Potential Safety Improvements in Rebreather Design

[Garth]

The prism 2 is a great rebreather. This incident doesn't effect that at all. Removing all possible error is the most idiotic idea I've ever heard. If we were to achieve that I suppose we wouldn't actually need any training then right? If there was no way to screw it up why would you need to take a course to effectively assemble and dive the rebreather?

Look, a rebreather takes more time to prepare and each step during the assembly process is mandatory. Mandatory to complete and mandatory to perform properly.




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[PfcAJ]

Removing all potential for error isn't reasonable.

Removing as much potential for error as possible certainly is reasonable.

 

[tstormdiver]

Removing all potential for error isn't reasonable.

Removing as much potential for error as possible certainly is reasonable.

Boils down to quality instruction & the individual's discipline to follow the accepted procedures for assembly & pre-dive tests.

 

[Garth]

Removing all potential for error isn't reasonable.

Removing as much potential for error as possible certainly is reasonable.

I agree. I find my rebreather to be very simple and designed well. I wouldn't see a need to add anything additional to what I have. I work on my own abilities however every dive. Staying vigilant is important.


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[dreamdive]

I'm sorry, but this cannot go unchallenged. The Prism (and Prism 2) use a radial scrubber. You cannot pack it half full and have a usable rebreather. The gas path would effectively bypass any scrubber material completely. What you have is a CO2 recirculating machine.

I doubt anyone could breath from such a rebreather for even a few minutes without getting massive CO2 problems.

EXACTLY! But it did happen and that person was lucky to be pulled out by another diver after complaining of not feeling too well. Turns out that he was trained properly on how to pack his scrubber. Somehow and somewhere/time he decided that he will only pack what he needed for a dive and almost died. He also failed to go over a checklist and pre-breathe on the boat. THAT IS WHY WE HAVE CHECK LISTS AND PROCEDURES IN PLACE.

The notion of having a fool-proof rebreather is unrealistic.

---------- Post added November 29th, 2014 at 09:15 AM ----------

Gian,

Do you actually dive a rebreather? If so, what unit and how much time do you have CCR?

I am asking since you have very strong opinions regarding CCR.

Claudia

 

[tstormdiver]

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A ScubaBoard Staff Message...

removed quote of deleted post.. bowlofpetunias

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Simple, yet complex, at the same time.

Before I got my rebreather, My instructor constantly drilled me on Nitrox formulas. Being that I am also one of his OW instructors & his repair technician, he would point out my mistakes, even the small ones, & say, "if that was your rebreather,... you would be dead". It changed my way of thinking & analyzing things. Once the unit arrived, I completely built & broke down the unit, by the check lists & ran the pre-dive tests more than a dozen times, before I even took the unit to the pool. Now,... being that I am staff & work for my instructor, I was in no hurry to get the course done & we took a much more thorough & complete route. From the time I got my unit until I completed the course (MOD 1) was about 10 months (Dec.- Oct.). I spent the winter in the pool getting used to the buoyancy characteristics & the little nuances of the unit. By the time I took it to Open water in June, I had over 40 hrs in the pool alone. My instructor & I made 10 or more trips to the local quarry for my course. I was able to get in a couple post training dives before the weather started turning cold & went back to the pool to further refine my techniques. It took me most of this past summer to gather the necessary hours & experience to begin my CCR Cave training. I got a little taste of that about a month ago. Hopefully, in the spring, I'll be going back & gaining much more. Learning to dive a rebreather has taught me to be much more critical of my attention to detail,... a valuable asset. I fully realize,... I'm human, I make mistakes (comes with being human,... unfortunately), Yes, my rebreather can kill me,... But I am thankful that my instructor cared enough to slow me down & to be as thorough as anyone can be.

 

[tstormdiver]

No, just build the equipment to reduce risk to as low as reasonably practicable (lesson number 1 learned from this fatality).

And what is that? It can be pretty broad when you come down to it. Equipment That is built to reduce the risk as low as reasonably practical, may be overkill for 1 person, & not nearly enough for another.

 

[gianaameri]

And what is that? It can be pretty broad when you come down to it. Equipment That is built to reduce the risk as low as reasonably practical, may be overkill for 1 person, & not nearly enough for another.

Not really.

Every diver makes mistakes.

We have had divers like in this case who have little experience, made mistakes, and died, and divers in other cases with a lot of experience who have made mistakes and also died.

Some fatalities are unavoidable, but equipment which is built to good standards and to reduce risk to as low as reasonably practicable is what in this day and age is expected in all realms of life and human activity.

I think this is what the Coroner feels strongly about, and me too.

 

[tstormdiver]

Not really.

Every diver makes mistakes.

We have had divers like in this case who have little experience, made mistakes, and died, and divers in other cases with a lot of experience who have made mistakes and also died.

Some fatalities are unavoidable, but equipment which is built to good standards and to reduce risk to as low as reasonably practicable is what in this day and age is expected in all realms of life and human activity.

I think this is what the Coroner feels strongly about, and me too.

Odd,... Since it has been shown that nearly all rebreather fatalities have been shown to be the result of operator error, not machine design, whether, because of being a inexperienced or careless or such. Good training & having the discipline to follow accepted checklists would go a massive way in minimizing risks. For that rebreather to have been in the shape it was in for the accident to occur, there just about had to be red flags that were not noticed or ignored when/ if the pre- dive checks were done.

 

[gianaameri]

Odd,... Since it has been shown that nearly all rebreather fatalities have been shown to be the result of operator error, not machine design, whether, because of being a inexperienced or careless or such. Good training & having the discipline to follow accepted checklists would go a massive way in minimizing risks. For that rebreather to have been in the shape it was in for the accident to occur, there just about had to be red flags that were not noticed or ignored when/ if the pre- dive checks were done.

You are applying reverse logic.

It is the equipment who is supposed to protect the operator and not the operator to protect himself/herself from the equipment.

You have a metalworker that cuts or welds metal and he makes a mistake and cuts off his arm and burns off his leg.

If the equipment was not designed to protect the metalworker from what is unavoidable - that is human error - then the equipment is at fault.

Rebreathers are classed as "Personal Protective Equipment."

To the extent that it is practicable, the equipment is to be designed to protect the user from all hazards, including human error.

This does not mean making the equipment 100% idiot proof and/or 100% dependable (it would be too costly and impractical), but it should incorporate all those little engineering features and designs which reduce risk - including that of human error.

In this instance, according to the Coroner report and HSL the equipment did not meet one of those same safety features which collectively the rebreather industry had unilaterally decided it should instead meet to protect the user from death due to user assembly error.

She did her 5 minute pre-preathe as prescribed by the manufacturer and training agency and two buddy rebreather divers spotted nothing wrong (and could not save her).

Food for thought!