In the event of a battery energy storage system (BESS) fire, a gut reaction may be to douse the system in water. But that’s not always the best response.
Battery experts instead suggest a more defensive cooling approach that prioritizes fire containment over fire suppression.
“We primarily deal with two hazards: normal fire events and explosion events,” Mishaal SyedNaveed, a senior fire protection engineer at Wärtsilä Energy Storage, told pv magazine USA. He explained that battery failure risks thermal runaway, which boosts the risk of explosions if gases ignite. As such, SyedNaveed noted, directly spraying liquid on the battery enclosure can actually make things worse.
“Using water to fight the fire can actually exacerbate the situation and lead to arcing or short-circuiting,” he said. What he recommends fire authorities do is to take a more defensive approach and stay out of the enclosure.
“Not taking an offensive approach is contradictory behavior for a lot of the people who serve the fire departments,” he said, acknowledging that usually, water is the best solution to put out fires. But with batteries, you need to let the fuel consume itself and focus on preventing the fire from propagating and on cooling adjacent cells.
Implementing the cooling strategy can be as straightforward as changing the nozzle pattern on the fire hose.
“Put it in a fog pattern and we use that to cool the surrounding modules,” SyedNaveed explained. “You don’t need to apply water directly to the initiating battery.”
Making sure modules are set back from each other and having that spatial separation is also important, he added.
SyedNaveed explained that Wärtsilä partners with the Fire & Risk Alliance to provide training programs for first responders that balance the necessary technical knowledge with on-the-ground experience.
“We have firefighters help other firefighters,” he said. “That mindset helps.”
In those workshops, first responders will typically go on a walkthrough of a battery site and learn how batteries could fail and how to mitigate those events safely if they do occur.
Still, training and testing are only one piece of the puzzle. Though regulations are slowly catching up, fragmentation across U.S. jurisdictions remains a barrier to a unified fire code.
SyedNaveed noted that this is changing; NFPA 855, a model fire code for energy storage systems, is gaining traction as a foundation for safety planning.
“It’s a global standard that derives from the U.S.,” he explained, “but the content and recommendations are being adopted by a lot of other places around the world.”
But, he added, design verification and robust testing are essential while technology continues to outpace the regulation.
“Like all industries, the tech is here and the codes aren’t there yet,” he noted.
Ultimately, in his eyes, bridging the gap between emergency responders and engineering professionals is key to preventing battery fires from becoming disasters.
“We should as a community make better understanding and piece out misinformation,” SyedNaveed said. “These things are not dangerous bombs…having a robust design and adequate understanding of the technology can make all the difference.”
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