Bathroom venting

[Camelot]

Hello, first time poster here. I'm an HVAC professional; just dabbling in a little plumbing for my own bathroom and wanted to clarify a couple code items. I'm in Ohio.

This is a second floor bathroom I'm working on. Lav, tub, w.c. There's also a third floor bath above it, in which the whole bathroom group discharges down a 3" soil stack (6 dfu).

1. Can I tie the 2nd floor toilet into the 3" waste stack (from the third floor) using a sanitary tee? If so, do I need a vent between the toilet and the stack? Or must I use a wye?

2. If he answer is "yes" to the question above, can I use a san tee with a 2" side inlet to drain my lav and tub from the same bathroom group if the lav and tub are vented prior to entering the tee?

3. What horizontal bends can I make in the toilet lateral before the stack, both individually and cumulatively?

I have an ISO drawn, but it assumes I need a circuit vent for the toilet and that I'm discharging the 2" further down the stack with a wye. Thanks for your help.

 

[Terry]

1. Can I tie the 2nd floor toilet into the 3" waste stack (from the third floor) using a sanitary tee? If so, do I need a vent between the toilet and the stack? Or must I use a wye?

You need a vent between the toilet and the stack. With a toilet, either a santee or a wye from the stack.

2. If he answer is "yes" to the question above, can I use a san tee with a 2" side inlet to drain my lav and tub from the same bathroom group if the lav and tub are vented prior to entering the tee?

Yes, the lav can wet vent the tub trap arm, assuming it's run with 2" on the wet portion. The trap arm comes off at the same level that allows venting. No popping up and then over.

3. What horizontal bends can I make in the toilet lateral before the stack, both individually and cumulatively?

Any trap arm can have up to 135 degrees of horizontal change. You can use medium but long sweeps or 45's are better on the horizontal.

 

[Sponsor]

 

[Camelot]

Good call on the wet portion of the tub vent being 2". I swear every house I've remodeled, the plumber used 1-1/2" for that, but maybe the inspector is just letting them get away with it. I checked the table in the Ohio code and sure enough, it's 2" for anything more than 1 dfu on a wet vent. Thanks for your help.