gas pipeline with lateral inflows rehabilitated
After the SAERTEX-LINER® GAS received WRc approval, the first gas pipeline with lateral inflows was rehabilitated in spring 2022 in an industrial area in the county of Essex, UK.
The rehabilitation of a cast-iron gas pipeline (DN203 and DN305) located there became necessary due to pitting inside. The trenchless pipeline rehabilitation of the total 1,303 m long pressure pipe is the largest construction project of this kind to date and the first project with lateral inflows. For the rehabilitation, the project participants divided the rehabilitation section into 13 sections with lengths between 52 and 175 m. With the calculation of the statics, the inspection of the rehabilitation route, the training of the installation team and the support during the installation, the experts from SAERTEX multiCom accompanied all phases of the construction project.
