# O2 Tanks In Cold.



## TornWingedAngel1 (Dec 30, 2009)

Maybe this is a silly question, or maybe it’s been answered for me before and I just simply can’t remember, but google searchs aren’t porving too helpful thus far.

But what are the effects of leaving O2 in the cold?  Like, inside a cold car, let’s say.  

The company I currently work for we park our rigs inside the garage at the end of the night.  O2 stays in the rigs, but the rigs are inside.  The company I worked for in Detroit, we were to turn into our O2 D tanks at the end of our shift.  (Though I’m not sure if that was for a safety issue or security purposes.)

What, if any, are the effects of cold weather on O2 tanks?  I mean, usually the rig’s main O2 tanks at my Detroit company’s was in the cold all the time (not garage, stationed outside) but I was just wondering…


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## medichopeful (Dec 30, 2009)

Matt.R.Costa said:


> Maybe this is a silly question, or maybe it’s been answered for me before and I just simply can’t remember, but google searchs aren’t porving too helpful thus far.
> 
> But what are the effects of leaving O2 in the cold?  Like, inside a cold car, let’s say.
> 
> ...



As far as I know, the only major thing would be that it could decrease the pressure in the tanks due to the decrease in movement of the molecules.  I can't think of the exact term for this right now (I want to say entropy but I'm pretty sure that's incorrect).  Of course, once the O2 warms back up the pressure would increase back to what it was (or around there).

The metal of the tanks could also potentially be weakened, but it would have to be REALLY cold.

The oxygen inside would be cold, which could be uncomfortable for the patient if it's used before being warmed back up.

I hope this helps.
Eric


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## ZVNEMT (Dec 30, 2009)

i think if there would be any problems due to leaving the tanks in the cold, they would have been addressed in the previous winters you company has experienced.


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## MMiz (Dec 30, 2009)

There is no problem storing oxygen tanks in the cold.  I worked for a private provider in Michigan that regularly stored oxygen tanks in the rigs that we left outside in winter.

Oxygen suppliers often store and transport tanks outside in cold conditions.  Looking at the NFPA and FDA, both say that outside storage is fine, as long as it's away from combustibles.

Of course I'm not a lawyer, nor an expert on oxygen.


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## lightsandsirens5 (Dec 30, 2009)

medichopeful said:


> As far as I know, the only major thing would be that it could decrease the pressure in the tanks due to the decrease in movement of the molecules. I can't think of the exact term for this right now (I want to say entropy but I'm pretty sure that's incorrect). Of course, once the O2 warms back up the pressure would increase back to what it was (or around there).
> 
> The metal of the tanks could also potentially be weakened, but it would have to be REALLY cold.
> 
> The oxygen inside would be cold, which could be uncomfortable for the patient if it's used before being warmed back up.


 
You are thinking of the Combined Gas Law (A combination of Boyle's law, Charles' law, and Gay-Lussac's law.) Where P1V1/T1=P2V2/T2

The Ideal Gas Law can also be applied I beleive. pV=nRT

(Look them up. I know them, but not well enough to explain here.)

I like the REALLY cold part. ^_^ That would be like liquid O2 type cold! (minus 200???)

And Your last one brings up an interesting point. I beleive that the temp. of the O2 might be the same no matter what the temp is outside. It is because when you release a presurized gas, it cools. (Quite a bit.) I am trying to figure that out right now, but I don't know how to quantify volume for a gas that has been released from a container into the atmosphere. If I figure it out, I'll let you know.


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## medicdan (Dec 30, 2009)

Boyle's law, as discussed above applies. The more important question, in my mind is why trucks are being left outside overnight. At least in MA, where is certainly gets cold, OEMS requires all ambulance-certified vehicles to be warm-garaged at all times when not occupied. Waivers can be obtained, but only for non-transport vehicles, and in that case, they need a "Winter Mode" that turns the engine on for a pre-determined amount of time every hour.

The worry about a cold (and ungaraged) vehicle is more about patient care and mechanics. As I understand, diesel engines (which are required for ambulances) are good at idleing for time, but cannot start cold (thus the need for engine block heaters, which, of course, are no good in the absence of a shore line). Keeping the engine (and passenger compartment) warm ensures that when you need to start the vehicle, you don't have a problem, and the patient can be comfortable. 

