How much damage would liquid nitrogen (or other gases in liquid form do)?


General Discussion


I'm thinking like lava only cold instead of fire damage.


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Not really. I mean, liquid nitrogen won't do you any good, but its not going to compare at all with lava.

In both cases, the amount of damage correlates roughly with the energy differential between the unfortunate human being and the lava or liquid nitrogen. Exposure causes damage because either an excessive amount of energy is flowing into the unfortunate ( lava ), or flowing out ( liquid nitrogen ). The bigger the flow, the more the damage, and the bigger the energy differential, the bigger the flow.

Why does this matter? Because the amount of energy stored in "hot" matter is a *lot* greater than the amount of lack-of-energy "stored" in "cold" matter. Lava has a temperature ranging from 700 to 1200 Celsius, meaning a minimum 600 degrees Celsius over the boiling point of water. Meanwhile, liquid nitrogen is only -196 Celsius, meaning its only 196 degrees Celsius colder than the freezing point of water. What's more, there is no upper limit on how hot things can get ( though eventually you don't have lava anymore, you have other things ). . . while the absolute coldest anything can get ever is -273 Celsius. . . which is *still* less than half the heat differential between boiling water and the coldest of lavas.

So, no, liquid nitrogen isn't anywhere near as bad as lava.

( There are some other additional complications, having to do with the heat of fusion/vaporzation, but they don't fundamentally change the situation. )


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On the other hand, the comic book style vats they probably use to make cold guns & grenades probably operate on quantum magical BS and do just as much as lava except it's cold damage.


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I'm agreeing with Lava only cold damage. No sense in re-inventing the horse here. Same as liquid Oxygen, or liquid helium.


Actually, liquid helium should be a lot worse. Even though the temperature isn't THAT much lower, and it is a LOT better conductor of heat, which will make the heat flow much faster. (It is also enough colder to freeze air, in situations where that would make a difference.) Probably still not as bad as lava (unless the lava formed an insulating solid layer on itself), but still a lot worse than liquid nitrogen/oxygen.

Maybe liquid helium (and hydrogen) should probably count as the mundane equivalent of supernatural cold (including overcoming ordinary Cold Resistance). Although last I checked, lava doesn't count as the mundane equivalent of supernatural fire (but Sun-class and greater stellar temperatures definitely should).

Grand Lodge

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Yeah I disagree with making liquid nitrogen equivalent in damage to lava. Maybe half as bad at worst. Supernaturally chilled nitrogen might be equivalent, buuuuuuuut, the bog stabdard liquid nitrogen shouldn’t be that degree of harmful. Keep in mind coming within 3 feet of lava is enough to cause things to bust into flame. You need to immerse a surface to cause harm, so making these two substance equivalent seems inappropriate given their vast differences in scale, as Metaphysician said


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Throw a water balloon into lava and it explodes. What is most of the body made of, for most living creatures, again?


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....feelings?


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Lol.

(The answer is water.)


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Nope, I have to go with Pantshandshake there. ;)


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Personally, I lean towards eliminating the distinction between "normal heat/cold" and "supernatural heat/cold", at least in terms of it referring to intensity. Heat and cold are heat and cold, with their damage determined purely by how hot/cold they are. A magical source should only matter insofar as you are dealing with something like an incorporeal entity. . . and just because the heat or cold is really intense, doesn't cause it to "magically" become magic.


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It won't do any damage to you. In RL I've been splashed with liquid nitrogen. It boiled away too fast for it to do anything except feel cold. It hit my skin and clothes (cotton shirt, denim pants and sneakers) and yeah it chilled for a second then back to normal.

The only time it does damage is when it lingers on one spot. If you cupped your hands and held some, or if you were wearing sandals and it was trapped between your foot and sandal. And even then you'd only have skin deep frostbite.

You'd have to hold a body part under significant amount of nitrogen for it to do enough damage. A few minutes to freeze a hand.

I don't have any experience with other liquid gases.

Sovereign Court

On the other hand, drink some liquid nitrogen and you are dead. Even a mouthful.


Sailor Palidor wrote:

It won't do any damage to you. In RL I've been splashed with liquid nitrogen. It boiled away too fast for it to do anything except feel cold. It hit my skin and clothes (cotton shirt, denim pants and sneakers) and yeah it chilled for a second then back to normal.

The only time it does damage is when it lingers on one spot. If you cupped your hands and held some, or if you were wearing sandals and it was trapped between your foot and sandal. And even then you'd only have skin deep frostbite.

You'd have to hold a body part under significant amount of nitrogen for it to do enough damage. A few minutes to freeze a hand.

I don't have any experience with other liquid gases.

Extremely brief exposure like a splash won't do anything bad if the liquid nitrogen is right at its boiling point, but exposure in the seconds will cause frostbite. Liquid nitrogen significantly below its boiling point will be much worse -- this stuff is used to freeze things that won't freeze fast enough in liquid nitrogen at its boiling point, which forms a layer of gaseous nitrogen that partially insulates the object that it is in contact with. Likewise with touching liquid propane that has been chilled almost down to liquid nitrogen temperature (propane has a LONG liquid range for a cryogenic liquid, and its freezing point is just above the boiling point of nitrogen). To a lesser (but still highly dangerous) extent, likewise for touching metal that has been cooled down to liquid nitrogen temperature.


