OT/HELP: any experience with teensy natural-gas leaks?

[wallymann]

so we had a whole-house generator installed last year. functionally, it's been a godsend.

however, installation necessitated running of a single/continuous 75ft length of flexible corrugated stainless steel tubing from the gas-meter to the generator. and ever since installation we've had a faint smell of gas in the house that was not present before the generator came along.

edit: the CSST installation runs entirely inside the house (2/3 basement and 1/3 crawlspace), except for the connections to the gas-main and to the generator which use short sections of black pipe until inside the rim-joist.

we've had the gas company check everything out and they did not detect gas-levels that posed an explosion risk. the contractor has bubble-tested the unions and no leaks big enough to cause bubbling were detected

but the smell is there, it varies, but its there and at times nauseating. we have friends/guests come over, and invariably they smell it. the smell is worse when we leave the house buttoned up for a few days, like take a trip or something.

the contractor is like "we tested the unions they're fine -- no leakage" and are showing no inclination to do anything more.

with that backdrop, what should i do?

[oliver1850]

I would replace the connector. My guess is the the seal between the connector and the flexible tubing has a slight leak.

[Mikej]

I would replace the flexible line with black pipe. Was the entire 75 ft run of corrugated bubble tested? If it was bent too much it could leak.

[Hindmost]

I wouldn't be comfortable with this situation either. Under the circumstances I don't think the bubble test (soapy water right?) is sufficient. Did the contractor do a pressure leak down test when installed? Will he do leak down test now?

Also, what can be said about the integrity of the generator?

[hokoman]

I had a leak in a rental house in Brooklyn. I could smell it at times and I knew it was coming from the range. I had 2 different contractors out and tried to figure it out, both used the soapy water test and sprayed all over the place. One said they smelled it and couldn't find it, the other said he couldn't smell it either. My wife didn't believe me, until finally her friend came over and mentioned it.

I called Con Edison and they sent someone - their sniffer machine tracked it immediately. It was the smallest leak coming from the flexible hose from the gas line to range.

I would try and get someone with a sniffer or whatever they call it to test again.

[Jaybee]

I had a leak in a rental house in Brooklyn. I could smell it at times and I knew it was coming from the range. I had 2 different contractors out and tried to figure it out, both used the soapy water test and sprayed all over the place. One said they smelled it and couldn't find it, the other said he couldn't smell it either. My wife didn't believe me, until finally her friend came over and mentioned it.

I called Con Edison and they sent someone - their sniffer machine tracked it immediately. It was the smallest leak coming from the flexible hose from the gas line to range.

I would try and get someone with a sniffer or whatever they call it to test again.

The "sniffer" is probably a PID, or photoionization detector. Should be able to detect methane down to the single PPM range, and the utility field crews should carry them as a safety tool.

[FlashUNC]

Keep pushing. The whole reason for the odor is to flag when its leaking.

[Dave]

I had gas smell near my meter. I used the special product that bubbles to show a leak and found nothing leaking at any fitting. Finally called the gas company and they found it with a sniffer. A union just needed tightening.

If there's a valve you can shut off, I'd shut the generator off until the leak is found.

[rwsaunders]

I'd start with the couplings as others have mentioned and code requires a shutoff valve between the supply line and the generator. Is the pipe above ground or underground? I ask as CSST by code needs to be installed in watertight, non-metallic conduit if underground as directly burying CSST can cause damage when backfilling. Last question and nothing to do with a leak, did the contractor bond and ground the CSST for lightning strikes?

[charliedid]

Rent or buy a tester ($25-$125 ) and see if you can locate?

We did this when I was managing properties. We would find teeny tiny pin holes. I worked with a guy who loved to light them with a match to light his smoke. That guy...

Hope you find it but I'd press the contractor harder as well.

