# CO2 leak hazard?



## speakerguy (Sep 1, 2007)

I plan on having a 50 gallon planted tank with pressurized CO2 in my bedroom. Do they add any odor to CO2 or do they make CO2 gas detectors for the home? I would prefer not to die or anything in my sleep  Thanks!


----------



## Tex Gal (Nov 1, 2007)

You'd have to have the CO2 replace the air in your room to die. With a leak that large you'd hear it. I think you'll be fine. With a 50 gal the biggest tank I'd get it a 10lb tank.


----------



## ed seeley (Dec 1, 2006)

There's no hazard at all in having CO2 in a room. Typical atmospheric levels are about 385ppm. You're injecting maybe up to 30ppm into the tank so that's barely going to raise the normal levels. Even if your entire tank dumped into the room in one go the safe long term exposure levels are 5,000ppm (0.5%) and the level for short term harm is above 4%. These are taken from the COSHH (Control Of Substances Hazardous to Health) website over here and the NIOSH (US National Institute for Occupational Safety and Health).

The biggest danger IMHO is it falling over, smashing the regulator off and the cylinder becoming a rocket which can go through walls and all you have to do to avoid this (and it takes a LOT of force to snap off the regulator as I've knocked a tank over a couple of times before) is to secure the cylinder so it can't fall over.


----------



## jeff5614 (Feb 15, 2006)

Maybe a dropchecker by your bed?:lol:


----------



## Lionsfan (Jul 21, 2008)

It is a CO concentration you are worried about (and what is detected) and not CO2.
Hope this helps,
Scott


----------



## bigstick120 (Mar 8, 2005)

I think a lot of folks assume or mix up carbon monoxide with carbon dioxide.

CO highly toxic

CO2 not so much, you breath out CO2

http://en.wikipedia.org/wiki/Carbon_monoxide


----------



## speakerguy (Sep 1, 2007)

Former biochem student guys, so I know the difference between CO and CO2  One results from the complete combustion of a hydrocarbon, and the other from the incomplete combustion of one 

I just ran through the math and an entire 10lb tank dump into a sealed volume of my room at STP is only about 6% of the room volume. Seems really low to me, I'll have to check my math. CO2 can kill though, and it leaves a nice pink corpse like CO (although it takes much higher concentrations as mentioned).


----------



## ray-the-pilot (May 14, 2008)

speakerguy said:


> I just ran through the math and an entire 10lb tank dump into a sealed volume of my room at STP is only about 6% of the room volume. Seems really low to me, I'll have to check my math.


At 6% CO2 in your room you would be dead! Take my word for it. In a former life I managed a laboratory animal facility and the standard way to humanely euthanize an animal was with CO2. At low concentrations the animals fell asleep and died.

If your room is well ventilated you will not have a problem; so, sleep with one window opened a crack if your worried about it.


----------



## chagovatoloco (Nov 17, 2007)

jeff5614 said:


> Maybe a dropchecker by your bed?:lol:


Sleep with one of these just to be safe ainkille , sweet dreams


----------



## Indignation (Mar 9, 2008)

Get a rabbit. If the rabbit starts to freak out, time to open a window and run a fan. Animals that live underground are excellent low-O2 detectors.


----------



## hoppycalif (Apr 7, 2005)

Indignation said:


> Get a rabbit. If the rabbit starts to freak out, time to open a window and run a fan. Animals that live underground are excellent low-O2 detectors.


How do you train the rabbit to wake you up when it detects the CO2? (It is amazing how much good stuff you can learn on this forum!)


----------



## epicfish (Sep 11, 2006)

hoppycalif said:


> How do you train the rabbit to wake you up when it detects the CO2? (It is amazing how much good stuff you can learn on this forum!)


It would go crazy and bounce around the cage, which would trigger a trip-wire that you setup, which would pull on a string, dumping ice cold water over your head from a bucket you rigged to hang from the ceiling. Only thing was that you'd need to put fresh ice cubes in the bucket every night.


