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Nominal Pipe Size & Pipe Schedules


Tube-Tec Bending can provide pipe bending for a range of pipe sizes and materials. Use the table below for more information about pipe dimensions, NPS, schedules, and weights.

What is Nominal Pipe Size or NPS?

NPS, or nominal pipe size, is the North American set of size standards for pipes that are used for temperatures and pressures of all ranges. The nominal pipe size identifies the size of the diameter of the pipe’s hole with a non-dimensional number. Using the NPS, a pipe is identified by its diameter and then with another non-dimensional number for the pipe’s wall thickness. This non-dimensional number is referred to as the pipe’s schedule. Based on the nominal pipe size and the schedule of the pipe, the pipe’s thickness can be obtained from conversion tables like the one below. 

What is a Pipe schedule?

For pipes of all sizes, the outer diameter remains fairly consistent. Variation in wall thickness affects the ID, or inner diameters, of pipes. Schedule numbers for pipes reference the thickness of the wall on different size pipes. As the schedule number increases, the thicker the wall of the pipe becomes. The schedule number on a pipe increases as the pipe’s wall size increases, and the wall thickness changes based on a Nominal Pipe Size chart. A basic conversion chart can explain the relationship between schedules, pipe sizes, and wall thicknesses. The most common pipe schedules are schedule 40 and schedule 80.

 Pipe Schedule & Weight Information

  Schedule 40Schedule 80
Nominal Pipe Size Outside Diameter Wall Thick. Wt. per Ft. Wall Thick. Weight Per Ft.
1/8 .405 .068 .245 .095 .315
1/4 .540 .088 .425 .119 .535
3/8 .675 .091 .568 .126 .739
1/2 .840 .109 .851 .147 1.088
3/4 1.050 .113 1.131 .154 1.474
1 1.315 .133 1.679 .179 2.172
1-1/4 1.660 .140 2.273 .191 2.997
1-1/2 1.900 .145 2.718 .200 3.631
2 2.375 .154 3.653 .218 5.022
2-1/2 2.875 .203 5.793 .275 7.661
3 3.500 .216 7.576 .300 10.250
3-1/2 4.000 .226 9.109 .318 12.510
4 4.500 .237 10.790 .337 14.980
5 5.563 .258 14.620 .375 20.780
6 6.625 .280 18.970 .432 28.570
8 8.625 .322 28.550 .500 43.390
10 10.750 .365 40.480 .500 54.740
12 12.750 .375 49.560 .500 65.420

 nominal pipe size and pipe dimensions

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