Help DWV newbie DIY powder room/kitchen

[ColinMcM]

Hi all, I've been following the threads, this is a great resource! I'm remodelling an old house that me and my fiancee bought. Only done plumbing repairs in the past (and plumbing on trees for maple syrup but that's another story)... Made a drawing of plan for the first phase - roughing in a half bath and nearby kitchen sink, tying into a cast iron stack about 17 feet away from toilet. I am aware of the torque wrench and no hub approach for those connections. Main questions are:
1. Is the AAV adequate for this drain unit group (lav, kit sink, WC)?
2. Is the distance to vent OK for the toilet?
3. Is the distance to vertical stack OK for the toilet?
4. Proper use of sanitary tees and combo wyes?
5. Do I need a special fitting at the 90 bend in the long horizontal 3" run?
6. Any problems to note?
7. I want to keep the closet bend as high as possible to minimize the drop over this long run.
8. 1/8 per foot on horizontals for the same reason OK?

 

[Terry]

The kitchen sink can't be part of the bathroom wet vent.
The kitchen get's it's own vent which can tie back in at 42" above the bathroom lav vent. So the kitchen stays downstream.

The toilet 90 can be a 3" medium 90 or a closet 90.

 

[Sponsor]

 

[ColinMcM]

Thank you Terry,
So if I'm using AAVs/Studor vents, would I just have one on the 2" vertical for the lav, which also wet vents the toilet, and another 2" vertical for the kitchen sink with it's own AAV/Studor further downstream? When you say 42" above that makes me think you meant using conventional venting. Is the issue that the wet vent for a WC cannot be integral to the kitchen venting, or that it would be too many units on that 2" wet vent? If I did 3" for that vertical with a double sided sanitary tee branching to the smaller legs for the two sinks, which are back to back on that wall, would that make it acceptable with a 3" AAV/Studor?

 

[wwhitney]

1) Yes, along with what Terry said.
2) Yes, IPC has no limit
3) Yes, no limit after venting
4) Yes
5) Needs to be a long turn 90
6) As Terry said, if the WC is wet vented by the lav, the kitchen sink can't be part of that wet vent.
7) As high as possible is fine, that's what closet bends are for (although in plastic, if I recall it's the same radius as a medium 90). But keeping it high will maximize your fall for a given elevation at the stack connection, so I wouldn't use the term minimize.
8) IPC allows 1/8" per foot on 3"; since I'm used to the UPC which does not, it makes me nervous. Is the 3" of extra fall (over 25') you'd need for 1/4" per foot slope really prohibitive?

A) Yes, that's one option. That would let you put each AAV in its respective sink cabinet. Another option is to combine the vents in the wall at least 6" above both sinks, and then terminate the vent in a single AAV in a ventilated wall box.
B) One AAV can handle 6 DFUs, the issue is just that the wet vent for the WC can be a drain for the lav, but not a drain for the kitchen sink.
C) No, there's no way around keeping the vents separate until 6" above both sinks (and under the IPC each one only needs to be 1-1/2"), then they could combine and go to an AAV.

The use of an AAV requires that elsewhere in the DWV system you have an atmospheric vent that goes through the roof.

Cheers, Wayne

 

[Jeff H Young]

1) Yes, along with what Terry said.
2) Yes, IPC has no limit
3) Yes, no limit after venting
4) Yes
5) Needs to be a long turn 90
6) As Terry said, if the WC is wet vented by the lav, the kitchen sink can't be part of that wet vent.
7) As high as possible is fine, that's what closet bends are for (although in plastic, if I recall it's the same radius as a medium 90). But keeping it high will maximize your fall for a given elevation at the stack connection, so I wouldn't use the term minimize.
8) IPC allows 1/8" per foot on 3"; since I'm used to the UPC which does not, it makes me nervous. Is the 3" of extra fall (over 25') you'd need for 1/4" per foot slope really prohibitive?

A) Yes, that's one option. That would let you put each AAV in its respective sink cabinet. Another option is to combine the vents in the wall at least 6" above both sinks, and then terminate the vent in a single AAV in a ventilated wall box.
B) One AAV can handle 6 DFUs, the issue is just that the wet vent for the WC can be a drain for the lav, but not a drain for the kitchen sink.
C) No, there's no way around keeping the vents separate until 6" above both sinks (and under the IPC each one only needs to be 1-1/2"), then they could combine and go to an AAV.

The use of an AAV requires that elsewhere in the DWV system you have an atmospheric vent that goes through the roof.

Cheers, Wayne

Wayne doesn't IPC allow kitchen sink to be part of a vertical wet vent? Horizontal I don't think so but vertical wet vent I thought was all good?

 

[wwhitney]

If the WC were individually vented, then yes. The IPC allows common venting any two fixtures vertically.

But it stops at two, for three or more they all nee to be bathroom group fixtures. So since the WC is horizontally wet vented by the lav, the kitchen sink needs to be separate. If the kitchen sink were another lav or a shower, it would be OK.

Cheers, Wayne

 

[Jeff H Young]

If the WC were individually vented, then yes. The IPC allows common venting any two fixtures vertically.

But it stops at two, for three or more they all nee to be bathroom group fixtures. So since the WC is horizontally wet vented by the lav, the kitchen sink needs to be separate. If the kitchen sink were another lav or a shower, it would be OK.

Cheers, Wayne[/QUOTE

Thanks Wayne, took another look. Agree that the kitchen sink wouldn't be allowed

 

[ColinMcM]

Thanks guys! You really helped me understand this better. Looks like I can do the 1/4" pf slope on the horizontals just to be safe. I'll do the AAV for the kitchen sink under the cabinet so that it can double as my cleanout there, and use the wall vent option for the lav one since that sink is getting an exposed drain and p-trap.