co2 hits? bov or not

[Mark Chase]

Brad

We dont need a 350m rated solinoid non of us will ever go there. If you got a 150m rated one it would do more than 99.5% of us would ever need

If you think theres no market for the BOV then explain to me why I see Golum Shrimps on 50% of the non APD CCR out there and APD BOVS on 70% of the APD units

If the electronics are interchangable fro the deep unit to the standard unit, sell the standard unit now and supply it to those on the waiting list, it sounds like you have no excuse not too

Is it to expensie to admit you do have the full on APOC and supply it to those on the waiting list at the £1500 you sugested it would cost? Are you waiting for all those on the list to give up and ask for their money back?

We chose to buy the best available BOV we can find that fitrs out unit. I had TEC4 i sold it to pay for a JJ BOV I sold that to pay for a Golum I sold that to pay for a Golum Shrimp.

I was upgradeing all the time and ill upgrade further if the right unit becomes available.

Divers are kit tarts. If theres a shining example of kit available we will lust after it.

ATB

Mark

 

[silentbob]

Plenty of NEDU/QinetiQ reporting that the 62.5L/min for OC and 75-90L/min for CC flow rates exist for very valid reasons and are easily achievable during routine diving.

Interesting, I just recently did a 10 minute maximal swim OC with a rebreather on my back and three 80s clipped on to see what my SAC rate would be for near worst case BO.

I could not have finned any harder and it took me a long time to regain my normal breathing rate after the test.

My SAC rate was 62 L/min. I have never worked that hard on a dive and would be happy to never have to again.

I have to say bullshit to any notion that this is a "routine" diving condition.

 

[Dave1w]

Interesting, I just recently did a 10 minute maximal swim OC with a rebreather on my back and three 80s clipped on to see what my SAC rate would be for near worst case BO.

I could not have finned any harder and it took me a long time to regain my normal breathing rate after the test.

My SAC rate was 62 L/min. I have never worked that hard on a dive and would be happy to never have to again.

I have to say bullshit to any notion that this is a "routine" diving condition.

Did the same last week, got to about 60 odd as well. Not normal or routine....


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[Mr fish]

OSEL is not a training agency. OSEL mitigates the risk of supply of rebreathers direct to customers through supply of certified functionally safe rebreathers and notification of the risk to customers. Trainers provide training. A different protocol to what others use but when you take the real world actions of divers into account, not a demonstrateably unsafe one.

what a load of shite , you cover your own arse , big fooking deal , you change your BS each week , what happed to the easy wipe apox diving Manual,
fook me at one time deas was saying divers are to thick to play home build and no one was getting a unit with out training and no one was getting parts to but on his unit as he said all the other kit being made joe 90 and shearmycomputer and the like was all shite ,
Also remember him saying, soon as he became king of the world and PAKER MARTIN WAS DEAD he wood be GOING after the computer market ,

O and then he fooking woke up , and knocked out some pdf,s
ps
the wipe down book or was it a CD in the end was the biggist load of bollox printed to date , im happy your not doing training , if you were you would be by now sat on your arse with feek all to do , no ONE buying so no training ,

even your uk TRAINERTRAINER hide,s WHEN the name APOX DL OSEL OR DEA,S is in a thread ,

think its time you all fook off till next year , you have had you time for 2015

 

[Brad_Horn]

We dont need a 350m rated solinoid non of us will ever go there. If you got a 150m rated one it would do more than 99.5% of us would ever need

Mark, Inspos are rated for what dives to 100m. What do their buzzers implode at 150m? How do we know that, because in the real world divers do not always do what they ought to.
Remember that bit where I also mentioned the EN61508 certification requirement for the eCCR controller. That means that it needs to take into account the real world use based on analysis of passed events on other similar kit. Hence DLs accident list being maintained by them as the only available resource of its type.

If you think theres no market for the BOV then explain to me why I see Golum Shrimps on 50% of the non APD CCR out there and APD BOVS on 70% of the APD units

Mark, Only a fool would say that there was not a market for BOVs; they are a critical safety device for rebreathers. that I think we both agree should be fitted as a default.
As per the classic case study with Simon - where an "expert" does not care what the WOB of his BOV is as he does not know it - there is not a sufficient market (for BOVs with high performance WOB) for OSEL to offer a L-R flow ALVBOV.

If the electronics are interchangable fro the deep unit to the standard unit, sell the standard unit now and supply it to those on the waiting list

As I have said, this is in the works.

Is it to expensie to admit you do have the full on APOC and supply it to those on the waiting list at the £1500 you sugested it would cost? Are you waiting for all those on the list to give up and ask for their money back?

Those EAs with iCCR back-orders will be getting an extremely good deal. Even so, noting the included features the Type IV iCCR at full price, it is still priced extremely competitively compared to other units on the market. OSEL is honouring the EA price for the iCCR in every regard.
Very few iCCR EAs have cancelled compared to outstanding back-orders. Hence the current significant Apoc Type IV build that you can see in the images released by OSEL earlier in July.

We chose to buy the best available BOV we can find that fitrs out unit. I had TEC4 i sold it to pay for a JJ BOV I sold that to pay for a Golum I sold that to pay for a Golum Shrimp. I was upgradeing all the time and ill upgrade further if the right unit becomes available. Divers are kit tarts. If theres a shining example of kit available we will lust after it.

Mark, What is the one similarity between these 4 BOVs. You do not know the OC WOB of any of them and you went from known very good CC WOB with the JJ-BOV at 1.06J/L to unknown WOB with the GG ones. See my above point about market.

