Nitrox

[JagDiver]

Hey everybody.

I have a question. I need to replace the main drain in my pool. I borrowed a tank from a freind and it is nitrox. The pool is only 9ft deep. He said i should be fine, just dont come up to fast. I was wondering you guys think. Any sauggestions, i have never used nitrox. Also looking to go to either bon aire or little cayman next year. Anybody been?

Thanks, Jagdiver

 

[TSandM]

Welcome to ScubaBoard, Jagdiver!

One of the most important things about diving Nitrox is that you analyze the tank to know exactly what is in it. Admittedly, you could breathe 100% oxygen safely at the depth you're talking about, but it's still important to know what is in the tank. Oxygen becomes toxic beyond certain partial pressures, which is why you need to take a Nitrox class to understand diving Nitrox in open water. But the likelihood of a problem, assuming the tank contains what your friend says it does, is very low. (I'm assuming you're a certified diver to begin with, of course!)

Your question about Bonaire and Cayman would be best asked in the regional subforum for those areas. I think you'll find a TON of people here who regularly dive Bonaire, and lots of information about the Caymans, too.

 

[JagDiver]

Yes i am certified. The tank has a piece of tape on it that says 32.4. i am guessing that is the nitro.

 

[tursiops]

You are guessing wrong....that is the oxygen percentage.
There will be no problem at 9ft.....but without certification for nitrox and without analyzing the tank, you are violating standards and best-practices.

 

[Stoo]

You are guessing wrong....that is the oxygen percentage.
There will be no problem at 9ft.....but without certification for nitrox and without analyzing the tank, you are violating standards and best-practices.

Mercifully, as long as you don't happen to have the SCUBA Police over for a BBQ, you'll be fine.

You're question about coming up "too fast" is a little concerning. The SPEED of ascent from 9' is of little consequence AS LONG AS YOU ARE BREATHING AND HAVE A CONSTANT AIR/NITROX/WHATEVER exchange going on.

And I'll go out on a limb and pretty much guarantee that you will not get bent, diving to 9', on 32.4% nitrox. But don't get your finger stuck in the drain on the bottom. You should probably carry a knife, just in case...

 

[redacted]

If a friend loaned me a tank for a 9 ft dive and said it was nitrox, I would thank him and do that dive with no concerns about the gas.

 

[Hickdive]

The big danger of this dive is not the Nitrox (even if it was pure oxygen that isn't going to be a problem at the depth of 9 feet) but the differential pressure i.e. getting part of yourself or your equipment sucked into the drain and trapped whilst you're working on it.

It is very easy to underestimate what differential pressure can do. For example a 9 square inch drain is roughly 64 square centimetres and at a depth of only 9 feet (2.74 metres) a cover plate placed on the drain and the drain pipe emptied would have a force of around 76kg acting on it.

Isolate the drain if you can so it cannot empty whilst you're working on it, tie a lifeline to yourself and have someone strong topside ready to pull hard on the line if you signal you're in trouble.