When all attempts had failed to survey a 4.3km GRP desalination plant outlet pipe which was owned by KAUST in Jeddah, Saudi Arabia, The Water Services Group were approached by Co-Mender, a Canadian based specialised engineering consultancy to carry out the survey.
The scope was to determine the cause of an underperforming 1225mm diameter pipes by utilising HD-CCTV and Profiling Sonar to carry out an internal inspection.
To achieve this, we deployed a long-range Pipe Inspection Vehicle (LR-PIV) with a 5000m fibre optic cable, but the survey was cut-short from the desalination plant access hatch at 1275m when we encountered an impassable blockage of sand & debris that reduced the pipe cross section by circa 70%.
The contingency plan to proceed with the survey from the seaward end was implemented:
The survey team, the LR-PIV and the survey equipment was set-up on a vessel which was moved to location and anchored on a multi-point mooring for vessel stability during the survey. Divers removed a grill to gain access into the outlet tower and then placed the LR-PIV into the mouth of the pipe.
Despite a dog-leg bend, a sweeping 45deg bend and a slow outward flow created by a leaking valve we successfully surveyed for 2500m.
The survey enabled Kaust and Co-Mender to determine both the condition of the pipe and the cause of the underperformance.
We have subsequently proposed a pipe cleaning option.