A sizing system of arbitrary numbers that specifies the I.D. (inside diameter) and O.D. (outside diameter) for each diameter pipe. This term is used for steel, wrought iron, and some types of plastic pipe. Also used to describe the strength of some types of plastic pipe.
SCHEDULE, PIPE
Meaning of SCHEDULE, PIPE in English
Environmental engineering English vocabulary. Английский словарь экологического инжиниринга. 2012