Thread: CO2 bug
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Old 07-04-13, 09:33 PM   #31
Gryffon300
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Join Date: Dec 2007
Location: Perth, Australia
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Quote:
Originally Posted by Roger Dodger View Post
I logged the CO2 buildup last night.
0800: Dawn, dive to periscope depth, ahead 1/3.
1300: (5 hours) CO2 icon starts flashing. CO2 at 10%.
CO2 builds up 2%/hour.
2000: Dusk, surfaced, CO2 at 24%. 12 hours total time submerged. Battery at 76%.

I guess it was the flashing CO2 icon that got me spooked. CO2 becomes lethal if the percentage gets above 3%, so interpretation using a 100% scale is a might confusing. Will hydrogen gas bleeding out of the batteries also cause problems?
That sounds about right. I know this conversation got a little side-tracked about how long you can stay submerged vs the refusal of the bug to acknowledge that you had actually surfaced: which is what I assume is going on - a bit like the reverse situation when my Gallant Crew insists on staying on the bridge at 20 fathoms. (Only spotted that for the first time yesterday when I decided that to deny myself the pleasure of actually seeing all the brilliant graphics work that has gone into this game was taking the obsession for realism a touch too far. I won't use it for 'cheating', but while I'm creeping up on a target with nothing better to do, why not watch my boat ghost through the sea-grass?)

As far as your question about the operation of the 'Canary Gauge' is concerned, as Safety Officer, I should know this, but have never actually looked into it. I had assumed that it was calibrated to 100% equals 50% fatality rate (the usual measure of 'lethality'). So, I would think that the 3% concentration level that you mention is, indeed, the 100% point on the scale (after all, not much point showing the equivalent of 5 or 10% CO2 concentration, as it goes without saying THERE WOULD BE NO-ONE AROUND TO READ IT!

I've had a couple of confined space issues. Once when an arrogant Chief PO ordered a BIG Tongan welder down into a pit to clean it with no breathing or recovery tackle - it had been full of acid-based paint-stripper fumes, so, naturally, he collapsed. He wanted to order four more of his ilk down there (can you imagine trying to get one of those 300 pound warriors out of a hole in the ground?). They were going to do it too, until another CPO, who, thank the Powers, happened to be passing, intervened. I've never seen a screaming match like that, but eventually the idiot backed down and allowed the rescue team to do their thing with proper gear. Only one bloke in hospital for a week with respiratory and acid-burn issues, instead of 3 or 4 dead. Lucky. But, I've only had one encounter with CO/CO2

I was an idiot. Or, more kindly, ignorant of how quickly things can go wrong. It was winter in Sydney and we had no serious heating in the apartment. We naturally had all the ports & hatches fast-tight. We had a tiny Japanese Hibachi B-B-Q. We'd done some teppanyaki and gone to bed. I'd decided to just leave it to burn in the dining room for warmth. A couple of hours later, I woke with a splitting headache, like I'd never experienced before. I tried to wake my wife but couldn't get anything sensible out of her - she was in trouble, too. In my stupor, I was having great trouble working out what was going on.

Luckily, I fairly quickly figured out that it was the B-B-Q, so opened everything, and put the thing out on the balcony. It took us an hour or so to recover. I have no idea what concentration we reached (I still find it incredible that a couple of hands full of B-B-Q heat beads could generate enough to fill a two-bedroom apartment sufficiently to give us such a scare), but it certainly gave me a whole new respect for the Silent But Deadly class of Confined Space risks!

Gryff
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