A(n) ________ standpipe system contains piping that is filled with air and does not have a water supply connected to it.

A manual dry standpipe system is designed specifically to contain piping that is filled with air rather than water, and these systems do not have a direct water supply connected to them. This allows for the standpipe to be ready for use without the risk of water freezing in colder climates, making it suitable for certain environments and conditions where water could present operational challenges.

Firefighters can connect hoses to these standpipes and manually charge them with water from a nearby pumper or other water source when needed. The key characteristic of a manual dry system is its reliance on the firefighter's initiative to bring water to the system, rather than having water always present in the pipes. This system is particularly advantageous in situations where a constant state of water readiness is impractical or unnecessary, ensuring that the standpipe remains unobstructed by stagnant water while still being effective as a firefighting tool when required.