----------



## hoppycalif (Apr 7, 2005)

epicfish said:


> It would go crazy and bounce around the cage, which would trigger a trip-wire that you setup, which would pull on a string, dumping ice cold water over your head from a bucket you rigged to hang from the ceiling. Only thing was that you'd need to put fresh ice cubes in the bucket every night.


Thank you. I asked the wife and she said, go for it. So, what breed of rabbit do I look for? We have plenty of jack rabbits, big fellows, here by the river. If I can negotiate a contract with one, would he do?

OK, back to planted tanks.


----------



## BryceM (Nov 6, 2005)

In practical terms, this is not one of the top 100 things you need to worry about. A burst disk can empty a CO2 tank in a matter of seconds, but that's pretty rare and usually only happens if the tank heats up or is overfilled. If the safety disk does rupture, the resulting noise is loud enough to wake up dead people three blocks away. No human on earth would sleep through it.


----------



## davemonkey (Mar 29, 2008)

BryceM said:


> In practical terms, this is not one of the top 100 things you need to worry about. A burst disk can empty a CO2 tank in a matter of seconds, but that's pretty rare and usually only happens if the tank heats up or is overfilled. If the safety disk does rupture, the resulting noise is loud enough to wake up dead people three blocks away. No human on earth would sleep through it.


...and it still wouldn't be enough CO2 to kill you...

but just in case, I'm getting a rabbit.


----------



## BryceM (Nov 6, 2005)

Oh, I agree, not enough to kill you by a long shot...... maybe if you slept in a small, nearly air-tight closet with a 20 pound cylinder....... but maybe not even then.

I agree that standard-issue coal-mine canary rabbits would be a nice precaution. The stench alone would probably prevent deep sleep so you'd be pretty safe.


----------



## ray-the-pilot (May 14, 2008)

This is not really funny!

This is a fact! If you open a 10 pound cylinder of CO2 in your bedroom, the level of CO2 will go over 6%, which will kill you in 15 minutes. The only way to prevent this would be to have adequate ventilation.

Here is what the National Institute for Occupational Safety and Health (NIOSH) says about this: 
A CO2 level of 4 percent is designated by NIOSH as immediately dangerous to life or health.
http://www.inspect-ny.com/hazmat/CO2gashaz.htm

Those idiots who think that a rabbit will help don't understand that as the level of CO2 increases the victim falls asleep and doesn't jump around.

Here is something to think about! If you increase the level of CO2 in your aquarium to 60 ppm it will kill your fish. A 10 pound cylinder will increase the level of CO2 in your room to over 60,000ppm!

I never considered it until I saw this thread but after thinking about it, I don't think having a CO2 tank in your bedroom is a really good idea.


----------



## Newt (Apr 1, 2004)

Ray-the-pilot is correct. I am an EHS Manager and work with gases all the time. I believe a 10# CO2 tank holds ~42 cu ft of gas (w/o looking it up). How many cubic feet in the room you keep the tank in? I have a 20# tank but dont use it for this reason (simple asphyxiant).

NIOSH - 40,000ppm is IDLH (immediately dangerous to live and health). Normal amount in air is 300ppm and the permissable exposure level is 5000ppm, 8 hr TWA.

When I worked in the printing industry we had total flooding CO2 systems (enough to displace all the O2) for some of the rooms that held large amounts of flammable liquids. You had 15 seconds to get out once you heard the alarm and then it would dump up to 2200 lbs. One and a half breaths of CO2 and you were blacking out.


Pleasant way to go.....................if you're ready.


Why, that's no ordinary rabbit......................


----------



## Ultimbow (Sep 10, 2005)

Is your bedroom door air seal??? Most likely not so ther is no danger for your bed room to fill up from a slow leak unless the bottle explode. If that the case you will mostlikely die from the explotion. Wall are never air tight either light swith elcetric oultlet let air circulate. and if you are realy scare of it go to a store where they sell gas stove or gas system when you have one of those it is a law to have co2 detection system witch can be conect to a emegency central.


