Which pipe material, when new, has a C value of 150?

• A. Polyvinyl Chloride
• B. Cast Iron
• C. Concrete
• D. Steel

Answer: (A)

The main idea here is the Hazen-Williams C factor, which measures the interior roughness and condition of a pipe. A higher C value means the flow experiences less friction loss for the same diameter and length, so the water moves more easily.

Polyvinyl chloride has an exceptionally smooth, non-porous interior and isn’t subject to corrosion or tuberculation like some metals or rough concrete. When new, this smoothness yields a high friction-roughness value, typically around 150, which is higher than the other common materials listed. Cast iron and steel have rougher interiors, especially as they age and corrode, which lowers their C values. Concrete pipe has a comparatively rough interior due to the cement paste and aggregates, also resulting in a lower C than PVC.

So, for a new pipe with the highest C value among these materials, polyvinyl chloride is the best fit.