BIP on fire models in structures

The transition toward sustainable mobility with battery electric vehicles (BEVs) and hydrogen fuel cell vehicles (FCEVs) introduces new fire safety challenges in tunnels. This study examines the behaviour of these technologies under critical conditions and their implications for tunnel risk management. Experimental investigations at the Polytechnic of Turin analysed lithium-ion cells (INR18650 M29 and INR21700-50E, both NMC-based) subjected to mechanical, thermal, and electrical abuse. Nail penetration tests revealed thermal runaway events with peak temperatures between 6003750 °C and pressure stabilisation within minutes, while overheating experiments demonstrated temporary stabilisation by safety valve activation before escalation. External short-circuit tests did not trigger runaway, but significant energy release was observed. Gas analysis indicated hazardous emissions, including HF, CO, and CO¢, with concentrations rising alongside initial temperature, confirming the toxicity of BEV fires in confined spaces. Fire suppression is further complicated by prolonged burning, high water demand, and rapid smoke accumulation. For hydrogen vehicles, the study highlights risks associated with compressed storage (up to 1000 bar), including jet flames, tank ruptures, vapour cloud explosions, and BLEVE events. Safety devices such as thermally activated pressure relief devices (TPRDs) mitigate catastrophic rupture but result in full tank venting, producing intense flames. Event-tree analyses show that even minor leaks can escalate into largescale incidents in confined environments. Current tunnel regulations, designed around conventional vehicles, inadequately address these hazards. The findings stress the urgency of adapting ventilation strategies, detection systems, and suppression technologies, as well as integrating probabilistic risk models that capture thermal runaway dynamics and hydrogen release behaviour. This technical evidence provides a foundation for revising international safety standards and ensuring resilient tunnel infrastructure in the era of alternative propulsion.

Keywords

Blended Intensive Programme BIP Tunnel safety Battery electric vehicles Thermal runaway Hydrogen vehicles Fire suppression

URI

http://hdl.handle.net/10400.22/31199

Citation

Fonseca, E.M.M., Campos, A.J.V., & Rego, R.F.N.A., (Eds.). (2025). BIP on Fire Models in Structures [V 1.0]. ISEP. http://hdl.handle.net/10400.22/31199

Publisher

ISEP

Collections

ISEP – DEM – Livro, parte de livro, ou capítulo de livro

CC License

Without CC licence

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