FSRU Toscana is a permanently moored Floating Storage Regasification Unit located 22km off the Italian coast between Livorno and Pisa. During planned turret maintenance, its mooring and riser systems were temporarily wet-stored on the seabed before being reinstalled as part of the terminal’s recommissioning.
THREE60 Energy was engaged to verify the integrity of the flexible risers before they returned to service, combining specialist inspection with an efficient approach to annulus testing.
Challenge
Following reinstallation, the client needed assurance over the condition of the riser bore, carcass and end-fitting seal ring, a critical interface providing electrical isolation between the internal carcass and end-fitting.
Baseline annulus testing was also required. The conventional vacuum-testing approach originally planned involved significant equipment and required a hold-back tug to maintain vessel position, adding cost and operational complexity to the recommissioning programme.
Solution
THREE60 initially performed an endoscopic inspection while the riser bores remained accessible, confirming the integrity of the carcass and seal rings before the topside pipework was reconnected.
The team was subsequently asked to undertake the annulus testing using THREE60’s proprietary FlexScout Pro® positive-pressure testing system. Using a compact pressurised nitrogen source rather than conventional vacuum equipment removed the requirement for a hold-back tug and allowed the vessel to rotate freely around its turret during testing.
Result
The inspection successfully confirmed the integrity of the riser seal rings, while the annulus testing provided conclusive results ahead of reactivation.
The approach removed the need for a hold-back tug, reduced operational costs and minimised vessel downtime, helping accelerate the safe recommissioning of FSRU Toscana with minimal disruption to its operations.
