Fatality on Mk VI in Portugal - April 2013

[gianaameri]

........and its something a 5 minute pre breathe would detect, so again another example of diver error.

No pre-breathe, diving Solo in Open Water... sure, more User Error.

However, there has been no formal study to show a 5 min. pre-breathe is effective in detecting a missing or faulty scrubber.



Sent from my HTC Desire C using Tapatalk 2

 

[AD_Ward9]

I am still waiting to here from Alex (but in fairness not expecting an answer) about how much it would have cost DL/OSEL to have put the APOC through the same certification as the mil/commercial units which APOC uses spin-off technology from. I am guessing that it is unsustainable for a recreational unit. Whilst you are developing and building a new unit you need to be aware of how you are going to test and accept it given the market forces which are out there. I am pretty certain that the end user has no concept of how much it costs to test equipment to meet the high reliability/safety figures that they think are easily achievable. That doesn't mean that they shouldn't be the stretch goal, but if you are marketing into a sport (especially the recreational end of the market) you need to make it cheap.

Regards

GLOC, you simply can't make it cheap as doing so will kill divers as is shown in the accident stats and studies.

The cost of certifying the Apoc was the same as certifying the military/commercial units as they need to meet the same EN14143:2003 standard for CE.

To make this commercially viable, we developed one set of interchangeable components to make the three different breathing loops (front mount, rear mount, and rear mount twin scrubber), and worked with three different clients who address the sports, military and commercial diving markets respectively. There are considerable differences to the controllers between these applications but the breathing loops are the same. The components are interchangeable between these loops. In fact, we could use any of the three loops in any of the three applications, depending on what clients require.

One has to put the CE costs in the context of a professional project. CE certification, including IEC 61508, came to 3 million Euro (1 million originally planned plus 2 million over two years for the strict rigour from the UKAS NB audit). There were three rebreather loops so one could amortise that as original expectation of 300K Euro per rebreather cert cost, and 1 million actual. The design and tooling came to 3.5 million, with research prior to that being another million Euro. So 7.5 million Euro for the whole thing.

These costs are not out of order and not unique to DeepLife/OSEL: I note the public announcements of investment into a sports rebreather company last year was 14 million Euro, and rebreather company being sold for 35 million. If a company wants to get a return on its investment putting in 14 million, then it will need to cover multiple markets, or sell a heck of a lot of products. This should drive down the cost of rebreathers to bring up volume.

With all the design and tooling in place we can now do new rebreather models, using the same modules and subsystems, at around 600K Euro each and could do the entire set of tests for CE for around 300K Euro (about 10% of the cost of setting up all the test systems, using independent agencies etc, manning and running the original tests, the first time around). That capability is also worth a lot.

Alex

 

[GLOC]

Gian, you accuse me of being theoretician and not an operator!. Whilst you are correct that there is no formal work presented regarding the efficacy of a 5 min-breathe to detect faulty scrubber or scrubber breakthrough. Jeff Bozinac did present something (not validated) at RF3.0 testing this scenario - I need to check my notes but think that 5 mins wasn't enough to detect breakthrough. Notwithstanding this, 5 mins breathing a loop properly (occluded nose) with no scrubber at all will more than likely show that something is wrong.

I am on my phone at the moment so can't check but I am sure that pre-breathe is not in the pre-dive check for MK VI (for whatever reason) and therefore an error of omission can't be attributed if it wasn't in the task list to be completed. The reasons that people used to cite for pre-breathing (scrubber material initiation) have not been validated and this might be why it is not in the MK VI manual (caveat above).

Regards

 

[Michael Thornton]

Whilst you are correct that there is no formal work presented regarding the efficacy of a 5 min-breathe to detect faulty scrubber or scrubber breakthrough. Jeff Bozinac did present something (not validated) at RF3.0 testing this scenario - I need to check my notes but think that 5 mins wasn't enough to detect breakthrough. Notwithstanding this, 5 mins breathing a loop properly (occluded nose) with no scrubber at all will show that something is wrong.

I remember this presentation at RF3. I do not remember him ever saying that they were doing a nose blocked prebreathe. (I could be wrong he may have said that) I just don't remember it. I would like to see a video of someone doing a NOSE BLOCKED prebreathe for 5 mins with no scrubber and not be able to notice something is off. I might have an easier time believing it then.




Sent from my iPhone using Tapatalk

 

[alexasigno]

Volunteer anyone?

 

[GLOC]

Sorry, should have said 'very likely' not 'will'.

I don't have a CCR so can't test it...but there are plenty 'scientists' out there (at your own risk )

Regards

 

[gianaameri]

Gian, you accuse me of being theoretician and not an operator!. Whilst you are correct that there is no formal work presented regarding the efficacy of a 5 min-breathe to detect faulty scrubber or scrubber breakthrough. Jeff Bozinac did present something (not validated) at RF3.0 testing this scenario - I need to check my notes but think that 5 mins wasn't enough to detect breakthrough. Notwithstanding this, 5 mins breathing a loop properly (occluded nose) with no scrubber at all will show that something is wrong.

