|Carbon Monoxide in Tents #3932|
Back To Discussion List Written: 2012.12.11 by: Dean Richards
For various reasons, I've become interested in the potential dangers of carbon monoxide in tents, due to running stoves. I've done some reading and thought some would appreciate the summary. More than 10 people die every year in BC from CO poisoning. How much of that is from camping stoves I do not know. I am mostly concerned about liquid fuel stoves in tent, but the principles still apply to solid fuel stoves in cabins.
Here is a link to a list of stoves, in case you have one of the ones listed:
The top link should be Part 3, click on that. On page 2 and 3, the levels of CO are indexed in ppm. Pages 3 and 4 show the levels of each stove for different levels of flame and the ppm. See if yours is abnormally high. I'd say less than 50 and you should need to worry too much. That's just my interpretation though. Depends on the application of course.
Basic primer on the dangers of CO:
-CO is produced by incomplete combustion of fuel
-The primary variable that increases CO from the stove, is the flame getting quenched prematurely, therefore the clearance between the burner and the pot is key
-Yellow flames put out roughly double the CO that blue flames do. Simmering on the lowest setting is often the worst though
-The risk gets worse with altitude, since O2 is less and therefore incomplete combustion increases
-CO bonds to the hemoglobin in your blood 200 times more readily than O2. Serious business!
-It takes 4-5hrs of fresh air at sea level, for half the CO in your blood to get out
-Snow caves and igloos are the worst for ventilation, but certain tents, especially when the wind is low, can be bad too. The 6 inches of waterproof material at the bottom of the tent means no air is coming in or out at the level you sleep at
-Butane/Propane mixes produce less CO than other liquid fuels. Kerosene is by far the worst
-A pot above the flame can produce up to 10x more CO than no pot
What you can do to reduce the risk:
-Make sure there are at least 2 good vents, one as high as possible, the other as low as possible and aim for the vent to be at least 50cm square in area
-Occasionally open up the doors in your van, or the doors of the tent to allow maximum ventilation for a few minutes. Get out occassionally to see if any symptoms manifest. Hard to know if you're losing coordination if you're sitting in your tent.
-Using your stove for long periods of time to heat your space is sketchy, but if you are doing this, make sure the flame is blue, not covered by a pot
-If you have the choice, butane/propane mixes are safer than white gas
-Use a stove with at least 12mm clearance between he top of the burner and the bottom of the pot
-Stay well hydrated
#1645 - 2012.12.20 Robin Tivy - We always cook in the vestibule
I've been on hundreds of trips over 20 years where we cook in the vestibule with a MSR white gas stove. The reason is it saves considerable fuel to have shelter for the stove. We light the stove with the vestibule open, then mostly close it while cooking. For ventilation, there is always a thin space between the vestibule and the ground all the way round at the bottom of the tent. However since heat rises, the burned gas is usually going into the tent, I would think. So I suspect that air is not really good at the top of the inside of the tent. I suppose it would be good to make sure the top vent of the tent is open. I've never noticed any problem, but it's good to be aware. We've never used the stove in the main body of the tent, and never use it as a heater to keep the tent warm. It is only for cooking. And never used it when the tent was covered with snow.
#1644 - 2012.12.18 Andrew Wong - Good discussion Question: several years ago I snowshoed to the Wendy Thompson Hut and went into the cabin to have lunch, but was driven out by the intense smell of kerosene from the stoves that people had going. Would that be a sign of incomplete combustion and therefore a potentailly high level of CO in the cabin? Or is that normal for a kerosene stove? Just wondering, thanks.
I read an article about two skiers who were incapacitated by CO poisoning on the Wapta Traverse several years ago. The pair had taken shelter in a snow cave to wait out a storm and even though they had followed normal conventions for stove use, there wasn't enough ventilation in their shelter. Eventually the roof of their cave collapsed but due to CO poisoning they were unable to escape. The coroner's report had recommendations to change the standard/normally accepted practice for stove use. Unfortunately I can't recall which magazine the article was in--Explore?--but it would be useful reference material.
Question: several years ago I snowshoed to the Wendy Thompson Hut and went into the cabin to have lunch, but was driven out by the intense smell of kerosene from the stoves that people had going. Would that be a sign of incomplete combustion and therefore a potentailly high level of CO in the cabin? Or is that normal for a kerosene stove? Just wondering, thanks.
#1643 - 2012.12.15 Chris Ludwig - Hanging stove use
I have for many years used a Bibler hanging stove in a Bibler Fitzroy single wall tent. I have felt safe doing so by opening/venting the fumes at the tops of both doors. My main concern is actually the tent catching on fire. Perhaps this is a little paranoia on my part. I always clip my stove into the interior tent poles with a carabiner. I believe you can no longer purchase a Bibler hanging stove due to liability concerns? A double wall tent is perhaps much less safe than a single wall tent for a variety of reasons. It is sure nice to heat the tent in winter despite the dubious nature of this use. Good topic for an article (and informative).