Due to growing population figures in cities, the demand for water is constantly on the rise in urban areas. To meet this higher demand, water utility companies must retrofit large diameter transport lines in densely populated inner-city areas, which often poses major challenges. Trenchless installation techniques combined with Ultrasonic NonDestructive Testing (NDT) offers minimised utility risks at reduced construction costs. Belgium is one of the countries in the world with a serious lack of drinking water supply. There are no mountains or snow and a limited number of large rivers as well as a high population density.
To meet increasing water demand in the coming years, FARYS, the water utility company of Flanders, Belgium, decided to install a 1.5 km, 500 mm diameter HDPE water transport line in the inner city of Saint-Niklaas. To minimise disturbance to the residents, keep the infrastructure intact, and ease the installation of the new pipe, which has an expected operating pressure of 16 bar, a 750 m route was necessary 23 m beneath the existing pipeline.
The route had many obstacles, such as a high-rise building, a parking lot, a shopping mall, and residential housing. Considering the high pulling forces required for the horizontal directional drilling (HDD) trenchless technique used, FARYS technicians wanted extra reassurance that the pipe being pulled into the ground would be 100% tested and perfectly welded. Polyethylene (PE) joints are completely reliable and tested for HDD, but how could they minimise the potential risk of any subsequent damage?
Ultrasonic NDT was the perfect solution. For large diameters FARYS formerly relied on steel or ductile cast iron (DCI) pipes, but the rigidity and missing end-load resistance of metal pipes meant they were not a valid option for the project, as there were horizontal curves in combination with the vertical ones to be handled. In comparison, the flexible, fully restrained, homogenously welded PE pipes with a corrosion-free lifespan of more than 100 years convinced the decision makers that this was the right choice.
Only high-quality suppliers were selected for this project to ensure the best possible performance and reduce the risk of leaks. With its great technical reputation, GF Piping Systems was chosen as the provider of the fittings and jointing technology with its highly cost-effective solution. The company is a leading flow solutions provider worldwide, enabling the safe and sustainable transport of fluids. The company specialises in plastic piping systems and system solutions plus services in all project phases. GF Piping Systems has operations in 31 countries, to offer sufficient availability and quick, reliable delivery.
Fit for Service
To minimise possible risks and assure the quality and reliability of the welds, all HDD joints were scanned with the customised ultrasonic sensors and assessed by GF Piping Systems with Ultrasonic NDT. Typically, 20 to 30 welds can be tested per day. “Using the data obtained and our unique algorithm, coupled with our extensive testing and own highest quality standards, we are able to provide a long-term pass or fail statement on the butt fusion weld.” explained Sanjay Patel, GF Piping Systems’ Global Business Development Manager Specialised Solutions. This pass or fail ‘Fit for Service’ weld report is provided after using Ultrasonic NDT.
If passed, GF Piping Systems provides an extended weld warranty. FARYS received its report within 24 hours of testing. With Ultrasonic NDT the project can proceed with assurance thanks to scientific proof that the welds are secure. This solution offers an alternative to current destructive testing practices worldwide. Ultrasonic NDT is part of Condition Analysis, where GF Piping systems offers its customers testing solutions for those installations that are more critical or require more safety in the operation.
Ensuring High Flexibility
The contractor saved a significant amount of valuable installation time thanks to the ease of installation using the perfectly tuned machines and tools for electrofusion of the ELGEF Plus couplers. The couplers are part of GF Piping Systems’ high quality electrofusion system with a modular concept, which ensures high flexibility from 20 mm to 1,200 mm diameter with active reinforcement. FARYS confirmed the hassle-free and fast installation of electrofusion couplers even in big dimensions. For a reliable, economical, and sustainable water distribution it is essential that all piping components like pipes, fittings and valves are connected safely and reliably. GF Piping Systems offers a comprehensive range of jointing technologies.
The ELGEF Plus electrofusion system provides a homogenous connection of materials between pipe and fitting to contribute to a reliable network. This system also includes all necessary tools, machines and training that are necessary for proper installation. The positive outcome of the Ultrasonic NDT tests reassured FARYS that the installation was reliable and leak-proof. Moreover, FARYS invited many colleagues from other water and gas companies to show and share the knowledge gained from this project. Furthermore, as a final cherry on top, the utility company also decreased the network’s carbon footprint with this project, as the production of raw materials, production of pipes as well as the transport and disposal of PE pipes is significantly smaller than it is for metal pipes.
