Unnecessary Vent?

[nate538]

Hi, I'm remodeling a bathroom and i would like to correct some issues with the current plumbing at the same time. Please excuse my crude drawings hopefully you can understand what's going on.

This is what the plumbing looks like right now, I'm going to add a vent to the tub which is currently un-vented. What i can't figure out is the purpose of the vertical pipe on the left?

Is their anything wrong with eliminating that pipe and venting the way I've drawn here? The only other plumbing in the house is a utility sink in the basement, which also is not vented right now but that will be corrected as well

 

[Reach4]

Your proposal is good.

 

[Sponsor]

 

[nate538]

Thanks for having a look. As far as I can tell the house was built that way which made me believe their must have been a reason for it, but it seems like it was just not well thought out

 

[wwhitney]

I'm going to add a vent to the tub which is currently un-vented.

If the total drop from the tub trap to the 3" bathroom branch (carrying the WC and the lav) is no more than one tub trap diameter, then your tub is currently properly wet vented via the lav.

What i can't figure out is the purpose of the vertical pipe on the left?

It provides a full diameter vent through the roof. Which is something that the UPC requires, but not the IPC. New York State uses the IPC.

Cheers, Wayne

 

[nate538]

If the total drop from the tub trap to the 3" bathroom branch (carrying the WC and the lav) is no more than one tub trap diameter, then your tub is currently properly wet vented via the lav.

I didn't consider that. Right now the tub has a drum trap connected to a side inlet 90, I'll have to see where things land with a standard trap

 

[nate538]

It provides a full diameter vent through the roof. Which is something that the UPC requires, but not the IPC. New York State uses the IPC.

Cheers, Wayne

For the sake of discussion. If a full diameter vent was required, wouldn't that setup still be wrong due to the horizontal section of dry vent before the WC?

 

[wwhitney]

For the sake of discussion. If a full diameter vent was required, wouldn't that setup still be wrong due to the horizontal section of dry vent before the WC?

That's a good question. I would agree it couldn't count as the WC vent, but the WC appears to be properly wet vented via the lav. So if it were just to comply with the UPC's "vent area through the roof" requirement, maybe it's OK.

Cheers, Wayne