Pre-normative research for safety of hydrogen driven vehicles and transport through tunnels and similar confined spaces

It is a long standing finding of the research community that hydrogen behaves very benign in free environment. Confinement and congestion, however, promote more severe accidental consequences. The Network of Excellence (NoE) project HySafe derived from this the strong need for improving the principal understanding of and the development of validated risk assessment tools for the accidental behaviour of hydrogen in tunnels and summarised the state-of-the-art in the HyTunnel study. Facing the intended accelerated deployment of hydrogen powered mobility on one side and the steadily increasing part of traffic infrastructure, which is established in tunnels or in similar confined spaces on the other side, will urge any new standard or regulation for transport systems to address also the specific safety issues involved with this new alternative fuel in tunnels and similarly confined space, like underground parking etc. Serious fires in some road tunnels in the Alpine countries during the years 1999 and 2001 triggered the issuing of the European tunnel safety directive 2004/54/EC . National implementations of this directive are due by 2019. Neither this directive nor any other international regulation, codes or standards, e.g. PIARC 1999 or NFPA 502, provide specific guidance for evaluating the appropriateness of conventional mitigation technology (ventilation, water spray or fog, foams, etc.), conventional safety management and established first responders strategies in case of a tunnel accident with an hydrogen vehicle or hydrogen transport involved. The referred methodologies (FMEA, CFD, etc.) are rather generic and lack validated models for evaluating the effectiveness of the quite expensive tunnel equipment.Therefore, the aforementioned European regulation related to tunnel safety and safe efficient supply of the alternative fuel hydrogen (AFI Directive) and the related safety assessments urgently require a sound scientific basis and a better understanding underpinned by experimentally generated validation data. Obvious knowledge gaps concerning the interaction of hydrogen dispersion and in particular combustion with existing safety installations have to be filled with pre-normative research, relying equally on experimental proofs and numerical extrapolations. The generated knowledge and tools should be translated to similar scenarios, including railway tunnels and underground or multi-storey car parking