Water mist refers to water that has been converted into small fine droplets or particles through a process known as nebulization. Fogging involves breaking water into extremely small droplets, usually through the use of devices such as nebulizers or sprayers.[1]​.

These devices can generate a mist or spray of water with very fine droplets, which can be as small as micrometers. This technique is used in various applications such as humidification systems, cooling systems, dust control in industry, and also in medical applications such as administering medications through an inhaler.

In the context of fire control, water mist is often used as a firefighting method, as the small droplets have a larger contact surface area with the fire and can absorb heat more effectively. These types of systems are often used in environments where water damage is desired to be minimized, as misting reduces the amount of water used compared to conventional spray methods.[1]​.

In the case of water mist extinguishers, they are designed to fight fires using water that has been converted into small fine droplets through a nebulization process. This type of extinguisher is effective for putting out Class A fires (fires involving common solid materials such as wood, paper, fabric, etc.). Misting water increases the contact surface area with the fire and allows the water to absorb heat more efficiently.[2]​.

Water misting minimizes water damage as less water is used compared to other traditional pressurized water systems.

Water mist is safe for use in fires involving electrical equipment up to certain voltages, as the fine droplets do not conduct electricity in the same way as large amounts of water, mostly used in data centers.[3]​.

They can be used in a variety of environments, including offices, homes and industrial environments, as long as the fire is class A. However, water mist extinguishers are not suitable for class B (flammable liquids) or class C (live electrical equipment) fires. Additionally, the effectiveness of these extinguishers may depend on the specific type of fire and the conditions in which it is found.