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a_m_shiha
01-14-2009, 05:04 PM
when one can say this is a tube or say it is a pipe?

what the difference between pipe and tube?is there is universal concept?

ALBERT-ONE-81
03-15-2009, 10:10 PM
HELLO.

PIPES ARE PRODUCED AS FOR A STANDARDIZED RANGE OF DIAMETERS AND A STANDARDIZED RANGE OF WALL THICKNESSES, OTHERWISE A TUBE CAN HAVE EVERY DIAMETER AND EVERY WALL THICKNESS.

ANSI B36.1 GIVE THE DIMENSION FOR PIPING, AND SEE ALSO:
Nominal Pipe Size - Wikipedia, the free encyclopedia ().

ctci
04-05-2009, 05:20 AM
HELLO.

PIPES ARE PRODUCED AS FOR A STANDARDIZED RANGE OF DIAMETERS AND A STANDARDIZED RANGE OF WALL THICKNESSES, OTHERWISE A TUBE CAN HAVE EVERY DIAMETER AND EVERY WALL THICKNESS.

ANSI B36.1 GIVE THE DIMENSION FOR PIPING, AND SEE ALSO:
Nominal Pipe Size - Wikipedia, the free encyclopedia ().


I think you should say Pipe has every diameter and every wall thickness, is more correct, because diameter range of tube normally less than 1 inch and used in air supply system for Instruments and equipments. One never says 10 inch or 20 inch tube. Pipe should be used for process piping system and range from 1/2" to above.

jignesh142
04-05-2009, 06:51 AM
I think you should say Pipe has every diameter and every wall thickness, is more correct, because diameter range of tube normally less than 1 inch and used in air supply system for Instruments and equipments. One never says 10 inch or 20 inch tube. Pipe should be used for process piping system and range from 1/2" to above.

Then why we say "Boiler tubes" instead of "Boiler pipes", if it has diameter larger then 1 inch or the same dia of pipe is also available

ctci
04-24-2009, 04:35 PM
Quote from a book about tubing for reference:
"It is often necessary to choose between tubing and small diameter piping. Where
mechanical damage is not a hazard, tubing offers several advantages. It is faster and
less expensive to form and install tubing than to fit up threaded or socket weld
piping; tubing has less mass and therefore undergoes less stress at connections in
vibrating service; and in most systems it has fewer connections, and therefore fewer
potential leaks. Tubing is not recommended for process service. The most common
services are instrument air, utilities, instrument process leads, and steam tracing."

A.Venugopal
04-24-2009, 06:13 PM
Tubes will have precise OD for fitting in to a corresponding recess, for example a hole of a tube sheet. That is a 2 inch tube will have precisely 50.8 mm OD , pipes will have an outer diameter (for 2" Nominal size , as per ANSI standard 60.3mm diameter ) with an allowed variation as per tolerance. This is the most obvious difference

MartinMas
04-24-2009, 06:41 PM
Dear Sirs, I found this on the net:

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Pipe vs Tube

What's the difference between a pipe and a tube?

More often than not, people guess it has something to do with the quality of the materials, but that's got nothing to do with it. The difference between a pipe and a tube is how they are measured, and ultimately what they are used for.

A pipe is a vessel - a tube is structural.

A pipe is measured ID - a tube is measured OD.

How they are measured... Pipes are measured ID or inside diameter because they are vessels. Tubes are measured OD or outside diameter because they are structural.

Pipes have a consistent ID regardless of wall thickness. In other words, a 1/2" high pressure pipe may need a 2" thick wall, but the ID will still only be 1/2" even tho the OD is 4.5".

Generally speaking, a tube will have a consistent OD and it's ID will change. Engineers see tubes and pipes with different eyes.

A tube is structural.

By having a consistent OD they can vary wall thickness, changing the ID, to increase strength. Because they are consistent OD, they have predictable characteristics.

Again, the difference is simple, it's how they are measured and what their intended uses are.

A.Venugopal
04-25-2009, 06:14 PM
It appears to me that your source had small slip in assuming that pipes ID is constant and OD can vary. Please look in to the dimensions of ANSI B 36.10 pipes : a 1'' NB pipe will have 33.4mm. A 2" NB pipe has 60.3 mm OD and a 3" 88.9 OD. But ID of these pipes will be radically different if you consider schedule 5 or sch10 or sch 20 for these fixed ODs . The usage is : tube will have precise OD, with very narrow tolerance , variable thickness and ID . Pipes also, but for pipes OD is nominal , will have generous tolerance. For tubes also there is a tolerance on OD but that is very small, 0nly 0.5%, some times even as small as plus or minus 0.13 depending on specification.In Industry we use pipes and tubes also as structural members, there is no fixed practice of using tubes only.

Best regards

Venugopal