Gill, Jason Peter ORCID: https://orcid.org/0000-0003-3456-9820
(2024)
Gas Explosions in, and Propagating from, Low Strength Enclosures.
PhD thesis, University of Leeds.
Abstract
This research aimed to investigate the escalating effects of explosion propagation from electrical control boxes within lightweight steel-constructed buildings, focusing on elucidating the flame propagation mechanisms responsible for intensifying Vapour Cloud Explosion (VCE) severity, as observed in the Buncefield incident of 2005. The research aimed to determine if any escalating effects could be caused by the explosion propagating from the control box and the building into a larger cloud.
A series of controlled explosion experiments were conducted using a 47 m3 vessel designed to mimic the structural properties of buildings like the Buncefield pumphouse, where it is believed the cloud was first ignited. Initially, experiments utilising 4.2% propane-air mixtures were carried out to understand baseline venting mechanisms and pressure development, with the vessel vent covered with steel panels and, for comparison, plastic sheeting. Findings indicate that lightweight steel panels hinging open during the initial stages of an explosion significantly enhance explosion severity due to their function as congestion elements.
Subsequent experiments employed commercially available electrical control boxes to investigate the explosion propagation dynamics, resultant pressures, and flame speeds. Experiments were conducted without and with a flammable cloud of 8 m3 external to the control box contained in a tent. High-speed venting from the control box demonstrated a localised increase in flame speeds and overpressures, albeit the flame speeds attenuated considerably with a 0.35 m travel. However, congestion placed 0.5 m away from the vent without confinement didn’t result in increased flame speeds.
The observed escalated explosion severity in lightweight steel buildings on high VCE hazard sites reveals a pressing concern regarding their structural failure mechanisms. Explosions originating from electrical control boxes showed an amplification of explosion severity, which only affected the immediate volume close to the box, suggesting that an obstruction-free zone of approximately 0.5 m from the control box could prevent an escalating explosion event. However, further studies are needed to thoroughly map the roles of confinement, immediate congestion, and high reactivity gases in such scenarios. Overall, this research significantly contributes to a better understanding of explosion propagation dynamics within industrially relevant and standard settings, thereby aiding in developing more robust safety measures and structural designs to mitigate the severity of VCEs.
Metadata
Supervisors: | Phylaktou, Herodotos and Andrews, Gordon |
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Keywords: | Vapour Cloud Explosion; VCE; Buncefield; explosion investigation; confined explosions; propagating explosion |
Awarding institution: | University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering (Leeds) > School of Chemical and Process Engineering (Leeds) |
Depositing User: | Mr Jason Peter Gill |
Date Deposited: | 20 May 2024 11:47 |
Last Modified: | 20 May 2024 11:47 |
Open Archives Initiative ID (OAI ID): | oai:etheses.whiterose.ac.uk:34889 |
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