Exploding CO2

[bcroslin]

It never occurred to me that a CO2 might explode in a hot car but apparently it happened to someone I ride with:

https://www.instagram.com/p/BF1UANRu9f7/

Wow.

[11.4]

The temperature change isn't enough to expand the gas to such a degree that it should blow. This was a defective cartridge or frankly, most likely, something else entirely. I wouldn't be worrying about it.

[cookietom]

The temperature change isn't enough to expand the gas to such a degree that it should blow. This was a defective cartridge or frankly, most likely, something else entirely. I wouldn't be worrying about it.

I agreed:cool:

[bcroslin]

The temperature change isn't enough to expand the gas to such a degree that it should blow. This was a defective cartridge or frankly, most likely, something else entirely. I wouldn't be worrying about it.

A car with the windows up in sunny FL can exceed 150 degrees. What else entirely might it have been? He clearly has a CO2 that exploded.

[benb]

I've seen 150+ in my car (in New England, not Florida) thanks to having a bike computer that had a temp gauge back when I had a black Acura RSX with a black leather interior. I would have to deflate my tires and stuff. I should have gotten the hatch + rear windows tinted.

Another reason CO2 is silly compared to a pump, even if this was kind of a fluke thing just helped along by the high temps.

[azrider]

Not much of a bikesensei I'd say :D;)

[Steve in SLO]

Good thing that didn't happen his jersey pocket!

[rustychisel]

Good thing that didn't happen his jersey pocket!

Oh, come on, scare mongering. Of course it might get hot enough in concentrated conditions in a hot car, but if it ever got hot enough in a jersey pocket the wearer would have greater dangers to deal with - like cooking from the inside out, slowly.

When I was a kid we used to used expended CO2 cartridges as home made RPGs using .22 propellant and match heads. Ah, those far off heady dangerous days...

[Steve in SLO]

Hey Rusty, I was not consciously scaremongering, rather was musing during my pre-coffee sleep-deprived state. CO2 cartridges don't scare me. What did scare me was seeing their big brother, a fully pressurized scuba tank, break off its valve and go for a trip through a scuba shop wall.

[OtayBW]

Vapor pressure of CO2 will >triple from ~50°F to 150°F. Don't know if that is sufficient to blow the cartridge, but that seems substantial....:eek:

[malcolm]

I leave them in my car in Alabama all the time time and have yet to have one blow. I may have to reconsider it now.

[cookietom]

If you put at least three Co2 in end of saddle bag, and you will get a free long ride when they exploded on hot day.

Tom

Always think safety first.

[verticaldoug]

If you read on the box there is a warning around 120 F (50 C) for storing. I 'd call this a rupture and fly off somewhere while not fully exploding... In the video, I'd call that a rupture.


air gun manufacturers have warnings on storage.

[Black Dog]

If you read on the box there is a warning around 120 F (50 C) for storing. I 'd call this a rupture and fly off somewhere while not fully exploding... In the video, I'd call that a rupture.


air gun manufacturers have warnings on storage.


There is a large safety margin built into that warning. 50 C is the temp at which it will fail, not even close.

[11.4]

The gas laws are calculated based on degrees Kelvin. That's centigrade plus 273. So if you are at 70 degrees Fahrenheit, you are at roughly 293 degrees Kelvin. If you are at 212 degrees Fahrenheit, you are at 373 degrees Kelvin. That's actually a 27% increase in gas pressure. No tripling or anything like that.

[rustychisel]

Hey Rusty, I was not consciously scaremongering, rather was musing during my pre-coffee sleep-deprived state. CO2 cartridges don't scare me. What did scare me was seeing their big brother, a fully pressurized scuba tank, break off its valve and go for a trip through a scuba shop wall.

I know, mate. Just saying, you know? [whilst watching the Giro late last night] :beer:

[foo_fighter]

Is it liquid or gas inside the cartridge?

The gas laws are calculated based on degrees Kelvin. That's centigrade plus 273. So if you are at 70 degrees Fahrenheit, you are at roughly 293 degrees Kelvin. If you are at 212 degrees Fahrenheit, you are at 373 degrees Kelvin. That's actually a 27% increase in gas pressure. No tripling or anything like that.

