Townhouse Sanitary & Vent

[Loumolito]

I am working on a 4-story "stacked" townhouse plumbing design. For those who aren't familiar there are two, 2-story towhouses stacked on top of each other.

My background in plumbing mostly commercial. I am stumped on how bathroom groups on each floor (not stacked) connect to each other without a main stack & stack vent.

I cannot find one wall on each floor to line up.

See link to my riser diagram. It looks very unconventional to me. I'm used to seeing a stack vent on the top of each stack.

Any thoughts? Does this look right.

 

[trashcanman]

From 2006 IPC: 903.2 Vent stack required. A vent stack shall be required fbr
every drainage stack that has five branch intervals or more.

Looks like you do need a vent stack at the 1st elbow down.

Explain to the Architect that it is NOT good practice to route sanitary waste over someone's kitchen, bedroom, etc. It could be a noise problem and worse if it leaks. Send it to the Architect in writing as a CYA note.

Get the plumbing walls to line up.

 

[Loumolito]

I don't have 5 or more branch intervals so why would IPC 903.2 apply?

Looks like you are a commercial engineer also. If we would design the architecture, the homes would never sell. Residential plumbers do what it takes to make it work. After all, how many drainage & vent systems don't work? In my 15 years as a designer, I can't tell you of any complaints (just HVAC problems).

 

[kbs]

Local plumbing codes all differ slightly. If this was in my jurisdiction, the answers to the two balloons in the drawing are:
1. Yes, it's permitted
2. No, you don't require a vent at that location
However, the shower on the top floor is not vented to code.