OT. Runny dry ice...

[Jim K...]

Except the word "liquid" does not appear in the page you link to.... hence my question....

[Jim K...]

How would you have written it then?

[Tim+]

Reporters once again demonstrating their knowledge of basic science.

?An emergency incident at Glasgow Airport was caused by a leak from a package containing glass tubes of vaccine in the cargo hold of a plane. An exclusion zone was placed around the aircraft after concerns were raised about the leaking package onboard KLM flight KL1473 from Amsterdam. The airline said the leak affected dry ice packed to cool the package and the tubes of vaccine remained intact.?

Tim

[FMurtz]

You can get pelletized dry ice which you can pour through a funnel. I use it to fill co2 bottles.

[newshound]

If there was an insulation problem then evaporated dry ice could have set off a gas detector in the hold. I don't know how much dry ice is used in such packages (not a lot, I suspect) but I can see how there could have been a theoretical risk of asphyxiation. Alternatively, if the sign was the classic theatrical "smoke" from dry ice in water (could water have leaked into the packaging?) the cautious thing to do would be to treat it as a possible fire in the first case.

[Tim+]

Have you seen dry ice melt before?

Tim

[Tim+]

According to the Times staff were alerted by liquid leaking from a piece of luggage and that glass tubes were surrounded by melting dry ice...

Tim

[harry]

Dry ice normally sublimes.

[Martin Brown]

Which once the seal is broken very quickly becomes itself surrounded by water ice and water condensed out of the air. The operatives presumably saw the liquid water escaping and assumed that the vaccine was leaking (a not unreasonable precaution under the circumstances).

Dry ice sublimes but the other things it makes cold can end up becoming saturated with water and ice condensed out of the air.

[NY]

I can understand the word "melt" being used in connection with dry ice because most other frozen objects go through liquid phase before turning to gas - and "melt" is far more widely used in common vocabulary than the more obscure word "sublime".

If pools of liquid were seen, that does indeed sound like water from the atmosphere which has condensed onto the dry ice or the objects that it is cooling, and is then melting as the objects warm up to ambient temperature.

Are there any conditions in which CO2 *does* assume a liquid phase? Does it require much higher or lower pressure than 1 bar (atmospheric pressure)? Ah, Wikipedia to the rescue

- the triple point of CO2 (beyond which all three phases can exist) is 5.2 bar. So presumably CO2 cylinders could contain some liquid as well as gas, depending on what the typical pressure in a CO2 cylinder is.

[Andy Burns]

[PeterC]

Yes - it's sublime!

[Brian Gaff]

It normally just gives of co2 steam, which no doubt is illegal these days! Is it not what they use for smoke in stage effects? Brian

[Brian Gaff]

Dry ice is a silly name anyhow. After all carbon dioxide frozen cannot exist as a liquid at our air pressure anyhow. Brian

[harry]

Fire extinguishers.

[harry]

55 bar at room temperatures.

[Dave Plowman (News)]

Certainly when you use dry ice in a studio to give that fog across the floor effect, the floor gets slippery. With what I assumed was water.

[Richard]

ridiculous

[FMurtz]

When I fill my CO2 bottle with the same amount of dry ice by weight (as the original contents)and screw the valve back in, I leave it overnight and it turns back into liquid, it is much cheaper than conventional rental plus contents.(about $5.00 AU per kilo)You can fill your sodastream bottles the same way for a fraction of the exchange rate at the supermarket.

[newshound]

Yes but it wouldn't be sealed, otherwise the container would overpressurise and fail. And the net flow of carbon dioxide from the loose lid would stop air bringing water vapour in with it. But I agree, normal water condensation on a cold surface might be mistaken for leaking vaccine.