In pipes with different interior roughness, pipe friction is calculated based on which constant?

In the context of calculating pipe friction in systems with varying interior roughness, the correct choice is the C factor. The C factor, also known as the Hazen-Williams coefficient, is used in the Hazen-Williams equation to represent the influence of pipe material and condition on friction loss. It reflects the roughness of the pipe's interior surface, which affects fluid flow resistance and is crucial for calculating the pressure loss due to friction in water distribution systems.

The C factor allows engineers to account for variations in material and age of the pipe, as smoother pipes will have a higher C factor, indicating lower friction losses, while rougher pipes reduce this factor due to increased turbulence and resistance encountered during fluid flow. This is especially important when selecting materials or assessing the condition of existing pipes in a distribution system.

Understanding the C factor is vital for accurately calculating flow rates, designing efficient systems, and conducting hydraulic analyses in water distribution pipelines.