Making the best of this old house: fixing wet vent

[tomasb]

Here is my situation, and hopefully this drawing makes sense, and you can read it fine (plz, let me know if some info is missing, it's a 3d drawing, so I can rotate it and take a snapshot at any angle).
When we bought the house, the kitchen sink was connected to 2" waste that had a vanity sink connected in the basement below, so that sink in the basement was wet vented.

We are changing kitchen layout, and are moving the main sink, and introducing an island with a secondary sink, and we actually couldn't vent it because of windows, etc, so will be using AAVs.

Primary and secondary kitchen waste pipes I can run between joist, and then I would need to drop and make 90 degree turns to where the waste can go down further. Everywhere the plan is to use 2" pipes, P traps would be 1.5". BTW, the main sink will have a garburator, and a dishwasher hooked up.

A) from secondary sink, to introduce the drop in waste pipe I was thinking to use long sweep, turned/tilted 45, and then to connect to lower horizontal waste pipe using 1/8 turn. OK? not OK? Am I missing something in there?

B) from the main sink, to connect to horizontal waste pipe the idea is to use a long sweep, again, tilted by 45 degrees, and connect that to wye-t laying on its back. Am I missing some gotchas in here? I'm not sure how I feel about that wye-t on its back, considering it's a waste from a main kitchen sink. On the other hand, my space there is super limited. Maybe I'm missing something.

C) The idea is to have some sort of relief vent for kitchen sinks' waste, and hopefully wouldn't need to rely on AAV as much? The worst case scenario: kitchen sink is filled and the garburator is ON speeding up the dump while the dishwasher is dumping its load as well - in that case AAV would kick in. But under normal use, since the sink P trap is 1.5" that is connected to 2" waste line, would it help to have that vent loop, or is it just a wasted effort, and might actually cause more trouble than to solve anything? I do know that max distance before being vented is 8' for 2' pipe with when pitch(drop) is 0.25"/ft.
From my ignorant point of view, the loop would minimize chances of spilling kitchen sinks "goods" into the vent for the sink in the basement, and maybe would decrease chances of opening AAV vents in case there is some pressure drop from some "other activities" in the main waste pipe, like flushing toilets.

Help, please?

Here is the 3d model: kitchen plumbing

 

[Jeff H Young]

I didnt want to read all that you wrote so sorry . but your drawing has this oddball island vent whatchamatalkinbout thing just eliminate that nonsence with a vent on the left and a drain on the right I see no issue that you could be improving on

 

[Sponsor]

 

[tamosius]

<...>

 

[tomasb]

Is this what you are suggesting?
The issue drilling into joist there because I'd be drilling technically in "no-drilling" zone in joists.
Option #1

Option #2: Or is this something like this? Similar as Option 1, just moving basement sink's vent into across joists

Option #3, I think this is the winner:

What's wrong with the drain on the right? As I mentioned -the small sink's drain goes in between joists, then it has to drop bellow the joists.
Or, did you mean that new vertical which seems like a duplicate to existing drain, going to the basement? In which case - is it ok to wet vent the sink in the basement with all the crap going from the kitchen sinks from upstairs?

 

[Tuttles Revenge]

A) from secondary sink, to introduce the drop in waste pipe I was thinking to use long sweep, turned/tilted 45, and then to connect to lower horizontal waste pipe using 1/8 turn. OK? not OK? Am I missing something in there?

The elbow dropping to the 45ell at a 45 would be considered Horizontal to Vertical and only needs to be a Med 90.. not a long sweep.

B) from the main sink, to connect to horizontal waste pipe the idea is to use a long sweep, again, tilted by 45 degrees, and connect that to wye-t laying on its back. Am I missing some gotchas in here? I'm not sure how I feel about that wye-t on its back, considering it's a waste from a main kitchen sink. On the other hand, my space there is super limited. Maybe I'm missing something.

The elbow dropping to the Wye at a 45 would be considered Horizontal to Vertical and only needs to be a Med 90.. not a long sweep. The wye on its back is perfectly fine and is one of several ways drain pipes have combined for decades if not hundreds of years.

C) The idea is to have some sort of relief vent for kitchen sinks' waste, and hopefully wouldn't need to rely on AAV as much? The worst case scenario: kitchen sink is filled and the garburator is ON speeding up the dump while the dishwasher is dumping its load as well - in that case AAV would kick in. But under normal use, since the sink P trap is 1.5" that is connected to 2" waste line, would it help to have that vent loop, or is it just a wasted effort, and might actually cause more trouble than to solve anything? I do know that max distance before being vented is 8' for 2' pipe with when pitch(drop) is 0.25"/ft.
From my ignorant point of view, the loop would minimize chances of spilling kitchen sinks "goods" into the vent for the sink in the basement, and maybe would decrease chances of opening AAV vents in case there is some pressure drop from some "other activities" in the main waste pipe, like flushing toilets.

