Question NITROX (in less than 40 foot of water)

[PR_SMITH]

Strictly for the sake of arguing, what could be in them that would be actually dangerous at those depths? 100% oxygen? Some sort of hypoxic mix?

Entirely possible for them to be filled with 100%. Every tank must be analyzed before diving. I had a friend die from not doing that. He was doing a cave dive, got to 90ft, switched a tank that had not been analyzed, tank was 100%, he died.

 

[myrddin]

All good folks... I am planning on driving out to my LDS today (tomorrow at the latest) to have them analyze the tanks. To be extra clear... No they did not come from a dive shop, however they did come from an instructor. He had them, I made an offer, and they just happened to be full. anyway... ill share what they turn up being... if it's not exactly what it shows on the tank, I would be really surprised. But rest assured, while I am at the dive shop, I am also signing up for the next course...

again, I appreciate everyone's response... I knew what to expect. and agree the right answer is to be certified for the things we do. I was just looking for conversation and input. If the tank is not right, I will have it filled while there. If it is right... they will not go to waste.

thanks!

 

[jadairiii]

If you can watch while they are analyzed, then I'd dive it as air.

There's no magic to diving nitrox and no new technique requirements other than knowing your maximum operating depth. This is why the operating a motorcycle on a car license analogy is inapplicable here. A conservative maximum operating depth for 32% is 110ft. Stay away from that and you'll be fine.

Based on what Lowwall just wrote, you are 3/4's of the way to your Nitrox card!

 

[Twoblues]

Entirely possible for them to be filled with 100%. Every tank must be analyzed before diving. I had a friend die from not doing that. He was doing a cave dive, got to 90ft, switched a tank that had not been analyzed, tank was 100%, he died.

I'll bite. Who would put pure o2 in a scuba tank? I assume he's writing of a full sized 80.

 

[boulderjohn]

I'll bite. Who would put pure o2 in a scuba tank? I assume he's writing of a full sized 80.

Me.

I have one in my garage right now.

It's related to decompression diving.

 

[Eric802]

Get whatever's in there analyzed, for sure. It'd be foolish to use them otherwise. And taking a Nitrox course is never a bad idea.

Once you take the course, you'll realize that (once you know for sure that the tank is 32%) you totally could have just dived the tanks without the course.

 

[rick00001967]

All good folks... I am planning on driving out to my LDS today (tomorrow at the latest) to have them analyze the tanks. To be extra clear... No they did not come from a dive shop, however they did come from an instructor. He had them, I made an offer, and they just happened to be full. anyway... ill share what they turn up being... if it's not exactly what it shows on the tank, I would be really surprised. But rest assured, while I am at the dive shop, I am also signing up for the next course...

again, I appreciate everyone's response... I knew what to expect. and agree the right answer is to be certified for the things we do. I was just looking for conversation and input. If the tank is not right, I will have it filled while there. If it is right... they will not go to waste.

thanks!

good on you for asking first and for making the right call

 

[Sevenrider860]

Unless the shop is partial pressure blending, there wouldn't be anything higher than 36% in the tanks. They are aluminum 80s, so if they were to be filled with deco gas the tanks would have to be labeled as such. I would dive them in less than 40 feet.

My local shop does not partial pressure blend and we can easily get higher than 40% with continuous blend (aka Nitrox Stick). I know another dive shop that uses a Membrane system and can easily fill to 38 to 40%.

 

[boulderjohn]

I'll bite. Who would put pure o2 in a scuba tank? I assume he's writing of a full sized 80.

Here is a more extreme example.

Not long ago, a man visited a friend's house, and his children used some of the friend's equipment to dive in his pool. The cylinder was pure helium. Yes, the children died.

If you have to rent big oxygen and helium supply bottles, when you are done with your current dives, you don't want to return them to the gas supplier half full, and you don't want to pay for weeks of cylinder rent until your next trip, so you fill some of your own tanks with oxygen or helium and return the supply bottles. Of course, you had better damn well have them properly labeled as such.

Here is another story. A diver in South Florida was about to do a dive with his double tanks when he broke his foot and had to wait several months. When he was healed, he remembered that his tanks had air in them, and he took them to dive the Hydro Atlantic, a wreck with a top deck 150 feet deep. He must have had a last second memory that the tanks actually had 36% in them, which is likely why he tried to sprint to the surface before drowning.

 

[Sevenrider860]

Strictly for the sake of arguing, what could be in them that would be actually dangerous at those depths? 100% oxygen? Some sort of hypoxic mix?

Yes and Yes.

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