Methane nightmare

[howco]

Just got back from a first trip this year 600 mile trip with the A/S. Had a strange thing happen while in Eastern Washington State. Camped at a nice park for three days, hooked up, all is well. After the third day I dumped my blackwater tank followed by a good greywater rinse. All is well..
That afternoon we started to smell gas. Thought it was propane, so I shut it all down, no change. I then deduced it had to be methane. Checked everything out no leaks nothing. HINT: the rear bathroom has almost no smell, the bedroom area (midships) had a heavy smell. I looked and looked, finally I laid under the trailer on my back and did an inspection, no seepage, wetness nothing. Then I started to cough and could not stop, so I scrambled out and walked away to get some fresh air. By now it was night, so a friend offered to put me up at his house until we could find the problem. After spending the night, we ripped all bedding out looked at all grey and blackwater lines, checked tanks, looked at both roof vents, not plugged. The smell went away and we came home, no problem. A few days later, I think I figured it out.
We were at the bottom of a slight graded hill, at the lowest point, with about fifteen full service sites above us. I had installed our drain flexpipe and loosely capped the sewer drain pipe in the ground. I am thinking a surge of gas came out of the ground pipe and pooled around the underside and outside area of the trailer. This did NOT happen the first two days...(weird) From now on I will pick the high end only and be sure to cap the ground pipe unless I am dumping. I thought methane was a lighter than air gas and would float away with the wind, but it must be a heavy 'ground hugger' gas. Any comments?????

[ROBERTSUNRUS]

Hi I think you already said it; I always keep the sewer cap on unless I have my sewer hose connected. Leaving the cap off allows the sewer system to vent right there.

[Gringo]

Good thing you quit smoking, eh?

[mopariac]

We had a similar problem while set up at a park near Dallas. I dumped the black tank and helped flush everything with steady running water. I even took a shower that helped clear the flex hose of all debris. Almost immediately after closing the black tank valve, I started smelling methane. It was strongest in the mid-bedroom area and the kitchewn/livingroom. The bathroom smelled fine. I opened up the windows and door and turned a fan on and the AC to help clear it out. It took quite a while. After doing this for the third time, I finally fixed the problem:

Because there is no grey tank, I leave the flex hose connected so we can use the sinks and showers whenever we want to and it drains out to the sewer system. I use a ladder support to angle the hose from the trailer to the sewer fitting. Then I started thinking about the methane traveling up the flex hose without blockage and traveling into the grey lines to the sinks and the bathroom. When I open the black tank valve the methane fills the black tank as I keep the valve open to drain the tank. I am not sure why the odor is stronger in the livingroom area but my solution to the problem:...

drop the flex hose in one small section from the ladder support in order to have standing water in the flex hose to prevent free gas travel from the sewer line back to your trailer (just like under each sink and bath). I have not had any methane issues since I made this one simple change.

Tharon

[dwightdi]

Traps on your sink drain should block the methane. Vent stack on the black tank line should get rid of it there. If not you should check to see if your stack and cap are not plugged.

[eubank]

Odd that the smell was not in the bathroom.

But it reminds me of something that happened with ours. The rig was plugged in to electricity all winter along, just sitting there. Towards spring (vacation time), I ventured in and smelled sewer gas. Ugly smell. It was strongest mid-ships, weaker in the rear bath and in the front.

I looked and looked and looked, finally following every line as best I could visually. Visually didn't help that much, but my nose did. The battery on our 67 rig is located under one of the two twin beds, and it was the battery that was making the stink. It was boiling.

Long story short: The old converter (not an original, mind you) went stark-raving mad sometime during the winter, so I wound up replacing both battery and converter.

But it sure fooled me. I could have sworn that it was sewer gas.


Lynn

[CanoeStream]

Gray water stinks. We use our shower for storage more than showering. The trap dried out once and gray tank smells permeated the trailer. Yecch!

A bidirectional Fantastic Fan that has an intake setting can pull in vent stack fumes if they are close to each other.

[DaveFL]

Originally Posted by eubank

. The battery on our 67 rig is located under one of the two twin beds, and it was the battery that was making the stink. It was boiling.

Long story short: The old converter (not an original, mind you) went stark-raving mad sometime during the winter, so I wound up replacing both battery and converter.

But it sure fooled me. I could have sworn that it was sewer gas.


Lynn

My experience was really the same as your problem but instead of the house batteries boiling it was the rechargeable batteries in the electric bike under the awning. More like H2S sulfurry sewer gas.
Automatic charger decided to keep a constant high volt charge overnnight, while at home it always shut down to a trickle charge.

[Splitrock]

I'm thinking methane is odorless. Maybe someone above your site had a propane leak. Propane has ammonia odor added and it goes down hill.

[jjustice]

Thanks for these posts. I had never even thought of such a problem so I will be keeping a look out for such issues the next times we camp. jjustice

[Gringo]

Originally Posted by Splitrock

I'm thinking methane is odorless. Maybe someone above your site had a propane leak. Propane has ammonia odor added and it goes down hill.

