the smell of natural gas

[Mattk]

am i right in thinking that natural gas is actually odourless and its smell is added later ?

if so,how & when ? Also , who decided the smell would be the one we know and love ?!

Thanks .

[xrayspecs]

You are correct. The smell of gas is added to make it detectable, and also prevent people from using it to commit suicide. The idea was that the smell would make the suicide attemptee sick and thus abandon their attemt before any real harm was done.

Another interesting fact about gas (which a gas fitter told me) is that if you fill a room completely with gas, then strike a match - it won't explode! I've never tried it, but have no reason to disbelieve him!!

[lady_p_gold]

I was under the impression that you could commit suicide with the old gas but when it changed to natural gas you could not longer 'put your head in the oven' and commit suicide as it is not toxic like the old stuff. Perhaps someone could elaborate.

[xrayspecs]

It's not the gas that kills you, it's the fact that the air is replaced in your lungs with gas, which doesn't contain oxeygen and therefore you die!

[qapmoc]

The ''old'' gas contained large amounts of carbon monoxide, Carbon monoxide inhibits the blood's capacity to carry oxygen. In our lungs, CO quickly passes into our bloodstream and attaches itself to hemoglobin (oxygen carrying pigment in red blood cells). Hemoglobin readily accepts carbon monoxide - even over the life giving oxygen atoms (as much as 200 times as readily as oxygen) forming a toxic compound known as carboxyhemoglobin (COHb).

By replacing oxygen with carbon monoxide in our blood, our bodies poison themselves by cutting off the needed oxygen to our organs and cells, causing various amounts of damage - depending on exposure.

The ''new'' gas does not contain carbon monoxide and so is very safe.

And yes a space completely filled with gas will not explode it has to be mixed with oxygen at a specific ratio to be come explosive.

[xrayspecs]

I thought the old or "town" gas as it was known, was Methane. And isn't carbon monoxide a bi product of burning fosil fuels like gas...!? It's not present until it's liberated by burning.

[brachiopod]

"Town gas" was derived from coal, and was made at the local 'gas works' it contained a mixture of aliphatic and aromatic hydrocarbons and carbon monoxide.

Natural gas is mainly methane.

Carbon monoxide is also formed by incomplete combustion of a fuel. In a properly ventilated environment, this carbon monoxide (CO) is itself burnt (oxidised) and burns with a blue flame to form carbon dioxide (CO2), but if ventilation is poor, their is not enough oxygen to oxidise the CO to CO2 and so it builds up. This can cause carbon monoxide poisoning as described by qapmoc.

[Gef]

Brachi is correct exce[t that Town Gas was a mixture of hydrogen (not hydrocarbons) and carbon monoxide.

Dimethyl sulphide (also found in truffles!) is one of the compounds used to give the gas a smell - I think.

[BobbyBobBob]

Transco add the smell at local distribution points, they have a man with a tank of ethylene glycol based odour on his van that goes around topping up.

I understood that the smell was chosen to be similar to Town Gas but I'm too young. . .

[Jay70]

I didn't think you could gas yourself in an oven unless it was fairly old anyway as ovens have had thermo couples fiited for quite a while now. These prevent the gas comming out unless heat is present i.e if the oven is not lit.

[stevie_c2it]

It all depends on what you've been eating!

[Hamish]

Tertiaybutyl mercaptan, or 2,2 dimethylpropanethiol is used to give gas its smell. Many other sulphur containing compounds smell similar. Dimethyl sulphide, as suggested abouve, is very toxic and is not used. We used to use the above counpounds in the lab, a slight spillage would have people running about for hours looking for a gas leak. The other stuff about CO etc is already clarified by the look fo it.