Natural Gas Detection: How sensitive? How alarming?
January 4, 2019 9:23 AM   Subscribe

Short version: I'm thinking of getting a natural gas detector. If I put it in the utility room with the boiler and water heater, will I get a lot of false alarms? Long version below the fold

The SemiSalt household has had some issues with the gas-fired boiler, some of which left the smell of gas in the utility room. This has been at least mostly fixed, but my wife, sensitive soul that she is, says she sometimes still gets a whiff. The plumber may yet fix that. We hope so.

Still, a natural gas detector (we have plenty of CO detectors in the house) might help my wife rest easier, but I'm worried that if I put it in the utility room, it will give a lot of false alarms making the anxiety problem worse rather than better.

So, if any of ye MeFites have lived with a gas detector, did it seem over-sensitive, raising the alarm unnecessarily, or did it hold it's peace until and unless a dangerous condition was detected?
posted by SemiSalt to Home & Garden (6 answers total)
We have a similar situation where we'd occasionally smell a trace of natural gas near our gas meter in the basement. A man came out from the gas company at least two times and informed us that this is a common problem in older houses. Our cheap portable gas detector (and his official one) would go off just by being near his bare hands. Maybe a gas detector meant for permanent installation would be less sensitive than these portable detectors.

We wound up putting better ventilation in the utility closet that houses our gas meter in order to ensure that the gas concentration never rises to a dangerous level. This being accomplished, the gas company guy did not view our situation as a real problem, and I don't recall smelling gas since then.
posted by exogenous at 9:59 AM on January 4, 2019 [2 favorites]

I have smelled Natural gas odorant several times, just walking by the regulator/meter setup on the outside of different houses. The first time I told the owner of the house, and they had the gas company out to check and didn't find anything; I smelled it a couple more times after that and they never did find a leak.

I also noticed it more recently from a friend's new construction house. they also never found a leak. Either I am very sensitive to the odorant, or it is able to leak easier than the natural gas.

there's also this old thread with some suggestions on other things to check.
posted by ArgentCorvid at 1:15 PM on January 4, 2019

I'm pretty sensitive to the mercaptan oderant also. I was overseeing a rebuilding project at an apartment complex. The gas lines for the second floor just ran up the outside wall.
I kept smelling gas near the meters. Turns out the regulator - disc looking thing near the meter, has a relief valve. Its job is to lower the pressure of the gas from the mains before it enters the house to something like 2 PSI above atmospheric. If the gas expands in the line to the house, like if it is in a pipe sitting in sunshine, the regulator will "burp" to lower the pressure back to safe levels.
posted by rudd135 at 4:29 PM on January 4, 2019 [1 favorite]

That is not a leak, you are smelling gas from the regulator vent. It's normal. Don't worry, the vent is there for a reason.
posted by vonliebig at 3:41 AM on January 5, 2019

Dropping in to emphasize that my question is about detectors, not leaks.
posted by SemiSalt at 5:19 AM on January 5, 2019

I want to say that if the detector is reacting to the presence of methane in any amount, it's a true alarm, not a false alarm. Gas companies are notoriously lax about fixing leaks, unless they are fairly massive.

Before installing a detector, I would check every gas line plumbing joint with a rich solution of dishwashing liquid in water. Put the stuff in a squeeze bottle and squirt it on the joints. If bubbles appear and grow, there's a leak. Get the plumber to fix it.
posted by Kirth Gerson at 11:09 AM on January 5, 2019

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