Heck if your really that keen to have a known high performance ALVBOV or BOV with left-handed flow, get another 999+ divers interested in a group buy, submit a commercial PO to OSEL and it can go from there.

 

[Mr fish]

Heck if your really that keen to have a known high performance ALVBOV or BOV with left-handed flow, get another 999+ divers interested in a group buy, submit a commercial PO to OSEL and it can go from there.

You have your numbers the wrong way round 666 would be better ,

 

[steady1570]

As per the classic case study with Simon - where an "expert" does not care what the WOB of his BOV is as he does not know it - there is not a sufficient market (for BOVs with high performance WOB) for OSEL to offer a L-R flow ALVBOV.

This is disingenuous at best. I don't think you can say from anything that Dr Mitchell or others have written that they "do not care what the WOB of his BOV is". The clear statement was that it is only one part of the risk analysis used. I dive a JJ, and cannot use the ALBOV as-is, so what can I do? If it's the choice between not knowing the WOB figures but having a tested and as-manufactured unit, or knowing them for one part (the ALBOV) but hacking away at the rest and doing who knows what to the flow, then it's a no-brainer (tbh I can't believe that a manufacturer that came into existence primarily because other providers were "a man in a shed" and therefore unsafe would actually advise me to take my functioning ccr and modify it in my shed).

You ask why users do not demand figures from their manufacturers, I would counter that the users are not in a position to demand anything. The only way to really make anyone pay attention in the retail market is by not buying their products. If OSEL sold a L-R BOV with published WOB figures then market forces would soon see other manufacturers publishing data to compete before they lost all their market share. At the moment that pressure does not exist. Similarly, as a manufacturer, you can't expect the customer base to come to you ("get another 999+ divers interested and submit a proposal") for something that is unproven. As for the sufficient market, well that is clearly an economic decision that has to be made by OSEL, but as you say, there certainly exists the market for BOVs, and a significant percentage (majority?) of those CCRs have a L-R flow. If no-one with a L-R unit can use an ALBOV, then I can't see how you can conclude that there is no demand for them.

-Mark

 

[Mark Chase]

Brad let me run you through it:

Baught a tec4 BOV very good unit no issues with WOB excelent on OC but wouldnt allow neg tests and a bit of a lump so I sold it

Had a Paragon BOV awfull WOB awfull as an OC reg so I sold it

Baugt a Golum Geer MK1 BOV excelent OC but awfull CCR wob so paid for the upgrade kit which made it bearable but still poor WOB (I could feel it)

So I baught a JJ BOV Fantastic WOB (I was told in testing it was 100% better then the Golum MK1) but wet on OC and por WOB OC

so I baught a Golum Gear Shrimp. This is perfictly acceptable on WOB CCR and on OC so now I own two one on my JJ and one on my KISS


Looked at the APOC and did a try dive. Excelent WOB as a CCR unit not noticibly better than the JJ but still at least as good. Excelent as an OC reg but I only dived it shallow but it was good so I tried to buy one and couldnt because its feeds the wrong way for my unit

Most of the divers I know with Shrimps had the old MK1 Golums and they paid big money to upgrade and i am sure they would upgrade again if something markedly better came along

ATB

Mark

 

[Simon Mitchell]

Sorry I fail to see the differential risk regarding training or lack of, between new and secondhand units.

An individual diver selling a single second hand unit to another untrained diver who may or may not go on to get trained is a very different ethical and moral situation to a manufacturer who is systematically selling all brand new units to the wider population of divers with no requirement for training.

OSEL supply certified functionally safe rebreathers and are the only manufacturer to do so.

I thought to meet your definition of "functionally safe" a rebreather had to prevent you from breathing an inappropriate gas - hence all the features of the currently non-existent (that is, currently not "supplied") iCCR?? Remember - autobailout, end tidal CO2 monitoring etc etc. I fail to see how the O2 Apoc meets this definition of "functionally safe".

Why folk are not asking manufacturers why they are not providing equivalent performance BOVs is an oddity to me.

and

OSEL are not a training agency nor subject matter experts in the training of divers on rebreathers. They simply provide the highest performance kit available; ensure that any user is well informed of the risks they are taking.

I find it "an oddity" that you moralise about rebreather manufacturing companies who don't fully report on the WOB of their BOV, when you sell rebreathers with no requirement for training.

35L/min is lower that the rate for scrubber duration tests agreed in every standard I aware of for overall mixed work/rest dives.

The higher numbers derive their relevance from being plausible maxima that could apply in rare situations - no one is denying that. My point, on the other hand, was that I was exercising at a level that is likely the highest that can be sustained underwater, and that the vast majority of diving situations will not therefore involve the higher minute ventilation figures.

When do you move your experimental protocol into a wet bell like they use in the serious diving trials that utilise exercise bikes?

When there is a need to in order to answer the question we are asking. You asked similar questions when we performed the study to prove wrong your leader's claims about end tidal measurement at the end of an exhale hose, yet the world's leading diving medicine journal had the work peer reviewed and published it as a perfectly valid demonstration of the debated principle - no "wet bell" involved.

And why are you reinventing the workrate for testing a rebreather using an exercise bike? I thought those protocols were quite well nailed down by the experts based on empirical evidence and a lot of in-water trial work.

Because the work rate we have chosen is the correct one for addressing the proposed hypothesis. This is a study investigating CO2 canister storage, temp stick performance, CO2 breakthrough. It is not a WOB test.

To get the best out of an EAC from micropore, you have to design the rebreather around the EAC (as OSEL and Divex http://www.divexglobal.com/capabilities/commercial-diving/helmets-masks-and-scuba/show/cobra have done) and not try and jam an EAC into the rebreather (as APD, ISC, VR and KISS did).

