A higher C factor in a pipe indicates what?

A higher C factor in a pipe is indicative of smoother interior surfaces. The C factor, often used in hydraulic calculations, reflects the pipe's resistance to flow; a higher value suggests that there is less friction encountered by the flowing fluid. This smoothness allows water to flow more easily, enhancing efficiency and reducing energy loss due to turbulence and friction.

In practical applications, smoother pipes (which also have a higher C factor) are often more efficient in transporting water, leading to better flow characteristics. The other options don't relate directly to the C factor; for example, the pipe's diameter and its age or condition could affect overall flow capacity and resistance, but they are not what the C factor specifically measures. Therefore, the relationship between a higher C factor and surface smoothness establishes it as the correct answer in the context of flow dynamics in piping systems.