rebreather death edo-04 (rb 80 clone)

[padiscubapro]

posted on another list

Reinhard Buchaly schrieb:
>
>
> About two weeks ago a diver died using the EDO 04, after he had purchased
> the rebreather a week ago.
>
> The public prosecutor requested that I do an expertise of the unit of the
> deseased. I did so in the presense of a police man.
> Both units had the same failure point. This failure can kill a diver.
>
> Because not all users of the rebreather EDO 04 are known and cannot be
> informed by the public prosecutor, this warning is done via the usual e-mail
> lists.
> If anybody knows a user of the rebreather EDO 04, he should give him this
> notice as fast as possible.

On www.thueringen.de/de/lka/aktuell/presse/pm/10774/uindex.html there is
shown what the police thinks to have been the cause of the acident. Pics
show a badly warped checkvalve, which may have been leaking, or stuck
closed.

Imho redundancy and/or a more reliable checkvalve( like one with mica
disk) would have prevented an accident ( if stuck, not if one was
leaking)

 

[caveseeker7]

The German message boards have been aflame with this accident. Thanks for the link to the LKA's (state police investigators) official version. Makes sense they asked Buchaly to be an expert witness as the EDO is a copy of the RB 80. And Reinhard Buchaly is the RB. Buchaly's dive partner, 'db8us' Waldbrenner, pointed out a while ago that the quality & materials used in the EDO were inferior to the RB80. No kidding.

The deceased was on his 4th dive with the unit, solo, not having received certification (if there is any, or training for that matter). Not the way to go.

From other reports he was diving in about 20m when fishermen and other people lakeside realized the dive light stopped moving. When they tried to get help from the local base/shop, they were sent away and ended up calling authorities themselves.

Sad incindent.

 

[pwfletcher]

Does that unit have any elcectronics that monitor O2 levels? If not, do you think that it may have saved the diver if it had such monitoring devices?

 

[caveseeker7]

pwfletcher once bubbled...
Does that unit have any elcectronics that monitor O2 levels?

No, the EDO04 not only comes without monitoring device (such as an Oxygauge), but unlike the RB80 it doesn't even have a sensor port to put one in. Major mistake in my book. The guy could, however, rigged something fairly easy. The EDO04 has Dräger breathing hoses, so he could have used an Oxy2 (dual O2 cells) for monitoring. Those however are supposed to be used with the Uwatec ZO2, which calculates nitrox, not helium.
The guy was a caver, had a dual rig, might well have wanted to use it with trimix or heliox ...
He could have fit a VR3, Explorer, or Oxygauge, in there, too, with some drilling and the P-connector.
But from what I understand even the RB80s are used without O2 monitoring, unless for training purposes to show students just how little the O2 drops (in comparisson to CMF units). Not my kind of thinking, but the DIR boys don't like electronics much, and I guess another used port is another potential failure point.
The RB80 has an excellent track record, but if I remeber right quite a few cave dives have been done on EDO04s in Europe, some of them pretty deep penetrations.

 

[caveseeker7]

pwfletcher once bubbled...
If not, do you think that it may have saved the diver if it had such monitoring devices?

Probably if not likely. If you look at the pictures Padiscubapro's link leads you to, you can see the deformed one-way valve. That's the one that keeps the gas that flows into the small, inner bellows from returning into the loop. That's the gas that is supposed to be released, and then replaced by fresh gas from the tanks. Gas addition is triggered by a pair of rods when the bellows 'bottoms out'.
If the breathed gas in the inner bellows gets back into the loop because of a faulty one-way valve, or a leak in the bellows, no new gas will be added. The same gas is then rebreathed until O2 levels are too low to sustain life. Kinda like a CCR without O2 addition. He broke the 1st rule: ALWAYS KNOW YOUR PO2!
I haven't had a chance to try the RB80, but Waldy said you can hear the gas addition easily. He and Madmole were talking about this sort of leak as a potential failure point in RB80s. So the divers inexperience on the unit (his 4th dive), and maybe lack of training/knowledge (he didnlt know what to look and listen for) might have been a contributing factor. Pre-dive checks on the day of the accident I don't know about.
While they haven't finished the investigation, I'm pretty sure the valve as shown doesn't work as it is supposed to. If the diver died, as they currently believe, of hypoxia I'd say either O2 monitoring could have prevented the accident and/or a dive buddy could have saved the diver.

