Some questions about excess gas

March 6, 2013 3:24 PM

I have dropped and broken a 20 pound container of CO2 in my basement. It was terrifying. While I air out the basement, I have a few questions:

- other than bringing a big fan in and having the doors open, is there anything else that will help disperse this gas faster?
- the air intake for my furnace is also in the basement. Is this a problem?
- are there any other sorts of things that might be affected that I am not thinking of? The only thing I can kind of think of is that it will slightly acidify the water in the toilet and floor drains, but that isn't actually a big deal.

[the tank was behind a blanket and was knocked over when I dropped the tabletop I am making. It did not rocket through any walls like in mythbusters.]

posted by Acari to home & garden (15 answers total)

Stay out until you can get some exhaust fans to vent the room. CO2 is heavier then air so could in theory stick around. The only other thing I would check on is if you have a gas furnace or water heater with a pilot light it could of been extinguished if enough air got displaced...though even that is a stretch.
posted by Captain_Science at 3:34 PM on March 6 [1 favorite]

20 pounds of CO2 at standard temperature and pressure takes up 174 cubic feet. Assuming your basement is 800 square feet and has 8' ceilings, that's only 2.7% of the volume of the room.
posted by zsazsa at 3:43 PM on March 6

that's only 2.7% of the volume of the room

Which is about enough to kill you, by the way.
posted by ryanrs at 3:46 PM on March 6 [3 favorites]

Yeah, I'm trying to blow with a big fan up the steps to get that heavy gas moving...

I checked the manual for my furnace and it says that it has a thinger to test if there is enough oxygen available, which I suppose was my main question.

[CO2 is not a sneaky killer, ryanrs, or at least not for humans. Almost any other gas would be more worrisome to me, healthwise.]
posted by Acari at 3:57 PM on March 6

Some numbers on CO2 toxicity. Seems that 3% isn't immediately dangerous, but definitely really bad.
posted by zsazsa at 3:59 PM on March 6

Which is about enough to kill you, by the way.

True, but if OP's been running a fan to bring in outside air for even a few minutes, the concentration would have dropped even further. I'd just open a window and run a couple of fans, one in the window and one at floor level pointing somewhat upward for an hour and call it fine.
posted by barc0001 at 3:59 PM on March 6

You need a CO2 detector (or a few) in the areas where you live and breathe. Maybe it's fine, but it's not really a chance that I would want to take. The probability seems small, but the consequences are large.
posted by kamikazegopher at 4:00 PM on March 6

CO2 is not a sneaky killer, ryanrs, or at least not for humans

I'm not sure what you mean by this. It makes you drowsy then suffocates you. Seems pretty sneaky to me. Carbon dioxide is way more dangerous than simple displacement asphyxiants like nitrogen or argon.
posted by ryanrs at 4:04 PM on March 6 [1 favorite]

I think you posters who are super concerned about this are confusing CO (carbon monoxide) with CO2 (carbon dioxide): CO2 triggers the breathing reflex (more so than lack of oxygen), but is otherwise pretty mundane. CO makes you drowsy and is nasty shit. If the CO2 is still around you'll be wanting to breathe more.

I'm in the "get a fan going, check your furnace pilot light" camp.
posted by straw at 4:13 PM on March 6 [9 favorites]

For clarification purposes, signs and symptoms of hypercapnia with associated volume % in air. Fans and open windows should do the trick.
posted by two lights above the sea at 4:17 PM on March 6 [1 favorite]

The CO2 is probably not evenly distributed--Because it's heavier than air, the area near the floor will have a higher (possibly dangerous) concentration. It sounds like this much CO2 is enough to cover the bottom few inches of your basement, and with the mixing from the fans it might be deeper than that by some multiple but at a lower concentration.

In any case I think it's good to be cautious, and consider whether there are sumps, depressions, etc. where a pet or child could end up and suffocate.
posted by jjwiseman at 4:38 PM on March 6

Carbon DIoxide triggers the breathing response. If there's a lot of CO2, you'll find yourself breathing really fast.

Carbon MONoxide is super dangerous because it knocks you out. For obvious reasons, they don't make tanks full of carbon monoxide.

You could also bring a candle down there, and see if it snuffs out. If the candle burns, you're probably okay.

Big fans should do it.
posted by musofire at 8:12 PM on March 6 [3 favorites]

For obvious reasons, they don't make tanks full of carbon monoxide.

they most certainly do, just like all industrially useful gasses.
posted by russm at 1:48 AM on March 7 [1 favorite]

I'm not sure what you mean by this. It makes you drowsy then suffocates you. Seems pretty sneaky to me. Carbon dioxide is way more dangerous than simple displacement asphyxiants like nitrogen or argon.

But you won't notice displacement asphyxiation until seconds before you lose consciousness.
posted by atrazine at 2:34 AM on March 7

Thanks!
A few wrap-up things:
-No pets, no children
-I was going to test the water sitting in the toilet the next day with a pH strip, but we are an 'if yellow then let mellow' family so I lost that chance.
-CO2, though heavier than air, doesn't really stratify in a significant way [at the scale of a basement you won't really get a 'bottom layer' of CO2]
-Flames will still burn at very high [like... double digit percentages] CO2 concentration, so a while flame is a good test for the presence/absence of oxygen it is a less good test for CO2 levels except for extreme cases. The flame will burn slightly differently as the concentration of CO2 increases, but I think that is a thing you need a lot of experience to be sure about.

Repairing the broken regulator [a $12 part broke, which is lucky] has given me the chance to get the fittings to make a cap to carbonate a 2L bottle of whatever, so hey!

Also the tank now has a 'leash' to keep it from falling down, which I can't even believe I didn't put there before.
posted by Acari at 8:31 AM on March 9 [2 favorites]