Vents should not connects under the flood level rim of any fixture. If for some reason your drain clogs, the cross over vent will allow the waste to flood over and into the other vent and likely prevent you from knowing your drain is clogged. There is no plumber here who has ever installed such a loop to provide any evidence that it works or doesn't, but no code allows for this type of connection between vents. The venting from a fixture on a floor below must connect at least 6" above the flood level of the fixture located on the upper floor. The AAV is designed to open when there is negative pressure on the valve. They work fine.

 

[Jeff H Young]

just that wiered connection of vent and waste needs fixing .

 

[Jeff H Young]

pipe on right is a drain disconnect it from the vent period. the drain will go to the 2 sinks and will never reconnect in any way with the vent. option 1 , 2 or 3 are no good

 

[tomasb]

Thanks a lot for coming back with this detail response! To educate myself further, I'd like to ask some follow up questions.

The elbow dropping to the 45ell at a 45 would be considered Horizontal to Vertical and only needs to be a Med 90.. not a long sweep.

Since you used "only needs to be" instead of "has/must be". The way I read/understand it, "only needs to be" would mean "at minimum", while "has/must be" means exactly.
I have space there to install long sweep. and thus, my thinking was - longer means more hydrodynamic, thus better? Easier to snake on longer turns as well?

Is there a reason (e.g., code restrictions, increased risk of clogs due to faster water flow, or other factors) why a long sweep fitting couldn’t be used in a horizontal-to-vertical configuration for a branch that is vented, in this case using AAV?
Edit: British Columbia, Canada code:

2.2.4.3. 90° Elbows
1) Except as permitted in Sentence (2), 90° elbows of 4 inch size or less whose centre-line radius is less than the size of the pipe shall not be used to join 2 soil-or-waste pipes.
2) For sanitary drainage systems of 4 inch size or less, 90° elbows described in Sentence (1) shall only be permitted
a) to change the direction of piping from horizontal to vertical, in the direction of flow,
b) where a trap arm enters a wall, or
c) to connect trap arms as permitted by Sentence 2.5.6.3.(2).

That's all what I could find. I think it's talking about medium sweeps, and where they *can* be used. It does NOT prevent using higher radius ones, so long sweeps should be good?

The elbow dropping to the Wye at a 45 would be considered Horizontal to Vertical and only needs to be a Med 90.. not a long sweep. The wye on its back is perfectly fine and is one of several ways drain pipes have combined for decades if not hundreds of years.

Ok, thanks for confirming, I'll stop worrying about this, considering that I have no space to do anything else in there anyway.

Vents should not connects under the flood level rim of any fixture. If for some reason your drain clogs, the cross over vent will allow the waste to flood over and into the other vent and likely prevent you from knowing your drain is clogged. There is no plumber here who has ever installed such a loop to provide any evidence that it works or doesn't, but no code allows for this type of connection between vents. The venting from a fixture on a floor below must connect at least 6" above the flood level of the fixture located on the upper floor. The AAV is designed to open when there is negative pressure on the valve. They work fine.

Thanks, I'll post updated schematics shortly.

 

[tomasb]

pipe on right is a drain disconnect it from the vent period. the drain will go to the 2 sinks and will never reconnect in any way with the vent. option 1 , 2 or 3 are no good

Thanks, here is the option #4, cut in pieces to make pictures a bit more readable, the last one is the whole thing.
I have updated sweeps as per @Tuttles Revenge comments, thought I haven't found anything in code preventing long sweeps in there in this particular case

Thanks in advance to all of you for comments.
If you are reading this on computer, I've updated 3d model , you can rotate by pressing mouse middle button and drag. Use mouse wheel to zoom in/out.

 

[Tuttles Revenge]

Absolutely NO way you should or need to connect that drain to the vent under the flood level of the upper fixture. If you want to add a form of relief vent for those kitchen drains, it must connect above the flood level. There is no code reason to add the vent, but there's no restriction against it either. It just can Not connect under the flood level.

 

[wwhitney]

When we bought the house, the kitchen sink was connected to 2" waste that had a vanity sink connected in the basement below, so that sink in the basement was wet vented.

That's not a wet vent, it's just an illegal unvented fixture. Since you are contemplating AAVs upstairs, the simplest solution is to vent the downstairs vanity with its own AAV.

Cheers, Wayne

 

[Jeff H Young]

That's not a wet vent, it's just an illegal unvented fixture. Since you are contemplating AAVs upstairs, the simplest solution is to vent the downstairs vanity with its own AAV.

