Would this pass IPC code?

[FloridaArcadia]

I'm doing the plumbing of my house and this is what I came up with. I have a 4" main drain PVC pipe schedule 40 (solid, not foam or cell core) and for each toilet I have a 4" pipe as well (I don't want to do the closet bend my thinking is that 4" to 4" is better so I have a 4" long sweep to the 4" main PVC pipe to the toilet) and from the 4" that goes to the toilet I have a wye with 45 to a 2" that has another branch to the shower and sink, both are 2" as well, I want it that way. On the bathroom sink I have a pipe that goes to the roof an act as a vent. And here comes one of the things that I have no idea if there are limits or not, is there any problem in having the toilet that far off from the vent or is that not a problem? The green dots are where the vents go.

Also on the kitchen island, can I vent it that way? Make a looong connection to the laundry room and reuse the vent from the laundry room? I'm guessing that is a no no and I should do one of those weird loops I've seen and I need to know what to do under the slab before they pour it to make it vent that way.

For the island kitchen I wanted to have a 3" to the main PVC pipe but I think that 2" is good enough? Not sure yet. Thoughts and comments?

ANY comments on this is highly appreciated as we are doing it and calling the inspector and hope it works but if you have any suggestion before that would be great because the only way to understand how this works is by calling the inspector and failing us and lettings us know what we did wrong and fix it.

Thank you so much in advance!

 

[wwhitney]

On bathroom wet venting, what is regulated is the fall of a non-WC trap arm (lav, tub, or shower). The trap arm is from the trap outlet to the vent, which is either the dry vent for the lav (san-tee typically), or a wet vent for the tub or shower. With a wet vent, the trap arm ends at the wye where the fixture drain connects to the lav drain (or other dry vented fixture). In all cases the fall is limited to one pipe diameter. So for an under slab 2" trap for the tub or shower, you can go up to 8' before connecting to the lav drain, if you get the slope at a perfect 1/4" per foot.

In other words, your bathroom wet vents look fine, and the length the WC drain goes before wet venting is not regulated. On the upper (on the page) bathroom, the shower/lav should join the WC before the bathroom branch joins the 4" building drain. You've drawn it as a 4 way junction, but it should be two successive wyes.

For the kitchen island sink, you will need either a loop vent or an AAV. No dry vents under the slab (they have to be at least 6" above the fixture flood rim), so that extra pipe down (the page) to the laundry is not useful. A 2" drain for the kitchen is fine.

One thing you don't show that should be specified is the cleanout locations; I'm not the most knowledgeable on best practices on that. Also, it's not clear to me if the building drain is draining towards the bottom of the page or the top of the page. And what is that symbol on the top of the page just outside the building?

Cheers, Wayne

 

[Sponsor]

 

[Breplum]

3" for a basic house is actually better that 4", in that the carry capability in 3" is more effective.
I am a UPC guy, so no comment on what you have, except to recommend a licensed plumber to do what they are trained to do.
You will most likely regret DIY drains under a slab. There are so many mistakes that can be made, that even an inspector won't take the time to correct.
Use the standard island venting that has proven the test of time unless you are using AAVs

 

[Reach4]

I think the upper bathroom may, or may not, have a problem. If your drawing shows the toilet waste joining the kitchen waste before joining the lavatory drain, which does the wet venting, then it would not be allowed.. If you feed the vented lavatory and shower drainage into the toilet line before the toilet waste joins the kitchen waste, then I think you would probably have proper wet venting.

 

[FloridaArcadia]

On bathroom wet venting, what is regulated is the fall of a non-WC trap arm (lav, tub, or shower). The trap arm is from the trap outlet to the vent, which is either the dry vent for the lav (san-tee typically), or a wet vent for the tub or shower. With a wet vent, the trap arm ends at the wye where the fixture drain connects to the lav drain (or other dry vented fixture). In all cases the fall is limited to one pipe diameter. So for an under slab 2" trap for the tub or shower, you can go up to 8' before connecting to the lav drain, if you get the slope at a perfect 1/4" per foot.

