Testing your breathing Gases Prior to Diving

[MXGratefulDiver]

Please remember that I am talking about air fills in non-O2 clean tanks.

I equate "reputable" with "responsible". Yes, is there a possibility of an error, but it is a miniscule risk.

I really like these discussions because it shows how people will go to the extreme for scuba diving, but I bet they do not take the same level of safety in their daily lives. I equate analyzing my air fills with wearing a helmet, fire retardant suit, and five-point harness while I drive. Is it safer? Yes. Is it overkill? Yes.

I think it depends on what resources you have available. If you're using a dive shop that only pumps air, then the risks of getting something besides air are essentially nil. If you're using a shop that also pumps nitrox, uses banks, offers trimix, and fills argon bottles, then the risks of getting something besides what you ask for are significantly greater.

The "reputable shop" argument doesn't cut it with me ... a reputable shop would be one that insists that every nitrox diver analyze their tanks when they come in to pick them up. I frequent a reputable shop multiple times a week, and they won't let me out the door with my cylinders until I analyze them ... even the ones I occasionally ask for that only contain air.

Why? ... well ... because the reputable people who fill them are human, and humans sometimes make mistakes. "Trust, but verify" isn't just a political slogan ... for those of us who do a bit more than just occasionally dive a reef or quarry, it's words to live by.

And let's not forget the context of the incident that started this conversation ... that guy was diving inside a cave, carrying multiple breathing gasses. Not analyzing your tanks in that case is blatant complacency ... and at that level of diving, complacency kills.

Only YOU are responsible for your safety ... that extends to verifying that you're breathing what you think you're breathing. In an activity where your ascent profile depends on the gas you use, this seems to me like a no-brainer.

... Bob (Grateful Diver)

 

[Suzuki416]

back to this
If you don't wear a seatbelt, you 'will not' die - unless you have a major accident
If you take a O2 cylinder to 100ft & start breathing off it then if you make it out I'd suggest getting a lottery ticket.

 

[guruboy]

If anything, I would say it's closer to putting on your seatbelt, speeding up to 60mph, and then slamming on the brakes to check that the belt locking mechanism works. But I think seatbelts are a bad analogy.

I would compare it to checking the octane of the gas coming from the pump, but getting the wrong gas won't actually kill you, so... meh

 

[Dr. Lecter]

Yes, is there a possibility of an error, but it is a miniscule risk.

There're two things you need to consider when talking about risk: probability of occurrence and magnitude of harm. You seem to be inordinately focused on the former; as to the latter, I don't like Russian roulette whether the odds are 1:6 or 1:somemuchlargernumber. When the magnitude of the harm is a flat 'you're going to seize without warning and drown before you can take any action', I'd say even a low probability of occurrence justifies the overkill of analyzing the tank.

 

[Jim Lapenta]

And again it is not just you that is being put at risk. It is your team and the people who may have to put themselves at risk to save you. Personally if someone were that selfish I'd prefer to leave em rot rather than risk another person's lfe. Be a good reminder of why you don't do that to see someone's corpse just off to the side of a tunnel, swim thru, or passage with a sign saying "Analyzing my gas was too much bother and not that big of a deal. Have a nice day!"

 

[nimoh]

I'm most concerned about the CO poisoning as I'm never deep enough to worry about an MOD on Nitrox and don't any other mixes.

you don't dive below 20 feet?

 

[DBailey]

There're two things you need to consider when talking about risk: probability of occurrence and magnitude of harm. You seem to be inordinately focused on the former; as to the latter, I don't like Russian roulette whether the odds are 1:6 or 1:somemuchlargernumber. When the magnitude of the harm is a flat 'you're going to seize without warning and drown before you can take any action', I'd say even a low probability of occurrence justifies the overkill of analyzing the tank.

Trust me, I understand where you are coming from.

I dive air. I only dive air. My tanks only get air in them. The two shops that provide my air do "air only" fills 99% of the time. To accidently fill a tank with anything other than air is a special procedure for them. For someone to be brain dead and accidently put > 20% air in my tank would mean that they took a lot of extra steps which would go against the whole brain dead theory.

Based on the billions of tanks filled over the years, the probabilty of getting a bad fill is remote. Ok, now let's say that particular fill hits my diving lottery, the odds that it is a "bad enough" fill to kill me are again remote (for this discussion, 22% O2 could be a "bad fill").

I am not being reckless or cavalier, but practical. For my diving, I do not see the benefit of using another piece of equipment (that can fail as well) to guard against some miniscule risk.

Do you only analyze it once with one analyzer? Or do you have redundant analyzers by different manufacturers to insure your gas safety? Where do you stop? For you, where does it become overkill? I understand people diving different mixes and multiple tanks need to analyze and mark their tanks. I wouldn't want to trust my memory as to what gas is in which tank either. There were those in this thread that implied or out right stated that every air diver should analyze their tank OR DIE!! For that part of the discussion, I respectfully disagree.

 

[MXGratefulDiver]

There were those in this thread that implied or out right stated that every air diver should analyze their tank OR DIE!! For that part of the discussion, I respectfully disagree.

... again ... it boils down to resources. You are getting fills at a shop that only does air ... or in the rare circumstances when someone wants nitrox, they PP blend. So in your case, the risk is extremely low.

In my area, there are several shops that fill using a blending system ... or from banks ... that routinely do both air fills and nitrox fills ... many that also fill trimix or argon using the same whips and a sequence of valves. For people getting their fills at those shops, the potential for a dangerous fill is much higher ... even though those are all reputable shops. The final check of throwing an analyzer on the tank when you pick it up is pretty negligable, considering the potential consequences. It takes about 30 seconds. It costs you nothing (the shops supply the analyzer) ... and it's a routine that all the better shops in town will insist on.

Overkill? I don't think so. It's a simple safety check that the person who filled your tank turned the correct valves in the correct sequence to give you the mix you asked for. For those who use shops that offer multiple breathing gas choices, it's a pretty sensible precaution.

... Bob (Grateful Diver)

 

[elan]

I dive air. I only dive air. My tanks only get air in them.

How do you know? You do not analyze your gas.

---------- Post added August 14th, 2013 at 05:55 PM ----------

Do you only analyze it once with one analyzer? Or do you have redundant analyzers by different manufacturers to insure your gas safety? Where do you stop? .

2 different analyzers - 1 at the shop when I pick up the tanks, 2 with my own analyzer before the dive

 

[PfcAJ]

I get it if your shop literally only fills air. I worked at a place like that in the Keys. Unless the atmosphere changes dramatically somehow, its air. Pretty reasonable to not analyze in those situations. Every other situation though...