Risks of CO2 on Board

[Dockhead]

I'm thinking about buying a soda machine to make my own tonic water on board (and cola, etc.).

Got me thinking about whether it is dangerous to keep CO2 on board.

I believe fairly modest concentrations of CO2 can kill by asphyxiation.

And as everyone knows, CO2 is quite heavy, so will collect in a boat hull like propane does.

What think ye?

[a64pilot]

I think put it out there with the propane, and you'll have no problems, or have small cylinders of C02

[Dockhead]

Originally Posted by a64pilot

I think put it out there with the propane, and you'll have no problems, or have small cylinders of C02

I don't have room in the gas locker, which is tailor-made for a pair of 4.5kg Calor gas bottles. I do keep petrol behind my swinging transom platform -- could keep it there. But steel cylinders will rust there.

I suspect that a standard Sodastream gas bottle has enough CO2 to be dangerous.

EDIT: It's 14.5 ounces. I wonder how dangerous that amount of CO2 is in a boat interior? It's 0.21 cubic meters. That's enough to spoil 210 cubic meters of air (OSHA limit of CO2 concentration is 1000ppm). That's more air than I have in my boat.

[colemj]

This is a joke, right? I mean, CO2 cylinders are used and stored regularly in enclosed areas. They are pretty much ubiquitous in most people's lives without them even knowing it.

Yes, all the safety nuts will probably jump on this with dire warnings about the possibility of the tank letting loose while you sleep and suffocating you.

But really?????

Just call it a fire extinguisher, and it is immediately made extremely safe and desirable to have within reach.

Mark

[David M]

I have a 40 pound fixed CO2 system onboard. While being serviced, one year I got to shoot it off into the engine space. It did indeed go straight down into the space. The fire extinguisher tech said, ok now go ahead and put your nose down there and sniff it. WHEW...it was at least ten times stronger than the CO2 you feel from a carbonated drink. It was quite painful.

What I am getting at is that you will know it if you are breathing CO2 long before it becomes a suffocant. Even if you are sleeping, the pain in your sinuses would wake you up long before you would suffocate.

[a64pilot]

Ask any Re-breather diver if C02 is dangerous. Good point about the fire extinguisher though.

[a64pilot]

Originally Posted by David M

What I am getting at is that you will know it if you are breathing CO2 long before it becomes a suffocant. Even if you are sleeping, the pain in your sinuses would wake you up long before you would suffocate.

No, you will not

[a64pilot]

Symptoms of Carbon Dioxide Intoxication and Poisoning

deeper breathing
twitching of muscles
increased blood pressure
headache
increased pulse rate
loss of judgement
labored breathing
unconsciousness (occurs in under a minute when CO2 concentration rises about 10%)
death

[Dockhead]

Originally Posted by colemj

This is a joke, right? I mean, CO2 cylinders are used and stored regularly in enclosed areas. They are pretty much ubiquitous in most people's lives without them even knowing it.

Yes, all the safety nuts will probably jump on this with dire warnings about the possibility of the tank letting loose while you sleep and suffocating you.

But really?????

Just call it a fire extinguisher, and it is immediately made extremely safe and desirable to have within reach.

Mark

Not a joke! CO2 is really quite dangerous.

http://www.blm.gov/style/medialib/bl...dat/25apxC.pdf

There was a case some years ago where more than a thousand people were killed when CO2 came out of a volcanic vent. Breathing 30% CO2 causes convulsions, coma, and death.

See also: CO2 » Maritime Accident Casebook

"Unplanned releases of carbon dioxide can have tragic results. It can extinguish lives as easily as it can put out fires so it’s vital to ensure that the CO2 cylindre room is isolated when someone’s working on the fire extinguishing system"


http://www.epa.gov/ozone/snap/fire/co2/co2report.html

At concentrations greater than 17 percent, such as those encountered during carbon dioxide fire suppressant use, loss of controlled and purposeful activity, unconsciousness, convulsions, coma, and death occur within 1 minute of initial inhalation of carbon dioxide (OSHA 1989, CCOHS 1990, Dalgaard et al. 1972, CATAMA 1953, Lambertsen 1971). At exposures between 10 and 15 percent, carbon dioxide has been shown to cause unconsciousness, drowsiness, severe muscle twitching, and dizziness within several minutes (Wong 1992, CATAMA 1953, Sechzer et al. 1960). Within a few minutes to an hour after exposure to concentrations between 7 and 10 percent, unconsciousness, dizziness, headache, visual and hearing dysfunction, mental depression, shortness of breath, and sweating have been observed (Schulte 1964, CATAMA 1953, Dripps and Comroe 1947, Wong 1992, Sechzer et al. 1960, OSHA 1989). Exposures to 4 to 7 percent carbon dioxide can result in headache; hearing and visual disturbances; increased blood pressure; dyspnea, or difficulty breathing; mental depression; and tremors (Schulte 1964; Consolazio et al. 1947; White et al. 1952; Wong 1992; Kety and Schmidt 1948; Gellhorn 1936; Gellhorn and Spiesman 1934, 1935; Schulte 1964). Part I of Appendix B discusses human health effects of high-concentration exposure to carbon dioxide in greater detail.

