2 story wet vented system questions

[MRBIRD77]

Hi all, 1st post, happy to have found my way here.

I am working out a drain and vent system for two bathrooms in my two story home. I have drawn a simple diagram of what I intend and am hoping I can get some input and the system as a whole as well as some general questions.

For tying the wet vent into the drain behind the 2nd floor WC, I'm unsure what fittings I should use. I propose using a WYE with a long 45 to bring the wet vent at 45 degrees to the top between the closet elbow and the SAN TEE at the stack. I know here I would usually use a SAN TEE with a 45 for a dry vent, but for a wet vent is the WYE acceptable, and is this the correct arrangement to tie it in?

Would it be better to simply continue the waste stack on through the roof instead? venting the 2nd floor WC that way? Additionally, would it be better to tie the first floor WC into the 1st floor dry vent going up to Tee into the stack?

I don't see mention of the location of the WC's in relation to the wet vents in the IPC. I know sometimes the WC is specified to be the last fixture in the system. the arrangement makes that seem impractical and I am wondering if what I have done here is acceptable?

For the 1st floor LAV, and the TUB on the second floor, if I understand correctly, I am allowed 60 Inches to the wet vent tie in which I will be well within. Do you see any issues with this?

Thanks all.

 

[wwhitney]

I am working out a drain and vent system for two bathrooms in my two story home. I have drawn a simple diagram of what I intend and am hoping I can get some input and the system as a whole as well as some general questions.

Your diagram make it look like you have a drop between the upstairs tub trap and where the tub trap arm connects to the lav wet vent. The fall between those two points is limited to one pipe diameter, so you effectively need to have the tub trap at the same elevation as the wet vent. If the little segment between where you say "tub" and where you call out a LT90 is in fact horizontal, not vertical, then the diagram is fine.

Also, the downstairs lav needs a dry vent (or an AAV as I believe you are under the IRC/IPC).

For tying the wet vent into the drain behind the 2nd floor WC, I'm unsure what fittings I should use. I propose using a WYE with a long 45 to bring the wet vent at 45 degrees to the top between the closet elbow and the SAN TEE at the stack. I know here I would usually use a SAN TEE with a 45 for a dry vent, but for a wet vent is the WYE acceptable, and is this the correct arrangement to tie it in?

For a wet vent, the san-tee on its back would be prohibited, as that is not a drainage pattern. Using a wye to connect the wet vent to the WC fixture drain is correct. Typically that wye would be horizontal, i.e. both inlets at 2% slope. You can roll it up 45 degrees if you need to avoid some obstacle (e.g. in the downstairs bathroom, you have the wet vent crossing over the branch drain from upstairs). Rolling it up more would be non-standard and I think allowed but some might disagree.

Would it be better to simply continue the waste stack on through the roof instead? venting the 2nd floor WC that way?

Unless the WC goes to the stack with every other drain tying into the stack below it, the WC is going to be wet vented. Some people prefer to dry vent everything, but wet venting is allowed.

Additionally, would it be better to tie the first floor WC into the 1st floor dry vent going up to Tee into the stack?

Again you can dry vent it or wet vent it as shown.

I don't see mention of the location of the WC's in relation to the wet vents in the IPC. I know sometimes the WC is specified to be the last fixture in the system. the arrangement makes that seem impractical and I am wondering if what I have done here is acceptable?

You have the WC as the downstream-most wet vented fixture in each bathroom. But the IPC would allow a wet vented bathroom fixture to join in downstream of the WC.

For the 1st floor LAV, and the TUB on the second floor, if I understand correctly, I am allowed 60 Inches to the wet vent tie in which I will be well within. Do you see any issues with this?

For the IPC, if the trap size is 1-1/2", then you are allowed 1-1/2" of fall. At the minimum fall rate of 1/4" per foot, that means at most 72" of trap arm length. But the 1st floor lav needs a dry vent, that trap arm has to all be horizontal.

Cheers, Wayne

 

[Sponsor]

 

[MRBIRD77]

Your diagram make it look like you have a drop between the upstairs tub trap and where the tub trap arm connects to the lav wet vent. The fall between those two points is limited to one pipe diameter, so you effectively need to have the tub trap at the same elevation as the wet vent. If the little segment between where you say "tub" and where you call out a LT90 is in fact horizontal, not vertical, then the diagram is fine.

Also, the downstairs lav needs a dry vent (or an AAV as I believe you are under the IRC/IPC).


For a wet vent, the san-tee on its back would be prohibited, as that is not a drainage pattern. Using a wye to connect the wet vent to the WC fixture drain is correct. Typically that wye would be horizontal, i.e. both inlets at 2% slope. You can roll it up 45 degrees if you need to avoid some obstacle (e.g. in the downstairs bathroom, you have the wet vent crossing over the branch drain from upstairs). Rolling it up more would be non-standard and I think allowed but some might disagree.


Unless the WC goes to the stack with every other drain tying into the stack below it, the WC is going to be wet vented. Some people prefer to dry vent everything, but wet venting is allowed.


Again you can dry vent it or wet vent it as shown.


You have the WC as the downstream-most wet vented fixture in each bathroom. But the IPC would allow a wet vented bathroom fixture to join in downstream of the WC.


For the IPC, if the trap size is 1-1/2", then you are allowed 1-1/2" of fall. At the minimum fall rate of 1/4" per foot, that means at most 72" of trap arm length. But the 1st floor lav needs a dry vent, that trap arm has to all be horizontal.

Cheers, Wayne

Thanks Wayne.

The vertical on the tub was just for clarity. I will abide by the vertical drop rule. Also ill have to just run a dry vent for the first floor lav, missed the part about the vertical drop.

Thanks for the input. Glad to see this will work. time to gut and get to work. These two bathrooms are much needed and the start of a long cascade of work to come.

All the best,