Accidental Detonation of CO2 Cartridge
JEFFREY WALL
>Security?? In what sense? The absolute _last_ thing you want to have
>happen when you are diving is have your bc inflate. I suggest that the
>amount of CO2 in the cartridge is much much more than enough to bring you
>up from any depth in a completely uncontrolled accelerating ascent. If
>you are in a decompression dive or not, this is extremely dangerous because
>you will definitely be exceeding the ascent rate while surfacing. You'll
>also run into the possibility of panic and holding your breath and causing
>air embolisms and serious lung damage. Equalization will be difficult if
>you have the sense to remember it on the way up. All in all, if you pop
>a CO2 cartridge while diving, you will ruin your day.
Not only does a CO2 supply security but it supplies redundancy. Your
suggestion that a CO2 will supply more than enough bouyancy from any depth
to bring you rocketing to the surface is wrong. The CO2 cartridge supplies
MINIMAL bouyancy below 15 - 20 feet. Let me supply an unlikely but possible
secanrio: You run out of air at depth, you then make a normal ascent
breathing off of your buddies safe second. Upon reaching the surface you find
that the wind has kicked up and the sea is rough. You have no air to put in
your BC. If you don't get out of the water soon you are going to get tired.
What do you do? The only alternative I see is dropping that expensive wieght
belt. Where as I could just pop my CO2 and still have the option of dropping
my weight belt.
>I'm rather concerned about the tone the previous post gives regarding the
>reasons CO2 isn't part of a BC anymore. From everything I've every heard
>from my dive instructors, the reason that CO2 was removed was that they are
>dangerous. Certainly saying that there's not enough air to fill the BC at
>depth is demonstrating a lack of understanding of the dangers involved. In
>fact, it give the impression that firing a co2 inflator at depth is a
>harmless but ineffective thing to do.
I'm concerned about the tone of the previous post regarding CO2 cartridges. If
someone detonates a CO2 at depth all that will result is a Psssst for an
instant. NO rapid uncontrolled ascents to the surface, and no embolisms. All
it is is physics. As pressure increases volume decreases and volume provides
lift. My instructor documented numerous cases where a CO2 could have
potentially saved a divers life. The only reason they were removed from BC's
is the manufacturers didn't want to deal with the liability if one refused to
detonate (due to lack of maintainance).
I won't dive without my CO2 cartridge. I gain redundancy and lose nothing.
By the way CO2's cost less than 20+ pound weight belts.
Jeff Wall
Rodney Peck II
>[...] You have no air to put in
> What do you do? The only alternative I see is dropping that expensive wieght
>belt. Where as I could just pop my CO2 and still have the option of dropping
> my weight belt.
[...]
>I won't dive without my CO2 cartridge. I gain redundancy and lose nothing.
>By the way CO2's cost less than 20+ pound weight belts.
Personally, I plan on losing the weight belt someday. As my dive instructor
said -- you shouldn't be worrying about how much money you spent on your
spiffy weight belt when it comes time to drop it.
Somehow, I think we had a different instructional experience. We all learned
the bob and inflate technique, and I've manually inflated my bc after a hard
dive in rough water just to see how difficult it would be. It's really not
_that_ bad. and finally, it doesn't take that much air from your tank on
the surface to inflate. Surely there will always be at least the amount of
air that a tiny co2 cartridge can hold.
But, I can see that you've thought this through and we have a difference of
opinion on what's most important and how dangerous the co2 cartridge is. I
suppose a good argument could be made that a power inflator is really
dangerous as well -- if it were to let go while you were down, you'ld really
be stuck -- worse than the co2 since there's a lot more air, and you would be
dumping your supply of breathing air out your bc's overpressure value faster
than you can breath.
It's all a matter of what you are expecting and what you are used to.
