Research finds fire blankets may trap explosive gases during battery fires
The NFPA and UL Research Institutes have reported that using fire blankets during electric vehicle fires with battery involvement may increase explosion risk.
According to a joint notice from the Fire Protection Research Foundation (FPRF) and the Fire Safety Research Institute (FSRI), fire blankets can eliminate open flames but may trap flammable gases underneath.
The notice warned that gases accumulating beneath the blanket during battery thermal runaway could ignite explosively if oxygen is reintroduced.
Fire blankets linked to confined gas build-up in experiments
The FPRF reported that during controlled testing, fire blankets used to cover burning electric vehicles succeeded in cutting off flames by limiting oxygen flow.
However, battery thermal runaway continued even after the flames were extinguished, releasing flammable gases into the space beneath the blanket.
The Foundation stated that in some trials, this created an explosion hazard for nearby responders when the confined gases mixed with fresh air.
Four suppression methods assessed in current FPRF project
The FPRF is analysing firefighting strategies through its ongoing research project titled Assessment of EV Firefighting Tactics, Tools and the Impact on Stranded Energy.
The Foundation explained that recent testing compared the use of standard hose streams (with and without added agents), fire blankets, and firefighting appliances on electric vehicle fires.
Preliminary findings will be presented at the NFPA Conference & Expo on 16 June 2025 in Las Vegas, and full results will be published later this year at nfpa.org/foundation.
FSRI conducting parallel studies on EV fire suppression
The FSRI is independently studying battery fire hazards and suppression techniques under its Fire Safety of Batteries and Electric Vehicles programme.
According to the Institute, it is evaluating hose streams, under-vehicle water nozzles, and fire blankets as control measures in confirmed battery pack fire incidents.
The FSRI stated that analysis of video footage and performance data is ongoing, with findings to be released later in 2025 at fsri.org.
Focus remains on firefighter safety during EV incidents
The FPRF said that its research aims to support safer incident response procedures for EV fires by identifying effective tactics and understanding the risks of re-ignition and gas build-up.
The FSRI added that its work is directed at enabling better control strategies and reducing hazards for emergency responders.
Both organisations emphasised that no suppression method is without risk, and current findings should inform future training and operational guidance.
NFPA warns of fire blanket hazard in EV fire suppression: Summary
The NFPA reported that fire blankets used during electric vehicle battery fires may pose an explosion risk.
This risk arises from the accumulation of unburned flammable gases beneath the blanket.
The Fire Protection Research Foundation and the Fire Safety Research Institute issued a joint notice on 2 June 2025.
They warned that introducing air into this gas buildup could cause ignition.
The warning is based on ongoing research into EV firefighting tactics and suppression tools.
The FPRF tested four approaches: hose streams with and without additives, fire blankets, and firefighting appliances.
Preliminary results will be presented at the NFPA Conference & Expo in Las Vegas on 16 June 2025.
A full report will follow in autumn 2025 at nfpa.org/foundation.
The FSRI is conducting separate experiments under its own battery safety research project.
Its tests included standard and under-vehicle water application and fire blankets.
The FSRI will publish its findings later in 2025 at fsri.org.
Both organisations aim to improve responder safety and inform tactical decisions.