Will I wake up, in sealed tents?

Yes, a snow-covered tent can kill. There’s a detailed story that I read recently (probably in AINAM) about that happening (not a case involving a stove, either).

Google on “snow tent carbon dioxide”. You’ll find some interesting articles.

http://www.wemjournal.org/wmsonline/?request=get-document&issn=1080-6032&volume=015&issue=03&page=0157

http://www.vnrs.org/Issues_etc/Deadly_White_Blanket/deadly_white_blanket.html

“sleepers will simply lose consciousness and die”

are you generally concious when you’re asleep ;)

I don’t have any info relevant to tents but hypercapnic (high CO2) people are generally sleepy people so it would make sense that you could fall asleep and if your tent somehow was sealed by snow or ice and no longer gas permiable you could use up the O2 and suffocate.

Fill your tent with potted plants to use up the Co2 :-)

Seriously though, I haven’t done any net research but there will probably be some type of small Co2 detector that your could maybe take with you if if it that much of a problem.

Just to add to the mixture, I read an article several years ago about really huge guy, that slept in a small enclosed space and died during the night from the amount of methane he produced whilst breaking wind in his sleep. So, depending on your diet, Co2 might not be the only problem you face if it snows!!!!!

I had a quick look on the net, this came up as a battery powered small oxygen alarm and monitor with lcd display to show surrounding levels. 200g. (I’m guessing that would achieve the same ends as oxygen drops the co2 rises)and that unit will run for 2 years continuously. If your in snow country this might be a remote possibility of happening (I dont know the figures) but the end result is as bad as it can get. Might be worth the 200g for peace of mind.

Alternatively the same company offers the same unit but for Co2. No I idea about price, probably expensive but there must be other units out there!

http://www.wessingtoncryogenics.co.uk/Oxygen.htm

I once had something similar happen to me though it involved rain not snow. I was on a Scout outing as a kid, using one of those canvas spring bar tents. It was raining very hard all night. I awoke in the middle of the night feeling like I could not breath. I woke my tent mate up because he was breathing real heavy. It occurred to me that the rain had sealed the tent. I opened the door a crack to let some air in, which also let some rain in, but it was better than suffocating. The situation was a real surprise to me. In my case I woke up struggling to breath. I assume my friend would have woken up but I don’t know.

Hmmm… my next tent, I’m going to look for one with a protected ceiling vent or two…

CO2 is heavier than air, it thus displaces air on the bottom of your structure, suffocating you. A sleeping adult uses about a quarter of a litre of oxygen per minute. Thus it will not take long in a small tent or snow cave with other mates present. Lowering oxygen levels in the blood produce a type of breathing called Cheyne-stokes syndrome, if memory serves (and I may have mispelled it), where one may not breathe at all for many seconds, and then gasp for air. If this mechanism does not wake you, you may become unconscious and perish.

Doesn’t the Vice President have this syndrom?

Bernard, I don’t know the answer to your questions but I personally won’t use a tent that doesn’t have a large vent up on the fly for that very reason. A few months ago I was testing my sleep system inside a small one-person tent in a snow storm. During the night swirling winds drifted the snow all around the perimeter of the tent blocking off the ventilation under the fly. The top of the inner tent was left unzipped and open to the peak vent. An occasional blast of cold air and spindrift entered the tent, waking me up. I figured that this was better than being smothered in CO2.

> Do sleepers wake up from the build up of Carbon Dioxide in the blood?

In general a high level of carbon DIoxide (CO2) will cause a near-panic reaction. In general you WILL wake up, desperate for fresh air. In fact, hospitals use ‘carboxygen’ to revive anaesthetised people. It’s a mix of oxygen (or maybe air) and carbon dioxide.

However, a build-up of carbon MONoxide (CO) will NOT wake you up, and at sufficient concentration WILL kill you. You can get significant levels of CO from trying to run a stove in a sealed volume.

So, make sure there is a vent at the top of your tent. Yeah, you may lose some heat out of it, but better you be cool than stone cold (dead).
If you want to cook in your tent, that’s fine. Many of us do this all the time. But make sure there are two OPEN vents: one at the top and one (preferably) at the floor level. In snow country, this may need monitoring while you are cooking.

What size vents do you need? A slot 8″ long by 1″ wide is fine for a small canister stove. Larger if you wish of course.

Cheers

Just in relation to the above Carbon Monoxide poisoning. Here in the UK a few years ago, two firefighters collapsed from carbon monoxide posioning. Their fire engine was parked in an alley between to large brick buildings. The engine was running to power the pumps etc. Now, despite being outside in the open air, there was very little breeze and the carbon monoxide just hung in the air and both men collapsed before they could do anything about it. Luckilly, both survived.

Also, my father and a colleage of his also collaped in a small tent some ten years ago. A small generator was nearby and the fumes from that entered the tent without them realising and again both collapsed. (Both had been awake, my father suddenly realised that his colleague was acting strange and theat he himself was a bit unwell. His colleague collapsed, my father managed to drag his colleague out of the tent before he himself collapsed. Luckilly a passerby found them both unconscious just outside the entrance to the tent. Both nearly died and needed to be put under pressure (Similar to divers) to rid their bodies of the gas.

So, its a topic quite close to my heart. The medics I spoke to in the hospital told me that Carbon Monoxide, is tasteless, odourless etc. It builds up in the body and once their stops the bloods ability to absorb oxygen. It can build up quickly or over a period of time depending on the source. The body finds it hard to rid itself of the gas and so, even a little gas means it can effectlive be “Drip Fed” so to speak until you get to the point where oxygen uptake isn’t sufficient for the activty your engaged in, which if your sleeping and the concentration is high, means you don’t get enough oxygen into the blood to sustain your vital organs.

If your found, giving oxygen can only help so much and urgent medical attention is needed.

For these reasons, if cooking in your tent, not only do you need ventilation but you need a through breeze as well. Sounds obvious but then again it caught the firefighters out and my father!!!

Roger,

Thanks for the post. The “in General” is not 100%. One way I translate this to an audience is to say to them, “OK, this season, if you and all your friends, and their friends go out and there are only one of you dead from a sealed tent, is this acceptable a safety % ?”

Yes, many times we wake up, it is IMPORTANT for me at least to remember I may not wake up.

I Think Roger got it right. The feeling you get when your body screams at you to take a breath is the result of carbon dioxide buildup rather than oxygen depletion. I imagine you would wake up gulping for air the way you would if someone gently put a pillow over your head.

This concept is outlined in the avalanche scenario in Peter Stark’s book “Last Breath.”

John, please correct the “typo” in you last post. You obviously meant to say “carbon dioxide”, not “carbon monoxide”. Just one little oxygen atom makes all the difference.

Oops, what a silly mistake–and after the above clarification that carbon monoxide is a silent killer.

Here I am trying to clarify things and just made it more confusing. Thanks for the extra set of eyes!

> The “in General” is not 100%.
I don’t think we have had a single death in Australia from carbon doxide in a small tent. I would be pretty confident myself.

But the key thing here is that you should NEVER let your tent get completely sealed. Never. Always have a vent, and keep it open. If this means you have to wake up several times in the night and clear the vent, do it. If you are cooking, make sure you have two vents, and a through flow.