I am on my phone at the moment so can't check but I am sure that pre-breathe is not in the pre-dive check for MK VI (for whatever reason) and therefore an error of omission can't be attributed if it wasn't in the task list to be completed. The reasons that people used to cite for pre-breathing (scrubber material initiation) have not been validated and this might be why it is not in the MK VI manual (caveat above).

Regards

5 minute pre-breathe works to verify a number of things, but Operators know is of limited effectiveness in saving life when it comes to a missing scrubber.

Nonetheless, a formal study by theoreticians would be required before manufacturer/training agency statements are made as to the procedure effectiveness in relations to CO2

Sent from my HTC Desire C using Tapatalk 2

 

[alexasigno]

I'd like to see this, but not volunteer. Perhaps taking off cylinders and walking around would be a good equivalent of co2 exertion as diving. I'm not confident 5mins would be enough?

 

[opheim]

However, there has been no formal study to show a 5 min. pre-breathe is effective in detecting a missing or faulty scrubber.

Easy. Set up your Meg, leave the scrubber out and breathe it for 5 minutes, making sure to pinch your nose or wear a mask. Let us know how it went.

PS: You may want to sit down for this exercise, and preferrably have someone else present to pick you up and remove the mouthpiece.

High PO2 might mask some of the elevated CO2 symptoms, so you may not feel anything before the lights go out.

There's no doubt in my mind that if the guy had done his recommended prebreathe, this accident would not have taken place.

That being said, the matter of a faulty scrubber is different. But I imagine it would be hard to study since the term "faulty" is pretty vague, and comes in all different shapes and colors. Some faults might be discovered, others might not. Still, a good prebreathe is just mandatory in my book, no ifs or buts - just do it. Every time.

 

[alexasigno]

That brings the next question. I'm not sure where the thermometer goes, so this may not be relevant. But What temperature does the scrubber need to get to? And would this temperature be possible by pre breathing without a scrubber?

 

[GLOC]

5 minute pre-breathe works to verify a number of things, but Operators know is of limited effectiveness in saving life when it comes to a missing scrubber.

Nonetheless, a formal study by theoreticians would be required before manufacturer/training agency statements are made as to the procedure effectiveness in relations to CO2

Sent from my HTC Desire C using Tapatalk 2

So, the solution is to either engineer the problem out or teach someone how to not screw up in the first place, hoping that the knowledge stays in their head.

How do operators know? Because someone hasn't done a formal study? Ethical issues are an issue when doing formal studies because you are potentially injuring someone. Have NEDU done this work? Probably not because they likely consider protocols the answer to mitigate the problem of a lack of scrubber material but I know they are fallible from an incident I know of. Risk benefit case would likely have been done regarding research required and decided against it.

Something to bear in mind is someone has to pay for this and sport divers, in general, do not prioritise additional safety equipment over other aspects of sport diving. Risk and risk perception...

Regards

 

[gianaameri]

Easy. Set up your Meg, leave the scrubber out and breathe it for 5 minutes, making sure to pinch your nose or wear a mask. Let us know how it went.

PS: You may want to sit down for this exercise, and preferrably have someone else present to pick you up and remove the mouthpiece.

High PO2 might mask some of the elevated CO2 symptoms, so you may not feel anything before the lights go out.

There's no doubt in my mind that if the guy had done his recommended prebreathe, this accident would not have taken place.

That being said, the matter of a faulty scrubber is different. But I imagine it would be hard to study since the term "faulty" is pretty vague, and comes in all different shapes and colors. Some faults might be discovered, others might not. Still, a good prebreathe is just mandatory in my book, no ifs or buts - just do it. Every time.

Done that as part of my course, but floating holding on the boat and finning under instructor supervision.

Our physiological response to CO2 may differ submerged at 0.7 pPO2 or higher vs. breathing air with a bit of CO2 on land.

Done the scrubber OUT test sitting in the garage and my Homebuilt CO2 Monitor was very effective at detecting no scrubber User Error.

Poseidon does not believe in inhale CO2 Monitors?

P.S. I no longer use inhale side CO2 Monitors.

Sent from my HTC Desire C using Tapatalk 2

 

[gianaameri]

So, the solution is to either engineer the problem out or teach someone how to not screw up in the first place, hoping that the knowledge stays in their head.

How do operators know? Because someone hasn't done a formal study? Ethical issues are an issue when doing formal studies because you are potentially injuring someone. Have NEDU done this work? Probably not because they likely consider protocols the answer to mitigate the problem of a lack of scrubber material but I know they are fallible from an incident I know of. Risk benefit case would likely have been done regarding research required and decided against it.

Something to bear in mind is someone has to pay for this and sport divers, in general, do not prioritise additional safety equipment over other aspects of sport diving. Risk and risk perception...

Regards

Very cheap to engineer out a no scrubber risk at the design stage.

Very expensive/difficult to do it after it is too late.

Poseidon just did not think this could happen, but it did.

Sent from my HTC Desire C using Tapatalk 2

 

[GLOC]

Alex,

Thanks for providing those figures for your theoretical rebreather, I say it this way because there is nothing on the market to buy and I do not want this thread to show that you can do something and bring it to market when nothing is actually there.