[AngryScientist]

firts off, if they were just using soapy water, that's not good enough for small leaks, a product called "snoop" is much more sensitive with bubble action to find small leaks because it doesnt run off as fast:

https://www.trutechtools.com/thumbnail.asp?file=assets/images/ms-snoop-8oz.jpg&maxx=350&maxy=0

you may pick up a bottle of that and test yourself to prove where the leak is or might be.

realistically though, you paid someone for an installation and now you smell gas. as flash mentioned, the whole reason they oderize gas for residential applications is for safety concerns to alert people of leaks; and if you and others smell gas - there is obviously a leak. i would push the issue until they fix you up - that's part of a complete job.

if they arent too responsive and you want to fiddle with it, i'd shut the gas off, take apart the union to the flex hose, clean the mating surfaces, grease the threads and re-tighten everything - that might just fix your issue without too much hassle.

[Mikej]

Rent or buy a tester ($25-$125 ) and see if you can locate?

We did this when I was managing properties. We would find teeny tiny pin holes. I worked with a guy who loved to light them with a match to light his smoke. That guy...

Hope you find it but I'd press the contractor harder as well.

Pretty sure the corrugated flexible line runs through the basement and is connected to the main hard plumbed black pipe to the generator, so it’s not the generator valve to be concerned about, that’s outside. Replace the line with black pipe, I was a pipe fitter at one time.

[charliedid]

Pretty sure the corrugated flexible line runs through the basement and is connected to the main hard plumbed black pipe to the generator, so it’s not the generator valve to be concerned about, that’s outside. Replace the line with black pipe, I was a pipe fitter at one time.

Good advice

[sparky33]

Don’t f around or call it good enough.
It’s not right if you can smell it.

[PeregrineA1]

I’d run poly pipe under ground and the flex only at the gen set to account for vibration. I would be surprised if the flex is certified for direct burial. Hard pipe the connection to the meter to poly underground to hard pipe riser to flex. More money, more work, most safe. Check the code.


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[oliver1850]

I would replace the flexible line with black pipe. Was the entire 75 ft run of corrugated bubble tested? If it was bent too much it could leak.

Guessing that part of the run is in a wet location where black pipe is not going to hold up. I replaced black pipe with flexible stainless on a run through a crawl space where rust had nearly penetrated the black pipe.

[Mikej]

Guessing that part of the run is in a wet location where black pipe is not going to hold up. I replaced black pipe with flexible stainless on a run through a crawl space where rust had nearly penetrated the black pipe.

Interesting I had figured this was in a basement. Still wouldn’t want to bury ss corrugated, but the poly mentioned earlier may be the answer IF it needs to be buried, but again it was mentioned you couldn’t bury ss corrugated.

[Black Dog]

firts off, if they were just using soapy water, that's not good enough for small leaks, a product called "snoop" is much more sensitive with bubble action to find small leaks because it doesnt run off as fast:

https://www.trutechtools.com/thumbnail.asp?file=assets/images/ms-snoop-8oz.jpg&maxx=350&maxy=0

you may pick up a bottle of that and test yourself to prove where the leak is or might be.

realistically though, you paid someone for an installation and now you smell gas. as flash mentioned, the whole reason they oderize gas for residential applications is for safety concerns to alert people of leaks; and if you and others smell gas - there is obviously a leak. i would push the issue until they fix you up - that's part of a complete job.

if they arent too responsive and you want to fiddle with it, i'd shut the gas off, take apart the union to the flex hose, clean the mating surfaces, grease the threads and re-tighten everything - that might just fix your issue without too much hassle.

Greasing threads is not what should be done with gas line connections. Joint compound with teflon is what should be used.

[Hellgate]

And I thought you were talking Mexican food...

[oliver1850]

Interesting I had figured this was in a basement. Still wouldn’t want to bury ss corrugated, but the poly mentioned earlier may be the answer IF it needs to be buried, but again it was mentioned you couldn’t bury ss corrugated.

My guess is that the source connection is in the basement but it runs through the foundation and underground to the generator.

