Using kitchen dry vent to vent shower above?

[Maine Way]

I am considering venting the shower with the vent riser coming from the kitchen (instead of wet-venting it from the a lav in the bathroom group). I would need to connect the shower to the kitchen vent vertically or at a 45 deg min angle until I was 6" above shower curb? Is that how that works?

 

[Reach4]

Depends on what code you are under. If IPC, your vent from the shower trap arm will need to stay vertical until you are 6 inches above the shower flood level. Within 45 degrees of true vertical is considered vertical. Other codes may let your new dry vent go horizontal at a lower level. Check your town or county to see what code they use.

Then you can go vertical or horizontal to where you tie into the kitchen vent. That tie-in point must be at least 6 inches above the flood level of the kitchen sink.

 

[Sponsor]

 

[Maine Way]

Thank you Reach4,

We use UPC 2015 here. But, the concept is the same.

So, I will tie in the kitchen sink at 6" above the sink rim on the first floor, and on the second floor, I'll tie in after the shower trap at 6" above the shower curb. Both can use the same dry vent stack that way.

 

[Reach4]

UPC is more permissive about having horizontal vents for the shower, event below the floor. So the venting fitting is rolled up and can connect to a horizontal pipe that goes over to connect to the vertical vent. If your trap arm is heading toward the wall, there is probably no problem.

 

[Maine Way]

Depends on what code you are under. If IPC, your vent from the shower trap arm will need to stay vertical until you are 6 inches above the shower flood level. Within 45 degrees of true vertical is considered vertical. Other codes may let your new dry vent go horizontal at a lower level. Check your town or county to see what code they use.

Then you can go vertical or horizontal to where you tie into the kitchen vent. That tie-in point must be at least 6 inches above the flood level of the kitchen sink.

Hello Reach4,

This will make the job much easier!

I am stuck on two articles in UPC 2015 to resolve this issue.

Is there an exception to 905.3? I am not prohibited by structural conditions...

And, 905.6 requires symmetrical fitting, but I think this does not apply. It's just for two fixtures when combined into a vertical pipe and before they join riser? It's my first time reading and applying the code and I am trying to get my head around all the technicalities...

905.3 Vent Pipe Rise
Unless prohibited by structural conditions, each vent shall rise vertically to a point not less than 6 inches (152 mm) above the flood-level rim of the fixture served before offsetting horizontally, and where two or more vent pipes converge, each such vent pipe shall rise to a point not less than 6 inches (152 mm) in height above the flood- level rim of the plumbing fixture it serves before being connected to any other vent. Vents less than 6 inches (152 mm) above the flood-level rim of the fixture shall be installed with approved drainage fittings, material, and grade to the drain.

905.6 Common Vertical Pipe
Two fixtures shall be permitted to be served by a common vertical pipe where each such fixture wastes separately into an approved double fitting having inlet openings at the same level.

 

[Reach4]

Vertical here means within 45 degrees of true vertical.

The fitting discussed in 905.5 is frequently referred to here as a double fixture fitting, and the search box above will find many references to that. Sketch up what you would like to do, and post. There are many UPC proficient plumbers here. I am neither.