An isolator is a must have. You are going to need it. I can think of more
reasons why you would want this option than to not have it.

You also need to at least double disk your valves. I completely plug mine or
triple disk them to avoid failure. The worst thing is showing up to dive and
not having gas because you have ruptured a disk. The first thing to usually
go is the o-ring. It will extrude upon the pressure being much to great. It
will go before a burst disk. I've seen it happen. The single burst disk is a
weak point in your gas supply. Double up your disks. No one is going to
check and if that is a problem go to a shop with people you can trust.

Chris

-----Original Message-----
From: Mat Bloedorn <mbloedorn@ya*.co*>
To: Mike Rodriguez <mikey@ma*.co*>; Sean T. Stevenson
<ststev@un*.co*>
Cc: Robert Wood <robert_wood@Mi*.CO*>; techdiver@aquanaut.com
<techdiver@aquanaut.com>
Date: Tuesday, February 23, 1999 6:13 PM
Subject: Re: Equipment Questions


>I know this has all been done before but.. Here goes...
>
>I agree that for hard core tech diving the isolator is the way to go.
>
>The isolator does however add some issues that the techical diver must
>be aware off.  We have all heard about instances where dives have been
>aborted etc, by inexperienced tech diver due to the isolator being
>closed, only one tank being filled at the shop etc.  The isolator also
>adds a common failure point should the actual isolator valve fail.
>These "human factor" problems I would suggest have an equivalent risk
>to the tank O-ring or burst disk.
>
>A properly maintained burst disk and tank O ring in my mind have very
>low failure potential during a dive (when the tank pressure is
>dropping).  The most likely failure point is during the filling
>process.  This failure mode I agree is not zero however. Not
>overfilling your tanks goes a long way to minimizing this risk.  Of
>course there is also the WKPP burst disk plug method although I'm not
>sure of the legality of this especially here in Canada.
>
>I think that all being said it is prudent to dive with a buddy if you
>are not using an isolator.  As a matter of fact it is probably a good
>idea even if you have an isolator.
>
>Mat.
>---Mike Rodriguez <mikey@ma*.co*> wrote:
>>
>> At 09:03 AM 2/23/99 -0800, Sean T. Stevenson wrote:
>>
>> >Robert, have you removed a valve knob and seen how large the stem
>is?
>> >This is not, IMO, a non-existent problem.  In addition to that,
>> >consider the possibility of tank neck o-ring extrusion... not common,
>> >but it does happen, as has been attested to by several list members.
>> >The isolator solves both problems.
>>
>> I once had a burst disk blow out during a dive.  The disk had
>> become corroded from exposure to salt water and was weakened
>> to the point where it failed during the dive.  Without an
>> isolator, it would have been a very unpleasant dive.
>>
>> As tech and cave divers, we go to such extremes with gear
>> redundancy, that it doesn't make sense to dive without an
>> isolator and run the risk of an extruded o-ring or failed
>> burst disk defeating the gear redundancy.
>>
>> -Mike
>>
>> --
>> Send mail for the `techdiver' mailing list to
>`techdiver@aquanaut.com'.
>> Send subscribe/unsubscribe requests to
>`techdiver-request@aquanaut.com'.
>>
>
>_________________________________________________________
>DO YOU YAHOO!?
>Get your free @yahoo.com address at http://mail.yahoo.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'.

Navigate by Author: [Previous] [Next] [Author Search Index]
Navigate by Subject: [Previous] [Next] [Subject Search Index]

[Send Reply] [Send Message with New Topic]

[Search Selection] [Mailing List Home] [Home]