Venting Indoors

[winesalot]

Hey folks. First post here and it's not a pleasant one.

The wife and I are building a 10,000 sqft steel building that will house a production winery, a tasting room, and a small 3 bedroom residence. We have the building weathered in so we moved our 34 ft Alpenlite 5th wheel in to the space where the residence will be built while we finish the business portion of the structure. I hooked the RV's sewer hose up to one of the toilet drains in the building and we are dumping black and gray water in to our building's septic system that way. All is well except we are struggling with the trailer's black water tank vent stinking up the buildings air space. Especially when the wind is blowing outside. I would love to hear some ideas on how to stop this as, in my wife's word, we are tired of living in what smells like a porta-potty. Any great ideas?

[Matt_Colie]

OK Wines....

There are two very related issues here. The vents in a sewer system of an RV are for two purposes.
The vents on the gray water runs are to keep the flow from pulling the traps dry. Those you could cover with an air admittance valve. But the vent on the black tank has to accommodate the outgasing of the biological activity. This is the one you need to get outside.

That black vent does not need to be huge. It can actually be choked to something small and still function. Boats do this all the time because few can afford the 1-1/2 vent through a weather deck.

Now, can you see thought some of the edge of ribs in the steel roof? Get the largest piece of plastic pipe that you can push though there. There may be places between the panel joints that are not nailed, go to one of those. Join that up to you vent header. If you still get anything back, go outside and put a Ell up and another foot of pipe so the draft over the roof takes the outgas away.

Matt

[beemerphile1]

Leaving the gray open makes a path for sewer fumes to come from the drain and up into the vents. This can be prevented by creating a trap in the drain hose.

[mobeewan]

Air admittance valves on top of the tank vent pipes are a very bad idea. The tanks have to vent as they are being filled. The air admittance valve will allow air into the tanks when dumping, but will restrict liquid from entering the tanks with the dump valves closed.

Your drains will gurgle and flow very slow if at all when the dump valves are closed. If you try filling the grey tanks with the dump valves closed or do any back flushes on them, you very well may rupture a tank or cause a joint to leak especially at the tank connections. You might also cause the rubber flappers to dislodge inside the AAVs on the tank vents or even the ones under the trailer sinks rendering them useless.

With the dump valve closed on the black tank you will get you will get a displacement of tank air into the bathroom every time you flush the toilet. You might also get splashed with tank contents as the tank "burps" into the bathroom.

Vent through the roof, the end gable of the building or go through the wall into the other side of the building and tie into a plumping vent there.

[dedmiston]

Before you install that, I would experiment with closing the gray valves too just for kicks and science.

[winesalot]

Thanks so much for all the great answers and, of course, a few silly ones.

I have been keeping the two grey water tank drains open, and want to continue doing so, which is the source of the back air flow when the wind blows. I do keep the black water tank valve shut and we celebrate Sundays by draining and flushing that tank. It's like a party!!! Yippee!!! But at least there is no poo pyramid as so eloquently stated above.

I had ordered all of the parts to do a makeshift connection to all three vents and vent the assembly through the building roof. I have to admit I was not excited about the prospect of punching a hole through my new steel roofing without knowing exactly where the plumber would do so later on in the project.

The big prize of the day goes to Lantley for the suggestion of the Air Admittance Valve. This is the best idea ever. I did not know such a thing existed. I just ordered three of them and I'll report back on how they work once they are installed.

Cheers everyone.

[time2roll]

Move the trailer outside? Park next to the sewer clean out to dump.

[Lantley]

I believe a Studor vent would resolve the issue without having to run a pipe through the roof. Just install the Studor vent on the RV roof vent.

Studor Vent-
Air Admittance Valve

[wa8yxm]

The automotive world has an answer.. a Flexible exhaust hose. remove the "hat" from the stink pipes and use exhaust extention to take 'em up through the roof.

Seal to the roof as you would a toilet vent line but cap it with a "hat" like the one on the RV so rain does not enter it. I would also screen the top for insect control.

When done leave them as roof vents.

[Jebby14]

if you're valves are open your going to have a poo pyramid to deal with too

[Gdetrailer]

If you are keeping the RV connected via drain hose, be sure to CLOSE both grey and black tank valves!

Otherwise when it gets windy outside the septic/sewer stack vent pipe can create enough reverse air flow (downdraft) to push the septic/sewer gas back into the onboard tanks and out the tank roof vents into your interior space.

I would also second the idea of connecting your roof vents on your RV to a roof vent for your building to the outside.

However, I would not recommend using all rigid pipe, you WILL want some FLEXIBLE pipe to connect to your RV roof vents. This allows for any movements of the RV suspension or any slight movement of the wheels without putting unneeded stress on the RV plumbing.

You also do not want the extra pipe weight to rest on the RV plumbing, that extra weight could possibly break or damage the on board tanks or push the vent pipes down into the tank which would be bad..

[mike_brez]

x2 on all other drains being capped and traps filled with water.
extend rv vent to outside. I would just use some cheap light weight dryer vent hose.

[pinesman]

Are you sure that it is the RV vent and not another building drain pipe which is open and allowing fumes to come back into the building?

[Lynnmor]

Use the black tank flush often, add one if needed. keep the tank valves closed except for the brief time when dumping. Use plenty of odor preventing chemicals. Other than that, extend the vent outside as stated above.

[corvettekent]

I would use a 1.5" PVC pipe from the RV black tank vent to outside the building. Yes you will need to drill a hole in the building wall or roof.