Printable View
I know I posted this question somewhere else but I cannot remember were, anyway. If you were to dive a cave and after a while pop up into a dry cave how would you test the air to know if it is good.
My current solution is to have one guy breath the air while another is close at hand to shove the reg back etc.. but what about if you are solo? and at what point is it deemed safe air to breath and be able to get out of the water and check out the dry cave?
thanks
The only "safe air" in a cave is what you brought with you.
If for whatever reason it's a life or death thing, then testing is irrelevant. In the military I was taught if there was no other way to test for a chemical environment, you took the protective gear away from the least important person and watched< but what's your option assuming you have to have the air to survive anyway?
Phillip, its easy.
Before the dive, put a cat into a waterproof container, such as a pressure cooker or something. Take the cat with you until you reach the air chamber (hopefully its not too far or the cat will expire or you will have to install a O2 injection system and scrubber in the pressure cooker.). Let the cat loose in the air chamber and have it wander around for a while. You may have to tie a reel to the cat to make sure it does not wander off too far. If the cat falls over, then don't breathe the air.
Quote:
Originally Posted by OFG-1
A canary would be easier to transport and deal with....
But you don't want to risk the life of a canary - they serve other useful purposes in society.
Good luck getting a cat in the pressure cooker without a struggle. They are too smart to put up with that crap.
I'd recommend a small dog, or a puppy.
Dry cavers often carry a bic lighter as a simple check to see if there is enough oxygen to sustain the flame.
Sounds like a good question for a sump diver, or to post on NSS cave chat.
There are also small paper test strips for CO that are used on board light aircraft. In addition to testing for O2 content, you also should make sure the cave is not saturated with CO.
I like the Bic lighter idea, makes finding methane interesting, but hey your wet, what could happen?
but then you eat the catQuote:
Originally Posted by OFG-1
but not as tasty.Quote:
Originally Posted by Tegg
H2S maybeQuote:
Originally Posted by gschaut
Where would the combustion to create CO have come from?
Actually, one of the biggest dangers is high CO2. There have been cases in England, and Australia of high CO2 levels in air filled chambers that didn't have direct connection to the surface.
This thread reminds me of IFR flight with a cat and a duck
It is every bit as reliable :-DQuote:
Originally Posted by a64pilot
what about a mouse a cat is a bit big, or a kittenQuote:
Originally Posted by OFG-1
use an open water diver
First to fall over when the atmosphere is less than perfect.
Your sensibilities are shaken by the slightest defect.
You live your life like a canary in coal mine.
I say any small bird will do.
So this is the situation we will dive about 7000ft and come up in a very large dry cave, we then need to climb up a big breakdown pile and down the other side to get back in the water and continue exploring, Forrest being an experienced sump diver what would you do?
Don't worry Phil, I will be the Guinea pig. We can take a lighter.
I have yet to find a chamber after a sump that had air so bad it would kill without warning. I hold the reg close to my mouth and sniff the air. If it doesn't smell , or taste right, I go back on the reg. High CO2 will cause you to feel anxious, and tire easily. Low O2 in more subtle, if you feel faint, get back on the reg fast. You don't have long if the oxygen is too low.Quote:
Originally Posted by phillip1
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.
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.Quote:
Originally Posted by hunabku
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.
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.Quote:
Originally Posted by floridakid
Quote:
Originally Posted by hunabku
Sounds like we are in perfect agreement.Quote:
Originally Posted by floridakid
Some interesting reading on the subject...
http://wasg.iinet.net.au/Co2paper.html
Thanks for the link.
Quote:
Originally Posted by hunabku
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..
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.Quote:
Originally Posted by phillip1
As soon as you add dry caves in the mix it changes the game completely, it goes from easy cave diving to a much more complicated situation, turning a leasurly cave diving exploration into a richer underground experience.
Couple of random thoughts...
I got to 8% CO2 once during a medical experiment without changing my breathing frequency or depth, so not everyone feels anxiety with higher than normal CO2, (I was labelled a "non-responder"). For those interested in the details I started with 95% O2 and 5% CO2 and breathed a closed loop till we hit 8% CO2. I was quite relaxed throughout, although this was in a lab and I wasn't exerting.
Anyway, my second gem is that Tommy Graham's cave in the Nullarbor has a high CO2 level. It is also not that easy to get to. On my first and second visits, (each one 600+ miles drive), I looked around. On my third visit I tried walking around but tired soon, on my fourth trip I filled a couple of empty and washed Pepsi-bottles with water at the entry lake. When we surfaced in the chamber I unscrewed a cap, emptied the water and collected a sample of chamber gas. I did this again at the top of the rockpile you need to climb over to reach the second sump. My question was "If we need to leave someone here after diving the second sump and go for more gas, is it worth staying up the top or doesn't it make any difference?"
Then I asked for help on the CDAA forum and someone was kind enough to offer to analyse those samples at work. Turned out it was 1.9% CO2 at the surface, and 19.5% O2. At the top of the rockpile it was 1.2% CO2 and 19.9% O2.
So, if you have the option of returning later, I recommend collecting some gas with a plastic Pepsi bottle, for later testing. They are, afterall, designed to hold CO2-soaked liquid.
Cheers
Peter
Lower CO2 in the air chamber?Quote:
Originally Posted by PeterBuzzacott
Hi Forrest
Both samples were collected in the chamber between sumps 1 and 2. As we approached the lake at the end of sump 1 I unscrewed the cap off the bottle, lifted it up through the surface upside-down so the water would pour out and collected a gas sample from an inch above the surface of the lake in the chamber. Then, I emptied the second bottle of water (and collected gas) at the top of the rockpile. CO2 being denser than oxygen, there was higher CO2 and lower oxygen by the lake, compared with at the top of the rockpile.
Ah, you meant the surface in the air chamber! I thought you meant outside the cave.Quote:
Originally Posted by PeterBuzzacott
BTW Dave were is my lighter ;))...Quote:
Originally Posted by DaveP
On symptoms, we have seen smokers can sometimes fail to notice the effects of elevated CO2 for longer than non-smokers.
I suppose they're already accustomed to higher levels of CO2, so it doesn't really feel out of place for them. Or their respiratory drive is already impaired in that respect so it takes more exposure to get a reaction. Hardly clinical, but we've observed it on more than one occasion.
your lighter died eric, the air was safe since we breathed it for 40 mins, but water is acid :)
I only had the balls to breathe that air for 5 minutes... and out of there ;)Quote:
Originally Posted by Neptuno