tanks in hot car

[ScubaDawg007]

Hey guys,

How is the best way to store tanks in the hot car after they have been used, and are empty. Should I let all the air out and leave the valve open? Let most the air out, and leave the valve closed? They may be in the heat for a couple of days or more.

When they are full I plan to keep them up front in the air conditioning with me.

 

[SparticleBrane]

Well first they shouldn't be totally "empty". Do NOT let all the air out and leave the valve open--that's asking for moisture to get inside and start corroding the tank.
Leave whatever air is done after the dive inside the tanks and leave the valve close, is my recommendation.

 

[Sideband]

Hey guys,

How is the best way to store tanks in the hot car after they have been used, and are empty. Should I let all the air out and leave the valve open?.

If you do that you will be paying for a VIP before the next fill.

Let most the air out, and leave the valve closed? They may be in the heat for a couple of days or more.

When they are full I plan to keep them up front in the air conditioning with me.

Just put them in the car. It's that easy.

Joe

Oh. And there really isn't a need to keep them in the air conditioning when full either. If your car is getting hot enough that the burst disks are going to blow then you are probably in danger from heat exhaustion/stroke yourself.

 

[ScubaDawg007]

Thanks Guy`s I thought that was the answer, but I really wasn`t sure.

 

[victor]

Just keep them in the boot (trunk) all the time.
Ensure they cannot roll around and particularly protect the valves.
Don't worry about them getting hot, the will stand the extra preasure.
Never let all the air out, that could allow water in.

 

[Atticus]

Worst case if they overheat is a burst disc will go, which is an easy fix. However you should secure the tanks as was previously mentioned to prevent the valves from being directly damaged and to avoid inadvertant roll ons (valve openings).

 

[Damselfish]

If you want to play with the numbers here's a calculator (scroll down for the temp one) http://www.njscuba.net/gear/trng_12_calculators.html

 

[fishb0y]

If you want to play with the numbers here's a calculator (scroll down for the temp one) http://www.njscuba.net/gear/trng_12_calculators.html

You gotta love that site...

 

[mike_s]

I agree with the others. Don't empty them and just put them ni the car.

However, I've noticed that my trunk is much cooler than the passenger section after sitting in the sun. I guess it's because of the 'greenhouse effect' of the windows. So I'd suggest keeping them in the trunk.

BTW.. I've never had a problem leaving full tanks in the trunk during a hot (90f + ) day. I just try not to do it except when no other easy way is available.

 

[ScubaJorgen]

Full tank in the car
Say, you put away a cylinder filled with 200 bar (2900 PSI) in your car. The cylinder was filled at 20 °C (68 F), your car heats up to 80 °C (176 F).

Some guy in the past has made up that pressure times volume divided by temperature is constant:

pV/T = constant

The fun part is that T is absolute temperature, in Kelvin (K), not in Celcius, Fahrenheit, Hotdogs, or whatsoever.

Volume is constant, so we can say

P/T = constant

200/(273+20) = pressure_in_the_cylinder_after_placing_in_car/(273+80)

The pressure_in_the_cylinder_after_placing_in_car will be 241 bar (3500 PSI).

Regular tanks should be able to handle that.

The real risk?
What if your car catches fire. You've got a couple of filled tanks in your boot :54:. Firemen arrive and start putting out your car. Than your alu tank decides to melt.

I think I've heard that your o-rings should give way before the aluminium melts. Can somebody confirm? Or does this apply to steel tanks and are aluminium tanks equiped with break plates. At what pressure do these plates break? We should call in MythBusters again...