In dry sprinkler systems, what is the primary gas in the pipes?

In dry sprinkler systems, the primary gas in the pipes is pressurized air. These systems are specifically designed to prevent water from sitting in the pipes and potentially freezing, which could impair their function in cold environments. Instead, the system is filled with air or inert gas, which keeps the valve closed until a fire event occurs.

When heat from a fire activates the sprinkler heads, the pressurized air in the pipes allows a valve to open, releasing the water stored in a separate tank or reservoir. This design is critical in ensuring the reliability of the system in lower temperatures, as it protects the wet sprinkler components from freezing and maintains proper system operation.

While water is essential for sprinkler operation during discharge, it is not present in the pipes when the system is inactive. Carbon dioxide and nitrogen can both be used in various applications, but pressurized air is the standard for dry systems, allowing them to function correctly during a fire emergency.