[Black Dog]

Is it liquid or gas inside the cartridge?

Liquid.

[11.4]

Gaseous. Liquid CO2 is extremely cold and goes through a phase transformation to become solid (known as "dry ice"). But it isn't stable at room temperature in those states. To maintain pressure it would have to remain gaseous, because it couldn't transform to gaseous phase fast enough to do what it does when inflating a tire.

[Black Dog]

Gaseous. Liquid CO2 is extremely cold and goes through a phase transformation to become solid (known as "dry ice"). But it isn't stable at room temperature in those states. To maintain pressure it would have to remain gaseous, because it couldn't transform to gaseous phase fast enough to do what it does when inflating a tire.

Well it is really both in a state of equilibrium.

[Tony T]

Come on, this is very easy to test.
Someone, anyone, just put a C02 in your oven, and let us know at what temp it explodes. ;)

[Louis]

Belichick did it.

[OtayBW]

The gas laws are calculated based on degrees Kelvin. That's centigrade plus 273. So if you are at 70 degrees Fahrenheit, you are at roughly 293 degrees Kelvin. If you are at 212 degrees Fahrenheit, you are at 373 degrees Kelvin. That's actually a 27% increase in gas pressure. No tripling or anything like that.Please forgive me if I'm mistaken, but my understanding is that the fundamental relationship between vapor pressure of a gas and temperature does not change as a function of the units of measure. The only difference between vapor pressure (at a fixed unit of measure) and temperature - whether it is reported in °C, °F, or K - should be the slope of the curves which I suspect could account for the relative difference that you're talking about. Kelvin has the lower slope - e.g., over the temperature range of 0°C to 100°C, the Farenheight scale increases from 32°F to 212°F (180 degrees) while K only increases from 273K to 373K (100 degrees).

In this case, we were talking about the effects of car dashboard temps of ~150°F, so that's what I used in the conversion. Cheers.

[11.4]

Please forgive me if I'm mistaken, but my understanding is that the fundamental relationship between vapor pressure of a gas and temperature does not change as a function of the units of measure. The only difference between vapor pressure (at a fixed unit of measure) and temperature - whether it is reported in °C, °F, or K - should be the slope of the curves which I suspect could account for the relative difference that you're talking about. Kelvin has the lower slope - e.g., over the temperature range of 0°C to 100°C, the Farenheight scale increases from 32°F to 212°F (180 degrees) while K only increases from 273K to 373K (100 degrees).

In this case, we were talking about the effects of car dashboard temps of ~150°F, so that's what I used in the conversion. Cheers.

The issue here is how much the internal pressure increases. Pressure is proportional to temperature, but temperature has to be measured in Kelvin. That has the effect of changing the slope of a plot of pressure versus temperature, but the basic relationship here is whether going from 50 to 150 degrees Fahrenheit triples the internal pressure. It doesn't. It only increases it about 25%. A tripling might explain an exploding CO2 cartridge. A 25% increase means that if the cartridge did explode (and I would have liked to have seen the cartridge shards rather than just the overall scene of an explosion), it had to do so because it was defective or damaged.

[cp43]

The issue here is how much the internal pressure increases. Pressure is proportional to temperature, but temperature has to be measured in Kelvin. That has the effect of changing the slope of a plot of pressure versus temperature, but the basic relationship here is whether going from 50 to 150 degrees Fahrenheit triples the internal pressure. It doesn't. It only increases it about 25%. A tripling might explain an exploding CO2 cartridge. A 25% increase means that if the cartridge did explode (and I would have liked to have seen the cartridge shards rather than just the overall scene of an explosion), it had to do so because it was defective or damaged.

About half way through the video (the link in the first post is a video, it's not obvious though) the guy shows the cartridge. There aren't shards, but it clearly failed.

