Does this plan look Okay? Any help appreciated!

[argoskier]

That's true for the UPC, but Vermont uses the IPC, so unless I missed some additional information, that wouldn't apply to the OP.

IPC just requires the vent to be at least half the size of the drain, and large enough for the DFUs. So if the building drain is 3", it would allow 1-1/2" vents. Of course, Vermont is a cold climate, so from the building thermal envelope up through the roof should be 3".

[I didn't review the rest of this thread.]

Cheers, Wayne

Thanks Wayne!

 

[Jeff H Young]

That's true for the UPC, but Vermont uses the IPC, so unless I missed some additional information, that wouldn't apply to the OP.

IPC just requires the vent to be at least half the size of the drain, and large enough for the DFUs. So if the building drain is 3", it would allow 1-1/2" vents. Of course, Vermont is a cold climate, so from the building thermal envelope up through the roof should be 3".

[I didn't review the rest of this thread.]

Cheers, Wayne

So a entire home can get by on a single vent1 1/2 out the roof in IPC code ? exception for frost

 

[Sponsor]

 

[argoskier]

While we are on the subject, I actually had a reducer fitting as the vent went out the roof, to turn it into 4". It seemed to me that being in the mountains, which can have super cold snowy winters, why not just go 4"?

 

[wwhitney]

So a entire home can get by on a single vent1 1/2 out the roof in IPC code ?

Sometimes, yes, unless I've overlooked something. This table in the IPC gives you the allowable length for a stack vent / vent stack based on vent size, soil or waste stack size, and DFUs:

Chapter 9 Vents: Vents, Alabama Plumbing Code 2021 | UpCodes

UpCodes offers a consolidated resource of construction and building code grouped by jurisdiction

up.codes

For example, you could have a 1-1/2" vent up to 32 ft in length serving a 3" soil or waste stack carrying up to 21 DFUs.

That doesn't explicitly address vents for building drains, but I don't see anything else in IPC 906 addressing that, so I would think it would be the same.

Cheers, Wayne

 

[Jeff H Young]

Do you still think the plan proposed in post #12 would work?

Yes I think it would work and since Im now enlightened on your plan dont really have any other great ideas. Increaseing vent size for frost /snow is pretty standard in cold areas like Vermont.

 

[Jeff H Young]

Sometimes, yes, unless I've overlooked something. This table in the IPC gives you the allowable length for a stack vent / vent stack based on vent size, soil or waste stack size, and DFUs:

Chapter 9 Vents: Vents, Alabama Plumbing Code 2021 | UpCodes

UpCodes offers a consolidated resource of construction and building code grouped by jurisdiction

up.codes

For example, you could have a 1-1/2" vent up to 32 ft in length serving a 3" soil or waste stack carrying up to 21 DFUs.

That doesn't explicitly address vents for building drains, but I don't see anything else in IPC 906 addressing that, so I would think it would be the same.

Cheers, Wayne

I cant find anything to disagree but thought UPC and IPC both had the same minimum out the roof on a single family home

 

[argoskier]

Yes I think it would work and since Im now enlightened on your plan dont really have any other great ideas. Increaseing vent size for frost /snow is pretty standard in cold areas like Vermont.

Thanks Jeff. Now I'm just wondering which side should be 3" and which side should be 2". I am leaning towards the pipe that has the bends in it to be 3", since it will be drawing more air than the vent with just the shower on it.

 

[wwhitney]

I cant find anything to disagree but thought UPC and IPC both had the same minimum out the roof on a single family home

Definitely no on that. The "vent area through the roof has to be at least the minimum building drain size" rule is UPC only.

Cheers, Wayne

 

[Jeff H Young]

Thanks Jeff. Now I'm just wondering which side should be 3" and which side should be 2". I am leaning towards the pipe that has the bends in it to be 3", since it will be drawing more air than the vent with just the shower on it.

Wayne is pretty good reaearching these codes us being in UPC arent so familiar but he suggests you only need a 1 1/2 and no 3 inch is even needed ? 1 1/2 or even 2 will fit in stud bay , we cant even vent a single toilet on 1 1/2 "

 

[argoskier]

Wayne is pretty good reaearching these codes us being in UPC arent so familiar but he suggests you only need a 1 1/2 and no 3 inch is even needed ? 1 1/2 or even 2 will fit in stud bay , we cant even vent a single toilet on 1 1/2 "

Hmmm, that's a good point. I'm just thinking that since the cost difference is pretty small compared to the price of the house I'm building, I'd just go with whichever is better...

question is, if it is any better to go with 3", or if it makes no difference at all...

 

[Jeff H Young]

Im So Prejudiced to my way of plumbing , I seldom run a 3 inch vent but we have multiple vents going through our roofs so there is plenty to breathe. We dont dream of 1 1/2 vents of toilets its a forieghn concept to us, let alone an entire bathroom or house.
I feel like its better to have more venting , how much better who knows ? Personaly Id run a 2 inch vent if my code allowed . maybe Id have a differant outlook if I was used to another system but cant really accept that IPC is good enough on this aspect , We want a little overkill to have a bullet proof (almost) system but withen reason.

 

[Tuttles Revenge]

Both of your drawings in #12 and #15 work. Just 15 is a bit more simple and less work. And an advantage that Whitney points out is that you can have all your vents go up in 1.5" and then the protrusion through the cold space needs to be upsized to account for the warm humid vent air freezing from the inside and constricting the vent opening.

 

[John Gayewski]

That's true for the UPC, but Vermont uses the IPC, so unless I missed some additional information, that wouldn't apply to the OP.

IPC just requires the vent to be at least half the size of the drain, and large enough for the DFUs. So if the building drain is 3", it would allow 1-1/2" vents. Of course, Vermont is a cold climate, so from the building thermal envelope up through the roof should be 3".

[I didn't review the rest of this thread.]

Cheers, Wayne

IPC is half of the pipe size nominally? Not cross sectionally?

 

[wwhitney]

IPC is half of the pipe size nominally? Not cross sectionally?

Yes. If you look at the link I posted, the preamble to that Table says " . . . but in no case shall the diameter be less than one-half the diameter of the drain served or less than 11/4 inches (32 mm)."

Cheers, Wayne

 

[argoskier]

Both of your drawings in #12 and #15 work. Just 15 is a bit more simple and less work. And an advantage that Whitney points out is that you can have all your vents go up in 1.5" and then the protrusion through the cold space needs to be upsized to account for the warm humid vent air freezing from the inside and constricting the vent opening.

Thank you for that. Very helpful!