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Is a CO2 fire extinguisher safe to use indoors to represent offensive magic or breath weapons in LARP?
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In short: my friend, who is also a LARP organizer, has come up with the idea of representing breath weapons and some kinds of offensive weapons (those that are represented by a "cone template" in many games) via a CO2 fire extinguisher.
CO2 is basically just compressed air. However, I have experience of using it for cleaning purposes, and I know that it becomes extremely cold. So, I cannot be sure about its safety.
So, is one safe to use indoors? If yes -- what safety measures do I need?
larp physical-safety
asked 23 hours ago
Baskakov_Dmitriy
4,05312069
 |Â
show 4 more comments
up vote
29
down vote
favorite
In short: my friend, who is also a LARP organizer, has come up with the idea of representing breath weapons and some kinds of offensive weapons (those that are represented by a "cone template" in many games) via a CO2 fire extinguisher.
CO2 is basically just compressed air. However, I have experience of using it for cleaning purposes, and I know that it becomes extremely cold. So, I cannot be sure about its safety.
So, is one safe to use indoors? If yes -- what safety measures do I need?
larp physical-safety
asked 23 hours ago
Baskakov_Dmitriy
4,05312069
69
CO2 is very much not "just compressed air".
– T.J.L.
23 hours ago
4
Are you doing this indoors or outdoors?
– thosphor
21 hours ago
8
CO2 isn't just an oxygen displacer, humans are also allergic to it. That "OMG must breathe" sensation you get when you are not breathing, is not a lack of oxygen... actually there's still plenty of oxygen. That feeling is caused by the buildup of CO2 in not particularly high concentrations. It serves as a substitute for an oxygen density detector, which would've been evolutionarily harder to evolve.
– Harper
17 hours ago
3
flashlights make a cone... use that
– RedOculus
16 hours ago
10
@Harper "Allergic" isn't really the right term - it's not an immune system response or anything, or even an evolved response. It's the buildup of carbonic acid, which forms when there's a bunch of CO2 dissolved in water.
– Delioth
15 hours ago
 |Â
show 4 more comments
up vote
29
down vote
favorite
up vote
29
down vote
favorite
In short: my friend, who is also a LARP organizer, has come up with the idea of representing breath weapons and some kinds of offensive weapons (those that are represented by a "cone template" in many games) via a CO2 fire extinguisher.
CO2 is basically just compressed air. However, I have experience of using it for cleaning purposes, and I know that it becomes extremely cold. So, I cannot be sure about its safety.
So, is one safe to use indoors? If yes -- what safety measures do I need?
larp physical-safety
asked 23 hours ago
Baskakov_Dmitriy
4,05312069
In short: my friend, who is also a LARP organizer, has come up with the idea of representing breath weapons and some kinds of offensive weapons (those that are represented by a "cone template" in many games) via a CO2 fire extinguisher.
CO2 is basically just compressed air. However, I have experience of using it for cleaning purposes, and I know that it becomes extremely cold. So, I cannot be sure about its safety.
So, is one safe to use indoors? If yes -- what safety measures do I need?
larp physical-safety
larp physical-safety
asked 23 hours ago
Baskakov_Dmitriy
4,05312069
asked 23 hours ago
Baskakov_Dmitriy
4,05312069
edited 22 mins ago
asked 23 hours ago
Baskakov_Dmitriy
4,05312069
asked 23 hours ago
Baskakov_Dmitriy
4,05312069
asked 23 hours ago
Baskakov_Dmitriy
4,05312069
4,05312069
69
CO2 is very much not "just compressed air".
– T.J.L.
23 hours ago
4
Are you doing this indoors or outdoors?
– thosphor
21 hours ago
8
CO2 isn't just an oxygen displacer, humans are also allergic to it. That "OMG must breathe" sensation you get when you are not breathing, is not a lack of oxygen... actually there's still plenty of oxygen. That feeling is caused by the buildup of CO2 in not particularly high concentrations. It serves as a substitute for an oxygen density detector, which would've been evolutionarily harder to evolve.
– Harper
17 hours ago
3
flashlights make a cone... use that
– RedOculus
16 hours ago
10
@Harper "Allergic" isn't really the right term - it's not an immune system response or anything, or even an evolved response. It's the buildup of carbonic acid, which forms when there's a bunch of CO2 dissolved in water.
– Delioth
15 hours ago
 |Â
show 4 more comments
69
CO2 is very much not "just compressed air".
– T.J.L.
23 hours ago
4
Are you doing this indoors or outdoors?
– thosphor
21 hours ago
8
CO2 isn't just an oxygen displacer, humans are also allergic to it. That "OMG must breathe" sensation you get when you are not breathing, is not a lack of oxygen... actually there's still plenty of oxygen. That feeling is caused by the buildup of CO2 in not particularly high concentrations. It serves as a substitute for an oxygen density detector, which would've been evolutionarily harder to evolve.
– Harper
17 hours ago
3
flashlights make a cone... use that
– RedOculus
16 hours ago
10
@Harper "Allergic" isn't really the right term - it's not an immune system response or anything, or even an evolved response. It's the buildup of carbonic acid, which forms when there's a bunch of CO2 dissolved in water.
– Delioth
15 hours ago
69
69
CO2 is very much not "just compressed air".
– T.J.L.
23 hours ago
CO2 is very much not "just compressed air".
– T.J.L.
23 hours ago
4
4
Are you doing this indoors or outdoors?
– thosphor
21 hours ago
Are you doing this indoors or outdoors?
– thosphor
21 hours ago
8
8
CO2 isn't just an oxygen displacer, humans are also allergic to it. That "OMG must breathe" sensation you get when you are not breathing, is not a lack of oxygen... actually there's still plenty of oxygen. That feeling is caused by the buildup of CO2 in not particularly high concentrations. It serves as a substitute for an oxygen density detector, which would've been evolutionarily harder to evolve.
– Harper
17 hours ago
CO2 isn't just an oxygen displacer, humans are also allergic to it. That "OMG must breathe" sensation you get when you are not breathing, is not a lack of oxygen... actually there's still plenty of oxygen. That feeling is caused by the buildup of CO2 in not particularly high concentrations. It serves as a substitute for an oxygen density detector, which would've been evolutionarily harder to evolve.
– Harper
17 hours ago
3
3
flashlights make a cone... use that
– RedOculus
16 hours ago
flashlights make a cone... use that
– RedOculus
16 hours ago
10
10
@Harper "Allergic" isn't really the right term - it's not an immune system response or anything, or even an evolved response. It's the buildup of carbonic acid, which forms when there's a bunch of CO2 dissolved in water.
– Delioth
15 hours ago
@Harper "Allergic" isn't really the right term - it's not an immune system response or anything, or even an evolved response. It's the buildup of carbonic acid, which forms when there's a bunch of CO2 dissolved in water.
– Delioth
15 hours ago
 |Â
show 4 more comments
3 Answers
3
active
oldest
votes
up vote
82
down vote
CO2 extinguishers are not safe to use on people or in a room full of people.
Exit temperatures of the CO2 is -52°C in gaseous form and -78°C in snow form, enough to cause frostbite if it touches the skin. If that happens, it is recommended to remove most of it without rubbing it in and then seek medical advice.
It can also cause respiratory problems, especially among person who already have some troubles such as asthma, because the CO2 is not “basically just compressed airâ€Â—it's compressed carbon dioxide, and the fire extinguisher works by replacing the oxygen in the area to put out the fire. A CO2 fire extinguisher aimed at people would work by replacing the oxygen nearby those people with CO2. This gas is an asphyxiant and unhealthy even in low concentrations. From a USA EPA report (source 2), high concentration exposure has ill effects, and people would be exposed to high concentration if the fire extinguisher is being pointed at them:
At concentrations greater than 17 percent, such as those encountered during carbon dioxide fire suppressant use, loss of controlled and purposeful activity, unconsciousness, convulsions, coma, and death occur within 1 minute of initial inhalation of carbon dioxide
The same paragraph continues, but even low concentration exposure is detrimental (ibid.):
Exposures to 4 to 7 percent carbon dioxide can result in headache; hearing and visual disturbances; increased blood pressure; dyspnea, or difficulty breathing; mental depression; and tremors
This occurs even with sufficient exposure to oxygen. “Exposures to 4 to 7 percent carbon dioxide†here imply only 4–7% of the air inhaled is CO2.
