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Category: pipe schedules
Reference Dataset
NPS Commercial Pipe Schedules & Sizes Table
Nominal Pipe Sizes (NPS) dimensions covering outside diameter, Sch 40 and Sch 80 wall thicknesses.
Overview & Scope
Nominal Pipe Size (NPS) defines standard pipe dimensions in commercial piping. Walls are categorized by Schedule numbers, where Sch 40 is standard and Sch 80 is extra-strong.
Technical Sizing Values
The table below specifies outside diameters and wall thicknesses for Schedules 40 and 80 steel pipes.
| Nominal Pipe Size (NPS) | Outside Diameter (mm) | Outside Diameter (in) | Sch 40 Wall Thickness (mm) | Sch 40 Wall Thickness (in) | Sch 80 Wall Thickness (mm) | Sch 80 Wall Thickness (in) |
|---|---|---|---|---|---|---|
| 1/2 in | 21.3 | 0.84 | 2.77 | 0.109 | 3.73 | 0.147 |
| 3/4 in | 26.7 | 1.05 | 2.87 | 0.113 | 3.91 | 0.154 |
| 1 in | 33.4 | 1.315 | 3.38 | 0.133 | 4.55 | 0.179 |
| 1-1/2 in | 48.3 | 1.9 | 3.68 | 0.145 | 5.08 | 0.2 |
| 2 in | 60.3 | 2.375 | 3.91 | 0.154 | 5.54 | 0.218 |
| 3 in | 88.9 | 3.5 | 5.49 | 0.216 | 7.62 | 0.3 |
| 4 in | 114.3 | 4.5 | 6.02 | 0.237 | 8.56 | 0.337 |
Engineering Notes & Best Practices
- •Outside diameter remains constant for a given NPS size; inner diameter decreases as Schedule thickness increases.
- •Schedule numbers relate to the pipe pressure capacity, though exact pressure calculations require Barlow's formula.
- •Fitting joints must be checked to match schedule sizes to ensure constant fluid flow channels.
Dataset Citations & References
ASME B36.10M Welded and Seamless Wrought Steel Pipe
Public domain source and standard catalog reference parameters.