Engine Compartment Car Fire Fighting: Operation Points and Safety Standards of Fiberglass Fire Blankets
Introduction
Engine compartment fires account for the majority of vehicle fire incidents. According to the U.S. Fire Administration, engine and running gear areas are the leading origin point for highway vehicle fires — and in most cases, the fire starts small. A leaking fuel line drips onto a hot exhaust manifold. An overheating component ignites accumulated oil residue. An electrical short sparks in a wiring loom that hasn't been inspected in years.
The window for effective first-response intervention is narrow. Research cited by the NFPA shows a typical vehicle fire reaches peak heat release within the first few minutes of full ignition. After that point, portable suppression tools become significantly less effective.
A fiberglass fire blanket used correctly in that early window can suppress an engine compartment fire entirely — without the chemical residue damage of a powder extinguisher and without the re-ignition risk of CO₂. This guide covers exactly how to do that, and what safety standards to look for when choosing the right product.
Why Engine Compartment Fires Behave Differently
Engine bays are not like other fire locations. Three factors make them particularly challenging for first-response suppression.
Enclosed space with multiple fuel sources. A typical engine bay contains petrol or diesel fuel lines, engine oil, transmission fluid, power steering fluid, brake fluid, and electrical wiring — all in close proximity. A fire that starts in one system can spread to others in seconds.
The bonnet problem. Opening the bonnet during a fire is one of the most dangerous instincts a driver can act on. Lifting the bonnet introduces a surge of fresh oxygen into the engine bay — which can turn a smoldering fire into an open flame event almost instantly. A fiberglass blanket works precisely because it suppresses without requiring bonnet access.
Heat concentration. Engine fires concentrate heat in a relatively small volume. Temperatures in a developing engine bay fire can reach 600–800°C within two to three minutes of ignition. A blanket rated to handle sustained exposure at these temperatures is not a nice-to-have — it's a specification requirement.
| Engine Fire Characteristic | Impact on Suppression Method |
|---|---|
| Multiple fuel sources | Chemical extinguishers may not cover all fuel types effectively |
| Enclosed bay | Powder and CO₂ dispersal limited without direct hood access |
| Rapid heat buildup | Blanket must withstand 550°C+ continuous without structural failure |
| Re-ignition risk | Suppression tool must maintain seal after initial flame knockdown |
| Electrical involvement | Chemical residue from powder extinguisher causes secondary damage |
Step-by-Step Operation for Engine Compartment Fires
The process is straightforward. What matters is the sequence — doing steps out of order reduces effectiveness and increases risk.
Do not open the bonnet. If smoke is visible from the engine bay, the fire has started. Opening the bonnet at this point introduces oxygen to the fire. Leave it closed throughout the entire suppression process.
Move the vehicle if safe. If you can still access the ignition without approaching the fire side, move the vehicle away from traffic and away from any fuel source — petrol station forecourts, grass verges in dry conditions, other vehicles.
Turn off the engine. Cutting the ignition removes the running fuel supply from fuel-injected systems and reduces the electrical load on the wiring.
Retrieve the blanket. Pull the release tab on the storage bag — this should take under 15 seconds. Shake the blanket fully open. Hold it by the corner handles, not the centre. Keep it between you and the vehicle as you approach.
Approach from upwind and deploy. Walk toward the vehicle from the side where wind is at your back. Lower the blanket over the entire front of the vehicle — bonnet, grille, and front quarter panels — in a single continuous motion. The edges must contact the ground on all sides. Any gap creates an oxygen channel.
Retreat and wait. Once deployed, step back at least 10 metres. The blanket needs to remain in place for a minimum of 20–30 minutes. Metal components stay dangerously hot long after visible flames are suppressed. Removing the blanket early causes re-ignition.
Call emergency services. Always. A suppressed fire is not a cleared vehicle. Emergency responders will confirm the fire is fully out before the vehicle is deemed safe.
For further reading on blanket selection by fire scenario, this article covers the full range: Selection & Correct Use of Fiberglass Fire Blankets for Different High-Risk Scenarios.
Safety Standards — What to Check Before You Buy
The difference between a blanket that works and one that fails often comes down to certification. These are the standards that matter for engine compartment fire applications.
EN 1869:2019 — the primary European standard for fire blankets. Covers material performance, temperature resistance, and suppression effectiveness. A blanket meeting EN 1869 has been independently tested against defined fire scenarios.
ASTM F1989 — the equivalent U.S. standard. Specifies minimum performance thresholds for fire blanket materials including fiberglass.
AS/NZS 3504 — Australian and New Zealand standard, widely referenced in Asia-Pacific markets.