While the risk is low when used outside, it is recommended to always open doors and windows wide if it's been used indoors to evacuate the CO2 and bring in fresh air.
Sources:
INRS file on fire extinguishers (PDF, in French). INRS = l’Institut national de recherche et de sécurité pour la prévention des accidents du travail et des maladies professionnelles2. In English it is the French National Research and Safety Institute for the Prevention of Occupational Accidents and Diseases3.- Carbon Dioxide as a Fire Suppressant: Examining the Risks, by the US Environmental Protection Agency
edited 6 mins ago
doppelspooker♦
31.4k11134222
answered 23 hours ago
Sava
674413
3
"enough to cause frostbite if it touches the skin" - For a sustained duration in a single spot, yes. However that's actually less likely to occur than it seems due to the fact that the solid CO2 will begin to vaporize the instant it touches anything as warm as a person. You can safely 'hold' a small piece of dry ice in your bare hands, even, so long as you don't let it sit in one spot.
– aroth
22 hours ago
How long is a 'sustained duration'? If it's used to figure some aoe effect, then the people in the affected area will probably stand in the cloud for longer than a few seconds. Even more if there's repeated use of the weapon in question, or just repeated use of the extinguisher because the effect isn't over yet in game time, since there was a pause to discuss rules or something.
– Sava
21 hours ago
2
@aroth don't forget emotional factor. Burning NPC monster that just scared you with your fire spell / extinguisher? Recipe for a frostbite, even if everyone tried to be responsible adults.
– Mołot
20 hours ago
7
"Humans can't breathe this gas, and a fire extinguisher aimed at people would work by replacing the oxygen nearby those people with unbreathable CO2." - It's a bit more serious than that; CO2 is actually toxic to humans. Key quote: "Concentrations of 7% to 10% may cause suffocation, even in the presence of sufficient oxygen, manifesting as dizziness, headache, visual and hearing dysfunction, and unconsciousness within a few minutes to an hour."
– marcelm
13 hours ago
1
@marcelm the exact wording is actually not a toxic gas but an asphyxiant gas. However, the key point is it can kill you in 10% or lower concentrations.
– Nelson
11 hours ago
 |Â
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up vote
43
down vote
In answer to your question on the safety of using a CO2 extinguisher as a breath weapon effect at a Live Roleplaying Event: NO, for exactly the reasons stated in the other answers - extreme cold, hypoxia, and CO2 poisoning. I don't think your insurers would be too pleased about that particular course of action, either.
From the point of view of a someone who rigs effects for a large system, what you probably want instead is a portable smoke machine. These can be hired relatively inexpensively, and use a water-based smoke-fuel to provide the effect. If you're technically inclined, you can even make one yourself.
The other way - slightly less directed, but I have seen used as poison clouds at events - is a smoke grenade such as one you might get for use at an Airsoft shoot.
Both of these should be covered under your event insurance.
edited 9 hours ago
Anoplexian
1034
answered 21 hours ago
UselessInfoMine
39116
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1
Can a smoke machine be rigged to sort of 'shoot' smoke in a direction like an extinguisher would?
– Sava
21 hours ago
8
Absolutely. I use a variety of machines for the effects I rig - mainly the fixed appliances, but these do shoot smoke in a cone unless diffused by something in the way. They're exactly the same type of machine you get giving smoke at concerts, funfairs and clubs, so are also safe to use at fairly close range - a couple of feet. I still wouldn't blast someone in the face with it. :)
– UselessInfoMine
20 hours ago
12
As a brief thought, you might want to warn any asthmatics at your event that you will be using smoke effects, but it's less likely to cause as many problems as CO2 - Out of the few thousand who attend the events, I'm only aware of a couple who don't get on with the smoke effects.
– UselessInfoMine
20 hours ago
1
+1 for mention of insurance issues. This answer could be improved by emphasizing that, and the possibility of pre-existing safety regulations at the hosting location. These are strong reasons not to do this, beyond the simple safety aspects.
– Novak
19 hours ago
5
I think you should add that smoke machines/grenades can cause problems for people with asthma or other respiratory issues. If you use them, there should definitely be a warning so people with sensitivities know to avoid those activities.
– Ethan
16 hours ago
 |Â
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30
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DISCLAIMER: I am not a medical or safety professional.
They can be very dangerous
I would not recommend doing this. CO2 Fire extinguishers present 2 basic hazards.
Cold Burns
Do Not Touch the horn (the part that sprays CO2) when spraying a CO2 Fire extinguisher. The horn of a CO2 fire extinguisher becomes extremely cold during use, and can cause cold burns if skin comes into contact with it.
Additionally, while the CO2 rapidly warms once it is clear of the extinguisher, it is very hazardous at close range. You are spraying rapidly-evaporating dry ice out of this thing, which will cause cold-burns.
They displace oxygen.
This is the greater risk. The way a CO2 Fire Extinguisher works is that it pushes all of the oxygen in an area away, replacing it with CO2, thereby smothering the fire. This is obviously a problem, because humans need to breathe oxygen.
Based off this, here are two safety pointers if you do decide to point one of these at a person.
- Only use in a large, extremely well-ventilated area. Ideally, outdoors. In a confined space, a CO2 Fire extinguisher can lower the oxygen content of the space far enough to cause asphyxiation
- Do not sustain the spray for more than a few seconds at a time. Even in a well-ventilated area, the space that the extinguisher is spraying will quickly have too little oxygen to sustain a person. Sustained spraying can suffocate a person.
IMPORTANT: The CO2 continues traveling even after it is no longer visible as a cloud. Just because you can't see that you're spraying someone or something doesn't mean you aren't.
As an addition (with thanks to @supercat), CO2 is hazardous on its own, even in concentrations less than those required to leave a person hypoxic. If at any point, the air reaches a 10% concentration of CO2 or greater, the CDC qualifies that as 'Immediately Life Threatening.'
Conclusion
I would not, personally, recommend doing this.
But if you do, do so only in a very large and well ventilated space, stay several feet away from anyone while using it, and never spray for more than a few seconds at a time.
answered 23 hours ago
guildsbounty
31.1k5130155
15
For another example of people not realizing the dangers of simple asphyxiants, pouring liquid nitrogen in a pool creates a cool fog effect but can cause swimmers to pass out and fall into a pool and possibly drown.
– Captain Man
22 hours ago
3
Minor nit: CO2 does not cause asphyxiation by displacing oxygen, but rather by triggering respiratory spasms when atmospheric concentrations exceed blood concentration. This is why spacecraft and submarines need CO2 scrubbers in addition to an oxygen supply/generator.
– supercat
20 hours ago
4
@supercat It will, that's the point of a fire extinguisher. It does also act as a coolant, but the main point is for it to displace enough oxygen so fire doesn't spread. CO2 does indeed cause breathing problems in humans, but so does a lack of O2 caused by CO2 displacing it.
– Cubic
20 hours ago
8
@Cubic: According to OSHA, displacing 5-20% of the oxygen in a space will cause symptoms of hypoxia in someone engaged in physical exertion (presumably significantly faster at 20% than 10%). The CDC classifies a 10% concentration of CO2 is immediately life threatening. The concentration CO2 required to put out fires is sufficient to displace too much oxygen to sustain life, but CO2 can be rapidly fatal in concentrations below that.
