Saint Brieuc Agglomeration is a private water utility in the region of Brittany, France, supplying 41,000 customers with water through 1,000 km of pipes.
The vast majority of pipes are ductile iron, and the size ranges in diameter from DN40 to DN600. The pipe age varies from 40 to 125 years, which is not abnormal in France. Over time, wear and tear on the pipes, ground movements, variations in ground temperature, and road works can weaken them, resulting in pipe breakages.
A recent pipe break became apparent when water started to pool on the roadway surface. When there is a leak on a road, it is important to repair it in a short time to allow road traffic to be restored quickly. It is also important to dig as little as possible to limit the damage to the road and reduce the cost of restoration.
It was determined to be a circular breakage which is the most common failure for cast iron pipe, and in this case, the pipe size was DN100. Saint Brieuc Agglomeration has GIS for the entire drinking water network, which gives them all the information they need to do an accurate dig and understand the constraints of intervention and possible obstacles.
The Agglomeration chose the Krausz Repamax® permanent repair coupling from Mueller, in part because it is easy to use, but it is also reliable and durable enough to stand the test of time. This ensures that the city does not have to intervene again a few years later.
Notice was given to the customers that would be affected by the disruption in the water service, 48 hours before work. Once the leak was located, the water was shut off at the main valve near the leak to stop the loss of water and allow a safe repair. Excavators were brought in to dig around the leak and secure the area to meet safety standards to enable the workers to enter for the repair.
A tire shovel was used, as well as a heavy-duty dump truck, and operators had to exercise caution to avoid causing further damage to nearby pipelines or underground infrastructure. Crews secured the work area by using signage to warn road users of work in progress.
It was determined that the breakage was significant enough that the damaged pipe needed to be replaced. The Repamax coupling can be used to repair pipes in the classic way and connect two pipes. This is the advantage of this product, making it suitable for any leak. Two Repamax DN100 of width 280mm with a tolerance range (108mm – 131mm) were used to connect with the new replacement pipe. The lightweight clamping system on the repair coupling meant repair crews could handle it without real support. Also, the radial closing design and sealing systems helped eliminate installation errors.
Before closing the trench, pressure tests were carried out to ensure that the repair was successful and that there were no other leaks. The repair coupling has a hydraulic pressure-assisted gasket that inflates as water pressure increases. This allows for three degrees of dynamic deflection on each end to reduce the risk of damage and cracking due to ground shifts and temperature changes. Once the pressure tests were conclusive, the trench was backfilled with materials and compacted. The road system was restored to its original state by replacing the surface asphalt.
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