Basement Bathroom Plans (Revised)

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RifRaf

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Hello everyone! My name is Mike and I'm a new member to this forum. Over the years I have done many DIY home plumbing repairs and while doing my research, this site always provided me with excellent information to complete my tasks.

I am in the very early stages of planing a new basement bathroom consisting of a water closet, LAV, and shower. I will also be installing a new sewage ejector basin and pump under the concrete slab. I live in Baltimore, Maryland and believe we use the IPC.

I have been researching this project for several months to educate myself about the proper use of Drain-Waist-Vent (DWV) pipes and fittings, and this forum has been a very valuable resource... so I thought it was due time to join!

Attached below are some preliminary bathroom plans. I did a couple different views to help with the interpretation of the plans.
Any suggestions... or "mistake call outs" would be greatly appreciated! Thanks in advance!
NOTE: I also included a page I used for planning my sewage ejector pump plumbing and venting.
 

Attachments

  • 1 NEW Plumbing DWV Diagram (Floor Drain Z+Lav +Laundry Tub Vent+Separate Basin Vent).jpg
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  • 2 NEW Top View Basement Bathroom DWV Plan+Type.jpg
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  • 3 New Bathroom DWV Line Plan+Type.jpg
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  • 4 Sewage Ejector Pump Code Requirements.JPG
    4 Sewage Ejector Pump Code Requirements.JPG
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James Henry

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Floor drains don't require an individual vent. DON'T EVER! flush wipes or feminine products down a toilet that has a sewage ejector. Provide a floor plan and you will get some replies.
 

wwhitney

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Some comments:

- The note on the last image about the sewage ejector vent not combining with the house venting system is not a requirement of IPC to my knowledge.

- A dry vented floor drain may not wet vent another bathroom fixture (shower in the diagram).


- Showing horizontal vent piping and horizontal drain piping on the same floor plan is confusing. I'd suggest omitting the horizontal vent piping, and just showing the vertical vent takeoffs with labeled circles.

Cheers, Wayne
 

RifRaf

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Provide a floor plan and you will get some replies.
James, Thank you for the comments!
I have added a floor plan to the revised drawings below.
- A dry vented floor drain may not wet vent another bathroom fixture (shower in the diagram).
wwhitney, Thank you for the comments!
I revised the plans and added a dry vent to the shower.

I did a little more reading on the forum and noticed that connecting a laundry sink drain into a wet vented bathroom (WC) pipe may not pass code in some locations (UPC vs IPC?). On my revised plans, I separated the laundry sink drain (and the LAV drain) from the WC vent pipe, so now all of the drains are dry vented. I have a feeling that I am over vented... but I am okay with that.

If you feel that it is not necessary to separate the laundry sink from the bathroom group. I can go back to combining the laundry sink + LAV drains with the WC vent as previously shown in post #1.
- The note on the last image about the sewage ejector vent not combining with the house venting system is not a requirement of IPC to my knowledge.
That is good to know! This way I can combine the sewage ejector vent with the existing house venting in the attic and not have to install an additional roof top vent. I live in a ranch type home, so getting a vent from the basement to the attic should not be too much trouble. I currently have an existing 2" and a 3" roof top vent.
- Showing horizontal vent piping and horizontal drain piping on the same floor plan is confusing. I'd suggest omitting the horizontal vent piping, and just showing the vertical vent takeoffs with labeled circles.
Attached below are the Revised Basement Bathroom Plans and Floor Plan. I tried to simplify them per your suggestion.
Thanks again for the comments! Please let me know if there is anything else that needs to be addressed.
 

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  • Basement Bathroom Floor Plan Alter #1 Revised.JPG
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  • Bathroom DWV Line Plan Alter #1 Revised.jpg
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  • Plumbing DWV Diagram Alter #1 Revised.jpg
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wwhitney

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To dry vent a fixture, the dry vent must generally come off the fixture drain before it combines with another drain. However, the IPC does allow two fixture drains to combine and they receive a common dry vent, as long as the trap to vent requirements are satisfied for each fixture individually.

So the upshot is that if the floor drain trap to shower vent distance/drop is within the trap arm limitations (maximum one pipe diameter drop, minimum 1/4" per foot fall), you can delete the dry vent on the floor drain. If you don't, you still need the shower vent, as the floor drain is not allowed to wet vent the shower. And in that case it would be more typical to join the shower and the floor drain downstream of the shower vent, although I don't think there's anything wrong with the order you have.

Likewise, the WC dry vent is superfluous. Since you are bringing the dry vented shower drain in to join the WC fixture drain upstream of the vent, the shower drain is wet venting the WC, and you just have a downstream bonus vent. If you want to dry vent the WC, then the shower drain should just the WC drain downstream of the WC vent.

As for the laundry sink's effect on wet venting, a drain that is carrying the laundry sink's discharge can't be a wet vent. So if the first thing that the WC joined was the laundry sink, say, then that would be a problem--it can't wet vent the WC, and the WC hasn't been vented yet. But bringing the laundry sink in downstream of any wet vents, as your plans does, is fine; it has no effect on upstream fixtures.