– supercat
20 hours ago
4
@Malandy: No, because without the CO2 they wouldn't immediately pass out or start gasping for air; they would proceed into the room, start feeling weird, and eventually black out before realizing that there was no oxygen. Our bodies can't actually detect a lack of oxygen in the air, but they do detect excessive CO2.
– kundor
8 hours ago
 |Â
show 6 more comments
3 Answers
3
active
oldest
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3 Answers
3
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
82
down vote
CO2 extinguishers are not safe to use on people or in a room full of people.
Exit temperatures of the CO2 is -52°C in gaseous form and -78°C in snow form, enough to cause frostbite if it touches the skin. If that happens, it is recommended to remove most of it without rubbing it in and then seek medical advice.
It can also cause respiratory problems, especially among person who already have some troubles such as asthma, because the CO2 is not “basically just compressed airâ€Â—it's compressed carbon dioxide, and the fire extinguisher works by replacing the oxygen in the area to put out the fire. A CO2 fire extinguisher aimed at people would work by replacing the oxygen nearby those people with CO2. This gas is an asphyxiant and unhealthy even in low concentrations. From a USA EPA report (source 2), high concentration exposure has ill effects, and people would be exposed to high concentration if the fire extinguisher is being pointed at them:
At concentrations greater than 17 percent, such as those encountered during carbon dioxide fire suppressant use, loss of controlled and purposeful activity, unconsciousness, convulsions, coma, and death occur within 1 minute of initial inhalation of carbon dioxide
The same paragraph continues, but even low concentration exposure is detrimental (ibid.):
Exposures to 4 to 7 percent carbon dioxide can result in headache; hearing and visual disturbances; increased blood pressure; dyspnea, or difficulty breathing; mental depression; and tremors
This occurs even with sufficient exposure to oxygen. “Exposures to 4 to 7 percent carbon dioxide†here imply only 4–7% of the air inhaled is CO2.
While the risk is low when used outside, it is recommended to always open doors and windows wide if it's been used indoors to evacuate the CO2 and bring in fresh air.
Sources:
INRS file on fire extinguishers (PDF, in French). INRS = l’Institut national de recherche et de sécurité pour la prévention des accidents du travail et des maladies professionnelles2. In English it is the French National Research and Safety Institute for the Prevention of Occupational Accidents and Diseases3.- Carbon Dioxide as a Fire Suppressant: Examining the Risks, by the US Environmental Protection Agency
edited 6 mins ago
doppelspooker♦
31.4k11134222
answered 23 hours ago
Sava
674413
3
"enough to cause frostbite if it touches the skin" - For a sustained duration in a single spot, yes. However that's actually less likely to occur than it seems due to the fact that the solid CO2 will begin to vaporize the instant it touches anything as warm as a person. You can safely 'hold' a small piece of dry ice in your bare hands, even, so long as you don't let it sit in one spot.
– aroth
22 hours ago
How long is a 'sustained duration'? If it's used to figure some aoe effect, then the people in the affected area will probably stand in the cloud for longer than a few seconds. Even more if there's repeated use of the weapon in question, or just repeated use of the extinguisher because the effect isn't over yet in game time, since there was a pause to discuss rules or something.
– Sava
21 hours ago
2
@aroth don't forget emotional factor. Burning NPC monster that just scared you with your fire spell / extinguisher? Recipe for a frostbite, even if everyone tried to be responsible adults.
– Mołot
20 hours ago
7
"Humans can't breathe this gas, and a fire extinguisher aimed at people would work by replacing the oxygen nearby those people with unbreathable CO2." - It's a bit more serious than that; CO2 is actually toxic to humans. Key quote: "Concentrations of 7% to 10% may cause suffocation, even in the presence of sufficient oxygen, manifesting as dizziness, headache, visual and hearing dysfunction, and unconsciousness within a few minutes to an hour."
– marcelm
13 hours ago
1
@marcelm the exact wording is actually not a toxic gas but an asphyxiant gas. However, the key point is it can kill you in 10% or lower concentrations.
– Nelson
11 hours ago
 |Â
show 2 more comments
up vote
82
down vote
CO2 extinguishers are not safe to use on people or in a room full of people.
Exit temperatures of the CO2 is -52°C in gaseous form and -78°C in snow form, enough to cause frostbite if it touches the skin. If that happens, it is recommended to remove most of it without rubbing it in and then seek medical advice.
It can also cause respiratory problems, especially among person who already have some troubles such as asthma, because the CO2 is not “basically just compressed airâ€Â—it's compressed carbon dioxide, and the fire extinguisher works by replacing the oxygen in the area to put out the fire. A CO2 fire extinguisher aimed at people would work by replacing the oxygen nearby those people with CO2. This gas is an asphyxiant and unhealthy even in low concentrations. From a USA EPA report (source 2), high concentration exposure has ill effects, and people would be exposed to high concentration if the fire extinguisher is being pointed at them:
At concentrations greater than 17 percent, such as those encountered during carbon dioxide fire suppressant use, loss of controlled and purposeful activity, unconsciousness, convulsions, coma, and death occur within 1 minute of initial inhalation of carbon dioxide
The same paragraph continues, but even low concentration exposure is detrimental (ibid.):
Exposures to 4 to 7 percent carbon dioxide can result in headache; hearing and visual disturbances; increased blood pressure; dyspnea, or difficulty breathing; mental depression; and tremors
This occurs even with sufficient exposure to oxygen. “Exposures to 4 to 7 percent carbon dioxide†here imply only 4–7% of the air inhaled is CO2.
While the risk is low when used outside, it is recommended to always open doors and windows wide if it's been used indoors to evacuate the CO2 and bring in fresh air.
Sources:
INRS file on fire extinguishers (PDF, in French). INRS = l’Institut national de recherche et de sécurité pour la prévention des accidents du travail et des maladies professionnelles2. In English it is the French National Research and Safety Institute for the Prevention of Occupational Accidents and Diseases3.- Carbon Dioxide as a Fire Suppressant: Examining the Risks, by the US Environmental Protection Agency
edited 6 mins ago
doppelspooker♦
31.4k11134222
answered 23 hours ago
Sava
674413
3
"enough to cause frostbite if it touches the skin" - For a sustained duration in a single spot, yes. However that's actually less likely to occur than it seems due to the fact that the solid CO2 will begin to vaporize the instant it touches anything as warm as a person. You can safely 'hold' a small piece of dry ice in your bare hands, even, so long as you don't let it sit in one spot.
– aroth
22 hours ago
How long is a 'sustained duration'? If it's used to figure some aoe effect, then the people in the affected area will probably stand in the cloud for longer than a few seconds. Even more if there's repeated use of the weapon in question, or just repeated use of the extinguisher because the effect isn't over yet in game time, since there was a pause to discuss rules or something.
– Sava
21 hours ago
2
@aroth don't forget emotional factor. Burning NPC monster that just scared you with your fire spell / extinguisher? Recipe for a frostbite, even if everyone tried to be responsible adults.
– Mołot
20 hours ago
7
"Humans can't breathe this gas, and a fire extinguisher aimed at people would work by replacing the oxygen nearby those people with unbreathable CO2." - It's a bit more serious than that; CO2 is actually toxic to humans. Key quote: "Concentrations of 7% to 10% may cause suffocation, even in the presence of sufficient oxygen, manifesting as dizziness, headache, visual and hearing dysfunction, and unconsciousness within a few minutes to an hour."
– marcelm
13 hours ago
1
@marcelm the exact wording is actually not a toxic gas but an asphyxiant gas. However, the key point is it can kill you in 10% or lower concentrations.
– Nelson
11 hours ago
 |Â
show 2 more comments
up vote
82
down vote
up vote
82
down vote
CO2 extinguishers are not safe to use on people or in a room full of people.
Exit temperatures of the CO2 is -52°C in gaseous form and -78°C in snow form, enough to cause frostbite if it touches the skin. If that happens, it is recommended to remove most of it without rubbing it in and then seek medical advice.
