# loop vent



## plumber75 (Aug 31, 2013)

Hi guys I'm in north California I have just done the piping for a sink on a peninsula where I had to flat vent in a pony wall about 6' with 1/4" grade back to the drain. The inspector had come by when I was not there and told the framer that I needed to install a loop vent. From my understanding that is only aloud on island sinks is this guy stupid or is that a normal practice.?


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## Redwood (Sep 8, 2008)

I'll assume 1 1/2 pipe was used...
In which case he's probably 100% correct...

Larger dia pipe will get you a longer distance...


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## plumber75 (Aug 31, 2013)

The drain is 2" and the vent is 1.5" can you tell me where in the code I can find that? 
Thanks


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## plumber75 (Aug 31, 2013)

This is the closest thing I found but I'm within those limitations


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## Redwood (Sep 8, 2008)

Ok I had assumed you went over the max developed length...


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## GAN (Jul 10, 2012)

Section 913 covers "Island Venting"

Problem with the IPC, is under definitions "Island Vent" does not exist. Section 905.4 would get you on the vertical rise. So he may require an Island Vent.

You may also want to look up maximum developed length and the 20% rule, for horizontal venting.

Here in Illinois, Island Venting is only allowed on an Island not a peninsula.


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## justme (Jul 4, 2012)

I don't plumb in NC but here if you can get the vent 6" above flood rim level (typically 42") of the fixture you're feeding then there's no reason you can't turn horizontal and run the vent back to a full wall to run out the roof. Is your vent 6" above the flood rim level BEFORE you turn horizontal?


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## BumbleBee (Jan 24, 2015)

plumber75 said:


> Hi guys I'm in north California I have just done the piping for a sink on a peninsula where I had to flat vent in a pony wall about 6' with 1/4" grade back to the drain. The inspector had come by when I was not there and told the framer that I needed to install a loop vent. From my understanding that is only aloud on island sinks is this guy stupid or is that a normal practice.?


I maybe missing something, but why wouldn't you just install a AAV? We pretty much use AAVs on all our kitchen sinks, then through the roof with everything else. The IPC only requires you to have one VTR on any house.


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## jmc12185 (Aug 27, 2013)

BumbleBee said:


> I maybe missing something, but why wouldn't you just install a AAV? We pretty much use AAVs on all our kitchen sinks, then through the roof with everything else. The IPC only requires you to have one VTR on any house.


 Having anything mechanical on DWV is not really a good idea. It's bound to fail at some point.


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## Flyout95 (Apr 13, 2012)

BumbleBee said:


> I maybe missing something, but why wouldn't you just install a AAV? We pretty much use AAVs on all our kitchen sinks, then through the roof with everything else. The IPC only requires you to have one VTR on any house.


AAVs aren't code everywhere. In IL we can't use them.


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## Redwood (Sep 8, 2008)

Flyout95 said:


> AAVs aren't code everywhere. In IL we can't use them.


Who would want to... They are hacktastic.....


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## plumber75 (Aug 31, 2013)

justme said:


> I don't plumb in NC but here if you can get the vent 6" above flood rim level (typically 42") of the fixture you're feeding then there's no reason you can't turn horizontal and run the vent back to a full wall to run out the roof. Is your vent 6" above the flood rim level BEFORE you turn horizontal?


No but it is limited structurally which follows 905.3


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## plumber75 (Aug 31, 2013)

They don't even allow aav out side for a bbq sink in California.


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## GAN (Jul 10, 2012)

Not limited structurally. Just bad planning on the Architect or General. The short wall behind the sink should have been high enough to allow for your vertical vent 6" ACL.


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## BumbleBee (Jan 24, 2015)

We rarely use them, but for situations like this we will. We are under the IPC here though.


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## Plumbus (Aug 4, 2008)

If you look at the bottom of the second column of Table 7-5 in your 2014 California Code Book, for 1-1/2" pipe it allows a maximum of 60' for combined horizontal and vertical vent piping.


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## sparky (Jan 8, 2014)

Flyout95 said:


> AAVs aren't code everywhere. In IL we can't use them.


Not allowed in ky either,except on mobile homes,but mobile homes are not under ky state plbing code rules and regulations


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## Plumbergeek (Aug 16, 2010)

AAV & Sharkbites are all the rage with "Plumbers" here in Georgia.


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## HonestPlumb (Jan 25, 2015)

Flyout95- I agree. We can use them here in NJ, but only on an island vent or an exception that the inspector would approve. jmc12185, I also am not a fan of mechanical vents. Even in island sinks where we are allowed to use them and it is a heck of a lot easier than a loop vent. Depending on the inspector,for an island they will approve a 2" with a developed length no longer than 8' from trap to where it ties into a vented drain. To each his own. I still refuse to use Pex for water and flexible gas lines except an underground line.


