Brouillard d'eau | Ai Group

Water Mist Fire Suppression Systems

Water mist systems use micro-droplets to rapidly smother flames and cool the surrounding air.

General Principle of Extinction

Cooling of flames and surrounding gases through droplet evaporation.
Reduction of radiant heat by forming a protective barrier made up of the droplets themselves.
Oxygen displacement through in-situ generation of steam.

Advantages

Using water mist for fire suppression offers many practical benefits:

No toxicity or asphyxiation risk for occupants, unlike gaseous agents,
Environmentally friendly, as water is a natural and non-polluting resource,
Minimal to no damage to sensitive equipment, unlike more invasive systems.

Moreover, water mist systems comply with international standards such as NFPA 750:2015, which defines the design, components, and testing requirements to ensure a reliable and effective installation.

Technical Highlights

Droplet Size Distribution

Smaller droplets are theoretically more effective at extinguishing fires due to their larger evaporative surface area. As a result, NFPA 750 categorizes droplets into three classes:

Class 1: 90% of droplets are smaller than 200 microns
Class 2: 90% of droplets are smaller than 400 microns
Class 3: Droplets larger than 400 microns

Spray Flux Density

Spray flux density refers to the amount of water applied. A sufficient density is critical to extinguish the fire and cool nearby materials.

Discharge Momentum

Discharge momentum reflects the need to direct as many droplets as possible into the flames. Factors such as droplet size, pressure, and spray angle influence the system’s effectiveness.

Each system is custom-designed by our experts to match the specific needs of the site.

Water Mist