PIPA Live Water Pipe Inspection and Leak Detection Large Diameter

Scope of Works

PIPA was recently contacted by a water utility client in Hong Kong. The utility had identified a high risk water main that supplied water to an airport, and was laid under the sea bed. The entry point on the bitumen coated steel pipeline was in a water treatment work area. The client needed a long range tethered solution, to check the pipe for leaks and potential blockages.

Project Challenges

The pipeline is a raw water outlet submarine main and deeply buried under the sea bed.

The pipeline is a 1800mm pipe with 6 to 10 bar pressure, and was installed 35 years ago.

The pipe length was 4.4 km and has several bends.

The client required telemetry to include water temperature, pressure, acoustic leak detection and visual CCTV assessment.

The client discussed using alternative options including the following methods:

*  Noise correlators – no leaks identified (not accurate on large diameter metallic pipes)

*  Free floating devices – Due to the pipe being sited under the sea bed, the client could not risk the system getting stuck or lost within the pipeline

*  Using human divers to visually assess the pipe externally. This would have been time consuming and potentially dangerous

The clients needed to risk assess the asset, and to confirm there were no hidden internal defects or blockages identified.

PIPA uses technology that includes a pressure rated camera and hydrophone capsule called PLUTO™ tethered to a 5000m cable to give the operator video and recorded audio data during an inspection. The system enters a pipeline via a 150mm riser, and is fully chlorinated during its Insertion; the system works on a live basis, with no Interruptions to the clients services, and can cover a distance of up to 5km per day.

How does the system work?

The technology requires a pipe entry point and pipe exit point. Upstream a pressure rated camera is inserted to launch a weightless cable and Hydrochute™, this is all sealed within a pressurised housing. The water flow enables the Hydrochute and cable to travel down the pipeline to the required distance. Downstream an expanding net and camera is inserted into the pipe to stop the Hydrochute travelling any further, and to remove the Hydrochute and cable during live water conditions.

The PLUTO system is attached to a secondary cable, and this is pulled back through the pipeline using a motorised cable drum, pausing every metre to overlay distance meterage on to the final report. All data is captured onto an internal drive, and a detailed date report is supplied for the client thereafter.

Survey results

*  API-PIPA successfully surveyed the entire 4.4km length in a single insertion, an industry first

*  Tethered insertion technology system allowed for precise location of the leaks or defects to be identified, and offered a low risk approach to long range pipe inspection

*  Acoustic system is very sensitive and able to pick up small and large leaks

*  Operator was able to identify other points of interest, air pockets, joint and bend location

*  Pipe telemetry was successfully recorded to supply client with acoustic, pressure and water temperature data


It would have been very difficult and expensive for the utility/contractor to confirm issues within the water main. The CCTV and acoustic capability proved indispensable for locating issues and trouble shooting.

PIPA and API completed the inspection in 1 working day to install the cable, and a nightshift to complete the long range pipe inspection survey.

The contractor resolved the ongoing issue by removing the guess work at a fraction of the cost and time they would have invested in other pipe inspection methods.


PIPA representative said- The project was a great success, Ideal due to pipe location and material and also a great case study for our company. The contractor had exhausted all other pipeline inspection avenues, and was more than relieved when we offered a solution.

The Hong Kong PLUTO project was an industry first, by delivering a 4.4 km pressurised and tethered pipe inspection survey.

PIPA now offers all of its technology to water utility companies all over the World, including remote training and reporting data support.

For more information on PIPA Technology please see our website www.pipa-uk.com


   API Team on Site         Exit Point     Floating Cable

   Extracted Hydrochute     Insertion Point     Pipeline

   Pluto     Pluto System     Retrieval Camera

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