Co2 In Confined Spaces

[chovain]

I had a doctor-friend around at my place recently, and he raised a good question about my keg set-up. My 9kg CO2 tank sits next to my fridge, which is in my laundry. My laundry has no windows. What happens if I get a leak?

I was able to temporarily convince myself that it wasn't an issue:
1. A rapid leak (like a burst valve) will be audible.
2. A slow leak will settle on the ground over time. A 9kg tank holds less than 5m of gas at atmospheric temp/pres, so it would either just form a nice thin layer on the ground in my apartment, or mix in with the air, leading to a relatively small increase in CO2 levels.

The problem is, I keep thinking of scenarios that make me a little concerned: Come home just after the cylinder has blown with the laundry door open. Go to do something in the laundry, and if you don't know why you've started hyperventilating, you'll probably suffocate.

I know pubs and breweries tend to use alarms in areas involving CO2 storage or production. Do any home brewers out there take any precautions? Is there a cheap way of setting up a CO2 alarm other than getting a hamster? Am I just being paranoid?

 

[tangent]

Not too hard to have a slow leak that empties the entire bottle overnight. Your worries are worthy.

 

[ausdb]

I had a doctor-friend around at my place recently, and he raised a good question about my keg set-up. My 9kg CO2 tank sits next to my fridge, which is in my laundry. My laundry has no windows. What happens if I get a leak?

I was able to temporarily convince myself that it wasn't an issue:
1. A rapid leak (like a burst valve) will be audible.
2. A slow leak will settle on the ground over time. A 9kg tank holds less than 5m of gas at atmospheric temp/pres, so it would either just form a nice thin layer on the ground in my apartment, or mix in with the air, leading to a relatively small increase in CO2 levels.

The problem is, I keep thinking of scenarios that make me a little concerned: Come home just after the cylinder has blown with the laundry door open. Go to do something in the laundry, and if you don't know why you've started hyperventilating, you'll probably suffocate.

I know pubs and breweries tend to use alarms in areas involving CO2 storage or production. Do any home brewers out there take any precautions? Is there a cheap way of setting up a CO2 alarm other than getting a hamster? Am I just being paranoid?

It depends on the volume of the room to the volume of gas that could be released and whether it can reach a lethal / critical concentration. There is an Australian standard covering this as it applies with refrigerants and other gases, I will try and look up the number if I can. In most situations where it is a concern then things like door relief openings or adjoining spaces that are not sealed off can be used to increase the volume of the room in concern to the amount of gas that could be released.

Is your toilet adjacent to your laundry? if so then it probably has a vented window so make sure you leave the toiler door open whilst you are out or undercut the door.

 

[newguy]

This is actually something that I've thought of before, but I could never come up with an effective way to tell if the tank was leaking/empty. But (funny enough) as I was typing that first line I thought about using a digital scale to weigh the tank. An empty tank is much lighter than a full one. It would be easy enough to program a microcontroller to set off an alarm if the weight of the tank changed by x% in y hours/minutes. Failing that, hook up a big LED display for the weight. A quick eyeballing of the value will tell you whether the tank leaked and you can scram.

 

[sathid]

I've been thinking about this. In WA (don't know about the rest of the country) if you have natural gas bayonets, then you must also have a vent in the wall in case of leaks. This vent in my house is about 10cm above the ground, and is in the same room as the bayonet. Perhaps something like this would be suitable?

Now I just have to persuade SWMBO to let me keep the kegerator in the loungeroom.

 

[Cortez The Killer]

Anyone know of reported instances of this happening?

Cheers

 

[Fatgodzilla]

Anyone know of reported instances of this happening?

Cheers

Have you noticed since the boom in home brewing and the significant increase in home kegging levels that the CO2 levels in the world has been rising ? Are leaking beer gas bottles the true and hidden cause of increased greenhouse gas and global warming.

Save the planet, bottle your beer !

 

[the_fuzz]

I'm currently doing some stuff at work at the moment with Co2 alarms

You can get them and they are just like smoke alarms - pop one in the laundry and you do not have to worry again

In the states, these alarms are actually being standard due to central heating etc

 

[tangent]

Anyone know of reported instances of this happening?

Plenty of industrial deaths Wineries are pretty hardcore about the OH&S concerns of CO2 in confined spaces.
So far, none of the homebrewers that have died from asphyxiation have posted about it on AHB.

 

[sinkas]

.
2. A slow leak will settle on the ground over time. A 9kg tank holds less than 5m of gas at atmospheric temp/pres, so it would either just form a nice thin layer on the ground in my apartment, or mix in with the air, leading to a relatively small increase in CO2 levels.

Dont worry about it.

 

[KGB]

I wouldn't worry about it either. I assume your laundry is on the same level as the rest of the house? As soon as you open the door to get in there it will mix the CO2 to a "less lethal" concentration and you have to try pretty hard to die from it. If your beer and gas etc were in a dug out basement where the heavier-than-air CO2 could build up over time with no real means of escaping THEN it may be a valid concern.

 

[NRB]

A 9kg tank holds less than 5m of gas at atmospheric temp/pres

Where did you get that information? I would've predicted a greater volume of gas was contained in the bottle. I had no idea there was so little in them!

 

[BenH]

Where did you get that information? I would've predicted a greater volume of gas was contained in the bottle. I had no idea there was so little in them!

