Distance from the tub drain to the vent UPC code

[Twowaxhack]

The idea is to treat everything 6” above the flood level rim and below as drainage and everything above as the vent system.

So the vent system would be the only exception where a sanitary tee could be laid down. In the drainage system it can only be allowed to stand up.

If the piping has the possibility to be flooded at any point, like a blockage in the system, then it’s considered the drainage system even if it’s a dry vent.

It’s similar to the rule about a flat vent below the floood level rim that’s not washed by a fixture, it’s not allowed because solids can back up into that portion and block the vent. They want you 45 degrees or more to be considered vertical but you still have to use long sweep fittings

It’s been said The sweep of a sanitary tee on its back isn’t great enough to allow the pipe to clear itself of solids when in a vertical position.
This could be a problem in a revented situation where you had no access to clear the vent.

Drain cables do not like making the transition from vertical to horizontal through a san tee on its back, this is especially true with 3”-4” pipe.

I’m not saying I agree with all of this, I’m just trying to give an explanation as to why it’s not legal to do in all jurisdictions.

The only way I lay San tees down is when I have no room for long sweep fittings and it would weaken the structure to make them fit without expensive structural work. But I always make provisions for great cleanout access when I do. Rare occasions.

 

[user 32496]

love the answer, unfortunately got a pregnant wife that needs the tub operational lol but i am tempted to go this way just for fks of it. All i hear is horror stories about local inspectors. No wonder nobody wants to get permits. I was the only idiot that decided to do everything by the book and now paying for it...

That’s why I don’t like getting the government involved in my projects.

 

[Twowaxhack]

That’s why I don’t like getting the government involved in my projects.

I know a plumber who use to make a mud hole outside the crawlspace entrance when in a certain inspectors area. No, it wasn’t me.

This inspector caused the city to lose several lawsuits due to his mistakes. I filed and won a lawsuit against the jurisdiction. This inspector would fail jobs and wouldn’t state the violation. He would also try to enforce what he wanted rather than what the law (code) stated. He did so knowingly.

My lawsuit prevented him from becoming chief inspector and shortly after he was fired for littering. He threw a banana peel out of his city vehicle in the middle of the business district and the mayors wife was behind him.

When he was told a lady called the complaint in, he called her “ a lying ***** “ and that was the end of him. Word on the street was he had a discipline folder a foot thick.

 

[MicEd69]

The Uniform Plumbing Code (UPC) does not specify a specific distance requirement between the tub drain and the vent. Rather, it provides guidelines for the proper venting of plumbing fixtures to ensure proper drainage and to prevent traps from being siphoned or losing their seal.

According to the UPC, the general rule is that every trap should be protected by a vent. The vent should be sized and located in a way that allows for the free flow of air to prevent the formation of a vacuum or positive pressure within the plumbing system.

The specific requirements for venting distances and configurations may vary depending on the jurisdiction and local plumbing codes. It's important to consult with your local building department or a licensed plumber to determine the specific requirements and regulations for your area.

A licensed plumber or plumbing professional will be familiar with the local codes and can provide guidance on the appropriate distance and configuration for the vent in relation to the tub drain. They will ensure that the plumbing system is properly designed and installed to meet the code requirements and to ensure the efficient and safe operation of the plumbing fixtures.

I'm in an IPC area and don't have a copy of UPC. But according to NUMEROUS references on the internet, UPC does have listed maximum lengths. If you have a UPC book, check T10-1. IPC uses strict geometry to figure the vent opening, while UPC adds a safety factor for minor slope installation inaccuracies.

 

[user 32496]

The Uniform Plumbing Code (UPC) does not specify a specific distance requirement between the tub drain and the vent. Rather, it provides guidelines for the proper venting of plumbing fixtures to ensure proper drainage and to prevent traps from being siphoned or losing their seal.

According to the UPC, the general rule is that every trap should be protected by a vent. The vent should be sized and located in a way that allows for the free flow of air to prevent the formation of a vacuum or positive pressure within the plumbing system.

Huh? My copy of 2012 UPC says this...

1002.0 Traps protected by Vent pipes.
1002.1 Vent pipes. Each plumbing fixture trap, except as otherwise provided in this code, shall be protected against siphonage, backpressure, and air circulation shall be assured throughout the drainage system by means of a vent pipe installed in accordance with the requirements of this
code.
1002.2 fixture Traps. Each fixture trap shall have a protecting vent so located that the developed length of the trap arm from the trap weir to the inner edge of the vent shall be within the distance given in Table 1002.2, but in no case less than two times the diameter of the trap arm.



IPC says this:
SECTION 909 FIXTURE VENTS
909.1 Distance of trap from vent. Each fixture trap shall have a protecting vent located so that the slope and the developed length in the fixture drain from the trap weir to the vent fitting are within the requirements set forth in Table 909.1.
Exception: The developed length of the fixture drain from the trap weir to the vent fitting for self-siphoning fixtures, such as water closets, shall not be limited.




A county specifies what code they use, ie UPC or IPC, and what year. A county may not necessarily use the latest version on the code. My County uses 2006 IPC with local amendments (none).

So I guess, the OP should google what code (and year) his county uses, But what year UPC are you quoting that says, "The Uniform Plumbing Code (UPC) does not specify a specific distance requirement between the tub drain and the vent"?

 

[user 32496]

I'm in an IPC area and don't have a copy of UPC. But according to NUMEROUS references on the internet, UPC does have listed maximum lengths. If you have a UPC book, check T10-1. IPC uses strict geometry to figure the vent opening, while UPC adds a safety factor for minor slope installation inaccuracies.

View attachment 42362

That's a nice picture. I guess I was writing a post the same time you were! LOL

 

[Twowaxhack]

Here’s the questions to ask.

