What does ANSI pipe schedule primarily define?

• A. Outer Diameter
• B. Wall Thickness
• C. Material Grade
• D. Corrosion Allowance

Answer: (B)

The ANSI pipe schedule defines how thick the pipe wall is for a given nominal size. For a fixed nominal size, different schedules correspond to different wall thicknesses, which in turn affect the internal bore and the pressure rating. The outer diameter is set by the nominal size and stays essentially the same across schedules, so changing the schedule changes thickness, not the outside dimension. Material grade is specified separately and corrosion allowance is a design margin added or considered later; neither is defined by the pipe schedule. So, the primary purpose of the schedule is to specify wall thickness.