Natural gas smell.

The essence of this little tale is that the normal odor of natural gas may be a lot different if the concentrations are low enough.

A couple weeks ago I noticed a smell of "carmalized onions" in my kitchen. It came and went and I poked my nose into drawers, cabinets, garbage cans as well as behind stove and refregerator.
Nothing.

This morning I heard a hiss which stopped when I touched the gas line behind my stove. Soapy water did not reveal any leaks.

I went to move the pipe again and got a shock where an extension cord crossed the pipe... It turns out that there was a pinhole leak at this point which was being blocked frequently by the movement of the cord. BUT the cord was being damaged enough so that sooner or later it - hopefully would have blown a fuse before causing a spark.

Even after finding and feeling the leak it was not enough to give the normal smell but rather a not unpleasant smell similar to sauted onions where it concentrated in the middle of the room.

I called PG&E and they acknowlegded this different smell is not uncommon.

Now I'm going to get a match and see if there are any leaks in my repair.
Talk to you later????

Methinks a match is not a good idea. Stick with the soap bubbles!

Oh, the *stove*.

I was about to suggest Beano.

Yea, I can't remember that nasty chemical that they put in 'gas' to make it smell so bad, but I know what you're talking about regarding a different smell when the concentrations are low. Thank heavens you found it. :sweat:

PhotonWrangler said:

Methinks a match is not a good idea. Stick with the soap bubbles!

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Now he tells me. I knew a woman once who when PG&E told her "A day or two" she would tell then that she would get a match and try to find the trouble herself.
Worked every time, they sent somebody right out.

:candle: = = :mecry:

Sleestak said:

Oh, the *stove*.

I was about to suggest Beano.

Yea, I can't remember that nasty chemical that they put in 'gas' to make it smell so bad, but I know what you're talking about regarding a different smell when the concentrations are low. Thank heavens you found it. :sweat:

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Do a search for mercaptan. Its a commonly occurring organic compound. Its one of the molecules that human noses are the most sensitive to.

sulfur dioxide ?

nope


methyl mercaptan = bad smell

Yep, it's Mercaptin.

If there's a shutoff valve on the gas pipe going to the stove, turn that off and see if the leak stops. Don't have a valve there or the leak is before the valve? Shut it off at the meter.

Blow some fresh air towards that area and wait for the gas to clear out.

If you want to do the match trick, (I knew a plumber who did the same thing hooking up my neighbor's water heater but he did it with a propane torch )
The match trick:
Light a match (when all the gas has cleared away of course), turn the valve on slowly, and wave the lit match near the connections and along the length of the flex connector. You'll get a flame once you find the leak. Be ready to shut the valve back of and blow out the fire.

In the case of the plumber, he just tightened the connection until the flame went out and double-checked to make sure there were absolutely no leaks at all. If that dosen't work or you find a pinhole leak in your flexable line, replace the entire line and connector.

Yea, mercaptan, that's it!

IIRC, I read somewhere one time where a tanker truck loaded with the stuff, or a tank holding it somewhere broke open, and the smell was so horrid that they had to evacuate folks left and right, and the hospital filled up with folks who were sick to their stomachs as a result.

Nasty stuff, and I wish I'd of had a bottle to throw at the neighbors last weekend when they had vulgar Karaoke going on up to 3 am.

You turned this off going to your stove, did you?

yuandrew said:

If you want to do the match trick, (I knew a plumber who did the same thing hooking up my neighbor's water heater but he did it with a propane torch )

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I'm a lot more comforatable with soap bubbles.
The plumber would have used a toarch because a good leak might just blow out the candles.

The problem with the torch method is that if he checked for leaks far enough downstream from the valve he might have encountered an explosive mixture of gas.

We did a standby for a ruptured main into a house and the PG&E repairman wacked and pried things with metal impliments. He paid no attention to the gas until he had a clamp on it and had started to tighten it down.

Then he grounded himself and the tools to the pipe and finished the job.

Methyl mercaptan has one of the most easily detected and recognized odors of all chemical compounds. Extermely small amounts can be smelled and that's why it's added to natural gas.

It only takes one little spark to make the proper concentration of gas go kaboom. Best thing to do in a gas leak situation is to get out of the house and go next door to contact the gas company or the fire department. If there is a strong smell of gas in the house, don't switch anything on or off, don't use the phone, dont do anything but get out. Use the phone next door.

Why be so careful? There have been several gas explosions in this area over the past decade or two. A few completely leveled the houses -- nothing but sticks left after the blast.

Sleestak said:

Yea, mercaptan, that's it! Nasty stuff, and I wish I'd of had a bottle to throw at the neighbors last weekend when they had vulgar Karaoke going on up to 3 am.

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Fox lure http://www.bugspray.com/catalog/traps/page80.html

I heard it smells similar to skunk spray. Small amount goes a long way. You may want to hold your nose when you open the bottle.

Now if I could just get some paintballs and a syringe :naughty:

The smell of mercaptin is so strong that you can detect it with very low concentrations of natural gas. The idea is you could smell it before enough builds up to cause asphixation or ignite and explode.

I wonder what would happen if instead of using mercaptin, they used strawberry flavor or sperimint instead. (I heard this on a Gas Company commercial a long time ago)

When I ever smell that gas smell, its because one of the stove top burners are slighly moved from the of position, but not enough that it will light. Amazing how easy it is to hit one without knowing it.

I use to always smell it when I used the stove too. One day it blew up, threw the door open and opened my closed bedroom door. Turns out only one half of the burner was lighting.

I believe they use a sensor to find leaks and an open flame type detector for freon.

One of the good things about natural gas (mostly methane) is that its flammability range is narrow--about 5-15% by volume in air. Compare that to some other gases, such as hydrogen and acetylene.

Not something to be trifled with!

I work on pressure washers. Some are Gas heated. Way back in the 80's I was having a problem with one. I don't remember exactly why but it wasn't lighting well. Well at one point there was a and I lost my eyebrows!

I treat it VERY carefully these days!