Pipeline Integrity Engineers (PIE) who are one of GRAID’s project partners have been working on a pipeline asset condition model. The asset condition model could play a pivotal role in how and where GRAID is deployed for inspection.
PIE was supplied with a sample of data from the 563 AGI’s (Above Ground Installation) on the NTS (National Transmission System) network. This information consisted of construction, operation and current condition data, below is list of some of information that the model takes into account:
- Commissioning date;
- Diameters of the on-site pipework;
- Wall thicknesses of the on-site pipework;
- Site operating pressure;
- Site operating temperature;
- Below ground pipework coating type;
- Efficacy of the cathodic protection system;
- Existence and condition of any pit wall transitions, amongst others.
The output of the model is that it will rank the AGI’s priority for inspection with respect to the risk of external corrosion of the buried pipework. As the AGIs will be constructed of a variety of different pipeline diameters and wall thicknesses, each variant is listed separately so that sections of pipework are categorised correctly.
This information can then be illustrated in a CAD image and the sections of pipework can be colour coded e.g. Green = Pipeline in excellent condition based on direct inspection data and Red = Pipework requires further inspection.
So where does GRAID fit in?
Well firstly the model will be able to highlight sections of the uninspected network, this will then allow for GRAID to be deployed to prioritised sites that require inspection.
Once GRAID has carried out its inspection it will give us two forms of information
- Imagery taken in the form of video from the robotic platform’s on board cameras.
- NDT data taken from GRAIDs on board inspection capability, providing localised wall thickness readings.
The video footage will allow the team to see the condition of the internal pipework.
The wall thickness reading will be compared with the known data firstly to ensure that the wall thicknesses match the information we have which will ensure that the condition model has the correct information so that it can rank the sites correctly. Also if there are any locations showing less wall thickness than we expect the cause of this measured wall loss could be due to external corrosion and then verification works can be carried out to inspect the area further. The information that is recorded will also be inputted into the condition model to allow for periodic inspection.
The first GRAID inspection is due in June and will hopefully provide the PIE team with a great deal of information to allow the model to take shape.