Validation of ILI performance is a critical component of any in-line inspection campaign to ensure that the ILI performance specification has been achieved. This allows high confidence integrity decisions to be made using the ILI data. The issues posed by the energy transition and the introduction of Hydrogen into existing gas networks present acute challenges for the accurate sizing of crack-like features and the subsequent validation of ILI performance in accordance with API 1163. 

This paper discusses the current challenges of validating crack-like defects and the implications of the current industry practice with regards to the requirements of the Hydrogen transition.