Plumbing Vents: Code, definitions, specifications of types of vents, wet vents, dry vents, vent distances, terms, definitions.
I constantly get a lot of questions about how far the vent should be located from the actual drain. This is hard for me to answer because I’m not an expert on plumbing codes and from what I know codes can vary from jurisdiction to jusrisdiction, so it’s always best to call up your municipality and find out exactly what applies in your area. Also keep in mind that codes do change from time to time.
But as a general guide you can see what the International Code Council, the International Residential Code, the International Mechanical Code and the National Standard Plumbing Code have to say on this matter. There is also a large library of plumbing and plumbing related articles available from this site as well. Check it out at “InspectAPedia.com”
In the diagram above you can see the minimum and the maximum distances allowed for proper venting for a sink drain. For example, if you find the trap “weir” as shown on the above diagram i.e. the start of the elbow flange, located at the top; the distance from that point to the actual upright vent pipe should be a no less that twice the diameter of the pipe you are currently using; so for a 1.5″ diameter drain pipe that distance should be no less than 3″. The maximum distance from the “weir” should be no more than 3′ 6″ as indicated on the chart.
•PLUMBING VENT DEFINITIONS, TYPES
◦FUNCTION: how plumbing vent piping works
◦DEFINITION of a Plumbing Stack Vent
◦DIFFERENCE Between Soil Stack & Waste Stack
◦DISTANCE: vent piping be located from a plumbing fixture?
◦DRAIN & VENT SIZE & DISTANCES to FIXTURES
◦ROUTING SPECS for PLUMBING VENTS
◦DIRECT VENTED Plumbing Fixtures
◦WET VENTED Plumbing Fixture
◦VENT DISTANCES to BUILDING FEATURES