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## plumber75 (Aug 31, 2013)

So here is what I originally installed









And this is what the idiot inspector made me install, why? I have no idea.


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## HonestPlumb (Jan 25, 2015)

Appears the inspector did not have a good night previous to your inspection. In NJ your original shot would have been fine. It is tough because they have the authority to enterpit the code as thy see fit. If you were there when he came to inspect, where I am some times that makes the difference in him saying " next time...." and passing it this time.


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## GAN (Jul 10, 2012)

WTF, am I missing something........ All you did is install copper instead of ABS???


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## plumbdrum (Nov 30, 2013)

plumber75 said:


> So here is what I originally installed
> 
> View attachment 44065
> 
> ...



The idiot is you and not the inspector, you "corrected" the "violation" by changing out your ABS to copper? This is another plumbing 101 situation. Go back in your notes from apprentice school and think about this one.


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## plumbdrum (Nov 30, 2013)

I guess maybe the easiest question is what is the height of your wall?


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## Bayside500 (May 16, 2009)

why not just put the stack in side wall and run a 2" waste arm ?


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## Tommy plumber (Feb 19, 2010)

GAN said:


> WTF, am I missing something........ All you did is install copper instead of ABS???












My guess would be a combustibility factor in a non-sprinkled building. But the studs are wood? 

To original poster: go ask why the inspector made you do that. Then you'll know in the future.


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## plumbdrum (Nov 30, 2013)

I think it's obvios


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## justme (Jul 4, 2012)

plumbdrum said:


> I think it's obvios


I don't think it is obvious , for one it's a wing wall and the actual plumbing wasn't changed just the type of material . Where the copper vent ties into is still ABS you can see that from the picture. So if you know why spit it out.


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## justme (Jul 4, 2012)

The only other change I see after looking again is that there weren't any nail plates in the ABS pics on anything but I don't see being failed for no nail plates and then being made to put in copper dwv .


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## plumbdrum (Nov 30, 2013)

justme said:


> I don't think it is obvious , for one it's a wing wall and the actual plumbing wasn't changed just the type of material . Where the copper vent ties into is still ABS you can see that from the picture. So if you know why spit it out.



Ok, so again I ask the height of the wall? so by changing the material the code violation went away? Is the vent 6" above the flood lever rim ? Could the drain been changed out to a larger diameter for his branch arm off his vent? The inspector may have been on the money with the loop vent.it looks like a 3' high wall, so do the math


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## plumbdrum (Nov 30, 2013)

Again plumbing 101


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## HonestPlumb (Jan 25, 2015)

Sometimes we tend to over think, there by looking past the obvious ! Correct plumbdrum ?


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## Leach713 (Nov 1, 2013)

plumbdrum said:


> I guess maybe the easiest question is what is the height of your wall?



... All I could think off is the vent not being at 42" for the revent and the nail plates


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## plumbdrum (Nov 30, 2013)

Leach713 said:


> ... All I could think off is the vent not being at 42" for the revent and the nail plates



Bingo


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## chonkie (Jul 31, 2014)

I've run into this before but the inspector made them raise the height of the wall so I could have my vent above the flood rim. I don't see how changing the abs to copper will make a difference if the sewer does indeed back up that much. I think a lot of people here are thinking the same thing.


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## Ghostmaker (Jan 12, 2013)

Was your vent in that wall 6 inches above the flood level rim of the sink?

As for the copper passing over ABS I have no idea and know no code requirement.


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## Mykeeb33 (Mar 6, 2015)

I would pass that. It looks great. Inspectors should use common sense. That installation will never have a venting problem.


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## plumbdrum (Nov 30, 2013)

Na, never.?????


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## jeffreyplumber (Dec 7, 2009)

Dont see a problem with your vent. And whether it is 42 inches high or as our code wants 6 inches above flood level dosent matter. Code only allow an island vent when structural condition prohibit a normal vent. Also code states that if a vent cannot rise verticaly it can break horizontaly and be run with grade at the highest possible height allowed by the structure. Also island venting isnt an option its only to be used when structural conditions force it. So If I were to see you put an island vent where it wasent needed and I was an inspector We would be having a conversation


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## HonestPlumb (Jan 25, 2015)

*Island Vent*



jeffreyplumber said:


> Dont see a problem with your vent. And whether it is 42 inches high or as our code wants 6 inches above flood level dosent matter. Code only allow an island vent when structural condition prohibit a normal vent. Also code states that if a vent cannot rise verticaly it can break horizontaly and be run with grade at the highest possible height allowed by the structure. Also island venting isnt an option its only to be used when structural conditions force it. So If I were to see you put an island vent where it wasent needed and I was an inspector We would be having a conversation


Jeff- I think yours is the most logical and code adhering explanation of them all.