Lastly, ambulances tend to carry equipment and supplies that are temperature sensitive. Everything from Epi pens to AEDs, suction batteries, and sterile water, are all negatively  effected by extreme (and cold) temperatures. Oxygen cylinders are the least of your worries. 

Reconsider whether what your company is doing is legal in your region, or whether there is (could) be damage to the contents of the vehicle. Again, I dont think there is a problem with a vehicle being in an unheated garage (as long as there is a shore line, with engine block heater), temperatures never approach freezing, and medications are taken out of the vehicle.

Good Luck!


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## DV_EMT (Dec 30, 2009)

Cold = Contracting molecules

Hot = Expanding molecules

in a nutshell - unless it's hot out... don't worry bout the tanks!


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## medicdan (Dec 31, 2009)

yes, with cold, you are going to have less pressure, not more. That is, of course, why when you fill a bottle it gets warm. Many dive shops, in order to maximally fill their tanks (and knowing they will be out of the sun), fill their tanks in a bath of water.


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## Foxbat (Dec 31, 2009)

lightsandsirens5 said:


> And Your last one brings up an interesting point. I beleive that the temp. of the O2 might be the same no matter what the temp is outside.


These are two different things. Temperature of O2 in the tank is the same as the temperature of the environment it is in (after it has been there for a long time) and it further cools down upon expansion.
As of how to quantify the drop in temperature after expansion, I suspect there are many factors in this, such as at what velocity and flow rate O2 escapes the cylinder; furthermore, it's a transient process and the temperature of escaping O2 will probably vary in time.


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## lightsandsirens5 (Dec 31, 2009)

Foxbat said:


> These are two different things. Temperature of O2 in the tank is the same as the temperature of the environment it is in (after it has been there for a long time) and it further cools down upon expansion.
> As of how to quantify the drop in temperature after expansion, I suspect there are many factors in this, such as at what velocity and flow rate O2 escapes the cylinder; furthermore, it's a transient process and the temperature of escaping O2 will probably vary in time.


 
Ahhhh....yes O Knowledgable One. However, this lowly EMT was refering to the temp to which the O2 is cooled upon release.

Since once the gas is released into the atmosphere, the volume can increase infinatly (almost), then the pressure would decrease infinatly (again, almost). Thus my thinking was: With this direct inverse variation between volume and pressure, temp. must remain constant.B)










(Now that I say that it sounds incorrect.:blush: I must go dig my physcis textbook up. Later peoples.)


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## KB1MZR (Dec 31, 2009)

As far as I know there is nothing against the oxygen left in the cold. CT OEMS requires all certified vehicles to be left in 60 degree or higher temperature so if we have to leave a vehicle outside it needs to be kept at a constant 60 using heaters etc.  But, for my POV i leave oxygen in my car 24/7 in the winter and what I do is keep a couple of hot packs in my oxygen bag and if the oxygen were that cold I would just wrap a hot pack around some oxygen tubing, just make sure its not hot o2 for ur patient.


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## RescueYou (Dec 31, 2009)

No problems that I know of. Prolonged exposure may cause decreased pressure, but it shouldn't have a big effect. Heat on the other hand....


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## usalsfyre (Dec 31, 2009)

No problems with the average tempature variations. We have outside storage for our spare tanks and have tempature variation from about 20 to 115 degrees throughout the year and don't have a problem. Your drugs on the other hand...


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## WarDance (Dec 31, 2009)

The major concern is the metal tank in the cold but I don't think that will be an issue in your area.  The area I live does get cold enough for this to be an issue.....

However, as mentioned before, the drugs should be the main concern.  Too hot or too cold is no good.


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## Foxbat (Dec 31, 2009)

lightsandsirens5 said:


> Ahhhh....yes O Knowledgable One. However, this lowly EMT was refering to the temp to which the O2 is cooled upon release.


Sorry if I sounded arrogant or something, it wasn't the intent. I still think it's impossible to get it from just PV=nRT.


