How does a dry-pipe sprinkler system function when activated?

A dry-pipe sprinkler system is designed to protect areas that may be prone to freezing temperatures. In this system, the pipes that lead to the sprinkler heads are filled with air or nitrogen under pressure, rather than water. This pressurized air keeps the water contained in a storage tank or nearby source.

When the system is activated, typically due to heat from a fire causing a sprinkler head to open, the air pressure within the pipes drops as the air is released. This release of air allows the water-control valve to open, which then permits water to flow from the storage tank into the piping system and out through the activated sprinkler head. Therefore, the functioning of the dry-pipe system hinges on the release of air that activates the water control mechanism, making the selected answer accurate.

Understanding this mechanism is crucial for fire safety personnel, as it highlights the importance of regularly maintaining the air pressure within the system and ensuring that the water-control valve functions properly to respond quickly upon activation.