The other rebreather manufacturers you mention (or at least two of them) did test these devices and anecdotally found them inferior (I have seen no data). I am prepared to accept the argument that their unpublished, non-peer reviewed testing may not have been perfect. However, What is self apparent is that the USN tested these canisters and appear to have declined to adopt them or "design a rebreather around them" even though their modular nature would be a significant advantage in the military setting. In the absence of further information I am left to draw my own conclusions.

Sometimes hard to discuss things when your phishing and I am under NDA.

Brad, I don't need to "phish" because I know the situation. I have my own NDA issues so can only discuss what is self apparent to any real world observer: the iCCR is nowhere to be seen despite being months away from shipping 7 years ago (before you were told there was a flaw in the end tidal CO2 monitoring methodology); the "commie unit" was designed and prototypes built, but no one appears to be producing it; the military units do not appear to have been purchased by any military.

AFAIK those customers that bought and paid for production specification eCCRs from DL were and continue to be happy with the rebreathers they received.

Yes, the old word-play line (I note the term "production specification" as opposed to "production") about prototypes supplied to those who commissioned them.

The reasons for why they may or may not be in more general use is I understand it still being debated in court between at least one customer of DL and another party.

Getting closer to the truth here.

Simon, your now a subject matter expert in rebreather training?

You don't need to be a subject matter expert in rebreather training to know that training enhances safety (which is what OSEL is supposed to be about isn't it... Open Safety etc...). Since you have raised the matter of my subject matter expertise, I would be curious to see your boss's publication record in the field of safety systems and safety in complex systems (and I don't mean your own pdfs). I can't find anything using the scientific literature search engines I have available.

OSEL is not a training agency. OSEL mitigates the risk of supply of rebreathers direct to customers through supply of certified functionally safe rebreathers and notification of the risk to customers. Trainers provide training. A different protocol to what others use but when you take the real world actions of divers into account, not a demonstrateably unsafe one.

Good luck trying to sell that rationalisation Brad.

Simon, So why is OSEL the only party who has addressed this problem for recreational users? Why are you not demanding better from manufacturers? Why not start start with APD and have them provide you privately (thus no commercial risk to them) with the WOB of the BOV you dive. Why not point out the suggested recommended level that the WOB should be and have them provide you with a BOV that enables your rebreather to meet this.

There is an excellent post (Steady 1570) above which addresses this issue Brad, and it is a more eloquent articulation of my previous advice that you "shut up about other manufacturers and get on with producing your own unit" than I was capable of. My opinions on BOVs and work of breathing in rebreathers etc are widely published and available to all manufacturers. What they do with that information is effectively up to them. Unlike you, I enjoy an excellent relationship with virtually all rebreather manufacturers (except your outfit) and this facilitates collegial dialogue on such matters, and change may evolve from this. As was pointed out in Steady's earlier post, the thing that will drive such change fastest is if a particular unit has a distinct sales advantage because of specific characteristics. Mark is trying to tell you the same thing.

Simon M

 

[Brad_Horn]

The clear statement was that it is only one part of the risk analysis used. I dive a JJ, and cannot use the ALBOV as-is, so what can I do? If it's the choice between not knowing the WOB figures but having a tested and as-manufactured unit, or knowing them for one part (the ALBOV) but hacking away at the rest and doing who knows what to the flow, then it's a no-brainer.

How can you use something, you do not know, in any risk analysis?

If Low WOB of your BOV is a criteria you can demand this information off the manufacturers who make L-R BOVs. Oh I agree, they will tell you to piss off because a) they have not tested their BOV in the first place or b) they have tested it and want to conceal how bad it really is. Enough folk start questioning their failure to supply and I am sure you will be noted.
You can buy an Apoc and run it mCCR, or buy an rEvo, fit an ALVBOV and run it however you like. But in both cases you either have as low a WOB as has been identified is possible for a rebreather or as near low as in the rEvos case; with the lowest bail-out OC WOB in both cases.

You say "doing who knows what to the flow" but you do not know what the flow is doing anyway (as far as what you are breathing at the mouth verses what is displayed on your gauges); so what changes?
and this is not me recommending that folk change the loop flow of their unit: it is me pointing out that they do not have sufficient information in the first place to make a valid decision, either way. For all we know changing the loop flow of a particular unidentifiable unit could actually be safer for the user.

You ask why users do not demand figures from their manufacturers, I would counter that the users are not in a position to demand anything. The only way to really make anyone pay attention in the retail market is by not buying their products. If OSEL sold a L-R BOV with published WOB figures then market forces would soon see other manufacturers publishing data to compete before they lost all their market share. At the moment that pressure does not exist.

Most BOV WOB in both CC and OC mode, is a factor of a multiple of the ALVBOVs, bar the Hollis and likely Poseidon BOVs in OC mode which is comparable. and for both of them you do not know how high the CC mode WOB is.

OSEL supplying a L-R flow BOV would not see other manufacturers publishing testing; why tell your customers how bad your BOV is in comparison? Just outspend OSEL on marketing showing "experts" who do not know its WOB, using your BOV and recommending it to others. See DLs tongue in cheek piss take on this exact issue http://www.deeplife.co.uk/or_files/Rebreather_Marketing_vs_Engineering.pdf

Similarly, as a manufacturer, you can't expect the customer base to come to you ("get another 999+ divers interested and submit a proposal") for something that is unproven.

How proven do you want it?

If no-one with a L-R unit can use an ALBOV, then I can't see how you can conclude that there is no demand for them.