Kills you in less than a minute at concentrations above 17%!!!

[a64pilot]

Originally Posted by Dockhead

EDIT: It's 14.5 ounces. I wonder how dangerous that amount of CO2 is in a boat interior? It's 0.21 cubic meters. That's enough to spoil 210 cubic meters of air (OSHA limit of CO2 concentration is 1000ppm). That's more air than I have in my boat.

From what I can tell, it seems that about 10% is the point where you go unconscious in less than a minute and will die.
If I understand the math, 10% is 21 cu meters, still more than the area of a common boat? I don't want to sound like an idiot, but my JD 410 backhoe's loader bucket is 2/3 yd, which is about all an American pickup can handle, so I'm thinking the interior of a boat isn't 30 time that?
Notice the question marks, I'm asking if I'm right.

[a64pilot]

Wait, is 10% 2.1 cu meters?

[chris95040]

Dockhead,

This:

http://www.oregon.gov/osp/SFM/docs/C...hartPublic.pdf

Verified your numbers for me (well, I got 0.245 cubic meters from 14.5 oz )

In my opinion, I think this is a good way to approach the problem. I did similiar arithmetic figuring out how big of a liquid argon tank I'd need to push bulk aging wine from one storage vessel to another.

But I don't think you want to go with 1000PPM - the cannister failing is something that is likely never going to happen, so the figures for "general discomfort" or "occupational overexposure" aren't relevant - if it happens once, you'll throw out the soda stream and go back to soda bottles. I think you just want to avoid deadly exposure, which according to this:

Carbon Dioxide Comfort Levels

is much higher. 30,000 PPM for some intoxication and difficulty breathing, 100,000 PPM you might go unconscious. 100,000 ppm, thats 10% right, so as long as only one busts open, and you have more than 0.245 * 10 = 2.45 cubic meters of cabin room, hey, you just might survive it.

That ignores how it may settle if it's heavier than air - but if you have a safe margin beyond 2.45 cubic meters of bilge and floorspace for it to occupy, and you don't sleep on the floor, you're probably cool. And if you climbed into a bilge full of it, my *hunch* (with nothing to back it up other than the knowledge that inert gas blanketing of wine is way easier with Argon than the far lighter CO2) is that you'd get enough air mixing for this to not be an issue anyways.

There must be some other practical reason why this is simply /never/ a concern, folks have those things in their pantries etc. with no thought to it.

[Dockhead]

Originally Posted by chris95040

Dockhead,

This:

http://www.oregon.gov/osp/SFM/docs/C...hartPublic.pdf

Verified your numbers for me (well, I got 0.245 cubic meters from 14.5 oz )

In my opinion, I think this is a good way to approach the problem. I did similiar arithmetic figuring out how big of a liquid argon tank I'd need to push bulk aging wine from one storage vessel to another.

But I don't think you want to go with 1000PPM - the cannister failing is something that is likely never going to happen, so the figures for "general discomfort" or "occupational overexposure" aren't relevant - if it happens once, you'll throw out the soda stream and go back to soda bottles. I think you just want to avoid deadly exposure, which according to this:

Carbon Dioxide Comfort Levels

is much higher. 30,000 PPM for some intoxication and difficulty breathing, 100,000 PPM you might go unconscious. 100,000 ppm, thats 10% right, so as long as only one busts open, and you have more than 0.245 * 10 = 2.45 cubic meters of cabin room, hey, you just might survive it.

That ignores how it may settle if it's heavier than air - but if you have a safe margin beyond 2.45 cubic meters of bilge and floorspace for it to occupy, and you don't sleep on the floor, you're probably cool. And if you climbed into a bilge full of it, my *hunch* (with nothing to back it up other than the knowledge that inert gas blanketing of wine is way easier with Argon than the far lighter CO2) is that you'd get enough air mixing for this to not be an issue anyways.

There must be some other practical reason why this is simply /never/ a concern, folks have those things in their pantries etc. with no thought to it.

Thanks -- that seems like a sensible and useful approach based on valuable practical experience.

I have a deep bilge, but I doubt if it will hold more than 1 cubic meter.

But you might be right -- if it tends to settle rather than propagate through the space, maybe it's not too dangerous if we know not to lie on the cabin sole. As long as we're aware that there was a breach!

Maybe a CO2 alarm is all that is required, plus being careful not to have more than one of those cylinders inside at a time. Keep the others in the gas locker or behind the transom platform.

[chris95040]

Originally Posted by Dockhead

Maybe a CO2 alarm is all that is required, plus being careful not to have more than one of those cylinders inside at a time. Keep the others in the gas locker or behind the transom platform.

That seems sensible!!!

[a64pilot]

Ever seen a C02 alarm? I ask as I believe only one re-breather monitors C02 and the reason given is it's real difficult to get a C02 monitor to live in a humid environment.
May not be easy to find one?