[OtayBW]

No disrespect, but I’m not sure that I fully understand your rationale. The fundamental relationship between some physical parameter and temperature does not change whether you measure temp in °C, °F, or K any more than my weight changes if I use a scale that reports in lbs vs one that uses kg. My mass is the same no matter what scale or unit of measure is involved. Likewise, the physical property of a gas does not change whether you report e.g., P in terms of psi, mPa, kPa, atm, torr, or mg per sq. furlong for that matter. The relationship between gas vapor pressure and temperature is well-known and conversion between units is shown in many thousands of published papers on this and related topics.

http://i77.photobucket.com/albums/j42/zelmo_2006/VaporPressure3a.jpg (http://s77.photobucket.com/user/zelmo_2006/media/VaporPressure3a.jpg.html)

As an example: this representative data shows that for, say just the temperature range of ~50° to ~100°F, CO2 pressure nearly ~doubles with the trends increasing as temps increase further. My apologies if I'm missing something, so please feel free to have the last word on this because…. I’m out.

[11.4]

No disrespect, but I’m not sure that I fully understand your rationale. The fundamental relationship between some physical parameter and temperature does not change whether you measure temp in °C, °F, or K any more than my weight changes if I use a scale that reports in lbs vs one that uses kg. My mass is the same no matter what scale or unit of measure is involved. Likewise, the physical property of a gas does not change whether you report e.g., P in terms of psi, mPa, kPa, atm, torr, or mg per sq. furlong for that matter. The relationship between gas vapor pressure and temperature is well-known and conversion between units is shown in many thousands of published papers on this and related topics.

http://i77.photobucket.com/albums/j42/zelmo_2006/VaporPressure3a.jpg (http://s77.photobucket.com/user/zelmo_2006/media/VaporPressure3a.jpg.html)

As an example: this representative data shows that for, say just the temperature range of ~50° to ~100°F, CO2 pressure nearly ~doubles with the trends increasing as temps increase further. My apologies if I'm missing something, so please feel free to have the last word on this because…. I’m out.

The point I was trying to correct from someone else's post was one of magnitude: Because the gas laws maintain their relationship between temperature and pressure when degrees Kelvin are used, two temperatures, such as 50 and 100 F, are actually the ratio not of 50 to 100 but of 323 to 373. That ratio is also the ratio of the gas pressure at 50 versus 100. It isn't a doubling, but a small fractional increase. Gas pressure units are all measured from zero pressure. Volume units are all measured from zero volume. But temperature units are measured starting at different points for Kelvin, Fahrenheit, and Centigrade. That is what's missing in your analysis.

[cookietom]

Damn, just buy a small hand pump.

[MikeD]

The ideal gas law doesn't apply in this case. CO2 is liquid, not gas, in these cartridges.


Sent from my iPhone using Tapatalk

[11.4]

The nominal pressure for CO2 cartridges is 853 psi. You'll sometimes see them listed at 900 psi, though the pressure is quite variable due to manufacturing variances. At this pressure, at room temperature, the contents are close to the phase transition but are nearly all or completely gas. The contents have to be gas to exert pressure on the inside of the cartridge, and if you consider how fast a cartridge can fill a tube, it won't do so if it's full of liquid that has to undergo a phase transition from what would already, by your argument, be a stable state. There may, at certain temperatures, be some liquid CO2 in a cartridge, but as any pressure is released or as the cartridge warms up at all, it transitions to gaseous.

Inflating a bike tire is a relatively slow process and we want it to be. However, consider a pellet rifle or pistol powered by the same CO2 cartridge. It has to provide instantaneous pressure at a peak level if it's to propel a pellet. It can't do that if it's liquid. Liquids are generally incompressible and any pressure, whether upon release or simply pressure within the cartridge, is due to gaseous CO2 in the cartridge.

[11.4]

And by the way, TSA and airlines prohibit CO2 cartridges on airplanes not because they are prone to exploding, but because the cartridges are unregulated. Even your can of shaving cream has a pressure release valve on the bottom to compensate for manufacturing errors or whatever. CO2 cartridges don't and thus aren't subject to any kind of safety, transportation, or other regulation. An unregulated product isn't allowed on aircraft, period.

[redir]

Note to self...

