In 2021, DNV launched the H2Pipe joint industry project (JIP), where the main objective is to develop a Recommended Practice (RP) for offshore hydrogen pipelines which will be a supplement to the DNV submarine pipeline standard DNV-ST-F101. DNV-ST-F101 is a recognized standard for safe and reliable design, construction and operation of offshore pipelines. The RP which has been developed in the H2Pipe JIP, DNV-RP-F123 ‘Hydrogen pipeline systems – supplementary requirements’, is currently on public hearing, and is planned to be published in late 2025. The RP has been developed for offshore hydrogen pipelines designed in accordance with DNV-ST-F101. But in some cases, the RP can be relevant to onshore pipelines given that there are no conflicts between local regulatory requirements.
The potential for hydrogen embrittlement and the risk of adverse effects on the integrity of carbon manganese pipelines is widely recognized. The actual effects of hydrogen and its blends on the mechanical properties of these materials, however, are less well understood. Pending further research results and evidence in relation to these mechanisms, the first version of DNV-RP-F123 is considered an initial step towards highlighting the aspects that require special attention, during the design and re-qualification of pipelines, for the transport of hydrogen.
The objective of this paper is to present the key recommendations in DNV-RP-F123 for the design, construction, re-qualification and operation of hydrogen pipelines. The presentation will cover safety aspects for transportation of hydrogen gas in pipelines, concept development and design premise, materials and pipeline design, construction, operation and re-qualification. The paper will also highlight key uncertainties and challenges that require further attention and research in order to arrive at more robust and optimized design solutions of hydrogen pipeline systems.