Running vent across basement ceiling

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Chris Curtin

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Hi,
I'm designing the basement finishing and have an interesting problem. The builder put in an ejector pit, stubbed bathroom, drain extension, vent extension, capped water lines etc. on the upper left side of the basement. My wife wants a full kitchen on the right side.

Using a pump to push the sink & dishwater wastes is actually easy since the existing kitchen is right above it and the drain is easily accessible in the basement ceiling for a pump to push it up.

The problem is the vent for the pump in the kitchen. Since the kitchen above only has a sink and dishwasher, the builder put an AAV (to code) in the drain. So no vent to tap into. I know I can't use an AAV here since the pump needs to pull/push air.

How can I run a vent line 50+ feet to the vent at the ejector pit?

The joists run north/south (assuming the top of the picture is north). They are 12" high I beams, so getting a pitch that long would be hard/impossible. All the plumbing runs from the lower right, across the wall then under the stairs to the sewer in the upper right, so the rest of space on the bottom is pretty open.

Thanks
Chris

basement-12-16.jpg
 

Tuttles Revenge

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Vents don't need to be graded. They can be installed flat level. Is there a closet upstairs that the wall could be opened up to access the attic space to run the vent through the roof? Sump vents really want to be run individually through the roof per UPC rules. But can be combined if necessary.
 

wwhitney

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The code language on that varies a bit between the IPC and the UPC. UPC 905.1 says "Vent and branch vent pipes shall be free from drops or sags, and each such vent shall be level or shall be so graded and connected as to drip back by gravity to the drainage pipe it serves." That clearly allows level.

https://up.codes/viewer/california/ca-plumbing-code-2019/chapter/9/vents#905.1

While IPC 905.2 says "Vent and branch vent pipes shall be so graded and connected as to drain back to the drainage pipe by gravity." But I don't think the IPC specifies a minimum slope for that, however. So while you can't go level, you could go below 2%. And where to draw the line is unclear, is 1/2% OK?

https://up.codes/viewer/colorado/ipc-2018/chapter/9/vents#905.2

Cheers, Wayne
 

Jeff H Young

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1/2 % is fine. lets say I'm laying the pipe on top of some ceiling joists why not just secure pipe flat ? Otherwise you need to shim the pipe to allow slope why bother? If your drilling out floor joists it's just as easy to give a little grade on it .
If it's easy enough might as well give a little grade on it, if the pipe is nice straight cast iron barely any fall. but if its ABS and bowed heavily and a short run I might give a 1/4 " 2 % just so no one sees a spot that's back grading can't have that
 

Chris Curtin

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Thanks. An interesting idea from a neighbor: split the pitch difference. So angle up (away) from the kitchen pump, angle down (towards) the sewer ejector vent. Somewhere mid room pull the PVC closer to the inside of the joist making a slight hill. Now any water in the vent will flow towards one of the two drains. Thoughts? Overkill?
 

Reach4

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Thanks. An interesting idea from a neighbor: split the pitch difference. So angle up (away) from the kitchen pump, angle down (towards) the sewer ejector vent. Somewhere mid room pull the PVC closer to the inside of the joist making a slight hill. Now any water in the vent will flow towards one of the two drains. Thoughts? Overkill?
IPC is fine with that. Not overkill IMO.

Two 22.5s in series at the apex can give any angle between zero and 45 degrees.
 

Tuttles Revenge

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Theres enough flexibility in plastic pipe to create a slight offset without fittings. Vent slope is in practical issues a Non Issue above the flood level of the fixture. Air will flow as intended as long as the vent pipe is not blocked.
 

Jeff H Young

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Yep not an issue at all but general workmanship says don't have low spots in it even 2 inches in 50 ft is good. if somehow a 1/8inch of water or condensation build up would never hurt a thing. Pretty much non issue give it a little fall anything is good would be my advice
 
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