Would you dive with 3 year old nitrox?

[tmassey]

there's a vast difference between a steel cylinder with a 46 year old fill, and an aluminum cylinder with a 3 year old fill.

From @tursiops perspective, there is absolutely *no* difference. And the misunderstanding between the two of you highlights a very big hole in many divers’ training and perspective, often through no fault of their own.

For open water divers, no real mention of the contents of their tanks is ever really made. It’s air. It’s always assumed to be air. In fact, they are given no instructions or procedure for verifying that. Again, it’s always assumed to be air.

Unfortunately, scuba tanks can be filled with all kinds of things. No doubt air is the most common, but far from the only thing. And some of those things that tanks can be filled with are deadly. Advanced and especially technical divers tend to use those gases. And so such divers are given simple, specific instruction: always personally check every tank you are going to breathe, and do so shortly before you use it. In fact, failing to check the contents of a tank is the leading cause of death for technical divers!

So, @tursiops’ terse (see what I did there?) point, stated in his typically crusty manner, is that it should be standard procedure for every diver to check every tank before they dive it, especially a tank that has been sitting there for any length of time, whether three years or 43 years. As a technical diver, I completely agree. However, I also realize that not all divers have been trained to follow that procedure, as risky as that might be for any diver of any skill level.

Which is why I’m taking the time to write this little missive. Hopefully it might bridge the gap. For a diver who has not been instructed on the importance of checking tanks, diving with a three-year-old tank without checking might be standard procedure. For a diver who has been instructed to check, three *days* could be too long. Even if they filled it themselves. Even if it hasn’t moved an inch from where they left it when they filled it. It’s procedure. And it’s designed to save lives.


Now, why it’s not standard procedure for open water divers is a little bit beyond me. I fill tanks for friends of mine. Most use nitrox, but some still use only air. And yet I make even them analyze every tank — for oxygen *and* carbon monoxide. Why? Because *I* might have made a mistake. Just because *they* wanted air doesn’t prevent me from putting something unknown in it. So, we check. Every time.

Not telling anyone else what they need to do for their own diving. As @The Chairman says, dive and let dive. But I wanted to possibly give a different perspective for others to consider.

 

[davecampbell]

my statement was that the age of the gas wasn't an issue, not that it shouldnt be analyzed. Im going to extrapolate that since the OP gave a nitrox reading in %O2 that they were analyzed and labelled at some point by them. I at no point said it was a good idea to dive a "mystery" tank.

All my cylinders are checked by me, but not always the day they'll be used. They're labeled (by me) with the contents, date tested, and pressure when tested... then sometimes they sit for a while between dives. No one else fiddles with my gear, and as long as the label is intact, there is no mystery as to what the contents are. If the label was missing or unreadable, no assumptions would be made, and they would be re-analyzed.

Further, the difference between steels and aluminum was brought up, because there is a chance a wet fill in a steel might corrode and decrease the O2 content, especially over 46 years. Filter quality and air standards were lower way back then. In an aluminum cylinder, filled relatively recently, the risk is minute.

Basically what I'm getting at is that if the cylinder had a clean, dry fill with good gas, and was analyzed 3 years ago as such, it will have contain the same gas today.

 

[grf88]

If air goes off we are all in for a lot of trouble.

 

[industrious95]

Thanks for all the responses. Of course I check them personally when I pick them up at my LDS, and I mark them.

I normally would not think to re-analyze them before use. But I normally dive twice a month. It's certainly not a big deal to check this one out before I use it. Being extra careful has kept me happily diving for 40 years...