Madmole's quest for safer RB diving just got another sad example:
Never disregard the 1st rule and never dive solo on a(ny) rebreather.

 

[caveseeker7]

padiscubapro once bubbled...

Imho redundancy and/or a more reliable checkvalve( like one with mica
disk) would have prevented an accident ( if stuck, not if one was
leaking)

Did you write that, Padiscubapro, or is it part of Buchaly's post?
2 rebreathers seems redundant, and I assume he had OC bailout (there are two green hoses going out of the last picture that could well have 2nd stages on them. What's a mica disk?

My thought, how can a check valve end up like that, was answered when someone else asked the question on DiveOz. Jason McHatten had the same happening to the check valves of his MK15 when he cleaned them with hot water ... .
Something to think about when rinsing the loop.

 

[KentCe]

caveseeker7 once bubbled...
If the breathed gas in the inner bellows gets back into the loop because of a faulty one-way valve, or a leak in the bellows, no new gas will be added. The same gas is then rebreathed until O2 levels are too low to sustain life. Kinda like a CCR without O2 addition.

Of course testing those valves is part of the setup process (if you are DIR) and only takes a few seconds. After seeing those pictures I doubt I would ever forget that check.

 

[padiscubapro]

caveseeker7 once bubbled...

Did you write that, Padiscubapro, or is it part of Buchaly's post?
2 rebreathers seems redundant, and I assume he had OC bailout (there are two green hoses going out of the last picture that could well have 2nd stages on them. What's a mica disk?

No that portion was added by another fellow Matthias Voss, it seemed like a good assessment so I left it in place..
Mica is a mineral that when thin is flexible and resistant to high temperatures.. it can be used alone as a diaphram or as a backing to stiffen things up..

 

[db8us]

He "should" have noticed that the unit is not venting any gas at all.
But if you have no understanding of the unit, because nobody explained it you are lost.

Let´s assume the flapper valve failed from beginning of the dive...
On the way down everyhing seems normal, cause the CL will be squeezed by pressure and so the unit WILL inject.
So the diver thinks: ALL is OK.
The max depth was almost 20m, but he went upwards without any substantial bottom-time.
There he might have purged the unit through the nose and therefoe thinks: "All is OK" because when exhaling through the nose of course gas (purging the loop) is injected.

So now his dive was "almost over" and due to the fact that he was diving solo he relaxed and stayed in the warm shallow part of the lake (aroun 2mm) thats 6feet !!

There the **** hitted the fan, because he WAS NOT MISSING the sound of the venting and injecting.
Maybe because nobody told him about the importance or how exactly such a unit works.
As Caveseeker said fishermen notcied his light not moving....

A buddy could have just put him "on his feet" and would have saved his live.
A sad unnecessary loss....

Caveseeker is also right, they tried to save a buck wherever they could, so parts made out stainless steel on the RB80 where out of plastic, other instead of teflon-coated aluminium also out of plastic. The port for the Oxygauge left out...cheap Ray-hoses without integreated bailout mouthpiece...

The "manufacturer" has NOW 80 dives on the unit and yet is selling it since May.

How should they pass on knowledge and/or experience ?
They just did a bad copy without getting the full picture...

Michael

Of course there are laso pre-dive checks .....

 

[padiscubapro]

I never saw anything that said the unit wasn't venting ANY gas.. even as bad as those valves looked there was probably some fresh gas exchange, but it would be a losing battle the po2 would be gradually falling, if there was no exchange PO2 falls rapidly and symptoms may show themselves, a very slowly dropping po2 is more likely to first effect ones cognative ability, followed by unconsciousness then death.. the fact that it was sustaining life in deeper water leads me to believe he was getting some gas exchange, in 2m water the po2 drop would be fairly rapid as opposed to 20m.

If some gas was venting, it probably seemed to be working well.. its hard to judge volume just by sound.. its more like bubbles or no bubbles.. a total fauilure of the valve would be simple to spot, a leaky or intermittent valve could possibly be missed in predive checks.