What is the lowest part of the internal cross section of a pipe called?

What is the lowest part of the internal cross section of a pipe called?

• A. Crown
• B. Base
• C. Invert
• D. Belly

Answer: (C)

The lowest part of the interior of a pipe is called the invert. This is the inside bottom surface that serves as the reference point for elevations and slope planning in gravity-driven piping systems. When designing or inspecting sewer and drainage lines, engineers use the invert elevation to ensure fluids flow properly from one section to the next; the invert is where liquid actually sits and flows from, so it’s the key point for calculating head, capacity, and proper alignment. The crown refers to the top interior surface, not the bottom, and base or belly aren’t standard terms for this specific concept, with belly sometimes used informally to describe a sag along a length rather than the lowest cross-sectional point.

The lowest part of the interior of a pipe is called the invert. This is the inside bottom surface that serves as the reference point for elevations and slope planning in gravity-driven piping systems. When designing or inspecting sewer and drainage lines, engineers use the invert elevation to ensure fluids flow properly from one section to the next; the invert is where liquid actually sits and flows from, so it’s the key point for calculating head, capacity, and proper alignment. The crown refers to the top interior surface, not the bottom, and base or belly aren’t standard terms for this specific concept, with belly sometimes used informally to describe a sag along a length rather than the lowest cross-sectional point.