Which of the following systems requires fire personnel to fill it with water?

Dry standpipe systems are designed specifically for use in climates where freezing conditions might occur. Unlike wet standpipe systems, which are always filled with water, dry standpipe systems remain empty until they are needed in an emergency. Fire personnel are responsible for filling these systems with water when responding to a fire or emergency situation. This filling process allows the firefighters to quickly access water through the standpipes for firefighting efforts.

The other types of systems mentioned operate differently. Wet standpipe systems are pre-filled with water, providing immediate access without the need for filling. Class I standpipe systems are designed especially for fire departments and provide 2½-inch hose connections—these systems can be either wet or dry, depending on the configuration. Automatic standpipe systems are usually integrated with fire pump systems and can automatically maintain water levels without needing manual filling. Therefore, the dry standpipe system’s unique operation necessitates the direct involvement of fire personnel for water supply during an incident.