Hollis publish QinetiQ Feb 2019 testing report for the PRISM II FMCL & BMCL attempt at CE

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Brad_Horn

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OSEL would like to take the time to congratulate Hollis on a cracking first attempt to get their PRISM II prototype FMCL and BMCL units through the EN14143 test requirements, to try and get CE marking. While this is old news from Feb 19, the testing done at QinetiQ was a solid effort, and it would be good to see more rebreather manufacturers stepping up to this level and openly publishing their results as you guys have done. https://www.hollisrebreathers.com/wp-content/uploads/2019/08/QQ-1900385-HollisPrism-v1-1.pdf
While it only discloses the results of 15 of the 52 odd testable requirements EN14143 has, this is a lot better than most have published and in more detail.

Obviously with a WOB of 1.9J/L (with BOV) or 1.68J/L (with DSV) at 40m with Air at 75lpm, the PRISM II doesn’t offer the lowest WOB of available mixed-gas CCRs, but it is one of the better options.
Of course the Apocalypse Type IV CCR is still better at 1.44J/L. http://www.deeplife.co.uk/or_files/DV_OR_WOB_Respiratory_C1_101111.pdf

It would be good to also see the OC WOB of the HOLLIS BOV disclosed as required for EN250, even if on the PRISM II fitting one increases the units WOB. And look forward to seeing what form of retainer or gag strap Hollis have incorporated on the DSV/BOV to prevent the diver drowning if they go unconscious, as needed per EN14143.
However OSEL do like that the ALVBOV still offers the lowest WOB in OC (and CC modes) of any BOV at 0.89J/L at 50m on Air at 62.5lpm http://www.deeplife.co.uk/or_files/DV_DL_ALVBOV_Breathing_Params_A3_100318.pdf so its likely that your engineers can squeeze a little more OC safety performance out of your BOV, for when divers really need to use it.

For a professionally designed rebreather, passing the minimal EN14143 hydrostatic requirements with BMCL, is quite achievable. http://www.deeplife.co.uk/or_files/DV_DLOR_HydroImbal_101116.pdf

Personally I’m interested in how you are going to redesign the unit to enable a wing BCD to be safely used at the same time as BMCL. Noting the QinetiQ comments "It was noted that the movement of the rear-mounted counterlungs during ventilation could be restricted by the position of the wing buoyancy compensator (WBC), particularly if inflated. It was also of concern that the function of the exhalation counterlung variable exhaust valve (VEV) could also be compromised.”
As OSEL learnt, achieving a minimum breathable volume of 4.5L in all orientations when dived is a critical safety consideration that wasn’t covered in this QinetiQ test and I look forward to seeing how you solve this for the PRISM II, so the wing can safely be inflated and used during a dive. http://www.deeplife.co.uk/or_files/DV_OR_Tidalvolume_090911.pdf

It was good to see the unit achieving a 95min 40m BT duration for the scrubber endurance, with a profile ascent afterwards. Are you intending to do a constant 40m and 100m test to allow users to directly compare this with other units that have achieved CE?
Of note, something that might save Hollis quite a few $$$ and is something that cost OSEL a couple of years in getting our unit to market, is that EN14143 critically in black and white, requires the CO2 for scrubber duration to be recorded ‘in the mouth’. OSELs original scrubber duration testing was done as you had QinetiQ test for and when our Technical File was reviewed by the Notified Body formally for certification those original results from 253 odd duration runs, were rejected as they didn’t take the dead space of the DSV/BOV into account. We have found that a Micropore EAC at 2.2kg equates to roughly 2.6kg of granular sorb, so you are likely looking at very comparable results to the Apocalypse for actual scrubber duration when the PRISM II is tested ‘in the mouth’. http://www.deeplife.co.uk/or_files/DV_OR_ScrubberEndurance_Retest_SRB_101215.pdf

