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I understand the arguments for the "fully open" position, and the ones for the "partially open". It seems to me the fully open makes the most sense, but the discussion has sparked a question and a thought. I still back off on the isolator (as I do on all valves). That is, I open it all the way then back off so it's not "sticky" anymore. I assume everyone agrees that this should be done? The comment is about the design of manifolds. I understand why you would like a slow closing valve on the tank, since you might be putting O2 in the tank and because if you need to bleed the tank you will want to open it partially at first. However, on the isolator, I can't come up with any reason why you wouldn't want a fast on/off type valve. Since the isolator is always open, and you would close it only in the event of a failure (at which point you would want to shut it as quickly as possible), I don't see any drawback to a fast valve and only advantages. I'd appreciate some comments on the above by those who have more experience than I do. Thanks. Bruce Stewart wrote: ~ >Bob, > >The Iso valve is there for what its describes "Isolation", theres no >point in having it fully open as it acheives nothing. If you need to >isolate a cylinder and are losing gas then the quicker the better. >Remember when this happens every ounce counts. It can be confusing >only because the loss of gas is still happening from the failed system >half. The failed side should still be breathed till exhausted if one can. >Then hop onto what should be 50% of what you had when the failure >occured. The iso should be just cracked open to allow equalisation and shut >with the minimum of effort, come on think about this and get your head out >of the rubbish the agencies print. It is not common sense to have >the iso valve >fully open. Common sense is being familiar with the on/off directions of >all valves >and your buddies valves as well. > >Bruce > >At 07:55 PM 4/14/01 -0400, RDecker388@ao*.co* wrote: >>In a message dated 4/14/01 9:55:22 AM Eastern Daylight Time, >>rikard.lundgren@sw*.se* writes: >> >>> >As for the 3/4 of European divers using this method, divers taking there >>> first steps into tech training , do so with IANTD or TDI, >>> >, as shut downs are apart of syllabus, my instructor & people i have >>> listened to use this method, and as far as i a aware As the said >>> organisations are wide spread >around Europe , i can only conclude that >>they >>> are also shown this method. >>> >> >> >>I suspect this is more a matter of the individual instructor than what's >>actually in the standards. I've read both of these agency's standards at one >>time or another and do not recall a single line about requiring paritially >>open ISOs. >> >>Common sense dictates that all valves need to be either all the way on or all >>the way off. In a stressful situation requiring a valve shut-down it would >>be way too easy to turn the valve the wrong way if it's only partly open. >>With a strict on/off approach, the valve is only going to turn one way...... >>THE RIGHT ONE! Bare handed, gloves or mitts, shutting down a valve is not a >>difficult matter with a little practice. >> >>Bob D. >>www.SportDiverHQ.com >>-- >>Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. >>Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'. > >-- >Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. >Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'. -- Paul B. -- Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'.
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