wet venting

[steve altman]

I have a 3" drain line that services a WC, Lav and Shower. I have a 1.5 inch vent to the roof above the most upstream fixture (lavatory). The shower is next downstream with the WC at the most downstream end of the line. Here is the question, my shower trap arm is 6" above the wet vent/ drain. It connects by elbowing down 90degrees and then turns 90 degrees horizontally to enter the drain. Is this allowed? Normally if the shower trap arm enters the wet vent horizontally, this arrangement would be OK. A plumber friend of mine wasn't sure because of the jog down from the trap.

 

[Teeshot]

pic or line diagram?

 

[linnrg]

vent is to small in UPC world (908.1.1) and it sounds as if the shower is possibly wrong.

 

[mark handler]

Plumbing Code 2018 of Utah
International Plumbing Code 2018 (IPC 2018)

Section 915 Combination Waste and Vent System
915.1 Type of Fixtures; A combination waste and vent system shall not serve fixtures other than floor drains, sinks, lavatories and drinking fountains.

 

[linnrg]

UPC allows based on fixtures that are one or two fixture units (and a shower is 2)

A combination waste and vent is different that a wet vent.

 

[Paul Sweet]

I don't see a prohibition on the "jog down from the trap", but I think it would interfere with air flow in the branch, and require a relief vent where the shower trap arm elbows down 90 degrees.