Also, isn't the dangerous part of liquid nitrogen the risk of suffocation?
As in, if there's enough of it in an enclosed space, it will boil off quickly and displace what oxygen is in the room?


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Ellias Aubec wrote:
On the other hand, drink some liquid nitrogen and you are dead. Even a mouthful.

Don't bars and clubs make use of the stuff to make their drinks fancier?


I wouldn't be surprised, it is used to make ice cream in under 2 minutes.


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However (getting back to the main point of this) if you are trying to have say a big old pool of Liquid N2 that someone falls into, Lava damage. If you're looking at what happens if you throw a beaker of it on someone, alchemist fire (only cold).

And yes some clubs us Liquid N2 for drinks, but it is entirely gone before you even get the drink, you just get the cloud effect.


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Ellias Aubec wrote:
On the other hand, drink some liquid nitrogen and you are dead. Even a mouthful.

Its not guaranteed death, people have survived doing that. You'd better high tail it to a hospital, though, as between the cold and the suddenly expanding quantity of gas, your innards are going to take a drubbing.

Dark Archive

Garretmander wrote:

Also, isn't the dangerous part of liquid nitrogen the risk of suffocation?

As in, if there's enough of it in an enclosed space, it will boil off quickly and displace what oxygen is in the room?

Not really. After all, most of what you breathe is already nitrogen. Suffocation is more likely to occur from gases like CO that interfere with the body's ability to absorb oxygen. The only time breathing nitrogen gets dangerous is when it is done in high pressure situations where it actually gets into the blood stream, or when depressurizing from such a state too rapidly, where it can then form bubbles in the blood (nitrogen narcosis/bends).


World of Dim Light wrote:
Garretmander wrote:

Also, isn't the dangerous part of liquid nitrogen the risk of suffocation?

As in, if there's enough of it in an enclosed space, it will boil off quickly and displace what oxygen is in the room?
Not really. After all, most of what you breathe is already nitrogen. Suffocation is more likely to occur from gases like CO that interfere with the body's ability to absorb oxygen. The only time breathing nitrogen gets dangerous is when it is done in high pressure situations where it actually gets into the blood stream, or when depressurizing from such a state too rapidly, where it can then form bubbles in the blood (nitrogen narcosis/bends).

No, I distinctly remember this in chem lab safety... nine years ago? Though, that might have been because they had a massive many dozens of gallons tank outside, and if that was leaking into a room that was what caused problems.


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World of Dim Light wrote:
Garretmander wrote:

Also, isn't the dangerous part of liquid nitrogen the risk of suffocation?

As in, if there's enough of it in an enclosed space, it will boil off quickly and displace what oxygen is in the room?
Not really. After all, most of what you breathe is already nitrogen. Suffocation is more likely to occur from gases like CO that interfere with the body's ability to absorb oxygen. The only time breathing nitrogen gets dangerous is when it is done in high pressure situations where it actually gets into the blood stream, or when depressurizing from such a state too rapidly, where it can then form bubbles in the blood (nitrogen narcosis/bends).

Liquid nitrogen -- or for that matter dry ice or liquid carbon dioxide(*) -- evaporating can definitely displace the oxygen in a room down to a dangerously low level if it is occurring faster than what the air conditioning can change out. Where I work (research lab in a hospital) the safety people make a strong point to warn everyone about this, with the additional note that cold rooms are NOT the same as air conditioning, and won't put fresh air back in (it diffuses in very slowly, mostly when somebody opens the door), meaning that even a slow boiloff can push the oxygen levels down dangerously low. The dangerous part isn't breathing the nitrogen (since like you said, the air is already 79% nitrogen) -- it is breathing air that doesn't have enough oxygen (but in the case of carbon dioxide, from dry ice or otherwise, high concentrations of carbon dioxide are toxic in their own right even if you still have enough oxygen).

(*)Yes, carbon dioxide does exist as a liquid if you compress it to at least 5.10 atmospheres = 517 kPa = 74.9 psi absolute, and I have seen tanks of liquid carbon dioxide, used to supply carbon dioxide gas systems -- apparently, for large systems that are continuously using carbon dioxide, it is more economical than compressed carbon dioxide or dry ice.


It's worth remembering that even once it's evapourated, the nitrogen is probably still a lot colder than the surrounding air, and cold air sinks. It diffuses pretty slowly too, so what you end up with is a layer of nitrogen rich / oxygen poor air near the floor. If you breathe a couple of lungfuls of air without enough oxygen, you can pass out, at which point you fall to the floor and continue not breathing oxygen.

If my starfinder game had a big open topped tank of liquid N2 in it, I think I'd at least be subjecting anyone near it (but not above it) to altitude sickness if not suffocation.


Well when you think about it lava should also pose a suffocation risk when you're near due to all the smoke and hot air (which would poison you as well as probably burn your lungs) but lava doesn't do that in Pathfinder/Starfinder. Why is this?


^Hot air tends to go up, so if you are off to the side of the lava and not so near as to get an excessive amount of heat and not downwind of it, you will probably be okay. On the other hand, being over it (like in those movie fights on bridges over lava) would be bad. Now, if the gases from lava cool down before they mix too much with the atmosphere (such as if they diffuse up through rock or water), then they will tend to sink, because they contain considerable carbon dioxide, and then they can suffocate you.

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