In a Dry Pipe System, what fills the pipes instead of water?

In a Dry Pipe System, the pipes are filled with pressurized air or nitrogen rather than water. This design is crucial for environments where the risk of freezing exists, such as unheated warehouses or outdoor areas. By using air or nitrogen, the system can prevent water from freezing within the pipes. When a fire is detected and the sprinklers are activated, the pressurized air or nitrogen is released, allowing water from the supply to flow into the pipes and out through the open sprinkler heads.

This approach offers several advantages. It minimizes the risk of pipe bursts due to freezing conditions, which is a significant concern in regions with cold climates. It also allows for quicker activation of the sprinkler system since the air pressure drop can immediately signal the valves to open and let water flow.

The other options provided do not fulfill the role required in a dry pipe system. A water and foam mixture is generally used in specific applications like foam systems for flammable liquid fires but not in dry pipe systems. Carbon dioxide is used in some fire suppression systems, particularly in areas with sensitive equipment, but it is not applicable to dry pipe systems. Liquid nitrogen is not standard in sprinkler systems and has different applications unrelated to fire protection in this context. Thus, the choice of pressurized