Cruise & Ferry Review - Autumn/Winter 2023

130 VIEWPOINT Over the past decade, the number of fires occurring on the decks of ro-ro ferries has been closely monitored by Interferry, the shipping association representing the global ferry industry. In most cases, the fires have been attributed to an electrical fault, often a malfunctioning reefer unit. However, the industry has raised concerns over how best to manage fires emanating from the lithium-ion (Liion) battery-powered electric vehicles (BEVs) that are gradually replacing the classic petrol and diesel-powered vehicles (ICEVs) carried onboard ro-ro ferries. Questions have also been asked about the efficacy of a fixed water-based extinguishing system (drencher system) in relation to Li-ion battery fires. Between September 2019 and August 2023, Interferry collaborated with other members of LASH FIRE, a European Union-led research project, to develop and validate effective operational and design solutions to significantly reduce the risk of BEV fires onboard ro-ro ships. As part of this project, LASH FIRE has performed tests comparing the fire suppression performance of a drencher system for both ICEV and BEV fires. Relative to the total number of vehicles, the number of BEV fires is lower than ICEV fires. Even so, stringent measures related to the carriage of BEVs have been discussed, including everything from installing additional firefighting capabilities, to segregating BEVs onboard or prohibiting BEVs on ro-ro decks. This is because several factors make it very difficult to extinguish a fire within a battery pack. First, the plastic housing of the battery pack acts as a shield for the extinguishing agent (for example water), and secondly, the battery pack will also be shielded by the vehicle’s body. Plus, the chemical components within the battery cells provide a high-density energy source to sustain the fire locally. This shielding effect is mostly relevant if the fire starts in the BEV’s battery, which is typically caused by a short circuit leading to a so-called thermal runaway. When the fire does not originate in the battery, the suppression activities will hinder its spread and significantly reduce the risk of a thermal runaway. A BEV may also end up on fire when stowed adjacent to a vehicle that catches on fire, but in this scenario the consequences are no worse than if it were a petrol or diesel car by virtue of the unlikeliness of the BEV’s battery experiencing a thermal runaway. In fact, a non-battery-related fire in a BEV will likely release less heat than one involving liquid fuel in a tank because a plastic fuel tank will catch fire much faster than a Li-ion battery. LASH FIRE carried out a series of tests comparing the fire suppression performance of a drencher system for fires involving ICEVs and BEVs, respectively. The tests simulated a ro-ro space with a five-metre-high ceiling and a fire suppression system designed in line with International Maritime Organization’s revised guidelines for the design and approval of fixed water-based firefighting systems for ro-ro and special category spaces (MSC. 1/Circ. 1430/Rev. 2). Representative of today’s modern vehicles, LASH FIRE used two pairs of geometrically similar SUV-type By Johan Roos, Interferry Fighting electric fires on ferries Tests conducted by the EU’s LASH FIRE project show that conventional seawater drencher systems can effectively contain battery electric vehicle fires onboard vessels Watch LASH FIRE’s webinar about BEV fires on the decks of ro-ro ferries: “ BEVs are no more hazardous than ICEVs, yet the risks of Li-ion batteries differ to those of conventional fuels”