Water mist systems

Water mist systems diffuse water through spray nozzles, creating a fine mist/spray.

Water mist systems diffuse water through spray nozzles, creating a fine mist/spray.

This system has found main goals : extinguishing, suppression, control and compensatory measures.

  • Extinguishing; complete and definitive elimination of a fire with open flames or covering fire.
  • Suppression; significant reduction of the heat output thus preventing fire reignition.
  • Control; confining the fire to limit its spread
  • compensatory measures; structural reinforcement and risk mitigation of the fire hazard.

How does it work ?

A mist of water is generated by a pressurizing unit (around 100 bars) and from nozzles with calibrated orifices.

  • deluge system : activated by a fire detection system or manually
  • sprinkler system : activated by a temperature-sensitive element (hot-melt bulb)
  • pre-action system : activated by a fire detection system or manually and by a temperature-sensitive element

What happens during a fire :

  • cooling of hot and fuel gases and pre-wetting
  • cooling of combustion products
  • mitigation of thermal radiation
  • oxygen depletion (local or general) due to water spray

Depending on the nature and constraints of the protection required, two approaches can be considered:

  • total flooding : water mist is scaled to size in order to ensure protection of all, or part of an area
  • object : water mist is directly sprayed on a specific object

When is it used ?

  • Generators – both total flooding and object
  • Transformers
  • Cable tunnels
  • Archive rooms
  • Control rooms, electrical rooms
  • Engine test benches
  • Gas turbines and combustion turbines
  • Hotel rooms, offices, libraries
  • Data centers
  • Road and railway tunnels