What is the difference between tube and pipe?

What is the difference between pipe and tube? In: Mechanical Engineering, Pneumatics [Edit categories] Answer:Answer The primary difference between pipe and tubing is how the size is designated.
Pipe is designated by a "Nominal Pipe Size" based upon the ID (inside diameter) of the most common wall thickness.
Tubing is designated by the measured OD (outside diameter).
For Example: A3/4 inch iron pipe has an OD of1.050 inches, while a3/4 inch steel tube has an OD of0.75 inches.
The Copper industry calls all cooper tubular products "Tubes" but they designate a "Type".
Each type has specified OD and ID dimensions Different answer: The size of a tube is determined by it's OD and the thickness.
The actual OD of a tube is just the same as it's nominal OD.
A certain size of a tube will keep the same OD no mater what the thickness is.
It is true for pipe except that the actual OD is larger than it's nominal OD.
For example, for a1" schedule5s pipe, the actual OD is1.315", the thickness is0.065" and the ID is1.185".
When it's thickness is schedule xxs (0.358"), then it's ID is reduced to0.599" while keeping it's OD.
Furthermore, the actual OD of a pipe is just the same as it's nominal OD when the size is the same as or larger than14" per ASME/ANSI B36.10/19 .
Consequently, both the size of tube and pipe is measured by it's OD and the thickness.
original difference: actually tube is used when we need to transfer heat from its walls and we want this to be happen while in pipes we try to stop the heat transfer such as we use tubes in boilers because we make steam we need to transfer the heat while when we transport steam we use pipes because we wana save heat energy.2: pipe can be thick according to formula d/t >10 while tube will must thin according to this formula.
The Real Difference: Sorry to say; wrong! Pipe and tube is ever so simple.
Pipes are used to transport something, and tubes to construct something; hence, tubes are defined by the od "outside diamater" and wt "wall thickness" (for construction stability), and pipes id inside diamater to allow a calculation for transportation viz., speed, volumes etc.
(od = id +2 * wt) Tamakela The difference is the utilization and nothing else.

Tube is measured by outside diameter, pipe is measured by inside diameter.

Pipe is identified by NB and thickness is defined by Schedule whereas

Tube is identified by OD & its thickness as BWG (Brimingham wire gauge or1/100 inch).

1st difference is that pipes have round cross-section where as tubes could have round, square or other cross-sections.

Pipe sizes are referred mainly by nominal diameter, which is neither ID nor OD but a size standardized by the initial manufacturers. In imperial/US customary system pipe size/dia is designated by NPS followed by a non dimensional number e.g. NPS1, NPS2 NPS12 etc. In SI system pipe size/dia is designated by DN followed by non dimensional number e.g. DN25, DN50 etc. Imperial system numbers are close to inches and SI numbers are close to mm. Different wall thicknesses are designated by Schedules e.g.10,20,40 etc. Pipe of same NPS number but different schedules will have same OD but different IDs depending upon the wall thickness corresponding to the schedule number.

Tube sizes are referred by their OD and wall thickness either in inches or in millimeters e.g. SA-179 tube OD3/4" and wall thickness0.0787" or SA-179 tube OD20 mm and wall thickness2 mm.

I made the answer as simple as I could. Hope this helps to differentiate between tube and pipe.

 

Tube  

1.Lower thickness and higher ductility permits rolling into coils without high differential stress between inside and outside coil.  

2.Specified by outside diameter and actual thickness in mm/inch or wire gauge.  

3.Uniform thickness means less chance of tube failure due to hot spots.  

4.Low roughness factor and lower pressure drop.  

5.Normally used in heat exchangers and coils for heat transfer.  

6.Limitation in sizes.

Pipe  

1.Lower ductility makes it unsuitable to coil. Due to higher moment of inertia larger bending moment is require for the same radius. This means larger residual stress.  

2.Specified by nominal bore and thickness by schedule.  

3.Variation in thickness can cause hot spots and consequent failures.  

4.Higher roughness factor and high pressure drop.  

5.Normally used in straight length for fluid transfer  

6.No limitation.

1) Pipe will be always round but tube can be round, square, hexagonal......
any shape.2) OD of tube is same as its size, but OD of pipe is not same as its size.

according to me, pipe with a diameter less than2" are called tubes

The terms "pipe" and "tube" are almost interchangeable, although minor distinctions exist — generally, a tube has tighter engineering requirements than a pipe.
Both pipe and tube imply a level of rigidity and permanence, whereas a hose is usually portable and flexible.
A tube and pipe may be specified by standard pipe size designations, e.g., nominal pipe size, or by nominal outside or inside diameter and/or wall thickness.

tube designed as it's outer diameter pipe designed as it's inner diameter

I think the word tube is just about the shape , while the "pipe" is about the application.

All of the pipes are tube , but a tube may not mention as a pipe. it could be a shell, liner , rectangular tube , stack,pipe and etc.

There can be many differences, but the key is how they are represented with respect to their dimensions. The Nominal dimensions of Tube are based on outside diameter where as the Nominal dimensions of Pipe are based in Inside diameter.