What is deluge system for fire protection?

A deluge system is one which uses a detection system that detects exposure to fire or smoke to alert a water sprinkler network which will then flood the affected area with water to douse a fire. They are installed in areas deemed "high-risk" or "high-hazard" such as chemical plants, chemical storage facilities or aircraft hangers. They are one aspect of a firefighting system, which may also use other tools or alarms to ensure people and facilities are protects from fire damage.