HP tanks and temperature change?
Do I need to be worried that my 4500psi tanks are in a unheated garage right now? Also will soon have a furnace in garage, will the temperature change affect the bottles? I know with propane we keep the bottles outside of the work shelter so they don’t heat up and explode and was wondering if same could be true for HP air tanks? I Know the propane is mostly liquid in the tank, but just want to play it safe.
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That made my head hurt! 😳 but thanks! 😉
Knife
My best guess is that you’ll be fine. However, it only take a bit of math to actually find out. The pressure relation can be approximated using the ideal gas law, PV=nRT.
P: Pressure (atm)
V: Volume (L)
n: moles of gas
R: gas constant (0.082057 L atm K−1 mol−1)
T: Temperature (K)
Assuming we have a standard 88CF fill of an ideal gas, that represents a total of 105.4 moles. Using 4500psi (306.2 atm) as the fill pressure at room temp (288K is the associated room temp for cubic feet), we have a tank volume of 8.14L. Now if we heat that tank up to 100F (311K), the pressure increases to 4857psi (330atm). A little high, but not likely to destroy itself. At 130F (hot car scenario), the pressure is all the way up to 5114psi. While I don’t know the failure rating for these tanks, 5000psi looks concerning. I put together a quick excel calculator if anyone would like to check the numbers, but I can’t upload the document (I get an “xlsx is not allowed” error)
He said that the only danger is leaving a fully charged tank in a hot car in the summer.
😆 Well, not the only problem. Ihear that if you stick your toung to a really cold bottle, it can be a real Hoot! 😈 😆
Propane is kept outside because of potential leakage and ignition in a confined space.
I’d just check that the air tanks don’t warm to a pressure that would cause the burst disk to develope a leak. I heard mine hissing from another room when it so to speak blew. Actually just a rapid release that took a couple minutes to drain the tank. Joe Brancato of airtanksforsale.com sent me a new burst disk and saved the day.
I think there is an equation somewhere that can tell you how much pressure will in/de-crease with temperature changes.
good to know, thanks for the infrmation
I called a buddy of mine who owns the dive shop that fills my tank. He said that the only thing that would be affected is the amount of pressure avaialble in the tank. As the air becomes colder it becomes more dense thus lowering the pressure.
He said that the only danger is leaving a fully charged tank in a hot car in the summer. 😯 😯
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Very true, not recommended. Anyway, every cylinder comes with a burst disk (in the worst case you will have only to replace).