Venting Bathroom and Laundry Rooms - Unnecessary Vents?

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Scott Yackley

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Are the vent lines questioned in the picture necessary? Was thinking that these fixtures are all vented thru the main stack or wet vented from other fixtures.
 

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Reach4

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Shower could be wet vented by making the lav drain go horizontal on the same level as the shower trap arm. I think that would be true for UPC and IPC.
 

Terry

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If the shower arm was on the same plane as the line to the lav, then the lav would vent. But since you raised that line up with a 90 bend, it now needs it's own vent.

The washer should keep it's vent.

The laundry tray can vent using the main vent stack.

The toilet should not drop into a santee. The waste that lands into a tee on it's back will spread both ways.
 

Scott Yackley

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Thanks for the feedback. Here is an updated diagram. The toilet drops into a 4"x3" closet bend. Does the toilet drain still need a vent line, or can it vent to main vent stack?
 

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Reach4

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I think you need that toilet vent. If the tub and shower drainage joined the toilet flow before the big pipe, that would wet vent the toilet. But with your layout, the separate vent looks easier.

Elbow below lavatory needs to be a long sweep. Toilet and standpipe vent bottoms should be combos (combines 45+wye).

Standpipe and its trap are 2 inch.
 

Scott Yackley

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Adjustments made. Agree, would be more challenging to tie the tub and shower into the toilet drain line. Thanks!
 

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DavidDeBord

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Per the 2018 IPC, an "Exception" is given:

Each fixture trap shall have a protecting vent located so that the slope and the developed length in the fixture drain from the trap weir to the vent fitting are within the requirements set forth in Table 909.1.

Exception: The developed length of the fixture drain from the trap weir to the vent fitting for self-siphoning fixtures, such as water closets, shall not be limited.

Is venting the toilet "run" required due to it's change of direction?
 

DavidDeBord

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Ok,... It's been ten days with no input,.... is there a source herein the group, with schematics?, notes?, Tips? related to this installation & my question?
 

Tuttles Revenge

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Ok,... It's been ten days with no input,.... is there a source herein the group, with schematics?, notes?, Tips? related to this installation & my question?

I think you aren't getting a response because you tacked on your question onto someone elses Thread. Post a new topic of your own and you will get a better response. as is, it just looks like you're adding to the above conversation. I'm not familiar enough with the IPC to give a qualified answer otherwise I would.
 

wwhitney

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The WC always needs a vent. Often you can wet vent it, so it doesn't have to be a dry vent. But in this case that won't work:

The details depend a little on plumbing code. The OP is in MI, which uses the UPC, which requires a vent within 6'. If the run to the stack is over 6', then the dry vent is required for that reason (the bend doesn't matter). Even if under 6', the UPC restricts vertical wet venting to stacks receiving the discharge of 1 and 2 DFU fixtures, but the washing machine standpipe is a 3 DFU fixture, so the dry vent is required. [The laundry standpipe dry vent could be eliminated, as the laundry sink is a 2 DFU fixture, so its vent can wet vent the laundry standpipe, since the stack is already upsized from the minimum laundry sink drain size.]

The IPC has no limit on the length of the WC fixture drain, but it limits vertical wet venting to bathroom group fixtures, so not for a laundry sink or laundry standpipe. It does allow vertical common venting of any two fixtures, but that doesn't apply to the WC, as it has two fixtures above it. [Although again, the laundry standpipe dry vent could be eliminated, so the standpipe is common vented with the laundry sink.]

Cheers, Wayne

Edit: oops, I mixed up my Midwest states, MI (Michigan) is IPC, MN (Minnesota) is UPC.
 
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Scott Yackley

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Finally about to start the DWV installation at our cabin. Here is the final layout. Any issues anyone can see?
 

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wwhitney

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- The vent takeoff on the laundry machine standpipe trap arm is not necessary, the stack can vent that trap. The stack has only one drain coming in higher, the laundry sink, and the IPC allows any two fixtures to be "common vented" on the same floor level.

- The only issues I see are on the loop that include the water softener standpipe trap, the utility sink, and the floor trap. The vent on that loop needs to be at least 6" above the shower and master WC flood rims before it connects to their vent. Also, if the water softener standpipe is on the floor above the utility sink, then the utility sink vent needs to be separated from the water softener standpipe drain; there's no vertical wet venting or common venting between floors.

Cheers, Wayne
 

Reach4

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The vent on that loop needs to be at least 6" above the shower and master WC flood rims before it connects to their vent.
I think that vent split also needs to be 6 inches higher than the top of the standpipe.
 

Scott Yackley

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Thanks for the feedback. Removed the vent takeoff for the laundry, and made the adjustment to vent the water softener, utility sink, and floor trap farther up above the flood rims. Water softener is on the same floor as the utility sink and drain in the basement, so should be ok there. See attached updated layout.
 

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wwhitney

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Nothing else jumps out at me. I'm not 100% clear on floor drain venting rules, but seems like it should work. Will you have a trap primer for it?

I'm also not familiar with water softeners, and I'm idly wondering if there's a reasonable configuration that causes the floor drain and the water softener to share the same trap (e.g. an indirect discharge from the water softener into the floor drain). That would keep the floor drain trap from drying out, in lieu of a trap primer.

Cheers, Wayne
 

Scott Yackley

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All of the plumbing at the basement floor level is already done (under concrete), and there is not a trap primer for the floor drain.
 

Reach4

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I'm also not familiar with water softeners, and I'm idly wondering if there's a reasonable configuration that causes the floor drain and the water softener to share the same trap (e.g. an indirect discharge from the water softener into the floor drain).
One way is to not have a standpipe, but to to have the softener discharge an inch above the floor drain grill.
Not very pretty looking.
 
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