water riser pipe

riser

riser, 1 1. The vertical face of a stair step. 2. Any upright face, as of a seat, platform, etc. 3. A platform on the stage of a theater or concert hall on which a performer is placed. 4. A water-supply, drainage, gas, steam, or vent pipe which extends vertically, one full story or more, to service several branches or a group of fixtures. 5. An electrical cable which extends vertically, one full story or more, to distribute electrical power to electric panels on the different floors of a building. 6. A duct, which extends vertically, one full story or more, to distribute air to branch ducts on the different floors of a building. 7. A vertical supply pipe for a fire sprinkler system.