Cheers, Wayne

I see no issue with his plan to tie downstairs lav vent to laundry vent. provided easy acess I wouldnt want to open walls unless I was already doing an extensive amount of drywall . So an AAV might be a good idea . but its that mess Ive mentione 2 or 3 times now that needs fixing and all of us have mentioned it to him

 

[tomasb]

Absolutely NO way you should or need to connect that drain to the vent under the flood level of the upper fixture. If you want to add a form of relief vent for those kitchen drains, it must connect above the flood level. There is no code reason to add the vent, but there's no restriction against it either. It just can Not connect under the flood level.

View attachment 98938

Yes, you explained that already in your previous post. There was an option 4 already. It's too bad my responses have to be "approved", so my responses are delayed a lot.

 

[tomasb]

I see no issue with his plan to tie downstairs lav vent to laundry vent. provided easy acess I wouldnt want to open walls unless I was already doing an extensive amount of drywall . So an AAV might be a good idea .

There is no drywall and all is open at the moment, so it's all good, the plan is for sure is to connect basement lav to laundry vent.

but its that mess Ive mentione 2 or 3 times now that needs fixing and all of us have mentioned it to him

Again, my messages are delayed, the communication is weird. Even as I type this, I have no idea when this is going to get approved, and people might respond into my old messages cause the newest ones are being delayed and are awaiting for moderator approval
I suspect you haven't seen option #4 yet, before writing that?

Edit: oh crap, my option #4 is not even approved! uhhh! So, all of you are responding to old stuff!

@Terry could you, please, "flip the switch" for me to auto approve my responses?

 

[Jeff H Young]

Terry is no longer with us I think family members took over a year plus ago not everyone knows but he is missed
Tomasb well if open walls my opinion is with you to go ahead with the vent for the downstairs lav. and I hope the rest is understood on the unwanted and illegal connection between vent and drain.
I dont know the family of Terry other than a few postings on here , Im hoping its not too much work and that a few bucks comes in for thier efforts if not I also belive and hope they know how much help people get off the site. None of my buisness it could be a lot of work and a net losing operation , Im not assuming anything but thank the Love family for keeping it going!

 

[tomasb]

Terry is no longer with us

I'm in shock, not the news I was expecting to start my day with. Great loss to the community, to say the least, and glad that his legacy keeps on living.

I think family members took over a year plus ago not everyone knows but he is missed
Tomasb well if open walls my opinion is with you to go ahead with the vent for the downstairs lav. and I hope the rest is understood on the unwanted and illegal connection between vent and drain.

Yup.

I dont know the family of Terry other than a few postings on here , Im hoping its not too much work and that a few bucks comes in for thier efforts if not I also belive and hope they know how much help people get off the site.

Absolutely. This is THE forum when it comes to asking for plumbing advice, or even when you google for any question, chances are, you will see this site referenced as one of the top results.

None of my buisness it could be a lot of work and a net losing operation , Im not assuming anything but thank the Love family for keeping it going!

I'm pretty sure they know Terry would love to see this keep on going

 

[Tuttles Revenge]

Thanks a lot for coming back with this detail response! To educate myself further, I'd like to ask some follow up questions.


Since you used "only needs to be" instead of "has/must be". The way I read/understand it, "only needs to be" would mean "at minimum", while "has/must be" means exactly.
I have space there to install long sweep. and thus, my thinking was - longer means more hydrodynamic, thus better? Easier to snake on longer turns as well?

Your understanding is correct. Medium sweeps are the minimum allowed.

Is there a reason (e.g., code restrictions, increased risk of clogs due to faster water flow, or other factors) why a long sweep fitting couldn’t be used in a horizontal-to-vertical configuration for a branch that is vented, in this case using AAV?
Edit: British Columbia, Canada code:

2.2.4.3. 90° Elbows
1) Except as permitted in Sentence (2), 90° elbows of 4 inch size or less whose centre-line radius is less than the size of the pipe shall not be used to join 2 soil-or-waste pipes.
2) For sanitary drainage systems of 4 inch size or less, 90° elbows described in Sentence (1) shall only be permitted
a) to change the direction of piping from horizontal to vertical, in the direction of flow,
b) where a trap arm enters a wall, or
c) to connect trap arms as permitted by Sentence 2.5.6.3.(2).

That's all what I could find. I think it's talking about medium sweeps, and where they *can* be used. It does NOT prevent using higher radius ones, so long sweeps should be good?

Yes, any place that a Med Sweep can be used, a Long Sweep can be used as well. Using a shorter sweep in certain instances has an advantage in saving inches which can be critical for certain applications. But not every place a Long sweep must be used can a Medium sweep be used except for those points that you found in the Canadian code. Their exceptions for elbows at fixture trap arms is common practice in my area, tho not permitted by the UPC which we use..

Ok, thanks for confirming, I'll stop worrying about this, considering that I have no space to do anything else in there anyway.



Thanks, I'll post updated schematics shortly.