What is the preferred agent for extinguishing polar solvent flammable liquids?

The preferred agent for extinguishing polar solvent flammable liquids is alcohol resistant Class B foams. Polar solvents, such as alcohols and ketones, have unique properties that make them challenging to extinguish. They have a low flash point and can mix with water, which can lead to a hazardous situation when trying to use water alone for suppression.

Alcohol resistant Class B foams are specifically formulated to effectively smother and suppress fires involving polar solvents. These foams create a barrier that prevents the fuel from vaporizing and can form a thick blanket over the fuel, helping to inhibit re-ignition. This makes them the most effective choice compared to other extinguishing agents.

Using water, for instance, could spread the fire due to the miscibility of water and polar solvents, while dry powder extinguishers may not provide the same level of suppression and may require specific application techniques to be effective against these types of fires. AFFF Class A foam is designed for Class A fires and may not adequately address the unique challenges posed by polar solvents. Therefore, the use of alcohol resistant Class B foams is preferred for ensuring an effective and safe firefighting response in these scenarios.