Laundry Sink + Standpipe Pre-Check

[D C]

As far as I know, this layout should be acceptable, but since I ran out of 2" pipe, I figured I'd check with y'all to see if this looks good.

Pencil at the bottom is floor level. Top of standpipe trap is under 18", standpipe top is 42" AFF, centerline of laundry sink drain is about 17" AFF. The pipe on that trap arm is about 4.25" but can be longer.

Thanks!
Dave

 

[Reach4]

Bottom left 90 should be long sweep.

Alternatively, lower santee becomes a wye, and you have a 45 instead of a 90.

 

[Sponsor]

 

[GReynolds929]

If you’re under UPC you can vertically wet vent the washer through the laundry sink and eliminate the individual vent for the laundry sink. Washer santee needs to be on bottom, stack a 2” tee for the washer under a 2”x1-1/2”x1-1/2” tee for the laundry sink, 1-1-2” pipe through the roof for a vent.

 

[wwhitney]

If you’re under UPC

Michigan is under the IPC/IRC, but you can do the same thing there. They call it common venting (at different levels). In the IRC it's P3107.3.

Cheers, Wayne

 

[D C]

If you’re under UPC you can vertically wet vent the washer through the laundry sink and eliminate the individual vent for the laundry sink. Washer santee needs to be on bottom, stack a 2” tee for the washer under a 2”x1-1/2”x1-1/2” tee for the laundry sink, 1-1-2” pipe through the roof for a vent.

That certainly would make life easier. Like so:

 

[D C]

Bottom left 90 should be long sweep.

Alternatively, lower santee becomes a wye, and you have a 45 instead of a 90.

I have a long sweep if I don't go with a wet vent there. Why would a long sweep be required here for a vertical to horizontal transition?

 

[wwhitney]

I have a long sweep if I don't go with a wet vent there. Why would a long sweep be required here for a vertical to horizontal transition?

Any time the drainage outlet of a 90 degree DWV elbow is horizontal, the elbow is required to be long sweep. So:

horizontal to vertical: quarter bend OK
horizontal to horizontal: long sweep required
vertical to horizontal: long sweep required

Cheers, Wayne

 

[Reach4]

An alternate possibility under IPC:

 

[D C]

Any time the drainage outlet of a 90 degree DWV elbow is horizontal, the elbow is required to be long sweep. So:

horizontal to vertical: quarter bend OK
horizontal to horizontal: long sweep required
vertical to horizontal: long sweep required

Cheers, Wayne

Thanks Wayne. I mentally combined vertical-to-horizontal and horizontal-to-vertical as "gravity = no need for a long-sweep".

...then the engineer in me wonders why one would invent an elbow that isn't long sweep. Smooth transitions are always better in fluid dynamics.

 

[Reach4]

Thanks Wayne. I mentally combined vertical-to-horizontal and horizontal-to-vertical as "gravity = no need for a long-sweep".

...then the engineer in me wonders why one would invent an elbow that isn't long sweep. Smooth transitions are always better in fluid dynamics.

Medium bend is a space saver.

 

[samuellin19]

The long sweep on that vertical to horizontal turn is the part people argue about the most, and Wayne's rule of thumb is the cleanest way I have seen it put: if the outlet of the 90 is horizontal, it has to be long sweep. I had to swap a quarter bend for one on a standpipe years ago after an inspector flagged it, and I have never forgotten it. Your numbers look fine to me by the way. Trap under 18 inches and a 42 inch standpipe are both well inside what you want. Going with the wet vent through the laundry sink is the move though, fewer fittings in the wall and one less run up through the roof. Good luck with the rough in.