To extinguish Class B fires, what technique is recommended?

To extinguish Class B fires, which involve flammable liquids and gases, smothering the fire is the recommended technique. This method works by depriving the fire of oxygen, which is one of the essential components of the fire triangle (heat, fuel, and oxygen). By eliminating the air surrounding the fire, the combustion process is interrupted, effectively extinguishing the flames.

Using water to cool a Class B fire is ineffective and can be dangerous because water can cause flammable liquids to spread or react violently. Similarly, while sand or dirt can sometimes help smother a fire, they may not always be practical or effective depending on the size or nature of the fire. Evacuating the area is a critical safety measure, but it is not an extinguishing technique. Instead, it is a step taken to protect lives while addressing the fire situation appropriately. Therefore, smothering the fire is the most direct and effective method for extinguishing Class B fires.