Ways to Improve CCR Safety (System Wide)...

[alexasigno]

I think everyone has debated standards and protocols enough, and nothing more is going to come out of it. Perhaps this would be more constructive if we start aligning where we agree with each other.

I'll start:
1) RBs are dangerous but accept that risk
2) This risk can be made lower - I'm sure most of us have modified our unit in some way to improve safety for the type of dives we are doing
3) A device could be made simple and cheap enough to detect a missing scrubber
4) No company should ethically or legally be able to make claims over RB vs OC without third party pier reviewed papers
5) All claims from manufacturers should be backed up with publicly available data

Anything else?

 

[gianaameri]

I think everyone has debated standards and protocols enough, and nothing more is going to come out of it. Perhaps this would be more constructive if we start aligning where we agree with each other.

I'll start:
1) RBs are dangerous but accept that risk
2) This risk can be made lower - I'm sure most of us have modified our unit in some way to improve safety for the type of dives we are doing
3) A device could be made simple and cheap enough to detect a missing scrubber
4) No company should ethically or legally be able to make claims over RB vs OC without third party pier reviewed papers
5) All claims from manufacturers should be backed up with publicly available data

Anything else?

6. No company/person/third-party should claim that a life-support rebreather product for recreational purposes meets "EN14143:2003" when it does not (i.e. if it lacks of all things Functional Safety).
7. If a product lacks the Functional Safety prescribed by the current standard, then it should state clearly so on the product, and user informed consent ought to be obtained prior to the sale and/or use.

 

[Mr Walker]

3) A device could be made simple and cheap enough to detect a missing

There already is one - the tempstick. If you prebreathe your unit it will also warn if there is no scrubber material that reacts.

/nils

 

[alexasigno]

Yes it's a nice aid, but doesn't alarm you that there is no scrubber. In the case of the recent fatality it would likely not have solved anything.

 

[MeRodent]

C. You claim that it meets "EN14143:2003" when it does not (i.e. you have taken a shortcut and circumvented the requirement so it cannot meet EN14143:2003, but yet you claim it does)

This got missed in the move so I thought I'd reply here.

The point is Gian that you say that rebreather manufacturers claim they have passed EN14143:2003 because they are certified to CE. The question I asked is "Do any manufacturers claim (falsely) that they have passed EN14143:2003?"

I understand that this is a difficult question as it requires a yes/no answer but I would love to have your response.

Please understand that it would be great to have a rebreather that has a higher level of safety but it seems the rest of us live in the real world and don't see a conspiracy to kill divers in order to make a profit from the manufacturers of rebreathers as this would tend to be counter-productive in the small market that CCR comprises.

 

[Mr Walker]

Yes it's a nice aid, but doesn't alarm you that there is no scrubber. In the case of the recent fatality it would likely not have solved anything.

Kind of subjective - to me it's a clear alarm if the tempstick doesn't show up.

Anyway, if such a device was to be implemented in the Disco I',m sure it would also come with a change in the software. I believe it would result in a definite alarm followed by a "NO DIVE". Come to think of it, it would probably be really easy to do in my Vision as well.
And I prefer this solution over (spring loaded?) valves that closes gas flow. If a valve like that failes closed during dive... not funny...

/nils

 

[alexasigno]

I agree with the gas flow, don't think we need a physical device to stop gas. Just a warning on the screen *should* be enough.

 

[Mr Walker]

I prefer the "If you can't remember to put the scrubber in, you shouldn't be diving a rebreather" method.

If PADI exited the rebreather market, that would improve safety as well. They've already fcuked up the Inspo with their insistence on "wet contacts"!

I agree that this should be enough. If there's no scrubber - it's not a rebreather, sort of. However, as shown, it's not always enough...

But my tempstick is already there so... a small change in the software would have my liking.

Wet contacts, now thats a degradation.

/nils

 

[Mark Chase]

I think everyone has debated standards and protocols enough, and nothing more is going to come out of it. Perhaps this would be more constructive if we start aligning where we agree with each other.

I'll start:
1) RBs are dangerous but accept that risk
2) This risk can be made lower - I'm sure most of us have modified our unit in some way to improve safety for the type of dives we are doing
3) A device could be made simple and cheap enough to detect a missing scrubber
4) No company should ethically or legally be able to make claims over RB vs OC without third party pier reviewed papers
5) All claims from manufacturers should be backed up with publicly available 4ata

Anything else?

