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Thread: 8000 Feet, One Spool and One Total Loop Failure

  1. #41
    RBW Member mempilot has a reputation beyond repute mempilot has a reputation beyond repute mempilot has a reputation beyond repute mempilot has a reputation beyond repute mempilot has a reputation beyond repute mempilot has a reputation beyond repute mempilot has a reputation beyond repute mempilot has a reputation beyond repute mempilot has a reputation beyond repute mempilot has a reputation beyond repute mempilot has a reputation beyond repute mempilot's Avatar
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    Re: 8000 Feet, One Spool and One Total Loop Failure

    Quote Originally Posted by AM  View Original Post
    What does that prove exactly? That water doesn't ingress when you breathe the BOV?

    That testing is not a substitute for proper WOB testing which verifies that in a hypercapnic event....
    Why must you turn every conversation into your crusade for testing?

    Operational checks ensure the unit works before you need it. Your argument would mean that doing any kind of diver related check is invalid since certification testing is the way to go.

    AM, certification is the first step. The light bulb is only guarrenteed to work the last time it lit the room. The next time you flip the switch, it may not.

    Maybe we should all start sending our units in for bench diagnostics before every dive to satisfy your crusade.

  2. #42
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    Re: 8000 Feet, One Spool and One Total Loop Failure

    Quote Originally Posted by mempilot  View Original Post
    Why must you turn every conversation into your crusade for testing?

    Operational checks ensure the unit works before you need it. Your argument would mean that doing any kind of diver related check is invalid since certification testing is the way to go.

    AM, certification is the first step. The light bulb is only guarrenteed to work the last time it lit the room. The next time you flip the switch, it may not.

    Maybe we should all start sending our units in for bench diagnostics before every dive to satisfy your crusade.
    You are missing the point completely. Operational checks verify that equipment is working *in the capacity it has been designed, tested and verified to do*. Operational checks are not a substitute for the initial design and test phase, they are a secondary check which as a matter of course would be expected to be conducted.

    If I test a regulator underwater, what am I testing? Am I testing that it works, i.e. it does not leak water? I am certainly not testing that it performs adequately in accordance with, for example, the Navy Diving Experimental Unit WOB guidelines of 1994. If equipment is never tested against any "performance" criteria, then what are the success criteria to deem that equipment as being acceptable for safety-critical applications?

    "It doesn't suck in water when you breathe at 40m, great, it works!" is a bit different to...let's add this to a 100m rated piece of equipment and hope it performs adequately during a hypercapnia event at that depth.

    The light bulb analogy is ludicrous. It may or may not work when you flick the switch next time? Life support, safety critical equipment in the form of a breathing regulator, relied upon as a substitute for an EN250 high performance regulator, must work EVERY time. A light bulb failing won't kill you, a BOV failing (because it was not tested and verified against appropriate parameters) WILL!

    If there are no prior metrics used to determine equipment's fitness for purpose, against potential physiological events AT DEPTH, other than, does it breathe and not leak water, during an operational test, then no amount of operational tests will ever define that the equipment is able to perform *adequately* under demanding conditions.

    All the operational tests in the world do not mean a piece of equipment will function in the way you expect and NEED it to, when your life depends upon it - that is a function of appropriate extensive testing and determination of failure modes and effects criticality analysis by *objective* means which determine performance at a much higher rate than that needed for an "average" human i.e. a breathing machine, not *subjective* means, i.e. a human.

    Certification is a different matter entirely.

    Regards

    AnneMarie

  3. #43
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    Re: 8000 Feet, One Spool and One Total Loop Failure

    Quote Originally Posted by AM  View Original Post
    Operational checks verify that equipment is working *in the capacity it has been designed, tested and verified to do*
    Which was Andrews point of his check. Good, so you agree.

    You are the one missing the point completely, and are going off on a tangent.

  4. #44
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    Re: 8000 Feet, One Spool and One Total Loop Failure

    Quote Originally Posted by AM  View Original Post
    What does that prove exactly? That water doesn't ingress when you breathe the BOV?

    That testing is not a substitute for proper WOB testing which verifies that in a hypercapnic event, said BOV will perform adequately. A high performance regulator conforming to EN250 will perform adequately and substituting an untested parameter to the safety equation is a hazardous practice. Testing that the BOV actually breathes without leaking is also not a substitute for testing the impact upon CCR WOB, of adding a potential restriction to a closed circuit breathing loop.