It can also cause respiratory problems, especially among person who already have some troubles such as asthma, because the CO2 is not “basically just compressed airâ€Â—it's compressed carbon dioxide, and the fire extinguisher works by replacing the oxygen in the area to put out the fire. A CO2 fire extinguisher aimed at people would work by replacing the oxygen nearby those people with CO2. This gas is an asphyxiant and unhealthy even in low concentrations. From a USA EPA report (source 2), high concentration exposure has ill effects, and people would be exposed to high concentration if the fire extinguisher is being pointed at them:
At concentrations greater than 17 percent, such as those encountered during carbon dioxide fire suppressant use, loss of controlled and purposeful activity, unconsciousness, convulsions, coma, and death occur within 1 minute of initial inhalation of carbon dioxide
The same paragraph continues, but even low concentration exposure is detrimental (ibid.):
Exposures to 4 to 7 percent carbon dioxide can result in headache; hearing and visual disturbances; increased blood pressure; dyspnea, or difficulty breathing; mental depression; and tremors
This occurs even with sufficient exposure to oxygen. “Exposures to 4 to 7 percent carbon dioxide†here imply only 4–7% of the air inhaled is CO2.
While the risk is low when used outside, it is recommended to always open doors and windows wide if it's been used indoors to evacuate the CO2 and bring in fresh air.
Sources:
INRS file on fire extinguishers (PDF, in French). INRS = l’Institut national de recherche et de sécurité pour la prévention des accidents du travail et des maladies professionnelles2. In English it is the French National Research and Safety Institute for the Prevention of Occupational Accidents and Diseases3.- Carbon Dioxide as a Fire Suppressant: Examining the Risks, by the US Environmental Protection Agency
edited 6 mins ago
doppelspooker♦
31.4k11134222
answered 23 hours ago
Sava
674413
CO2 extinguishers are not safe to use on people or in a room full of people.
Exit temperatures of the CO2 is -52°C in gaseous form and -78°C in snow form, enough to cause frostbite if it touches the skin. If that happens, it is recommended to remove most of it without rubbing it in and then seek medical advice.
It can also cause respiratory problems, especially among person who already have some troubles such as asthma, because the CO2 is not “basically just compressed airâ€Â—it's compressed carbon dioxide, and the fire extinguisher works by replacing the oxygen in the area to put out the fire. A CO2 fire extinguisher aimed at people would work by replacing the oxygen nearby those people with CO2. This gas is an asphyxiant and unhealthy even in low concentrations. From a USA EPA report (source 2), high concentration exposure has ill effects, and people would be exposed to high concentration if the fire extinguisher is being pointed at them:
At concentrations greater than 17 percent, such as those encountered during carbon dioxide fire suppressant use, loss of controlled and purposeful activity, unconsciousness, convulsions, coma, and death occur within 1 minute of initial inhalation of carbon dioxide
The same paragraph continues, but even low concentration exposure is detrimental (ibid.):
Exposures to 4 to 7 percent carbon dioxide can result in headache; hearing and visual disturbances; increased blood pressure; dyspnea, or difficulty breathing; mental depression; and tremors
This occurs even with sufficient exposure to oxygen. “Exposures to 4 to 7 percent carbon dioxide†here imply only 4–7% of the air inhaled is CO2.
While the risk is low when used outside, it is recommended to always open doors and windows wide if it's been used indoors to evacuate the CO2 and bring in fresh air.
Sources:
INRS file on fire extinguishers (PDF, in French). INRS = l’Institut national de recherche et de sécurité pour la prévention des accidents du travail et des maladies professionnelles2. In English it is the French National Research and Safety Institute for the Prevention of Occupational Accidents and Diseases3.- Carbon Dioxide as a Fire Suppressant: Examining the Risks, by the US Environmental Protection Agency
edited 6 mins ago
doppelspooker♦
31.4k11134222
answered 23 hours ago
Sava
674413
edited 6 mins ago
doppelspooker♦
31.4k11134222
edited 6 mins ago
doppelspooker♦
31.4k11134222
edited 6 mins ago
doppelspooker♦
31.4k11134222
31.4k11134222
answered 23 hours ago
Sava
674413
answered 23 hours ago
Sava
674413
answered 23 hours ago
Sava
674413
674413
3
"enough to cause frostbite if it touches the skin" - For a sustained duration in a single spot, yes. However that's actually less likely to occur than it seems due to the fact that the solid CO2 will begin to vaporize the instant it touches anything as warm as a person. You can safely 'hold' a small piece of dry ice in your bare hands, even, so long as you don't let it sit in one spot.
– aroth
22 hours ago
How long is a 'sustained duration'? If it's used to figure some aoe effect, then the people in the affected area will probably stand in the cloud for longer than a few seconds. Even more if there's repeated use of the weapon in question, or just repeated use of the extinguisher because the effect isn't over yet in game time, since there was a pause to discuss rules or something.
– Sava
21 hours ago
2
@aroth don't forget emotional factor. Burning NPC monster that just scared you with your fire spell / extinguisher? Recipe for a frostbite, even if everyone tried to be responsible adults.
– Mołot
20 hours ago
7
"Humans can't breathe this gas, and a fire extinguisher aimed at people would work by replacing the oxygen nearby those people with unbreathable CO2." - It's a bit more serious than that; CO2 is actually toxic to humans. Key quote: "Concentrations of 7% to 10% may cause suffocation, even in the presence of sufficient oxygen, manifesting as dizziness, headache, visual and hearing dysfunction, and unconsciousness within a few minutes to an hour."
– marcelm
13 hours ago
1
@marcelm the exact wording is actually not a toxic gas but an asphyxiant gas. However, the key point is it can kill you in 10% or lower concentrations.
– Nelson
11 hours ago
 |Â
show 2 more comments
3
"enough to cause frostbite if it touches the skin" - For a sustained duration in a single spot, yes. However that's actually less likely to occur than it seems due to the fact that the solid CO2 will begin to vaporize the instant it touches anything as warm as a person. You can safely 'hold' a small piece of dry ice in your bare hands, even, so long as you don't let it sit in one spot.
– aroth
22 hours ago
How long is a 'sustained duration'? If it's used to figure some aoe effect, then the people in the affected area will probably stand in the cloud for longer than a few seconds. Even more if there's repeated use of the weapon in question, or just repeated use of the extinguisher because the effect isn't over yet in game time, since there was a pause to discuss rules or something.
– Sava
21 hours ago
2
@aroth don't forget emotional factor. Burning NPC monster that just scared you with your fire spell / extinguisher? Recipe for a frostbite, even if everyone tried to be responsible adults.
– Mołot
20 hours ago
7
"Humans can't breathe this gas, and a fire extinguisher aimed at people would work by replacing the oxygen nearby those people with unbreathable CO2." - It's a bit more serious than that; CO2 is actually toxic to humans. Key quote: "Concentrations of 7% to 10% may cause suffocation, even in the presence of sufficient oxygen, manifesting as dizziness, headache, visual and hearing dysfunction, and unconsciousness within a few minutes to an hour."
– marcelm
13 hours ago
1
@marcelm the exact wording is actually not a toxic gas but an asphyxiant gas. However, the key point is it can kill you in 10% or lower concentrations.
– Nelson
11 hours ago
3
3
"enough to cause frostbite if it touches the skin" - For a sustained duration in a single spot, yes. However that's actually less likely to occur than it seems due to the fact that the solid CO2 will begin to vaporize the instant it touches anything as warm as a person. You can safely 'hold' a small piece of dry ice in your bare hands, even, so long as you don't let it sit in one spot.
– aroth
22 hours ago
"enough to cause frostbite if it touches the skin" - For a sustained duration in a single spot, yes. However that's actually less likely to occur than it seems due to the fact that the solid CO2 will begin to vaporize the instant it touches anything as warm as a person. You can safely 'hold' a small piece of dry ice in your bare hands, even, so long as you don't let it sit in one spot.
