Fettbrandlöscher

Fettbrandlöscher, also known as Class F fire extinguishers or Class K fire extinguishers in some regions, are specialized fire extinguishing devices designed to combat fires involving cooking oils and fats. These types of fires, often occurring in kitchens or commercial food preparation areas, are particularly dangerous because water is ineffective and can actually spread the flames.

The extinguishing agent used in a Fettbrandlöscher is typically a wet chemical solution, most commonly potassium acetate, potassium carbonate, or potassium citrate. When sprayed onto a burning fat or oil, this wet chemical undergoes an endothermic reaction, absorbing heat and cooling the fuel below its ignition point. Simultaneously, it forms a foam blanket on the surface of the burning liquid, which smothers the fire by preventing oxygen from reaching the fuel. This dual action of cooling and smothering makes Fettbrandlöscher highly effective for these specific types of fires.

Standard fire extinguishers, such as those for Class A (ordinary combustibles) or Class B (flammable liquids), are not suitable for grease fires. Using a water-based extinguisher on a grease fire can cause a violent reaction, splashing the burning oil and rapidly spreading the fire. Similarly, dry chemical extinguishers designed for Class B fires may not be sufficient to cool the oil below its re-ignition temperature, leading to re-flaming. Therefore, having a Fettbrandlöscher readily accessible in kitchens where cooking oils and fats are used is a crucial safety measure. They are often identified by a specific Class F or Class K label on the extinguisher.