What would happen if...

[DrMike]

I forgot to drain my tanks and flew in a 747 with them checked in with 100bar in them?

I'm guessing nothing??


I'm not proposing this is done - I'm just wondering if the safety issue is not so much that the tank could explode - but rather the potential of it becoming a projectile if the valve is knocked off or burst disc goes.

 

[Lemonade]

Let’s say you have 100 Bar in them at sea level.
If you take the tanks to outer space where pressure is 0 (1 Bar less than at sea level) tank pressure gauge will read 101 Bar

Burst disks, when they go, it's not violent, just a little noise for a minute or two.

Basically if a tank is in normal shape and is not about to explode on land, it's not going to explode on the plane.

 

[Wendy]

Not to ruin your question, but don't the airlines require that you remove the tank valve when flying, hence this would never be able to happen.

 

[junior diver]

What is the point in airlines not allowing tanks on airlines if it only increases by 1bar if you go into SPACE!

 

[Walter]

The point is, they want to make sure the tank doesn't contain explosives.

 

[Curt Bowen]

Not to ruin your question, but don't the airlines require that you remove the tank valve when flying, hence this would never be able to happen.

I fly all the time with rebreather cylinders. You MUST have the valve removed prior to flying, or you will NOT get on the plane.

They do this because they do not know the contents of a pressurized cylinder, not because the cylinder would not take the pressure change. It could have poisonous gas in it far as they know.

 

[Charlie99]

What is the point in airlines not allowing tanks on airlines if it only increases by 1bar if you go into SPACE!

The risk of a tank blowing up isn't significantly greater, but consequences differ.

Tanks do occasionally fail on land, sometimes injuring or killing someone, most often a dive shop guy. Catastrophic tank failure onboard a 747 might end up killing many more people.

 

[Ontario Diver]

The risk of a tank blowing up isn't significantly greater, but consequences differ.

Tanks do occasionally fail on land, sometimes injuring or killing someone, most often a dive shop guy. Catastrophic tank failure onboard a 747 might end up killing many more people.

First of all, tanks rarely explode. According to my PSI notes, there were 60 recorded SCUBA related incidents (not all causing fatalities or injuries) from 1960 to 2000. Considering the millions of SCUBA tanks that are in existance - they are pretty safe. Almost all tank ruptures tank place upon filling.

If you wish to consider the increase in pressure differential when the aircraft is at its ceiling of 30,000 ft, don't forget that the internal pressure of the tank will actuall drop as it cools . Cooling is usually around 1 degree F for every 1000 feet. So a tank at 70 F on the surface will cool to about 40F at 30,000 ft. Using the Ideal Gas Law, the Volume remains constant for the tank so the pressure will drop... My math says the pressure from the 30 degree drop will go from 3000 PSI to 2830 PSI. If you add on the 15 PSI for elevation the pressure differential that the tank is holding is less than the tank would normally hold at sea level.

The reason tanks are de-valved before flight has nothing to do with explosions.

 

[pasley]

...Burst disks, when they go, it's not violent, just a little noise for a minute or two....

I have no experience with a burst disk letting go. A local diver here in Southern California that I know does. He left the tanks in his car all day at work and as he was driving to the dive site, one burst disk let go. He said it A: Scared the S*&% out of him and B: "made a real mess of his car". Evidently some loose stuff in the back got caught up in the air stream. But I imagine the little noise would be a loud little noise for a while.

Now back on topic. Nothing would happen because A: the airline is not going to let you on with the valves in place and B: even if you got on, I bet the burst disk would blow first.

 

[Lemonade]

I have no experience with a burst disk letting go. A local diver here in Southern California that I know does. He left the tanks in his car all day at work and as he was driving to the dive site, one burst disk let go. He said it A: Scared the S*&% out of him and B: "made a real mess of his car". Evidently some loose stuff in the back got caught up in the air stream. But I imagine the little noise would be a loud little noise for a while.

Now back on topic. Nothing would happen because A: the airline is not going to let you on with the valves in place and B: even if you got on, I bet the burst disk would blow first.

I witnessed one blow on a boat about three weeks ago. Yes, I should have put little in quotes.
It was a loud pop, scared everybody. Then noise same as you just fully open valve on a tank with no reg attached.