– aroth
22 hours ago
How long is a 'sustained duration'? If it's used to figure some aoe effect, then the people in the affected area will probably stand in the cloud for longer than a few seconds. Even more if there's repeated use of the weapon in question, or just repeated use of the extinguisher because the effect isn't over yet in game time, since there was a pause to discuss rules or something.
– Sava
21 hours ago
How long is a 'sustained duration'? If it's used to figure some aoe effect, then the people in the affected area will probably stand in the cloud for longer than a few seconds. Even more if there's repeated use of the weapon in question, or just repeated use of the extinguisher because the effect isn't over yet in game time, since there was a pause to discuss rules or something.
– Sava
21 hours ago
2
2
@aroth don't forget emotional factor. Burning NPC monster that just scared you with your fire spell / extinguisher? Recipe for a frostbite, even if everyone tried to be responsible adults.
– Mołot
20 hours ago
@aroth don't forget emotional factor. Burning NPC monster that just scared you with your fire spell / extinguisher? Recipe for a frostbite, even if everyone tried to be responsible adults.
– Mołot
20 hours ago
7
7
"Humans can't breathe this gas, and a fire extinguisher aimed at people would work by replacing the oxygen nearby those people with unbreathable CO2." - It's a bit more serious than that; CO2 is actually toxic to humans. Key quote: "Concentrations of 7% to 10% may cause suffocation, even in the presence of sufficient oxygen, manifesting as dizziness, headache, visual and hearing dysfunction, and unconsciousness within a few minutes to an hour."
– marcelm
13 hours ago
"Humans can't breathe this gas, and a fire extinguisher aimed at people would work by replacing the oxygen nearby those people with unbreathable CO2." - It's a bit more serious than that; CO2 is actually toxic to humans. Key quote: "Concentrations of 7% to 10% may cause suffocation, even in the presence of sufficient oxygen, manifesting as dizziness, headache, visual and hearing dysfunction, and unconsciousness within a few minutes to an hour."
– marcelm
13 hours ago
1
1
@marcelm the exact wording is actually not a toxic gas but an asphyxiant gas. However, the key point is it can kill you in 10% or lower concentrations.
– Nelson
11 hours ago
@marcelm the exact wording is actually not a toxic gas but an asphyxiant gas. However, the key point is it can kill you in 10% or lower concentrations.
– Nelson
11 hours ago
 |Â
show 2 more comments
up vote
43
down vote
In answer to your question on the safety of using a CO2 extinguisher as a breath weapon effect at a Live Roleplaying Event: NO, for exactly the reasons stated in the other answers - extreme cold, hypoxia, and CO2 poisoning. I don't think your insurers would be too pleased about that particular course of action, either.
From the point of view of a someone who rigs effects for a large system, what you probably want instead is a portable smoke machine. These can be hired relatively inexpensively, and use a water-based smoke-fuel to provide the effect. If you're technically inclined, you can even make one yourself.
The other way - slightly less directed, but I have seen used as poison clouds at events - is a smoke grenade such as one you might get for use at an Airsoft shoot.
Both of these should be covered under your event insurance.
edited 9 hours ago
Anoplexian
1034
answered 21 hours ago
UselessInfoMine
39116
New contributor
UselessInfoMine is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
1
Can a smoke machine be rigged to sort of 'shoot' smoke in a direction like an extinguisher would?
– Sava
21 hours ago
8
Absolutely. I use a variety of machines for the effects I rig - mainly the fixed appliances, but these do shoot smoke in a cone unless diffused by something in the way. They're exactly the same type of machine you get giving smoke at concerts, funfairs and clubs, so are also safe to use at fairly close range - a couple of feet. I still wouldn't blast someone in the face with it. :)
– UselessInfoMine
20 hours ago
12
As a brief thought, you might want to warn any asthmatics at your event that you will be using smoke effects, but it's less likely to cause as many problems as CO2 - Out of the few thousand who attend the events, I'm only aware of a couple who don't get on with the smoke effects.
– UselessInfoMine
20 hours ago
1
+1 for mention of insurance issues. This answer could be improved by emphasizing that, and the possibility of pre-existing safety regulations at the hosting location. These are strong reasons not to do this, beyond the simple safety aspects.
– Novak
19 hours ago
5
I think you should add that smoke machines/grenades can cause problems for people with asthma or other respiratory issues. If you use them, there should definitely be a warning so people with sensitivities know to avoid those activities.
– Ethan
16 hours ago
 |Â
show 4 more comments
up vote
43
down vote
In answer to your question on the safety of using a CO2 extinguisher as a breath weapon effect at a Live Roleplaying Event: NO, for exactly the reasons stated in the other answers - extreme cold, hypoxia, and CO2 poisoning. I don't think your insurers would be too pleased about that particular course of action, either.
From the point of view of a someone who rigs effects for a large system, what you probably want instead is a portable smoke machine. These can be hired relatively inexpensively, and use a water-based smoke-fuel to provide the effect. If you're technically inclined, you can even make one yourself.
The other way - slightly less directed, but I have seen used as poison clouds at events - is a smoke grenade such as one you might get for use at an Airsoft shoot.
Both of these should be covered under your event insurance.
edited 9 hours ago
Anoplexian
1034
answered 21 hours ago
UselessInfoMine
39116
New contributor
UselessInfoMine is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
1
Can a smoke machine be rigged to sort of 'shoot' smoke in a direction like an extinguisher would?
– Sava
21 hours ago
8
Absolutely. I use a variety of machines for the effects I rig - mainly the fixed appliances, but these do shoot smoke in a cone unless diffused by something in the way. They're exactly the same type of machine you get giving smoke at concerts, funfairs and clubs, so are also safe to use at fairly close range - a couple of feet. I still wouldn't blast someone in the face with it. :)
– UselessInfoMine
20 hours ago
12
As a brief thought, you might want to warn any asthmatics at your event that you will be using smoke effects, but it's less likely to cause as many problems as CO2 - Out of the few thousand who attend the events, I'm only aware of a couple who don't get on with the smoke effects.
– UselessInfoMine
20 hours ago
1
+1 for mention of insurance issues. This answer could be improved by emphasizing that, and the possibility of pre-existing safety regulations at the hosting location. These are strong reasons not to do this, beyond the simple safety aspects.
– Novak
19 hours ago
5
I think you should add that smoke machines/grenades can cause problems for people with asthma or other respiratory issues. If you use them, there should definitely be a warning so people with sensitivities know to avoid those activities.
– Ethan
16 hours ago
 |Â
show 4 more comments
up vote
43
down vote
up vote
43
down vote
In answer to your question on the safety of using a CO2 extinguisher as a breath weapon effect at a Live Roleplaying Event: NO, for exactly the reasons stated in the other answers - extreme cold, hypoxia, and CO2 poisoning. I don't think your insurers would be too pleased about that particular course of action, either.
From the point of view of a someone who rigs effects for a large system, what you probably want instead is a portable smoke machine. These can be hired relatively inexpensively, and use a water-based smoke-fuel to provide the effect. If you're technically inclined, you can even make one yourself.
The other way - slightly less directed, but I have seen used as poison clouds at events - is a smoke grenade such as one you might get for use at an Airsoft shoot.
Both of these should be covered under your event insurance.
edited 9 hours ago
Anoplexian
1034
answered 21 hours ago
UselessInfoMine
39116
New contributor
UselessInfoMine is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
In answer to your question on the safety of using a CO2 extinguisher as a breath weapon effect at a Live Roleplaying Event: NO, for exactly the reasons stated in the other answers - extreme cold, hypoxia, and CO2 poisoning. I don't think your insurers would be too pleased about that particular course of action, either.
From the point of view of a someone who rigs effects for a large system, what you probably want instead is a portable smoke machine. These can be hired relatively inexpensively, and use a water-based smoke-fuel to provide the effect. If you're technically inclined, you can even make one yourself.
