Explosive Characteristics of Hydrogen-Air Mixtures Diluted with an Inert Gas

Mathias Henriksen; Dag Bjerketvedt

doi:10.58895/hysafe.26

Explosive Characteristics of Hydrogen-Air Mixtures Diluted with an Inert Gas

Hydrogen Safety

Volume 2 (2025): Issue 1

By: Mathias Henriksen and Dag Bjerketvedt

Open Access

|Oct 2025

Abstract

Hydrogen is a promising energy carrier and fuel in the maritime sector, which has the potential to reduce the sector’s carbon footprint. Using hydrogen fuel cells to produce electricity on board is becoming increasingly attractive. However, there are several safety concerns associated with hydrogen, including its low minimum ignition energy and wide explosive limits. Inergen is an inert gas that is used for fire mitigation. The system works by reducing the oxygen concentration in the room to approximately 12%, which is sufficient oxygen for humans to avoid fainting or suffocation. Although hydrogen can burn at very low oxygen concentrations, such a system could reduce the probability of ignition and the consequences of an explosion. In this study, we investigated the explosion characteristics of hydrogen mixed with different ratios of air and inert gas in a 20-liter explosion sphere at 300 Kelvin and 100 kPa (absolute). Experimental results for explosive limits, maximum explosive pressure, and the rate of pressure rise during explosion are presented. A simple model to estimate the explosive limit of hydrogen is also presented.