[Mark McM]

And by the way, TSA and airlines prohibit CO2 cartridges on airplanes not because they are prone to exploding, but because the cartridges are unregulated. Even your can of shaving cream has a pressure release valve on the bottom to compensate for manufacturing errors or whatever. CO2 cartridges don't and thus aren't subject to any kind of safety, transportation, or other regulation. An unregulated product isn't allowed on aircraft, period.

Well, except for self-inflating life vests, which are under each and every airline seat. The TSA also allows passengers to bring up to two of their own self-inflating life vests plus two spare gas cartridges. Just make sure that the same cartridges that work with your life vest also work with your tire inflator, and you're all set.

https://www.tsa.gov/travel/security-screening/prohibited-items

[11.4]

Well, except for self-inflating life vests, which are under each and every airline seat. The TSA also allows passengers to bring up to two of their own self-inflating life vests plus two spare gas cartridges. Just make sure that the same cartridges that work with your life vest also work with your tire inflator, and you're all set.

https://www.tsa.gov/travel/security-screening/prohibited-items

Good point. It's like the prohibition on oxygen-generating canisters after the old Everglades ValuJet crash. All fine except that many jets use the very same canisters for emergency oxygen.

I would have to check but I believe the aircraft manufacturers have basically done away with inflating life vests, going with foam flotation instead. Some airlines like Air France use chemical pellet designs to generate CO2. And the inflatable vests I have for sailing use a low-powered cartridge -- it only has to inflate a small volume vest to a low pressure, nothing like filling a 100-125 psi tire.

[jemoryl]

I vote defective cartridge. A couple points:

Using the ideal gas law to figure out the pressure of gas in one of these cartridges is probably not appropriate, since I believe the CO2 exists as a liquid in equilibrium with some gas under the conditions (volume, moles of substance, temperature). So you would need to look a phase diagram for CO2 to figure out what would happen when you raise the temperature. I can't be bothered to look it up, but my hunch is that at any temperature compatible with human life, the pressure will not go so high as to explode the cartridge.

And if you are comparing the pressure of gas at two different temperatures, you do need to use Kelvin. As one should for all thermodynamic calculations.

[Tony T]

I vote defective cartridge. …

And there are probably many more "defective" cartridges sitting in saddle bags right now. No way to test if the cartridge is defective, so just don't leave them in a hot car, or do as I do — use a pump.

[MikeD]

The pressure in these cartridges is the vapor pressure of CO2 at the temperature it is at.


Sent from my iPhone using Tapatalk

[lonoeightysix]

Completely possible, could be overfilled from the factory, defective cartridge (these are not DOT pressure vessels/no safety relief or frangible disc). BTW, CO2 is filled by weight, same goes for CO2 extinguishers, industrial cylinders, paintball, etc. If you looked at a freshly filled CO2 cylinder with a thermal imaging camera, you'd see the liquid level (you see the frost line on a humid day).

Overfilled propane 20# will vent on a hot day in the sun, same pressurization principle, except in a DOT vessel with a relief valve.

[oldpotatoe]

About half way through the video (the link in the first post is a video, it's not obvious though) the guy shows the cartridge. There aren't shards, but it clearly failed.

But it is already punctured from the inflator..if you watch the part when he shows the end, has a wee hole in it(?)

[Climb01742]

Damn, fellas, why ya gotta make me feel like I'm back in all those high school science classes I didn't understand then...or now.:D;)

Always impressed by the collective and somewhat arcane knowledge bases resident here. Carry on!:beer:

[11.4]

But it is already punctured from the inflator..if you watch the part when he shows the end, has a wee hole in it(?)

I hadn't noticed that, but this is an important point. One of the most common failures with cartridges is at the junction with whatever fitting they are screwed into. That may have happened here too. Again, looks like a defective cartridge (or perhaps more properly, user error, with a stored cartridge that had already been punctured).

[Fatty]

Well that saddle bag sure came out worse for the wear.

How it's made, the co2 cartridge that is.

https://www.youtube.com/watch?v=tpIW2oX7rI0

[steveoz]

interesting that the seal that is punctured when you use an inflator is still intact - leads me to believe it was a defective canister...