The other way - slightly less directed, but I have seen used as poison clouds at events - is a smoke grenade such as one you might get for use at an Airsoft shoot.
Both of these should be covered under your event insurance.
edited 9 hours ago
Anoplexian
1034
answered 21 hours ago
UselessInfoMine
39116
New contributor
UselessInfoMine is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
edited 9 hours ago
Anoplexian
1034
edited 9 hours ago
Anoplexian
1034
edited 9 hours ago
Anoplexian
1034
1034
answered 21 hours ago
UselessInfoMine
39116
New contributor
UselessInfoMine is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
answered 21 hours ago
UselessInfoMine
39116
answered 21 hours ago
UselessInfoMine
39116
39116
New contributor
UselessInfoMine is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
UselessInfoMine is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
UselessInfoMine is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
1
Can a smoke machine be rigged to sort of 'shoot' smoke in a direction like an extinguisher would?
– Sava
21 hours ago
8
Absolutely. I use a variety of machines for the effects I rig - mainly the fixed appliances, but these do shoot smoke in a cone unless diffused by something in the way. They're exactly the same type of machine you get giving smoke at concerts, funfairs and clubs, so are also safe to use at fairly close range - a couple of feet. I still wouldn't blast someone in the face with it. :)
– UselessInfoMine
20 hours ago
12
As a brief thought, you might want to warn any asthmatics at your event that you will be using smoke effects, but it's less likely to cause as many problems as CO2 - Out of the few thousand who attend the events, I'm only aware of a couple who don't get on with the smoke effects.
– UselessInfoMine
20 hours ago
1
+1 for mention of insurance issues. This answer could be improved by emphasizing that, and the possibility of pre-existing safety regulations at the hosting location. These are strong reasons not to do this, beyond the simple safety aspects.
– Novak
19 hours ago
5
I think you should add that smoke machines/grenades can cause problems for people with asthma or other respiratory issues. If you use them, there should definitely be a warning so people with sensitivities know to avoid those activities.
– Ethan
16 hours ago
 |Â
show 4 more comments
1
Can a smoke machine be rigged to sort of 'shoot' smoke in a direction like an extinguisher would?
– Sava
21 hours ago
8
Absolutely. I use a variety of machines for the effects I rig - mainly the fixed appliances, but these do shoot smoke in a cone unless diffused by something in the way. They're exactly the same type of machine you get giving smoke at concerts, funfairs and clubs, so are also safe to use at fairly close range - a couple of feet. I still wouldn't blast someone in the face with it. :)
– UselessInfoMine
20 hours ago
12
As a brief thought, you might want to warn any asthmatics at your event that you will be using smoke effects, but it's less likely to cause as many problems as CO2 - Out of the few thousand who attend the events, I'm only aware of a couple who don't get on with the smoke effects.
– UselessInfoMine
20 hours ago
1
+1 for mention of insurance issues. This answer could be improved by emphasizing that, and the possibility of pre-existing safety regulations at the hosting location. These are strong reasons not to do this, beyond the simple safety aspects.
– Novak
19 hours ago
5
I think you should add that smoke machines/grenades can cause problems for people with asthma or other respiratory issues. If you use them, there should definitely be a warning so people with sensitivities know to avoid those activities.
– Ethan
16 hours ago
1
1
Can a smoke machine be rigged to sort of 'shoot' smoke in a direction like an extinguisher would?
– Sava
21 hours ago
Can a smoke machine be rigged to sort of 'shoot' smoke in a direction like an extinguisher would?
– Sava
21 hours ago
8
8
Absolutely. I use a variety of machines for the effects I rig - mainly the fixed appliances, but these do shoot smoke in a cone unless diffused by something in the way. They're exactly the same type of machine you get giving smoke at concerts, funfairs and clubs, so are also safe to use at fairly close range - a couple of feet. I still wouldn't blast someone in the face with it. :)
– UselessInfoMine
20 hours ago
Absolutely. I use a variety of machines for the effects I rig - mainly the fixed appliances, but these do shoot smoke in a cone unless diffused by something in the way. They're exactly the same type of machine you get giving smoke at concerts, funfairs and clubs, so are also safe to use at fairly close range - a couple of feet. I still wouldn't blast someone in the face with it. :)
– UselessInfoMine
20 hours ago
12
12
As a brief thought, you might want to warn any asthmatics at your event that you will be using smoke effects, but it's less likely to cause as many problems as CO2 - Out of the few thousand who attend the events, I'm only aware of a couple who don't get on with the smoke effects.
– UselessInfoMine
20 hours ago
As a brief thought, you might want to warn any asthmatics at your event that you will be using smoke effects, but it's less likely to cause as many problems as CO2 - Out of the few thousand who attend the events, I'm only aware of a couple who don't get on with the smoke effects.
– UselessInfoMine
20 hours ago
1
1
+1 for mention of insurance issues. This answer could be improved by emphasizing that, and the possibility of pre-existing safety regulations at the hosting location. These are strong reasons not to do this, beyond the simple safety aspects.
– Novak
19 hours ago
+1 for mention of insurance issues. This answer could be improved by emphasizing that, and the possibility of pre-existing safety regulations at the hosting location. These are strong reasons not to do this, beyond the simple safety aspects.
– Novak
19 hours ago
5
5
I think you should add that smoke machines/grenades can cause problems for people with asthma or other respiratory issues. If you use them, there should definitely be a warning so people with sensitivities know to avoid those activities.
– Ethan
16 hours ago
I think you should add that smoke machines/grenades can cause problems for people with asthma or other respiratory issues. If you use them, there should definitely be a warning so people with sensitivities know to avoid those activities.
– Ethan
16 hours ago
 |Â
show 4 more comments
up vote
30
down vote
DISCLAIMER: I am not a medical or safety professional.
They can be very dangerous
I would not recommend doing this. CO2 Fire extinguishers present 2 basic hazards.
Cold Burns
Do Not Touch the horn (the part that sprays CO2) when spraying a CO2 Fire extinguisher. The horn of a CO2 fire extinguisher becomes extremely cold during use, and can cause cold burns if skin comes into contact with it.
Additionally, while the CO2 rapidly warms once it is clear of the extinguisher, it is very hazardous at close range. You are spraying rapidly-evaporating dry ice out of this thing, which will cause cold-burns.
They displace oxygen.
This is the greater risk. The way a CO2 Fire Extinguisher works is that it pushes all of the oxygen in an area away, replacing it with CO2, thereby smothering the fire. This is obviously a problem, because humans need to breathe oxygen.
Based off this, here are two safety pointers if you do decide to point one of these at a person.
- Only use in a large, extremely well-ventilated area. Ideally, outdoors. In a confined space, a CO2 Fire extinguisher can lower the oxygen content of the space far enough to cause asphyxiation
- Do not sustain the spray for more than a few seconds at a time. Even in a well-ventilated area, the space that the extinguisher is spraying will quickly have too little oxygen to sustain a person. Sustained spraying can suffocate a person.
IMPORTANT: The CO2 continues traveling even after it is no longer visible as a cloud. Just because you can't see that you're spraying someone or something doesn't mean you aren't.
As an addition (with thanks to @supercat), CO2 is hazardous on its own, even in concentrations less than those required to leave a person hypoxic. If at any point, the air reaches a 10% concentration of CO2 or greater, the CDC qualifies that as 'Immediately Life Threatening.'
Conclusion
I would not, personally, recommend doing this.
But if you do, do so only in a very large and well ventilated space, stay several feet away from anyone while using it, and never spray for more than a few seconds at a time.
answered 23 hours ago
guildsbounty
31.1k5130155
15
For another example of people not realizing the dangers of simple asphyxiants, pouring liquid nitrogen in a pool creates a cool fog effect but can cause swimmers to pass out and fall into a pool and possibly drown.
