Difference between Pipes & Tubes?

See this thread.

Interesting, about every six months or so we seem to get this same question. I am beginning to think there is a training facility or school somewhere that is the origin for this. They must get a new group students and in one of the early classes the instructor asks the students to "define the two terms, Pipe and Tubing."

At least one student in the class does not seem to be able to use "Google" or "search" to find answers.

I found this:

http://www.plumbingmart.com/pipe-and-fitting-dictionary.html

and they turn to CR4.

at least this forum has a name among engineers and engineers-to-be, as a good source of information. it's kind of an honor to be part of this forum where engineers help other engineers.

Flexibility

I still say that if you can stick any portion of your anatomy into it deeper than 1" then it's pipe. Otherwise it's a tube.