"Tube refers to cylindrical, square, rectangular or any shape of hollow material of uniform thickness which is defined by the outside diameter and wall thickness dimensions. (For example 0.375" diameter x 0.062" wall.)
Pipe is round material with specific O.D. and I.D. measurements. The dimensions used in describing pipe refer to its inside diameter and wall thickness. While at one time the inside diameter was a true dimension, over the years the dimension has become "nominal" (in name only) so that when pipe size is referred it is an approximate inside diameter measurement with the thickness described by the term "schedule". (For example: 1-1/2", sch. 40 pipe has an outside diameter of 1.9 inches with a wall thickness of .140"
As it has been said it all depends basically on the industry or discipline dealing with the subject. The use of pipes and tubes as ducts for fluids' conveyance has already been explained.
For heat transfer (eg boilers, etc.), instrumentation (Pitot, Venturi tubes), ordnance (guns), electricity (electron tubes), tubes are generally preferred. Geology has uses for both: tubes (as in caves) and pipes (as in breccia pipes); the same happens with biology. Even computer science uses "pipe" to call the technique of transferring from one program to another during processing.
But all that is in English, in Spanish, for example, when dealing with the transportation of fluids piping is indistinctly called tuber[í]as or ca[ñ]er[í]as.
Hi, would you help me find some textbooks than refers about Pipe Design ( specifically en Thermoelectrical power plants, hydrocarbons transportation, how to choose materials, Dimensions, D, L, Thickness, flow and temperature drop, etc ). if This Text is freeware it would be perfect, if it is not it would help me for create a list of text references to develop the project ( Piping Design Guide ).
well, thank you for your attention and I´ll wait for your answer and suggestions.
In the upstream oil & gas industry, "Tubing" is a pipe less than 4-1/2" OD that goes into an oil or gas well. Anything larger than 4-1/2" that goes into a well is called "Casing". "Pipe" is a generic term for cyclindrical stuff- tubing, casing, conductor, line pipe, the things that the surface people weld together etc..
For simplification and telling immediate difference, forget about the ID or the NB, Generally tubing OD is as it is called out eg 2" is 2" OD (50mm is 50mm OD) while piping OD's are bigger than their call out until you get to 14" (350mm) where the piping OD is as it is called. Tubing at this size is not specified very often so simply put a quick tape across the OD can tell you almost right away pipe or tube.
Hope this helps