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## plumbdrum (Nov 30, 2013)

So, the wall be 36" height say would not be a structural issue, it's ok to have a clear code violation. I'd make a killing with re inspection fees with you guys. Come on over to Ma, I'll lay out the red carpet. The plumber should have planned out his drain better. He should have ran his branch arm at 15" and installed a 2" pipe ,it would have made more sense, I would even except it if he stretched by 6", but that's a no no what he has there.


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## plumbdrum (Nov 30, 2013)

Mykeeb33 said:


> I would pass that. It looks great. Inspectors should use common sense. That installation will never have a venting problem.



The person who should have had common sense is the installer.the inspector was doing his job. Don't understand why or even if he told him to change the vent to copper.


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## plumbdrum (Nov 30, 2013)

And I've asked several times, what Is the height of the wall?????


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## jeffreyplumber (Dec 7, 2009)

height of the wall wouldnot be an issue. UPC code allows vents to be run bellow flood level if no other way can be done. so long as use fittings of drainage and not vent 90s etc and give it 1/4 per foot grade. however code says you must run the vent as high as possible if less than 6 inch above flood level. Well mayby plumbing 101 Ive done a vent like he did and the inspector said why didnt i bring my waste up the side wall and run a trap arm across the outside of the wall i guess cus hindsights 20 20 and you cant allways tell if its gona be too long or not. Ive also roughed in an island vent and been made to rip it outbecause it could be vented otherwise. Its pretty easy to walk through a job and pick it apart, best we can do is learn all we can to avoid it.


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## jeffreyplumber (Dec 7, 2009)

Sorry Guys, guess I missed some posts and the detail in the picture. I hate to do it this way but a 2 inch dirty arm and trap coming from the side wall is probebly the best way because running the vent low is only legal when other ways arent possible. of course a dishwasher or trash compactor on the left side may make it difficult.


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## HonestPlumb (Jan 25, 2015)

There are several ways to do island vents and when you have a window right above the kitchen sink. That you cant get your 6" above rim. What I will do is prior to doing it I will call the local inspector and ask which he prefers given the situation. I have done them all of the ways previously mentioned. The best way to do it is the way that you will pass inspection from that particular inspector! Simple.


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## plumbdrum (Nov 30, 2013)

jeffreyplumber said:


> height of the wall wouldnot be an issue. UPC code allows vents to be run bellow flood level if no other way can be done. so long as use fittings of drainage and not vent 90s etc and give it 1/4 per foot grade. however code says you must run the vent as high as possible if less than 6 inch above flood level. Well mayby plumbing 101 Ive done a vent like he did and the inspector said why didnt i bring my waste up the side wall and run a trap arm across the outside of the wall i guess cus hindsights 20 20 and you cant allways tell if its gona be too long or not. Ive also roughed in an island vent and been made to rip it outbecause it could be vented otherwise. Its pretty easy to walk through a job and pick it apart, best we can do is learn all we can to avoid it.



Under Ma code , you can use a flat vent only for a floor drain/flat bottom fixture , vent needs to be rolled above center line and run to nearest wall, ONLY if it is not possible or practical. That job was totally possible to do correct. Also in Ma Bow/Loop vents are allowed on peninsula and island that cannot be vented traditionally.


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## wyrickmech (Mar 16, 2013)

He should have just brought the drain up in the solid wall and armed over with 2 in. That would allow him 6 feet problem solved. Here we do not allow any horizontal venting at that elevation.


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## plumbdrum (Nov 30, 2013)

wyrickmech said:


> He should have just brought the drain up in the solid wall and armed over with 2 in. That would allow him 6 feet problem solved. Here we do not allow any horizontal venting at that elevation.



Exactly


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## Mykeeb33 (Mar 6, 2015)

If you went with a 2" dirty arm, looks like it would be too long.


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## plumbdrum (Nov 30, 2013)

That's definitely within 6'


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## HonestPlumb (Jan 25, 2015)

Mykeeb- I think what you refer to as a dirty arm I call a waste arm. I believe with 2" you can travel 8' from trap weir to vent TY..I could be wrong. I think that would be acceptable where I am.


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## jeffreyplumber (Dec 7, 2009)

Some good points and acoording to upc code which is ca. the only legal way would be to come up in that side wall. However it is often allowed and practiced to offset low with grade but it can bite you . We have an awful lot of homes here with slab on grade construction and if you come up in the wrong spot could cause jack hammering if not caught on the ground work. also contactind an inspector is a good idea but when we often work in many differant citys and dont know the inspector just talking to one can be quite a chore as office hours and acess to a real live talking inspector (hopefully the one that comes to your job)


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## Mykeeb33 (Mar 6, 2015)

UPC chapter 10: TRAPS & INTERCEPTORS. Table 10-1 horizontal distance to trap weir from vent says 5'-0" for 2"........ For 1-1/2" it's 3'-6". That's in my 2003 UPC edition so maybe it's changed since then. I'm retired so I'm not buying a new one!


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