Mounting a CO2 tank on the roof in direct sunlight

[NLXTACY]

Any issues with mounting the CO2 tank on the roofrack and leaving it there in the sun? I did it last year with no issues but I had a conversation with someone who says that the tanks are not designed to stay out in direct sunlight. Wanted to get your feedback.

 

[bigndn]

I'd find it hard to believe that a bottle designed to contain a liquid, that wants to be a gas and expands over 100X during that conversion, couldn't handle a little solar input. I don't think I'd set it in the middle of the campfire, though. ;p

 

[sirenmoses]

My feedback is "nope, don't worry about it".

I said something similar about compressed air bottles not being in the sun, due to my SCUBA training. The folks teaching my firefighting class pointed out that structure fires get hotter than ambient temperatures, or even reflected on asphalt/vehicle roof.

YMMV, depending on the material of which the tank itself is constructed.

 

[leadvagas]

Feel free to mount it on the roof, my gas supplier lists the burst pressure of the aluminum C02 tank at 9500 psi plus. They use the same cylinder for Nitrogen at working pressures of 4000 psi.

 

[tgreening]

It's not the tank that will be the issue, but rather the rupture disk in the tank valve. If I recall the rupture disk will blow at somewhere in the vicinity of 1800 psi, but don't quote me on that. In any case as long as the tank is filled properly it shouldn't be an issue. CO2 tanks are only about 68% full (by liquid volume) as I recall and this is what limits the gas from building enough pressure to blow the disk. Here again I'm going from foggy memory but all the liquid in a properly filled tank will turn to gas at somewhere around 90deg ambient and it's pressure maxes out. If the tank is overfilled and the temp goes up enough all the liquid WILL expand and attempt to turn to gas, building pressure all along the way until it either gets its way or it blows the rupture disk, whichever comes first.

 

[Tools R Us]

Shouldn't be a problem, depending on climate conditions where it's stored. IIRC industrial type cylinders are tested at 4000psi and CO2 burst disks are 3000psi. Most regulator manufactures don't recommend using them with CO2 temps over 120F.

CO2 tank pressure changes with temp, much more so at high temps. IIRC the number is ~150F where the burst disk is likely to go. That is the liquid CO2 temp, so a black cylinder in the sun in desert conditions is easily at risk, have measured 160F in cars setting in the sun here. Know of two that have gone off in cars here.

That said, even if you travel in high temps, your only risking a fill and burst disk. If you have a burst disk failure, get away the gas stream blowing out will freeze burn skin and can crack plastics, etc, so best to mount the cylinder so the disk outlet is pointing towards open area.

This chart is for paint ball cylinders, 2200psi burst disk.

 

[rusty_tlc]

Mine sits in the sun at temps over 100 degrees pretty often, never had a problem in three years.

<insert graph here>

 

[yotawheeler]

i wouldnt worry about it