ISC posts test data

Hanssing

Hi Alex,

As allways it is a pleasure to read your informed posts.
I have several times wondered about what you write below, wich is completely in line with what you have written before regarding WOB and scrubber-usage:

One of the keypoins we keep returning to is comparable test-results based on comparable test-conditions! I therefor have a hard time understanding if it is your oppinion or the ENxxxx specifications that dictates the WOB-messuremeants with used lime?

The reason is, I see "near exhausted lime" as hard to define and reproduce for a testing-house.
In essence you only have one go to perform the meassurement - right a breakthrough. IMO, it would make more sense that the standard used an clearly defined scubber-state wich is offcourse unspent, and then set the pass-levels so they would encompass the expected deterioration in WOB through scrubber-life.

From a safety-perspective i completely agree with the notion that things should be tested in worst-case scenarious, but from a meassuring perspective this gives a "wobbly" foundation for the WOB-figures....
Even the packaging density is probably hard enough to get comparable for user-packed scrubbers, that comparing result makes sense at all. But ofcourse the packaging should be the same for all tests, wob and duration etc....

BTW: It is clear that testing with fresh lime would rob the EAC-designs (like the OR) of one of its advantages; that the deterioration with use is much less that granular.

So my questions boils down to:

1. Does the standards really say "near exhausted lime"?
2. If they do, how is this lime-state defined?
3. Does the standard specify wether WOB is meassured with the scrubber active or not, ie. with co2-production, scrubber at temperature and correct working moisture-levels.?

Regards
Nicolai Hanssing

__________________
Woohooo - I can change my rEvo!
Its going to be bitchin' tricked out piece of gear

AD_ward9

The standards require testing in the worst case normal operating conditions. They do not define the details in every case.

The standards have WOB tests separate from scrubber life tests. They are not specific enough in this area. This means that people can bypass the intent, which is to test under worst case normal operating conditions, but using fresh lime. The WOB tests do not involve CO2 generation, but are at 4C (this makes no difference to WOB in my experience).

Alex

AD_ward9

Here is the data I promised to post.

ISC published mouthpiece figures, but the conditions were not too clear. I understand Golem Gear and others have an interest in this detail, so here are our independent mouthpiece figures for Meg, Inspo original, Dolphin and DL mouthpieces. The Ouroboris should be very similar to the DL figure (neck and neck on that component, as the geometry is almost the same and both use very floppy mushrooms). Sorry I do not have the Golem BOV here to compare with.

The mouthpiece test is the EN14143:2003 test, applied to just the mouthpiece with its mushroom valves fitted, but no hoses other than from the diver's mouth to the breathing emulator. This measures the worst case WOB at 40msw using air, at an RMV of 75 litres per minute with a tidal volume of 3 litres. We also include the EN14143:2003 calibration data (at 50msw, 62.5 litres per minute, as per the calibration point stated in EN14143).

For summary, the figures are:

• APD Inspo original: 2.64 J/L
• Draeger Dolphin: 2.06 J/L
• ISC Meg: 2.42 J/L
• DL O.R. SCUBA: 1.79 J/L

This includes some WOB from the breathing emulator itself. It emulates the work of breathing inside the diver. This should be included: with the calibration orifice the total WOB is measured at exactly 3.3 J/L. If you want to consider the device under test, without the work of the diver, then deduct 0.6 J/L at 40msw, or 0.72 J/L at 50msw. A final caution: though the resistance that causes WOB from the breathing emulator and device under test are serial, they do not necessarily add up linearly (the breathing emulator may contribute less out of the total, because WOB figures are the integral within the Lissajou).

The Lissajou figures we publish shown go the normal way around (i.e. as in NORSOK, STANAG, NEDU etc), opposite direction to EN14143. If you want the EN14143 image, mirror it (show it in a mirror).

Hope this is helpful in demonstrating how to do a direct comparison of different units, and present the results in a way that anyone can check for themselves if they have access to the appropriate equipment. The mouthpiece, counterlungs, scrubber, hoses and connectors are the parts that determine the total WOB of a rebreather.

We provide a full design verification report on the breathing emulator. You can see from the accuracy in which it tackles the EN14143:2003 orifice, it is pretty well spot on.

It is a very good thing for companies to test their equipment and publish the data. By doing this openly, we can keep each other honest: mistakes are easily made. Just to be clear, I asked for all these tests to be repeated over the past couple of days, and I compared the results with those we had obtained much earlier: they are the same. I personally witnessed and checked the test conditions, in addition to those named on the certificates. Thanks to Bob Davidov and Misha Soloviev for the drudgery of repeating these tests just so I could be double sure.

Alex

Attached Images

DL Mouthpiece measurements 080402.pdf (76.7 KB, 63 views)

caveseeker7

Thanks for the breathing figures, Alex, much appreciated.

__________________
Cheers
Stefan



"Political Correctness is a doctrine, fostered by a delusional, illogical minority,
and rabidly promoted by an unscrupulous mainstream media,
which holds forth the proposition that it is entirely possible to pick up a turd by the clean end.!"

