Safety of radial vs axial scrubber

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gianaameri said:
O.K.

You WIN, I LOOSE.

Now please let us stay on topic.
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I'm sure you're not that loose.

But I guess my point is that, while numbers can be useful, it's impossible to quantify everything, nor is it always useful.

The temptation is to focus what can be measured, not what is important.

Janos
 
matt said:
What is the answer to these questions?
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Spieglehalter had recreational diving as a 1 in 250,000 chance of dying per dive. To put it in context, the average person has a 1 in 1,000,000 chance of dying on any one day. (A micromort).

I don't know what my own limit is.

Janos
 
Janos said:
Spieglehalter had recreational diving as a 1 in 250,000 chance of dying per dive. To put it in context, the average person has a 1 in 1,000,000 chance of dying on any one day. (A micromort).

I don't know what my own limit is.

Janos
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I'm thinking 42 is too low. I may have to reconsider that.

If I look at all the divers I have known over the years I'd say that totals about 100 regular divers. I'd say they do about 50 dives a year on average. Taking the entire period I have dived - that's 25x50x100=125,000. 3 of them are now dead. 1 of them not diving related. That's 1:62500. On OC, one CCR.

Cheers
Matt.
 
Janos said:
I'm sure you're not that loose.

But I guess my point is that, while numbers can be useful, it's impossible to quantify everything, nor is it always useful.

The temptation is to focus what can be measured, not what is important.

Janos
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Thank you thank thank you!:720icon:

Peter

Thread closed. Oh wait... Never mind.
 
Janos said:
I'm sure you're not that loose.

But I guess my point is that, while numbers can be useful, it's impossible to quantify everything, nor is it always useful.

The temptation is to focus what can be measured, not what is important.

Janos
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In a rebreather, WOB, Hydrostatic Imbalance, and Elastance are important to safety.

That is why I got involved in this thread.

Radial vs. Axial is important to safety.

Numbers don't lie.
 
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GLOC said:
That depends on the spin you put on those numbers and the questions they are answering ;)

Regards
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In statistics, it is true.

I do not like statistics.

Here they are measurements of the performance of the equipment.

Yamaha FZR 1000, 150 H.P., Kg. 220, 0-60 m.p.h. in 2.4 seconds - you can't spin those numbers (numbers off the top of my head from recollection).

Same for WOB, Hydrostatic Imbalance, and Elastance.

However, do you want to try and spin them?

Good-luck!
 
Temperature, air pressure, altitude, road surface, skill of user, tyres, fuel, engine service period, weight of rider....

It is all in the context.

;)
 
GLOC said:
Temperature, air pressure, altitude, road surface, skill of user, tyres, fuel, engine service period, weight of rider....

It is all in the context.

;)
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The optimal tested performance of the machine is unchanged by all the variables you list.

I am looking at the optimal tested performance of the Axial vs. the Radial as produced by the test-house.
 
But to define optimum you need to know the context and one context may be preferential to one system rather than another.

If you are going to compare apples with apples, EVERYTHING has to be the same, you also need to cover all the scenarios to ensure that over the whole spectrum of usage, apples are indeed being compared to apples.

Regards
 
GLOC said:
But to define optimum you need to know the context and one context may be preferential to one system rather than another.

If you are going to compare apples with apples, EVERYTHING has to be the same, you also need to cover all the scenarios to ensure that over the whole spectrum of usage, apples are indeed being compared to apples.

Regards
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The test parameters are those set and disclosed by the test house in the test report.

I am of a suspicious nature, but I do not believe the test house would deliberately try to produce numbers other than the optimal, for the tested conditions.

The test conditions would have to be identical to compare across rebreathers.

They are not. For example, the Meg uses 50 meters for the test in Air, while others use 40 meters.

So, if the Meg shines at 50 meters, it is likely it would produce even better numbers at 40 meters.

However, the test conditions for the Axial vs. the Radial for the Meg are identical.

Therefore, there is no reason to doubt the evidence supporting the conclusion that the Meg ISC Radial is safer than the Meg ISC Axial because it has a lower WOB and longer duration.

