Seeking Unmanned Inspection System for Buried Pipes

Background / Description

The pneumatic waste conveyance system (PWCS) is an automated waste collection system that uses high-speed air (~22m/s) and a vacuum-type underground pipe network to collect household waste from residential blocks, which is then transported through underground pipes to a sealed container. Trucks then periodically collect the waste for disposal.

Pipe thinning/corrosion may occur due to abrasion of fast moving refuse/chemical reactions from the presence of liquid waste. Potential defects that may occur within the pipelines could include uniform/localised abrasion/corrosion.

In order to identify potential mitigation/maintenance strategies, it is necessary to have a system that is able to inspect and monitor the inner surface condition of the pipes, identify and detect potential defect areas, and collect these data for diagnostic purposes, with minimal manual inspection.

For manual inspection of the pipelines, inspectors may face potential hazards such as confined space, shortage of air supply, build-up of undesirable gases and pest infestation. Hence, solutions are sought for inspection to be conducted remotely instead. Flushing of the entire PWCS is done regularly and may be carried out prior to inspection.

Technical Specifications

  • Currently, the typical PWCS has an inner diameter of ~500 mm, and an average system length of ~2km (horizontal refuse transport pipes). Long radius bends with minimum turn radius of 1500 mm for curve segments is required. Pipes are in-placed vertically, horizontally and not more than 90 degrees around bends.
  • Access points of dimensions not less than 600 mm x 600 mm to the pipes are typically located close to the curve segments and can be found at every 50m.
  • During inspection, the PWCS system may be kept out of operation. However, the total inspection time should not exceed 4 hours.
  • The inspection system should be able to inspect the inner surfaces of the 7mm thick unlined and uncoated mild steel (low carbon steel) API 5L Grade B pipes for defects.
  • The sensor system may be based upon either a visual inspection and/or non-visual technique. It is to be noted that only non-destructive examination (NDE) techniques are to be considered.
  • Defects could include pipe thinning (up to 30% of the original thickness), corrosion (uniform, pitting), scratches, abrasion, cracks, deformation, indentations.
  • The sensor system should be able to identify the above defects and be able to collect coordinate data and map the 3-dimentional view and location of defects in the pipelines for diagnostic and data recording purposes.
  • The inspection system may be autonomous or remote controlled, untethered/tethered.
  • Systems should have an extraction method/plan should the system fail in the midst of operation.
  • It is expected that the system may encounter some residual solids and fluids may be present in the pipelines, however these should be minimal with the system flushing.
  • Due to non-direct line-of-sight and multiple path conditions, optimisation of the communication and navigation systems may be necessary
  • It is preferable for the solution to be a complete solution.


The system is envisioned to be able to navigate autonomously with both the capability of detecting and repairing the defects, able to collect coordinate data and map the 3-dimentional view and location of defects in the pipelines for diagnostic and data recording purposes. The problem owner is open to solutions that have the capability to address the problem statement and challenges.

Preferred Business Model

  • R&D Collaboration
  • Others

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