As you have nothing to market, there are likely to be additional costs to the ones above and the 2nd tranche of savings are only there if you have a second system to market and sell.

I don't want to get into the mud-slinging that will likely develop re: a PDF based CCR, but you do show the concept that by having additional markets it is possible to leverage savings across the certification requirements. Until the CCR is available, it is all theory.

There's no doubt in my mind that if the guy had done his recommended prebreathe, this accident would not have taken place.

The problem with making statements like this, is the assumption that a pre-breathe is required and has been taught to the User. If it doesn't detect faulty scrubber packing (pre-packed scrubber canister set up, so packing shouldn't be an issue) and there is no temp stick monitoring on the scrubber side to detect chemical reactions, why do a pre-breathe if the system has already tested pos- and neg- pressures during the start cycle? The assumption being that the user followed the advice in installing the unit together correctly? When looking at causality you need to consider the training that the diver had been given. Missed scrubber installation, should have fitted it. Error. Didn't pre-breathe, not taught in training as not part of syllabus. Did do a pre-breathe. Not an error in what they should have done. This is the problem I am having in identifying violations or errors because there are so many variations of what is taught and what should be taught (logically or as part of a training package). You can't accuse the user of not following his teaching if he was never taught it.

Edit: Corrected. The pre-dive checklist covers a 4 min pre-breathe with pinched nose.

Regards

 

[Mr Walker]

With the Inspo (or any other RB) fitted with a tempstick you get the first warning during startup testing; tempstick present or not present.

If tempstick is present there is also a canister in the bucket. Great.

Then if you prebreathe ~5mins you will see the first block in the tempstick graph show up thus indicating there is also scrubber material in the canister. Super.

I'm happy with this. I'm actually really fond of my tempstick as it serves several purposes.

But I wouldn't say no to a CO2 sensor if available and reasonably priced.

/nils

 

[gianaameri]

Alex,

Thanks for providing those figures for your theoretical rebreather, I say it this way because there is nothing on the market to buy and I do not want this thread to show that you can do something and bring it to market when nothing is actually there.

As you have nothing to market, there are likely to be additional costs to the ones above and the 2nd tranche of savings are only there if you have a second system to market and sell.

Not theory because the Notified Body has actually issued the Certificates (for what Certificates are worth).

So, the products exist and have been tested by the Notified Body.

It is just that we cannot assess if a SIL 3 rebreather lives to its expectations till it is released.

However, proof that a product can be designed, built, and certified to SIL one and above does exist.

In any event, the issue with the OP seems to be that the MKVI marketing did not disclose (i.e. labels, warnings, information...) clearly enough the lack of conformance to that which otherwise the APOC conforms to as evidenced by the Certification.

 

[GLOC]

I have managed to look through the manual and found this

The manual does cover pre-breathe for 4 mins in the Pre-Dive Checklist on page 47.

Apologies for questioning the assumption above, but the premise remains the same. You can't criticise someone for not doing something when they did not know they had to.

Regards

 

[gianaameri]

I have managed to look through the manual and found this

The manual does cover pre-breathe for 4 mins in the Pre-Dive Checklist on page 47.

Apologies for questioning the assumption above, but the premise remains the same. You can't criticise someone for not doing something when they did not know they had to.

Regards

Is it a fact that the diver in this incident did not know he had to do a 4 minute pre-breathe?

Would a 4 minute pre-breathe detect a no scrubber User Error (or is it there for another purpose like doing other pre-flight checks)?

 

[opheim]

The problem with making statements like this, is the assumption that a pre-breathe is required and has been taught to the User. If it doesn't detect faulty scrubber packing (pre-packed scrubber canister set up, so packing shouldn't be an issue) and there is no temp stick monitoring on the scrubber side to detect chemical reactions, why do a pre-breathe if the system has already tested pos- and neg- pressures during the start cycle? The assumption being that the user followed the advice in installing the unit together correctly? When looking at causality you need to consider the training that the diver had been given. Missed scrubber installation, should have fitted it. Error. Didn't pre-breathe, not taught in training as not part of syllabus. Did do a pre-breathe. Not an error in what they should have done. This is the problem I am having in identifying violations or errors because there are so many variations of what is taught and what should be taught (logically or as part of a training package). You can't accuse the user of not following his teaching if he was never taught it.

Absolutely correct, Gareth. However, the predive checklist from Poseidon (found in the user manual at page 47, point 20);

Prebreathe. It is very important to preform a full prebreathe for a minimum of 4 minutes, while pinching your nose.

It would be rather strange if a diver received training that did not comply with Poseidons recommendations, wouldn't it?

(EDIT: You're too fast... Realized this had also been noticed while I was finding the link... )

 

[Igor]

Tested my JJ without scrubber sitting down on a bench. It took 2-3 min before first symptoms. After 3-4min it was terrible with high breathing rate, dizziness ,headache and generally feeling really horrible. A 3min pre breath is a bit short as the Co2 symptoms seem to turn up after 2-3 min but i think a 5 min pre breath will work well.