Does the schedule number determine the outside diameter of a pipe?

The concept of schedule numbers pertains to the wall thickness of pipe rather than directly determining the outside diameter. While the schedule number is a standardization that indicates the thickness of the pipe walls relative to the nominal pipe size, the outside diameter of pipes, particularly for common materials like carbon steel, is standardized regardless of the schedule number.

For example, in standard piping practices, both a Schedule 40 and a Schedule 80 pipe of the same nominal size (e.g., 2 inches) will have the same outside diameter but differ in wall thickness and pressure ratings. Therefore, the schedule number plays a significant role in defining the mechanical properties and capabilities of the pipe under pressure, but it doesn't dictate the actual outside diameter when looking at pipes of the same nominal size.

This understanding is essential in applications involving piping systems, as it ensures selection of appropriate materials that can withstand required pressure levels while fitting correctly within the system's dimensions.