Potential Safety Improvements in Rebreather Design

[gianaameri]

Just to be clear. You contention is that a rebreather shouldn't physically be able to be assembled wrong, regardless of any administrative or training steps that are standards in the industry that would immediately show that the unit was assembled wrong? So, if, for instance, I were able to install an empty O2 or Dil or fail to pack my scrubber, and choose not to do a checklist (as you yourself claim) that should be the manufacturers fault?

I don't want to dive your perfect rebreather. Sounds like you need a MkVI. Bring extra batteries.

It is not my contention.

It is a requirement that:

“It shall not be possible to assemble or combine the components or parts in such a way that it can affect the safe operation and safe use of the apparatus, e.g. by incorrect connection of the hoses to the breathing circuit.”

I did not write the requirement into law.

The rebreather manufacturers did when they wrote the rebreather standard EN14143:2013 (and before that 2003).

---------- Post added November 29th, 2014 at 04:56 PM ----------

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A ScubaBoard Staff Message...

removed reference to deleted post BoP

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[Wookie]

It is not my contention.

It is a requirement that:

“It shall not be possible to assemble or combine the components or parts in such a way that it can affect the safe operation and safe use of the apparatus, e.g. by incorrect connection of the hoses to the breathing circuit.”

I did not write the requirement into law.

The rebreather manufacturers did when they wrote the rebreather standard EN14143:2013 (and before that 2003).

I understand this. What I am saying is if you mount an empty O2 bottle to the unit that standard is violated. Therefore, no rebreather except the MkVI meets the standard.

 

[gianaameri]

I understand this. What I am saying is if you mount an empty O2 bottle to the unit that standard is violated. Therefore, no rebreather except the MkVI meets the standard.

Well, if you can connect the O2 bottle in place of the diluent bottle... that is reverse components, or connect them such that they look functional, but they are not, and this causes the rebreather to fail dangerously, then the rule is violated.

An otherwise properly assembled rebreather, but with an empty O2 bottle, and warnings going off, then I suspect it would not violate the standard.

 

[gianaameri]

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A ScubaBoard Staff Message...

removed off topic quote BoP

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They made a mistake.

We all make mistakes and when they are inconsequential we don't even notice them and we think we are "cool" and go on with our life.

Do that with a rebreather, and you still think you are cool, but you pass out and drown as exemplified in this case.

That is why we need equipment which is designed to protect (as far as reasonably practical) the ordinary person from his/her ordinary mistakes, and we also need systems, procedures, and controls to further mitigate the risk.

Military rebreathers which cost 10 times more and are used in an environment with strict adherence to system, procedures, and controls result in nil fatality rates.

There is a study from the French which shows this. When I'll find it, I'll post it.

We have too many unnecessary fatalities because equipment is poor and system, procedures, and controls (training and what follows) is poor.

Is not that the case in this fatality?

 

[Wookie]

double post

 

[Wookie]

Agree. And the penalty for our mistakes can seem disproportionate. The world does not care.

One of my brothers best friends is dead because he answered his cell phone and responded while driving on a Texas interstate.

People fall off ladders.

Stuff happens. More often if we are not careful.

These things are understood, and risks accepted in daily life. I understand gianaameri's point. He makes it poorly. If you are going to certify something as intrinsically safe to some standard, and you wrote (or helped to write) the standard, build it to the standard and make it intrinsically safe. Ladders and talking on cellphones at 85 MPH are not intrinsically safe, nor does anyone pretend that they are, nor would anyone certify such a stupid thing. The fact that someone wrote a standard and got it accepted that anything in scuba is intrinsically safe is ludicrous, beyond the realm of thinking of the "common man", and is a lawsuit waiting to happen.

There are 2 points being argued here. gianaameri says that the rebreather was certified as safe and it wasn't. I would argue that there is no such thing as safe scuba diving, and that the standards mean nothing to me anyway. I've seen CE rebreathers, I'm not much impressed by anything with a CE stamp on it. Means China Export to me.

 

[victorzamora]

despite their own manifest contributory negligence (i.e. propensity for actual or potential human error).

This is the crux. My view is that if something kills me DESPITE MY NEGLIGENCE it was my fault, not the fault of the mfg. If something kills me despite my LACK OF NEGLIGENCE then it is the fault of the mfg.

 

[victorzamora]

You forgot the word "contributory."

You forced it in there, and I disagree with it. Negligence is negligence. Properly assembled, the unit works great. Improperly assembled, it works poorly. Improper assembly is the responsibility of the assembler. Neglecting proper procedure is the fault of the assembler.

 

[boulderjohn]

In a recent and still current thread in the Accidents and incidents forum, discussion has centered upon rebreather design. A diver apparently died as a result of assembling the rebreather incorrectly, and the opinion was offered that the rebreather should have been designed so that it could not have been assembled incorrectly. As a moderator, I had to step in a couple of times to remind participants that it was the A & I forum, and discussion had to be centered upon the incident, not on the generic topic of rebreather design. I suggested that those who wanted to talk about this aspect of rebreather design should start a thread in the rebreather forum for that topic. Since that did not happen, I am starting that thread myself.

I am not a rebreather diver, and I am as ignorant about their operation as anyone who got as far in OC diving as I have could be. From that perspective, it seemed to me that the two sides, as polarly opposite and hostile as they appeared to be, were actually very close to saying the same thing. Here is how I would summarize the two opposing viewpoints as I understood them:

Side One: Although it is impossible to make rebreather design 100% foolproof in setup, the design should be as foolproof as possible in order to minimize the possibility of operator error.
Side Two: It is impossible to make rebreather design 100% foolproof in setup, so there is always the possibility of operator error.

Now, no one on side two ever came out and said, "because it is not possible to make the design 100% foolproof, the manufacturers should not make any attempt to include any such safety improvements." On the other hand, it almost seemed to be the implication of some of the arguments. I believe if you asked them that question point blank, they would say, "Of course manufacturers should do what they can to make them as safe as possible, even though it will never be 100%." If so, then the two sides were actually saying the same thing.

Maybe I'm wrong, but that's how I saw it.

So I would like to frame the topic of this thread as follows. I wold like to see a discussion about how rebreathers could be improved to minimize the potential for operator error. Specific references to specific models would be useful. Of course, if you feel it would be wrong for rebreather designers to do this, by all means make that case as well.

 

[boulderjohn]

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A ScubaBoard Staff Message...

OK, since no one could take the hint....

I have created a new thread in the rebreather forum on the topic of the potential for making safety improvements in rebreather design. It can be found here: http://www.scubaboard.com/forums/re...provements-rebreather-design.html#post7282553

I think there is a lot of potential for a very interesting and fruitful discussion. I know I am personally very interested in what could be very useful results. I hope all who want to continue such a discussion will shift to that thread and leave this thread to the topic of the unfortunate death of Jillian Smith.

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