----------



## tropism (Jul 21, 2006)

Ultimbow said:


> ... and if you are realy scare of it go to a store where they sell gas stove or gas system when you have one of those it is a law to have co2 detection system witch can be conect to a emegency central.


Ultimbow, I think you're talking about CO detectors, not CO2.

They do make CO2 detectors, but as far as I can tell they're all more than $300, and most aren't designed for the average home user. It's hard to tell whether they are "complete" systems like we'd be looking for (a detector, readout of the current level of CO2, an alarm, and a power supply). I did find this system though (CellarSafe by Crowcon)... Out of curiosity I just called them. They said list price is $465 for the model without the backup battery or $560 with the backup (those prices are without the optional oxygen sensor). If you search on the net, make sure you look for "carbon dioxide" detectors -- most of the ones that come up when you search for CO2 detectors are just mislabeled CO detectors.


----------



## BryceM (Nov 6, 2005)

Rapid decompression of an entire CO2 tank is not something that you'll need to consult with your detector to know about. BOOM!!!!!! HISSSSSSSSSSSSSSSS!!!! People down the block will be wetting the bed.

Anything slower than a catastrophic failure won't dump enough CO2 to be in the least bit harmful. Like I said before - it's probably not in the top 100 ways for aquarium keepers to be killed by the hobby.

Electrocution from DIY wiring projects, venomous critters, bizarre aquatic infections, dangerous mold growing in the filth-soaked carpet, drowning during a collecting trip, slipping on a wet floor, anaphylactic reaction to bloodworms, etc, etc. etc. Those might deserve a mention, but accidental CO2 poisoning in a household from a hobby-size cylinder has NEVER been reported as far as I know.


----------



## tropism (Jul 21, 2006)

Oh, by the way, I didn't mean to imply that everyone needs to go out and buy a CO2 detector. Like Ed said in the 3rd post on this thread, I think the bigger danger is the tank getting knocked over and breaking off the regulator or valve. So if you have cats or dogs or kids running around, make sure the tank is secured.

As for CO2 levels in the room, it's pretty unlikely that you'd die from that. Yes, 6% is definitely a dangerous level, but you'd have to have the whole tank dump at once for it to be a problem in a regular bedroom. A catastrophic failure like that would definitely wake you up unless you are deaf or very nearly so. (If I was deaf I don't think I'd put a CO2 tank in my bedroom...) The only other problem scenario that I could see is if your bedroom is in a basement and you have NO ventilation. CO2 is heavier than air and pools in low areas. If you've ever played with dry ice (just solid CO2), then you can probably visualize what I'm talking about. Of course this also has the implication that the "6% of room volume" that the carbon dioxide would be taking up would be concentrated more towards the lower part of the room. (Don't know whether that's a good thing or a bad thing.) CO2 pooling in a basement still shouldn't be a problem with normal use though.

So to minimize risk (suggestions in order of increasing paranoia ): Secure the tank. Leave your bedroom door open a little when you sleep. Use a smaller tank (like a 5 lb, 2.5 lb, or even paintball cartidges -- of course that means refilling more often). If you're still worried, buy a CO2 detector.

-
To answer the other part of the original poster's question, No, they don't add any odors to industrial CO2. ADA does add some sort of "pleasant rainforest odor" to theirs, but I think they use small disposable cartridges which would probably cost you more than a CO2 detector over several years.


Edit: Yeah, what Bryce said.


----------



## Indignation (Mar 9, 2008)

ray-the-pilot said:


> Those idiots who think that a rabbit will help don't understand that as the level of CO2 increases the victim falls asleep and doesn't jump around.


Easy there, Ray. I was not actually advocating using a rabbit as a life-safety device. I was pointing that any burrow-dwelling animal has an acute sense of fluctuating O2 levels. _The more you know..._ 

If you are worried about this, then obviously don't use pressurized CO2. If you want to use it, do your homework. Make sure your tank has been hydrostatically tested, do a leak test on all your connections, secure your tank, and above all... use common sense.

