# Blackbeard

• posted on July 19, 2004, 4:05 pm
BB, What I'm saying is this guy wants to use a 1 1/2" Vent for a WC. The WC is 3", you need to replace a 3" water slug with a equal amount of Air or you create lower pressure or what many call a vacuum. This makes no sense unless there is some proof this works. This water first enters the 3" line pushing air ahead of it then an equal amount of air must replace the water. Not doing this will upset the +/ - 1" of atmospheric pressure needed to balance the P traps in the Lav.
Hell, why not use a 1/4" vent line ? All you need is an air compressor.
The Code is Law when the word ' Shall ' is in that part. The Code has allot of ' Mays ' and ' Shoulds ' in it. May, is to ask permission and Should, means its up to you.
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<%-name%>
• posted on July 20, 2004, 4:25 am

I'm coming in on the middle of the conversation here. Do you mean that a toilet needs a 3" vent?
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<%-name%>
• posted on July 20, 2004, 4:51 am
I *would run 3" if I could I'm not cheap on materials, but no, Mike. 2" before VTR. We know there is far more than a simple statement saying this. I just say physics says no to 1 1/2". I have the math, I can post it later. Air pressure is the most important thing in venting. You must maintain the +/-1" in P traps for balance. 144p=w h
I say no also due to the cold weather in CO as it could block the vent in 24 hrs depending on temp. I say no as a bird could block that small vent for the Lav. I say no as I would not want to go back and tear out the walls if they have venting problems.
Its his buisness, he says it will save him money. Ok.

a
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<%-name%>
• posted on July 20, 2004, 10:01 am
thats a lot of what ifs? so in a back to back you would need a six inch vent?
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<%-name%>
• posted on July 20, 2004, 12:57 pm
huh? My code still says one 3" in a dwelling.

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<%-name%>
• posted on July 22, 2004, 12:24 pm
"jim donovan"

At the restaurant, they'll need a 12" vent! Wow!
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<%-name%>
• posted on July 23, 2004, 6:27 pm
mike grooms if they are wall hung toilets (4 inch waste) you would need a 16 inch vent ,dbl wow but only one 3 inch vtr. i wonder who makes a 16 inch studor vent?
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<%-name%>
• posted on July 22, 2004, 12:22 pm
Well OK. The picture you painted was that of a 3" pipe totally filled with water, and then pulling a perfect vaccum. The water gets all spread out, and in a stack, it adheres to the sides of the pipe. The way you were making it sound was that you'd need a 3" vent to replace the air so that the sink trap would be protected. No wonder I was wondering.
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<%-name%>
• posted on July 22, 2004, 3:45 pm
I never meant it that way. Some don't know that fluids *swirl in a Hoz. line a short distance from initial start point. If in a stack over 3 floors or 30', fluids stops and equals gravity and a slug of fluid falls over the stopped slug and all slugs still have 7/24 of Air in its center, this is what makes for the air balance in the P traps +/- 1". 7/24 is a constant.
So, in a stack; I mean that a 7/24 of 3" is larger than 7/24 of 1 1/2 " So, there is less chance of self siphoning.
In a Hoz. line that goes into a T then a Stack, the fluid will not hit the opposite side of the inside Stack line. ( gravity conditions) Providing the Hoz. is equal or less then the Stack size. So, even here there is air. Its the volume of air to be concerned about for balance. Size matters.
Just like in, ' Bob's male enhancement ' commercials.

were
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<%-name%>
• posted on July 22, 2004, 6:27 pm
size does matter,but the reason Bob is smiling is that he has not read your last post. jp@yahoo
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<%-name%>
• posted on July 22, 2004, 7:04 pm
Hey, that shit works. That's why I step on my dick.

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<%-name%>
• posted on July 23, 2004, 12:34 am
The way these things are figured is to look at the charts in the applicable code book. They've assigned fixture units for various fixtures. You look at the load, calculate the appropriate developed length, and see which size pipe to run. By these figures, for example, if there's a full bath, you can vent a bathtub with 1.5", vent the toilet with 2", and even wet vent it with a lav. It works just fine. You tie these vents together and run them to the vent stack (or stack vent). Now if you want to run 3", it's OK. I guess you could run 4", but it won't work any better.
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<%-name%>
• posted on September 12, 2004, 6:11 pm
guess you want to ignore what you have seen yourself.

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<%-name%>
• posted on September 15, 2004, 10:13 pm
I suspect you'll find that air flows through PVC easier than liquids. So, the smaller vent line would work OK.
Warning: I am not a plumber!
--
Christopher A. Young

Do good work.
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<%-name%>
• posted on September 16, 2004, 10:02 am
Nor am I. I'm a Plummer.

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<%-name%>
• posted on October 16, 2004, 3:11 am
"Stormin Mormon"

Gee, why not just draw a bullseye on your chest?
I think I'll surf over to alt.medicaldoctors and tell them which EEG machine I like best., or how I think an MRI should be done.
Now go back to one of your wives and repent.