Mark, it is not that there is no demand for a BOV. It is that customers are not conducting sufficient risk analysis to determine that WOB is a significant contributory factor to their diving. If "experts" like Simon do not bother recommending it occur because they do not know the WOB of their own kit, what hope does the average diver have?

Brad let me run you through it

Mark, I know you did not know the WOB of the BOVs that you bought. Open Circuit divers have been able to know the WOB of their regulators since 1996. So why are you accepting the status quo of buying untested kit for your rebreather?

I fail to see how the O2 Apoc meets this definition of "functionally safe".

Simon, probably an attribute of you failing to understand EN61508.

I find it "an oddity" that you moralise about rebreather manufacturing companies who don't fully report on the WOB of their BOV, when you sell rebreathers with no requirement for training.

Who other than Simon, says there is no requirement for training?

The higher numbers derive their relevance from being plausible maxima that could apply in rare situations - no one is denying that. My point, on the other hand, was that I was exercising at a level that is likely the highest that can be sustained underwater, and that the vast majority of diving situations will not therefore involve the higher minute ventilation figures.

Excellent Simon, I then look forward to the figures you are using being incorporated in the applicable USN and CE standards. When is this occurring?

When there is a need to in order to answer the question we are asking. You asked similar questions when we performed the study about end tidal measurement at the end of an exhale hose, yet the world's leading diving medicine journal had the work peer reviewed and published it as a perfectly valid demonstration of the debated principle - no "wet bell" involved.

No worries Simon. But why bother publishing studies demonstrating already known information?

Because the work rate we have chosen is the correct one for addressing the proposed hypothesis. This is a study investigating CO2 canister storage, temp stick performance, CO2 breakthrough.

So Simon why an earth not use 40L/min, which is the default scrubber duration test flow rate and means the data is benchmark able with every other bit of scrubber test information?
Let me guess you are not using constant 1.3L/min CO2 (USN) or 1.6L/min CO2 (CE) injection flow rates either?

The other rebreather manufacturers you mention (or at least two of them) did test these devices and anecdotally found them inferior (I have seen no data). I am prepared to accept the argument that their unpublished, non-peer reviewed testing may not have been perfect. However, What is self apparent is that the USN tested these canisters and appear to have declined to adopt them or "design a rebreather around them" even though their modular nature would be a significant advantage in the military setting. In the absence of further information I am left to draw my own conclusions.

As you are deliberately blinkering yourself, in the face of evidence to the contrary, that is to your detriment then Simon.
There are direct parallels to your career field as well where the same technology has been found to be as equally high performing as in rebreathers. http://spiralith.com/micropore-inc/

Brad, I don't need to "phish" because I know the situation. I have my own NDA issues so can only discuss what is self apparent to any real world observer: the iCCR is nowhere to be seen despite being months away from shipping 7 years ago (before you were told there was a flaw in the end tidal CO2 monitoring methodology); the "commie unit" was designed and prototypes built, but no one appears to be producing it; the military units do not appear to have been purchased by any military.

Simon, Your problem is you do not "know the situation"! and because of this about all you can do is twist the little information you have. Iain/HSM knows more and he has nothing to do with it at all - think about that!
Just ask yourself which manufacturer is (and has always been) solely capable of producing the "commie unit" based on their ownership of the IP, code and tooling; then read who wrote your NDA?

Simon, Again, what "flaw in end tidal CO2 methodology"?

You don't need to be a subject matter expert in rebreather training to know that training enhances safety (which is what OSEL is supposed to be about isn't it... Open Safety etc...). Since you have raised the matter of my subject matter expertise, I would be curious to see Alex Deas publication record in the field of safety systems and safety in complex systems (and I don't mean your own pdfs). I can't find anything using the scientific literature search engines I have available.

Simon, Does that training enhance safety sufficiently enough to prevent currently occurring fatalities or near-misses? http://www.deeplife.co.uk/or_files/RB_Fatal_Accident_Database_100725.xls

Guess your just looking in the wrong place, try http://www.61508.org/cass/wp-content/uploads/2013/11/CASS30-Rev-0C_CASS-Scheme-Certificates.pdf
Conference presentation to experts on safety in complex systems https://www.youtube.com/watch?v=zL9vVs5vHuQ
Patents for safety related systems http://patents.justia.com/inventor/alexander-roger-deas
However, I guess Alex has just not bothered writing academic scientific literature.

My opinions on BOVs and work of breathing in rebreathers etc are widely published and available to all manufacturers. What they do with that information is effectively up to them. Unlike you, I enjoy an excellent relationship with virtually all rebreather manufacturers (except your outfit) and this facilitates collegial dialogue on such matters, and change may evolve from this.

Simon, yet you do not know the WOB of your own BOV? I guess it is not such an excellent relationship after all if they are deliberately keeping you in the dark on something you know is a critical safety point.

As was pointed out in Steady's earlier post, the thing that will drive such change fastest is if a particular unit has a distinct sales advantage because of specific characteristics. Mark is trying to tell you the same thing.

Simon, I, Alex and the rest of OSEL are fully aware that if OSEL simply had produced a me2 L-R CE marked eCCR unit - as competitively priced as the Apoc is - that did what folk think they wanted, it would sell like hotcakes. See the safety related points earlier though as there is zero chance of any such unit being CE certified to EN61508 at any SIL, let alone the SIL3 that DL have achieved for all their units. OSEL is not supplying a L-R ALVBOV as the default because of safety reasons related to the entire rebreather system across the commie-mil-recreational divide, the flow direction function of the BOV is but a subset of this.

