First air fill of the year

[peter_dorset]

I cant find the threads but it was here on the board. There was referance to the o2 being used up in some kind of process inside the steel tank.

Could this be confusion with enriched air? I think that the oxygen when stored can give a different analyzer reading when checked several days later.

But I cannot see how NON enriched air can lose o2 %

Peter

 

[matt_unique]

What should you do on your first fill of the season please?

I emptied my tanks down to 75 bar at the end of the season. Tonight will be the first fill of the new season.

Tanks are in date, 02 clean Nitrox, 15L. So, should I empty them before going to LDS or is it OK just to top up to 240 Bar?

Someone told me if you empty a tank the LDS doesn’t fill them without a visual inspection is that right?

Thanks

Peter

You can demonstrate the tanks had pressure when you came in to prevent contaminents but request the tanks be filled from empty to ensure the quality of the gas. If my tanks sit for a long time I empty them before a fill as well.

--Matt

 

[Warren_L]

I cant find the threads but it was here on the board. There was referance to the o2 being used up in some kind of process inside the steel tank.

Seems to me that oxidation (i.e. rusting) would be probably the only significant process that would use up O2 in the air, at least that I am aware of. So if it occurs to that great of a degree, I wouldn't be using those tanks anymore.

 

[peter_dorset]

Thanks everyone, my LDS emptied the tank via his fill system (a lot less noise) and then refilled them.

I got excellent service from my LDS, Forward Diving.

Cheers
Peter

 

[DA Aquamaster]

I cant find the threads but it was here on the board. There was referance to the o2 being used up in some kind of process inside the steel tank.

Rusting in a steel tank or oxidation in an aluminum tank will both use oxygen and in extreme cases could deplete the O2 in the air. But is would take some serious rust and a period of at least a few years for this to occur. The oxidation process with aluminun is normally self limiting so for it to continue would require water in the tank.

An annual VIP will ensure this does not occur and will ensure the air or nitrox never gets more than 12 months old. If the VIP is current, I would not worry about using the air. If the VIP is no longer current, it needs to be dumped anyway to allow a new inspection.

 

[String]

EU laws are different from US laws regarding visual inspections- they arent 12 monthly here.

 

[DA Aquamaster]

The law does not require them annually here either. Legally under DOT regs, a visual inspection only needs to be done at the time of the hydro test - normally every 5 years. The one exception here is older 6351 alloy Aluminum tanks which now require an eddy current or similar inspection every 18 months.

It is however an industry standard to do a visual inspection every 12 months. And it is a standard that has resulted in a very good safety record at minimal consumer cost.