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BobbyJoeCool

Natural Gas

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Under what conditions is Natural Gas exposive... Say, a room, with exceptional ventalation (a system designed to keep smoke and soot out of the room from a flaming system).

 

The reason I ask: there was a gas leak at work, you could smell it (strongly) pretty much within 4 ft of the gas pipe, and nothing anywhere else. And, we have an open flame broiler. And there was a mild amount of panic involved... And I was trying to tell people that gas is only explosive in compressed pockets, and with the vents running, it wasn't getting anywhere...

 

So the question... as I right, or just a little intoxicated by the gas. Thanks.

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Natural gases contain alkane, such as methane, propane.

I've heard that they do not combust with oxygen if oxygen concentration is higher than a certain level.

Besides, they do not have smell.

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Natural gas itself doesn't have a smell, but manufacturers put in an additive to make it smell so leaks can be more easily detected.

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Generaly a 4-to-1 ratio of air to gas is the most explosive, however this is not carved in stone, The point is that any gas leak should be taken seriously. Check it out with a solution of liquid dish-soap and water and attend to it ASAP>

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Generaly a 4-to-1 ratio of air to gas is the most explosive, however this is not carved in stone, The point is that any gas leak should be taken seriously. Check it out with a solution of liquid dish-soap and water and attend to it ASAP>

 

I will echo that!

 

What may have saved the day is the fact that natural gas is lighter than air, so if there were ventilators in the ceiling and especially if those vents were close to the point where the leak occured, that may have kept the concentration down to a level where an explosion would not be likely to occure.

 

But, to repeat, when you smell a gas leak, get the Hell out of the area--in this case out of the building.

 

If anuone knows where the shutoff is, shut it off as fast as possible and call the gas co..

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there are special gas sniffer probes that can used, however I HAVE seen it done on smaller leaks with a cigarette lighter, I don`t advise this, as technicaly "Safe" as it is, the jet could still set fire to something else.

couldn`t you get a portable fan and put it by the area, and your nose and then ears to find it? my guess is that it`ll be around a pipe joint, as the pipes themselves rarely to never fail.

 

a proffesional would find it for you in minutes, AND it wouldn`t void your companies insurance :)

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Check it out how with dish soap and water? Check to see if (where) it's leaking?

 

Yes, done it myself. But I was thinking more of a home vs workplace situation. I've done gas-work; if your not comfortable with that yourself seek help from a pro.

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yea, well... I could find the leak (because I could feel it, and hear it). It wasn't a problem. I thought you meant find ratio in the air with the dishsoap, and I'm like huh?

 

but the whole point is, gas (and most things for that matter) don't explode unless they are compressed and REALLY "want" to expand, and fast.

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...but the whole point is, gas (and most things for that matter) don't explode unless they are compressed and REALLY "want" to expand, and fast.

 

Nat.gas WILL explode at STP if an ignition source is available. Keep in mind that the energy from such an event comes from rapid oxidation of the fuel, not compressive release

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true... I should have known that too... but still... with the vents above it running full boar, I doubt there was any real danger...

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This is a slightly related anecdote. I'm not sure how my brother heard this story.

 

A large natural gas main was broken and literally wailing gas. The fire department was all around pretty much just keeping people away and letting the gas company people do there thing. A guy from the company walks up with a lit cigarette and just tosses it into the gas pipe. It extinguishes. Meanwhile, the firemen were shitting their pants. He says, "ehh, it needs to oxidize first before it can burn."

 

True? Who knows. but it was amusing.

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... He says' date=' "ehh, it needs to oxidize first before it can burn."

 

True? Who knows. but it was amusing.[/quote']

 

I have seen similar stunts. What he ment to say is that it needs oxygen before it can burn and when an area is oversaturated with fuel there is no burn.

 

Nevertheless I suspect your story is a bit of an urbain legend.

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The gaseous alkanes and many of the liquid ones such as gasoline,kerosine and such readily combine with oxygen and under the right conditions explosively. It is very dangerous to expose such alkanes to an ignition source other than those systems such as a furnace, automoble engine, gas stove,etc., designed to utilize them safely. Always use caution when handling these highly flammable compounds. ...ds

Edited by dr.syntax
addition

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My hope is that the OP has figured out an answer to their question during the four years which have passed since they asked. After all, one can get a full college degree in that amount of time.

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Sadly, in 4 years, nobody even mentioned the important keywords here: Lower Explosion Limit and Higher/Upper Explosion Limit.

 

According to the link posted above, the lower explosion limit of methane is 4.4% by volume. Any concentration higher than that and it can explode.

 

Here's a list of explosion limits for a bunch of gases. Natural gas can be assumed to be mostly methane.

http://www.engineeringtoolbox.com/explosive-concentration-limits-d_423.html

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Sadly, in 4 years, nobody even mentioned the important keywords here: Lower Explosion Limit and Higher/Upper Explosion Limit.

 

According to the link posted above, the lower explosion limit of methane is 4.4% by volume. Any concentration higher than that and it can explode.

 

Here's a list of explosion limits for a bunch of gases. Natural gas can be assumed to be mostly methane.

http://www.engineeringtoolbox.com/explosive-concentration-limits-d_423.html

 

After 4 years research it would be better to realise that there's an upper bound to flammabillity too.

"Any concentration higher than that and it can explode"

OK, so lets see you make 100% methane explode.

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OK, so lets see you make 100% methane explode.

 

Give me a big enough laser, maybe I can get it to go nuclear for you.

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After 4 years research it would be better to realise that there's an upper bound to flammabillity too.

"Any concentration higher than that and it can explode"

OK, so lets see you make 100% methane explode.

 

D'oh. That was a pretty poor way to say what I wanted to say.

 

Let's try that again: According to the link posted above (4 posts back), the lower explosion limit of methane is 4.4% by volume. Any concentration higher than that (but lower than the higher explosion limit) and it can explode.

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