In the event of a fire, the system is triggered automatically by a heat alarm or a fire panel output. Heat detection is recommended for kitchens in Approved Document B, and effectively eliminates nuisance activation. Unlike conventional sprinklers, Automist can be stopped manually by pressing a button on its control panel. As Automist uses much less water than a traditional sprinkler system, water damage in the event of activation is minimised.

Once triggered, an under-sink pump drives mains water through the nozzle unit, quickly filling the room volume with a dense fog. Water mist removes heat and displaces oxygen from the fire zone, resulting in fire suppression or extinguishment. The intention is to lower the temperature, lessen the heat and reduce the oxygen concentration to such an extent that combustion can no longer be maintained and therefore reducing damage and maintaining survivable conditions.

Adding water to a kitchen chip pan fire can greatly exacerbate the fire, the same is not true for water mist, as the up draught from the flame and the evaporation of the tiny droplets prevents water from reaching and collecting in the pan.