A vertical vent serving two or more fixture branches on the same level is known as a ____ vent.

A vertical vent serving two or more fixture branches on the same level is known as a ____ vent.

• A. Island vent
• B. Stack vent
• C. Common vent
• D. Branch vent

Answer: (C)

Common venting is about using a single vertical vent to serve two or more fixtures that are on the same level. When two or more fixture drains tie together and share that vertical vent, air can enter the drainage system as water flows, which prevents traps from siphoning and helps drains drain smoothly. This arrangement is convenient and code-approved for fixtures on the same floor that are close enough to share one vent rather than each having its own vent line. Other vent types are more specific: an island vent vents a sink located on an island; a branch vent serves a single fixture or a small group connected to a branch line; a stack vent is the vent portion of a vertical stack that vents multiple fixtures along the stack.

Common venting is about using a single vertical vent to serve two or more fixtures that are on the same level. When two or more fixture drains tie together and share that vertical vent, air can enter the drainage system as water flows, which prevents traps from siphoning and helps drains drain smoothly. This arrangement is convenient and code-approved for fixtures on the same floor that are close enough to share one vent rather than each having its own vent line. Other vent types are more specific: an island vent vents a sink located on an island; a branch vent serves a single fixture or a small group connected to a branch line; a stack vent is the vent portion of a vertical stack that vents multiple fixtures along the stack.