The RP extends DNV’s submarine pipeline standard to address hydrogen-specific integrity risks, including embrittlement.

Based on a five-year joint industry project combining research, testing, and operator experience, DNV said RP is intended to be used directly in engineering projects and qualification work.

The document is expected to support early-stage engineering and qualification work for planned hydrogen corridors, where uncertainty around material performance has slowed design decisions.

Several proposed hydrogen corridors linking Southern Europe and North Africa with industrial demand centres in Northwest Europe are expected to include subsea sections.

However, DNV said projects had faced uncertainty around material behaviour, design limits, and operational requirements.

DNV’s Regional Director for Northern Europe, Energy Systems, Prajeev Rasiah, said hydrogen “fundamentally changes” pipeline integrity.

A key challenge is hydrogen embrittlement, where hydrogen atoms diffuse into steel, reducing ductility and increasing the risk of cracking and leakage under pressure.

“[Hydrogen] cannot be treated as a simple variant of natural gas,” Rasiah added.

He said the RP provided an “evidence-based framework” for assessing hydrogen-specific risks in the design, requalification, and operation of pipelines.

However, the assurance player is now launching a third phase of the joint industry project, which will see industry conduct “large-scale testing” to validate data and advance existing standards.

The next phase will include large-scale validation testing, including a full-scale pipeline test at DNV’s UK R&D facility, aimed at verifying material performance and design limits under hydrogen service conditions.

The RP comes as debate continues over the feasibility of repurposing existing gas infrastructure. Environmental Defense Fund has warned that embrittlement, conversion costs and lower operating pressures could limit reuse, underscoring the need for validated engineering standards.

Results from the testing programme are expected to inform updates to the RP and could play a key role in de-risking future offshore hydrogen pipeline investments.