dry ice transit; where does the co2 go?

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liveaboard
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dry ice transit; where does the co2 go?

Post by liveaboard »

I've actually thought about this before, but with it all in the news...

What happens to the co gas emitted by dry ice as it evaporates in an aircraft or even a closed van?
I suppose there are safety systems to prevent people from suffocating, fairly easy so long as drivers / pilots / freight handlers are aware.

I actually had to think about this once, and quickly.
I had a fire in the engine room of my boat, and put it out with a co2 extinguisher. As I took the thing off the wall, it occurred to me that as soon as I pulled the handle in a closed room, oxygen could become scarce.

CO2 extinguishers are no longer permitted on boats in the Netherlands. Worked well for me though.
curtis cutter
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Re: dry ice transit; where does the co2 go?

Post by curtis cutter »

Very interesting observation. It certainly is worthy of consideration. Those heavier than air gasses as well as lighter than air gasses can create hazardous conditions that are not visible to people.

Halon was another extinguishing agent that was used extensively in computer rooms and aircraft in the 60's and 70's. It extinguished by interrupting the reaction of fire and not allowing further combustion. One of the positive aspects was that it was not toxic to humans but in large quantities could displace oxygen.

Speaking of gasses, propane and natural gas create different issues in buildings with natural gas frequently be the more difficult to deal with. Propane, being heavier than air, can usually be easily removed from an above ground structure simply by opening doors and windows. Natural gas, being lighter than air, can be difficult to remove as it rises in the structure. Issues are created with commercial structures with natural gas when structures have 20 plus foot ceilings and 7 foot above grade doors and windows.
Gregg
Just let go of it, it will eventually unplug itself.
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liveaboard
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Re: dry ice transit; where does the co2 go?

Post by liveaboard »

My houseboats in Amsterdam have natural gas, connected to the city network.
For a long time, the gas company refused to connect the 2,000 houseboats in the city, citing safety concerns.
The fire department blew up that argument, pointing out [as you did] that natural gas is far less dangerous than propane in a space with a sealed bottom.
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Steggy
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Re: dry ice transit; where does the co2 go?

Post by Steggy »

liveaboard wrote: Mon Dec 14, 2020 3:40 amThe fire department blew up that argument...
Interesting choice of words. :D
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SteveM
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Re: dry ice transit; where does the co2 go?

Post by SteveM »

I have wondered about the CO2 issue as well, thinking that I would not want to transport something being kept cool with dry ice in a confined space.

You have to wonder about Omaha Steaks being transported in mail trucks.

Learned some interesting stuff in some fire training:

When the space is filled with flammable gas above some concentration, there can be no combustion because there is not enough oxygen.

When the gas is below some other concentration, there is no combustion because there is not enough gas.

Between those two levels is the danger zone.

When you are ventilating a space full of flammable gas, you have to go from a "safe" situation, thru the danger zone to get to the real safe situation.

Steve
Russ Hanscom
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Re: dry ice transit; where does the co2 go?

Post by Russ Hanscom »

If you figure the rate of sublimation (solid to gas conversion), the rate of gas production is probably small, and a space with any ventilation is probably safe.
curtis cutter
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Re: dry ice transit; where does the co2 go?

Post by curtis cutter »

SteveM wrote: Mon Dec 14, 2020 4:02 pm I have wondered about the CO2 issue as well, thinking that I would not want to transport something being kept cool with dry ice in a confined space.

You have to wonder about Omaha Steaks being transported in mail trucks.

Learned some interesting stuff in some fire training:

When the space is filled with flammable gas above some concentration, there can be no combustion because there is not enough oxygen.

When the gas is below some other concentration, there is no combustion because there is not enough gas.

Between those two levels is the danger zone.

When you are ventilating a space full of flammable gas, you have to go from a "safe" situation, thru the danger zone to get to the real safe situation.

Steve
There are upper explosive limits and lower explosive limits of fuel vapors. It is surprising how some gasses need a very narrow percentage concentrations of gas to burn and others have a very wide range. Gasoline is actually very narrow compared to acetylene.

https://www.engineeringtoolbox.com/expl ... d_423.html

Many years ago I was driving a fire engine to a "smell of natural gas in a neighborhood". A very common call. While driving through the area I approached a bridge over a fast flowing river. Just as I entered the bridge water started splashing onto the bridge deck and everything in the distance became a blurry wave due to the gas flowing from a 20" high pressure line that finally went from a small leak to a wide open pipe. I quickly pulled the engine shutdown lever and told the crew to touch nothing. I rolled through on the truck momentum. Once I was a couple hundred feet down the road I restarted the engine.

Those who know natural gas know that it actually is an odorless gas that has mercaptan added to have a smell to alert people to a leak. The mercaptan is introduced into the line at various points in the system. We had an incredible number of 911 calls for a smell of gas one day and the odd thing was you could follow the calls as the neighboring town was sent out then we were sent out. When you finish delivering mercaptan to a distribution site, you really should turn the valve completely off while you go to the next delivery site. One pound of the mercaptan will treat about 10,000 gallons of liquid gas so even a few drops can be an issue.
Gregg
Just let go of it, it will eventually unplug itself.
Russ Hanscom
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Re: dry ice transit; where does the co2 go?

Post by Russ Hanscom »

Quite so. Long ago, we had natural gas processing plant that was normally down wind from a city. A couple of employees assigned to general cleanup decided that the best way to get rid of an almost empty cylinder of mercaptan was to vent it; unfortunately on a rare day when the wind was towards town. The result that a Costco and several other big box stores were evacuated due to a probable gas leak. The fire dept visited our facility but the persons they encountered were innocent and not aware of a problem. Management eventually figured out the story and the couple involved got some unpaid vacation for their effort.
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Re: dry ice transit; where does the co2 go?

Post by liveaboard »

I've repurposed some old propane cylinders, some dregs of that stuff is always in the bottom.
Downwind is where it goes; but of course, my downwind is someone's upwind.
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Re: dry ice transit; where does the co2 go?

Post by Steggy »

liveaboard wrote: Tue Dec 15, 2020 1:10 pm I've repurposed some old propane cylinders, some dregs of that stuff is always in the bottom.
Downwind is where it goes; but of course, my downwind is someone's upwind.
As long as you don't break wind when you're upwind and I'm downwind... :D
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Music isn’t at all difficult.  All you gotta do is play the right notes at the right time!  :D
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liveaboard
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Re: dry ice transit; where does the co2 go?

Post by liveaboard »

I'm always ready to help out my neighbors; loan a tool, pull something out with my tractor, small things.

So when god-awful noises and odors come from my place, they forgive me.
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