Remodeling a bathroom with proper venting

[mrrauch]

I'm remodeling a bathroom in NYC (NYC Plumbing Code, 2014 - ie IPC 2009 with amendments). The current layout has a horizontal section as the main vent line for the soil stack - see existing diagram for reference.

We are adding a washer/dryer, and shifting all plumbing to the about 2' or so to the left. Does my proposed diagram look correct?

Thanks in advance! Matt

 

[Terry]

The sequence looks okay depending on the fittings. \
Trap arms that come off a vertical are santees.
The tub trap arm can rise after the vent. It can only grade upward at a 2% slope, or 1/4" per foot.

The dashed line below everything, I hope that's not a vent line for a downstairs.

 

[Sponsor]

 

[mrrauch]

Hi Terry, thanks so much for the feedback. Yes, unfortunately the horizontal dashed line is an existing 4" cast iron vent line for everything downstairs...would you recommend trying to get a vertical one in at the top of the soil stack? We have the walls open so now would be the time to do it, although i gotta say it would be a bit of a pain...

Photo below for reference.

 

[Terry]

I'm not allowed to dump waste down a vent. Is this your home?

 

[mrrauch]

Yes, this is my home, built in 1925. I believe the vertical 4" cast iron vent is original, but can't tell if someone previously cut into and shifted the soil stack so there was a horizontal offset between the main waste line and the main vent. Slightly larger photo below for reference - I highlighted the 4"venting portion of the system with a blue dotted line

 

[Terry]

To me it looks like the waste drops down in the far right corner, picks up the toilet, then the lav and last the tub.
The tub and lav look to be vented and revented at 42" above the floor and then go up.
The lone 4" may be a vent for downstairs.

 

[mrrauch]

Got it. That makes sense Terry. If I understand correctly, the 4" horizontal and vertical portions "past" the wye where the fixtures on this floor tie in is not really doing anything for the fixtures on this floor, but helping the drainage for the next floor down.

 

[Terry]

Yes, and the lav run in 2" could wet vent the toilet and the tub. You could clean that up a bit and get rid of the flat venting on the tub.

 

[mrrauch]

Perfect - thank you again for the help and feedback. I'll discuss with the plumber.

Hope you're staying safe and sound out there in these crazy weeks. All the best, Matt