What are the differences between pipe, tube, and sanitary tube?

It is fairly common for people to use pipe, tube, and sanitary tube interchangeably. They are similar terms but have different meanings.

What is "pipe"?

Pipe is the workhorse of any set up that doesn't require sanitary standards. It is made based on nominal diameter, that the diameter is approximately that size. For example, 2" pipe has neither an outer nor an inner diameter of 2". Another factor is the schedule of piping, which is the wall thickness with the diameter factored in. A schedule 40 pipe may have similar thicknesses under 8", but can vary greatly above that. Standard combinations of pipe are covered by ASME B36.10 for carbon or alloy steels and ASME B36.19 for stainless steels.

What is "tube"?

Tube refers to round, square, rectangular or oval hollow sections that can be used for pressure equipment, mechanical applications, or general fabrication. Tube measurements need both true dimensions and wall thickness. These specs are more accurate than pipe and a greater level of quality control is implemented during fabrication. 

What is "sanitary tube"?

Sanitary tube refers specifically to the material used in fluid handling installations in industries such as petrochemicals, food & beverage, and pharmaceutical facilities. The cross-section is always round. Different degrees of polish are available depending on the final application. For breweries, wineries, and distilleries, all process lines should be run in sanitary tubing.   

  Pipe Tube Sanitary Tube
Materials
  • Wide Ranges
  • Carbon Steel
  • Low-Alloy Steel
  • Stainless Steel
  • Nickel-Alloy
  • Stainless Steel
  • 304 and 316 are most common
Key Dimensions
  • Nominal Sizing
  • "Approximate"
  • Outer Diameter
  • Inner Diameter
  • Wall Thickness (Schedule)
  • More Accurate Sizing
  • Outside Diameter
  • Wall Thickness
  • True Sizing
  • Outside Diameter
  • Flanges & Clamps are sized based on tube dimensions
Wall Thickness
  • Determined by the Schedule
  • Ratio Base Sizing
  • As the pipe increases of the same Schedule, the width increases
  • Inches
  • Millimetres
  • Tube can be in gauge
  • Inches
  • Millimetres
  • Set based on diameter
Types
  • Round
  • Round
  • Rectangular
  • Square
  • Oval
  • Round
Sizes
  • All sorts
  • More restrictive
  • Up to 6" in one direction not difficult to source
  • 316: 0.5", 0.75"
  • 304/316: 1, 1.5" 2", 3", 4" and 6" are common
  • 304/316: 2.5", 5", 8"+ are available but less common
Connections
  • Plain
  • Beveled
  • Threaded
  • Plain
  • Plain/Weld
Tolerances
  • Set, but loose
  • Material strength is not the largest factor
  • Higher Quality Control
  • Multiple dimensional checks are completed during manufacturing
  • Highest Quality Control
  • Polishing and finish is also inspected
  • Strict weight loading 
Production
  • Plenty of Sizes
  • Highly Automated & Efficient
  • Pipe mills produce quickly
  • More lenghty
  • Typically has more welding and weld removal steps
  • Longest
  • Typically seamless to provide a smooth interior
  • Polishing to a sanitary standard adds costs
Cost
  • Low price per ton
  • Moderate price per ton
  • Depends on the application standard
  • Higher degrees of polishing have higher costs
Delivery
  • Fastest
  • Moderate
  • Longest

 


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