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## silver (Dec 31, 2009)

You need to modify the ideal gas law a lot. Not for the faint of heart.
http://en.wikipedia.org/wiki/Joule–Thomson_effect

The only worries would be failures of rubber O rings on regulators and valves. Also don't fill your tank in cold cold temperatures.


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## TornWingedAngel1 (Jan 3, 2010)

Heh, I'm glad to see a thread filled with such input.



KB1MZR said:


> As far as I know there is nothing against the oxygen left in the cold. CT OEMS requires all certified vehicles to be left in 60 degree or higher temperature so if we have to leave a vehicle outside it needs to be kept at a constant 60 using heaters etc.  But, for my POV i leave oxygen in my car 24/7 in the winter and what I do is keep a couple of hot packs in my oxygen bag and if the oxygen were that cold I would just wrap a hot pack around some oxygen tubing, just make sure its not hot o2 for ur patient.



This is why I'm asking.  I just recently bought an O2 tank and wanna make sure I can keep it stored in my car.  I live in the Chiago-area, so it can get pretty damn cold in the winter.

The hot pack idea is a good, idea, and I'll do that.  I just wanted to make sure there were no dangers from leaving it in my car in the midwest cold.  (Or heat, I guess, but that's not as big of an issue in the midwest, I'd think.)


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## medichopeful (Jan 3, 2010)

Matt.R.Costa said:


> Heh, I'm glad to see a thread filled with such input.
> 
> 
> 
> ...



May I ask why you bought an O2 tank?


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## medicdan (Jan 3, 2010)

KB1MZR said:


> As far as I know there is nothing against the oxygen left in the cold. CT OEMS requires all certified vehicles to be left in 60 degree or higher temperature so if we have to leave a vehicle outside it needs to be kept at a constant 60 using heaters etc.  But, for my POV i leave oxygen in my car 24/7 in the winter and what I do is keep a couple of hot packs in my oxygen bag and if the oxygen were that cold I would just wrap a hot pack around some oxygen tubing, just make sure its not hot o2 for ur patient.



I remember reading somewhere... and I will look up where... that trying to head O2 that way just doesnt work. Oxygen (and other noble gases) dont have a high enough specific heat capacity, so even if you warmed it up significantly at or near the bottle, if the environment is cold, it's all lost along the way in the tubing. 
Saline and other fluids, OTOH, may benefit from being warmed before a call (thus the commercial warmers), because they hold temperature more efficiently (specific heat capacity).

EDIT: C/O Wikipedia, some numbers:
Oxygen (at 25c/77f) has a heat capacity of 0.918 Joules /(Grams*Kelvin)
Water (and other minerals inside) (at 25c) has a heat capacity of 4.1813 J/(g*K)

Thus, Water holds a temperature roughly four times as well as oxygen ( at 77*f), or oxygen looses heat four times as fast as water. Does this make sense?


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## JPINFV (Jan 3, 2010)

emt.dan said:


> Oxygen (and other noble gases)



Oxygen is not a noble gas.


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## medicdan (Jan 3, 2010)

And THAT would be why I am not a science major. FAIL. apologies.


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## lightsandsirens5 (Jan 4, 2010)

Foxbat said:


> Sorry if I sounded arrogant or something, it wasn't the intent. I still think it's impossible to get it from just PV=nRT.


 
Not at all! It was a joke. I think you're right anyhow.


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## Scout (Jan 4, 2010)

Whats cold?

And TBH I'd worry about other stuff before O2 became a concern. Drugs Engine etc....


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## redcrossemt (Jan 4, 2010)

emt.dan said:


> And THAT would be why I am not a science major. FAIL. apologies.



LOL!

You can't really heat oxygen easily in any useful way, but you can definitely heat an oxygen-enriched air mix usefully by keeping it humidified and warming the water there. The Res-Q-Air is one such product that does that... I've seen it used for Wilderness SAR transport. The air that comes out of it is definitely humidified and warm. (It's not really practical outside of a vehicle, though.)