AD_ward9

In reference to rEvo: Paul,
I need to correct myself. I misread your test conditions (when I wrote the above, I had them in my mind from another thread that the test pressure was barg but you state here it is bar absolute, at the correct pressure of 5 bar: 40msw).

At 3.15J/L at 5 bar absolute (approx 40msw) and 75l/min RMV, the rEvo fails to meet limit for WOB in EN14143:2003 - the limit under these conditions is, as you know, 2.75 J/L. It would also fail all other major standards and guidelines: NORSOK U101, STANAG 1410 with the 2007 NEDU limits, US Navy 1994 limits etc.

I understand your result is for the diver vertical position, which should be the worse of the two test orientations on the rEvo if the test has been carried out properly.

However, if it helps, all the other sports rebreathers also fail, except the Ouroboros, Sentinel and the Open Revolution rebreathers (both dual and single scrubbers).

It would seem only fair for CCR Ltd to update their comparison with your figure, and also put you in the right place of the table: at the moment even with your previous figure of just below 4J/L, your position in the CCR Ltd table was two columns to the left of where you should have been. Now you should fit between the Inspo and the Evo. CCR Ltd's table is below, for reference.

Just to keep things really fair, has anyone here got an Ouroboros that we can borrow for two weeks? The figure for the Ouroboros quoted in the CCR Table is less than we published for just the mouthpiece of the same gas dimensions as that on the Ouroboros, same bore, with extremely floppy mushrooms and large mushroom spider, large mouthpiece opening: in our case, I did publish the calibration data with the figures. However, I do not doubt that the Boris meets EN14143:2003 WOB limits - it should do comfortably. I will also publish the Meg and Inspo WOB at the same time as the Boris figures just as an extra incentive for someone with a Boris not in use every week just now. I will publish the curve for the WOB under the different loop volumes, as well as the Lissajous etc.

I should add that it is possible for an entire rebreather to have a lower WOB than just the mouthpiece, but the Boris design does not seem to have the feature needed for that. Anyhow, if we test one and publish the results, then we will have numbers that are in the open and directly comparable.

Alex

Attached Images

CCR Ltd figures on comparative WOB.png (58.7 KB, 199 views)

Dave Sutton

Alex,

How about the Mark-15 (with some reasonable DSV substituted for the Scott) and the CIS Mk-5P?


Dave

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"Silent Diving with No Bubbles and No Politics".... www.nobubblediving.com

AD_ward9

Mk-16 figures are fairly well banded about, and as they come from NEDU, are not disputed. The CIS-5P would provide interesting reference points, so someone has one in Europe or I can borrow it next time I am in the USA, I promise to send it back in one piece and with the data.

Mk-15 is wee a bit old : it became obsolete long before EN14143 came about. Like testing an IDA 60

Alex

Drmike

mk15 and mk15.5 wob test results

Rubicon Research Repository: Item 123456789/3525




@45m and 75 RMV

Mk15 w/standard Hoses and scott mouthpiece 5.3J/L
Mk15 w/redar(cooper style) Hoses and scott mouthpiece 4.1J/L
Mk15 w/AGA ACSC mouthpiece and hoses 2.44J/L
MK15 w/rexnord mouthpiece and mk16 hoses 2.29J/L
MK15.5 w/Rexnord mouthpiece and MK16 hoses 1.97J/L

@ 0.5% co2, 29 deg F

Mk15 211mins
MK15.5 346 mins


So what does this tell us?

This is what happens when experts in life support system design with a realistic budget and resources are used to design a life support system

This 20year plus design out performs all new units other than boris for wob

almost 6 hours scrubber life test results in 4deg C water - lol!

what can the others do? lol! and a WOB as good as the best currently offered (over 20 years later)

and people wonder why I still have my mk15.5!

Attached Images

compp.JPG (60.0 KB, 108 views)

__________________
Cave diving is a sport
Wreck diving is a sport
Diving in general is a sport

'Rebreather diving' is not a sport
its the delusional obsession with a highly dangerous and often inappropriate piece of equipment

caveseeker7

Like the Meg?

There should be one in the UK ...
NEDU also tested the MK-5p (and the Inspo) for NOAA, but results ended up in some obscure memorandum rather than a proper report. (that was the testing that Li battery warning originated from). Both WOB and duration were in that bloody memorandum, though.

That's like a dagger through his heart ...


Mike and RRR, thanks for the link and filing the report, respectively.

__________________
Cheers
Stefan



"Political Correctness is a doctrine, fostered by a delusional, illogical minority,
and rabidly promoted by an unscrupulous mainstream media,
which holds forth the proposition that it is entirely possible to pick up a turd by the clean end.!"

Drmike

old - but (the MK15 configured with rexnord hoses and dsv) has better wob than all but boris and a mk15.5 and a better scrubber life than most new units so....


Ive updated the chart accordingly

All hail the mighty mk15 series!

Attached Images

compp.JPG (60.0 KB, 109 views)

__________________
Cave diving is a sport
Wreck diving is a sport
Diving in general is a sport

'Rebreather diving' is not a sport
its the delusional obsession with a highly dangerous and often inappropriate piece of equipment