--
Rodney
Craig Campbell
>someone detonates a CO2 at depth all that will result is a Psssst for an
>instant. NO rapid uncontrolled ascents to the surface, and no embolisms. All
>it is is physics. As pressure increases volume decreases and volume provides
>lift. My instructor documented numerous cases where a CO2 could have
>potentially saved a divers life. The only reason they were removed from BC's
>is the manufacturers didn't want to deal with the liability if one refused to
>detonate (due to lack of maintainance).
>I won't dive without my CO2 cartridge. I gain redundancy and lose nothing.
>By the way CO2's cost less than 20+ pound weight belts.
>Jeff Wall
Lets all stop and take a deep breath for a second. It sounds as though this
thread is becoming a little less friendly. In an attempt to clarify, and
show that almost everyone who has posted is correct, I'll share with you
the history and fate of CO2 cartridges as I know it.
In the beginning, there was the horse collar. It could be inflated orally.
The manufacturer looked at it, and decided that it wasn't much good.
Then the manufacturer added to the horse collar a compressed gas cartridge
(CO2) so that is could be inflated without effort when nasty things were
occupying its wearer. The manufacturer looked on and saw that it was better.
(This design, basically, is still used on airlines for life preservers.)
When the young scuba diving community took the collar diving, it was initially
a safety device. (Bouyancy control was only discussed then in hushed whispers,
and J valves were trusted with divers lives back then.) The divers discovered
that, at depth, the cartridge would only go "Pssst for an instant" and the
collar remained mostly flacid. The divers thought this a rather poor state
of affairs, so they beseached the manufacturer for the improvement.
The manufacturer, hearing the plea's of the divers (and recognizing they had
$$$ to be spent) added larger cartridges to the collars. Early tests showed
that cartridges that inflated the collar at depth, caused it to explode at
the surface, so the manufacturer sat back, scratched his head, and added the
pressure relief valve. Now a vest could be fully inflated at several (I
actually forget how many, but ~ 100 ft rings a bell) atmospheres.
Later, the manufacturer, having heard the divers hushed whispers about
bouyancy control (no longer so hushed, I might add), added the auto inflator
to the collar.
Some time after that, the collar was re-disigned and reshaped into the vest,
and it was comfortable and very good. The vest had also inherited all the
features of the collar; auto inflator, pressure relief valve, and co2
overinflation cartridge. For a while, both the manufacturer, and the diving
community thought that it was very good, and it was dived with a lot.
Then, the accidents started occuring. For various reasons, including panic,
fear, fatigue, and accidental triggering, various vests were inflated at
depth and they did fully inflate. In some cases, the unwarry diver had even
ditched the weight belt as well. This resulted in great possitive bouyancy,
and the diver did ascend at a great rate and launch out from the water into
the sky (:-)). The diver community, and the manufacturer looked on and saw
that this was very bad. The hated embolism had found a way into the diving
community, and there was some thought that the co2 cartridge was to blame.
In fear of the demon embolism, the diving community turned its back on the
co2 cartridge, and did replace it with spent cartridges or mere plugs, or
bolts. The manufacturer seeing all this, and fearing the comming of the
litigation, also did shun the co2 cartridge from the scuba gear.
And the manufacturer looked on, and it was good. (At least for now....:-))
I hope that was at least mildly entertaining and enlightening. Basically,
some vests will only fully inflate at the surface, others will fully inflate
at various depths. The co2 systems were rejected because of the risk of
an uncontroled ascent. This risk was, in general, considered to outweigh any
bennefits of the co2 cartridge. (Because the cartridge over-inflated the
vest, it could not be effectively dumped fast enought to regain bouyancy
control. Hence, uncontrolable ascents.)
So, you see, depending on which vintage of system you are discussing, basically
everyone who posted was correct! (Smile, we're all friends again/still!! :-))
Now, obviously, different people will have different opinions, but the
consensus seems to be that a vest fully inflated with co2 during a 'bad'
situation will probably make things worse. With power inflators standard
equipment, a diver can (almost) always inflate the vest in a controled
fasion. If the cartridge will only inflate the vest at the surface, then it
could be argued that any diver should be able to manually inflate his vest
at the surface, in almost all situations. Or rephrased, the odds of the
auto inflator being unavailable, and the diver being unable to orally inflate
his vest are considered negligeble.
