NPS Pipe Size

NPS Pipe Size is a short form of Nominal Pipe Size and measured in inches (in.). NPS or Nominal Pipe Size is a North American standard which is used to measure Industrial Steel Pipes. These are the standard sizes for Industrial Steel Pipes. NPS is interchangeable with DN which is called as nominal diameter in European region. The manufacturers of Steel Pipes receive the requirements from the buyer as 2inch, 3inch, 4inch, 5inch, 6inch and more. Earlier Each seamless or welded pipe were produced in one thickness which is now called standard (STD). To handle the high pressure of gases and fluids now steel pipes can be produced in thicker walls which are known as XH (Extra Heavy), XXH (Double Extra Heavy), XS (extra strong) and XXS (double extra strong).

At the same time, nominal wall thickness changed to schedule (SCH) for a pipe. Here is the range of Steel Pipe Schedules: SCH 5, SCH 5S, SCH 10, SCH 10S, 20, 30, 40, 40S, 60, 80, 80S, 100, 120, 140, 160, STD, XS and XXS. NPS Pipe Sizes are determined by ASME B36.19 (SS Pipe) and ASME B36.10 (CS Pipe).

Nominal Pipe Thickness and Dimensions as per ASME B36.10

NPS 1/8 Inch to 1 - 1/2 Inch

NPS 2 Inches - 5 Inches

NPS 6 Inches - 11 Inches

NPS 12 Inches - 18 Inches

NPS 20 Inches - 32 Inches

NPS 34 Inches - 48 Inches

NPS and Actual Diameter

NPS is close to OD but different from the Actual Diameter of a pipe. OD or actual diameter value in mm can be differ like 12 Inch (12 NPS) Pipe OD will be 12.75 inches (324 mm).

Compare NPS Pipe Sizes with DN and OD