Pipe and tube

[C-Bag]

Now THAT is a useful post.

Do you know how many times I've asked plumbers and sales people what IS the difference between pipe and tube? And all I've ever gotten was a blank stare that seemed to convey either "are you stupid?" or "shaddup and buy it". This points out that pipe is a murky quagmire of nonsensical specs and it seems purposely done to only make sense to plumbers. And it doesn't really make sense, they just got used to it.