Following several high-profile ship fires involving electric vehicles (EVs), Survitec has produced some valuable advice for operators of vessels transporting hybrid and EVs, such as ferries, ropaxes, RoRos, PCCs and PCTCs, on how best to prevent and control fire onboard ships involving lithium-ion battery powered vehicles.
According to Survitec there are a number of ongoing initiatives within the industry to improve safety in this area. There is a desire to develop early fire detection systems to better monitor and protect car decks and lithium-ion batteries installed in vehicles onboard.
Any slight deviation in their properties can provide an early indication that conditions are right for a fire and afford time to take preventative measures to protect or quarantine hybrid and EVs.
Pre-ignition signs of a battery fire include heat and smoke from parts of the vehicle where the battery is usually placed, popping sounds from battery cells, and toxic gas emissions.
While early detection solutions are readily available, Rafal Kolodziejski, Survitec’s Head of Product Support & Development Fire Systems, revealed that these systems are not yet adapted to allow for pre-fire conditions specific to lithium-ion batteries.
Monitoring car decks for early-stage fire conditions, typically any fluctuation in temperature or atmospheric condition, is critical to preventing fire propagation. The type and location of sensors are vitally important.
Water-based solutions provide the best cooling effect, which is crucial in the case of this type of fire. However, the volume of water required to control an EV deck fire could impact ship stability, so a suitable drainage system must also be considered.
Survitec further adds that research shows that a water mist system has the highest efficiency for this type of fire. However, because battery modules are installed under the floor in most EVs, the most significant heat will be generated at deck level.
There are various R&D initiatives investigating the best water spraying method for this. One of these solutions is a pop-up nozzle that sprays water mist upwards and is fixed, and mobile solutions are now at the testing stage.
“Prevention is certainly better than the cure at the moment. Early monitoring and detection are becoming increasingly important safety factors for ship operators and crew. With an EV cargo, the earlier the crew can detect pre-fire conditions, the better,” said Mr. Kolodziejski.