How does a Dry-Barrel Hydrant operate in freezing conditions?

A Dry-Barrel Hydrant is designed specifically for use in locations where freezing temperatures are a concern. Its primary feature is that the valve controlling the water flow is located below the frost line, typically underground. This design prevents water from being trapped in the hydrant barrel, which could freeze and render the hydrant inoperable during cold weather. When the hydrant is activated, water flows up from the underground valve, and once it is closed, any residual water within the hydrant drains back down to prevent freezing.

The other options do not accurately describe how a Dry-Barrel Hydrant operates in freezing conditions. For instance, if the hydrant remained partially filled with water, it would be at risk of freezing. Additionally, while it is important to operate hydrants correctly, the requirement to open the hydrant slowly is more about avoiding water hammer or damage rather than a specific operation of dry-barrel hydrants in freezing temperatures. Lastly, while some fire protection systems might utilize heat sources, dry-barrel hydrants are designed to function without the need for any secondary heat source, relying instead on their construction to prevent freezing.