Repair of eight leaks on the Adduttore Sinni DN3000 pipeline

In 2017, E.I.P.L.I. planned the repair of several leaks on the largest and most important pipeline in southern Italy: Adduttore Sinni. It is a DN3000 steel pipeline that supplies fresh water to Apulia and Lucania, serving about 4.5 million people. It goes from the Sinni dam to the western area of the Taranto district covering a distance of about 133 km.

Eight critical leaks – eight customised Hydro Stop socket encapsulation collars

There were many leaks on the old joints, so it was essential to plan the repair without causing water stoppage on this important water distribution line. In fact, E.I.P.L.I.’s technicians had identified eight critical leaks on the pipeline that needed particular attention and they asked us to perform inspections on these leaks in order to provide a specific solution for each of them.

Basically, the DN3000 flanges that connected the pipes, as well as the expansion joints, were worn out and had started to leak severely. Considering the large population potentially involved in disruption of water supplies, the only possible way to perform any repair was by using our Hydro Stop socket encapsulation collar.

For the eight big leaks, we designed eight different variants of Hydro Stop collars, capable of working not only as encapsulation and repair collars, but also as expansion joints: we offered a product capable of fulfilling two different purposes. 

Challenging installation conditions 

Seven days after the first inspection of the pipeline, the first Hydro Stop was installed on the location where the most severe leak had been detected. In the following months, seven additional socket encapsulation collars were manufactured and installed on the remaining severe leaks in order to reduce water losses on the 133 km pipeline.

E.I.P.L.I management was stunned by the flexibility and reliability of our Hydro Stop, and to date, these DN3000 collars are the largest socket encapsulating collars ever installed.

Often, we had to face severe conditions during installation. The most challenging installation was performed in the Montescaglioso district, where the pipeline crossed hillside. This special circumstance caused a pressure increase from the average of 10 to 16 bar up to a peak of 24 bar; a very high pressure for such a large pipeline! Stopping this leak was a real challenge, and we therefore decided to oversize the collar to ensure the highest possible reliability over time.