Understanding How a Wet Chemical Fire Extinguisher Works: A Simple Guide


Fire safety is of utmost importance in protecting lives and property. Having the right knowledge about fire extinguishers and their functionality is essential for everyone. In this blog, we will explore the working principle of a wet chemical fire extinguisher, which is specifically designed to combat kitchen fires caused by cooking oils and fats. Understanding how this type of extinguisher functions can help you effectively respond to such fire emergencies.

What is a Wet Chemical Fire Extinguisher?

A wet chemical fire extinguisher is a specialised type of fire extinguisher designed to tackle fires involving cooking oils and fats. It contains a specially formulated solution that works by cooling the fire and preventing re-ignition.

Working Principle:

  1. Cooling Effect:

When a fire occurs in a kitchen, such as a grease fire, the wet chemical extinguisher is designed to quickly reduce the temperature of the burning oil or fat. The extinguishing agent, which is a potassium-based solution, creates a cooling effect on the fire, helping to lower the temperature and prevent the flames from spreading.

  1. Chemical Reaction:

The wet chemical solution not only cools the fire but also reacts with the hot cooking oils or fats. This chemical reaction forms a soapy layer on the surface of the burning material, effectively sealing it off from oxygen this is known as saponification. This prevents the fire from re-igniting and helps to smother the flames, suppressing the fire rapidly.

How to Use a Wet Chemical Fire Extinguisher:

  1. Assess the Situation:

Before attempting to use a fire extinguisher, always assess the fire and ensure it is safe to do so. If the fire is spreading rapidly, it is best to evacuate the area and call emergency services.

  1. Activate the Extinguisher:

To activate the wet chemical fire extinguisher, locate the safety pin and pull it out to break the seal. This will enable you to discharge the extinguishing agent.

  1. Aim at the Base:

When using the extinguisher, aim the nozzle at the base of the fire where the burning oil or fat is located. This helps to deliver the wet chemical solution directly onto the fire source for maximum effectiveness.

  1. Sweep Side to Side:

Using a sweeping motion, move the nozzle from side to side, covering the entire area of the fire. This ensures that the wet chemical solution is distributed evenly, effectively cooling the fire and smothering the flames.

  1. Monitor and Evacuate:

Even after using the extinguisher, it is crucial to monitor the area for any signs of re-ignition. If the fire rekindles or you are unable to extinguish it completely, evacuate the area immediately and call for professional help.


Understanding how a wet chemical fire extinguisher works can empower you to respond effectively during kitchen fire emergencies. The cooling effect and chemical reaction of the wet chemical solution provide an efficient means of suppressing fires involving cooking oils and fats. Remember to assess the situation, activate the extinguisher, aim at the base of the fire, sweep side to side, and monitor for re-ignition. Always prioritise safety and call for professional assistance if needed. By equipping yourself with this knowledge, you can contribute to creating a safer environment in your kitchen and beyond.