Early Battery Fire in New Energy Vehicles: Intervention Effect and Practical Guide of Fiberglass Fire Blankets
Introduction
In 2025, the U.S. Fire Administration and NFPA issued a joint safety advisory specifically addressing fiberglass fire blankets and electric vehicle fires. It highlighted something important: EV battery fires are a different problem from conventional vehicle fires, and the intervention approach needs to reflect that.
This isn't a reason to avoid fire blankets for EVs. It's a reason to understand how they work, what they're designed to do, and what their limitations are — so they're used correctly rather than incorrectly.
The global EV fleet is growing rapidly. With it, lithium-ion battery fire incidents are increasing in frequency. California parking lot fires, the Morning Midas cargo ship incident involving 800 electric vehicles in the Pacific, increased EV battery fire reports in the Netherlands and Australia — these are not edge cases. They're a preview of what happens when battery technology scales faster than first-response infrastructure.
This guide covers what early-stage EV battery intervention looks like, how a fiberglass fire blanket works in that context, and the practical steps every EV driver should know.
Why EV Battery Fires Are Uniquely Difficult
Thermal runaway in a lithium-ion battery pack doesn't follow the same rules as a petrol or diesel engine fire. Understanding why changes how you respond.
Self-sustaining combustion. When a lithium battery cell enters thermal runaway — triggered by collision damage, overcharging, manufacturing defects, or external heat — it generates its own oxygen through chemical decomposition. Unlike a fuel fire, which dies when external oxygen is cut off, a battery fire can sustain itself internally. This is the fundamental reason why conventional suppression methods that rely purely on oxygen deprivation are less effective on a fully developed battery fire.
Underfloor location. EV battery packs sit beneath the vehicle floor — not in the engine bay. The heat source is distributed across the entire underfloor area, which changes both suppression geometry and the blanket sizing requirements. A blanket that covers only the bonnet doesn't address the actual fire location.
Toxic gas release. Thermal runaway releases hydrogen fluoride and other hazardous gases — a serious respiratory hazard for anyone in proximity. This is one reason the NFPA/USFA advisory emphasised that professional firefighters require full protective equipment including self-contained breathing apparatus throughout EV fire incidents.
Re-ignition risk. EV battery fires can reignite hours or even days after appearing fully suppressed. Water immersion of the battery pack is currently the most reliable method for full extinguishment — but that requires equipment most drivers don't carry.
| EV Battery Fire Characteristic | Implication |
|---|---|
| Self-sustaining combustion | Oxygen deprivation alone may not fully extinguish |
| Underfloor battery location | Full-vehicle blanket coverage required, not just front |
| Toxic gas release | Evacuation mandatory — minimum 15–20m from vehicle |
| Re-ignition risk | Professional assessment required before declaring safe |
| Extreme temperatures | Blanket must tolerate 800°C+ short-burst events |
What a Fiberglass Blanket Actually Does in an EV Fire
This is worth being precise about, because the answer is more nuanced than "it puts the fire out."
For a petrol or diesel engine fire, a correctly deployed blanket cuts off external oxygen and suppresses the fire. That's a clean and complete outcome if the blanket is deployed early enough.
For an EV battery fire, the function is different — and the NFPA advisory is right to make this distinction. A fiberglass blanket in an EV fire scenario is primarily a containment tool, not a complete extinguishment tool. Here's what it does:
Slows the thermal cascade. In early-stage thermal runaway, before the full battery pack is involved, cutting off external oxygen limits the rate at which the reaction spreads. The blanket doesn't stop the chemical process inside the cells — but it reduces the heat feedback loop from the external environment.
Prevents fire spread to surrounding vehicles and structures. This is the most clearly documented benefit. A blanket deployed over a burning EV significantly limits flame spread to adjacent vehicles — critical in underground car parks and multi-storey structures where EV fires present the greatest risk to surrounding property.
Buys evacuation time. Even if the blanket doesn't fully suppress the fire, it reduces radiant heat output and visible flame — giving bystanders and occupants more time to evacuate safely.
Limits environmental contamination. Contained fire spread means less burning material, less toxic runoff from suppression water, and more manageable incident management for professional responders.
What it doesn't do: fully extinguish a battery pack that's in advanced thermal runaway. For that, sustained water immersion is required — something only fire services can safely manage.
The new German standard DIN SPEC 91489:2024 — the first official standard specifically developed for EV fire blankets — acknowledges this explicitly. It classifies these products as "fire limitation blankets," not extinguishment tools. The standard requires the blanket to withstand direct flame exposure at 700–1,000°C for a sustained period without developing holes or seam failure.
Practical Guide — What to Do in an Early-Stage EV Battery Fire
The key word here is early-stage. If thermal runaway has already fully progressed to a fully involved battery pack with active flame from the underfloor, the situation requires professional response. But in the first few minutes — where smoke or heat is detected but open flame is limited — intervention is possible and meaningful.
Step 1: Don't open any doors, windows, or the bonnet. Introducing oxygen accelerates the reaction. Keep everything closed.
Step 2: Get everyone out and away immediately. A minimum of 15–20 metres. Toxic gas release begins early in thermal runaway — don't linger near the vehicle. This is non-negotiable.