Regarding storage of trucks outside, it's fairly common here in Metro Detroit. Our remote station based (primary 911) trucks are parked inside at stations. Our 12-hour trucks are parked under an awning with shore power for a block heater and battery charger. Our medications, IV fluids, etc. are taken inside at the end of each shift. I know that many companies also use their rear compartment heaters and leave all of the equipment in the truck.


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## Foxbat (Jan 4, 2010)

lightsandsirens5 said:


> Not at all! It was a joke. I think you're right anyhow.


No problem.


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## TornWingedAngel1 (Jan 4, 2010)

<I>May I ask why you bought an O2 tank?</I>

It was cheap, LOL.

But what got me looking for one in the first place was I was on my way home from best buy and there was apparently an accident.  In most cases, I don’t stop, unless someone is seriously hurt.  (I mean, come on, 911 will be there in a few minutes.)  But this one I did.

There was a small kid in the middle of the road, apparently hit by a car, with a pool of blood under him, coming seemingly from his head.

An off-duty nurse pulled over with me.  He had his ABCs, but wouldn’t ackowledge us in the slightest.  Just groaned.  So we basically could only control bleeding and hold Cspine.

Normally I have some medical stuff in my car, but I recently took it out to inventory it.  And I kept thinking of things I could do.  I went on ebay to find jump bags (I’d been planning on doing this anyway, the event just encouraged me to do it that day) and I saw an O2 tank.  Had I had that, I coulda’ popped the kid on some O2.

Had it not been a kid, I probably wouldn’t have taken it as seriously.  He couldn’t have been more than 9…10 at the most.  (I have a soft spot for kids.)  So I almost didn’t get it.  I was like “When am I ever gonna really need it?”  which I answered with “On days like today?”  I wasn’t gonna drop a whole bunch of money on it, but it was less than fifty bucks…so…


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## medichopeful (Jan 5, 2010)

Matt.R.Costa said:


> <I>May I ask why you bought an O2 tank?</I>
> 
> It was cheap, LOL.
> 
> ...



Though what you did was definitely admirable, you need to make sure that you know about the laws in your area.  Keep in mind that oxygen, though it may not seem like it, is a drug.  And if you are giving a drug while not attached to a service, you could have some legal issues.  And remember, you should put the same effort into both adults and children.

Also, just make sure to keep yourself safe out there.  Don't get injured or killed because you stopped at an accident scene.


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## TornWingedAngel1 (Jan 5, 2010)

<I>Though what you did was definitely admirable, you need to make sure that you know about the laws in your area.</I>

Going through all the proper channels.  =P

<I>And remember, you should put the same effort into both adults and children.</I>

I do.  And, to be fair, if it was an adult in that situation I probably would have still stopped.  But that was my first legit peds trauma, so it kinda’ stuck with me.  I don’t treat kids different than adults, but they effect me differently.  (Which, to my understanding, is pretty common.)

<I>Also, just make sure to keep yourself safe out there. Don't get injured or killed because you stopped at an accident scene.</I>

Oh, always.  First rule; scene safety.  =P  I used my POV on an angle to block the scene as best I could (considering it’s only a mustang) and moved it when I heard the sirens coming close to the rig to park there.


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## MedicSqrl (Jan 6, 2010)

In FL, we keep them outside too. Although it get so cold here we have to warm them up by the fire to make sure their ready...lol


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## VentMedic (Jan 6, 2010)

Matt.R.Costa said:


> <Oh, always. First rule; scene safety. =P I used my POV on an angle to block the scene as best I could (considering it’s only a mustang) and moved it when I heard the sirens coming close to the rig to park there.


 
You have now created more obstruction in the road that can cause another MVC and death.   If you were on duty and some lay person had done that you would probably be screaming at the top  of your lungs at what an idiot they are.    

http://firefighterclosecalls.com/fullstory.php?98816




> I>May I ask why you bought an O2 tank?</I>
> 
> It was cheap, LOL.


 
Has this tank been inspected? Do you have records for it?  Did it previously contain medical grade gas?  Or, was it a welding tank or one at some O2 bar?  Does it have a fixed liter flow?   Do you have a written protocol from your medical director or sponsoring agency to administer O2?   

