storing Dry Ice

[the kid]

But if it is in a domestic freezer there kinda deep and bearing in mind that the dry ice decomposes, and stays at a low level, will this not mean that over time there be be a layer of deadly gas resting at the bottom of the freezer??

[bruce]

over time there be be a layer of deadly gas resting at the bottom of the freezer??

 

It's C02. It's not "deadly" as in poison. But as it displaces oxygen, it can suffocate.

 

Suppose the container was full of water - it would be equally "deadly" - in that if you stuck your head into it for a while, you wouldn't be able to breathe. The difference, of course, is that water is a little more obvious B-)

[Ynot]

one more question - the dry ice when melts bcomes gas, so dead freezer has a lid on not letting the gas relaease - build up of pressure and then discuss.......

Yes, there will be a build-up of gaseous CO2 in a chest freezer, and yes this most certainly a danger to anyone foolish enough to stick their head in the box! It wouldn't kill you by poisoning, as it's not that sort of gas, but you could suffocate if you breathed it too long, and certainly cause respiratory difficulties prior to that.

However, the sensible thing to do is to build up the bottom of the box with insulating material (polystyrene, newspapers etc) so that the ice blocks are near the top, with adequate room to insulate over it as well. This reduces the risk of having to delve too deep for it.

If you have a sufficient quantity that means you're FILLING a freezer full of CO2 (unlikely except in big production shows) then obvious care must be taken - sensible to have TWO people fetch the ice blocks - one to retrieve, the other as a 'spotter' for safety. That's a little extreme, but it depends on the circumstances.

 

As for pressure, I've never experienced any build up of pressure in a dry ice container. In the past I've used a variety of storage mediums, including an old school dinners insulated container with a secure latch, and there's never been any issue with this. I don't beilieve that CO2 is that volatile that it can present such a danger.

Of course, if anyone has other experience....

 

TD

[tompw]

To summarise: use a dead freezer, and pack out space not taken up by the dry ice with insulating material. Using a live freezer will (almost certainly) result in a dead compressor pump.

 

If you want to be certain to avoid pressure build-up, then drill just a small hole in the top or side of your dead freezer.

 

 

Important health point... you should *never* store dry ice in the same container/locality as food. The extra CO2 gas from the subliming dry ice will dramatucally promote the growth of aneraobic bacteria (which tend to be nasty to your digestion)... resulting in rather spoilt food. Yes, ice cream vans and the like use lumps of dry ice, but there is a barrier between the dry ice and the food.

 

On the other hand, nearby potted plants will be happy.

[Ynot]

Important health point... you should *never* store dry ice in the same container/locality as food. The extra CO2 gas from the subliming dry ice will dramatucally promote the growth of aneraobic bacteria (which tend to be nasty to your digestion)... resulting in rather spoilt food. Yes, ice cream vans and the like use lumps of dry ice, but there is a barrier between the dry ice and the food.

That's an interesting point which seems to contradict the hurricane emergency cooling theory..... B-)

[dbuckley]

Whereever you store your dry ice should be well ventilated sideways. If you put your freezer onstage then below stage will become full of CO2, as the CO2 being heavier than air falls, and if your under stage area is not well ventilated it could become a killing pit.

 

As to gas buildup in the freezer, it will escape, the only question is how spectacularly...

[Andrew C]

If you want to be certain to avoid pressure build-up, then drill just a small hole in the top or side of your dead freezer.

Don't. There is a good chance you will drill through a coolant pipe. Old freezers are full of ozone bggring chemicals that should be drained properly for the sake of the planet, never mind that some are carcinogens. As to speeding the spoiling of food, can you give any references? It seems counter intuitive to me.

[dbuckley]

As to speeding the spoiling of food, can you give any references? It seems counter intuitive to me.

Depends how you read it.

 

you should *never* store dry ice in the same container/locality as food.

Thats say to me "never store non-frozen food in the same area as you have dry ice producing CO2 gas".

 

The non-frozen food will be harbouring bugs which will be growing slowly at room temperature, and increased CO2 presence will accelerate the growth of anaerobic bateria, because they hate oxygen, and CO2 displaces oxygen. If the food were frozen then the same concerns may not apply.

 

David, whose first career was as a medical lab hospital technician, and has thus cultured his fair share of anaerobic bacteria, which are generally nastier than the aerobic varieties, and stink like hell......

[Ynot]

David, whose first career was as a medical lab hospital technician, and has thus cultured his fair share of anaerobic bacteria, which are generally nastier than the aerobic varieties, and stink like hell......

/Tongue in cheek/

Are the aerobic bacteria fitter than the non-aerobic ones, then.....?

/tongue outta cheek/

B-) :) :angry:

[robloxley]

Going back to the OP, have you thought about co2 cylinder based solutions, from a cost/ease/COSHH standpoint?

[Ynot]

Going back to the OP, have you thought about co2 cylinder based solutions, from a cost/ease/COSHH standpoint?

Think that was mentioned/discounted a while back....

[robloxley]

Going back to the OP, have you thought about co2 cylinder based solutions, from a cost/ease/COSHH standpoint?

Think that was mentioned/discounted a while back....

Must have missed that

[OB2]

well after all that, the director decided it would be too much hassle, too expensive for the sake of a 30 seconds effect, we are now using white clothes.............

not quite as exciting for me, but it does mean I get the evnings off now!

[Ynot]

well after all that, the director decided it would be too much hassle, too expensive for the sake of a 30 seconds effect, we are now using white clothes.............

Hmmm...

That to me sounds typical of an inexperienced director.

I always maintain that the best effects are used once, and don't last too long (depending on the effect).

Any more than is necessary and you lose that 'wow!' factor (if it's done properly)

 

TD

[Ekij]

CO2 wouldn't kill you by poisoning, as it's not that sort of gas, but you could suffocate if you breathed it too long, and certainly cause respiratory difficulties prior to that.

Actually CO2 is acidic, at about 5% CO2 the air becomes sufficiently acidic to muck up the acidity regulators in the blood stream and cause you problems, even when there is still plenty of O2 in the air for you to metabolise.

Thats why submarines (and space ships) have scrubbers to remove the CO2 (rather than just adding more O2 to the air, which would be a lot simpler).