Step 3: Retrieve the blanket. The EV battery fire blanket should be stored in the boot or rear compartment. Pull the release tab and shake fully open — under 15 seconds.
Step 4: Approach from upwind only. Wind at your back. Hold the blanket by corner handles, keeping it between you and the vehicle as a radiant heat shield as you approach.
Step 5: Deploy over the full vehicle — not just the front. EV battery packs run the full length of the underfloor. The blanket must cover the entire vehicle footprint with edges sealed to the ground on all sides. This is why EV blanket sizing requirements are larger than those for petrol vehicles.
Step 6: Retreat immediately and call emergency services. Report specifically that it is an electric vehicle fire and that thermal runaway may be involved. This determines what equipment the fire service will bring.
Step 7: Do not approach the vehicle again. Even with the blanket deployed, toxic gas continues to be released. Stay back and let professionals manage the rest.
For context on how this compares to other vehicle fire suppression approaches, this article is worth reading: Emergency Fire Suppression of Small-Scale Fires: The Core Role of Fiberglass Fire Blankets.
Selecting the Right Blanket for EV Applications
Standard vehicle fire blankets are not automatically appropriate for EVs. The sizing, temperature rating, and material specifications need to match the EV fire risk profile.
| EV Type | Minimum Blanket Size | Required Temp Rating |
|---|---|---|
| Small EV / city car | 6m × 8m | 550°C continuous / 1,000°C burst |
| Standard EV sedan | 6m × 8m | 550°C continuous / 1,000°C burst |
| EV SUV / crossover | 6m × 9m | 550°C continuous / 1,000°C burst |
| Large EV / premium | 6m × 9m | 550°C continuous / 1,000°C burst |
| Electric commercial van | 6m × 9m+ | High-silica specification recommended |
For EV applications, high-silica fiberglass with vermiculite coating is the preferred specification — providing sustained performance at higher temperature ranges and better thermal insulation across the extended blanket deployment period typical of EV incidents.
A qualified fiberglass fire blanket supplier should specify fiber grade, coating type, and temperature rating clearly in product documentation — and should be able to provide DIN SPEC 91489:2024 compliance documentation for EV-specific applications.
For a broader overview of how to match blanket specs to vehicle type, this guide covers the selection process in full: Selection & Correct Use of Fiberglass Fire Blankets for Different High-Risk Scenarios.
FAQ
Q1: Can a fiberglass fire blanket fully extinguish an EV battery fire? Not in the way it extinguishes a petrol engine fire. A fiberglass blanket for EV applications functions as a fire limitation tool — slowing thermal runaway spread, containing flame spread to surrounding vehicles, and buying evacuation time. Full extinguishment of an advanced battery pack requires sustained water immersion by professional fire services.
Q2: What is DIN SPEC 91489 and why does it matter for EV fire blankets? Published in November 2024, DIN SPEC 91489 is the first official standard specifically developed for fire limitation blankets used on electric vehicles. It requires the blanket to withstand direct flame exposure at 700–1,000°C for a sustained period without structural failure. It also addresses electrostatic safety and mechanical durability — requirements that were not covered by earlier fire blanket standards.
Q3: Is it safe to deploy a fire blanket on an EV alone? Deploying a large blanket over an EV is difficult for one person and carries risk — including toxic gas exposure. If possible, deploy with a second person. In all cases, approach only from upwind, hold the blanket as a heat shield, and retreat immediately after deployment. If the fire has progressed significantly, don't attempt intervention — evacuate and call emergency services.
Q4: How is EV blanket sizing different from petrol vehicle blankets? EV battery packs run under the full floor of the vehicle, not just the engine bay. This means the thermal footprint is wider and lower than a combustion engine fire. EV blankets need to cover the entire vehicle footprint with edges sealed to the ground — requiring larger dimensions than equivalent petrol vehicle blankets.
Q5: What should I tell emergency services when reporting an EV fire? Specify that it is an electric vehicle, that lithium-ion battery thermal runaway may be involved, and whether a fire blanket has been deployed. This information determines the equipment and tactics the fire service brings to the scene. EV fires require different resources than standard vehicle fires.
Conclusion
EV battery fires are not a reason to avoid fiberglass fire blankets — they're a reason to understand what those blankets do and what they don't do. Used correctly in early-stage thermal runaway, a correctly sized and rated custom fiberglass fire blanket limits fire spread, protects surrounding vehicles, and buys critical time for evacuation and professional response.
The standards now exist — DIN SPEC 91489:2024 being the most significant recent development — to define what EV-appropriate blankets need to perform. Buy to those standards, store the blanket accessibly, know the seven-step process, and understand where the line is between early-stage intervention and full evacuation.
For EV-specific product specifications and certification documentation, contact the INSOFIRE team at sales@insofire.com or visit the product catalog.
About INSOFIRE
INSOFIRE — InsoFire Material Technology Hangzhou Co., Ltd. — has been manufacturing fiberglass-based fire protection products since 1993. With over 30 years of expertise and a 33,000 m² production facility in Hangzhou, China, the company supplies car fire blankets, standard fire blankets, e-bike fire blankets, and custom fireproof solutions for automotive, industrial, and commercial clients globally. All products carry EN, ISO, ASTM, AS/NZS, and FM certifications. OEM and ODM production supported. Contact: sales@insofire.com or browse the full product range.
