Can Branch Vents Span Multiple Floors in Wisconsin?

[FalconTime]

I have an improperly drained kitchen sink and utility sink situation that I am cleaning up (including permits and inspections).

I think that my question is specific to Wisconsin plumbing code. To the best of my knowledge, section 905.5 of the UPC explicitly allows a design like shown below (correct me if I am wrong). However, I can not find any clarity in Wisconsin plumbing code if this is allowed or not. Is the following design allowed in Wisconsin (and UPC, for that matter)?

If it is not allowed, I think could add a vent stack that starts with a wye connection below the washer standpipe sanitary tee. I believe this could be a double wye connection, with the other side serving the utility sink drain per SPS 382.31(4)(b)(1), which states: "The connection of the vent stack to a drain stack shall be at or below the lowest branch drain connection to the drain stack." I know it's not an ideal design, but if the first option doesn't work, it lets me keep the utility sink at a standard height and prevents problems with the standpipe top and trap heights.

Any answers to the bolded question above and the alternative approach if it is not allowed would be greatly appreciated. I haven't posted here before, but this forum has been a great help to me when it came to supply line sizing and a shower install.

 

[Jeff H Young]

I dont know about Wisconcin but nothing wrong with that in UPC code

 

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[FalconTime]

Thanks, it doesn't seem incorrect per any drawings I've seen, but those are almost always UPC.

Anyway, I reworked the base a bit to allow for a pressure test with - might need a long test ball or a 3-4" multisize, we'll see. I'll end up with two cleanouts near each other, but the test ball has to be at the base of the new work and the cleanout needs to be at least 28" from the floor. The standpipe drain and wye will be at 90 degrees from each other, so it won't be blocked. I just flattened the plan to 2D.

I might come back with more questions. Unfortunately, like in Rough-In plumbing/venting help, my AHJ has recently changed policy to not answering most questions before a failed inspection. Maybe the plumbing inspectors association in WI has been making an organized shift on this policy?

 

[Jeff H Young]

it would be preferable to have a full size clean out on the stack. other wise looks good

 

[FalconTime]

Thanks for the heads up on that! It turns out that Wisconsin doesn't have a "one size smaller on stacks" cleanout exception that other codes appear to have. Guess I'll need to keep it 4" up to the reduction to 2". The standpipe should still hit the requirements but my 4.5" of wiggle room is now 0.5".

EDIT: 4" x 4" x 2" PVC DWV Sanitary Street Tee will work perfectly to keep some wiggle room.

 

[Jeff H Young]

we are usually allowed a 3 1/2 inch clean out on 4 inch but never heard of 3 inch allowed Im a differant code. . In reality the 3 inch might be plenty good but we want c/o to match pipe size for basic workmanship. . 21 years Ive never snaked a drain in my house dosent mean I never will

 

[FalconTime]

Late update - looks like I can switch the double wye to a double sanitary tee anyway:

"(i) Double sanitary tees. A cleanout shall be provided immediately above or below a double sanitary tee drain fitting which is installed in a vertical drain pipe of less than 3” in diameter, unless a stack cleanout is provided in accordance with par. (f)."

The only other restrictions on double sanitary tees are related to WCs and kitchen sinks.

The double sanitary tee is greater than 3" in diameter, plus I am providing a stack cleanout anyway. Are there any reasons why I shouldn't use a double sanitary tee to save some height?

 

[FalconTime]

Hmm... looking at the intent of the code, the double sanitary tee restriction on kitchen sinks and WCs is because of high flow and pumping action drain fixtures. While no one should drain the washing machine into the utility sink instead of the standpipe, I suppose someone could. And the drain action of a washing machine seems similar to that of a dishwasher. Maybe it's best practice to use the double wye despite no true requirement to do so. On the other hand, it'll be capped, so there's really no cross flow to be worried about.

I'm probably overthinking this.

EDIT: I'm not certain that a long test ball will make the bend of a sanitary tee, now that I think about it.

 

[John Gayewski]

Try a double fixture fitting. It's more directional than a double tee but also allows for the movement of air freely.

 

[FalconTime]

I looked into those, but do they even make 4x4x4x4 double fixture fittings?

https://catalog.nibco.com/viewitems/pvc-dwv-fittings-2/4835-b-double-fixture-tee-pvc goes up to 3”. Plus, there is a vent prior to the drain connection to the stack.

 

[FalconTime]

I think I’ll stay with the double wye for where I can stick the long test ball down (and serve as a bonus cleanout). Wisconsin's code doesn't look like it forbids using one side of a 4x4x4x4 double sanitary tee as a way to insert a test ball, but it's not as if it says it's allowed either. UPC 706.2 seems to forbid evenly-sized santees outright. I'd rather stick with the more restrictive criteria when it could end up being a judgement call by the AHJ.

 

[John Gayewski]

3" in pvc is as large as they go. There's almost no reason to have 4"drain fittings in a house.

 

[Jeff H Young]

True , rarely a need for 4 inch inside a house unless its got a bunch of w/cs a mansion, 4 toilet homes have 4 inch to first toilet or bathroom . older homes from the first half of 20th century it was common to have 4 inch. on even a single bath home.
but that wont excuse the need to have properly sized clean outs.
Not sure what the issue is on this job at this point? trying to figure out how to get it on test?

 

[FalconTime]

Just if I should use a double wye or a double santee at the level of the test, which is at the same level as the utility sink inlet. It probably doesn’t matter either way. The actual cleanout is provided higher on the stack

 

[Jeff H Young]

double santee might catch and build up debris. double wye would not. You might be able to block off for test bt putting visqueen across the diametor of pipe at the shielded coupling done it many times but also had the visqueen blow out and had to re test. Ive even glued a IPO on the plastic pipe end , after test drain out as much as possible befor busting it out. (can be messy)
These Ideas require some movement at the base also saves on double wye or santee can be a hassel or not just sharing a plumbers trick Ive learned and used many times.