Description
Transit authorities around the globe are pursuing the transition of their bus fleets, particularly to battery electric buses (BEBs). As more BEBs become operational, the risk of fire origination due to thermal runaway events on the road is likely to rise. This becomes a particular concern in underground infrastructures, specifically for road tunnels. Water-based fixed fire fighting systems (FFFS) and emergency ventilation systems (EVS) are often used to control backlayering from such vehicular fire events and provide cooling to the surroundings. This study investigates the impact of FFFS and EVS on an 18.3 m long articulated BEB fire in a road tunnel environment. The results of this study showed a significant reduction in exposure temperatures of the tunnel structures and minimized risk of fire spread to stopped adjacent vehicles due to the operation of FFFS. The integrations of EVS and FFFS showed greater cooling of the combustion products from the fire, and both deluge and mist systems were found to be effective in providing tenable conditions upstream of the fire. The study was performed using FDS, without establishing grid independence, and field validation of the results. Therefore, caution is suggested when using the results and conclusions of this study.
