# Code question for BC...



## iamzoner (Oct 29, 2009)

I was on a job site in British Columbia. It is a 4 story retirement home. The kitchens of all 4 floors are being drained into a 2" stack. So 4 times 1 and a half fixtures which to me equals 6 fixture units.

My code book states that a 2" stack can handle up to 24 fixture units vertical and 6 fixtures horizontal. It also states that a 2" line can wet vent up to 4 fixture units as long as it doesn't serve water closets.

My question is, if this 2" stack is serving as a wet vent for the entire kitchen line, it is actually serving a total of 4.5 fixture units as a wet vent, not 4. Is this just one of those things that an inspector will pass anyway?

Just trying to learn the codes on my own as I go here.


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## futz (Sep 17, 2009)

iamzoner said:


> My question is, if this 2" stack is serving as a wet vent for the entire kitchen line, it is actually serving a total of 4.5 fixture units as a wet vent, not 4. Is this just one of those things that an inspector will pass anyway?


Totally depends on your inspector. Where I work (Delta/Richmond/Surrey/etc.) they won't let us slide at all. If we're 1/2 a fixture unit over then that's it - upsize it or do it different. In Kamloops (and many other smaller towns) I bet you get a pass. They'd let it slide in Kelowna for sure (don't get me started about their inspectors ).

Will it work at 4.5 FU? Of course it will. It'll be fine. But any municipality that's been successfully sued lately will be gun-shy and will enforce very strictly. :laughing:


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## markb (Jun 11, 2009)

According to the Ontario Building code, which is very close to the NPC or BC plumbing code, states that wet-vents (Single or multi-story) must be sized according to your wet-vent charts. It may only serve one WC at first (bottom) connection (two WCs can be wet vented, but must use a double Y fitting). 

The 4 FU rule applies to the maximum FU allowed to be drained PER FLOOR. 

Less than 4 stories means that you can connect to the rest of the in-house venting system. 

More than 4 stories requires the vent to be taken through the roof (sized as a vent terminal, 3" min).

Hope that helps!


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## Pipe Rat (Apr 5, 2009)

Are you saying each floor just has a branch to the kitchens and they are not individually vented? Don't think that would fly in my neck of the woods.


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## Tommy plumber (Feb 19, 2010)

So there is one vertical line serving as both drain and vent for 4 floors? That won't pass here. Wet venting is permitted only for fixtures on same floor level.


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## iamzoner (Oct 29, 2009)

Yes. It is 1 2" stack which serves as both drain AND vent for all 4 floors. I spoke with someone locally here in my town and they said to check my code book for what a STACK can handle. Sure enough, a 2" stack can handle 24 fixture units vertical and 6 horizontal.

So I guess that even though this looks like a wet vent to me, I may simply have it confused as a stack that goes up all 4 floors. The only fixture that goes into this stack on each floor is the kitchen.

I may be confused by the definition of wet venting vs a stack. But if this stack is also its own vent, isn't that a wet vent? Isn't any stack that serves as its own vent a wet vent?


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## markb (Jun 11, 2009)

iamzoner said:


> Yes. It is 1 2" stack which serves as both drain AND vent for all 4 floors. I spoke with someone locally here in my town and they said to check my code book for what a STACK can handle. Sure enough, a 2" stack can handle 24 fixture units vertical and 6 horizontal.
> 
> So I guess that even though this looks like a wet vent to me, I may simply have it confused as a stack that goes up all 4 floors. The only fixture that goes into this stack on each floor is the kitchen.
> 
> I may be confused by the definition of wet venting vs a stack. But if this stack is also its own vent, isn't that a wet vent? Isn't any stack that serves as its own vent a wet vent?


It is sized as a wet vent, not as a stack. The definition part of your code book should explain the differences. 

Also, keep in mind the limited distances for offsets.

Your code book should have a few examples of this in the appendix. 

One thing to keep in mind as well is to use a TY or (better) a Y and FITTING (not regular) 45 at each branch connection; to stay withing the trap arm requirements.


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## Redwood (Sep 8, 2008)

Piperat said:


> Are you saying each floor just has a branch to the kitchens and they are not individually vented? Don't think that would fly in my neck of the woods.





Tommy plumber said:


> So there is one vertical line serving as both drain and vent for 4 floors? That won't pass here. Wet venting is permitted only for fixtures on same floor level.


Yep, there are a lot of things different in the codes north of the border. I do however pay attention to what they do because it is interesting to compare the differences...

Things like yellow ABS Cement, kitchen sink traps under the floor, venting between floors are just a few of the differences...


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## markb (Jun 11, 2009)

Redwood said:


> Yep, there are a lot of things different in the codes north of the border. I do however pay attention to what they do because it is interesting to compare the differences...
> 
> Things like yellow ABS Cement, kitchen sink traps under the floor, venting between floors are just a few of the differences...



Why wouldn't you be able to vent between floor joists? Or back vent kitchen sink traps?


