Over the past month, we have been focusing our attention onto the current Non-Destructive Testing (NDT) system we have installed onto GRAID. The two Electro-Magnetic (EMAT) sensors we have currently installed take individual localised through wall thickness measurements. As a project, we acknowledged we did not fully understand the full capability of the 1st generation of the EMAT NDT sensor.
We found ourselves in a position where we had two options, the first was to deliver a third trial site and potentially not find any defects or alternatively, we could carry out an enhanced NDT works package. By doing this we could utilise defect spools that are available from the National Grid’s Gas Transmission academy at Eakring, which would further our knowledge in how the sensor arrangement behave to different damage types.
The project management team agreed that carrying out an enhanced NDT works package would further our knowledge and understanding of the sensor arrangement as we knew that based on the success of the live trial at Pannal offtake we knew that the robot could be effectively launched and recovered from the system.
Once agreed the project team developed a works package which would allow us to separate the sensors away from the robotic platform, and then take measurements from several defect spools we have available which included machined defects, general corrosion, pitting corrosion, dents and dent plus gouges. To give us a relative comparison we also carried out traditional UT on each of the spools so that we could compare the two readings.
All the readings have been taken from the spools and the data has now been passed onto to our project partners Pipeline Integrity Engineers (PIE) for further analysis. Initial findings appear to be promising but once the final report has been published we will share the information in a further publication.