Following info from http://www.icbe.com/carbondatabase/CO2volumecalculation.asp

Volume calculation of one ton CO2
One ton = 1000kg
One cubic meter = 1000liters
One mole CO2 = 44.0g (CO2 = 12.0g + 32.0g = 44.0g)
One ton contains 22730 moles of CO2 (1,000,000g / 44.0g/mole)
One mole is 24.47L (Boyle's law at 25C and 1 atmosphere pressure)
Volume of one ton CO2 = 22730moles 24.47L/mole = 556200L = 556.2m

=> One ton of CO2 occupies 556.2m of volume.

That is, 1kg of CO2 occupies 0.57 cubic metres at atmospheric pressure.


(I'm not 100% sure of the accuracy of the above calculations, but it does seem to line up with Mark's calc)

 

[Jazzafish]

Don't worry about it.

Sure the gas is compressed in the tank, but I doubt that there will be enough in it to fill your laundry enough to purge out any oxygen and cause harm.
Also, your body's reflex to CO2 is pretty amazing. It would be an extreeme circumstance that you get yourself into danger on the home brew scale.

 

[poppa joe]

CO2 ....REPLACES>>>OXYGEN......
SNIFF IT >>>>TA TA....
PJ

 

[sqyre]

I would be worried...
i believe co2 is heavier than air? so it will sit in the lowest parts and not dilute?... and how high is your bed off the ground?
How high is your kids bed for that matter? or your pets...?

Not much different from dying in your sleep from smoke inhalation than co2 inhalation...

Be afraid.. very afraid... :angry:

Sqyre...

 

[chovain]

Following info from http://www.icbe.com/carbondatabase/CO2volumecalculation.asp

Volume calculation of one ton CO2
One ton = 1000kg
One cubic meter = 1000liters
One mole CO2 = 44.0g (CO2 = 12.0g + 32.0g = 44.0g)
One ton contains 22730 moles of CO2 (1,000,000g / 44.0g/mole)
One mole is 24.47L (Boyle's law at 25C and 1 atmosphere pressure)
Volume of one ton CO2 = 22730moles 24.47L/mole = 556200L = 556.2m

=> One ton of CO2 occupies 556.2m of volume.

That is, 1kg of CO2 occupies 0.57 cubic metres at atmospheric pressure.
(I'm not 100% sure of the accuracy of the above calculations, but it does seem to line up with Mark's calc)

I went for a much simpler approach. Wikipedia says that CO2's density at STP is 1.98 kg/m as a gas.

It's nice to see that it's reasonably accurate though.

NRB: it's actually a lot of volume. Just think about how many kegs you can fill with 4500L of gas at standard pressure!

 

[chovain]

I would be worried...
i believe co2 is heavier than air? so it will sit in the lowest parts and not dilute?... and how high is your bed off the ground?

It is heavier than air, but it's surprising how little 4.5 m will get you. If you take the area of my apartment that is closer to the laundry than my bed, you'll get a nice 10cm layer. Don't have any pets or kids :beerbang:

I also think it's more complicated than just settling out, otherwise there'd be no CO2 in the air we breathe.

 

[newguy]

I'm currently doing some stuff at work at the moment with Co2 alarms

You can get them and they are just like smoke alarms - pop one in the laundry and you do not have to worry again

In the states, these alarms are actually being standard due to central heating etc

:huh: Are you thinking of carbon monoxide alarms? They're not required by any building codes here, but they're a very good idea. At least once every winter there will be reports of a family found dead of carbon monoxide poisoning. Usually either the furnace has developed a leak or the chimney has collapsed. Or sometimes someone has either been gassed in their RV or their home because of a propane heater or propane BBQ.

I have a CO alarm. I've actually never heard of CO2 alarms. Could you post a link to one?

 

[mobrien]

I think a few people are missing a really important point here - Sure a 9kg bottle of liquid CO2 only makes 5 cubic metres of gas, but that is 100% pure gas. Sure CO2 does settle (its heavier than air) but that is only in a still environment - no such thing in a house, so mixing occurs.

Some levels of CO2 you should worry about:

1% (10,000 ppm) causes drowsiness with continuous exposure
2% is the normal threshold people can start to detect
3% normal breathing rate doubles (x2)
5% normal breathing rate quadruples (x4)
Levels above 5% are considered toxic

7-10% will cause unconsciousness in a few minutes (2-10mins according to the individual).

Continuous exposure levels limits are well below 1% - the US EPA recommend 0.1% (1000ppm) - for levels above this ventilation is required, other countries go as high as 5000ppm or 0.5%.

The normal concentration of CO2 in the atmosphere is 0.03%

So to put that into perspective, lets say we have a room 3m x 3m x 3m (thats bigger than the average laundry!). That gives us a volume of 27 cubic metres.

As a gas CO2 has a density of 1.87kg per cubic metre.

If the full 9kg cylinder emptied, AND there was no mixing in the room, this would give 4.8 cubic metres of gas over the floor layer - or a layer around 0.53m high.

However, if the air in the room mixes, it will give an overall concentration of 0.33kg per cubic metre or around 18% CO2 - thats nearly 4 times the toxic exposure level, and twice the level required to become unconscious.

From this we can scale back - loose half the tank, your at 9% CO2 in thee mixed room. Loose a quarter, you are at 4.5% CO2 in the mixed room.

Now start thinking about slow leaks.

Its not as simple as it first seems! Install ventilation in rooms with CO2, or get a CO2 alarm. And turn the gas off when you aren't using it!

M

Some web links if you don't believe me:

http://encyclopedia.airliquide.com/sds/en/018A_AL_EN.pdf
http://encyclopedia.airliquide.com/Encyclopedia.asp?GasID=26
http://www.inspect-ny.com/hazmat/CO2gashaz.htm

http://www.gasalarm.com.au/gasalarm/applic...erAlarm-CO2.pdf