References

Akyuz, E. (2015) ‘Quantification of human error probability towards the gas inerting process on-board crude oil tankers’, Safety Science, 80, pp. 77–86. Available at: 10.1016/j.ssci.2015.07.018
Open DOI Search in Google Scholar Back to article
Cheikhravat, H., Chaumeix, N., Bentaib, A. and Paillard, C.-E. (2012) ‘Flammability limits of hydrogen-air mixtures’, Nuclear Technology, 178(1), pp. 5–16. Available at: 10.13182/NT12-A13543
Open DOI Search in Google Scholar Back to article
European Standard. (2012) Determination of explosion limits of gases and vapours (No. EN 1839).
Search in Google Scholar Back to article
Goodwin, D.G., Moffat, H.K. and Speth, R.L. (2017) Cantera: An object-oriented software toolkit for chemical kinetics, thermodynamics, and transport processes. Available at: 10.5281/zenodo.170284
Open DOI Search in Google Scholar Back to article
Henriksen, M. (2021) A study of premixed combustion of gas vented from failed Li-ion batteries. Doctoral thesis. University of South-Eastern Norway. Available at: https://openarchive.usn.no/usn-xmlui/handle/11250/2829351
Search in Google Scholar Back to article
Henriksen, M., Gaathaug, A.V., Vaagsaether, K., Lundberg, J., Forseth, S. and Bjerketvedt, D. (2020) ‘Laminar burning velocity of the dimethyl carbonate-air mixture formed by the Li-ion electrolyte solvent’, Combustion, Explosion, and Shock Waves, 56, pp. 383–393. Available at: 10.1134/S0010508220040024
Open DOI Search in Google Scholar Back to article
Henriksen, M., Vaagsaether, K., Lundberg, J., Forseth, S. and Bjerketvedt, D. (2019) ‘Explosion characteristics for Li-ion battery electrolytes at elevated temperatures’, Journal of Hazardous Materials, 371, pp. 1–7. Available at: 10.1016/j.jhazmat.2019.02.108
Open DOI Search in Google Scholar Back to article
Henriksen, M., Vaagsaether, K., Lundberg, J., Forseth, S. and Bjerketvedt, D. (2021) ‘Laminar burning velocity of gases vented from failed Li-ion batteries’, Journal of Power Sources, 506, p. 230141. Available at: 10.1016/j.jpowsour.2021.230141
Open DOI Search in Google Scholar Back to article
Liu, X. and Zhang, Q. (2014) ‘Influence of initial pressure and temperature on flammability limits of hydrogen-air’, International Journal of Hydrogen Energy, 39(12), pp. 6774–6782. Available at: 10.1016/j.ijhydene.2014.02.001
Open DOI Search in Google Scholar Back to article
Mashuga, C.V. and Crowl, D.A. (1999) ‘Flammability zone prediction using calculated adiabatic flame temperatures’, Process Safety Progress, 18(3), pp. 127–134. Available at: 10.1002/prs.680180303
Open DOI Search in Google Scholar Back to article
Mazloomi, K. and Gomes, C. (2012) ‘Hydrogen as an energy carrier: Prospects and challenges’, Renewable and Sustainable Energy Reviews, 16(5), pp. 3024–3033. Available at: 10.1016/j.rser.2012.02.028
Open DOI Search in Google Scholar Back to article
Razus, D., Brinzea, V., Mitu, M., Movileanu, C. and Oancea, D. (2011) ‘Temperature and pressure influence on maximum rates of pressure rise during explosions of propane-air mixtures in a spherical vessel’, Journal of Hazardous Materials, 190(1–3), pp. 891–896. Available at: 10.1016/j.jhazmat.2011.04.018
Open DOI Search in Google Scholar Back to article
Riley, J.F. (1992) Inergen: A breathable gaseous extinguishing agent. Available at: https://www.nist.gov/system/files/documents/el/fire_research/R0301006.pdf
Search in Google Scholar Back to article
Savitzky, A. and Golay, M.J.E. (1964) ‘Smoothing and differentiation of data by simplified least squares procedures’, Analytical Chemistry, 36(8), pp. 1627–1639. Available at: 10.1021/ac60214a047
Open DOI Search in Google Scholar Back to article
Schroder, V. and Molnarne, M. (2005) ‘Flammability of gas mixtures part 1: Fire potential’, Journal of Hazardous Materials, 121(1–3), pp. 37–44. Available at: 10.1016/j.jhazmat.2005.01.032
Open DOI Search in Google Scholar Back to article
Smith, G.P., Golden, D.M., Frenklach, M., Moriarty, N.W., Eiteneer, B., Goldenberg, M., Bowman, C.T., Hanson, R.K., Song, S., Gardiner, W.C., Jr., Lissianski, V.V. and Qin, Z. (1999) GRI-MECH 3.0.
Search in Google Scholar Back to article
The International Maritime Organization. (2023) IMO’s work to cut GHG emissions from ships. Available at: https://www.imo.org/en/MediaCentre/HotTopics/Pages/Cutting-GHG-emissions.aspx
Search in Google Scholar Back to article
Ustolin, F., Campari, A. and Taccani, R. (2022) ‘An extensive review of liquid hydrogen in transportation with focus on the maritime sector’, Journal of Marine Science and Engineering, 10(9), p. 1222. Available at: 10.3390/jmse10091222
Open DOI Search in Google Scholar Back to article
Van den Schoor, F., Norman, F., Vandermeiren, K., Verplaetsen, F., Berghmans, J. and Van den Bulck, E. (2009) ‘Flammability limits, limiting oxygen concentration and minimum inert gas/combustible ratio of H₂/CO/N₂/air mixtures’, International Journal of Hydrogen Energy, 34(4), pp. 2069–2075. Available at: 10.1016/j.ijhydene.2008.12.038
Open DOI Search in Google Scholar Back to article

Articles in this issue

DOI: https://doi.org/10.58895/hysafe.26

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Language: English

Page range: 68 - 75

Submitted on: Jul 24, 2025

Accepted on: Aug 22, 2025

Published on: Oct 17, 2025

Published by: KIT Scientific Publishing

In partnership with: Paradigm Publishing Services

Keywords:

Inergen,

explosion mitigation,

flammability limits,

deflagration index,

oxygen limiting,

minimum inerting concentration

© 2025 Mathias Henriksen, Dag Bjerketvedt, published by KIT Scientific Publishing
This work is licensed under the Creative Commons Attribution 4.0 License.

Volume 2 (2025): Issue 1