What is the characteristic of a dry standpipe system?

A dry standpipe system is specifically designed to be empty of water until needed, which means it can operate without a direct water supply already being available in the system. This type of system is typically used in buildings where a constant water supply is either impractical or would pose a risk, like in some high-rise structures.

In a dry standpipe system, firefighters or trained personnel can connect hoses and use their water supply, usually brought in by fire apparatus, to fill the standpipe as they fight a fire. This characteristic allows it to be operational even if there is no pre-established water supply in the standpipe, distinguishing it from other systems that might always have water in them.

The other characteristics of standpipe systems do not apply to dry standpipes; they do not require a constant water source, and they are typically not connected to hydrants but rely on external water sources when needed.