A fire blanket in a laboratory is a safety device used to smother small fires and to protect people whose clothing has caught fire. It works by cutting off the oxygen supply to flames, and it’s one of the simplest, fastest tools available when a fire breaks out on a benchtop or on a person. Most lab fire blankets are made of fiberglass coated with fire-retardant substances, and they’re typically mounted on the wall in a quick-release container near exits and workstations.
How a Fire Blanket Extinguishes Flames
Fire needs three things to burn: heat, fuel, and oxygen. A fire blanket removes the oxygen. When you drape the blanket over a small fire, it creates a seal between the flames and the surrounding air, suffocating the fire in seconds. This makes it especially effective for contained fires, like a beaker of solvent that ignites on a lab bench or a small spill that catches a spark.
The smothering approach has a particular advantage over fire extinguishers in certain situations. Spraying a chemical fire extinguisher can scatter burning liquid or send a cloud of powder across delicate equipment. A fire blanket, placed carefully, contains the fire exactly where it is. For grease or oil-based fires (classified as Class K or Class F), smothering is often the preferred first response because water and some extinguisher types can cause these fires to spread or re-ignite violently.
Using a Fire Blanket on a Person
The most critical use of a lab fire blanket is wrapping it around someone whose clothing is on fire. OSHA guidance identifies fire blankets alongside safety showers as appropriate responses to clothing fires in laboratory settings. The technique is straightforward: wrap the blanket around the flames and the person, get them to drop to the ground, and have them roll until the fire is out. The goal is to cut off airflow to the burning fabric as quickly as possible.
There is one important caveat. If the person has been splashed with reactive chemicals or if electricity is involved, a fire blanket may not be the right choice. OSHA specifically notes that safety showers should not be used when chemicals or electricity are factors, and similar caution applies to blankets in those scenarios. A blanket can trap reactive chemicals against the skin, potentially worsening a chemical burn. In those cases, the response depends on the specific hazard.
What Fire Blankets Work Best On
Fire blankets are designed for small, contained fires. In a lab setting, that typically means:
- Small solvent fires in beakers, flasks, or on bench surfaces
- Clothing fires on a person
- Waste bin fires or small paper and fabric fires
- Hot plate or heating mantle fires where equipment ignites nearby materials
They are not meant for large or spreading fires. If a fire has grown beyond the size that a single blanket can cover, or if it involves pressurized gas lines, an extinguisher or evacuation is the appropriate response. Fire blankets also won’t work on fires fueled by substances that generate their own oxygen, such as certain oxidizers common in chemistry labs. Those fires will continue burning even without ambient air.
Materials and Temperature Limits
Lab-grade fire blankets are almost always woven fiberglass. The glass fibers are naturally non-flammable, and the blanket is coated with additional fire-retardant material to improve performance and durability. Fiberglass blankets can typically withstand temperatures well above what a small benchtop fire produces, though prolonged exposure to extreme heat makes the material brittle and compromises its structure.
The fiberglass construction also means these blankets won’t melt onto skin the way a synthetic fabric would, which is why they’re safe to wrap around a person. They’re flexible enough to conform around someone’s body but rigid enough to hold their shape when draped over a container.
Where Fire Blankets Are Placed
There is no single OSHA or NFPA standard that mandates fire blankets in every laboratory. OSHA’s laboratory safety guidance references them as one of several tools for responding to clothing fires, alongside safety showers and fire extinguishers, but doesn’t prescribe exact placement rules the way it does for eyewash stations or extinguishers. In practice, most universities and institutional safety offices require them as standard equipment in any lab where flammable materials are handled.
You’ll usually find them mounted on the wall in a vertical pull-down container, positioned near the room’s exit so you don’t have to move deeper into a fire to reach one. They should be visible and unobstructed. If you work in a lab and don’t know where the fire blanket is, that’s worth checking before you need it.
Inspection and Replacement
Fire blankets require annual inspections at minimum. The University of Rochester’s Environmental Health and Safety department, like most institutional safety programs, checks that the blanket is still in its container, free of holes, burn marks, and frayed edges. The inspection is simple, but it matters. A blanket with even a small hole won’t form the airtight seal needed to smother a fire effectively.
Most fire blankets are designed for single use. After being deployed on an actual fire, the blanket should be replaced even if it looks intact. Exposure to high heat can weaken fiberglass fibers internally, making them brittle in ways that aren’t always visible. If the blanket was used on a very minor fire and shows no tears, burns, or stiffness, some manufacturers say it can be reused, but the standard practice in laboratory settings is to replace it. Given that a new fire blanket costs relatively little compared to the consequences of one failing, replacement is the safer default.
Fire Blankets vs. Fire Extinguishers
Fire blankets and extinguishers serve different roles, and a well-equipped lab has both. Extinguishers can handle larger fires and can be aimed from a distance. Fire blankets require you to get close to the fire, which limits their use to small, accessible flames. But blankets have advantages that extinguishers don’t: they’re silent, they don’t create a mess of chemical residue, they don’t risk scattering burning liquid, and they can be wrapped around a person.
For a small container fire on a lab bench, a fire blanket is often the fastest and cleanest response. You don’t need to check the extinguisher class, pull a pin, or aim a nozzle. You pull the blanket from its case and lay it over the fire. That simplicity is the point. In the first few seconds of a lab fire, when the situation is still small and manageable, the tool you can use immediately is the one that matters most.