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## Redwood (Sep 8, 2008)

We can't wet vent between floors and we also have a maximum fall on a drain before the trap.
And we have black ABS cement...


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## markb (Jun 11, 2009)

Redwood said:


> We can't wet vent between floors and we also have a maximum fall on a drain before the trap.
> And we have black ABS cement...



... weird....


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## Redwood (Sep 8, 2008)

markb said:


> ... weird....


Some of the guys were thinking the same thing about the way you guys do it up north...:laughing:

It's just the way it is...


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## Tommy plumber (Feb 19, 2010)

Theoretically if a single vertical drain line is oversized, say 4" or 6", then it in theory would be able to act as both a vent and drain for a multi-story application, let's say a kitchen stack. But code doesn't permit it here.


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## AKdaplumba (Jan 12, 2010)

a 4 storey with a kitchen stack is a wet vent. 6 FU is over so its upped to 3"


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## iamzoner (Oct 29, 2009)

*Thanks*

I agree, according to my code book, the stack could only legally do 4 extra units, not 4.5. So to me it should be a 3 inch stack. It is not though, it's a 2 inch stack serving 3 floors above the main floor. Somehow, I suppose they get away with it here.

Thanks for the help everyone.


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## futz (Sep 17, 2009)

Redwood said:


> And we have black ABS cement...





markb said:


> ... weird....


They sold black ABS glue for a few years here in B.C. (probably way before markb's time). I never liked it much. Too easy to miss a joint when things weren't well lit. With yellow you can tell at a glance whether you've glued every one. With black you have to take a good light and look really close - it's sometimes tough to see. Give me my lovely yellow Y2 and I'm a happy guy. :thumbup:

Another difference my dad told me about (he has done some work in the States for relatives) is that ABS is sold in 10' lengths down there. Only 12' lengths are available here (to my knowledge). Maybe that's only true for retail - I don't know - I don't go south at all even though the border is only 20 minutes from where I live.


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## futz (Sep 17, 2009)

Tommy plumber said:


> Theoretically if a single vertical drain line is oversized, say 4" or 6", then it in theory would be able to act as both a vent and drain for a multi-story application, let's say a kitchen stack. But code doesn't permit it here.


Isn't that strange! What do you do when you plumb apartments? Whenever possible they're all stacked and wet vented like that here. It's the only sensible way (I bet you have another sensible way ).


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## ILPlumber (Jun 17, 2008)

futz said:


> Isn't that strange! What do you do when you plumb apartments? Whenever possible they're all stacked and wet vented like that here. It's the only sensible way (I bet you have another sensible way ).


Some folks run a vent stack and a soil stack.


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## plumber666 (Sep 19, 2010)

Love multi-storey wet vents. Size the whole wet vent stack for 6FU, 3" and it's all good, but watch out if the stack is offset. You've got a Code Book, read up. If they got away with 2" in the past, so be it, but the reason these things are oversized is for trap siphonage and blow outs. A 2"er is trouble.


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## bigdawginc (Sep 6, 2010)

*Phila. Plg code*



redwood said:


> we can't wet vent between floors and we also have a maximum fall on a drain before the trap.
> And we have black abs cement...


 yo what up in the city of phila. We can run 12ft for a small fixture waste, 8 ft. For a water closet! Go to phila. Gov & check it out! Anyway most a the time i prefer ibc ove phila. Because one full size vent ,& the size on all the others! In phila. All soilstacks must remain full size! Hope this helps matt b. Aka bigdawg


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## Tommy plumber (Feb 19, 2010)

quote=futz;139244]Isn't that strange! What do you do when you plumb apartments? Whenever possible they're all stacked and wet vented like that here. It's the only sensible way (I bet you have another sensible way ).[/quote]


In a multi-story application, there has to be (1) stack which receives the waste (like solids), and another separate line (vent) which cannot receive any waste, it only acts as a vent. I tried to post an iso but forum limit is 200K and my iso is like 400K, so I can't upload.


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## futz (Sep 17, 2009)

Tommy plumber said:


> In a multi-story application, there has to be (1) stack which receives the waste (like solids), and another separate line (vent) which cannot receive any waste, it only acts as a vent.


Ya, we can do it that way as well, but the added abiity to do a wet vent for less heavily loaded stacks gives us more flexibility.


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## iamzoner (Oct 29, 2009)

*Stacks and vents*

I have seen the drainage stack + vent stack combination as well though it is usually for the bathroom lav system. **** stacks take the drainage and usually get wet vented out the same lavs tied to the vent stack.

When it comes to laundries and kitchens though, these are usually run up with larger wet vented stacks rather than separate vent stacks. Above the last floor, all the venting is tied together and run through the roof anyway.

My original question was based on the fact that I was always used to seeing a 3" stack for wet venting the kitchens. This was the first time I have seen only a 2" stack. Normally I would see a 3" stack catching all the kitchens and a 3 inch stack catching all the laundries except for the main floor laundry which is usually drained in a separate 2 inch line and tied to the main floor stack vent for the lav system.


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