Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > Plumbing

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Reply
 
Thread Tools Search this Thread Display Modes
Old 01-14-2009, 04:03 PM   #1
Member
 
Join Date: Nov 2007
Location: Appleton, Wisconsin
Posts: 935
Rewards Points: 500
Default

Venting


I'm trying to get a better understanding on venting. I understand drains-crap runs down hill but don't really get venting. I understand the purpose of venting and get the basics of it but can someone explain some of details of it. Like some guidelines on sizing and how far from a fixture the vent can be? Like how to vent a shower/bath tub? A washing machine? Toilet? Do you just need one vent and tie everything into this in the attic? If you have a two story house can you run the vent from the kitchen over to the main stack on the first floor or would this be wet venting?

I'm going to be remodeling the bathrooms in my house and eventually the kitchen so i am trying to do some homework to do some pre planing and make sure my framing and what not will allow for proper venting. I bought a couple books on plumbing but they weren't really clear so thanks for any help with this.

ponch37300 is offline   Reply With Quote
Old 01-14-2009, 04:27 PM   #2
Member
 
Join Date: Jun 2008
Posts: 1,264
Rewards Points: 500
Default

Venting


The toilet doesn't get vented. It discharges directly into the vent stack, which is the main pipe that all the other vents connect to. In the event that you add a toilet in your basement rec room, then the plumbing code won't require that you provide venting for it because that would require cutting big holes in the walls of your house up to the roof to put in an auxilliary vent stack. In a case like that, the code only requires that you connect the toilet's floor flange to the main drain line from the building.

The drain pipe diameters needed and the distance vent connections can be from the drains is best gotten directly from your local plumbing inspector's office. Normally they'll have a kiosk there with brochures with drawings outlining do's and don't of drain pipe and vent connections. Phone ahead to make sure they have such brochures to ensure you don't make the trip for nothing. Typically, the code will require a 1 1/4 inch drain for the sink, a 1 1/2 inch drain for the bathtub and a 3 inch drain pipe for the toilet. But, if it wuz me, I'd use 1 1/2 for both sink and tub.

Also, if you have the option, run 3/4 inch lines from your cold and hot water supplies to the bathroom, and tap off of each 3/4 inch pipe with 1/2 inch diameter pipes to each fixture. Since a 3/4 inch supply pipe can supply full water flow to two 1/2 inch pipes simultaneously, there won't be any change in temperature in the shower if someone flushed the toilet in the other part of the bathroom.

The purpose of venting is apparant to anyone who's ever been in a subway station. When the subway train leaves the station, you get a strong wind into the tunnel behind it. Similarily, water draining down a drain pipe can create a partial vaccuum behind it. This partial vaccuum can be strong enough to suck the water out of the p-traps below your sinks and bathtub. If that happens, then sewer gas can come into your house through those empty traps making your bathroom smell like an outhouse.

The purpose of a vent is to allow air to rush into the drain pipe whenever there's a partial vaccuum at the vent pipe connection. That quenches the vaccuum and prevents the water from being sucked out of the p-trap. Thus, the vent connection has to be at the upstream end of the drain pipe, but still downstream of the p-trap.

Sometimes you really can't connect a vent to a drain pipe. For example, if you have a sink on a kitchen counter top island, you don't want to see a vent pipe coming out of that counter top surface and going up into a hole roughly cut in the ceiling. In a case like that, you'd use an AIR ADMITTANCE VALVE instead of a vent pipe. An air admittance valve is nothing more than a big plastic check valve with a weak spring holding it closed. Any time there's a sufficiently strong partial vaccuum in the drain pipe, the air admittance valve on the drain pipe opens against spring pressure to allow air into the drain pipe so that the partial vaccuum doesn't suck the water out of the p-trap. Thus, the air admittance valve would connect to the drain piping roughly where the vent would, but would be out of sight so as not to mess up the appearance of the kitchen.

__________________
Bashing my head against the walls in some of the internet's finest chat rooms.

Last edited by Nestor_Kelebay; 01-14-2009 at 09:02 PM.
Nestor_Kelebay is offline   Reply With Quote
Old 01-14-2009, 04:54 PM   #3
Member
 
Join Date: Dec 2008
Location: South Western Ontario
Posts: 955
Rewards Points: 500
Default

Venting


Nestor, I have 3 toilets which are low flush all the same brand, valve, etc.
The best performing of the 3 vents directly into the 3" stack behind it in my ensuite. Seldom if ever an issue.
The other two are vented main floor via a sink vent branch up to the 3" main in the attic and upstairs via a 1 1/2" stack in an outside wall tied intro the 3" main stack in the attic.
Could these narrow vents be the likely cause of continuous plunging requirements on the other 2 toilets ? Is the venting more significant since I have upgraded to low flush?
Chemist1961 is offline   Reply With Quote
Old 01-14-2009, 05:19 PM   #4
Member
 
Join Date: Jan 2009
Location: Long Island
Posts: 348
Rewards Points: 250
Default

Venting


can help you a lot better if show us the plans and be careful what you read here, I just read a good one. Meant well but omg
II Weeks is offline   Reply With Quote
Old 01-14-2009, 07:35 PM   #5
Member
 
Join Date: Nov 2007
Location: Appleton, Wisconsin
Posts: 935
Rewards Points: 500
Default

Venting


Thanks guys. So would i just run the drain from the sink and other fixtures into a trap and then into the wall and drain goes down and vent straight up and then tie everything together in the attic? Lets say i have a wet bar in the basement, can i vent into the main stack or is this considered wet venting? And would i have to run this vent up to the attic to tie into the main stack?


