Dry Pipe Suppression System

Dry pipe water mist system uses automatic sprinklers attached to a piping system containing compressed air. The bulb of the sprinkler breaks when the ambient temperature reaches its treshold temperature. Pressure drops in the piping network filled with compressed air. Dry pipe valve opens, and releases water to the sprinklers. Dry pipe systems are typically used in spaces subject to freezing.

Source: NFPA 750 Standard on Water MIst Fire Protection Systems

Marioff HI-FOG 3000 Sprinkler