ISO 9001 — manufacturing quality management. Manufacturers adhering to ISO 9001 show significantly fewer product nonconformities across production batches, according to the 2024 Fire Safety Certification Report.
FM 4950 — Factory Mutual certification covering industrial fire suppression blankets.| Standard | Region | What It Certifies |
|---|---|---|
| EN 1869:2019 | Europe | Fire blanket material and suppression performance |
| ASTM F1989 | United States | Minimum performance thresholds |
| AS/NZS 3504 | Australia / NZ | Material and deployment standards |
| ISO 9001 | Global | Manufacturing quality management |
| FM 4950 | Global / Industrial | Industrial fire suppression performance |
A qualified fiberglass fire blanket manufacturer should be able to provide third-party test reports — not just certificate numbers — for the standards they claim. If a supplier can only show a certificate without the supporting test documentation, ask for it before committing to a purchase.
INSOFIRE products carry EN, ISO, ASTM, AS/NZS, and FM certifications, backed by full test documentation available on request.
Choosing the Right Blanket for Engine Fire Applications
Size and temperature rating are the two variables that determine whether a blanket actually works on your vehicle.
For engine compartment fires specifically, the blanket needs to cover more than just the bonnet. The edges must reach the ground on the front and both sides of the vehicle — which typically requires a blanket significantly larger than the bonnet area alone.
| Vehicle Type | Recommended Minimum Size | Temp Rating Required |
|---|---|---|
| Small hatchback / city car | 6m × 8m | 550°C continuous |
| Standard sedan | 6m × 8m | 550°C continuous |
| SUV / crossover | 6m × 9m | 550°C continuous |
| Large SUV / 4x4 | 6m × 9m | 550°C continuous |
| Van / light commercial | 6m × 9m | 550°C continuous |
Storage matters as much as sizing. A custom fiberglass fire blanket that's correctly sized but buried under cargo in the boot is not a safety tool in practice. Keep it in a location you can access in under 15 seconds without moving other items first.
For a complete guide on matching blanket specifications to vehicle type, this piece covers the full selection process: What to Know Before Buying a Fire Blanket for a Car.
FAQ
Q1: Should I ever open the bonnet during an engine fire? No. Opening the bonnet introduces fresh oxygen to the fire, which can cause an immediate and dangerous escalation — from smoke to open flame in seconds. The fiberglass blanket works precisely because it suppresses the fire through the closed bonnet, sealing the entire front of the vehicle without requiring hood access.
Q2: How long does the blanket need to stay on the vehicle? A minimum of 20–30 minutes after visible flames are suppressed. Engine components — particularly the exhaust manifold, turbocharger, and catalytic converter — retain heat for extended periods. Removing the blanket too early allows oxygen back in, which causes re-ignition. Leave it in place until emergency services confirm the vehicle is safe.
Q3: Can I reuse a fiberglass fire blanket after an engine fire? No. After deployment on a vehicle fire, the blanket has been exposed to extreme heat and structural integrity is compromised even if it appears intact. Always replace the blanket after use. This applies regardless of how long the blanket was in contact with the fire.
Q4: What certifications should an engine fire blanket have? At minimum, look for EN 1869:2019 (Europe), ASTM F1989 (United States), or AS/NZS 3504 (Australia/NZ) certification, backed by third-party test reports. ISO 9001 manufacturing certification from the supplier confirms consistent production quality across batches.
Q5: Is a fiberglass fire blanket better than a powder extinguisher for engine fires? For early-stage engine compartment fires, a fiberglass blanket offers several advantages: no bonnet access required, no chemical residue damage to engine components and wiring, and sustained suppression as long as the blanket remains sealed. A powder extinguisher is faster for active flames but leaves corrosive residue and carries re-ignition risk once the agent disperses. Many experienced drivers carry both.
Conclusion
Engine compartment fires give you a narrow window — and what you do in the first two minutes determines the outcome. A correctly sized fiberglass fire blanket supplier product, deployed without opening the bonnet, seals off the oxygen supply and suppresses the fire without the secondary damage that chemical agents cause.
The standards exist to tell you whether a blanket actually does what it claims. EN 1869, ASTM F1989, and the others listed above are not marketing badges — they're the result of independent testing against defined fire scenarios. Buy certified. Store it accessibly. Know the six steps before you need them.
For product specifications and certification documentation, visit the INSOFIRE product catalog or contact the team at sales@insofire.com.
About INSOFIRE
INSOFIRE — InsoFire Material Technology Hangzhou Co., Ltd. — has been manufacturing fiberglass-based fire protection products since 1993. Operating from 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.