– Captain Man
22 hours ago
3
Minor nit: CO2 does not cause asphyxiation by displacing oxygen, but rather by triggering respiratory spasms when atmospheric concentrations exceed blood concentration. This is why spacecraft and submarines need CO2 scrubbers in addition to an oxygen supply/generator.
– supercat
20 hours ago
4
@supercat It will, that's the point of a fire extinguisher. It does also act as a coolant, but the main point is for it to displace enough oxygen so fire doesn't spread. CO2 does indeed cause breathing problems in humans, but so does a lack of O2 caused by CO2 displacing it.
– Cubic
20 hours ago
8
@Cubic: According to OSHA, displacing 5-20% of the oxygen in a space will cause symptoms of hypoxia in someone engaged in physical exertion (presumably significantly faster at 20% than 10%). The CDC classifies a 10% concentration of CO2 is immediately life threatening. The concentration CO2 required to put out fires is sufficient to displace too much oxygen to sustain life, but CO2 can be rapidly fatal in concentrations below that.
– supercat
20 hours ago
4
@Malandy: No, because without the CO2 they wouldn't immediately pass out or start gasping for air; they would proceed into the room, start feeling weird, and eventually black out before realizing that there was no oxygen. Our bodies can't actually detect a lack of oxygen in the air, but they do detect excessive CO2.
– kundor
8 hours ago
 |Â
show 6 more comments
up vote
30
down vote
DISCLAIMER: I am not a medical or safety professional.
They can be very dangerous
I would not recommend doing this. CO2 Fire extinguishers present 2 basic hazards.
Cold Burns
Do Not Touch the horn (the part that sprays CO2) when spraying a CO2 Fire extinguisher. The horn of a CO2 fire extinguisher becomes extremely cold during use, and can cause cold burns if skin comes into contact with it.
Additionally, while the CO2 rapidly warms once it is clear of the extinguisher, it is very hazardous at close range. You are spraying rapidly-evaporating dry ice out of this thing, which will cause cold-burns.
They displace oxygen.
This is the greater risk. The way a CO2 Fire Extinguisher works is that it pushes all of the oxygen in an area away, replacing it with CO2, thereby smothering the fire. This is obviously a problem, because humans need to breathe oxygen.
Based off this, here are two safety pointers if you do decide to point one of these at a person.
- Only use in a large, extremely well-ventilated area. Ideally, outdoors. In a confined space, a CO2 Fire extinguisher can lower the oxygen content of the space far enough to cause asphyxiation
- Do not sustain the spray for more than a few seconds at a time. Even in a well-ventilated area, the space that the extinguisher is spraying will quickly have too little oxygen to sustain a person. Sustained spraying can suffocate a person.
IMPORTANT: The CO2 continues traveling even after it is no longer visible as a cloud. Just because you can't see that you're spraying someone or something doesn't mean you aren't.
As an addition (with thanks to @supercat), CO2 is hazardous on its own, even in concentrations less than those required to leave a person hypoxic. If at any point, the air reaches a 10% concentration of CO2 or greater, the CDC qualifies that as 'Immediately Life Threatening.'
Conclusion
I would not, personally, recommend doing this.
But if you do, do so only in a very large and well ventilated space, stay several feet away from anyone while using it, and never spray for more than a few seconds at a time.
answered 23 hours ago
guildsbounty
31.1k5130155
15
For another example of people not realizing the dangers of simple asphyxiants, pouring liquid nitrogen in a pool creates a cool fog effect but can cause swimmers to pass out and fall into a pool and possibly drown.
– Captain Man
22 hours ago
3
Minor nit: CO2 does not cause asphyxiation by displacing oxygen, but rather by triggering respiratory spasms when atmospheric concentrations exceed blood concentration. This is why spacecraft and submarines need CO2 scrubbers in addition to an oxygen supply/generator.
– supercat
20 hours ago
4
@supercat It will, that's the point of a fire extinguisher. It does also act as a coolant, but the main point is for it to displace enough oxygen so fire doesn't spread. CO2 does indeed cause breathing problems in humans, but so does a lack of O2 caused by CO2 displacing it.
– Cubic
20 hours ago
8
@Cubic: According to OSHA, displacing 5-20% of the oxygen in a space will cause symptoms of hypoxia in someone engaged in physical exertion (presumably significantly faster at 20% than 10%). The CDC classifies a 10% concentration of CO2 is immediately life threatening. The concentration CO2 required to put out fires is sufficient to displace too much oxygen to sustain life, but CO2 can be rapidly fatal in concentrations below that.
– supercat
20 hours ago
4
@Malandy: No, because without the CO2 they wouldn't immediately pass out or start gasping for air; they would proceed into the room, start feeling weird, and eventually black out before realizing that there was no oxygen. Our bodies can't actually detect a lack of oxygen in the air, but they do detect excessive CO2.
– kundor
8 hours ago
 |Â
show 6 more comments
up vote
30
down vote
up vote
30
down vote
DISCLAIMER: I am not a medical or safety professional.
They can be very dangerous
I would not recommend doing this. CO2 Fire extinguishers present 2 basic hazards.
Cold Burns
Do Not Touch the horn (the part that sprays CO2) when spraying a CO2 Fire extinguisher. The horn of a CO2 fire extinguisher becomes extremely cold during use, and can cause cold burns if skin comes into contact with it.
Additionally, while the CO2 rapidly warms once it is clear of the extinguisher, it is very hazardous at close range. You are spraying rapidly-evaporating dry ice out of this thing, which will cause cold-burns.
They displace oxygen.
This is the greater risk. The way a CO2 Fire Extinguisher works is that it pushes all of the oxygen in an area away, replacing it with CO2, thereby smothering the fire. This is obviously a problem, because humans need to breathe oxygen.
Based off this, here are two safety pointers if you do decide to point one of these at a person.
- Only use in a large, extremely well-ventilated area. Ideally, outdoors. In a confined space, a CO2 Fire extinguisher can lower the oxygen content of the space far enough to cause asphyxiation
- Do not sustain the spray for more than a few seconds at a time. Even in a well-ventilated area, the space that the extinguisher is spraying will quickly have too little oxygen to sustain a person. Sustained spraying can suffocate a person.
IMPORTANT: The CO2 continues traveling even after it is no longer visible as a cloud. Just because you can't see that you're spraying someone or something doesn't mean you aren't.
As an addition (with thanks to @supercat), CO2 is hazardous on its own, even in concentrations less than those required to leave a person hypoxic. If at any point, the air reaches a 10% concentration of CO2 or greater, the CDC qualifies that as 'Immediately Life Threatening.'
Conclusion
I would not, personally, recommend doing this.
But if you do, do so only in a very large and well ventilated space, stay several feet away from anyone while using it, and never spray for more than a few seconds at a time.
answered 23 hours ago
guildsbounty
31.1k5130155
DISCLAIMER: I am not a medical or safety professional.
They can be very dangerous
I would not recommend doing this. CO2 Fire extinguishers present 2 basic hazards.
Cold Burns
Do Not Touch the horn (the part that sprays CO2) when spraying a CO2 Fire extinguisher. The horn of a CO2 fire extinguisher becomes extremely cold during use, and can cause cold burns if skin comes into contact with it.
Additionally, while the CO2 rapidly warms once it is clear of the extinguisher, it is very hazardous at close range. You are spraying rapidly-evaporating dry ice out of this thing, which will cause cold-burns.
They displace oxygen.
This is the greater risk. The way a CO2 Fire Extinguisher works is that it pushes all of the oxygen in an area away, replacing it with CO2, thereby smothering the fire. This is obviously a problem, because humans need to breathe oxygen.
Based off this, here are two safety pointers if you do decide to point one of these at a person.
- Only use in a large, extremely well-ventilated area. Ideally, outdoors. In a confined space, a CO2 Fire extinguisher can lower the oxygen content of the space far enough to cause asphyxiation
- Do not sustain the spray for more than a few seconds at a time. Even in a well-ventilated area, the space that the extinguisher is spraying will quickly have too little oxygen to sustain a person. Sustained spraying can suffocate a person.
