riser pipe vs pipage

riser pipe and pipage both are nouns.

Word	Noun	Adjective	Verb	Adverb
riser pipe	Yes	No	No	No
pipage	Yes	No	No	No

As nouns, pipage is a hypernym of riser pipe; that is, pipage is a word with a broader meaning than riser pipe:

riser pipe: a vertical pipe in a building
pipage: a long tube made of metal or plastic that is used to carry water or oil or gas etc.

Other hypernyms of riser pipe include pipe, piping.

riser pipe (noun)	pipage (noun)
a vertical pipe in a building	a long tube made of metal or plastic that is used to carry water or oil or gas etc.
	a fee charged for the use of pipes