[rustychisel]

Leads to a question of how long you should keep the things lying around. I have CO2 canisters here which might be 4,5,6 years or older. They go for a ride in my pocket then get put back in the ready use drawer until next time.

Thoughts?

[11.4]

Leads to a question of how long you should keep the things lying around. I have CO2 canisters here which might be 4,5,6 years or older. They go for a ride in my pocket then get put back in the ready use drawer until next time.

Thoughts?

There's no way to test, and there's a slight amount of loss in some cartridges due to microscopic defects in the seals. People who shoot target pellet pistols worry about that kind of thing. I don't buy too many canisters at a time, date them, and just make sure to use them.

Remember that CO2 is much more permeable through an inner tube anyway -- the air you pump into a butyl tube may lose 1-3 lbs a day but the CO2 from a canister will lose 10-15. It's just a smaller and more permeable molecule. So after you've changed a flat and filled the tire with CO2, remember to deflate it fully and refill with your foot pump before the next ride.

[rustychisel]

Remember that CO2 is much more permeable through an inner tube anyway -- remember to deflate it fully and refill with your foot pump before the next ride.

Yeah, I knew that. Point being, I almost never flat and don't remember the last time I used a CO2 canister.

Thanks

[LegendRider]

I had a cannister of Vittoria Pit Stop explode in my car. I unintentionally left it in the front seat while the car was parked in direct Georgia summer sunlight. (My first reaction upon seeing the mess was to think a raccoon got in the car!)

[Louis]

I had a cannister of Vittoria Pit Stop explode in my car. I unintentionally left it in the front seat while the car was parked in direct Georgia summer sunlight. (My first reaction upon seeing the mess was to think a raccoon got in the car!)

Interesting. Was there much shrapnel, or just a hole blown in the cartridge? What was the damage to the car? Or was it just a huge mess?

[LegendRider]

Interesting. Was there much shrapnel, or just a hole blown in the cartridge? What was the damage to the car? Or was it just a huge mess?

Hole in the cannister - no shrapnel - big mess - no damage to car.

[rustychisel]

Not that I've ever worried about it or considered it a possibility, but summer riding with a couple of these in your jersey pocket.

Down here I habitually ride when it's hot, damn hot. I've ridden on a 43º day, that's something over 110ºF. Not going to happen, but I'd not want one cooking off mid-ride.

[goonster]

Liquid CO2 is extremely cold

Well . . . that depends on the pressure. At 900 psia, CO2 is liquid at room temperature.

To maintain pressure it would have to remain gaseous, because it couldn't transform to gaseous phase fast enough to do what it does when inflating a tire.

Rate of the phase change will depend on the pressure gradient (and to a lesser degree, heat transfer rates). Vent the cartridge, and any liquid previously in equilibrium will flash almost instantaneously. In this scenario, the rate limiting factor would be size of orifice, not phase transfer of liquid portion.

[jemoryl]

.....It's just a smaller and more permeable molecule. So after you've changed a flat and filled the tire with CO2, remember to deflate it fully and refill with your foot pump before the next ride....

More permeable through rubber, but not smaller.

[11.4]

Actually, what we want to be looking at is the kinetic diameter of the gases. The kinetic diameter of carbon dioxide is 330 Angstroms, while that of nitrogen (the 80% component of air) is 364 Angstroms.

And as far as permeability goes, this is a complex phenomenon. It isn't just gas molecules seeping through nano-holes in the rubber. The phenomenon we're dealing with here involves the gas molecules partially dissolving in the colloid that is either latex or butyl rubber. In that case, matters such as reactivity and ionic potential come into play. These happen to be some of the same issues that determine kinetic diameter of the gases.

[11.4]

As for the liquid versus gaseous issue, the concern is about how gas cartridges will behave at elevated temperatures. The triple point for CO2 is 72.9 atm at 31 degrees Centigrade. And that's simply the ambient temperature on a hot day, before heating up in a car or elsewhere. That's well over 1000 psi, and the rated pressure on a cartridge is nominally 853 psi (a number specifically chosen to stay below the triple point at lower room temperatures). If the cartridge is heated to, say, 50 degrees Centigrade, the contents are completely gaseous.