Best way to attach and vent upstairs plumbing?

[Reach4]

I suppose I could put the washer box in the shared wall with the lav. Didn't really think about having the standpipe next to, instead of behind, the washer. Can the shower and WC vents tie in at 6" above the WC flood rim? I assumed it was 6" above the flood rim of the highest fixture.

Above the highest level served by those vents. For a shower and toilet, that is going to be measured from the rim of the bowl.

 

[wwhitney]

I suppose I could put the washer box in the shared wall with the lav. Didn't really think about having the standpipe next to, instead of behind, the washer.

Since this is a second floor laundry, are you taking any measures to reduce the risk of flooding due to a burst washer hose? One advantage of having the laundry box on the sidewall of the laundry closet and maybe half-way forward is that if you leave a couple inches between the machines and the side wall, you can reach the box to turn off the water.

Cheers, Wayne

 

[Sponsor]

 

[Rocketman69]

Above the highest level served by those vents. For a shower and toilet, that is going to be measured from the rim of the bowl.

Gotcha. Thanks for the clarification.

Since this is a second floor laundry, are you taking any measures to reduce the risk of flooding due to a burst washer hose? One advantage of having the laundry box on the sidewall of the laundry closet and maybe half-way forward is that if you leave a couple inches between the machines and the side wall, you can reach the box to turn off the water.

I went with the Sioux Chief OxBox, so I could split them up. Was already planning on having the valves beside the machines for easy access, but was going to put the drain box behind. No big deal keeping them together though. I thought about also having a pan/emergency drain under the machines that would dump into the sump pump pit.

 

[Rocketman69]

I threw together a mock up with some scrap pipe. Anything here I'd need to change? I'm not sure if I can use the heel inlet 90 for the WC vent mounted on a 45 like this, but I didn't see why it would cause any issues.

Kitchen sink, lav, & laundry standpipe have their own vents not pictured.

 

[wwhitney]

UPC wants a combo for the shower takeoff for the configuration shown. Or you could use a san-tee on the 45 like you did the low-heel inlet for the toilet, although then you'd need to approach it from the shower trap differently, using either a 45 or a LT 90 on the flat.

On the other hand, where the kitchen sink comes in, that's a horizontal to vertical, so you don't need a combo, you could use a san-tee. Likewise, the elbow for the laundry/lav can be a medium turn elbow rather than a long turn elbow, since you are going from horizontal to vertical (just for reference, I can't tell which one it is).

Otherwise looks good to me and would work.

I assume the point of having alot of the drains on the vertical 45 like that is to keep the lower 3" wye as high as possible for some reason? If that's the case, you could use a double wye at the height of the upper wye, and combine everything on the horizontal on each side of the double wye. Just an option in case that's desirable for some criterion you haven't mentioned.

[Edit: come to think of it, you don't need that vent labeled 2" stack vent. You just combine the 2" WC vent and the 2" shower vent (which could be 1-1/2") and that's your vent. So instead of a double wye, you could use a double bend, not sure if that's something readily available or just something I see in the catalogs.]

Cheers, Wayne

 

[wwhitney]

Just to flesh out an alternative for you, which keeps everything on the horizontal, hopefully you can decipher my text descriptions. In your handwritten floor plan earlier, I'm calling the top of the page N.

- Run the washer/lav E to hit the kitchen drain coming N, combine with a horizontal 2" combo

- On the left, closet bend, pipe N, long turn 90 to go E, 3x3x2 upright combo for vent, E to double quarter bend.

- On the right, shower trap, upright 2x2x1-1/2" combo for vent, horizontal 2" combo to bring in the kitchen sink/washer/lav, 2" pipe W to 2x3 bushing in the double quarter bend.

If it would fit better, you could swap the horizontal 2" combo on the right for the kitchen sink/washer/lav to a 3" x 2" combo on the left. And note that the shower (2) / kitchen sink (2) / washer (3) and lav (1) make 8 DFUs, which is the maximum allowed on a 2" horizontal drain.

All your vents can be 1-1/2" if desired, except the toilet has to be 2". 1-1/2" vent is good for 8 DFUs.

Cheers, Wayne

 

[Reach4]

Alternate: orange is wye, green is 45.

 

[Rocketman69]

UPC wants a combo for the shower takeoff for the configuration shown.

I'm confused on this one. Where would the combo you're referring to go?

Or you could use a san-tee on the 45 like you did the low-heel inlet for the toilet,

I thought that was what I did?

On the other hand, where the kitchen sink comes in, that's a horizontal to vertical, so you don't need a combo, you could use a san-tee. Likewise, the elbow for the laundry/lav can be a medium turn elbow rather than a long turn elbow, since you are going from horizontal to vertical (just for reference, I can't tell which one it is).

Ah, good. I get confused on the horizontal to vertical vs vertical to horizontal sometimes.

Otherwise looks good to me and would work.

I assume the point of having alot of the drains on the vertical 45 like that is to keep the lower 3" wye as high as possible for some reason? If that's the case, you could use a double wye at the height of the upper wye, and combine everything on the horizontal on each side of the double wye. Just an option in case that's desirable for some criterion you haven't mentioned.

Yeah, exactly. Since this is a small space, I'm trying to keep everything as tight as possible. The stack is coming into the top of the downstairs laundry closet, so I'm trying to hide it as much as I can. I was actually wanting to do exactly what you mentioned, but can't seem to find anyone in town with 3" double wye fittings in stock.

[Edit: come to think of it, you don't need that vent labeled 2" stack vent. You just combine the 2" WC vent and the 2" shower vent (which could be 1-1/2") and that's your vent. So instead of a double wye, you could use a double bend, not sure if that's something readily available or just something I see in the catalogs.]