    All of this fanaticism about BOVs is deeply misplaced. Adding an untested piece of plastic to safety critical, life-support equipment, in the misguided hope that it will save your a** on a deep dive, as a replacement for a verified high-peformance regulator, is nothing less than monolithic stupidity.

    Great news that these guys assessed the situation and finished the dive. Why switch to a BOV, possibly connected to inboard gas in a non-physiologically compromising situation? Switching to a BOV connected to an in-board tank is an unnecessary action in this instance. It just means another step will be needed, that to a larger off-board tank. Even if the BOV was connected to the off-board bailout, why would you select an untested BOV in a high work-rate application, against the known quantity of a verified high performance breathing regulator? Swimming a fully flooded rebreather any distance is hard work and requires a decent inflation gas supply and a high performance breathing regulator.

    The right tools, used appropriately for the job, are more likely to save your life, than rigid conformance to the brain-washed masses' utopian "ideals".

    Regards

    AnneMarie
    Good grief!

    It proves that it's connected.

    It proves that the gas is on.

    It proves that it works.

    It proves that it's available immediately in an emergency

    And it builds muscle memory so that usage becomes automatic when hypercapnia hits.

    Anoither monolithically stupid thing that I did was to do a practice bailout from 220 ft. I'm just an idiot that way.

    So while you DON'T use a BOV and wait around for someone else to test it, I'll just go ahead and slob-knob something together on my own.

    BTW, why do you always expect someone else to do your checking for you? Life must be a nightmare - what safety standard have my shoe laces been tested to? Has this food passed sufficient agencies' safety standards? Eatuing a banana must be a logistic disaster for you.
    Last edited by aainslie; 31st July 2008 at 15:25.
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  5. #45
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    Re: 8000 Feet, One Spool and One Total Loop Failure

    Quote Originally Posted by mempilot  View Original Post
    Which was Andrews point of his check. Good, so you agree.

    You are the one missing the point completely, and are going off on a tangent.
    I agree with what? That statement I made is on the premise that the equipment has been tested appropriately for use as a high performance regulator, conforming to appropriate WOB requirements, to the limits of the target CCR equipment and tested to prove that it does not have a detrimental impact upon CCR WOB.

    So, no we don't agree, because you suggest that operational checks are sufficient. They are not, unless the equipment has also been stringently tested in accordance with the parameters of the target equipment and depth rating and WOB considerations.

    Where is the tangent? The crux of this discussion is whether or not someone should switch to their BOV instead of an OC bailout regulator. Furthermore, the primary discussion relates to whether or not a BOV should be the instant bailout choice in EVERY situation. Therefore, that proposition necessitates the underpinning discussion of whether or not a BOV is an acceptable substitution for a high performance regulator, in a variety of situations.

    Regards

    AnneMarie

  6. #46
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    Re: 8000 Feet, One Spool and One Total Loop Failure

    Quote Originally Posted by aainslie  View Original Post
    Good grief!

    It proves that it's connected.
    So?

    Quote Originally Posted by aainslie  View Original Post
    It proves that the gas is on.
    So?

    Quote Originally Posted by aainslie  View Original Post
    It proves that it works.
    Define "works". Under what conditions? Which breathing rate? What depth? Works without detrimentally impacting CCR WOB?

    Quote Originally Posted by aainslie  View Original Post
    It proves that it's available immediately in an emergency
    Is it? As opposed to what? A *tested*, *verified* high performance regulator? Will it "work" in the manner needed to save your life? What testing has determined it fit to perform this function?

    Quote Originally Posted by aainslie  View Original Post
    And it builds muscle memory so that usage becomes automatic when hypercapnia hits.
    At what depth? Where is it plugged into? Inboard? Small tank? And then what? At 100m you get a few breaths then still have to conduct an OC bailout. Plugged into mix offboard? Then what? What will you bail onto when shallow? An offboard OC regulator? Or will you automatically go to the BOV *every* time? That muscle memory will kill you if you automatically go to the BOV when at a depth where the BOV is plumbed to an inappropriate gas!

