Pipeline Operators Forum (POF) White Paper on In-Line Inspection Tool Readiness for Hydrogen Pipelines

Abstract The Pipeline Operators Forum (POF) is a non-profit organization enabling pipeline integrity engineers to share and establish industry best practices to improve the quality of pipeline integrity management at every level. POF set up a working group (WG) on hydrogen pipelines to investigate ILI tool readiness for hydrogen pipeline inspection. This paper summarizes the current perspective of the WG on the state-of-the-art ILI tool readiness level including providing a gap analysis based on joint discussion and feedback of various ILI companies. The WG will rely on the previously published POF standards (for example POF 100 Specifications and requirements for in-line inspection of pipelines) and recommended practices such as for example POF 300 Achieving successful in-line inspection, POF 310 Field verification procedures for ILI, and POF 320 In-line inspection contractor compliance check but recognizing if hydrogen is a new threat. This paper outlines key elements recognized today to be considered for inspection of hydrogen pipelines and possible technology options to address possible issues in terms of threat categories (internal and/or external corrosion, hydrogen embrittlement fatigue, geohazard, third party damage, material properties) and morphology/appearance. In the introduction an overview of ILI technologies and anomaly types considered is given. A proposition for mapping state-of-the-art ILI technologies (axial magnetic flux leakage [MFL], circumferential MFL, ultrasound [UT], resonance UT, liquid coupled UT, electromagnetic acoustic transducer [EMAT], gas coupled Lamb wave, Eddy current, inertial measurement unit [IMU], axis stress measurement, low field MFL) versus pipeline integrity threats is provided by examples. The ILI tool readiness is defined and discussed in detail in terms of key ILI tool component material compatibility. Beside operational safety considerations, options to achieve acceptable inspection data quality are analyzed and elaborated on. The paper concludes by providing a technology gap analysis summarizing required technology development for ILI of hydrogen pipelines. Detailed guidance on how gaps can or should be closed is out of the scope of the paper.