I'm inclined to agree with Bryce... while this is not a dangerous hobby, if you do receive a life-threatening injury, there are far more likely causes.


----------



## ray-the-pilot (May 14, 2008)

Of course, everyone has to decide for themselves what is safe. So do the math:

A 10 # bottle of CO2 contains about 80 cubic feet of gas. Say you have a 9” x 12” x 8” room. Assume the tank releases over 15 minutes. With no exchange of air, the level of CO2 is:

80 cf / (9x12x8 cf) x 100 = 9.29% which is 2.32 times the level that NIOSH considers immediately dangerous to life or health.

So how much air do you need to exchange to bring it down to a safe level? 

CFM = RV/15 - .04/80/15* RV^2

CFM is cubic feet per minute 
RV is room volume

So for the 9” x 12” x 8” room

CFM = 864/15 - .04/80/15*864^2 = 32.7 cfm
If your room exchanges 33 cfm you will probably live. 

BTW here is something else to consider. CO2 is not an asphyxiate. It doesn’t kill by displacing O2. As the level of CO2 increases it binds to hemoglobin, which inhibits binding of O2. So even if there is adequate O2, excess CO2 will still kill you. That is why 4% CO2 is dangerous and N2, which is 80% of the atmosphere, is not.

Like I said before, I wouldn’t store a bottle of CO2 in my bedroom.


----------



## Newt (Apr 1, 2004)

ray-the-pilot said:


> BTW here is something else to consider. CO2 is not an asphyxiate. It doesn't kill by displacing O2. As the level of CO2 increases it binds to hemoglobin, which inhibits binding of O2. So even if there is adequate O2, excess CO2 will still kill you. That is why 4% CO2 is dangerous and N2, which is 80% of the atmosphere, is not.


Better check your msds again. It is a simple asphyxiant and does displace O2. That's why it is used to snuff out fires.
HCN kills by inhibiting O2 absorbtion.


----------



## hoppycalif (Apr 7, 2005)

CO2 is a little different from most gases in that it takes a lot of energy to convert it from a liquid to a gas. If you just blow the safety valve on a tank of CO2, what comes out is dry ice snow, not gaseous CO2. It takes time then for the "snow" to absorb enough heat energy to convert to a gas, and that chills down the air or whatever is providing that heat energy. The point is that it takes time to get that bottle of liquid CO2 turned into gaseous CO2. Meanwhile the room is getting colder and colder, so assuming you slept through the huge bang as the relief valve popped, you should awaken as you get cold.

Fire extinguishers are filled with liquid CO2 - at least that type of extinguisher is. When you pull the trigger on one you get a spray of CO2, dry ice snow, and a very loud noise. Those extinguishers are safe to use inside a house and generally you empty the tank when using it.

Just as gasoline is deadly dangerous - it burns and it isn't at all good to swallow or bathe in. But, we all use it, we get it on our hands, and we store the car in a garage, often attached to the living quarters.

Let's not get into how dangerous water is.:-k


----------



## chagovatoloco (Nov 17, 2007)

I have a ac unit in my bedroom and the door is sealed air tight. My 29 gallon aquairum is in their with a 5lb co2 bottle. It has been this way for the last two years, no deaths. Our houses all have gas that is just a deadly running through them. If we are smart and take precaution we will be just fine. I think there is more people killed by lighting than aquairum co2 bottles. Sure the danger is there but thousands of us manage to live every year with co2 in our homes and bedrooms. It is good to be safe but remeber "all work and no play makes jack a dull boy".


----------



## Revernance (Aug 20, 2007)

BryceM said:


> Rapid decompression of an entire CO2 tank is not something that you'll need to consult with your detector to know about. BOOM!!!!!! HISSSSSSSSSSSSSSSS!!!! People down the block will be wetting the bed.
> 
> .


ahahahahahahah wow.

