Nominal Pipe Size/Schedule
Nominal Pipe Size (NPS) is a North American set of standard sizes
for pipes used for high or low pressures and temperatures. The name NPS is based on the earlier "Iron Pipe Size" (IPS) system,
and and is closely related to the Schedule (wall thicknesses) of those pipes.
For a given NPS, the outside diameter stays constant and the wall thickness (Schedule) increases
with larger number. The inside diameter will depend upon the pipe wall thickness specified by the schedule
number.
Where applicable, this website uses NPS (Nominal Pipe Size) instead of INCH for the OUTER
DIAMETER (OD) of pipes, flanges, fittings, etc., and this is the only correct way to indicate
the outer dimensions up to and including 12 inches.
Detailed Information
