Brad_Horn
Contributor
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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.
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.
