Literature study: The performance of carbon dioxide systems on ro-ro vehicle carriers

The performance of carbon dioxide systems during vehicle fires on ro-ro vehicle carriers has not been documented. The first part of the report documents such fires. From 2013 to 2023, at least 22 severe fires started in the cargo space of ro-ro vehicle carriers. Eight fires started during loading operations (i.e., when the doors and ramps are open) and fourteen started while at sea. In eleven of the 22 fires, the found information verifies that a carbon dioxide system was used. In five of these verified incidents, the fire was suppressed or extinguished, in five of the incidents the fire was not suppressed nor extinguished, and in one case information about the performance is lacking. For the cases when fire was not extinguished, a long delay time combined with the fact that the space was not sufficiently sealed may explain the failure. Electrical failure, including short circuits, is a commonly noted fire cause in used cars onboard. One of the 22 fires probably originated in a new production electric vehicle; no other fires in electric vehicles were documented. The second part of the report documents fire suppression tests. However, there are few fire suppression tests with lithium-ion batteries and carbon dioxide in the scientific literature. Findings include small-scale tests with handheld/portable fire extinguishers and not fixed, total-flooding systems. The identified studies indicates that full fire extinguishment of lithium-ion battery fires may not be possible with carbon dioxide. While carbon dioxide may not extinguish and cool down a battery cell effectively to prevent thermal runaway propagation, it may reduce the risk of fire spreading to nearby vehicles and other combustible materials. This has not been investigated and is part of the upcoming objectives in the COFFEE project. Traditional search tools and engines were used to collect fire investigation reports, media articles, and research studies for this report.