    Quote Originally Posted by aainslie  View Original Post
    Anoither monolithically stupid thing that I did was to do a practice bailout from 220 ft. I'm just an idiot that way.
    Did that practice bailout incorporate a full hypercapnia trial? If so, how did you simulate this? What was your RMV? Can you provide objective metrics relating to the BOV's WOB characteristics and how they conform to the performance required to discharge a severe physiological event? What did that practice bailout really prove?

    Quote Originally Posted by aainslie  View Original Post
    So while you DON'T use a BOV and wait around for someone else to test it, I'll just go ahead and slob-knob something together on my own.
    I have BOV test results in front of me as we speak and I don't mean some "practice bailout" results. So many assumptions...I am not saying don't use a BOV, I am saying be aware of the implications of doing so and particularly the implications of doing so, if untested and as a substitute for a known quantity, that of a high performance regulator.

    In any case, the question remains, what is the appropriate plumbing solution for the BOV, if it is going to become a muscle memory to always switch to it. If you dive hypoxic diluent inboard and connect BOV to inboard, are you going to switch to BOV automatically during an event which occurs at the wrong depth for the gas the BOV is hooked up to and then become hypoxic? As opposed to bailing out onto an OC regulator connected to an appropriate gas?

    A practice bailout proves nothing, except that by the very premise of adding a non-formally tested piece of equpment, as a substitute for a known high performance regulator, that you are happy to be a guinea pig the day you need to effect a bailout in a *real life, real world physiological event* where your life depends upon that *untested* but "operational" equipment.

    Regards

    AnneMarie

  7. #47
    So Cal Tech Diver aainslie has a reputation beyond repute aainslie has a reputation beyond repute aainslie has a reputation beyond repute aainslie has a reputation beyond repute aainslie has a reputation beyond repute aainslie has a reputation beyond repute aainslie has a reputation beyond repute aainslie has a reputation beyond repute aainslie has a reputation beyond repute aainslie has a reputation beyond repute aainslie has a reputation beyond repute aainslie's Avatar
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    Re: 8000 Feet, One Spool and One Total Loop Failure

    OK, I give in to your sheer speed of typing skills.

    You fumble around trying to put a highly tested reg into your mouth (if you can even bring yourself to remove the mouthpiece). I'll take my chances rotating a knob 90 degrees.

    How much "carefully tested" results do you ahve of the relative risks of the BOV's ability to deliver gas vs a diver's ability to take a mouthpiece out nad put a reg in during a hypercapnia event? Any? At all?

    No point testing the heck out of something that may never make its way into a diver's mouth.

    Good luck with your ISO blah blah tested reg.
    Andrew Ainslie

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  8. #48
    RBW Member mempilot has a reputation beyond repute mempilot has a reputation beyond repute mempilot has a reputation beyond repute mempilot has a reputation beyond repute mempilot has a reputation beyond repute mempilot has a reputation beyond repute mempilot has a reputation beyond repute mempilot has a reputation beyond repute mempilot has a reputation beyond repute mempilot has a reputation beyond repute mempilot has a reputation beyond repute mempilot's Avatar
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    Re: 8000 Feet, One Spool and One Total Loop Failure

    Quote Originally Posted by AM  View Original Post
    That statement I made is on the premise that the equipment has been tested appropriately for use as a high performance regulator, conforming to appropriate WOB requirements, to the limits of the target CCR equipment and tested to prove that it does not have a detrimental impact upon CCR WOB.

    Where is the tangent?

  9. #49
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    Re: 8000 Feet, One Spool and One Total Loop Failure

    Quote Originally Posted by AM  View Original Post
    You are missing the point completely. Operational checks verify that equipment ...............................Certification is a different matter entirely.

    Regards

    AnneMarie
    So, are you saying you DO NOT use a BOV becuase it they are neither tested nor "high perfermance"?

    Or

    Are you saying you DO use a BOV but you wish they were tested and high performance?

    Or

    Are you saying something else, 'cos frankly I am sure everyone agrees that certification testing is a GOOD thing generally - but if tested kit is not available, can't be used or you prefer something else, you have to run with what's available and use your noggin.......and, it seems to me that most people on this post seem to (a) have a noggin and (b) understand the risks.......and (c) already understood the gist of your lecture....

    Seems to me the risk of a hypercapnea episode killing you is greater than the risk of an well maintained but uncertified BOV not performing, especially as the most popular BOVs use high performance (and incidentally CE tested) components.

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