Venting Questions

1K2GO · 12-29-2007, 08:09 PM

I am doing the plumbing myself in the new house that i am building and i have a few venting questions.

I have a 3" "wet vent" running from the basement bathroom up. How many fixtures can i tap onto that vent with? I am wanting to do 3 toilets, 3 bathroom sinks, 2 tubs, and a kitchen sink. Is this ok?

USP45 · 12-29-2007, 08:22 PM

You say this is a wet vent. A wet vent is a horizontal line that is sized larger than needed so as to let air flow across the top of the water. This line sounds as if it is vertical. If it is and goes out through the roof then you can attatch as many as you want. I have installed all the fixtures into 1 common vent with no trouble. And the only thing you need is a vent thats 1/2 the building drain, such as 3" main = 1-1/2" vent, 4" main = 2" vent. Also even if waste is ran through the vertical lines all you have to do is install the vents as high up as you can and you'll be fine (Above the ceiling line)

jpplumber · 12-30-2007, 12:35 AM

Quote:

You say this is a wet vent. A wet vent is a horizontal line that is sized larger than needed so as to let air flow across the top of the water.

I believe this describes a flat vent.

The drain portion of a pipe is where the water flows through a horizontal pipe and also down a vertical pipe. The vent portion of a pipe is for air flow. A wet vent is a portion of piping that has been run for at least two fixtures that are using the same vent and one fixture is higher than the other; the portion between where the two drains tie into the vent is the wet portion of the vent.

A 3" horizontal drain can accommodate no more than 2 toilets.

Vent each fixture and the 3" vertical drain should accommodate the total fixture units; but somewhere after the vertical drop (in the basement) the line will be horizontal again so run 4".

It has been a few years since I took my test and I never do rough work so someone who loves code books can let me know

or

jpplumber · 12-30-2007, 12:43 AM

Here is a good picture some one provided on a previous thread.

ranman469 · 12-30-2007, 09:11 AM

the bad thing is code differs from state to state, and city to city.
the guys here really know their stuff

but there are big diffrences throught the country.
best bet. draw a pic of what you have and what you want to do then post it. so we all are on the same page of what you want to do.
in michigan 3 w/c`s on a 3" stack the code is Ipc
in az. no more than 4 w/c`s on a 3"vertical or horz

Ron The Plumber · 12-30-2007, 10:38 AM

UPC says you can't wet vent unless you increase the size of the vent one pipe size larger then the fixture it will serve. Wet venting allowed only on the same floor it serves.

Example, here, I run my shower drain pick up the vent for it using a drainage fitting, and I want to tie a lav sink into the vent, since the vent for a shower only needs to be 1-1/2" and the drain for a lav is min 1-1/4", for me to wet vent the shower I have to increase the vent that serves the shower to 2", then connect the sink into the 2" vent of the shower, then after I tie it in I can now decrease the vent above the sink tie in to 1-1/2"

So as you see as long as it's on the same floor and you increase the vent one size then the upper most fixture, wet venting is allowed.

Here a wet vent that is serving a bottom floor can not be used to serve the second floor.

Confused, yes it can get that way.

12-29-2007, 08:09 PM	#1
1K2GO Newbie Join Date: Sep 2007 Posts: 15	Venting Questions I am doing the plumbing myself in the new house that i am building and i have a few venting questions. I have a 3" "wet vent" running from the basement bathroom up. How many fixtures can i tap onto that vent with? I am wanting to do 3 toilets, 3 bathroom sinks, 2 tubs, and a kitchen sink. Is this ok?

12-29-2007, 08:22 PM	#2
USP45 Building and plumbing Join Date: Dec 2007 Location: farmville, VA Posts: 244	Venting Questions You say this is a wet vent. A wet vent is a horizontal line that is sized larger than needed so as to let air flow across the top of the water. This line sounds as if it is vertical. If it is and goes out through the roof then you can attatch as many as you want. I have installed all the fixtures into 1 common vent with no trouble. And the only thing you need is a vent thats 1/2 the building drain, such as 3" main = 1-1/2" vent, 4" main = 2" vent. Also even if waste is ran through the vertical lines all you have to do is install the vents as high up as you can and you'll be fine (Above the ceiling line) Last edited by USP45; 12-29-2007 at 08:25 PM.

12-30-2007, 12:43 AM	#4
jpplumber Master Plumber Join Date: Jan 2007 Location: Texas Posts: 169	Venting Questions Here is a good picture some one provided on a previous thread.

12-30-2007, 09:11 AM	#5
ranman469 Member Join Date: Dec 2007 Posts: 85	Venting Questions the bad thing is code differs from state to state, and city to city. the guys here really know their stuff but there are big diffrences throught the country. best bet. draw a pic of what you have and what you want to do then post it. so we all are on the same page of what you want to do. in michigan 3 w/c`s on a 3" stack the code is Ipc in az. no more than 4 w/c`s on a 3"vertical or horz

12-30-2007, 10:38 AM	#6
Ron The Plumber Journeyman Plumber Join Date: Jun 2006 Location: Eugene, Oregon Posts: 1,994	Venting Questions UPC says you can't wet vent unless you increase the size of the vent one pipe size larger then the fixture it will serve. Wet venting allowed only on the same floor it serves. Example, here, I run my shower drain pick up the vent for it using a drainage fitting, and I want to tie a lav sink into the vent, since the vent for a shower only needs to be 1-1/2" and the drain for a lav is min 1-1/4", for me to wet vent the shower I have to increase the vent that serves the shower to 2", then connect the sink into the 2" vent of the shower, then after I tie it in I can now decrease the vent above the sink tie in to 1-1/2" So as you see as long as it's on the same floor and you increase the vent one size then the upper most fixture, wet venting is allowed. Here a wet vent that is serving a bottom floor can not be used to serve the second floor. Confused, yes it can get that way. __________________ Fix it right the first time, so you won't have to fix it a 2nd time. To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Venting Questions