Note that no one has yet identified why they really need a L-R flow BOV and why this is any different at the mouth for the gas they are breathing, to having a R-L flow one. Noting the only thing in every rebreather stopping the flow is the flapper valves within the BOV itself.

The Apoc inherently has those distinct sales advantages based on the very high and documented breathing performance in all regards of the rebreather but the focus is on user safety, which is at odds with other options available from others.
From a pure marketing and sales POV, it is also not available off the shelf as an eCCR (yet); however, that does not negate the key elects of the loop that are of interest to you from an academic safety viewpoint. That you are blinkering yourself to these based on your relationship to other manufacturers is not something I can assist you with. They are there, they exist and for those that honestly want them, they are available.

For those running R-L loops the ALVBOV is a drop in best in class (by a significant margin) solution that at worst just needs an adapter be made to fit the CL end fittings or in the case of the shockingly narrow bore ones on the rEvo, replace them. The ALVBOV has set the standard for the WOB that users should be expecting from their BOVs in both OC and CC modes.

 

[Dave1w]

For those running R-L loops the ALVBOV is a drop in best in class (by a significant margin) solution that at worst just needs an adapter be made to fit the CL end fittings or in the case of the shockingly narrow bore ones on the rEvo, replace them. The ALVBOV has set the standard for the WOB that users should be expecting from their BOVs in both OC and CC modes.

You have mentioned this a couple of times, what are you referring to in the rEvo, that is particularly narrower than other units?

Another question I have, what is the effect in running the APOC loop backwards
(assuming it were some way possible to reverse the BOV)?


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[Brad_Horn]

You have mentioned this a couple of times, what are you referring to in the rEvo, that is particularly narrower than other units?

Dave, it appears that the OD of the rEvo CL fitting is 34mm, in direct comparison the same CL end P-port fitting supplied with the ALVBOV which has an OD of 48mm.
As you know the ALVBOV 90' fitting is also ported using injection moulding for maximum flow, thus giving you a straight minimum length breathing hose from CL fitting to BOV for minimal WOB and buoyancy etc whereas the rEvo is just a straight upwards pointed fitting that requires the narrow bore hoses to be either excessively long or kink to get to the BOV.

Another question I have, what is the effect in running the APOC loop backwards
(assuming it were some way possible to reverse the BOV)?

Dave, off the top of my head:
- IIRC a 0.02 difference in PPO2 measured at the mouth, compared to the POD being on the inhale side. Your going from one extreme to the other for location.
- water would drain back into the exhale CL rather than flow through to the inhale CL; but as both CLs have water dumps, this is minor: though critical if using kitty litter - against recommendations - in it.
- less of a CL water trap on the new exhale side pre-scrubber so you might have to be more aware of any water in the loop and listen for the audible gurgling.
- potential that during rapid ascent the OPV would suck out any newly added O2 prior to the diver breathing it. You could fit OPV to "new" inhale CL and block off existing OPV.
- probable near doubling of the complete loop WOB depending on the specific L-R flow BOV fitted as reversing the flow direction is impossible with an ALVBOV.
- wrong colour coding on the loop red v green etc
cannot think of much else. As to get the most out of the EAC it has flow cones at each end that are interchangeable in order to have the required linear flow for optimum scrubber efficiency and the rest of the unit is pretty much interchangeable when you mirror sides. ALV is in your mouth for safety. o2 injection is still in the scrubber though now post rather than pre.

 

[Dave1w]

Looking at the rEvo in relation to a lot of other rebreathers, I don 't think it is excessively narrow, Perhaps just compared to the Apoc with the large p-ports. I didn't take the opportunity to measure the ID, but significantly better than the previous P-port - an indicator for me is that the nut on the inside has gone from the p-port nut to the larger nut used on the dolphin breathing hose (I think), the Ray hoses have a bit of stretch and I would imagine is with the new connectors, as well the removal of rather restrictive drager elbow is a big improvement. Optimised or not, a 90 degree change of direction will have an effect.

The hoses are pretty much industry standard size, don't kink too easily, and compare well to other high class offerings such as The MK15 thingies, and VRs which seems to do OK, so possibly it is unfair to single them out. I have tried using shorter hoses on units like the KISS, resulting in pretty restricted head movement, which to be fair the Apoc does suffer from with the short stiff hoses, and the tubes.

My point on reversing the loop is that most units would have similar issues, making them less than optimal than designed, whether it is water traps, oxygen injection point, or final PO2 readout, which, as you have pointed out, is still retained in the standard. I was having a look at the Albov and really it is the design choice of putting the exhale flapper on the BoV and the inhale on the hose tube ( understandable and good design for obvious reasons). I did not look close enough to see if the exhale spider/carrier can be removed, or if it is fully integral part of the moulding, which while cheaper to make could raise issues down the line. I rather fancy, someone who knows what they are doing could convert it to L-R, and not lose too much performance in the meantime. I'd want to know what the replacement cost of the body is though before having a go.

Cheers
Dave


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[WFO]

So just to put the cat among the pidgeons why don't OSEL release data on rest of market offerings WOB? Presume they have the toys both to test and to do testing with.

 

[Mr fish]

more fun / harm done by slagging others off and posting there own bov numbers,

they don't give two fook,s about users , is just c6nts doing what they do best , ie being c6nts ,

 

[WFO]

more fun / harm done by slagging others off and posting there own bov numbers,

they don't give two fook,s about users , is just c6nts doing what they do best , ie being c6nts ,

Oh yeah mr deas has never been shy about slagging AP off.

And I'm sure he has in fact tested the competitions offerings.

So why would he not post them? Must be that they're actually better than his lol

 

[steady1570]

How can you use something, you do not know, in any risk analysis?