I was thinking that, too. But then figuring the source, there was probably some sulfides and other organically produced gases in addition to the methane. Methane itself is odorless and colorless, and also is not toxic. Just flammable as hell (pun intended) when it's mixed just right with air. It's pretty safe when contained. What's still puzzling me is that methane is lighter than air. It wouldn't flow downhill, or accumulate in a hollow. I'm guessing the smell was maybe the worst of whatever it was.

Since methane is odorless, how would you even know it was present unless you lit some of it off? I say some of it, because you probably would no longer care if it was present if you lit all of it.

[Splitrock]

Maybe we should all start carrying parakeets in a cage like a miner. Smell something? "Bring me the parakeet honey!"

[wasagachris]

Originally Posted by Gringo

Since methane is odorless, how would you even know it was present unless you lit some of it off? I say some of it, because you probably would no longer care if it was present if you lit all of it.

Methane is a combustible fuel just like propane so if you had a large enough quantity of it in your trailer the detector would go off.
BTW did you know that the propellant in aeresol cans is propane. When ever I had to test the functionality of a propane detector while prepping a new unit for delivery I used a can of air freshener to set off the detector.
My gas sniffer would also react to certain bodily functions also.

[Wsmith]

FYI - The smell in natural gas and propane is a very concentrated additive so you can tell it is present.
I have a feeling that the odor was plain and old decomposing poop (bacteria)

[overlander64]

Another thought of a possible cause for an objectionable odor could be the water heater, particularly if you are staying in a campground with well water. Certain well waters can impart a sulphur-dioxide odor when heated in an RV water heater. I know that certain RV water heaters have a sacrificial metal rod that can lessesn the odor.

Kevin

[Splitrock]

One year our son bought us a multi gas detector for use in our home. We proudly installed it near the bedroom door. My wife's hair spray set it off every time.

[howco]

Thank you for the help....well I learned Methane is lighter than air, and it has no smell. Sooo, what was I breathing? It must have been so concentrated it was in a layer, that had not yet lifted. The smell must be sulpher from poop. From now on, I will dump the Blackwater and cap it......
Thank you everyone.....

[Gringo]

ya just gotta stop the missus from chewin' on them kitchen matches...

[Smokin Camel]

Sounds like it may be Hydrogen Sulfide gas. It will form in sewers and areas with anaerobic digestion. Humans are more sensitive to it than dogs are...with good reason. Many rotting foods give of sulfide gas. The gas is slightly heavier than air.

The coughing and and so forth really make it sound like sulfide. The gas H2S will combine with water (eyes, mouth, throat--LUNGS!) and form sulfuric acid. That would account for the irritation feeling. A good dose will also provide one with a pounding headache.

This gas is often associated with methane from the anaerobic digestion processes and is also explosive. A concentrated version is know as silo gas, it can be very damaging and has been known to be fatal on rare occasions.

The post about the reversible vent fan is one to take note of. I have heard of that happening more than once. Leave the valve on your tank closed until the tank is high then flush the tank and close the valve.

[Gene]

Originally Posted by Splitrock

One year our son bought us a multi gas detector for use in our home. We proudly installed it near the bedroom door. My wife's hair spray set it off every time.

She said it was hair spray.

Methane ("natural gas") and propane are both odorless and have mercaptan added to give them what is usually described as a rotten egg smell. It smells like mercaptan to me, not rotten eggs.

Propane is heavier than air, methane is lighter than air.

Sewer gas comes from the breakdown of the wonderful stuff in the fluid—and produces many odors including hydrogen sulphide (H2S, a compound each of us can produce on our own). All college male freshman learn it is flammable, an experiment conducted in the dorm, not a lab. The compound breaks down fairly quickly in air.

Battery acid is sulphuric acid (H2SO4) and the gas may break down into hydrogen sulphide when in contact with air, but I don't know that for a fact. I believe when a battery is overheated, it gives off hydrogen which is explosive in the proper concentration. Perhaps some of the hydrogen binds with some of the sulphur to make H2S.

Then there is the BTEX group—butane, toluene, ethane, xylene. These are really nasty and quite poisonous. Methane is not poisonous and is sometimes found in drinking water. When gas companies drill for natural gas, sometimes people suddenly get a lot of methane in their well water and can light the water when they open the faucet. They may also get fracking fluids which are also nasty as well as the BTEX group.

This all comes from someone who had an awful time with basic chemistry and was so bad at it he didn't know what he didn't know or thought he knew things he didn't know.

At some campgrounds there is a powerful odor of sewer gas when I open the drain, at others, not so. I suspect it is a function of how well the system was installed and how well it is maintained. Some don't have threaded drains and we use rocks, boards and anything else we can come up with to create a positive seal—sometimes it works, sometimes it doesn't. Someone nearby may have a broken drain and sewer gas may be blowing your way.

Gene