Since you've now omitted the horizontal vent pipes for clarity, to double check, the rule on those it that they (and any junctions between fixture vents) must be 6" above the flood rim level of any fixtures served. On the sump vent, it's not 100% clear to me what you should consider its flood rim, but it's certainly no higher than the high point of the discharge line, just above the 4" main.

Cheers, Wayne
 

RifRaf

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Wayne, Thank you for the additional input and suggestions!
I now understand the difference between dry venting vs wet venting a drainage pipe... thanks for clearing that up.
the WC dry vent is superfluous. Since you are bringing the dry vented shower drain in to join the WC fixture drain upstream of the vent, the shower drain is wet venting the WC
I removed the extra WC vent per your suggestion (pointing out that the WC will now be wet venting thru the Shower vent).
The WC trap is only 4 feet from the Shower Vent (and I am using 3" drainage pipe for the shower) so I am well within spec to vent the WC as you suggested (both UPC and IPC). Even though IPC does not require it, I did increase the vent size of the shower vent to 2" (since it will also be venting the WC). I agree that the extra WC vent located on the WC drain pipe was excessive... and by removing it (and the associated fitting), it will make installing the plumbing between the WC and the Septic Pump Basin much easier.
... it would be more typical to join the shower and the floor drain downstream of the shower vent, although I don't think there's anything wrong with the order you have.
The reason I decided to join the floor and shower drain upstream of the shower vent was for clean-out access. With the current configuration, I can run a snake thru a clean-out port on the floor drain vent and work the snake thru nearly the entire run of buried drainage pipe. If I connected the floor and shower drain downstream of the shower vent, there could be a section of buried drainage pipe between the shower trap and the floor drain connection that might be difficult to snake.
But thanks for pointing out that the current configuration is acceptable!

As for venting, all horizontal runs of the vent pipes will be well above the flood rim level for the fixtures served.... and the connection to existing vent will happen in the attic. I have attached a simple version of a vent plan to help demonstrate the planned configuration. I have also attached some updated plumbing plans based on the changes discussed above.

Note: I understand that the floor drain vent is not really needed, but it gives me an good area to install a clean-out port... and adding a little more vent piping between the clean-out port and the shower vent will be very easy to do.

Once again, thank you for all of your help and suggestions!... and please feel free to call out anything I may have missed.
 

Attachments

  • Drain+Vent Side View Plan Alter #2.jpg
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  • Plumbing DWV Diagram Alter #2 Revised.jpg
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  • Bathroom DWV Line Plan Alter #2 Revised.jpg
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  • Basement Bathroom Floor Plan Alter #2 Revised.jpg
    Basement Bathroom Floor Plan Alter #2 Revised.jpg
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James Henry

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So the upshot is that if the floor drain trap to shower vent distance/drop is within the trap arm limitations (maximum one pipe diameter drop, minimum 1/4" per foot fall), you can delete the dry vent on the floor drain.
I've seen you suggest that more than once, that is not true. A floor drain is designated a "Combination waste and vent". there is no limit on trap to vent distance, just that there must be a vent somewhere in the drainage system and be on the same floor.
The reason I decided to join the floor and shower drain upstream of the shower vent was for clean-out access. With the current configuration, I can run a snake thru a clean-out port on the floor drain vent and work the snake thru nearly the entire run
You can put a cleanout in if you want but It is common to run a snake through the floor drain trap.
 

RifRaf

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You can put a cleanout in if you want but It is common to run a snake through the floor drain trap.
James Henry, Thank you for the feedback!

Speaking of floor drains... I was wondering if there is any preference to what type of floor drain to use that would prevent back-flow.
I have seen the 2" floor drain that incorporate a clean-out port molded into the drain/trap (see below)
1647629191571.png

... and have seen ball valves that are installed in these drains to prevent back-flow.
1647629630005.png

Or, would I be better off with a 3" floor drain with some type of diverter valve to prevent back-flow issues?
1647629902533.png

If there are any other suggestions on the best way to achieve this type of installation, I would welcome your recommendations.
Thanks!
 

wwhitney

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I've seen you suggest that more than once, that is not true.
I made the comment that a floor drain in a bathroom can be wet vented by one of the other fixtures if the resulting trap arm is within the length and fall limits, and that's certainly a true statement.

But I think your point is that floor drains are commonly vented via a Combination Waste and Vent, which is more flexible than Wet Venting. It's true that I had not read up on those, so I haven't been suggesting that design option.

For the UPC, 910.2 requires AHJ approval in each case; but I gather from your comments that in your area it's commonly granted for a floor drain, even one that could be vented otherwise?

The IPC allows CWV for floor drains, sinks and lavatories, no special approval required. So that's a good option I'll try to keep in mind.

Cheers, Wayne
 
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