The functioning of a hydrogen economy at an industrial scale requires pipeline transportation. Asset owners around the world are looking at developing such pipeline infrastructure by taking advantage of the existing hydrocarbon assets. Recently, hydrogen transportation has gained traction, and this has necessitated pipeline owners to understand the effects of H₂ on the integrity of their pipeline assets.

The incumbent industry codes do not offer a practical approach to holders of licenses to operate existing pipeline assets for repurposing them safely and economically into hydrogen transportation. At the same time, the enforcement of unnecessary conservatism could penalize the realization and the value of a hydrogen chain economy. The SAFEH2PIPE project funded by Research for Coal and Steel (RFCS) aims to understand the effect of damages in Hydrogen pipelines. As a part of the project, a literature review is conducted to identify the gaps in the current industry codes, guidelines and research work, for maximum utilization of pipelines. 

In this paper, experience, and the latest data on pipeline (material) performance is collected and analyzed, keeping the focus on pipeline material behavior in high-pressure H₂ and blending (H₂-NG mixtures). Engineering gap analysis and review of H₂-related failure mechanics and integrity requirements for a pipeline transporting gaseous H₂ or H₂-NG blends was conducted.

The effect of hydrogen on the pipeline integrity when there is a presence of mechanical damages like dents, gouges, cracks, corrosion, fatigue, and hard spots were reviewed. Material testing procedures (for measuring stress-strain, stress intensity factor, fracture toughness, etc.) were reviewed and the causes of variability in results were analyzed. State-of-the-art report from this literature study showed the level of conservativeness of the standards (like ASME B31.12, AIGA, EIGA etc.) while showing new research data in the literature that helps in better understanding of H₂ effects on pipeline material.