1: Totaly remodel the way CCR is taught
2: Totaly remodel the way CCR is taught
3: Totaly remodel the way CCR is taught
4: Totaly remodel the way CCR is taught
5: Totaly remodel the way CCR is taught


All I want from manufacturors is proper WOB test data on fixed test peramiters and the same for scrubber duration.

Id like to see Air @ 40m and 14/65 at 70m


Id also like to see TWO POINT scrubber duration test data for realistic SACs


SAC 30LPM 40m 5c
SAC 30LPM 40M 15c


In an ideal world id like to see all manufacturors contributing to a single reserch fund for C02 monitoring and 02 cell replacement / improvement

To my mind Sheerwater have provided a solid platform for electronics which is being widly used and again i see single funding of R&D on a single electronics package to be the only way forward in order to overcome the massive cost of CE and product testing for such a small end user market.

Oh look, a flying pig. :sigh:


ATB

Mark

 

[alexasigno]

On to scrubbers, is there any research on storage time between dives?

 

[Mark Chase]

6. No company/person/third-party should claim that a life-support rebreather product for recreational purposes meets "EN14143:2003" when it does not (i.e. if it lacks of all things Functional Safety).
7. If a product lacks the Functional Safety prescribed by the current standard, then it should state clearly so on the product, and user informed consent ought to be obtained prior to the sale and/or use.

Could i propose banning anyone who even mentions the phrase EN14143:2003from all internet diving forums.

Then we should hang any MD from a manufacturor who claims EN14143:2003 who then has a diver die on their unit because he trusted the unit to keep him alive (bassed on safety claims he didnt understand) rather than taking responsibuility for his own fate

:rocker::rocker::rocker:

Vote Chasey for President and Ill also exicute all "no win no fee" ambulance chasers :rocker:

ATB

Mark

 

[ebt]

On to scrubbers, is there any research on storage time between dives?

Canadian navy, its on Rubicon

 

[alexasigno]

Just read that interesting, would like to see it for longer durations and multiple dives.

 

[le parpaing]

I prefer the "If you can't remember to put the scrubber in, you shouldn't be diving a rebreather" method.

Sh**!! I am of that kind. That's why I use a paper checklist with only two rules to remember
1) tick only when the item is completely ok
2) don't go diving until the checklist is complete
So many times, I have seen experienced divers, including instructors forgetting to close their drysuit, to take their fins, to open their tanks...

I do not pretend to know The Truth and to say what is OK or what is not. I just mean, each of us has his/her own way to get ready for a dive. Like security parameters on your computer, the choice is somewhere between the tightest and the loosest rules. And those definition of tigh security rule vs loose security rules are STRICTLY synonyms with "boring" and "dangerous", respectively. So, as a father and husband, my religion is the "boring" side:big:

 

[Mike Ferguson]

And I prefer this solution over (spring loaded?) valves that closes gas flow. If a valve like that failes closed during dive... not funny...
QUOTE]

Depends on the final design solution and a fail close valve would be worse than no valve, if a valve/ flapper is held open by the pysical presence of the scrubber it couldn't really fail closed but the easiest fix is an interlock that prevents you closing the lid without a scrubber in place. If an interlock is designed in before tooling is made the cost is peanuts.

FFS my food processor has an interlock that means I can't switch it on without the lid so I can't absent mindedly stick my fingers in when task loaded by simultaneously cooking and sampling the wine, and I seem to recall having a fishtank filter that couldn't be closed and sealed if the filter element was missing. Yet I can leave out quite possibly the most fundamental part of the breathing loop that keeps me alive on my rebreather and then do a perfect positive and negative pressure test and calibration and have a load of green lights telling me everything is fine.

Run that through any simple risk assessment process.

Risk - scrubber omitted in pre-dive assembly and not detected in pre-dive checks
probability of diving without scrubber in place - possible
potential consequence of diving without scrubber in place - Death
mitigation - training and CYA warning in book
residual probability of diving without scrubber in place - very unlikely
residual potential consequence of diving without scrubber in place - Death

vs

Risk - scrubber omitted in pre-dive assembly and not detected in pre-dive checks
probability of diving without scrubber in place - possible
potential consequence of diving without scrubber in place - Death
mitigation - not possible to assemble unit without scrubber
residual probability of diving without scrubber in place - zero
residual consequence - time delay and embarrasment

 

[Mr Walker]

And I prefer this solution over (spring loaded?) valves that closes gas flow. If a valve like that failes closed during dive... not funny...
QUOTE]

Depends on the final design solution and a fail close valve would be worse than no valve, if a valve/ flapper is held open by the pysical presence of the scrubber it couldn't really fail closed but the easiest fix is an interlock that prevents you closing the lid without a scrubber in place. If an interlock is designed in before tooling is made the cost is peanuts.