And lets say a kitchen sink with a window above it, do i just run the drain into the wall and then drain down and vent over then up to the ceiling and then tie into the main stack? Sorry for all the questions but just trying to make sure that i understand everything. Thanks again
ponch37300 is offline   Reply With Quote
Old 01-14-2009, 09:35 PM   #6
Member
 
Join Date: Jan 2009
Location: Long Island
Posts: 348
Rewards Points: 250
Default

Venting


without seeing any plans I'll just through this out there for you. The last three bathroom house we worked on had three vents through the roof around the home. You do what you have to. Under the sink you could install a pro-vent after the trap or run a vent from there just following the drain and so on and so on. Hard to help in the blind here but I will add that wet venting is really discouraged.
II Weeks is offline   Reply With Quote
Old 01-14-2009, 10:06 PM   #7
Member
 
Join Date: Jun 2008
Posts: 1,264
Rewards Points: 500
Default

Venting


Quote:
Originally Posted by Chemist1961 View Post
Nestor, I have 3 toilets which are low flush all the same brand, valve, etc.
The best performing of the 3 vents directly into the 3" stack behind it in my ensuite. Seldom if ever an issue.
The other two are vented main floor via a sink vent branch up to the 3" main in the attic and upstairs via a 1 1/2" stack in an outside wall tied intro the 3" main stack in the attic.
Could these narrow vents be the likely cause of continuous plunging requirements on the other 2 toilets ? Is the venting more significant since I have upgraded to low flush?
Chemist:

I'm probably not a good person to talk to about "toilet venting". My understanding is that the plumbing code in Manitoba (where I live) may be different than other localities because we NEVER connect any other plumbing fixture to the same drain pipe that the toilet discharges into.

Here in Winnipeg, where I live, the plumbing code requires that the toilet be within 10 feet of the vent stack it discharges into, unless you're adding a toilet in the basement of an existing house. In that case, the toilet can be anywhere. You just connect it's floor flange to the main drain line from the house, and that's it. No venting requirement.

Also, up until about 20 years ago when PVC and ABS came along, toilets here in Winnipeg were installed using "lead bends", which is a 4 inch diameter lead elbow weighing about 50 pounds. You cut a 5 inch diameter hole in the floor, pushed one end of the lead bend up through that hole and used oakum and something called a "wiped" solder joint to connect the other end of the lead bend into a hub in the cast iron vent stack using a brass ferrule. The other end of the lead bend would be heated with a torch and pounded out with a hammer to flare out over a brass floor flange screwed to the floor.

I have a 21 unit apartment building, and approximately 19 lead bends (two of which have been replaced with plastic) and none of those toilets are "vented". In every case, there are 1 1/2 inch "bungalow" fixtures on the vent stack that provide both a 3 inch hub (for the toilet) and a 1 1/2 inch threaded hole (for the sink and tub drains). Thus, both the toilet drain pipe and the 1 1/2 inch drain to the sink and tub connect to the same "Bungalow" fixture on the vent stack.

Consequently, it has been my understanding until now that toilets aren't vented. But, I just tried Googling "toilet venting" and found lots of references to it, so there has to be a basic difference in the plumbing codes that requires it there, but not here in Manitoba.

Maybe it's because our toilet drain lines are always short, and no other plumbing fixtures that would normally need to be vented are ever connected to the same drain line as a toilet.

Sorry I couldn't have been more help.

In the following web page, a ceramic tiling contractor who was apparantly not familiar with lead bends cut it just like a cast iron or plastic pipe. That is, just above the tile height so that a plastic floor flange could be cemented into it. (He didn't realize that a brass floor flange would be dropped over that lead pipe sticking out of the floor, the lead pipe cut shorter and then flared out over the brass floor flange.)

http://www.askmehelpdesk.com/plumbin...nge-53065.html

Lead bends are common in Manitoba, and I can't imagine how you could even vent one.
__________________
Bashing my head against the walls in some of the internet's finest chat rooms.

Last edited by Nestor_Kelebay; 01-14-2009 at 10:18 PM.
Nestor_Kelebay is offline   Reply With Quote
Old 01-14-2009, 10:21 PM   #8
Member
 
Join Date: Jun 2008
Posts: 1,264
Rewards Points: 500
Default

Venting


Quote:
Originally Posted by ponch37300 View Post
Thanks guys. So would i just run the drain from the sink and other fixtures into a trap and then into the wall and drain goes down and vent straight up and then tie everything together in the attic? Lets say i have a wet bar in the basement, can i vent into the main stack or is this considered wet venting? And would i have to run this vent up to the attic to tie into the main stack?


