Tubes Vs Pipe

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You have probably heard pipe and tube used interchangeably—but are they different? The answer to that question is yes! The biggest difference between pipe and tube is their shape. Pipe will always be round however tube can be round, square or rectangular. Below are several other factors that make pipe and tube different.

The biggest difference between pipe and tube is their shape. Pipe will always be round however tube can be round, square or rectangular.

Pipes:
1. Specification: Defined by Nominal Pipe Size (NPS) and Schedule (wall thickness).

2. Size Standard:

    • NPS from 1/8” to 12” has a nominal outside diameter (OD) that differs from the measured OD.
    • For NPS 14” and above, the nominal size matches the actual OD.

3. Application: Commonly used in pipeline systems for transporting gases and fluids.

4. Wall Thickness: Determined by the Schedule number (e.g., Schedule 40, 80), which affects the inner diameter (ID).

5. Consistency: Standardized globally, allowing for compatibility with fittings like elbows, tees, and couplings.

6. Measurement Approach: Nominal Pipe Size (NPS) provides an approximate ID; the OD is fixed for each NPS.

7. Tolerance: Tolerances are more relaxed, allowing for easy integration with fittings.

8. Material Type: Available in various materials, such as stainless steel, carbon steel, and more.

9. Usage in Industries: Predominantly used in heavy industries (e.g., oil and gas).

10. Cost: Generally more economical due to less stringent manufacturing tolerances.

11. Abrasion Resistance: Thicker schedules (e.g., Schedule 40 to 80) do not necessarily increase resistance; specialized coatings may be required.

12. Conversion Standards: Governed by multiple standards (e.g., ANSI, ASME).

Tubes:

1. Specification: Defined by exact Outer Diameter (OD) and Wall Thickness (WT).

2. Size Standard: The OD is a precise and critical measurement, with the stated and measured OD being nearly identical.

3. Application: Commonly used for structural purposes and pneumatic conveying systems.

4. Wall Thickness: Specified by gauge or wall thickness (e.g., 11 gauge); the larger the gauge number, the thinner the wall.

5. Consistency: Manufactured to tighter tolerances, often with customized sizes and configurations.

6. Measurement Approach: The OD is the key measurement; the ID varies based on wall thickness.

7. Tolerance: Tighter tolerances; dimensions are more precise than for pipes.

8. Material Type: Materials like stainless steel, aluminum, and steel have nearly exact measured and stated ODs; copper tubing may have some differences.

9. Usage in Industries: Widely used in industries like food and plastics.
10. Cost: Generally more expensive due to tighter tolerances and precision.

11. Abrasion Resistance: Not directly applicable as tubes are primarily used for structural purposes.

12. Conversion Standards: Fewer international standards; more custom sizes are possible.

Key Takeaways:

  • Pipes: Measured by nominal size and schedule; standardized for fluid transport and fittings; more economical and widely used in heavy industries.
  • Tubes: Measured by exact OD and wall thickness; used for structural applications; higher precision and tighter tolerances, generally more expensive.
differences between pipes and tubes based on the provided articles:    
Aspect Pipe Tube
Specification Specified by Nominal Pipe Size (NPS) and Schedule (wall thickness). Specified by Outer Diameter (OD) and Wall Thickness (WT).
Size Standard NPS is based on a nominal outside diameter (OD) that differs from the actual OD for sizes 1/8” to 12”. For sizes 14” and above, the NPS matches the OD. The OD is a critical and exact number. Stated OD and measured OD are usually the same or very close.
Application Used mainly in pipeline systems to transport gases and fluids. Commonly used for structural purposes.
Wall Thickness Defined by the Schedule (e.g., Schedule 40, 80). The ID varies depending on the Schedule. Defined by the gauge or wall thickness (e.g., 11 gauge), which is exact.
Consistency Standardized globally for fittings like elbows, tees, and couplings. Can be customized to a wide range of sizes and tolerances.
Measurement Approach Nominal Pipe Size (NPS) gives an approximate ID, while the OD is fixed Outer Diameter (OD) is the primary measurement. The wall thickness determines the ID.
Tolerance Tolerances are more relaxed; pipes are designed to fit with fittings. Tighter tolerances; tubing dimensions are more precise.
Material Type Differences Can vary widely based on the application (e.g., stainless steel, carbon steel). Materials like stainless steel, aluminum, and steel usually have exact measured and stated ODs. Copper tubing may differ.
Usage in Industries Heavy industries (e.g., oil and gas) commonly use pipes. Industries like food and plastics use tubing, especially in pneumatic conveying systems.
Cost Generally more economical due to relaxed tolerances. Usually more expensive due to tighter manufacturing tolerances.
Abrasion Resistance Thicker schedules (e.g., 40 to 80) do not necessarily improve resistance; specialized coatings may be needed. N/A
Conversion Standards Multiple standards (ANSI, ASME, etc.) govern pipe size and specification. Fewer international standards; more custom configurations are possible.
  Key Takeaways:
  • Pipes are measured by nominal sizes, have fixed outer diameters, and are primarily used for fluid transport, following standardized fitting systems.
  • Tubes are measured by exact outer diameters and wall thicknesses, usually come with tighter tolerances, and are often used for structural applications.
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