
Pipe sizing. What is ID and OD?
Feb 11, 2010· classified by the inner diameter and It’s “schedule” (SCH). TUBING goes by outside diameter and “gauge” (GA). Below are two examples. The first is 2-1/2” tubing, the second is 2-1/2” pipe. See the difference? Even though they both say 2-1/2” The pipe is actually bigger.