I just wet my chair laughing....


----------



## Newt (Apr 1, 2004)

hoppycalif said:


> CO2 is a little different from most gases in that it takes a lot of energy to convert it from a liquid to a gas. If you just blow the safety valve on a tank of CO2, what comes out is dry ice snow, not gaseous CO2. It takes time then for the "snow" to absorb enough heat energy to convert to a gas, and that chills down the air or whatever is providing that heat energy. The point is that it takes time to get that bottle of liquid CO2 turned into gaseous CO2. Meanwhile the room is getting colder and colder, so assuming you slept through the huge bang as the relief valve popped, you should awaken as you get cold.
> 
> Fire extinguishers are filled with liquid CO2 - at least that type of extinguisher is. When you pull the trigger on one you get a spray of CO2, dry ice snow, and a very loud noise. Those extinguishers are safe to use inside a house and generally you empty the tank when using it.
> 
> ...


Fire extinguishers and our CO2 tanks are compressed CO2 not liquified. Dumping a CO2 extinguisher in a closed room with a fire would deplete the available O2 even faster. It's a good thing a lot of the posters here are not in charge of the health and safety of people working in manufacturing plants.


----------



## hoppycalif (Apr 7, 2005)

Newt said:


> Fire extinguishers and our CO2 tanks are compressed CO2 not liquified. Dumping a CO2 extinguisher in a closed room with a fire would deplete the available O2 even faster. It's a good thing a lot of the posters here are not in charge of the health and safety of people working in manufacturing plants.


Newt, you can't compress CO2 gas to more than about 700 psi (at room temperature) without it becoming a liquid. So, both our tanks and fire extinguishers indeed do contain liquid CO2. In fact if you have discharged a CO2 fire extinguisher you will have noticed that the spray is of solid CO2, not gas or liquid (CO2 can't be a liquid at atmospheric pressure). But, when you take your CO2 tank to be refilled, the first thing they do is open the valve wide open to let the gas out, and it comes out as invisible gas, not as CO2 snow. I do agree that I am not competent to be in charge of the health and safety of people working in manufacturing plants. I'm retired. But, before that I was in partial charge of the safety of people flying in commercial aircraft.:rofl:


----------



## ray-the-pilot (May 14, 2008)

Newt said:


> Better check your msds again. It is a simple asphyxiant and does displace O2. That's why it is used to snuff out fires.
> HCN kills by inhibiting O2 absorbtion.


Well faced with the evidence of an unreferenced MSDS, I guess it is useless to continue this discussion.

However, if anyone wants to find out about the hazards of CO2, check out this site:

http://www.emedmag.com/html/pre/tox/0500.asp
They say:
"In experimental models of acute CO2 poisoning, however, central nervous system and respiratory status deteriorated within seconds when FIO2 was maintained at normal levels, which suggests that CO2 is not just a simple asphyxiant but also has acute systemic effects."

BTW this tells the story of a guy who kills himself by walking into a room containing dry ice. No "Boom hisssss" just silent evaporation.

One other thing: CO2 kills by inhibiting O2 adsorbtion Check out this site:

http://en.wikipedia.org/wiki/Bohr_Effect

"in the presence of carbon dioxide, the oxygen affinity for dissociation of respiratory pigments, such as hemoglobin, decreases; because of the Bohr effect, an increase in blood carbon dioxide level or a decrease in pH causes hemoglobin to bind to oxygen with less affinity."

As I said before, you can do whatever you think is safe but at least try the calculations I suggested above to find out what the level of CO2 would be in your bedroom with a 15 minute release. Compare it to the NIOSH dangerous level. If you and your spouse (or whomever you are sleeping with), find that OK then by all means go for it!


