Couple basic DWV questions

[Ntcarson]

Good morning! I've got a master plumber coming out in a few weeks to help me with my install, but I'd like to be mostly prepared/supplied, so I have a couple questions:
1) In my crawlspace, does the soil stack (where my drains turn down to go underground) need to have a vent straight up from it? If no, is there are rule for distance from a vent? All of my fixtures are well vented, btw.

The next couple questions pertain to the crude drawing below. Please ignore specific fitting types - I know where to use santee, wye, combo, but haven't figured out how to use the drawing program for plumbing yet.
2) In this drawing, do you agree with not wet venting the toilet through the washer/kit drain? The toilet are less than 3' apart.
3) If you would prefer to wet vent the toilet, would you keep the kitchen drain tied into the 3" past the toilet vent, or would you go ahead and tie it into the toilet wet vent? The kitchen is vented already, in the kitchen. I think it would become a no-no if both tied into toilet wet vent.

Thanks, in advance, and sorry for the not great drawing. - Neil

 

[wwhitney]

1) No, vents are for fixture traps, so if every fixture is properly vented, the location of those vents in relation to the building drain is immaterial. At least for low rise buildings.

2/3) Horizontal wet venting is limited to bathroom groups, and so you can't wet vent the WC via a washer drain or a kitchen sink drain. The WC must be vented before the washer drain or kitchen sink drain joins in. The simplest way to wet vent a WC would be bring the properly vented lavatory drain over to join the WC (again before the washer drain or kitchen sink drain come in).

If you want to dry vent the WC, the dry vent takeoff must be vertical (meaning at least 45 degrees above horizontal) and must stay vertical until an elevation at is 6" above the WC flood rim. When that is challenging to comply with, wet venting the WC via the lav is often the way to go.

Cheers, Wayne

 

[Sponsor]

 

[Ntcarson]

1) No, vents are for fixture traps, so if every fixture is properly vented, the location of those vents in relation to the building drain is immaterial. At least for low rise buildings.

2/3) Horizontal wet venting is limited to bathroom groups, and so you can't wet vent the WC via a washer drain or a kitchen sink drain. The WC must be vented before the washer drain or kitchen sink drain joins in. The simplest way to wet vent a WC would be bring the properly vented lavatory drain over to join the WC (again before the washer drain or kitchen sink drain come in).

If you want to dry vent the WC, the dry vent takeoff must be vertical (meaning at least 45 degrees above horizontal) and must stay vertical until an elevation at is 6" above the WC flood rim. When that is challenging to comply with, wet venting the WC via the lav is often the way to go.

Cheers, Wayne

Thanks Wayne!

 

[Ntcarson]

Wayne,
Could I kick the WC vent off the backside, like in the attached image? Please ignore the joint from WC to drain (I still haven't figured out how to show a wye in the drawing program). Basically, kicking off the back of the wye with a reducer and immediate 45, I can avoid ever going horizontal (less than 45) and can completely avoid any WC wet venting. I can then join the washer and kitchen drain downstream a bit.
Thanks!
Neil

 

[wwhitney]

No, that won't work, as you have a small flat section of dry vent, the bottom end of the blue portion of your drawing, plus the straight inlet portion of your wye or combo.

What you can do for the drainage path is Closet Flange - Vertical Fixture Drain - Side Inlet of 3" Wye - Straight Outlet of the 3" Wye, at 45 degrees off plumb - 3" Street 45 to turn horizontal. Then the straight inlet on the 3" wye is your vent takeoff, and it's at 45 degrees off plumb.

That moves your vent a bit towards the closet flange relative to your drawing, so depending on the drop to your horizontal drain, that might not allow the vent to reach a wall before emerging through the floor. Because the vent has to be at least 45 degrees above horizontal.

Cheers, Wayne

 

[wwhitney]

A floor plan would make advising you easier, but the IPC puts no limit on the distance from the closet flange to the WC vent takeoff. So assuming your 3" drain passes under a suitable wall before any other drains (besides the kitchen sink and washer) come in, the simplest option for a dry vent takeoff is this: keep the 2" kitchen sink/washer separate from the 3" WC drain, running parallel to it; when they pass under the wall, use an upright combo for a vertical vent takeoff on the 3" WC drain; then just downstream of that, join your 2" and 3" drains together.

Cheers, Wayne

 

[Ntcarson]

Thank you Wayne - I appreciate you taking the time to ponder this. I've attached another drawing - crude, but shows the area. At Callout 1, I've added a furring wall for W/D plumbing and electrical - If possible, I'd like to vent the toilet up there too. Unfortunately, Callout 2, right along the drain path, is a pocket door with little other room for anything but the door itself. It's pretty tight under that section of the floor (HVAC ducting), but I think I can wye at 45 back towards that wall before I drop the 2 inch pipe from kit/wash into the 3in. If I can handle the straight drop before hitting HVAC duct, I can implement your suggestion from #5.

Again, I really appreciate your time!
Neil

 

[wwhitney]

How about running the WC drain to the left to go under the wall to the left of the WC, then turn down the page?

Cheers, Wayne

 

[Ntcarson]

How about running the WC drain to the left to go under the wall to the left of the WC, then turn down the page?

Cheers, Wayne

I think that will be a good plan - I'll crawl under there tomorrow and take a look. Thank you again, and have a great night!