As the hydrogen economy accelerates, large-scale electrolyzers stand at the forefront of sustainable energy production. Yet the inherent hazards of handling hydrogen and oxygen, combined with rapidly increasing capacities, present new and complex safety challenges. Amidst this rise, the industry faces a strategic crossroads: Should these electrolyzers be treated as process units, adhering to the rigorous IEC 61511 process safety standard, or classified as machinery governed by IEC 13849? This fundamental question is compounded by the widespread use of ISO 22734, which, while essential for certification, needs more guidance on which safety paradigm to follow.

This presentation will critically examine the implications of viewing large hydrogen electrolyzers through the lens of process safety versus machine safety. It will explore how the selection of a standard influences system design, risk mitigation strategies, operational safeguards, and maintenance philosophies. Attendees will gain insights into the strengths and limitations of each approach, understand the potential consequences of inconsistent safety classifications, and discover how a harmonized, industry-wide framework could streamline design, improve safety outcomes, and bolster public trust. By shedding light on this regulatory gap, we aim to spark dialogue and drive collaboration toward a more consistent and universally endorsed safety methodology for the future of hydrogen electrolyzer technology.