Find Gas Leak

mccm · Jan 8, 2010

When it gets extremely cold, like below zero, I get a faint gas smell in my garage. The gas pipes go across the garage on the way to the basement.

I've had the gas company out and they can't find it. I've got a gas sniffer that I've been using to no avail. All fittings and along pipe don't show a leak.

Even though I can smell the gas, the sniffer is not going off when I'm in the garage. I know it works as I've tested with the stove.

So it's a very low concentration but you can smell it.

Obviously would like to fix it...

Presure test maybe?

Any thoughts on how to find this?

Thanks

Msgale · Jan 8, 2010

maybe it's not natural gas from your pipes.
spilled gasoline, car leaking some fluids,other petroleum products, maybe

Sponsor · 2022-01-29T12:20:58-0800

Hackney plumbing · Jan 8, 2010

mccm said:
When it gets extremely cold, like below zero, I get a faint gas smell in my garage. The gas pipes go across the garage on the way to the basement.

I've had the gas company out and they can't find it. I've got a gas sniffer that I've been using to no avail. All fittings and along pipe don't show a leak.

Even though I can smell the gas, the sniffer is not going off when I'm in the garage. I know it works as I've tested with the stove.

So it's a very low concentration but you can smell it.

Obviously would like to fix it...

Presure test maybe?

Thanks

Your smelling the oderant they mix into the gas or somthing that smells like it. Mercaptan is used alot. Its also flammable and your detector should pick it up before your nose will. I'd have my instrument calibrated and recheck. I realize you said you tested it but your trying to find a very small leak and the detector may have lost some of its sensitivity. I would consider a high pressure gas test but would disconnect and cap all the appliances and blow it up to 100psi and get the soap out and start soaping.....you may could even hear it at that point. Chances are your not at all in any kinda danger but it could be a cracked fitting that only leaking with expansion and contraction....it might fail in the future and cause a bigger problem.

hj · Jan 9, 2010

test

Pump most gas systems to 100 psi, and you WILL have a leak, probably one you did not have before you did it however. Testers are much more sensitive than your nose, so if they do not find a leak there probably is none, unless it is so small that air currents are carrying it away before the detector can sense it. Odors are airborne, and will accumulate in dead "pockets", so they can show up in nooks and crannies a long way from the source of the smell.

mccm · Jan 9, 2010

I have thought that maybe it was something else besides the gas lines.

But it has been going on for a few years now and I can't figure it. It does seem to pocket up in a dead space as where it smells strongest there are no fittings whatsoever. It's near the door so I figure maybe the pressure difference due to heating causes it pool up there.

Regardless, while it is insignificant I'd like to find it. The sniffer is good as it detects gas near the stove even after it's been turned off for a while and the smell is gone.

I wonder if I shouldn't just put some type of external sealant on all the fittings to see if that fixes it. I've used some of that stuff on leaky pipes before and it worked. Or hire someone to just redo all of them. There's only three 90's along the run.

Or maybe global warming will take care of the problem

Hackney plumbing · Jan 9, 2010

mccm said:
I have thought that maybe it was something else besides the gas lines.

But it has been going on for a few years now and I can't figure it. It does seem to pocket up in a dead space as where it smells strongest there are no fittings whatsoever. It's near the door so I figure maybe the pressure difference due to heating causes it pool up there.

Regardless, while it is insignificant I'd like to find it. The sniffer is good as it detects gas near the stove even after it's been turned off for a while and the smell is gone.

I wonder if I shouldn't just put some type of external sealant on all the fittings to see if that fixes it. I've used some of that stuff on leaky pipes before and it worked. Or hire someone to just redo all of them. There's only three 90's along the run.

Or maybe global warming will take care of the problem

What kind of gas do you have natural or propane? Both are a type of natural gas but theres a difference. natural gas is lighter than air and will not pool up but propane will pool in low spots or pockets. before i replaced it i;d pump it up to a high pressure and repair the leaks. I pressure test all my new gas work to 100 psi for 2 hrs. I go above and beyond code.

mccm · Jan 9, 2010

It's natural gas. I think pressure test is a good idea for the next step.

ilya · Jan 10, 2010

Here in Akron Ohio the gas co. tests 4# for 3 minutes, or it's 3# for 4 min. Old test was 10 for 10; I use 5 for 5. I DID once blow the seal on one of the old valves packed w/ grease by testing @ 20#. Anybody know what type of grease can be used to repack those? Not the ones w/ rubber, these have a cone shaped "stem" forced tight w/ a screw, sometimes called a "B valve", for the pilot outlet.

Find Gas Leak

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