What defines a "wet pipe system" in fire sprinklers?

A "wet pipe system" in fire sprinklers is defined by the presence of water stored within the pipes at all times, allowing for immediate discharge when a fire is detected. This design ensures that, upon activation of the sprinkler heads, water flows immediately without delay, which is crucial for effective fire suppression.

Such systems are the most common type used in fire protection due to their simplicity and reliability. The pipes are always filled with water, eliminating the need for additional processes, such as pressurizing air or activating a pump, which can delay the response time in an emergency. This feature makes wet pipe systems particularly effective in areas where the risk of freezing is not a concern.

In contrast, other systems may utilize different mechanisms, such as air-filled pipes or require heat sources, but these do not meet the defining characteristics of a wet pipe system. The immediacy and reliability of water availability when using a wet pipe system make it a preferred choice in many applications, including commercial and industrial settings.