Hope this anti silts some of this water,
craig
David Duis
>[entertaining genesis of CO2 omitted... ]
>
>In fear of the demon embolism, the diving community turned its back on the
>co2 cartridge, and did replace it with spent cartridges or mere plugs, or
>bolts. The manufacturer seeing all this, and fearing the comming of the
>litigation, also did shun the co2 cartridge from the scuba gear.
My understanding of the reason for the demise was actually quite the
opposite. Discussion among the equipment manufacturers at AAUS
Biomechanics of Ascent conference in '89 clearly pointed to poor
reliability as the reason for discontinuation.
The problem was that the CO2 mechanism required maintenance, which
divers weren't doing, and therefore their CO2 detonators weren't
working. This was the subject of the "fearing of the coming of the
Litigation," and gave rise to at least one interesting experiment.
One of the folks involved in the discussion (his name escapes me) went
around on boats in California asking folks to detonate their CO2 --
he'd replace the cartridge on the spot. He said very few of the CO2
detonations were successful, and he did quite a few "spot checks."
Poor maintenance was the culprit, along with a few cartridges which
were already detonated (without the owner's awareness.)
People just weren't taking care of them, and as a result CO2
detonators are no longer considered suitable for the general (US)
diving public. This was in combination with the fact that CO2
cartridges aren't guaranteed to lift you from any depth, and the
causticity of the CO2 left in the vest -- folks were known to pass out
from a single full breath of pure CO2.
Note that none of the above says that CO2 detonators aren't useful for
those folks who take care of them. As always, there are a number of
exceptions to the behaviors of the masses. Personally, I prefer the
distinctly non-US mini-bottle approach -- maybe a Spare Air would be
useful with a CO2 nozzle adaptor?
Cheers,
Dave Duis NAUI AI Z9588, PADI DM 43922, EMT
du...@bent.esd.sgi.com Always check your Sources.
"I avoid this by periodically pressing down on the top of my head
and forcing the air out." -- Charlie Gibbs
Malcolm Weir
On a (slightly) related subject, for quite some time now I've been
wondering whether there's a market for an emergency lift device for the
little things that people take diving but don't want to get wet, e.g.
Cameras!
The point is that if you notice water seaping into your housing, you
naturally enough want to get the thing to the surface as soon as possible,
since there is a world of difference between a wet camera and a flooded
camera. The problem is that if you notice a leak while at a significant
depth, you really don't want to risk hurting yourself by ascending too
rapidly; on the other hand, you will naturally be anxious to get the thing
into lower pressures, to reduce the rate of leakage.
Enter the widget: I envisage a package not larger than (say) a regular
pack of playing cards, consisting of a small lift bag with overpressure
relief valve, a gas cartridge and a detonator. Possibly a minimal
regulator to prevent the lift bag from becoming too bouyant too
rapidly...
The lift provided would not need to be more than a very few pounds, as
most systems are pretty nearly neutral; in fact, for safety I'd not want
more than a few pounds anyway. This would also allow you to use small gas
cartridges.
You could even have the "rip cord" be attached to a couple of hundred feet
of thin line, so that when you fire the thing and watch several thousand
dollars of equipment rocket to the surface, you're left holding a line
attached to your pride and joy... so that when you finally reach the
surface, you stand a chance of recovering your (hopefully) damp, as
opposed to soggy, equipment.
Of course, with some housings detaching the ballast would achieve the same
effect, but my device would be soooo much more fun! Anyway, some housings
don't have any obvious ballast (e.g. some aluminum ones).
So what do you think? Does such a thing exist? Is there a market? Is it
feasible?
I'm ignoring the fact that in a large number of cases by the time you've
noticed that you've got a leaky housing, you've also become the proud owner
of an ex-camera, or an expensive pile of junk. The purpose of this device
is not to save the camera so much as to save the diver from rushing to the
surface.
