Regarding horizontal wet venting, the 2018 IRC P3108.1. says, in part, “Each fixture drain show connect horizontally to the horizontal branch being wet vented OR shall have a dry vent.”
Can the drain of a lavatory downstream of the start of a horizontal wet vent (with additional fixtures entering the horizontal wet vent horizontally further downstream) connect to the horizontal wet vent vertically if it has a dry vent, or does the lavatory drain still need to enter the horizontal wet vent horizontally? The code is unclear, but I’m wondering if a vertical entrance of the lav’s water would interfere with the air gap that needs to be maintained in the upper half of the horizontal drain.
Can the drain of a lavatory downstream of the start of a horizontal wet vent (with additional fixtures entering the horizontal wet vent horizontally further downstream) connect to the horizontal wet vent vertically if it has a dry vent, or does the lavatory drain still need to enter the horizontal wet vent horizontally? The code is unclear, but I’m wondering if a vertical entrance of the lav’s water would interfere with the air gap that needs to be maintained in the upper half of the horizontal drain.
