Which type of sprinkler system always has water in the system?

The wet/automatic sprinkler system is designed to always have water in the pipes. This system is filled with water at all times and only requires the activation of the sprinkler heads to release water during a fire event. When the heat from a fire activates one or more of these sprinkler heads, the pressurized water flows directly from the pipes through the opened heads, taking immediate action to suppress the fire.

The continuous presence of water in a wet sprinkler system is a significant advantage, as it allows for a rapid response to fires, minimizing damage and potentially saving lives. This immediate availability of water is especially critical in scenarios where fast extinguishment of flames is necessary.

In contrast, dry/automatic systems keep the pipes filled with air, releasing water only when the system is activated, which can delay the firefighting response. Deluge systems and pre-action systems are designed for specific applications and typically involve more complex operations where water is not present in the system until certain conditions are met. Hence, the wet/automatic system remains the most straightforward and efficient method for fire suppression due to the constant availability of water.