Which type of standpipe relies on the fire department to provide all the water?

A dry standpipe system is designed to rely on the fire department to supply all the water needed for firefighting efforts. In this system, the piping is typically kept dry and does not hold water at all times. Instead, when firefighters arrive, they connect hoses to the standpipe, which allows them to draw water from a local source, like a hydrant, while the fire department's apparatus pumps water into the system.

This setup is particularly useful in areas where it may not be feasible or safe to maintain water in the standpipe due to freezing temperatures or other concerns. Since it does not rely on a constant water supply from the building itself, the fire department's involvement is critical in providing the necessary water pressure and volume to combat fires effectively.

Understanding the characteristics of different types of standpipe systems, such as wet and combined standpipes—which may contain water in their piping systems—or gravity standpipes—relying on elevated tanks to create pressure, further clarifies why the dry standpipe necessitates fire department activation for water delivery.