And this is why I come here. I guess I had it stuck in my head that the stack vent had to be there. Good catch. 3" double ¼ bends aren't any easier to find, but I'm going to hit up the local Ferguson branch this morning to see what they have on the shelf.

 

[Reach4]

I'm confused on this one. Where would the combo you're referring to go?

He is referring to the shower vent, where you have a santee on its back. What you did will work perfectly, and should be allowed by UPC IMO. The argument for requiring the combo seems to be "what if you want to someday convert that vent pipe to a drain line".

 

[Rocketman69]

Just to flesh out an alternative for you, which keeps everything on the horizontal, hopefully you can decipher my text descriptions. In your handwritten floor plan earlier, I'm calling the top of the page N.

Seems like your descriptions are pretty clear. See the following for a few questions:

- Run the washer/lav E to hit the kitchen drain coming N, combine with a horizontal 2" combo

A couple extra joists to drill through, but shouldn't be a problem I suppose.

- On the left, closet bend, pipe N, long turn 90 to go E, 3x3x2 upright combo for vent, E to double quarter bend.

Any reason for the combo vs a san-tee?

- On the right, shower trap, upright 2x2x1-1/2" combo for vent, horizontal 2" combo to bring in the kitchen sink/washer/lav, 2" pipe W to 2x3 bushing in the double quarter bend.

Same question as above, regarding the combo for the shower vent.

If it would fit better, you could swap the horizontal 2" combo on the right for the kitchen sink/washer/lav to a 3" x 2" combo on the left. bend.

Might be tight, but definitely something to consider.

And note that the shower (2) / kitchen sink (2) / washer (3) and lav (1) make 8 DFUs, which is the maximum allowed on a 2" horizontal drain.

Would a dishwasher throw a wrench into the gears here, or is that baked in to the 2 DFUs for the kitchen sink?

All your vents can be 1-1/2" if desired, except the toilet has to be 2". 1-1/2" vent is good for 8 DFUs.

Excellent. Good to know.

 

[Rocketman69]

Alternate: orange is wye, green is 45.

What do I gain here? Is this just to make the trap arm longer prior to the vent?

He is referring to the shower vent, where you have a santee on its back. What you did will work perfectly, and should be allowed by UPC IMO. The argument for requiring the combo seems to be "what if you want to someday convert that vent pipe to a drain line".

Ohhhh....I see. I'm assuming all of the examples I've seen using the Santee on its back must've been using IPC? Thanks for clearing that up.

 

[Reach4]

What do I gain here? Is this just to make the trap arm longer prior to the vent?

Nothing special. I thought that it could be a lower-space alternative to the combo. Lower cost for fittings too; wyes are cheaper than combos. Trap arm 4 inches or longer is plenty, but now that you mention it, I guess that you might be cutting that close.

If reducing some vents to 1.5 would help space, you could look into it. 1.5 seems plenty for most dry vents. https://www.co.lincoln.or.us/sites/default/files/fileattachments/planning_amp_development/page/722/plumbing_guide_2015_-_helpful_hints_residential_construction.pdf has some good info including a minimum vent size table.

Ohhhh....I see. I'm assuming all of the examples I've seen using the Santee on its back must've been using IPC? Thanks for clearing that up.

Those examples probably pre-dated the change in UPC. I don't think current IPC allows that either. I get the impression that some inspectors are still fine with the santee on its back for venting, particularly when space is short. Presume your inspector won't accept it, unless you find out otherwise. See this in the Lincoln County document:

The most common mistake is to
use this san tee in a horizontal
position as a drainage fitting.​

 

[Rocketman69]

Nothing special. I thought that it could be a lower-space alternative to the combo. Lower cost for fittings too; wyes are cheaper than combos. Trap arm 4 inches or longer is plenty, but now that you mention it, I guess that you might be cutting that close.

If reducing some vents to 1.5 would help space, you could look into it. 1.5 seems plenty for most dry vents. https://www.co.lincoln.or.us/sites/default/files/fileattachments/planning_amp_development/page/722/plumbing_guide_2015_-_helpful_hints_residential_construction.pdf has some good info including a minimum vent size table.


Those examples probably pre-dated the change in UPC. I don't think current IPC allows that either. I get the impression that some inspectors are still fine with the santee on its back for venting, particularly when space is short. Presume your inspector won't accept it, unless you find out otherwise. See this in the Lincoln County document:

The most common mistake is to
use this san tee in a horizontal
position as a drainage fitting.​

All good info. Thanks for the reply.

 

[wwhitney]

I think Reach4 covered most of your questions and the whole "san-tee on its back not allowed for venting" thing.

3" double ¼ bends aren't any easier to find, but I'm going to hit up the local Ferguson branch this morning to see what they have on the shelf.

Your fallback confiuration is a little taller and require a little more width (which also seems tight between the toilet on the left and shower on the right): a 3" street quarter bend for the incoming drain on the left, hitting a 3" x 2" combo, with the 3" path vertical and the 2" branch picking up the right side.

That assumes the street bend puts the 3" on the left and the 2" on the right at roughly the correct relative elevations. If the 2" on the right is comparatively too low, you can go with a wye instead of combo. If it's comparatively too high, you can go with a non-street 3" quarter bend.

Would a dishwasher throw a wrench into the gears here, or is that baked in to the 2 DFUs for the kitchen sink?

Only if it is separately trapped with a standpipe, in which case it's another 2 DFU. If it's attached to the sink tailpiece, it's just part of the kitchen sink DFU.

BTW, UPC requires an above the counter air gap on the dishwasher, 2015 UPC 807.3.

Cheers, Wayne

 

[wwhitney]

P.S. I like supplyhouse.com, although it looks like you could get a shipment from them before Tuesday:

https://www.supplyhouse.com/Spears-P327-030-3-PVC-90-Double-Elbow

Cheers, Wayne