Difference Between Tube and Pipe
The two objects pipe and tube are so similar that they almost seem the same. The difference between them is their size. While the term pipe is more of a global term, tube is more a term that is used in the US.
A pipe is usually specified by the inside diameter of the body unlike the tube whose dimensions depend on the outer diameter, inner diameter and the thickness of the wall. The word pipe is used a plural noun when it is used for irrigation purpose. While pipes that are measured in (iron pipe size) are used for plumbing, copper tubes that have measurement based on average diameter are also used for the same purpose as well.
While pipes come with rigid joints tubes are found in both hard tempered rigid joints and soft tempered rolls. The size of a tube does not depend on the copper temper as it can be joined flexibly or rigidly. Thus it is clear that nature of the joint does not affect the size.
There are variable thickness between a pipe and a tube. The thickness of the wall of a tube may be different from that of a water pipe. There are four types of tubes with different thickness, like the DWV type which by far has the thinnest wall, M type tube that has less thin wall, type L that has a thick wall and K type which has the thickest wall of all of them. These are known and relevant data for the plumber who also knows well that the wall thickness of a tube or pipe do not affect the size of a pipe or a tube.