Restoration of Adduttore Sinni DN3000 – Southern Italy’s largest pipeline

Eight leaks in the largest pipeline of Southern Italy were repaired using AVK’s ingenious Hydro Stop socket encapsulation collars.

In 2017, a plan was underway by the E.I.P.L.I to repair and restore the largest and most important pipeline in Southern Italy: Adduttore Sinni. The DN3000 steel pipeline, which spans across 133 km from the Sinni dam to the western area of the Taranto district, had developed several leaks. At risk were 4.5 million citizens in the Apulia and Lucania regions who relied heavily on its supply of fresh water.

Eight custom Hydro Stop socket encapsulation collars for eight critical leaks

It was essential to carefully plan a repair without restricting water access from this vital water distribution line. While the old joints from the pipeline presented many leaks overall, E.I.P.L.I’s technicians identified eight critical leaks demanding immediate attention. Subsequently tasked with this urgent matter, AVK set out to perform inspections in order to devise detailed solutions for each leak.

Findings concluded that the DN3000 flanges connecting the pipes and expansion joints had worn out, resulting in severe leakages. As such a large population would be impacted by the disruption of this water supply, the only possible means in carrying out its repair was to use our Hydro Stop socket encapsulation collar.

Our team designed eight different variants of Hydro Stop collars for each of the eight critical leaks. These were not only capable of working as encapsulation and repair collars, but also as expansion joints – we delivered a product which fulfilled two different purposes.

Overcoming challenging conditions for a successful operation

Exactly one week after our initial inspection of the pipeline, we installed the first Hydro Stop where the most severe leak was situated. Over the next few months, seven more of the custom socket encapsulation collars were manufactured and installed to the remaining seven leaks. The 133 km pipeline had been successfully repaired, bringing back a sense of security while reducing water loss.

‘E.I.P.L.I management were stunned by the flexibility and reliability of our Hydro Stop. To date, these DN3000 collars were the largest socket encapsulating collars ever installed.’

But the installation process did not come without challenges. We were often faced with difficult conditions such as harsh terrains. The most notably challenging installation was accomplished in the Montescaglioso district, where the pipeline crossed hillside. This unique circumstance brought about increased pressure from an average of 10 to 16 bar, up to a peak of 24 bar – an immensely high pressure for a pipeline of this scale! Combating this leak was nothing short of a significant challenge. To overcome it, we oversized the collar to ensure its maximum reliability over time.

Hydro Stop encapsulation collars

The Hydro Stop socket encapsulation collar is a universal repair collar designed to encapsulate and seal leakage on the sleeve of a pipe as well as leaking or displaced spigot/socket joints while the pipeline is under pressure. The shaped carter can accommodate any kind of pipe socket including joints connecting two pipes of different materials, flange connections on steel pipes as well as remnants of previous repairs. The collar features up to 40 mm pipe OD tolerance, and is a safe solution even when the pipe OD has not been correctly detected, and in case of oval and damaged pipes. It is available in DN250-3000.