And lets say a kitchen sink with a window above it, do i just run the drain into the wall and then drain down and vent over then up to the ceiling and then tie into the main stack? Sorry for all the questions but just trying to make sure that i understand everything. Thanks again
The bar sink in the basement and the sink in front of a window are good places to use an air admittance valve instead of a vent pipe.
__________________
Bashing my head against the walls in some of the internet's finest chat rooms.
Nestor_Kelebay is offline   Reply With Quote
Old 01-15-2009, 07:10 AM   #9
Member
 
Join Date: Dec 2008
Location: South Western Ontario
Posts: 955
Rewards Points: 500
Default

Venting


Thanks Nestor, didn't mean to hijack the post

Given the history of heaving in River Heights / Osborne and the freeze etc, I can understand the difference in codes in Winterpeg. I have seen those lead bends...

My question was meant to be more general ...3" versus 11/2"flushing ability on a low flow toilet anywhere. I thought this might be a relevant question given the reno posted. Given how a gas can vents I assume the 3" stack would give a boost to any toilet, especially a low flow....
Chemist1961 is offline   Reply With Quote
Old 01-15-2009, 07:37 AM   #10
Member
 
Join Date: Nov 2008
Posts: 113
Rewards Points: 75
Default

Venting


1 1/2" vent is sufficient for a 3" toilet line, I vent every fixture, wether it be with one wet vent for an entire fixture group( toilet, lav, tub) or seperate dry vents for toilet and tubs. you can't go wrong with having extra vents, better flow in the lines.
zosoplumber is offline   Reply With Quote
Old 01-15-2009, 04:57 PM   #11
Member
 
Join Date: Nov 2007
Location: Appleton, Wisconsin
Posts: 935
Rewards Points: 500
Default

Venting


Thanks for all the help guys. I think i understand most of it now. I made a little drawing(I'm definitely not an artist!) of a two story house with a toilet on each level by the main stack. Then the kitchen sink on the other side. When i vent the kitchen sink can i tie into the main stack in between the 1st floor and 2nd floor or is this considered wet venting and not good? Should i just run the sink vent up to the attic and tie into the main stack above all the drains? Also if i have a sink in the 1st floor bathroom how would i vent that? Can i tie it into the main stack on the 1st floor or would this also be wet venting? Or do i have to run this all the way up to the attic and tie into the main stack above the drains for the 2nd floor fixtures? Thanks again for your knowledge
Attached Thumbnails
Venting-venting.jpg  

Last edited by ponch37300; 01-15-2009 at 05:47 PM.
ponch37300 is offline   Reply With Quote
Old 01-15-2009, 06:20 PM   #12
Member
 
Join Date: Jan 2009
Location: Long Island
Posts: 348
Rewards Points: 250
Default

Venting


I wouldnt vent the kitchen sink to the main vent line. Install one of these instead. Theyre legal in most places. Safe and easy to install.
Attached Thumbnails
Venting-air-inlet-valve-ii_w550.jpg  
II Weeks is offline   Reply With Quote
Old 01-15-2009, 06:21 PM   #13
Member
 
Join Date: Jan 2009
Location: Long Island
Posts: 348
Rewards Points: 250
Default

Venting


heres another option for venting an island sink. little harder
Attached Thumbnails
Venting-islandvent3.jpg  
II Weeks is offline   Reply With Quote
Old 01-15-2009, 08:51 PM   #14
Member
 
Join Date: Nov 2008
Posts: 113
Rewards Points: 75
Default

Venting


darn right, studer vents are great, never had a probrlem with drainage, and compare the cost and time it will take to run the vent and i bet you'll go with a mechanical vent
zosoplumber is offline   Reply With Quote
Old 01-16-2009, 12:00 AM   #15
Member
 
Join Date: Jun 2008
Posts: 1,264
Rewards Points: 500
Default

Venting


Quote:
Originally Posted by II Weeks View Post
I wouldnt vent the kitchen sink to the main vent line. Install one of these instead. Theyre legal in most places. Safe and easy to install.
Your drawing shows a 22 1/2 degree elbow on a 1 1/2 inch drain line.

I understand that you might need a 45 to get the vent vertical. My point is that I've never seen a 22 1/2 degree elbow in the smaller plastic pipe sizes like 1 1/2 inch. Do they exist?

__________________
Bashing my head against the walls in some of the internet's finest chat rooms.
Nestor_Kelebay is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Furnace venting questions Mastiff HVAC 9 12-05-2012 06:51 PM
venting metal roof for attic conversion nelsonC Roofing/Siding 14 01-21-2010 03:32 AM
Addition Question: venting roof/crawlspace supton Building & Construction 6 01-22-2009 07:33 PM
repair furnace venting diybrian HVAC 2 12-29-2008 08:56 AM
Blocked Attic Soffit Vents on North Side - How to Improve Venting Jes Roofing/Siding 5 05-06-2008 10:35 AM




Top of Page | View New Posts

Copyright © 2003-2014 Escalate Media. All Rights Reserved.