Basement Plumbing Venting.

[MAYOR]

Hello,
Basement bathroom setup under concrete.
Please see sketch.
Will the 2" vanity sink wet vent be ok to vent toilet and shower as shown.
Thank you
Mayor

Please see sketch.

 

[Terry]

With current codes, yes.
The fitting off the main to the shower and the lav should by wye or combo fittings. No santees.

 

[Sponsor]

 

[MAYOR]

With current codes, yes.
The fitting off the main to the shower and the lav should by wye or combo fittings. No santees.

Yes wye fittings for sure. I'll leave the san tees for the vent connection.
Thank you

 

[wwhitney]

But the fixture connection order needs to be changed. The lav right now is the downstream most fixture, it needs to be one of the two upstream most. One of the US codes requires the WC to be last, and one of them doesn't, so check your Toronto plumbing code on that.

Cheers, Wayne

 

[MAYOR]

But the fixture connection order needs to be changed. The lav right now is the downstream most fixture, it needs to be one of the two upstream most. One of the US codes requires the WC to be last, and one of them doesn't, so check your Toronto plumbing code on that.

Cheers, Wayne

Interesting. OK I will check.
Thank you.

 

[MAYOR]

Verified. Layout is OK.

 

[wwhitney]

Verified. Layout is OK.

If you're referring to the layout in the OP, I'd be very interested to see the reference to the Toronto Plumbing Code that says that two unvented fixture drains can combine before then joining a third dry-vented drain to be wet vented by it. All the codes I'm familiar with would require, at a minimum, that the shower join the 4" line downstream of where the lav joins the 4" line.

Cheers, Wayne

 

[MAYOR]

If you're referring to the layout in the OP, I'd be very interested to see the reference to the Toronto Plumbing Code that says that two unvented fixture drains can combine before then joining a third dry-vented drain to be wet vented by it. All the codes I'm familiar with would require, at a minimum, that the shower join the 4" line downstream of where the lav joins the 4" line.

Cheers, Wayne

Best I can find.

 

[wwhitney]

None of the examples in that video have the wet venting fixture (the lav) as the 3rd on the line. You need to have the lav as one of the two upstream most fixtures.

Cheers, Wayne

 

[Tuttles Revenge]

Canadian National Plumbing Code 2015

Wet Venting (See Note A-2.5.2.1.) 1) A soil-or-waste pipe is permitted to serve as a wet vent, provided

a) the hydraulic load is in accordance with Table 2.5.8.1.,

b) the number of wet-vented water closets does not exceed 2,

c) where 2 water closets are installed, they are connected at the same level by means of a double sanitary T fitting if the vent pipe is vertical and by means of a double Y fitting if the vent pipe is horizontal,

d) the water closets are installed downstream of all other fixtures,

e) trap arms and fixture drains connected to the wet vent do not exceed 2 inches in size, except for connections from emergency floor drains in accordance with Sentence 2.5.1.1.(3),

f) the total hydraulic load on the wet vent does not exceed the limits stated in Table 2.5.8.1. when separately vented branches or fixture drains in the same storey, having a total hydraulic load not greater than 2 fixture units, are connected to the wet vent or a wet-vented water closet trap arm,

g) the hydraulic load of separately vented fixtures that drain into the wet vent are not included when sizing the continuous vent that serves the wet vent,

h) where a wet vent extends through more than one storey, the total discharge from any one storey above the first storey does not exceed 4 fixture units,

i) there is not more than one nominally horizontal offset in the wet vent, and i) the offset does not exceed 1.2 m for pipes 2 inches or less in size, or ii) the offset does not exceed 2.5 m for pipes larger than 2 inches in size,

j) the wet-vented portion is not reduced in size except for the portion that is upstream of emergency floor drains in accordance with Sentence 2.5.1.1.(3), and

k) the length of the wet vent is not limited.

 

[MAYOR]

From a Canadian plumbers forum.
Question: "I am a little confused by the statement “Toilets must be installed downstream of all other fixtures” In the example 1, it sure looks like the toilet is upstream of the sink."

Answer: "Try to imagine the toilet drains above the ty on the sink drain in figure 1. That would be upstream."

Answer is from a plumber who has been in business for a long long time.

 

[Reach4]

In “Toilets must be installed downstream of all other fixtures”, I would think they are saying that the toilet must not have a wet-vented shower or tub upstream of it. They are not including the lavatory, which is providing the wet venting, in that reference to fixtures. I think they could have worded that a lot better.

