scuba tanks in my car trunk.

[Johan Broere]

Summer is here and it is heating up. I drive around with my tanks in my car. I treat them like leaving animals in the car and I leave the windows open. If it gets to hot I take them out so the disk won't go. The only story I know is of the whole neck that came off from roling and banging around. Oh and another one flew through the truck box and garage wall. Who has a story regarding tanks and what you will never do again. How hot is too hot ?
Tanks for the warnings and information, Johan.

 

[seaducer]

No stories but...tanks filled to 3000PSI can easily reach 3500 PSI just sitting in the sun on a summer day, so inside the car where it gets really hot is not the best place for them. I think you have the right idea and I treat mine the same.

Having seen the tank experiments on Mythbusters, the idea of a tank losing integrity is a very scary one indeed.

 

[bamamedic]

I once wrecked a car and knocked the valve loose...thankfully, the air just leaked out slowly.

Nowadays, I'm very careful as to how I place my cylinders in my car.

 

[iztok]

In order for a tank filled at 3000 PSI (at 70F) to reach 3500 PSI the temperature would have to reach 154F.

 

[Lee Taylor]

Here is a story for you. Sorry it does not have anything to do with heat.

I had finished a day of black water diving and fossil hunting. I was tired, dirty, hungry, and driving home alone. I had two 80 cube aluminum tanks rolling around in the car trunk. I was breaking for a traffic light when I heard this LOUD hissing sound. By now my mind was not on the scuba tanks in the trunk. I looked around (with a what the hell is that look on my face) wondering where the loud hissing was coming from.

After a few long moments, it began to sound like it was coming from my trunk compartment. Then it dawned on me that somehow a scuba tank valve must have opened. I parked, scampered to the trunk, opened it, and sure enough, there was a tank hissing away. It was rather comical when I look back on it.

 

[seaducer]

In order for a tank filled at 3000 PSI (at 70F) to reach 3500 PSI the temperature would have to reach 154F.

Which is not hard for metal to do when sitting in the summer sun.

 

[eponym]

Summer is here and it is heating up. I drive around with my tanks in my car. I treat them like leaving animals in the car and I leave the windows open. If it gets to hot I take them out so the disk won't go. The only story I know is of the whole neck that came off from roling and banging around. Oh and another one flew through the truck box and garage wall. Who has a story regarding tanks and what you will never do again.

I will never again carry a tank on my shoulder. If it falls (for whatever reason, don't ask) and lands on the valve, the least harm is to deform the nice round o-ring seat.

How hot is too hot ? Tanks for the warnings and information, Johan.

Good question! If your burst disks are designed to fail at 40% over rated fill pressure (that's an industry norm, I believe), that works out to 4200 psi for a 3000 psi AL80. Disks, being physical things. will fail individually at different pressures, of course: perhaps 25% over to 66% over rated pressure.

Pressure increases with temperature, but we have to work with absolute temperatures (F + 460). A little calculator work will tell you that a tank filled to 3000psi at 70F, when warmed all the way through to double that (140F), will register a tad under 3400psi. Plenty safe. For 3500psi I get 158F, close enough to what Iztok said. To get to 4000psi (still well under the theoretical burst disk failure pressure, but not if the disk fails at rated+33%)) requires the air in the tank to be at 246F! (1.33 times the initial temp in absolute measure).

-Bryan

 

[iztok]

Which is not hard for metal to do when sitting in the summer sun.

Actually this is rather on the top range of what you can expect. AL80 is hydro tested to 5000 PSI (I think). If I remember burst disk is at 4000 PSI so the temperature in car would need to reach 244F.

 

[obsession600]

In order for a tank filled at 3000 PSI (at 70F) to reach 3500 PSI the temperature would have to reach 154F.

Here are some examples of car temperatures exceeding 130 degrees.
from The Weather Channel

pet people

Looks like some posts happened between me reading and replying to this thread. It looks like we have reached the conclusion that 245 degrees is our target and that is not happening.

 

[scubaflier]

sounds good for solar power companies but its really not so
pressure only incresses 5 psi per deg. above ambient. 70f
do the math and just a little thinking
@244f if you left a bollle of water in your car it would explode does that happen? no
Its not good to let a tank get to hot but the temp to cause catsotropic failure in a car means the thing is on fire and you got bigger problems anyway.