For burial it's supposed to be inside watertight conduit. I don't know what other options there are for direct burial, but I'm guessing stainless pipe would be one. On our farms where LP is the gas used, it's common to use copper tubing for direct burial. Don't know if that is recommended for NG.

The most corroded place in the black pipe I removed was actually not in the crawl space, but about 6' inside the basement wall, on the bottom side of the floor joists.

[wallymann]

Pretty sure the corrugated flexible line runs through the basement and is connected to the main hard plumbed black pipe to the generator, so it’s not the generator valve to be concerned about, that’s outside. Replace the line with black pipe, I was a pipe fitter at one time.

correct. the CSST installation runs entirely inside the house (2/3 basement and 1/3 crawlspace), except for the connections to the gas-main and to the generator which use short sections of black pipe until inside the rim-joist.

i picked up a couple sniffers. a continuous monitoring deal i can leave in various locations to track over time, as well as a flex-neck deal i can point at connections and such to ID/target leaks very precisely.

[AngryScientist]

Greasing threads is not what should be done with gas line connections. Joint compound with teflon is what should be used.

BlackDog - I agree that pressure retaining threaded connections should use joint compound, but i was talking about the threaded connection on a union that is only used to force the machined mating surfaces of the union itself together. it's helpful to grease those threads to get easier engagement to force the mating surfaces together. Getting them together straight with clean mating surfaces is key, and enough pressure from the threaded connection to keep leaks down.

http://i.imgur.com/YHLMuL1.jpg

[Hawker]

Man...I've learned a lot from this thread. When did all you guys get so smart?

Good luck, OP. I suspect that perhaps "teensy gas leak" may be an oxymoron. ;)

[Dekonick]

I wouldn't be comfortable with this situation either. Under the circumstances I don't think the bubble test (soapy water right?) is sufficient. Did the contractor do a pressure leak down test when installed? Will he do leak down test now?

Also, what can be said about the integrity of the generator?

BINGO -Did they do a pressure leak down test? I'll bet not. IN ADDITION - I would not accept yellow CSST gas line in my home. It is a fire hazard implicated in many lightning strike fires. Lightning strikes, heats the CSST, creates a pin hole, auto ignites the gas, and you have a tiny gas fed flame... wherever that pinhole happens to be. In the crawl space, wall, wherever. They say it can be prevented by proper bonding... I am not convinced. Often the plumber says the electrician should do it... the electrician says it is the plumbers problem... or if it is a project addition later on... who knows? It may be code today, but if I were a betting man, I'll bet sooner or later the code will change. You can get the black CSST - that is a commercial grade. It isn't as good as iron pipe, but better than the yellow crap. JUST MY OPINION but do a little research and you will find out this is all true. All I know is I have seen quite a few homes burn to the ground where the yellow CSST has been implicated... Now - to find a tiny leak: Replace the fittings. If the problem persists, it is probably the CSST. Do check your other gas appliances too... :)

Best of luck.

[Dekonick]

My guess is that the source connection is in the basement but it runs through the foundation and underground to the generator.

For burial it's supposed to be inside watertight conduit. I don't know what other options there are for direct burial, but I'm guessing stainless pipe would be one. On our farms where LP is the gas used, it's common to use copper tubing for direct burial. Don't know if that is recommended for NG.

The most corroded place in the black pipe I removed was actually not in the crawl space, but about 6' inside the basement wall, on the bottom side of the floor joists.

Continuous copper can be buried, at least by code Ellicott City.

[Tandem Rider]

Continuous copper can be buried, at least by code Ellicott City.

Copper sometimes reacts with Natural Gas, pinholes and leaks down the road. I can't imagine direct burying uncoated copper for any fuel gas, I've seen too many leaks over the years on refrigerant and water lines.

Finding the leak usually isn't too hard, unhook and cap or plug the line at each appliance and the meter connection. Pressurize with air to 60 to 100 psi, listen for the leak, if you don't hear it, leak soap will find it. Fix the leak(s), double check every single joint, the re-connect each appliance and leak check the new connections with soap.