What you are referring to is the degree of granularity that one applies to risk analysis. In the simplest, digital measure, you can have breathe or not breathe. At the other end of the spectrum is 0.001 J/L differential. Each has merit and can be used in a risk analysis with varying utility, as can more subjective measurements in between. Ultimately these measures have to be added to the other risks before a decision to dive or not can be made. Focusing too much on numbers and theory can obscure the picture that you are trying to obtain.

If Low WOB of your BOV is a criteria you can demand this information off the manufacturers who make L-R BOVs. Oh I agree, they will tell you to piss off because a) they have not tested their BOV in the first place or b) they have tested it and want to conceal how bad it really is. Enough folk start questioning their failure to supply and I am sure you will be noted.

As I said previously, a consumer can only “demand” with his wallet. If there are no alternatives with documented WOB, then I simply cannot force a change through my spending power by choosing those BOVs over less documented ones. I could buy a new unit as perhaps the ultimate sanction, but I want to spend hundreds not thousands and my personal risk tolerance is ok with that. Again, if OSEL doesn’t want to compete, then that is a commercial decision, but if they/you are so confident that the ALBOV system is so superior, then I wouldn’t have thought any advertising budget that the competition might deploy would matter, results would speak for themselves

You say "doing who knows what to the flow" but you do not know what the flow is doing anyway (as far as what you are breathing at the mouth verses what is displayed on your gauges); so what changes?
and this is not me recommending that folk change the loop flow of their unit: it is me pointing out that they do not have sufficient information in the first place to make a valid decision, either way. For all we know changing the loop flow of a particular unidentifiable unit could actually be safer for the user.

That is patently false. Whilst they might not have the published WOB figures of the APOC / ALBOV, these units (e.g. JJ) are CE compliant and have undergone testing in that process. As you point out in your answer to Dave1w, changing one thing has unintended consequences elsewhere. I am not convinced that even you really believe that an amateur changing the flow of a rebreather loop will lead to a safer unit.

How proven do you want it?

It’s completely unproven - as you yourself say, OSEL do not make a L-R BOV so it has never been tested.

Mark, it is not that there is no demand for a BOV. It is that customers are not conducting sufficient risk analysis to determine that WOB is a significant contributory factor to their diving. If "experts" like Simon do not bother recommending it occur because they do not know the WOB of their own kit, what hope does the average diver have?

Your argument could be correct, but I would offer an alternative and perhaps more plausible interpretation that divers actually are conducting sufficient risk analysis, and are coming to the conclusion that they need a BOV to improve their safety. They only have the qualitative (breathe easy, hard, not at all) measures, but still determine that this is a less risky proposition that either not having one or trying to force an incompatible BOV onto their unit.

I think that Simon has made his areas of expertise very clear, and to say he does not “bother” does a disservice to any serious discussion in this thread.

-Mark

 

[Simon Mitchell]

Simon, probably an attribute of you failing to understand EN61508.

I was only repeating what you and Alex have said about the reasons for the iCCR many times in the past. If you can meet the EN61508 definition of functional safety in a rebreather by selling a bare O2 loop to untrained divers then fine.

Who other than Simon, says there is no requirement for training?

Obviously I have never said there is no requirement for training. Quite the opposite in fact. On the other hand, you have admitted that you do not require a diver to be trained or undergoing training prior to selling them a complex life support device.

Excellent Simon, I then look forward to the figures you are using being incorporated in the applicable USN and CE standards. When is this occurring?

Read and attempt to comprehend the post Brad. I was not suggesting the standards need replacing; merely that the circumstances they apply to are unlikely to occur very often in real world diving.

No worries Simon. But why bother publishing studies demonstrating already known information?

I'm surprised you are keen to have this conversation Brad, because there is a clear trail of internet posting that prove Alex did not "know" or understand the issues even on having it pointed out to him. For example, if one goes to:

http://www.rebreatherworld.com/dive...sion-co2-monitoring-split-another-apoc-1.html

It is possible piece together the following:

The DL explanation of how end tidal CO2 monitoring in the Apoc worked at the time: The end of exhale is the peak CO2 reading. The OR rebreathers measure end of exhale gas by measuring the peak exhaled gas, using dual channel IR, at the end of a (very short) exhale hose.

The concerns about this that I articulated: The gas passing through the exhale tubing is a mixture of end-tidal gas and dead space gas that was in the airways (such as the trachea and bronchi) but did not participate in gas exchange and which therefore does not contain CO2. The net effect is that the end tidal CO2 will be diluted and the PCO2 measured at the sensor on the shoulder will not be an accurate indicator of arterial PCO2 (it will be low).

Alex's response to my concerns: The temporal spreading of that (dead space) gas in a short rebreather hose is well under 0.5s, so does not have any significant effect on the peak CO2 .... and ..... The problem you are concerned about does not exist.

So we performed and published a study to prove what Alex did not appear to know, which concluded: "Measurement of the peak exhaled PCO2 at the end of a rebreather exhale hose may significantly underestimate the true end-tidal CO2 at low tidal volumes". Ineson et al. DHM 2010;40(4):206-9.

So Simon why an earth not use 40L/min, which is the default scrubber duration test flow rate and means the data is benchmark able with every other bit of scrubber test information?

Benchmarking of this nature is neither necessary nor even desirable in the experiment we are performing.

Let me guess you are not using constant 1.3L/min CO2 (USN) or 1.6L/min CO2 (CE) injection flow rates either?

You're right, we're not. We are using the CO2 production measured in our human subjects exercising at 6 Mets because that is the level of exercise that expert consensus has agreed is likely sustainable during diving.

