Case Study

Braefoot Bay: AquaClam®

Braefoot Bay, Fife
The Braefoot Bay Marine Terminal is used for offloading liquefied petroleum gas for transportation internationally. Loading is facilitated using the Jetty Loading Platform, a structure supported by 114 marine piles of 30” and 42” Diameter in water depths up to 30m. The structural integrity of the piles requires to be inspected and maintained at regular intervals.
The Challenge

The jetty structure is a live plant with constant vessel movements and loading activities this resulted in very limited access to the piles.

Both the cleaning of the marine growth and inspection of the piles were previously completed using dive teams. Due to the extensive hard and soft marine growth, fast tidal, changing tidal levels and often poor visibility, the environmental challenges for using divers are significant.

Inspection by divers can only facilitate local cleaning and spot UT checks.

The location of the piles directly under the jetty is also a challenging location to access with no obvious access points or available lifting facilities.

Key Summary
  • Provision of the AquaClam® tool and experienced installation and operation team to successfully execute splashzone cleaning and inspection of x 6 30” piles.
  • Over 98% of both hard and soft marine growth up to 75mm thickness was removed.
  • Detailed close-out report containing still images, live footage, corrosion maps, complete WT dataset and the relevant visual and UT reports.
  • Cleaning and inspection scope completed in reduced schedule and cost over previous campaigns.

"Without the AquaCLAM we would have required to use a diving team, which would have brought additional risk and challenges to the project. We were very impressed with the quality and quantity of visual and WT results that were produced by the tool. AquaCLAM enabled us to complete a successful inspection project. "

Offshore Structures Engineer, Shell

The Solution

A representative sample of the 114 marine piles is inspected annually, with 6 x 30” piles being selected for this scope of work.

Inspection comprised visual inspection of the general structure, supported by ultrasonic thickness measurements in three zones, one above, one below and one in the tidal zone.

Each zone required cleaning to remove hard and soft marine growth prior to inspection.

AquaTerra deployed the ACI-030 AquaCLAM® cleaning and inspection tool, capable of inspecting tubulars from 26”-32”.  The tool was installed and operated from a safe location on the jetty with no requirement for diving support.

The tool cleaned and inspected three bands on each pile (air gap, splashzone, subsea) AquaCLAM® facilitated safe and productive cleaning and inspection operations between shipping windows and tooling operations were unaffected by tidal movements or swell.

The tool was operated and cross hauled into position by a single 4 Man team. All lift planning and equipment was provided by AquaTerra.

Before Cleaning
After Cleaning
The Result
Using variable high pressure jetting heads UHP successfully removed soft and hard marine growth without damage to protective coatings.

HD cameras and high-powered lighting allowed continuous visual inspection of the pre and post clean, and also throughout the scanning operations.

AquaCLAM®'s subsea UT scanning equipment provided continuous accurate readings around the entire circumference of the pile, not just at cardinal points as would be the case with divers. The data from each scan was presented in the onboard software which could be viewed in real time by the operator in the control cabin.

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