Tube vs Pipe: Size Chart
Share
Tubes are often measured by their outer diameter (OD). Pipes often measured by Nominal Pipe Size (NPS), a standardized measurement that refers to the approximate inside diameter of a pipe.
In our last blog post, we talked how these measurement systems diverged. Here, we share a quick chart to find equivalent pipes and tubes.
Finding Equivalent Tube Sizes
Although you may expect to find direct equivalents between pipe and tube sizes, this is not always the case. Manufacturers often design tubes and pipes for different purposes, which means there are sometimes variations in their specifications. However, the table below shows the closest tube sizes to standard Schedule 40 pipe sizes based on diameter and wall thickness.
| Nominal Pipe Size (NPS) | Pipe OD | Pipe ID | Pipe Wall Thickness | Closest Tube OD | Closest Tube Wall Thickness | Tube ID |
|---|---|---|---|---|---|---|
| 1/2" | 0.840" | 0.622" | 0.109" | 0.750" | 0.063" | 0.624" |
| 3/4" | 1.050" | 0.824" | 0.113" | 0.750" | 0.125" | 0.500" |
| 1" | 1.315" | 1.049" | 0.133" | 1.000" | 0.125" | 0.750" |
| 1.25" | 1.660" | 1.380" | 0.140" | 1.625" | 0.125" | 1.375" |
| 1.5" | 1.900" | 1.610" | 0.145" | 1.500" | 0.125" | 1.250" |
| 2" | 2.375" | 2.067" | 0.154" | 2.000" | 0.250" | 1.500" |
| 2.5" | 2.875" | 2.469" | 0.203" | 2.500" | 0.125" | 2.250" |
| 3" | 3.500" | 3.068" | 0.216" | 3.000" | 0.125" | 2.750" |
| 4" | 4.500" | 4.026" | 0.237" | 4.000" | 0.250" | 3.500" |
Key Differences Between Pipes and Tubes
-
Wall Thickness: Pipes, particularly in higher schedules, typically have thicker walls than tubes of the same OD. This makes pipes better suited for handling pressure.
-
Outer Diameter (OD): Tube OD is typically an exact measurement, while pipe OD is standardized and varies depending on the NPS and schedule.
-
Application: Pipes are used for transporting fluids or gases, where the ID is critical. Tubes are primarily structural and chosen based on OD and wall thickness.
How to Choose the Right Size for Your Project
When selecting an equivalent tube for a pipe or vice versa, consider the following factors:
-
Application Requirements: Do you need the pressure capacity and fluid-carrying capability of a pipe, or are you looking for the structural strength of a tube?
-
Material: Different materials offer varying levels of strength, corrosion resistance, and compatibility. Be sure to choose the appropriate material for your application.
-
Standards Compliance: Always refer to relevant industry standards, such as ASTM or ASME, to ensure that your selection meets the required safety and performance criteria.
Conclusion
Choosing between pipes and tubes—or finding equivalent sizes—can seem complicated, but understanding the key differences in their measurements and applications can help simplify your decision-making process. The comparison chart provided above is a quick reference guide to help you find the closest equivalent tube sizes to standard Schedule 40 pipes.
If you need further assistance or have any specific questions about your project, feel free to reach out to us. Our team is here to help you select the right materials to ensure the success of your project.