How Hot

[littlejohn]

With summer coming soon I was wondering how hot a tank would get i n the trunk of a car?
I dive HP tanks so starting at 3400 psi at room temp, how high will the psi go in the heat of summer.

 

[Scared Silly]

Boyle's law

Pressure / Temperature = Constant

 

[DA Aquamaster]

140 degrees is a reasonable estimate for the temperature inside a car trunk.

The math for boyle's law is a simple ratio, but you have to use an absolute temperature scale.

70 degrees F is 539 degrees on the Rankin scale. So 140 degrees F = 609 degrees R.

If you divide 3400 psi by 539 and then multiply that number by 609 you should get the pressure at 140 degrees F (609 R) of 3841 psi. That is a 441 psi increase but it is still well within the limits of the tank and burst disc as the test pressure for a 3400 psi e series tank is (I am pretty sure) 3/2 or 1.5 times the service pressure - which would be 5100 psi. The burst disc pressure is required to be in a range of 90-100% of that pressure (4590 to 5100 psi).