In plumbing design, what happens when using smaller diameter pipes?

Using smaller diameter pipes leads to increased head loss due to friction. This phenomenon occurs because as water flows through a pipe, it encounters resistance from the pipe walls, and this resistance becomes greater as the diameter of the pipe decreases. The smaller the diameter, the more surface area relative to the volume of water, which amplifies the frictional forces acting on the water as it moves through the pipe. Consequently, a higher proportion of the pressure in the system is consumed to overcome this friction, leading to greater head loss.

In contrast to the other possible outcomes, which would imply a more efficient flow or less resistance, the use of smaller diameter pipes directly results in higher friction losses and therefore increased head loss. Understanding this principle is crucial for plumbing designers, as it affects the overall efficiency of the plumbing system and informs decisions regarding pipe sizing to ensure adequate flow and performance.