Testing O2 Cells for Current Capacity

Genesis

Why not insist?

You can run a 0.9 even if it insists, since you can validate a 1.0 on the surface.

Its if you want to run a 1.2 or 1.4 that you need to prove hyperbaric PO2 readings first.

Going in negative is something I do on a somewhat-regular basis here too - but you don't need to validate every dive.

If the controller insists on a weekly validation your first dive after a week's layoff is going to be at a 0.9. When you reach 20' on the ascent you can validate with the O2 flush and now you've got hyperbaric capability back.

If you can maintain dilligence with some sort of surface testing regime (e.g. in a pressure pot) then that's cool too, but engineering prudence says you do not trust a sensor until you have proven that it can read beyond the range you want it to measure.

Current designs violate this maxim every day, and it simply isn't safe.

__________________
"A venturesome minority will always be eager to get off on their own, and no obstacles should be placed in their path; let them take risks for Godsake, let them get lost, sunburnt, stranded, drowned, eaten by bears, buried alive under avalanches - that is the right and privilege of any free American."
http://www.denninger.net
http://www.diversunion.org/liability.htm - Fix the Diving Cert racket

wedivebc

So Karl, ket me see if I have this. You are anti training and feel that our training system has completely failed to make Rebreather diving safer so you would rather make the RB units themselves idiot proof and they will be designed to protect us from ourselves.
Building idiot proof rebreathers will just create superior idiots don't you think?

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Cheers,

Dave....

Man is the only animal burdened with the knowledge he will eventually die

Genesis

First, I am not "anti-training". I am anti-force. If the failure to understand the distinction is due to lack of attention that is excusable; if it is due to other factors it is not.

Second, there is no such thing as an idiot-proof device, as Darwin continues to make more and more clever idiots.

However, proper engineering principles remain proper whether you're an idiot or not. It is not good engineering practice to design a device that allegedly relies on some measurement device without first verifying that the device can actually read over the entire range of interest.

That consumers accept improper engineering (because they don't know any better) speaks to the fact that we've given up in this country (and perhaps in the world generally) on critical thinking and analysis as a core part of any educational curriculum, and is sad. If consumers accept it knowing that it should be there - when it can be - then that's even worse.

If your device was not properly engineered to insist on "in-device" validation of measurement range than the only check and balance against this failure is for you, the user, to perform that test using something like a portable pressure pot on a set schedule. Given how simple this is to add to the contoller firmware I find this a particularly offensive omission - but heh, its your money (and life)

__________________
"A venturesome minority will always be eager to get off on their own, and no obstacles should be placed in their path; let them take risks for Godsake, let them get lost, sunburnt, stranded, drowned, eaten by bears, buried alive under avalanches - that is the right and privilege of any free American."
http://www.denninger.net
http://www.diversunion.org/liability.htm - Fix the Diving Cert racket