[Dekonick]

The "sniffer" is probably a PID, or photoionization detector. Should be able to detect methane down to the single PPM range, and the utility field crews should carry them as a safety tool.

Yes - There are meters, and there are meters... Nothing you buy is going to compare to anything the gas co field units carry. The PID units are expensive...

The black CSST is a far superior product to the yellow. https://www.mopropanesc.org/news-1/arc-resistant-csst

http://www.tracpipe.com/technical/csst-installation-instructions/

https://www.youtube.com/watch?v=OpGsZ4xxzj8

Video with plumber showing a cut off section of yellow CSST with a pinhole from an arc from a lightning strike https://www.youtube.com/watch?v=BOfioT9fq6Y

[Dekonick]

Copper sometimes reacts with Natural Gas, pinholes and leaks down the road. I can't imagine direct burying uncoated copper for any fuel gas, I've seen too many leaks over the years on refrigerant and water lines.

Finding the leak usually isn't too hard, unhook and cap or plug the line at each appliance and the meter connection. Pressurize with air to 60 to 100 psi, listen for the leak, if you don't hear it, leak soap will find it. Fix the leak(s), double check every single joint, the re-connect each appliance and leak check the new connections with soap.

Does anyone still have 'wet' gas? I digress - Personally, I wouldn't use copper but it was code last time I checked. I DEFINITELY would not use non-arc protected CSST. Valid point on copper - just like water lines, copper can corrode. Wet gas, contaminated with other hydrocarbons and sulfur and sometimes water vapor, can be quite harsh on plumbing.
https://www.eia.gov/energyexplained/index.php?page=natural_gas_home

[Black Dog]

BlackDog - I agree that pressure retaining threaded connections should use joint compound, but i was talking about the threaded connection on a union that is only used to force the machined mating surfaces of the union itself together. it's helpful to grease those threads to get easier engagement to force the mating surfaces together. Getting them together straight with clean mating surfaces is key, and enough pressure from the threaded connection to keep leaks down.

http://i.imgur.com/YHLMuL1.jpg

Ok. I agree. Grease in that application is fine. Some jurisdictions would still not allow it but not for any safety or functional reason just to reduce risk of using greas on pressured threads. Teflon joint compound would do the same job as grease. But I am not disagreeing with you.

[Dino Suegiù]

Copper sometimes reacts with Natural Gas, pinholes and leaks down the road. I can't imagine direct burying uncoated copper for any fuel gas, I've seen too many leaks over the years on refrigerant and water lines.

Yes. What is ironic is that while Natural Gas itself isn't really corrosive to copper pipe (which should be graded for NG and not just water or propane, btw) what usually causes the copper to corrode is the hydrogen sulfide/sulphur which is added to the NG as the warning odorant. So, the corrosion can occur regardless of the copper pipe's location.

There is even a prescribed HS limit per x SCF of copper pipe, so one needs to know the HS content of the locally supplied NG.
Here, but if using copper I would verify if that formula is still current:
"Copper and copper alloy tube (except tin-lined copper tube) should not be used if the gas contains more than an average of 0.3 grains of hydrogen sulfide per 100 standard cubic feet (scf) of gas (0.7 mg/100 L)."

As Mikej and others wrote, Schedule 40 black iron is just safer than copper. If exposed to heavy moisture/underground, then poly. Long runs of corrugated...just add up all the extra surface area prone to kinks and pinholes, so again also best avoided when possible. Copper and CSST flex are the worst options for NG.

Regardless, whatever the material, if I smelled gas in my house, especially to the extent the op has, I would definitely not risk it nor rely on soapy water, other half-means, not even "sniffers" I was operating myself as I'm not a plumber and NG isn't H2O:
I would have a qualified professional source out the issue and properly repair it (and probably avoid copper and/or CSST flex as much as possible, preferably entirely, as dekonick recommended above).