Malc.
Nicholas J. Simicich
>Note that none of the above says that CO2 detonators aren't useful for
>those folks who take care of them. As always, there are a number of
>exceptions to the behaviors of the masses. Personally, I prefer the
>distinctly non-US mini-bottle approach -- maybe a Spare Air would be
>useful with a CO2 nozzle adaptor?
For reef diving, I've considered attaching my pony bottle to a first
stage and using it to fill my BC and operate my AIR II, while running
my primary off of my main bottle. It would eliminate one dangling
regulator, and still provide redundancy. The only problem will be
that I will have to refill my pony before every dive, maybe with a
transfer bottle. And I'll have to put a gauge on the pony reg. The
pony would be worn on the left side of my tank in that case, rather
than the right.
--
Nick Simicich - uunet!bywater!scifi!njs - n...@watson.ibm.com
SSI #AOWI 3958, HSA 318
Nicholas J. Simicich
>So what do you think? Does such a thing exist? Is there a market? Is it
>feasible?
Remember Sea Hunt? In Sea Hunt, there were inflatible rubber
balloons, held a liter or two, and gave a few pound of lift. You
squeezed them or did something, and they inflated. The pictures were
never very clear. You sent them to the surface as markers, had one
attached to your chest for emergency flotation, and did other
interesting things with them. Commonly used prop.
Dacor makes these, and they are still available. Rubber bladders are
attached to a standard CO2 mechanism, and you trigger the mechanism to
inflate them quickly. They are sealed, so that they can't dump (with
a liftbag, I'd worry about that). The bladder is rated to contain the
whole contants of the cartridge at the surface, so overpressure is not
a consideration. There are small ones and large ones, the big ones
trigger with two CO2 cartridges, as I recall. A friend of mine keeps
one attached to his Tekna scooter, so that he can dump it to the
surface in a hurry if it fails.
Anthony DeBoer
>For reef diving, I've considered attaching my pony bottle to a first
>stage and using it to fill my BC and operate my AIR II, while running
>my primary off of my main bottle. It would eliminate one dangling
>regulator, and still provide redundancy. The only problem will be
>that I will have to refill my pony before every dive, maybe with a
>transfer bottle. And I'll have to put a gauge on the pony reg. The
>pony would be worn on the left side of my tank in that case, rather
>than the right.
That sounds a lot like the setup I use for deeper dives, although in my case
the "pony" bottle has grown up, to an Aluminum 80 :-). The end result looks
exactly like double tanks, but without a manifold. I have my full regular reg
set on the right tank, with my drysuit inflator running from there, but
without a BC inflator. The left regulator provides BC inflation, a second
stage, and has a pressure gauge of its own. This way, I have two completely
independent, redundant systems, so no single point of failure should be able
to eliminate my air. If either system fails or has a freeflow, I still have
lots of air on the other side, and I have power inflation.
Part of the figuring behind this is for worst-case air requirements (at the
end of a dive, buddy with a single tank gets snagged on something and gets low
on air while we get things sorted out). I don't generally plan to use much
more than a single tank's worth of air, so most of the second tank is backup.
The other major factor is that the thing that bugs me about a conventional
manifolded double set is that after one dive, it's down to 1400 or 1600 psi or
so and it's really just a clumsy heavy single tank worth of air for the second
dive. With this setup, I use most of the first tank on the bottom, switch
regs when it's down to whatever safety margin I want, switch back near the
surface to bring the first tank down to 500, then only have to swap it for a
fresh tank and have 3000 and 2500 or so for the next dive. Swapping regs to
"optimize" air use is the only procedural thing to add, but that's not a
difficult thing to do, and I'd be watching my remaining pressure anyway :-).
--
Anthony DeBoer | "Another great thing about freshwater diving
NAUI AI # Z8800, DM # D5482 | is not having to rinse your gear afterward"
Geac Canada Ltd., Toronto | ade...@gjetor.geac.com | uunet!geac!gjetor!adeboer