IMPORTANT: The CO2 continues traveling even after it is no longer visible as a cloud. Just because you can't see that you're spraying someone or something doesn't mean you aren't.
As an addition (with thanks to @supercat), CO2 is hazardous on its own, even in concentrations less than those required to leave a person hypoxic. If at any point, the air reaches a 10% concentration of CO2 or greater, the CDC qualifies that as 'Immediately Life Threatening.'
Conclusion
I would not, personally, recommend doing this.
But if you do, do so only in a very large and well ventilated space, stay several feet away from anyone while using it, and never spray for more than a few seconds at a time.
answered 23 hours ago
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edited 19 hours ago
answered 23 hours ago
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answered 23 hours ago
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answered 23 hours ago
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15
For another example of people not realizing the dangers of simple asphyxiants, pouring liquid nitrogen in a pool creates a cool fog effect but can cause swimmers to pass out and fall into a pool and possibly drown.
– Captain Man
22 hours ago
3
Minor nit: CO2 does not cause asphyxiation by displacing oxygen, but rather by triggering respiratory spasms when atmospheric concentrations exceed blood concentration. This is why spacecraft and submarines need CO2 scrubbers in addition to an oxygen supply/generator.
– supercat
20 hours ago
4
@supercat It will, that's the point of a fire extinguisher. It does also act as a coolant, but the main point is for it to displace enough oxygen so fire doesn't spread. CO2 does indeed cause breathing problems in humans, but so does a lack of O2 caused by CO2 displacing it.
– Cubic
20 hours ago
8
@Cubic: According to OSHA, displacing 5-20% of the oxygen in a space will cause symptoms of hypoxia in someone engaged in physical exertion (presumably significantly faster at 20% than 10%). The CDC classifies a 10% concentration of CO2 is immediately life threatening. The concentration CO2 required to put out fires is sufficient to displace too much oxygen to sustain life, but CO2 can be rapidly fatal in concentrations below that.
– supercat
20 hours ago
4
@Malandy: No, because without the CO2 they wouldn't immediately pass out or start gasping for air; they would proceed into the room, start feeling weird, and eventually black out before realizing that there was no oxygen. Our bodies can't actually detect a lack of oxygen in the air, but they do detect excessive CO2.
– kundor
8 hours ago
 |Â
show 6 more comments
15
For another example of people not realizing the dangers of simple asphyxiants, pouring liquid nitrogen in a pool creates a cool fog effect but can cause swimmers to pass out and fall into a pool and possibly drown.
– Captain Man
22 hours ago
3
Minor nit: CO2 does not cause asphyxiation by displacing oxygen, but rather by triggering respiratory spasms when atmospheric concentrations exceed blood concentration. This is why spacecraft and submarines need CO2 scrubbers in addition to an oxygen supply/generator.
– supercat
20 hours ago
4
@supercat It will, that's the point of a fire extinguisher. It does also act as a coolant, but the main point is for it to displace enough oxygen so fire doesn't spread. CO2 does indeed cause breathing problems in humans, but so does a lack of O2 caused by CO2 displacing it.
– Cubic
20 hours ago
8
@Cubic: According to OSHA, displacing 5-20% of the oxygen in a space will cause symptoms of hypoxia in someone engaged in physical exertion (presumably significantly faster at 20% than 10%). The CDC classifies a 10% concentration of CO2 is immediately life threatening. The concentration CO2 required to put out fires is sufficient to displace too much oxygen to sustain life, but CO2 can be rapidly fatal in concentrations below that.
– supercat
20 hours ago
4
@Malandy: No, because without the CO2 they wouldn't immediately pass out or start gasping for air; they would proceed into the room, start feeling weird, and eventually black out before realizing that there was no oxygen. Our bodies can't actually detect a lack of oxygen in the air, but they do detect excessive CO2.
– kundor
8 hours ago
15
15
For another example of people not realizing the dangers of simple asphyxiants, pouring liquid nitrogen in a pool creates a cool fog effect but can cause swimmers to pass out and fall into a pool and possibly drown.
– Captain Man
22 hours ago
For another example of people not realizing the dangers of simple asphyxiants, pouring liquid nitrogen in a pool creates a cool fog effect but can cause swimmers to pass out and fall into a pool and possibly drown.
– Captain Man
22 hours ago
3
3
Minor nit: CO2 does not cause asphyxiation by displacing oxygen, but rather by triggering respiratory spasms when atmospheric concentrations exceed blood concentration. This is why spacecraft and submarines need CO2 scrubbers in addition to an oxygen supply/generator.
– supercat
20 hours ago
Minor nit: CO2 does not cause asphyxiation by displacing oxygen, but rather by triggering respiratory spasms when atmospheric concentrations exceed blood concentration. This is why spacecraft and submarines need CO2 scrubbers in addition to an oxygen supply/generator.
– supercat
20 hours ago
4
4
@supercat It will, that's the point of a fire extinguisher. It does also act as a coolant, but the main point is for it to displace enough oxygen so fire doesn't spread. CO2 does indeed cause breathing problems in humans, but so does a lack of O2 caused by CO2 displacing it.
– Cubic
20 hours ago
@supercat It will, that's the point of a fire extinguisher. It does also act as a coolant, but the main point is for it to displace enough oxygen so fire doesn't spread. CO2 does indeed cause breathing problems in humans, but so does a lack of O2 caused by CO2 displacing it.
– Cubic
20 hours ago
8
8
@Cubic: According to OSHA, displacing 5-20% of the oxygen in a space will cause symptoms of hypoxia in someone engaged in physical exertion (presumably significantly faster at 20% than 10%). The CDC classifies a 10% concentration of CO2 is immediately life threatening. The concentration CO2 required to put out fires is sufficient to displace too much oxygen to sustain life, but CO2 can be rapidly fatal in concentrations below that.
– supercat
20 hours ago
@Cubic: According to OSHA, displacing 5-20% of the oxygen in a space will cause symptoms of hypoxia in someone engaged in physical exertion (presumably significantly faster at 20% than 10%). The CDC classifies a 10% concentration of CO2 is immediately life threatening. The concentration CO2 required to put out fires is sufficient to displace too much oxygen to sustain life, but CO2 can be rapidly fatal in concentrations below that.
– supercat
20 hours ago
4
4
@Malandy: No, because without the CO2 they wouldn't immediately pass out or start gasping for air; they would proceed into the room, start feeling weird, and eventually black out before realizing that there was no oxygen. Our bodies can't actually detect a lack of oxygen in the air, but they do detect excessive CO2.
– kundor
8 hours ago
@Malandy: No, because without the CO2 they wouldn't immediately pass out or start gasping for air; they would proceed into the room, start feeling weird, and eventually black out before realizing that there was no oxygen. Our bodies can't actually detect a lack of oxygen in the air, but they do detect excessive CO2.
– kundor
8 hours ago
 |Â
show 6 more comments
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69
CO2 is very much not "just compressed air".
– T.J.L.
23 hours ago
4
Are you doing this indoors or outdoors?
– thosphor
21 hours ago
8
CO2 isn't just an oxygen displacer, humans are also allergic to it. That "OMG must breathe" sensation you get when you are not breathing, is not a lack of oxygen... actually there's still plenty of oxygen. That feeling is caused by the buildup of CO2 in not particularly high concentrations. It serves as a substitute for an oxygen density detector, which would've been evolutionarily harder to evolve.
– Harper
17 hours ago
3
flashlights make a cone... use that
– RedOculus
16 hours ago
10
@Harper "Allergic" isn't really the right term - it's not an immune system response or anything, or even an evolved response. It's the buildup of carbonic acid, which forms when there's a bunch of CO2 dissolved in water.
– Delioth
15 hours ago