Best way to empty an O2 cylinder?

[JasonA]

I have an Al 80 cylinder that has approx 1000 psi of 100% O2. I used it as a dedicated cylinder, but really no longer have a need for it. If I do get back to where I need a dedicated cylinder, it will be a smaller one! I'd like to use it for regular air or nitrox. However, I've been unable to find the best way to empty the O2 from the cylinder and looking for suggestions (outside of diving). Here are my thoughts.

1) Take it to the outside/open space area and empty it slowly through the valve.
2) Take it to a pool and empty it slowly through the valve or regulator.

Does anyone have any guidance, best practices or things I need to watch out for besides fire/combustion hazards? I've looked at several threads and webpages, and found stuff referencing O2, but nothing regarding emptying a cylinder.

 

[rsingler]

How about getting it filled with clean air? That'd give you ~EAN47, for an excellent Nitrox dive above 65ft, or accelerated off gassing for your next deepish air dive.

#1 will work just fine. No nearby ignition source and it's no big deal.

#2 could be a PITA. You have to sit around waiting, so water doesn't accidentally get in the tank when it hits zero.

 

[PfcAJ]

Open the valve and drain it.

 

[tbone1004]

I vote for @rsingler 's idea and just get it topped with air and use it for a shallower dive. No sense in wasting it

If you don't want that, then just breathe it in the pool while practicing skills or on the couch watching a movie or something

 

[billbb]

At a 20ft stop

 

[Tug]

Either do what rsingler recommends or just crack the valve and let it vent in the air. If you don’t want that rich of a blend, bleed it down to about 400psi and top withair for 32%

 

[Johnoly]

On the couch, test your breathe hold improvement.

Take a normal air breath and time how long you can hold it.

Then take several O2 breathes and time how long the improvement is.

You might be able to almost double your time, especially if you make a youtube video about it.

 

[iamrushman]

i vote sit at the bottom of a 8ft pool and have a 1.25ata hyperbaric therapy session...

 

[macado]

Open valve away from any possible ignition sources outside and drain tank (slowly). Over-thinking it, just drain it and refill.

Alternatively, drain to suitable psi (say ~400-550psi of O2) and top off with air to make 32-36% and go dive it.

 

[Landau]

Save it for when you need it. 100% O2 is a great hangover cure.