Boiler and Pressure Vessel engineering

Feb. 04, 2024

Difference Between Tube & Pipe:-

Venkatachalam Ponnusamy

(Petroleum)

(OP)

19 Aug 21 10:52

Dear All,

Refer to the subject can anyone explain what is the Difference between Tube & Pipe in terms of Technical aspect.

I Have observed the following differences Primarily :-
1. Understand that Tube will be available in Circular/Square/Rectangular, where as Pipe will be available in only Circular Form.
2. For 1" Tube the OD is 25.4 mm, whereas 1" Pipe the OD will be 33.4 mm as per B36.10.

Request/Experienced Professionals please provide difference in Technical aspect.

Regards,
Venkat

RE: Difference Between Tube & Pipe:-

LittleInch

(Petroleum)

19 Aug 21 11:26

Tube / pipe can be somewhat interchangable, but in very broad terms,

"Pipe" is available to piping codes and standards and can be virtually any size and is made either from seamless or seamed material in discrete lengths ( usually 12m or so max. It is commonly, though not always, made to ASME B36.10 dimensions, but especially in the former Soviet Union countries can come in different sizes.

"Tube" tends to be drawn as an extruded continuous material, hence limited to relatively small sizes ( max 6-8"?)and used predominantly for instrument tubing or where you need high purity or lack of contamination. It also tends to be as you say, dimensionally precise, so a 25mm NPS "tube is exactly 25mm OD. It can often be reeled and hence have a very long length available or made in discrete lengths.

But as said it's all a bit vague and interchangeable depending on usage and location and you just need to check and confirm what it is you're dealing with. Especially in the smaller sizes.

At that's my interpretation of it. Others may have a different interpretation.

Think you've nailed it already.Tube / pipe can be somewhat interchangable, but in very broad terms,"Pipe" is available to piping codes and standards and can be virtually any size and is made either from seamless or seamed material in discrete lengths ( usually 12m or so max. It is commonly, though not always, made to ASME B36.10 dimensions, but especially in the former Soviet Union countries can come in different sizes."Tube" tends to be drawn as an extruded continuous material, hence limited to relatively small sizes ( max 6-8"?)and used predominantly for instrument tubing or where you need high purity or lack of contamination. It also tends to be as you say, dimensionally precise, so a 25mm NPS "tube is exactly 25mm OD. It can often be reeled and hence have a very long length available or made in discrete lengths.But as said it's all a bit vague and interchangeable depending on usage and location and you just need to check and confirm what it is you're dealing with. Especially in the smaller sizes.At that's my interpretation of it. Others may have a different interpretation.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

RE: Difference Between Tube & Pipe:-

ironic metallurgist

(Materials)

19 Aug 21 14:26
Google also knows a few things

Search past threads on here, this has no doubt been answered many times previously.Google also knows a few things

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."

RE: Difference Between Tube & Pipe:-

LittleInch

(Petroleum)

19 Aug 21 14:30

Such an example is https://www.eng-tips.com/viewthread.cfm?qid=213369

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

RE: Difference Between Tube & Pipe:-

pandithan

(Mechanical)

1 Sep 21 10:15

TUBE-- is used for Heat transfer and OD is controlled
PIPE-- is used for Mass and Heat transfer

RE: Difference Between Tube & Pipe:-

ironic metallurgist

(Materials)

1 Sep 21 13:47
PIPE-- is what supports my mailbox

Either one will suffice when I need more leverage on a stubborn wheel nut

TUBE-- is what makes the bar that holds up my drapesPIPE-- is what supports my mailboxEither one will suffice when I need more leverage on a stubborn wheel nut

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."

RE: Difference Between Tube & Pipe:-

DVWE

(Petroleum)

1 Sep 21 14:09

Quote (ironic metallurgist)
Either one will suffice when I need more leverage on a stubborn wheel nut

Anti-seize

The devil is in the details; she also wears prada.

RE: Difference Between Tube & Pipe:-

EdStainless

(Materials)

Related links:
Machinery 1 Sep 21 14:38
Both can be made in many alloys and either seamless or welded.
Tubing is usually 100%NDT'ed in process and often by two methods while pipe is a much less tightly controlled product both in terms of tolerances and testing. Tubing also usually offers many more options in terms of special testing or special surface conditions. You can also buy tubing that cold drawn to predetermined strength levels.
Some industries (food, personal care products, and pharma) use tube for mass convenience, but this is unusual.
Often mechanical (industrial ) applications will use tube over pipe because the tight tolerances alloy parts to be used as-is with minimal or no machining.
How much does a fiber laser cutting machine cost?
Automatic CNC Machines: Revolutionizing Precision Manufacturing
How to Build a 3D Welding Table
Advantages of a straight 6 over a V8? : r/cars
Difference Between 8BA and 59AB Fatheads
Everything You Need to Know About Pipeline Welding

While tube tends to smaller and lighter than pipe the real difference is the specs.Both can be made in many alloys and either seamless or welded.Tubing is usually 100%NDT'ed in process and often by two methods while pipe is a much less tightly controlled product both in terms of tolerances and testing. Tubing also usually offers many more options in terms of special testing or special surface conditions. You can also buy tubing that cold drawn to predetermined strength levels.Some industries (food, personal care products, and pharma) use tube for mass convenience, but this is unusual.Often mechanical (industrial ) applications will use tube over pipe because the tight tolerances alloy parts to be used as-is with minimal or no machining.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed

RE: Difference Between Tube & Pipe:-

r6155

(Mechanical)

2 Sep 21 00:38

1) @ LittleInch: "so a 25mm NPS "tube is exactly 25mm OD" . NPS = Nominal PIPE size
2) Threads are for PIPES
3) Fittings are for PIPES (flanges, elbows, etc.....)

Regards

RE: Difference Between Tube & Pipe:-

LittleInch

(Petroleum)

2 Sep 21 10:05

You don't often see threaded Tube...

Like I said, the terms are interchangeable....You don't often see threaded Tube...

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

RE: Difference Between Tube & Pipe:-

DriveMeNuts

(Mechanical)

2 Sep 21 11:26

Tube is a generic shape used to describe a long hollow section with undefined material properties.
Tube can be square. Tube can be thick-walled. Tube can be made from porous sponge.
A coffee cup is a tube with a cap on the bottom.

I view pipe as tube with specific characteristics. The two special characteristics of pipe are:
-Pipe is a tube with a continuous cylindrical section.
-Pipe holds and transports fluids, with or without pressure.

Shell and Tube Heat Exchangers use tubes with specific heat transfer properties. Sometimes pipe does the trick as a heat exchanger tube because pipe can transport the fluid, however heat exchanging is not the core purpose of pipe.
A gate or fence can be fabricated from pipe, however structural circular hollow section (not designed for transporting fluids) would be the more correct material to use.

Instrumentation tubing could be referred to as pipe.

RE: Difference Between Tube & Pipe:-

LittleInch

(Petroleum)

2 Sep 21 12:43

Quote (DrivemeNuts)
Instrumentation tubing could be referred to as pipe.

No it isn't (IME). It's referred to as Instrument Tubing.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login

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