Where did you buy your O2 tank? EBay?  Used or New?   If used and from some place like Ebay, what are the chances this is stolen property?


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## TornWingedAngel1 (Jan 6, 2010)

<I>You have now created more obstruction in the road that can cause another MVC and death. If you were on duty and some lay person had done that you would probably be screaming at the top of your lungs at what an idiot they are.</I>

Nah.  It wasn’t blatantly in the middle of the road.  Kind of angled.  Along with the other four cars that pulled aside, LOL.  Weather conditions were fine.  No fog, no icy roads, no rain.  Just dry cold.

Basically the scene was almost boxed in.  I park my car in toward the scene, with the tail end sticking out, so the one part that was open wasn’t anymore.  I know that’s not a very good explanation, as it’s hard to explain.  There was also an on-duty police officer helping to direct traffic and control the scene while me and the off-duty nurse tended to the pt.

<I>Has this tank been inspected? Do you have records for it? Did it previously contain medical grade gas? Or, was it a welding tank or one at some O2 bar? Does it have a fixed liter flow? Do you have a written protocol from your medical director or sponsoring agency to administer O2? 

Where did you buy your O2 tank? EBay? Used or New? If used and from some place like Ebay, what are the chances this is stolen property?</I>

Yes to most of that.  It was a brand-new tank with proper liter flow from a medical supply store.

Like I said, I’m going through all the proper channels for it, haha.


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## 18G (Jan 6, 2010)

I own my own O2 bottle. I bought in new from Galls many years ago. It came in handy a few times. I've left my O2 bottle in the trunk many winters and have not noticed any problems with it. 

My only concern is what the extreme cold may do to the metal in the regulator over time. Will it cause some calibration issues with proper liter flow? I'm not sure. I no longer keep it in my vehicle anymore, however.


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## medicdan (Jan 6, 2010)

18G said:


> I own my own O2 bottle. I bought in new from Galls many years ago. It came in handy a few times. I've left my O2 bottle in the trunk many winters and have not noticed any problems with it.
> 
> My only concern is what the extreme cold may do to the metal in the regulator over time. Will it cause some calibration issues with proper liter flow? I'm not sure. I no longer keep it in my vehicle anymore, however.



If you're concerned about the metal, make sure your bottle gets a hydrostatic test every 3/5 years, as required.


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## 18G (Jan 6, 2010)

Im not worried about the bottle.. Im worried about the regulator. They don't hydro test regulators.


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## medicdan (Jan 6, 2010)

No, but they function test them. Just about any dive shop, or whoever does the hydro can do a functional test on the regulator-- essentially measuring the literflow output. 

Ultimately, as long as your maintain your seals/o-rings (remember, never with petroleum based lubrication), the effects of metal fatigue on the first (and second) stage should be minimal.


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## VentMedic (Jan 6, 2010)

emt.dan said:


> No, but they function test them. Just about any dive shop, or whoever does the hydro can do a functional test on the regulator-- essentially measuring the literflow output.


 
But if they are bypassing the proper channels to get tanks filled at other than a medical gas place and then holding it out to be medicinal quality, they are going to be in a deep mess and more than just their cert will be at stake.


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## 18G (Jan 6, 2010)

Why would you think anyone would buy an oxygen bottle and even consider getting it filled with anything other than medical grade O2? I've filled mine with the O2 cascade system at the department I used to work and have taken it to a place that deals strictly with medical oxygen supply.


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## VentMedic (Jan 6, 2010)

18G said:


> Why would you think anyone would buy an oxygen bottle and even consider getting it filled with anything other than medical grade O2? I've filled mine with the O2 cascade system at the department I *used to work* and have taken it to a place that deals strictly with medical oxygen supply.


 
Many people don't know the definition or the requirements of medical grade O2.

You have it in writing that the medical director of the department you used to work for allows you to administer O2 while off duty to whomever you feel like it? How do you document that? 

Is your department keeping records and will they be responsible for your tank if something happens to you or the patient? 

If this was actually legit, you wouldn't be filling your tank at a department that you *used to work* for.


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