Does my local jurisdiction have a minimum size trap for a bathtub ? We have to use 2” for tubs.

Does the location of the trap dictate in any way what size trap I must use ?
We have to use 2” under slabs.

What does my jurisdiction allow for trap to vent distances ? We use IPC with amendments but can get a variance if you ask and can show a just cause. Inspector can approve anything that’s not a health/safety hazard.

Looking at the table it shows fixture arm length aka distance from trap weir to vent. It doesn’t specify what fixtures.


There are exceptions to almost everything in the book depending on the situation and over the years codes change. This is why some of the tests are open book and allow calculators. They want to know that the applicant knows how to use and interpret the codebook on the job site to figure out problems.

Some inspectors will not answer code questions, they won’t even explain the code, it’s your job to know they say. I believe you can still buy a book that explains the reasoning and clarify what some of the intent of the code is. They had to come up with that because some of the plumbers and inspectors had way different interpretations and it causes huge fights on the job site at inspection time.

Often we get paid by customers when inspections are passed. That’s how I write my contracts, X amount due immediately upon inspector approval…..yadda yadda yadda

So if you don’t pass inspection it means you’re not getting paid.

 

[user 32496]

Hi guys, need some assistance to "decipher" the UPC code used in state of WA
I think i have created a bit of a painful situation for myself because i misread the IPC/UPC code.

I have an existing tub drain connection with a 1 1/2 p-trap that continues into the 2 inch trap arm about 40 inch long in total from the drain to the vent (2 inches down to ground floor and 1 1/2 up to the attic for vent). ( see pic attached ) (the metal cylinder next to the vent is the B Vent from my furnace and water heater)

By UPC code i can have 5 ft distance from vent to drain flange if the trap arm is 2 inch wide, but only 3.5 if its 1 1/2.

As I've mentioned before, I don't like getting the government involved with my projects but it sounds like you have already gone down that road.

Even though I don't consult the government on my projects (anymore than they consult me on their projects), code is there to protect you and is worth abiding by if it makes sense. The trap arm distance is there to protect you from sewer gasses as mentioned in many posts above...but UPC code puts quite a conservative amount of protection in there. My county goes by IPC which will allow 8' from the trap to the vent opening with a 2" diameter trap arm. If your slope is exactly 1/4" per foot of drop, 8' will work fine. If your slope is greater than 1/4" per foot, then the distance becomes less when a siphon will form...it's physics. I personally would be okay with your 65" on a 2"Dia trap arm if the slope is at 1/4" per foot. It will work the way it should. Getting it to pass inspection is another issue confirming why I don't like to get the government involved.

Having said all that, I too have questions about the 1 1/2" trap on a tub/shower. Can that be changed to a 2" on your new tub?

 

[Twowaxhack]

I’ve ran a shower drain 40’ flat (no fall ) on 2” with a 2” trap.

It’s still working and it’s been there 25 years. It’s draining perfect and always has.

Go out and try to fill up a flat laid 2” drain pipe enough for it to back up. You’ll need a fire hose to accomplish it.

 

[user 32496]

I’ve ran a shower drain 40’ flat (no fall ) on 2” with a 2” trap.

It’s still working and it’s been there 25 years. It’s draining perfect and always has.

Go out and try to fill up a flat laid 2” drain pipe enough for it to back up. You’ll need a fire hose to accomplish it.

Well, let's see... If 8' works with a 1/4" drop, then 16' is good for 1/8" drop, 32' for 1/16th" and 64' for 1/32nd" per foot drop. You could have used a 1/32nd" per foot drop and been okay!

 

[MicEd69]

Well, let's see... If 8' works with a 1/4" drop, then 16' is good for 1/8" drop, 32' for 1/16th" and 64' for 1/32nd" per foot drop. You could have used a 1/32nd" per foot drop and been okay!

As an engineer, I've used Machinist Levels that must be maintained at an ambient temperature after calibration and have to be recalibrated often if changes in temperature occur. They can't even be set of machines for more than a few seconds if the machine temperature is not that of the level itself. I doubt any plumber's level could reliably produce 1/32nd of an inch for 64 ft.

But I get your point! LOL.

 

[Twowaxhack]

I use a Bosch laser level that’s pretty accurate. +~ 1/8” accuracy over 100 feet.

 

[MicEd69]

Not bad. Not 0.05" in 100 feet, but not bad.

 

[user 32496]

As an engineer, I've used Machinist Levels that must be maintained at an ambient temperature after calibration and have to be recalibrated often if changes in temperature occur. They can't even be set of machines for more than a few seconds if the machine temperature is not that of the level itself. I doubt any plumber's level could reliably produce 1/32nd of an inch for 64 ft.

But I get your point! LOL.

The easy way would be to lower the end of the 2” pipe 1 3/4”…which would be close to the maximum 2” drop before a siphon could set up. What ever angle that forms would be okay.

 

[MicEd69]

The easy way would be to lower the end of the 2” pipe 1 3/4”…which would be close to the maximum 2” drop before a siphon could set up. What ever angle that forms would be okay.

Now if you can just keep that squirrelly pipe absolutely straight for 64 feet without any bellies, your all set. LOL.

 

[user 32496]

Now if you can just keep that squirrelly pipe absolutely straight for 64 feet without any bellies, your all set. LOL.

Yes! The 1/4” per foot drop actually is much easier.

 

[Twowaxhack]

Most sewers have a belly or two. A lot of plumbers buy the $6k camera to show the customer the imperfections found in almost all sewer lines in order to help sell dig jobs, because that’s where the real money is.

Even more so when the camera job is “ free “ when they clean a sewer.