Questions about horizontal wet venting

[codymccomber]

Following the UPC 2021

I am remodeling my bathroom. I am trying to wet vent my shower through the lavatory drain.

The horizontal wet vent is 2” and is going to be 66”, could be shortened to 60” if required. Then goes vertical approximately 18” where it meets with the sink and becomes a dry vent.

A couple questions:

1) Can the horizontal wet vent be 66” long? Not sure if horizontal vent follows similar code to a trap arm that is limited to 60” for 2”? 1002.2


2) For the shower, that is wet vented:
- Is the trap arm measured from the trap to where it connects to the wet vent?
- Or is the trap arm measured from the trap, through the wet vent, all the way to the vertical portion of the wet vent?


3) 908.1 Vertical Wet Venting: “no wet vent shall exceed 6 feet (72”) in developed length.”

Does this 6 feet limit only apply to the vertical portion of the wet vent? Or does it include the horizontal and vertical parts of the wet vent?

Meaning if the horizontal part of my wet vent is 66” then I only have an allowance of 6” vertical before the wet portion of the vent must end? Or if my horizontal wet vent is 60” then the vertical portion can be 12”?

Or is the 6 feet limit just the vertical wet vent?

 

[Tuttles Revenge]

Not sure which Washington you live in. If its Wash. State. Then you need to be following 2018 UPC with Wash. Amendments. The Wash. code amendments for horizontal wet venting removes the UPC requirement that the toilet be the Most downstream fixture in a HWV system.

You're going to install either a Horizontal Wet Vented system or a Vertical Wet Vent system... Each has their own set of rules and their own advantages and disadvantages.

HWV trap arm lengths must comply with the chart in 1002.2

 

[Sponsor]

 

[wwhitney]

1) The horizontal wet vent is unlimited in length.
2) The trap arm is from the trap outlet to the wye where the fixture drain joins the horizontal wet vent.
3) The 6' limit on Vertical Wet Venting does not apply to Horizontal Wet Venting, those are separate sections.

Cheers, Wayne

 

[GReynolds929]

Washington state adopted UPC 2021 with amendments on 3/15/2024

2021 Washington State Plumbing Code

epubs.iapmo.org

 

[Tuttles Revenge]

Washington state adopted UPC 2021 with amendments on 3/15/2024

2021 Washington State Plumbing Code

epubs.iapmo.org

Guess its time to get a new code book and add my 2018 to the archives.

 

[GReynolds929]

Guess its time to get a new code book and add my 2018 to the archives.

Yeah, I have a 2018 illustrated version. I'll use the free online version for newer editions at this point.

 

[Jeff H Young]

Guess its time to get a new code book and add my 2018 to the archives.

Ive got 85 , 91, and 2000 covered its kinda hard to look up on line some arent free anymore I suppose I could pay for online

 

[Tuttles Revenge]

My last illustrated is from '09.. cost $250! I think I might spring for it this time. IAPMO is listing it for $212 or so.

I have an '06, i09, 12, 15, 18. Pretty sure I had one from the 90's when I started taking code classes.

IAPMO makes all of their material free online. But its hard to read with the watermark in the middle. I find its easy for me to Search their online version for obscure stuff first then read it in my own book.

 

[Jeff H Young]

I have a prized book from 1938 reprinted in 47 called Audells plumbers and Steamfitters guide it was mail order and in the back has other guides welders guides, power plant engineers guide , you name it hard cover books starting at 1 dollar and as high as 4 dollars. yard sale couldnt pass on it