As you are deliberately blinkering yourself, in the face of evidence to the contrary, that is to your detriment then Simon.
There are direct parallels to your career field as well where the same technology has been found to be as equally high performing as in rebreathers. http://spiralith.com/micropore-inc/

I could not find any comparisons with diving grade sofnolime at your link.

Simon, Your problem is you do not "know the situation"! and because of this about all you can do is twist the little information you have. Iain/HSM knows more and he has nothing to do with it at all - think about that!

I have no idea of the relevance of your reference to Iain, and with all due respect, how would you know what I know or don't know?

Simon, Again, what "flaw in end tidal CO2 methodology"?

The flaw was the original plan to measure end tidal CO2 directly at the end of the exhale hose, which history faithfully records you changed several years later after the problem with it was pointed out to you (see above). Actually, let me remind you....

Remember this quote from Alex above?.... The temporal spreading of that (dead space) gas in a short rebreather hose is well under 0.5s, so does not have any significant effect on the peak CO2

Well, after that exchange Alex disappeared for about 18 months (and the iCCR that was supposedly only months from release didn't appear), and he then re-emerged and described a new method of measuring end tidal CO2. The description appeared in the DL "Fault Study Report" which had this to say:

"The Deep Life CO2 monitor in the OR rebreather is unique because it measures volume weighted average exhaled CO2 and then applies a correction for the effect of the dead space..."

I guess that will be the "dead space" that he originally thought "didn't have any significant effect on the peak CO2".

The scariest thing about all this is not that he got it wrong initially, but rather the hubris that has prevented admission of an honest mistake ever since.

Simon, Does that training enhance safety sufficiently enough to prevent currently occurring fatalities or near-misses? http://www.deeplife.co.uk/or_files/RB_Fatal_Accident_Database_100725.xls

I seriously doubt you will convince anyone that proper training does not enhance safety Brad.

However, I guess Alex has just not bothered writing academic scientific literature.

No, he has not.

Simon, yet you do not know the WOB of your own BOV? I guess it is not such an excellent relationship after all if they are deliberately keeping you in the dark on something you know is a critical safety point.

Nobody is deliberately keeping anyone in the dark. The manufacturers have met the standards required of them. Under these circumstances the logic of decision making around BOVs and WOB etc has been explained to you by myself and others (see below).

From a pure marketing and sales POV, it is also not available off the shelf as an eCCR (yet); however, that does not negate the key elects of the loop that are of interest to you from an academic safety viewpoint. That you are blinkering yourself to these based on your relationship to other manufacturers is not something I can assist you with.

No, I agree that it does not negate my interest. However, you seem incapable of accepting that divers (including me) are not flocking to buy your O2 rebreather just because it has the lowest work of breathing. The reason for this is nothing to do with relationships with other manufacturers but rather that those manufacturers currently offer packages that when viewed holistically have more to offer than an oxygen rebreather with low work of breathing. Produce your iCCR, and if it works well, this situation may change.

Simon M

 

[Brad_Horn]

So just to put the cat among the pidgeons why don't OSEL release data on rest of market offerings WOB? Presume they have the toys both to test and to do testing with.

DL did this years ago, which is sole reason why you can know the WOB of the APD DSV or JJ-BOV or Boris DSV etc etc in comparison http://www.deeplife.co.uk/or_files/FMECA_OR_V4_140831.pdf
They needed to do that comparison of other products on the market in order to determine ALARP and to achieve CE.

For the alternative view, see Simons comment about the logic of decision making by customers, being better if the do not know the WOB of what they are buying.

Focusing too much on numbers and theory can obscure the picture that you are trying to obtain.

Not if that is the sole non-subjective grading mechanism that you have.
As Simon has cited, low WOB has quite a solid recommendation for its consideration. You can only achieve that by knowing the actual WOB in the first place.

As I said previously, a consumer can only ***8220;demand***8221; with his wallet.

As Simon has advised, not all consumers are equal in their relationship, with the manufacturers. Some "customers" simply refusing to represent the product on behalf of the all consumers could be sufficient to acquire the knowledge. However, as Simon points out above, that will not happen because others have decided what you should and should not know about your kits WOB! An oxymoron for a safety advocate - who cites that low WOB is good - if ever I have heard one. BUT thats the line that Simon has to take to maintain his relationships, so no quibbles, I just find it at odds.

Again, if OSEL doesn***8217;t want to compete, then that is a commercial decision, but if they/you are so confident that the ALBOV system is so superior, then I wouldn***8217;t have thought any advertising budget that the competition might deploy would matter, results would speak for themselves.

OSEL is competing but within the criteria needed for their products to be CE certified. An R-L loop was a part of that process.

That is patently false. Whilst they might not have the published WOB figures of the APOC / ALBOV, these units (e.g. JJ) are CE compliant and have undergone testing in that process. As you point out in your answer to Dave1w, changing one thing has unintended consequences elsewhere. I am not convinced that even you really believe that an amateur changing the flow of a rebreather loop will lead to a safer unit.

No it is not, because again you do not KNOW the results of the flow of the loop.
AFAIK JJ did one audited test for CE certification - which I could be wrong but is unlikely to be sufficient to advise anyone that they know the affect of the loops flow.

As I listed to Dave1w above. Changing the direction of the loop flow on the units I dive will have an effect, but it is known. Because the design is known therefore changing the flow direction has known intended consequences elsewhere.

