A Modular Hazard Ontology Based on IEC61508

This paper presents HO61508, a modular hazard ontology based on IEC61508. The ontology addresses ambiguities in safety terminology across domains in which IEC61508 is applied, providing a reusable foundation for domainspecific hazard ontologies. To demonstrate its adaptability, a hydrogen-specific ontological extension was developed, H 2 HO, which inherits the modular structure of HO 61508 and is semantically aligned with ISO15916. Both ontologies were evaluated against quality criteria in terms of completeness, clarity, accuracy, and conciseness. The results indicate that the proposed modular approach enhances conceptual precision, supports interoperability across safety standards derived from IEC61508, and provides a formal basis for future standardization efforts in emerging domains.

Keywords: Safety, Functional Safety, Standardization, Ontology, IEC61508, Hydrogen, ISO15916.