FFS my food processor has an interlock that means I can't switch it on without the lid so I can't absent mindedly stick my fingers in when task loaded by simultaneously cooking and sampling the wine, and I seem to recall having a fishtank filter that couldn't be closed and sealed if the filter element was missing. Yet I can leave out quite possibly the most fundamental part of the breathing loop that keeps me alive on my rebreather and then do a perfect positive and negative pressure test and calibration and have a load of green lights telling me everything is fine.

Run that through any simple risk assessment process.

Risk - scrubber omitted in pre-dive assembly and not detected in pre-dive checks
probability of diving without scrubber in place - possible
potential consequence of diving without scrubber in place - Death
mitigation - training and CYA warning in book
residual probability of diving without scrubber in place - very unlikely
residual potential consequence of diving without scrubber in place - Death

vs

Risk - scrubber omitted in pre-dive assembly and not detected in pre-dive checks
probability of diving without scrubber in place - possible
potential consequence of diving without scrubber in place - Death
mitigation - not possible to assemble unit without scrubber
residual probability of diving without scrubber in place - zero
residual consequence - time delay and embarrasment

That would work. Preventing the lid from closing without a scrubber is also a very cheep solution, I believe. This should be implemented in all units (new units) since it wont affect cost in any significant way. Older units will have to have the entire canister exchanged for new so it will have to be at the divers choice if he's willing to spend the money.

However, the tempstick takes it one step further since it also has the benefit of telling if there's scrubber material in the scrubber. You prebreathe (by the units demand even?) until reaction in the lime is detected and the first bar shows up in the display. If this doesen't happen you get a "NO DIVE". Which of course will mean that a unit like this wont let you dive without proper prebreathe. It also means that the lime has to be fresh enough to start a reaction. Kinderegg, kind of...
More expensive than the lid solution but way better IMHO.

Anyway, this is what we do.

/nils

 

[Mr Walker]

The Sentinel has EN14143:2003 mentioned all through it's manual & who it's design exceeds CE requirements. On paper it's a very good unit, but I found it a bitch in the water, so flogged it & went back to an Inspo

The Sentinel as part of it's pre-dive checks makes you breath the scrubber for 5mins & the software checks for a temperature gradients across the stack. A fresh scrubber gets there in ~3mins but you still have to do the additional 2 mins. A used scrubber can take the full 5 mins to satisfy the system.

However:

1) You can press ABORT, you get a warning screen but then system will work as normal (did this many times)

2) Even if you complete the tests & system says NO-DIVE, if you jump in the system will still do it's best to function & keep you alive . So I'm not sure how the statement:


.... stacks up (sorry for the pun).

Yes, true of course. But if Poseidon were to implent it I'm sure there wouldn't be any "ABORT" option available.

And the unit doing it's best even if you don't is probably a good thing.

So I still think the tempstick is the best or most complete solution as of today.

BTW, the price of a tempstick is £306.38 inc. VAT and £255.32 exc. VAT.
I think it's worth it, others might not.

/nils

 

[Ben Field]

I prefer the "If you can't remember to put the scrubber in, you shouldn't be diving a rebreather" method.

Amen.

It should be in the checklist, just added it to mine-
1. Remove Head from sand
2. Put scrubber in unit
3. Assemble everything else properly
4. Test, Calibrate and pre-breath
5. Dive

 

[heyydude]

Could i propose banning anyone who even mentions the phrase EN14143:2003from all internet diving forums.

Then we should hang any MD from a manufacturor who claims EN14143:2003 who then has a diver die on their unit because he trusted the unit to keep him alive (bassed on safety claims he didnt understand) rather than taking responsibuility for his own fate

:rocker::rocker::rocker:

Vote Chasey for President and Ill also exicute all "no win no fee" ambulance chasers :rocker:

ATB

Mark

Dude,

You have my vote. "President Chasey"... Can I be in charge of the Nukes??

:-D

Kevin.

 

[Randy Thornton]

Vote Chasey for President and Ill also exicute all "no win no fee" ambulance chasers :rocker:

You have my support Sir! :rocker: