New Caver with Oxygen levels questions

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New Caver with Oxygen levels questions

Postby Fear Unfathomed » Oct 27, 2010 3:46 am

Hello everybody!

I looked through some of the posts but didn't find anything that exactly addresses my question. It is probably out there in cyberspace somewhere, so sorry if this is a repeat topic/question.

I am new to caving and I have been in only 2 caves. One was with a group of about 20 people and I have only been in there once. The other cave I go to rather frequently and have been down there with a couple friends and and I have been down there with up to 11 people. Tonight, there were 11 of us (the largest group previously was 9) and we were in a commonly explored and well explored cave. As we kept going down paths I had been down before, we all noticed a difficulty in breathing. Then it got to a point where 3 people wanted to bail, so I led the way out and before I know it, the rest of the group (7 people) had bailed too because they reached a place where they absolutely could not breathe - they said it was like they hit a wall. The areas we were in you could fully stand up in, but we were surrounded by lots of pools of water. I have been even deeper in this cave than where we went tonight, and I have never experienced that - not even with the group of 9. Now, this group tonight was probably more excited and was therefore breathing more and breathing harder, but what are the usual reasons for this? I read somewhere it means there could be a high amount of decay. Or was it just that everyone was sucking up all the oxygen? However, we were in such spacious areas, I do not know how much of a role that can actually play. I am just curious as to the possible causes since I have been down there many times before and never experienced it.

Thanks!

Lauren
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Re: New Caver with Oxygen levels questions

Postby paul » Oct 27, 2010 6:38 am

Definitely sounds like low levels of Oxygen (O2) - probably coupled with high levels of Carbon Dioxide (CO2). There are several caves here in the UK where periodically this happens and I have experienced the symptoms myself a few times.

Usually the cause is decaying organic matter but can also be due to cavers using up the available O2 while breathing. Of course this depends on the volume of air available and the number of cavers. As CO2 is heavier than air it tends to collect in low areas so it is possible for it to build up, say at the bottom of a shaft (or pit as you say over there). It can also be experienced at the end of a blind passage.
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Re: New Caver with Oxygen levels questions

Postby captnemo » Oct 27, 2010 12:27 pm

Suprisingly enough the urge to breathe is not usually driven by oxygen but as Paul mentioned by co2 levels. The exception being in people who have been exposed to high levels of co2 for extended periods of time (i.e. smokers, copd patients). Thus high levels of co2 can trigger a feeling of being unable to breathe even when there is plenty of oxygen. While working as a comercial diver I experienced this often- heavy work would cause co2 build up from my exhalations and I'd have to 'vent' (open a free flow valve) to allow fresh air to force the stale air out of my helmet. Different people describe the symptoms differently, but headaches, stuffiness, shortness of breath, a heavy feeling, are common descriptions of being in a high co2 envionrment.
While there may be plenty of oxygen, high co2 levels are dangerous as a condition known as hypercapnia occours and blood chemistry changes. Symptoms of high levels of carbon dioxide in the blood include flushed skin, muscle twitches, elevated heart rate, shortness of breath and minor mental impairment such as confusion.

In caves elevated co2 can occour from chemistry in the minerals of the cave, but more likely as Paul mentioned from organic sources, rotting vegitation, decomposing bat guano, or the exhalations of a lot of cavers in a small space. And since it's heavier then oxygen it will settle into low lying spaces.
You should carry a lighter which you can use to quickly check for high co2 levels. It's not the most accurate test but it definetly works, and is cheap and easily available. Here's a picture Bill Frantz took of me in Lobatse cave where we experienced very high Co2 levels- note the large gap between the lighter and the flame Image just a few feet more into that passage and the lighter wouldn't light at all, definetly time to leave :)
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Re: New Caver with Oxygen levels questions

Postby Fear Unfathomed » Nov 5, 2010 5:35 am

Thanks! All of that information was very helpful and good things to keep in mind for future reference.

I appreciate it!
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Re: New Caver with Oxygen levels questions

Postby Scrivy » Dec 24, 2013 11:33 pm

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Re: New Caver with Oxygen levels questions

Postby shibumi » Dec 27, 2013 8:32 pm

And just for your fun, we have a long term project to sample O2 and CO2 levels in as many caves as possible, with some monitoring of a few caves on a regular basis. You ca find the raw data here:

http://www.bucknercave.org/allgasdata.php

I apologize that it is not in a more useful format, configuring databases is not our strong suit. And we have a bunch more data that hasn't been entered yet.

In the next phase of our project we are purchasing monitors we can send out across the country so if there's caves that people want to check we'll have that available soon.
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Re: New Caver with Oxygen levels questions

Postby caverdan » Dec 30, 2013 11:59 am

shibumi wrote:In the next phase of our project we are purchasing monitors we can send out across the country so if there's caves that people want to check we'll have that available soon.

We have a cave in Williams Canyon that has a passage that has been reported to have bad air in it from time to time. It is the lowest and closest passage to the water table. We have been talking (WCP Project)about putting some kind of monitoring device in there for several years now, but it has been cost prohibited to do so. This is a cave we will more than likely be using during the 2014 NCRC week long class. A) are you coming this Spring? and B)would you be able to bring one with you?
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Re: New Caver with Oxygen levels questions

Postby shibumi » Dec 30, 2013 12:36 pm

caverdan wrote:
shibumi wrote:In the next phase of our project we are purchasing monitors we can send out across the country so if there's caves that people want to check we'll have that available soon.

We have a cave in Williams Canyon that has a passage that has been reported to have bad air in it from time to time. It is the lowest and closest passage to the water table. We have been talking (WCP Project)about putting some kind of monitoring device in there for several years now, but it has been cost prohibited to do so. This is a cave we will more than likely be using during the 2014 NCRC week long class. A) are you coming this Spring? and B)would you be able to bring one with you?


I'll be there of course (I sorta have to be ;-) and I'll have the monitors with me.

Lee Boop has some experience with long term in situ monitoring and datalogging, she and I have talked a bit and her experience is that it is difficult to find a monitor that can handle the long term environment.
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New Caver with Oxygen levels questions

Postby Ernie Coffman » Dec 31, 2013 1:10 am

Interesting that this is coming up again, but for a new caver who started the concern, it's right on topic. I remember Shibumi giving a presentation at the NSS Convention, in Colorado, and showing his instruments for checking on air problems. That was great! In California, the Mother Lode Grotto (MLG) raised funds and purchased instruments for evaluating the CO2 problems in several of the Mother Lode caves, one of which called "Dragon's Breath" was a real killer. Well, almost, anyway. One of the former members of MLG almost died down in it and had to be taken to the hospital. :yikes: There are several of the caves that have this problem and usually during a certain period of the year, when the rotting vegetation is doing its thing. I guess, in the past, we never recognized the problem as we must have gone caving in those caves at the right time of year, but...when you do hit bad air, you really know it and should get out of the cave before your body has problems. In fact, I'm surprised that Capt Nemo didn't mention the Bad Air Project that MLG was having for several years. Jim Hildebrand of Diablo Grotto and MLG, along with Kathy Lankford of the MLG were leading that project for awhile and there is a research project written up on it, somewhere. :clap: Hope this helps...and be aware by carrying a BIC lighter to test the air, if you think there's bad air in the cave that you're exploring. Better to be safe than to be a name on a list who might have survived.
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Re: New Caver with Oxygen levels questions

Postby leeboop » Jun 21, 2014 8:03 am

shibumi wrote:Lee Boop has some experience with long term in situ monitoring and datalogging, she and I have talked a bit and her experience is that it is difficult to find a monitor that can handle the long term environment.


We used 'cheap' CO2 sensors from CO2Meter.com (K33-ELG 0-10,000 ppm model). The salesman swore that they could handle the cave environment, though they were only guaranteed for conditions below 95% relative humidity (RH). Sure enough, after two weeks in each cave (we studied two caves) they shut off. We dried them out and then put them in a plastic shoebox, which I drilled holes in. I also placed a desiccant package (made by the now out of business company Zorb-It) which could be reused. So, every month, the desiccant package was replaced, and the soggy one dried out at the surface for a month. The sensors worked perfectly after we used this setup (see image, perhaps the upload worked?). In one cave, we recorded fluctuations exceeding 600 ppm in 10 hours.

I should also note that it's important, depending on the sensor technology, to correct for barometric pressure if you want to be accurate. These sensors are non-dispersive infrared, so I had to do that (it changed the reading by up to 40 ppm if I remember correctly).

To get RH, we used Tinytag Plus2 sensors. They recorded 100% RH the entire time.
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