6 ms·

Can you please elaborate why gloves are bad ? I've never handled liquid nitrogen, but everytime I've seen someone handle it they wore gloves like these: https

Can you please elaborate why gloves are bad ? I've never handled liquid nitrogen, but everytime I've seen someone handle it they wore gloves like these: https://www.2spi.com/category/cryo-gloves/ https://www.2spi.com/category/cryo-gloves/

boobsbr 8y ago
Perhaps because of the Leidenfrost effect? LN would evaporate before, or very briefly during, contact with skin, creating a cushion of air under the droplet, making it just roll away and avoid freezing of the skin. Maythe the LN would "stick" to the gloves, freeze them, and then freeze the skin?
- thunfischbrot 8y ago
  Proper long cryo gloves are fine. It's what you are supposed to use. The issue you are mitigating with the gloves is mostly that you may inadvertently touch surfaces which are extremely cold, freezing your skin itself or freezing it to the surface. Due to the Leidenfrost effect one is rather safe from touching LN directly unless it is for more than a couple of seconds.
friendzis 8y ago
Gloves are not inherently bad, but the risks they do not protect from are not obvious. For the sake of this comment room temperature is 0 heat, cold is negative heat (offset scale). Gloves are not a perfect insulator, therefore they absorb heat and cold. It takes time for the cold to permeate the gloves - i.e. you observe significant temperature gradient over thickness of the glove. By the time your hand feels the cold, the whole width of the glove is bloody cold. In order to remove the cold from the glove you need to heat it. The only heat source is your hand inside of the glove, therefore the heat is taken from your hand. You need as much heat from your hand as much cold you have taken from LN to bring the gloves to 0. Unless you remove the gloves when the cold starts to permeate - hello frostbite. While Leidenfrost effect allows one to splash LN on their hands without any or at least significant damage, gloves simply allow more splashes, not full immersion. Handling LN with gloves is a delaying technique, gloves do not magically protect from cold.
- brusch64 8y ago
  Thank you - this makes perfect sense !
- tjoff 8y ago
  I don't doubt that you are right. But that whole description could, to my inexperienced ears, just as well be an argument as to why you really really should be wearing gloves at all times. If the gloves slow down the process enough so that when you feel cold you have time to put down the container and remove the gloves (less than five seconds?). I mean, to me I'd imagine that is the sole purpose to wear them in the first place? It would, I imagine, also help from panic. If you notice that you got LN on your gloves there is less panic than getting it on your skin - less chance of a reflex reaction that just makes things worse.
  - friendzis 8y ago
    You are correct, one of the main purposes for wearing gloves when handling really cold/hot materials is to provide that time cushion to handle the thing or contain accident safely. The question was why gloves are not necessarily a good preventative measure. For example if you are arc welding and some nasty blob of molten metal drops on your hand, gloves will provide "heat through" time cushion to remove the gloves more or less safely (easily removable layer also helps avoid hot/cold blob sticking to your body), but keeping the gloves on will most likely still result in a burn. There is a hidden danger with cold that cold does not radiate like heat and we have much less intuitive understanding of how cold affects the skin. Sometimes people get frostbitten during winter activities without them noticing that something was too cold for too long.
  - jonhendry18 8y ago
    What if your hands have sweated, and your skin freezes to the glove material? Removing the gloves might be difficult to do quickly.
- Retric 8y ago
  This depends on how insulated they are. You could make gloves that allowed you to stick your hand in -200C all day long. It's the same reason winter coats work, slow heat loss below the body's heat protection and you get unlimited duration. The problem is most gloves are designed for vastly warmer temperatures and you don't notice frostbite if your hand cools down slowly.
tptacek 8y ago
In addition to my sibling comment, the practical risk is that instead of splashes skittering across your skin (probably harmlessly), gloves present an opportunity for LN to get trapped up against your skin, where it will most certainly burn you.

boobsbr 8y ago

Perhaps because of the Leidenfrost effect? LN would evaporate before, or very briefly during, contact with skin, creating a cushion of air under the droplet, making it just roll away and avoid freezing of the skin. Maythe the LN would "stick" to the gloves, freeze them, and then freeze the skin?

thunfischbrot 8y ago
Proper long cryo gloves are fine. It's what you are supposed to use. The issue you are mitigating with the gloves is mostly that you may inadvertently touch surfaces which are extremely cold, freezing your skin itself or freezing it to the surface. Due to the Leidenfrost effect one is rather safe from touching LN directly unless it is for more than a couple of seconds.

friendzis 8y ago

Gloves are not inherently bad, but the risks they do not protect from are not obvious. For the sake of this comment room temperature is 0 heat, cold is negative heat (offset scale). Gloves are not a perfect insulator, therefore they absorb heat and cold. It takes time for the cold to permeate the gloves - i.e. you observe significant temperature gradient over thickness of the glove. By the time your hand feels the cold, the whole width of the glove is bloody cold. In order to remove the cold from the glove you need to heat it. The only heat source is your hand inside of the glove, therefore the heat is taken from your hand. You need as much heat from your hand as much cold you have taken from LN to bring the gloves to 0. Unless you remove the gloves when the cold starts to permeate - hello frostbite. While Leidenfrost effect allows one to splash LN on their hands without any or at least significant damage, gloves simply allow more splashes, not full immersion. Handling LN with gloves is a delaying technique, gloves do not magically protect from cold.

brusch64 8y ago
Thank you - this makes perfect sense !
tjoff 8y ago
I don't doubt that you are right. But that whole description could, to my inexperienced ears, just as well be an argument as to why you really really should be wearing gloves at all times. If the gloves slow down the process enough so that when you feel cold you have time to put down the container and remove the gloves (less than five seconds?). I mean, to me I'd imagine that is the sole purpose to wear them in the first place? It would, I imagine, also help from panic. If you notice that you got LN on your gloves there is less panic than getting it on your skin - less chance of a reflex reaction that just makes things worse.
- friendzis 8y ago
  You are correct, one of the main purposes for wearing gloves when handling really cold/hot materials is to provide that time cushion to handle the thing or contain accident safely. The question was why gloves are not necessarily a good preventative measure. For example if you are arc welding and some nasty blob of molten metal drops on your hand, gloves will provide "heat through" time cushion to remove the gloves more or less safely (easily removable layer also helps avoid hot/cold blob sticking to your body), but keeping the gloves on will most likely still result in a burn. There is a hidden danger with cold that cold does not radiate like heat and we have much less intuitive understanding of how cold affects the skin. Sometimes people get frostbitten during winter activities without them noticing that something was too cold for too long.
- jonhendry18 8y ago
  What if your hands have sweated, and your skin freezes to the glove material? Removing the gloves might be difficult to do quickly.
Retric 8y ago
This depends on how insulated they are. You could make gloves that allowed you to stick your hand in -200C all day long. It's the same reason winter coats work, slow heat loss below the body's heat protection and you get unlimited duration. The problem is most gloves are designed for vastly warmer temperatures and you don't notice frostbite if your hand cools down slowly.

tptacek 8y ago

In addition to my sibling comment, the practical risk is that instead of splashes skittering across your skin (probably harmlessly), gloves present an opportunity for LN to get trapped up against your skin, where it will most certainly burn you.