Rebreather Comparison Chart

Drmike

Personally I dont care so much about the scrubber durations or their effciency (amount of sorb/min duration) as I do for WOB results

All units can achieve longer duration than I can ever do kicking out that much CO2 in one go. If Im puffing that badly for that long WOB and poor ventilation is gonna kill me long before the scrubber wears out I suspect

On big dives (big deco) your most likely only working hard for 30mins - 1 hour
likely any of these scrubbers will be fine*

On very deep (or again very long distance) dives you are most likely using a scooter

So to me the best unit is one that has the best WOB and a reasonable scrubber life (30 mins difference in scrubber duration means nothing in the real world where we best guess when to change based on usage or next dive requirements)


A high WOB will contribute a lot to things accelerating to becoming pair shaped when the sh1t hits the fan.

I recall when I 1st breathed from Boris I spat out the mouthpiece and told Phil Short that it breathed amazingly -nice to have a number now - but just look at the difference between Boris WOB and the rest. 1.6! Jeez.


*Having said that scrubber life at depth is not linear for all units. I know one of those units that is roughly the same duration as boris at 40m lasts only 1/4 as long as boris at 100m!!

But as Phi's poll showed the vast majority of people are diving 30-40m range, so its not such an issue.


Another point is if I want to make the dive safer (from a scrubber expiry viewpoint) I can put in a fresh fill, but I cant do anything to change the WOB.....

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Steve

And Mike gets the Gold Star.

Measuring units in all the ways mentioned here ignore the 'really' important things, WOB, redundancy, flexibility, robustness etc etc

I do care about scrubber life but when units out there have things that should be fixed like common electrics with no real redundancy (inspo and evo), only 2 sensors displayed on each display (rEvo and Palagian), sh1tty battery life (optima), made of fragile materials (PRISM), pressure differential across sensors (Meg), and the bloody thing keeps leaking (Boris) then looking at the things I mentioned in the first and this list should be foremost in ones mind. Well in my eyes anyway

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lizardland

Steve,

you haven't flagged anything up on the KISS. Can you please include a criticism so those with lesser rebreathers don't start whinging again

Cheers,

Stuart

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PhilSiswick

It's affirmative action in operation - you're such a minority that the rest of us have agreed not to pick on you ;-)

Cheers,

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Phil

No comment on open circuit... it's an evolutionary dead end not really worth discussing here. Dave Sutton, 2007

I have always felt that the dive I am on is not nearly important as the dives I plan to be on the rest of my life. Tom Rose, 2007

www.hugsac.org.uk

Nad

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Steve

oops, my mistake erm..... problems with displays leaking.

(Now sitting in the corner )

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WARNING: I contain occasional coarse language, extreme sexual references, nudity, and adult themes, which may offend some people - Usually churchy types.

AD_ward9

A colleague kindly pointed out that none of the units listed meet the EN14143 requirements for WOB except the Sentinel and Boris.

Alex

PhilSiswick

Does that put the validity of the tests in question? Unless I've got my ENs all confused, the Inspo family must have passed EN14143 to get CE approval. So, what is different about these tests that means that they failed and are they still valid if they don't show the Inspos passing?

Cheers,

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Phil

No comment on open circuit... it's an evolutionary dead end not really worth discussing here. Dave Sutton, 2007

I have always felt that the dive I am on is not nearly important as the dives I plan to be on the rest of my life. Tom Rose, 2007

www.hugsac.org.uk

AD_ward9

No, I think Kevin's test results are valid. The Inspo fails CE WOB here also.

The Inspo is one of the units we publish comparative data on. It is just that we have to redo our WOB tests due to a wee change we introduced to the OR breathing loop, so have not got that particular report out yet. Our hydrostatic report is out though, with comparative numbers on Inspo and Draeger. See http://www.deeplife.co.uk/or_files/O...vC5_070810.pdf for example.

I believe the Inspo was CE approved simply because it existed before EN14143:2003, so did not need any testing. Draeger got the Dolphin approved the same way I understand. The Inspo generally does meet EN14143, except it fails the EN61508 requirement abysmally and fails both PPO2 control and WOB requirements in the tests we carried out here. The WOB goes up further, to an extremely high figure when the scrubber is spent: Kevin's WOB figures seem to use a fresh scrubber. We prefer using a spent scrubber, as that is the worst case, as required by the spirit of EN14143. The Boris is the closest to a true CE unit just now, except for the EN61508 compliance, but even there the Boris and Sentinel are lot closer than any of the existing units out there.

Kevin's email is full/blocked, so I will see him at DEMA. Us doing back to back tests of the same configuration makes a lot of sense, as it gives a set of "independent figures" for each of us. Our reports are usually extremely detailed, so anyone can see the exact test, test conditions, results and intrepretation and reproduce or challenge the result. This makes a nice complement to Kevin's quick chart.

I really like Steve's chart of what are the key issues. We will try and do that for DEMA 2008.

On the importance of the WOB I agree completely with Dr Mike on this. Many Rebreather divers do deep dives: this is really clear in the accident reports. After all, most RB divers are a lot more experienced than the average OC diver and a large proportion do deep O.C. before the RB. On these dives, WOB is very important.

Alex

NB: I am not suggesting APV did not test the Inspo. They used DERA a lot, and have an ANSTI machine which I am sure they use. I refer simply to the conclusion we have after doing a lof of tests and working with CE Notifed Bodies. It may be right, it may be wrong, but is our conclusion after making our best efforts to get the facts, and after doing a lot of testing.

Beanie

er the Evo and inspo vision are both post 2003

so?

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