----------



## Newt (Apr 1, 2004)

hoppycalif said:


> Newt, you can't compress CO2 gas to more than about 700 psi (at room temperature) without it becoming a liquid. So, both our tanks and fire extinguishers indeed do contain liquid CO2. In fact if you have discharged a CO2 fire extinguisher you will have noticed that the spray is of solid CO2, not gas or liquid (CO2 can't be a liquid at atmospheric pressure). But, when you take your CO2 tank to be refilled, the first thing they do is open the valve wide open to let the gas out, and it comes out as invisible gas, not as CO2 snow. I do agree that I am not competent to be in charge of the health and safety of people working in manufacturing plants. I'm retired. But, before that I was in partial charge of the safety of people flying in commercial aircraft.:rofl:


My Bad - Sorry.This is correct for CO2 under pressure - just re-read the msds. Nitrogen is the one I confused - had this at the 3 plants I've worked at. CO2 is still a dangerous gas to have indoors and should not be taken lightly. If you have enough to lower the O2 to less than 19.5% you are in trouble and at 16.5% you wont be around to bandy it about. The hose popping off the regulator could present an issue quicker than most would think. If you were involved w/ aircraft you sure must have known the dangers of materials packed in dry ice.

Ahhhh, to be retire. I'm jealous.


----------



## hoppycalif (Apr 7, 2005)

Next time you have the chance to look at solid CO2 - dry ice - notice that it doesn't explode in a mass of gaseous CO2. It just slowly, and very slowly at that, changes to a gas. This is because it takes a lot of heat energy to convert solid CO2, or liquid CO2 for that matter, to gas. And, the heat transfer from the atmosphere just isn't fast enough to convert much of it per minute. So, if it were possible, and it isn't, to dump a whole tank of liquid CO2 into a room it would take many minutes before all of that became gaseous CO2.

When I worked with aircraft, dry ice was used a lot for shrink fitting metal parts together, and a lot less for other purposes. In our repair shops there were always insulated containers containing dry ice for use by the mechanics for these purposes. No effort at all was taken to protect people from the CO2, and some guys liked to play with pieces of it during idle moments.

This is one of those theoretical dangers, which under extremely rare circumstances really could be dangerous. But, in ordinary life, having a tank of CO2 in the house, even in a closed up bedroom, just isn't more than a trivial hazard. (All of this doesn't include the danger involved if you break off the valve on top of the bottle, converting the bottle to a rocket powered missile.)


----------



## Newt (Apr 1, 2004)

It is called sublimation when a solid goes to a gas state w/o first converting to a liquid.

In my profession there are no trivial amounts. At the plant I am at now we have CO2 and liquid nitrogen for process cooling and generate hydrogen cyanide, sodium, sodium cyanide and CO that is given off from the manufacturing process. We spend lots of $$$$ for gas detection and the fear is always O2 depravation with CO2 and nitrogen leaks. I guess the 'fear' spills over to my private life. I also had a hose pop off the down stream side of the regualtor once when I first started using CO2; and the bottle (5# at the time) emptied out rather quickly. I now use a wire restraint on the hose barb connections (which were changed to a different style after this).


----------



## OhioPlantedtankguy (Aug 7, 2008)

BryceM said:


> In practical terms, this is not one of the top 100 things you need to worry about. A burst disk can empty a CO2 tank in a matter of seconds, but that's pretty rare and usually only happens if the tank heats up or is overfilled. If the safety disk does rupture, the resulting noise is loud enough to wake up dead people three blocks away. No human on earth would sleep through it.


Bet i could sleep through it! i have slept through my friends idea of a practical joke(lighting an M80 and tossing it beside my bed,after 4 M80s he gave up and put ice on my back) he said all i did was roll over and continue to snore.I actually woke up once to the EMS trying to put an IV in me because my mom thought i was dead, she couldn't get me to wake up for school.


----------



## BryceM (Nov 6, 2005)

Maybe you are dead.....


----------



## OhioPlantedtankguy (Aug 7, 2008)

BryceM said:


> Maybe you are dead.....


nah i just sleep like it lol


----------

