Feb. 04, 2024
Machinery
You have probably heard the terms pipe and tube used interchangeably, and there's a good chance you aren't exactly sure what the difference is between them. Most people, even experts working in related industries, don't actually know. After all, how different can hollow cylinders get, and who really cares enough to go and look? Well, I had to know...
Even looking on the internet can lead to confusion, as many websites have mistakenly misidentified the real differences between them. Well, since I'm a know-it-all, let me explain as best I can what exactly differentiates tube and pipe. There's a nifty looking infographic you can share at the bottom.
Tubing is generally used for structural purposes and the OD is an important and exact number. Tubing size is specified by OD and WT (wall thickness). The stated OD and measured OD are generally within very close tolerances of each other. Tubing is usually more expensive than pipe due to tighter manufacturing tolerances.
Interestingly, while the stated and measured OD’s of tubing are almost exact in most cases, copper tubing generally has a measured OD that is 1/8” larger than stated OD. As such, maybe it should be called copper pipe. However, stainless steel, aluminum, and steel tubing all have measured and stated OD’s that are exact or within a specified tolerance, usually in the thousandths of an inch (e.g. +/- 0.04").
Pipes are categorized as tubular vessels used in pipeline and piping systems, and commonly transport gases and fluids. They are specified by “Nominal Pipe Size” (NPS) and Schedule (wall thickness). NPS is a size standard established by the American National Standards Institute (ANSI), and should NOT be confused with the various thread standards such as NPT and NPSC.
The manufacturing of Nominal Pipe Sizes from 1/8” to 12” is based on a standardized nominal outside diameter (OD) that is different from the measured OD. NPS pipe 14” and up have measured OD’s that correspond to the nominal size.
The reason many people, including plumbers, engineers, and others, mistakenly believe NPS refers to the ID on smaller pipes is because of how the standard was originally defined. The standardized OD was originally defined so that a pipe with a standardized OD and wall thickness typical of the period when it was established, would have a pipe ID that was approximately equal to the nominal size of the pipe. For example, 3” Schedule 40 NPS has an outside diameter and wall thickness that very roughly gives it an inside diameter of 3”. Regardless of the wall thickness the nominal OD of a pipe will not change.
The long and short is that the NPS was defined so you would know approximately what ID you were working with and could count on the OD never changing. Tubing is defined so you know exactly what OD you are working with and the ID is based on whatever the wall thickness is.
Simply copy this code and paste it into your page to share with others. if you reference this article, please link back here, because you know, we did all the work of explaining it. :-)
<href="https://www.jtcmetals.com/" title="Stainless Steel Cut To Your Specs" img src="https://stainless.s3.amazonaws.com/tube-vs-pipe-the-difference.png" alt="Tube vs Pipe - The Differences Explained in Plain English" width="100%" style="border:none;" />People use the words pipe and tube interchangeably, and they think that both are the same. However, there are significant differences between pipe and tube.
The short answer is.. A PIPE is a round tubular to distribute fluids and gases, designated by a nominal pipe size (NPS or DN) that represents a rough indication of the pipe conveyance capacity; a TUBE is a round, rectangular, squared or oval hollow section measured by outside diameter (OD) and wall thickness (WT), expressed in inches or millimeters.
Pipe is a hollow section with round cross section for the conveyance of products. The products include fluids, gas, pellets, powders and more.
The most important dimensions for a pipe is the outer diameter (OD) together with the wall thickness (WT). OD minus 2 times WT (schedule) determine the inside diameter (ID) of a pipe, which determines the liquid capacity of the pipe.
Examples of actual O.D. and I.D.
Actual outside diameters
1.5/16" (33.4 mm)
2.3/8" (60.3 mm)
3.1/2" (88.9 mm)
4.1/2" (114.3 mm)
12.3/4" (323.9 mm)
14" (355.6 mm)
Actual inside diameters of a 1 inch pipe.
WT. 3,38 mm - I.D. 26,64 mm
WT. 4,55 mm - I.D. 24,30 mm
WT. 6,35 mm - I.D. 20,70 mm
Such as above defined, the inside diameter is determined by the oudside diameter (OD) and wall thickness (WT).
The most important mechanical parameters for pipes are the pressure rating, the yield strength, and the ductility.
The standard combinations of pipe Nominal Pipe Size and Wall Thickness (schedule) are covered by the ASME B36.10 and ASME B36.19 specifications (respectively, carbon and alloy pipes, and stainless steel pipes).
The name TUBE refers to round, square, rectangular and oval hollow sections that are used for pressure equipment, for mechanical applications, and for instrumentation systems.
Tubes are indicated with outer diameter and wall thickness, in inches or in millimeters.
Pipe vs Tube, 10 basic differences
PIPE vs TUBE STEEL PIPE STEEL TUBE Key Dimensions (Pipe and Tube Size Chart) The most important dimensions for a pipe is the outer diameter (OD) together with the wall thickness (WT). OD minus 2 times WT (SCHEDULE) determine the inside diameter (ID) of a pipe, which determines the liquid capacity of the pipe. The NPS does not match the true diameter, it is a rough indication The most important dimensions for a steel tube are the outside diameter (OD) and the wall thickness (WT). These parameters are expressed in inches or millimeters and express the true dimensional value of the hollow section. Wall Thickness The thickness of a steel pipe is designated with a "Schedule" value (the most common are Sch. 40, Sch. STD., Sch. XS, Sch. XXS). Two pipes of different NPS and same schedule have different wall thicknesses in inches or millimeters. The wall thickness of a steel tube is expressed in inches or millimeters. For tubing, the wall thickness is measured also with a gage nomenclature. Types of Pipes and Tubes (Shapes) Round only Round, rectangular, square, oval Production range Extensive (up to 80 inches and above) A narrower range for tubing (up to 5 inches), larger for steel tubes for mechanical applications Tolerances (straightness, dimensions, roundness, etc) and Pipe vs. Tube strength Tolerances are set, but rather loose. Strength is not the major concern. Steel tubes are produced to very strict tolerances. Tubulars undergo several dimensional quality checks, such as straightness, roundness, wall thickness, surface, during the manufacturing process. Mechanical strength is a major concern for tubes. Production Process Pipes are generally made to stock with highly automated and efficient processes, i.e. pipe mills produce on a continuous basis and feed distributors stock around the world. Tubes manufacturing is more lengthy and laborious Delivery time Can be short Generally longer Market price Relatively lower price per ton than steel tubes Higher due to lower mills productivity per hour, and due to the stricter requirements in terms of tolerances and inspections Materials A wide range of materials is available Tubing is available in carbon steel, low alloy, stainless steel, and nickel-alloys; steel tubes for mechanical applications are mostly of carbon steel End Connections The most common are beveled, plain and screwed ends Threaded and grooved ends are available for quicker connections on siteRelated Post(s)
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