Hazard and risk evaluation in hydrogen pipelines

Purpose - The purpose of this paper is the definition and the implementation of a simplified mathematical model to estimate the hazard and the risk related to the use of high-pressurized hydrogen pipeline. Design/methodology/approach - This study aims to investigate the effects of different hydrogen operations conditions and to tackle with different release or failure scenarios. Based on the combination of empirical relations and analytical models, this paper sets the basis for suitable models for consequence analysis in terms of estimating fire length and of predicting its thermal radiation. The results are compared either with experimental data available in the literature, thus by setting the same operations and failure conditions, or with other conventional gaseous fuel currently used. Findings - The findings show that the release rate increasingly varies according to the supply pressure. Regarding the effect of the hole diameter, it hugely affects the amount of hydrogen escaping from the leak, up to a value of approximately 0.3 m, after which the release rate remains fixed at a maximum of 43 Kg/s. For failure consequences related to jet flame, the leak dimension has a strength impact on the flame length. Originality/value - This paper represents a helpful engineering tool, to establish the safety requirements that are related to define adequate safety buffer zones for the hydrogen pipeline in order to ensure safety to people, as well the environment.