In other words, your bathroom wet vents look fine, and the length the WC drain goes before wet venting is not regulated. On the upper (on the page) bathroom, the shower/lav should join the WC before the bathroom branch joins the 4" building drain. You've drawn it as a 4 way junction, but it should be two successive wyes.

For the kitchen island sink, you will need either a loop vent or an AAV. No dry vents under the slab (they have to be at least 6" above the fixture flood rim), so that extra pipe down (the page) to the laundry is not useful. A 2" drain for the kitchen is fine.

One thing you don't show that should be specified is the cleanout locations; I'm not the most knowledgeable on best practices on that. Also, it's not clear to me if the building drain is draining towards the bottom of the page or the top of the page. And what is that symbol on the top of the page just outside the building?

Cheers, Wayne

Thank you so much for all the information you shared with me! It is SUPER helpful.

A few notes, the top of the drawing is where the septic is located at and the bottom is the higher portion of the system.

The upper bathroom shower/lav would be connected before the WC connects to the 4" main pipe, is just that my drawing skills aren't that great.

Got the idea for the kitchend island, I'll remove the pipe between the island and the laundry, I like the idea of either using a loop or an AAV.

The clean outs are at the top and at the bottom of the drawing, access from both ends of the home, I wanted to add one for the kitchen island but not sure where to put it and if I'll need it, we are very careful but who knows who will end up with this home in the future.

Again, you have no idea how much I appreciate the help and the information you provided to me, I spent until midnight last night trenching the lot to make the trench for the main pipe, today would be the branches to the different fixtures, super excited to start working with the slopes and that!

I almost forgot to mention the weird symbol at the top is the AC outside our home even when I discussed a thousands times that we will use split systems but the architect decided to include it in the drawings anyway!

 

[FloridaArcadia]

3" for a basic house is actually better that 4", in that the carry capability in 3" is more effective.
I am a UPC guy, so no comment on what you have, except to recommend a licensed plumber to do what they are trained to do.
You will most likely regret DIY drains under a slab. There are so many mistakes that can be made, that even an inspector won't take the time to correct.
Use the standard island venting that has proven the test of time unless you are using AAVs

Wow, I would LOVE to understand why a 3" is better than a 4" in carrying the "stuff", honestly. Super curious about this now.

Also, trust me this is all new to me and I'm not doing it because I'm just thinking that I can do it better than anybody else, is just that I asked for quotes around and the only one that came back to me was for $12.000 and I can't pay that kind of money for the plumbing (the quote included all 3 or 4 phases) I really need to do it, it has been a rough battle for us to get to this point and I don't want to stop until we can pay for the plumber because this will delay the next phase, the foundation, a WHOLE lot more so in between not able to pay, difficulty for us to find a contractor to do the job and delays we need to finish this ourselves.

I would use the standard loop on the island, thanks.

Thank you so much for your comments, are really well received and appreciated. Thank you SO much for taking the time to share your thoughts with us

 

[FloridaArcadia]

I think the upper bathroom may, or may not, have a problem. If your drawing shows the toilet waste joining the kitchen waste before joining the lavatory drain, which does the wet venting, then it would not be allowed.. If you feed the vented lavatory and shower drainage into the toilet line before the toilet waste joins the kitchen waste, then I think you would probably have proper wet venting.

The venting for the upper lav/shower is off of the WC connection, not the main drain pipe, my drawing skills aren't great, that's all.

And the top of the drawing is the lowest section of the system and viceversa. I have the septic system at the top of the drawing.

Thanks for taking the time to look at the drawings and offer help, we really appreciate it!

 

[FloridaArcadia]

Just as a reply to myself for future reference I've found the Manning Pipe Flow calculations to determine the optimum pipes for any given flow. SUPER interesting.

Partially Full Pipe Flow Calculator and Equations

Partially Full Pipe Flow Calculator - This engineering calculator determines the Flow within a partially full pipe using the Manning equation.

www.engineersedge.com

 

[Reach4]

I think the solids are the big deal in at toilet soil pipe.