It is TPL’s policy to continually monitor the integrity of its pipeline network. To this end, an internal inspection tool commonly known as an Intelligent Pig is utilised. The instrument uses the magnetic stray flux principle to determine and record any possible areas of metal loss due to corrosion and/or other phenomenon.
The results of a recent Intelligent Pig survey indicate that the pipeline is generally in a good condition. The pipelines are also cathodically protected against electrolytic corrosion. TPL is acknowledged as one of the leaders in the development of this technology in South Africa.
Monthly helicopter inspections are carried out to ensure that the servitudes are free of encroachments and that no washaways loss of cover over the pipe has occurred.
Concrete markers are installed along the pipeline route to ensure that the precise position of the buried pipe is known and coordinates are captured on the GIS. The registered servitudes generally embrace the right for TPL to lay, maintain and operate the said pipelines. The servitudes are registered against each property title deed. The landowners that were compensated at the time of expropriation generally retain the use of the land for agricultural and other shallow surface and non-permanent structures. This allows for unobstructed access to the pipeline at all times.
TPL is acknowledged as one of the leaders in the development of this technology in South Africa’s harsh stray current corrosion environment.
The external surfaces of the buried metal pipelines need to be protected against electrolytic corrosion which is relatively severe. A DC source is applied between the pipe and sacrificial anode to control the stray currents. There are 116 rectifiers along the pipeline network with approximately 1 800 test points where potential levels are checked twice a year over a 24-hour period.
As the only petroleum products pipeline operator in South Africa, TPL has acquired some unique skills relating to pipes. Hot tapping is one of them. This is a process to re-route or do maintenance on an operational pipeline without disrupting the flow.