Testing air

There are air testers certified by the US bureau of mines, not sure of what all they test for or if one machine tests everything. I know of them only because we had to use one before performing maintenance on the inside of aircraft fuel cells.
I assume a mine supply store would know what you would need.

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Originally Posted by hunabku

Dry cavers often carry a bic lighter as a simple check to see if there is enough oxygen to sustain the flame.

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It actually requires less oxygen to maintain a flame than what it requires to keep a person conscious. The exact percentage of oxygen required to sustain a flame is actually dependent on several factors. This number is somewhere in the neighborhood of 16% for your typical "Class A" combustibles (a BIC lighter runs off "Class B" combustibles). A flame can actually be sustained in even lower percentages of O2 in certain cases, most notably in the presence of other oxidizers or in cases where the fuel being burned contains some type of oxygenated compound (like ethanol). A bic lighter would be useful only for it's specificity and not it's sensitivity. In other words, if the flame won't burn, it is not safe to breath. If the flame will burn, it might have enough O2 to sustain life, or it might not.

http://www.ierents.com/ProductInfo.a...id=MSA10107602

Attachment 6481

This is the meter of choice for my fire dept. Very compact, should fit a small pressure case, but a bit pricy. $900+ range.

Measures Combustable/explosive gasses (hydrocarbons), Oxygen, CO and Hydrogen Sulfides.

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Originally Posted by floridakid

It actually requires less oxygen to maintain a flame than what it requires to keep a person conscious. The exact percentage of oxygen required to sustain a flame is actually dependent on several factors. This number is somewhere in the neighborhood of 16% for your typical "Class A" combustibles (a BIC lighter runs off "Class B" combustibles). A flame can actually be sustained in even lower percentages of O2 in certain cases, most notably in the presence of other oxidizers or in cases where the fuel being burned contains some type of oxygenated compound (like ethanol). A bic lighter would be useful only for it's specificity and not it's sensitivity. In other words, if the flame won't burn, it is not safe to breath. If the flame will burn, it might have enough O2 to sustain life, or it might not.

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16% is enough to sustain life, although you'll feel out of breath and tire easily. The problem with using a lighter is more practical since the flint is likely to get wet.

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Originally Posted by hunabku

Dry cavers often carry a bic lighter as a simple check to see if there is enough
oxygen to sustain the flame.

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Quote:

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Originally Posted by floridakid

It actually requires less oxygen to maintain a flame than what it requires to keep a person conscious. The exact percentage of oxygen required to sustain a flame is actually dependent on several factors. This number is somewhere in the neighborhood of 16% for your typical "Class A" combustibles (a BIC lighter runs off "Class B" combustibles). A flame can actually be sustained in even lower percentages of O2 in certain cases, most notably in the presence of other oxidizers or in cases where the fuel being burned contains some type of oxygenated compound (like ethanol). A bic lighter would be useful only for it's specificity and not it's sensitivity. In other words, if the flame won't burn, it is not safe to breath. If the flame will burn, it might have enough O2 to sustain life, or it might not.

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Sounds like we are in perfect agreement.

Some interesting reading on the subject...

http://wasg.iinet.net.au/Co2paper.html

Thanks for the link.

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Originally Posted by hunabku

Some interesting reading on the subject...

http://wasg.iinet.net.au/Co2paper.html

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The nature of the flame changes. If there is high CO2 it will be more yellow, taller and more separated from the lighter. But at that point you should be able to feel it anyway.

I've been in a number of caves with bad air, the symptoms of high CO2 are easy to recognize although how quickly it comes on and how bad it is varies mainly with the CO2 and your exertion level.

Panting while not moving and headache are two good ones. I wouldn't sweat it too much, just test it tentatively then pay attention to how you're reacting over time. Sometimes it takes a little while before you really notice it, but if you keep your exertion down you can really reduce the effects. If you get side effects very fast like immediately breathing hard, dizzy etc... then abort.

I will send Dave..lol I guess what we will do is hang out at the sump surface for a while with our regs in hand and if it seems cool then go out and over. Does depth underground have anything to do with how bad the air could be IE deeper worse etc..

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Originally Posted by phillip1

I will send Dave..lol I guess what we will do is hang out at the sump surface for a while with our regs in hand and if it seems cool then go out and over. Does depth underground have anything to do with how bad the air could be IE deeper worse etc..

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If your depth gauge shows anything deeper than zero feet in an air space, it means there is no connection to the surface, and could very easily have bad air. However, a partial connection to the surface could still hold bad air. Depth below the surface doesn't tell you much. In MX, there are sumps over a kilometer below the surface, and people spend days beyond those sumps with no problems with bad air.