OSEL are quire happy to sell you a better breathing simulator that will considerably speed up and reduce quite significantly your in-house testing costs to enable your engineers to more readily test & evaluate new prototype PRISM II configurations so you can ensure a future pass for EN14143 testing at QinetiQ. The datasheet for our latest iBreathe MkIV machines can be downloaded from www.opensafety.co.uk/files/Datasheet_iBreatheMkIV_1906.pdf
Like most technology, each generation has brought in more features, become easier to use and faster, at ever lower cost. For comparison, the older iBreather MkIII machines were sold at 86K Euro, and if one goes back to first generation machines like the ANSTI rebreather test machines or our first Mk1 Simulator, these were around 180K Euro for a rebreather test unit, and took weeks to complete a full set of tests. The iBreathe 4th generation brings the costs down to a level where any serious company involved in respiratory systems can have them in-house, and can do the entire set of CE respiratory tests in a morning.

Even though Hollis have obviously had to go back to the drawing board and redesign the PRISM II to reattempt future EN14143 testing, simply having near peer competitors documenting their testing and now starting to offer documented higher performance recreational rebreathers, is good for the industry.
 

michael-fisch

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Oh Brad, why do you always try and dump on all others?
Can't you finally get your sh** together and start delivering the rebreathers that you claim to make?
That way you could also take the criticism that others would have for your design, and maybe learn something from it.
Whining about what others do, without doing something yourself, is like kindergarten.

Michael
 

Cyborg Pirate

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Well I absolutely love my Prism 2.
 
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Brad_Horn

Brad_Horn

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Can't you finally get your sh** together and start delivering the rebreathers that you claim to make?
That way you could also take the criticism that others would have for your design, and maybe learn something from it.
How many rebreathers do you want? Commercial, Military or Recreational end use?

Feel free to start a new thread and list any and all criticism. If its a CE certification requirement not much can be changed. If its purely subjective feedback it is noted for consideration but the design won't suit everyone. If its safety critical OSEL will stop shipping that component, require it be redesigned and re-issue it free of cost to all current customers as well as include it by default in all future shipments. The last point is the hold on the iCCR Monitor and that hold originated due to issues not even on OSEL units.

An excellent case study of OSEL responding to criticism with the design, that cost well over US$100k to fix, was a single customers complained that their Apoc's off the shelf BCD waterdump - that every BCD uses and most rebreathers - wasn't good enough to allow repeatable flood recovery. The customer was right. The waterdump could seat an an angle. It was originally the best that could be offered but reviewing the design enabled an improvement and now all customers using OSEL rebreathers can reliably conduct full loop flood recovery whilst submerged. The upgrade was offered free of cost as it related to users safety.

There is still a bottle of single malt on offer for anyone who discovers a safety critical design issue with the units OSEL ship that is undocumented.

Didn’t know OSEL still existed?
OSEL will be around for the long term.

Don't trust anything from those folks, in their infamous list they include OC accidents as rebreather accidents
You want to mention which specific one! DLs list has over 500 individual incidents listed at the moment.
One presumes you notified DL directly of this extremely significant error on their behalf.... If so, quite happy to chase it up for you if you want to mention when exactly you notified DL and which specific incident you refer to!

DL maintain their dynamic accident list as a CE requirement for the Functional Safety certification of their various units. Deep Life Design Team: databases and analysis of rebreather accident data It is also the ONLY accurate and somewhat up to date global resource for folks interested in rectifying the issues causing rebreather fatalities or just tracking them.

Well I absolutely love my Prism 2.
Which is great.
But because Hollis have also tested it and openly published its results. You know its shortcomings. Which is also important.

One presumes as a safety upgrade, when they get around to offering CE certified BMCL and loop components, they will offer those free of cost to existing users. :wink:
 

Mod63

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You want to mention which specific one! DLs list has over 500 individual incidents listed at the moment.
One presumes you notified DL directly of this extremely significant error on their behalf.... If so, quite happy to chase it up for you if you want to mention when exactly you notified DL and which specific incident you refer to!
I have to do squat. DL has to do due diligence before publishing. It just shows that DL is full of sh.t and is making up accidents.
 
https://www.shearwater.com/products/swift/

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