Air admittance valves are mechanical devices that take the place of plumbing vents. They're inexpensive, they work, they can reduce the number of plumbing vent penetrations at the roof, they won't get ...

An island sink presents a unique plumbing problem: Like all drains, the sink drain has to be vented to allow air into the pipes to equalize pressure, but how do you connect it to the building’s vent ...