Class K fire extinguishers are specifically designed to combat fires involving cooking oils and fats, typically found in commercial kitchens. The primary method they use to extinguish fires is through a chemical reaction known as saponification.
When the alkaline agent in a Class K extinguisher comes into contact with the burning cooking oil, it reacts with the fat to create a soap-like substance. This reaction not only helps to cool the flames but also effectively encapsulates the burning material, thereby inhibiting the fire's ability to continue burning. This chemical process is crucial because it specifically targets the nature of the fires fueled by oils, unlike other methods that might be employed in different classes of fires.
Therefore, the use of an alkaline mixture that leads to saponification is the most effective method for suppressing Class K fires, making this response the correct one. Understanding this process is vital for anyone involved in fire safety, particularly in environments with high risks of cooking-related fires.