Cookie Consent

Introduction

In industrial process systems, the choice between tubing and pipe is more than a matter of size — it's a critical decision that impacts safety, efficiency, regulatory compliance, and operational integrity. Engineers and procurement specialists must understand the fundamental distinctions between these components to ensure the right fit for their specific applications. This guide explores the core differences between tubing and pipe, their finishes and materials, and when each is best suited for various industries.

What Is the Difference Between Tubing and Pipe?

Tubing is specified by its outside diameter (OD) and wall thickness. It's favored where precise dimensions and tight tolerances are essential.

Pipe, on the other hand, is defined by nominal pipe size (NPS) and schedule (wall thickness), focusing on capacity rather than exact measurements.

While tubing is ideal for precision and higher-purity applications, pipe is typically used for transporting fluids and gases under varying temperatures and pressures.

304L vs. 316L Stainless Steel

Both 304L and 316L stainless steel are fairly corrosion-resistant. However, the significantly higher molybdenum content of 316L makes it superior to 304L in more chemically corrosive applications, particularly involving sulfuric, hydrochloric, acetic, formic, and tartaric acids, acid sulfates, and alkaline chlorides. It is also stronger at higher temperatures compared to 304L.

Tubing Finishes

Our stainless steel tubing is available in several different finishes, follow the guide below to help select which one is ideal for your application.

• Mill Finish tubing is the lowest grade finish we have available, and is the most cost-effective to use in applications that do not require adherence to any kind of sanitation standard. Up to 4″ OD mill finish tubing has a bright annealed outer surface, where larger sizes of this option have an annealed & pickled outer surface.
• 3A polished tubing is the next tier up, intended for applications that require adherence to 3A sanitary standards such as most food-grade processes. 3A tubing has its internal and outer surfaces mechanically polished to <32 Ra roughness, meeting or exceeding ASTM SA249/A249/A269/A270-S2 standards. Tubing with just the outer surface polished is also available, but will not meet 3A standards for process use and is usually just a more aesthetically pleasing alternative to mill finish tubing.
• BPE tubing — short for Bioprocessing Equipment tubing — is the highest-purity variety that we stock, usually constructed with 316L stainless steel and intended for biopharmaceutical and similar applications that require adherence to ASME BPE specs. We offer two different BPE finishes:
• SFT1 tubing has a <32Ra mechanically polished exterior surface similar to that of the 3A polished variety, but its internal surface is mechanically polished to <20Ra roughness, meeting or exceeding ASME BPE SF1 specification standards.
• SFT4 tubing is externally identical to 3A and SFT1 tubing, but its internal surface is electropolished to <15Ra roughness, meeting or exceeding ASME BPE SF4 specification standards.

Pipe Schedules

Schedule pipe is ideal for process applications involving more stresses than mill finish tubing can handle safely, such as elevated temperature, corrosiveness, and/or pressure. We have it available in two thicknesses: Schedule 10 and Schedule 40. Schedule 10 pipe has a thicker wall than the equivalent size OD tubing, thus is sturdier and substantially more resilient under higher temperatures and pressures. Schedule 40 pipe has even thicker walls still than Schedule 10, so it handles corrosion, heat, and pressure substantially better. However, that extra wall thickness makes for heavier weight and a smaller internal diameter with less cross-sectional flow area. It is thus only recommended to use schedule 40 over schedule 10 if the stresses of your application require the step up in durability.

Key Differences in Industrial Applications

Structural and Mechanical Differences

• Tubing typically has a thinner wall and is easier to bend, making it ideal for compact or clean-in-place (CIP) systems.
• Pipe is more robust and generally supports higher pressures, higher temperatures, and longer runs.

Wall thickness and material selection can heavily influence pressure ratings, durability, and system design flexibility.

Sanitary vs. Non-Sanitary Use Cases

• Tubing is the go-to solution for clean, polished finishes required in food, dairy, and biopharmaceutical processes.
• Pipe is best for non-sanitary applications like steam, oil, gas, and compressed air where resilience and pressure rating are critical.

Application Guide — When to Use Tubing or Pipe

Steam Systems

Use stainless steel pipe of the appropriate schedule for high-pressure steam distribution. Tubing may be used for return lines or low-pressure steam condensate.

Food and Beverage Processing

Choose 3A polished tubing to meet USDA and FDA standards, the smooth <32Ra mechanically polished finish reduces contamination risk and allows for easy cleaning. BPE tubing is overkill in these applications.

Biopharmaceutical Manufacturing

Utilize SFT1 or SFT4 BPE tubing with orbital weld compatibility to maintain sterility and meet ASME BPE standards. Which of the two finishes you use will depend on the particular contact medium in your desired application.

Petrochemical and Oil & Gas

Opt for thick stainless steel schedule pipe paired with high-pressure fittings in accordance with the necessary pressure, corrosive, or hazardous material specs.

Selection Tips for Engineers and Planners

Questions to Ask Before Choosing

• What media is being transported?
• Are sanitary conditions required? If so, what kind of standards need to be met?
• What will the operating pressure and temperature be?
• Is space limited or is cleanability a priority?
• Will you need welded, threaded, or compression-type fittings?

By answering these questions, you can select the correct tubing or pipe with help from the above guide and ensure that your process system is safe, compliant, and efficient for your application.

Conclusion

Understanding the fundamental differences between tubing and pipe helps engineers make informed, cost-effective, and regulation-compliant decisions. Tubing is essential for precision and sanitary applications, while pipe remains a durable, pressure-resistant workhorse for heavy-duty industrial systems. When selecting between the two, consider not just the materials, but also the finish, pressure requirements, application environment, and connection types. Matching the right product to the right application ensures optimal system performance and longevity.

FAQs

What is the main difference between pipe and tube?

Pipe sizes are nominal in nature with diameters that are different from their nominal size; tube sizes are defined by their exact outside diameter.

Which is stronger — pipe or tubing?

Pipe generally has thicker walls and can withstand higher pressures, making it stronger in most industrial applications.

Can tubing be used in place of pipe?

Only if durability, compatibility, and regulatory needs are met by tubing's thinner walls — especially in low-pressure or sanitary systems.

What finish is best for sanitary processing applications?

3A or BPE (SFT1/SFT4) finishes are ideal for food, dairy, and biopharmaceutical applications requiring high cleanliness.

When should I choose schedule 10 vs. schedule 40 pipe?

Use Schedule 10 pipe for applications where the stresses would be too high for tubing but not high enough to warrant using schedule 40 pipe.

Does stainless steel grade affect tubing or pipe performance?

Yes — 316L offers superior corrosion resistance and is often used in high-purity or harsh chemical environments over 304L as a result.