 

[wwhitney]

Just looking at the order in which fixtures join each other, i.e. ignoring pipe sizes and lengths, there is no upstream-most fixture. There is just an upstream-most junction, which lets you say what the two upstream most fixtures are. Downstream of that point, if the fixtures join one at a time, there is a well-defined order.

Cheers, Wayne

 

[MAYOR]

But the fixture connection order needs to be changed. The lav right now is the downstream most fixture, it needs to be one of the two upstream most. One of the US codes requires the WC to be last, and one of them doesn't, so check your Toronto plumbing code on that.

Cheers, Wayne

Wayne after staring at my sketch and trying to figure things out I'm slowly starting to understand what you are saying. So this leaves me in a predicament. How do I vent the shower?

 

[MAYOR]

In “Toilets must be installed downstream of all other fixtures”, I would think they are saying that the toilet must not have a wet-vented shower or tub upstream of it. They are not including the lavatory, which is providing the wet venting, in that reference to fixtures. I think they could have worded that a lot better.

Certainly messes me up.

 

[wwhitney]

So this leaves me in a predicament. How do I vent the shower?

If you want to wet vent the shower, you have to combine the lav and the shower first, then they both join the WC. How deep the is the 4" line? If you have sufficient available depth, the lav/shower can be higher or lower than the WC.

Cheers, Wayne

 

[MAYOR]

Just looking at the order in which fixtures join each other, i.e. ignoring pipe sizes and lengths, there is no upstream-most fixture. There is just an upstream-most junction, which lets you say what the two upstream most fixtures are. Downstream of that point, if the fixtures join one at a time, there is a well-defined order.

Cheers, Wayne

If you want to wet vent the shower, you have to combine the lav and the shower first, then they both join the WC. How deep the is the 4" line? If you have sufficient available depth, the lav/shower can be higher or lower than the WC.

Cheers, Wayne

Looks like I'm euchred. I would need to drill through the 4" to combine them.

Is it possible for me to do something like this?
Trap arm would be much longer and I could connect into a (dry) vent.

If you want to wet vent the shower, you have to combine the lav and the shower first, then they both join the WC. How deep the is the 4" line? If you have sufficient available depth, the lav/shower can be higher or lower than the WC.

Cheers, Wayne

 

[wwhitney]

So this is a basement, with a concrete slab, but the 4" branch is just below the slab, not, say, 6" clear below the slab?

Then you either route the lav drain behind the WC to come hit the shower drain first (the length of the lav drain/wet vent is not limited, while the shower trap arm is limited). Or you dry vent the shower.

To dry vent the shower you need to route the shower drain under or next to a wall in which you can pull off the dry vent vertically and stay vertical. The diagram you posted is no longer allowed as the dry vent can't go horizontal until 6" above the fixture flood rim.

Cheers, Wayne

 

[MAYOR]

So this is a basement, with a concrete slab, but the 4" branch is just below the slab, not, say, 6" clear below the slab?

Then you either route the lav drain behind the WC to come hit the shower drain first (the length of the lav drain/wet vent is not limited, while the shower trap arm is limited). Or you dry vent the shower.

To dry vent the shower you need to route the shower drain under or next to a wall in which you can pull off the dry vent vertically and stay vertical. The diagram you posted is no longer allowed as the dry vent can't go horizontal until 6" above the fixture flood rim.

Cheers, Wayne

I didnt think that sketch would fly.
If I were to

So this is a basement, with a concrete slab, but the 4" branch is just below the slab, not, say, 6" clear below the slab?

Then you either route the lav drain behind the WC to come hit the shower drain first (the length of the lav drain/wet vent is not limited, while the shower trap arm is limited). Or you dry vent the shower.

To dry vent the shower you need to route the shower drain under or next to a wall in which you can pull off the dry vent vertically and stay vertical. The diagram you posted is no longer allowed as the dry vent can't go horizontal until 6" above the fixture flood rim.

Cheers, Wayne

Yes the 6" rule...
To clarify.
Would I be able to run the shower drain to a wall, place the p trap under the wall and connect it to the dry vent there. Then run the drain from the p trap to drain the shower flow to the 4".

 

[Reach4]

The U of the P-trap would not be under the wall. The trap arm would go to the wall, get vented, and then turn whichever way you want to go after being vented.

Use 3 inch instead of 4 inch to reduce height.

Instead, can you run the lavatory drain pipe over the 3-inch, join the shower trap arm with a wye (thereby wet-venting the shower). Then the output of that junction wyes into the 3 inch.