What I do know is that: I do not know if an amateur changing the loop direction of the CCR that you dive will be more or less unsafe. Because the current state is unknown!
Take Simon for example. If he buys an ALVBOV and fits it to his FMCL unit as this chap did https://www.facebook.com/1512989548...1298954899613/958370847525749/?type=3&theater he has just significantly decreased his overall WOB: by a near factor of 4 for that one component. Safer (in isolation) = Yes. BUT then there are a whole host of pre-existing unknowns that I do not know the consequences of the change (good/bad) because they are unknowns to begin with. So as an end sum, the only thing I know is Simon will have reduced a components WOB and therefore his total loops WOB by a significant margin, and that he now knows his BOVs WOB when he bails out onto it.

It***8217;s completely unproven - as you yourself say, OSEL do not make a L-R BOV so it has never been tested.

What are you expecting to change with a mirroring of the required parts?

I would offer an alternative and perhaps more plausible interpretation that divers actually are conducting sufficient risk analysis, and are coming to the conclusion that they need a BOV to improve their safety. They only have the qualitative (breathe easy, hard, not at all) measures, but still determine that this is a less risky proposition that either not having one or trying to force an incompatible BOV onto their unit.

Mark, I am in complete agreement with you but also state that that need not be the case. Remembering that when they NEED their BOV in anger that qualitative scale will be at the extreme end of workload: so unevaluated by the diver.

require a diver to be trained or undergoing training prior to selling them a complex life support device.

Simon, Please advise:
1) How many rebreather manufacturers admit to selling a "complex life support device";
2) Which rebreather manufacturers only sell a diver a rebreather AFTER training has been conducted on the unit?

I was not suggesting the standards need replacing; merely that the circumstances they apply to are unlikely to occur very often in real world diving.

and Simon, the reason that the criteria exist in the standards is that they occur in real world diving. What does Guessing the middle of the envelope or bell curve prove?
Take recent Finnish example 4'C water, 100+m, CO2 rate and workload was how much?
or Dave Shaw and the list goes on.

there is a clear trail of internet posting that prove Alex did not "know" or understand the issues even on having it pointed out to him.

Only Simon, if one relies on internet posts and one fails to consider evidence to the contrary.

So we performed and published a study to prove what Alex did not appear to know, which concluded: "Measurement of the peak exhaled PCO2 at the end of a rebreather exhale hose may significantly underestimate the true end-tidal CO2 at low tidal volumes". Ineson et al. DHM 2010;40(4):206-9.

and Simon I believe as you are well aware, the critical point you gloss over is that you failed to be definitive either way. IIRC at the time Alex pointed out to you that with the heath robinson affair you used for a loop, DL with an entire engineering team behind them, would have failed to measure end-tidal CO2 at the end of the loop either, certainly no may about it.
Whilst at the same time DL were using the iCCR Monitor to verify a Mass Specs readings of CO2 at 100m and identified an unchallenged flaw with in-service DSV and BOV flapper valves. http://www.deeplife.co.uk/or_files/Fault_Study_CO2_Bypass_110314.pdf

We are using the CO2 production measured in our human subjects exercising at 6 Mets because that is the level of exercise that expert consensus has agreed is likely sustainable during diving.

Simon, Could you please cite the references for this.

and with all due respect, how would you know what I know or don't know?

Because with all due respect, I know what you are quoting (on this specific topic before too many fans get their knickers in a knot) is crap. I not only know both sides, I know all three sides (in at least some detail for each): whereas you refuse to accept you have only had limited access to one. Even that evidence, you are looking at, with blinkers on.

The flaw was the original plan to measure end tidal CO2 directly at the end of the exhale hose, which history faithfully records you changed several years later after the problem with it was pointed out to you (see above).

Simon, the only slight hiccup I see with this argument you keep trotting out as if it means anything, is that nothing has actually changed with regards how the iCCR measures end-tidal CO2.

I seriously doubt you will convince anyone that proper training does not enhance safety Brad.

Agreed, because I am fully in support of proper training. It would however be even better if that proper training mandated the use of BOVs and retaining straps!

Nobody is deliberately keeping anyone in the dark. The manufacturers have met the standards required of them. Under these circumstances the logic of decision making around BOVs and WOB etc has been explained to you by myself and others.

I get it. So the logic of someone elses decision, tells why your kept in the dark and why you do not know the WOB of your own OCB yet at the same time allowing you to cite the recommended WOB that your UBA should meet; to be safe to dive.

A rebreather meeting CE <> to WOB being under 1.5-2.0J/L during a real dive. Two VERY different things. If the CE standard was changed to 2.0J/L maximum, then as we both know, very few CCRs would pass.

BTW what maximum WOB on Heliox at 100m does the CE standard require of a rebreather? 2.75J/L is it not!

However, you seem incapable of accepting that divers (including me) are not flocking to buy the Apocalypse CCR just because it has the lowest work of breathing. The reason for this is nothing to do with relationships with other manufacturers but rather that those manufacturers currently offer packages that when viewed holistically have more to offer than an mCCR with low work of breathing.

Chuckle. Simon, I have no issue with this line of reasoning, but it has bugger all to do with divers not knowing the WOB of their BOV.
After all this thread is about BOVs and you appear to have failed to address why it is a bad thing consumers of L-R BOVs having access to the WOB of those BOVs. Such that they can know their WOB and chooses appropriately based on your recommended cited WOB, for their improved safety.

 

[steady1570]

This

OSEL is competing but within the criteria needed for their products to be CE certified. An R-L loop was a part of that process.

and this

What are you expecting to change with a mirroring of the required parts?

are contradictory, no? If you do not expect anything to change with a mirroring (which I agree with), then why is it a requirement for CE for it to be R-L? Commercially sensible due to potential customer base fine, but not a safety requirement.