Vent on RV Shower

[comet28024]

Good morning,

I have a situation where our camper had a significant water leak in the bathroom of our RV and I've since pulled out the tub and plan on replacing it with a shower. When I pulled the tub out I realized there was a hidden AAV beneath the tub rim for the vent.

The current plumbing is 1 1/2" ABS and I'd like to keep the drains as low as possible to maximize height.

My questions are 2 fold:

1.) Will the under sink AAV work even though it's roughly 80" from the shower p trap?
2.) Can I run the vent over to the wall where the handles are and turn it up into that wall and use an AAV there?
3.) Any other options, opinions?

I realize that both of these are not code compliant solutions, but this shower will get used 5-10 times a year and I can easily access the AAV in the wall if need be. I'm just trying to give the wife an acceptable shower while maximizing our space. From what I can tell, a lot of the reasoning for not allowing the horizontal vent is due to potential buildup, which in this instance I'm not concerned about.

Thanks,
Erick

 

[Breplum]

Basics:
1. Shower drains must be 2". Depending on shower head flow, you might get away with 1.5" drain, though rare to find 1.5" shower drain fitting.
2. AAVs must be permanently accessible and be min. 6" above the p-trap

 

[Sponsor]

 

[comet28024]

RV Showers drains are a standard 1 1/2, likely because of the inherent water saving showerheads, fixtures, etc.
I can easily get the AAV up 6" above the trap without any issue, but everywhere I've looked says the vent tee must turn vertical immediately. In this case I don't have any vertical room and would like to run it parallel to the shower line all the way to the wall. It would still slope towards the tank, just not turn vertical until it reaches the wall.

 

[Reach4]

I am not sure you need to add a vent. You seem to have a vented lavatory. That could serve as a wet vent.

Your diagram is lacking. For one thing, you don't show the path of the lavatory drainage.

I am pretty sure that RVs don't have to meet the same codes as houses, but the house techniques can be a good guide.

 

[comet28024]

Hopefully these images can help.

What you are looking at is the existing plumbing from the tub that was removed. The AAV closest to the p trap was underneath the lip of the tub (which wouldn't have been accessible).

There is a second AAV located underneath the sink where the shower drain ties into. Everything goes to the tank about 14" to the left of where the sink drain goes down.

As far as codes, I'm not bothered, but I would like a general, "yeah that should work". My concern is that if the vent under the sink was sufficient, why would they have added the one for the tub? I'm also not that concerned with the P Trap siphoning, as we keep the drains sealed when not in use. I mainly don't want to be standing in a puddle of water because it wont drain.

Edited for formatting.

 

[Reach4]

Does the drainage go under the floor at the bottom left of IMG_2586.50.jpeg? If so, and if the path from the shower trap to there is short enough, you would not need an additional vent.

Under IPC, the max length with 2 inch pipe would be 8 ft, and 6 ft with 1.5 inch pipe.

IPC wants 2 inch pipe on a shower, but for many years, 1.5 inch pipe was enough.

If the run is too long, you could put an AAV atop that vertical pipe in IMG_2484.50.jpeg That AAV should be accessible and vented to the air.

 

[comet28024]

So the drainage actually goes under the floor outside of the bathroom about 20" off of that vertical pipe for the sink. There is already an AAV on that vertical pipe next to the sink though.

The total distance of the trap arm to where that pipe vertical pipe goes up is roughly 64" so I should be under that 6ft requirement for 1.5" pipe.

From what I've gathered I can just eliminate the AAV that was by the tub and allow the shower to vent via the AAV under the sink and I should be good.

I appreciate the assistance, as it's such a gigantic pain to take this stuff out I'd hate to put it back together and have any issues.