Equally, looking at a rebreather producing 2.75 j/l vs. the much lower NEDU limit, it is difficult to argue against the fact that it does not meet the NEDU limit.

Pick the numbers for the rEVO at 100 meters, and tell me what you conclude, to be concrete.
 
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gianaameri said:
In statistics, it is true.

I do not like statistics.

Here they are measurements of the performance of the equipment.

Yamaha FZR 1000, 150 H.P., Kg. 220, 0-60 m.p.h. in 2.4 seconds - you can't spin those numbers (numbers off the top of my head from recollection).

Same for WOB, Hydrostatic Imbalance, and Elastance.

However, do you want to try and spin them?

Good-luck!
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Just because it's easy to measure it does not mean it is the most important.

What is your own personal level of acceptable risk? 1 in 100; 1000; 10,000; 100,000; 1,000,000; 10,000,000?

"No numbers = Fairy tales"

Janos
 
Janos said:
Just because it's easy to measure it does not mean it is the most important.

What is your own personal level of acceptable risk? 1 in 100; 1000; 10,000; 100,000; 1,000,000; 10,000,000?

"No numbers = Fairy tales"

Janos
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R u Polish?

I already answered you a gazillion times on my personal level of acceptable risk.

ALARP - whether I drive a motorcycle, ride a bike, dive a cave, or fly to the moon (the latter no interest for now)...

I am not going to answer again the same question going forward.

As to what is important, safety limits (i.e. WOB, Hydrostatic Imbalance...) have been put in place by NEDU and others for rebreathers.

If you know better, and want to ignore them, hey up to you!

Your question comes at an interesting time because I am literally about to renew my sports insurance expiring 31/12/2012... should I get the "Basic" or the "Plus" as an ALARP diver?

I'll get the Basic.
 
gianaameri said:
R u Polish?
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WTF has that got to do with it? Enough of the casual racism please.

GA said:
I already answered you a gazillion times on my personal level of acceptable risk.

ALARP - whether I drive a motorcycle, ride a bike, dive a cave, or fly to the moon (the latter no interest for now)...

I am not going to answer again the same question going forward.

As to what is important, safety limits (i.e. WOB, Hydrostatic Imbalance...) have been put in place by NEDU and others for rebreathers.

If you know better, and want to ignore them, hey up to you!

Your question comes at an interesting time because I am literally about to renew my sports insurance expiring 31/12/2012... should I get the "Basic" or the "Plus" as an ALARP diver?

I'll get the Basic.
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You have said that you can't put a number on your personal level of risk.
Might there be other questions where it's not helpful to focus on the numbers but do adopt a different approach?

Janos
 
Janos said:
WTF has that got to do with it? Enough of the casual racism please.



You have said that you can't put a number on your personal level of risk.
Might there be other questions where it's not helpful to focus on the numbers but do adopt a different approach?

Janos
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It was a compliment, in your case! (meaning that you seem unable to comprehend English).

I suggest you ask RC as he may be a better communicator than I am.

I am unable to assist you any further on the subject matter.
 
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So, Matt, I answered all your pounding questions as well as I possibly could.

You did not answer mine.

gianaameri said:
What is the SIL level of your rebreather Matt?
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I believe it is "less than SIL 1."

I may add a column to the Database with SIL levels.
 
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gianaameri said:
I believe it is "less than SIL 1."

I may add a column to the Database with SIL levels.
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I don't think you will get many entrys in that column.

I know of only one rebreather manufacturer who claims to conform to IEC EN 61508 but they still don't deliver that particular product. As to the rest of the CE certified electronics, my guess is that they fulfill the demands on electromagnetic compatibility and the low voltage directive.
 
Oldefors said:
I don't think you will get many entrys in that column.

I know of only one rebreather manufacturer who claims to conform to IEC EN 61508 but they still don't deliver that particular product. As to the rest of the CE certified electronics, my guess is that they fulfill the demands on electromagnetic compatibility and the low voltage directive.
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I'd enter "less than SIL 1" for those which I have documentary evidence attesting to the fact.

For all others, I'd enter the SIL level from the Certificate (for what it is worth), if any.
 
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