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12 boys lost in flooded Thai cave

Discussion in 'Accidents and Incidents' started by Dogbowl, Jun 26, 2018.

  1. Dan_T

    Dan_T Great White

    # of Dives: 500 - 999
    Location: Texas
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    1,711
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    There are some interesting discussions about this in previous posts, right above your post.
     
  2. Octopusprime

    Octopusprime Dive Resort

    # of Dives: 100 - 199
    Location: Chicago Suburbs
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    It does annoy me about the oxygen tanks mostly because they are confusing the subject when they talk about the oxygen levels dropping in the cave. I heard many people say why don’t they just open the oxygen tanks in the cave and we all know it is more complicated than that.
     
  3. Octopusprime

    Octopusprime Dive Resort

    # of Dives: 100 - 199
    Location: Chicago Suburbs
    473
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    I like many of the news affiliates say divers are there but not likely to participate. There is a big embassy attaché there mostly for PR so trump can take credit.
     
    chillyinCanada likes this.
  4. Dan_T

    Dan_T Great White

    # of Dives: 500 - 999
    Location: Texas
    3,548
    1,711
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    Not that much more complicated to me since they operated the oxygen tanks by venting the gas into the high humidity cave chamber. Although oxygen is an oxidizer gas, the air in the cave is wet. Suspended particle-particle impact in the wet air as the oxygen gas impinges to the surrounding air, would not create spark (static electricity) and any combustible material would be wet too. So, no heat and fuel sources to create a fire / explosion in the cave with the high level of oxygen.

    Also as the oxygen gas pressure in the tank drops, the tank temperature would also drop due to adiabatic cooling effect. In the oxygen tank filling station, they do care about the rate of filling up the oxygen tank as it would get hot as the pressure in the tank rises, due to adiabatic heating effect. Some of the oxygen filling stations put those tanks in cooling bath to control the tank temperature. Grounding the equipment is also important to avoid static electricity discharge during the filling process.

    They also use monel for valve internal instead of stainless steel for better heat resistance & non-sparking characteristic of the metal. Special lubricant is also used for the oxygen service.

    So, the usage of oxygen or air cylinders for this type of application makes no difference to me. The only difference that I can see is venting the 100% oxygen would raise the oxygen concentration in the cave at much faster rate than venting the air tank, containing only 21% oxygen. Carbon dioxide concentration would also drop accordingly by dilution faster with 100% oxygen tank than with air tank. Hence, using oxygen tank to increase the oxygen concentration in the cave is better than air tank and not more complicated either. Just open the valve & let the gas vent.
     
    Last edited: Jul 12, 2018
    DARK07 likes this.
  5. telemonster

    telemonster Barracuda

    # of Dives: I just don't log dives
    Location: Northern Virginia
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    One of the articles recently said they were diving 80% o2 during the rescue. So yea, mostly oxygen tanks.
     
    shoredivr likes this.
  6. kotik

    kotik Solo Diver

    # of Dives: 200 - 499
    Location: Houston, TX
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    Probably a little simpler still, and more effective, to just leave them a few O2 bottles to breathe from periodically. Venting it all out would probably do very little and for a very short time. Is there an account they really did it that way?

    Just putting myself in the shoes of someone that nearly killed themselves getting back there with extra gas, I would probably have a stroke if someone decided the thing to do is throw the valve open and dump it all out--
     
    Last edited: Jul 12, 2018
  7. falcon125

    falcon125 Nassau Grouper

    # of Dives: 25 - 49
    Location: Colorado
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    I'm sure we will see Documentaries, tv shows and movies galore about this. It is entertainment at its best. post 807 proves it.
    20/20 already did a piece and will do more. 60 Minutes will follow suit. BBC will have a great Documentary. PBS will have something. Every major studio in Hollywood is already planning their own movie. Then the cheesey tv movies will start to cover the story from every participants point of view until we are sick of hearing about it.

    Why is 19% oxygen not an oxygen tank? Oxygen is the primary gas needed so why the panty twist over Oxygen vs Air? When does it become an oxygen tank? 21% 36% 99.9%?
    First world problem for sure.
     
  8. Belzelbub

    Belzelbub Barracuda

    # of Dives: 200 - 499
    Location: Largo, Florida
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    For the same reason that a bottle of soda, or better yet, beer is not water. It's certainly mostly water, which is more than can be said for most of what the media commonly refers to as "oxygen tanks."

    There are certain purity requirements (depending on use) for a tank to be considered an oxygen tank. You were closest to that number with the last percentage you listed than any of the others.

    First world problem, yeah. Probably. But it's incredibly confusing when they use them interchangeably. Can't recall where, but early on, one of the media outlets was writing about Saman Kunan's death, and used both air tank and oxygen tank in the article. Only both were used incorrectly. The article stated that he was delivering an air tank and upon his return emptied his oxygen tank.

    Is it the end of the world? No. But in a rescue that relied so much on the expertise of divers, it would be nice if they made an effort to get the story straight. More recent BBC articles I've seen make me think that they've had a diver proofread their reports, as they've been pretty accurate. Even calling tanks bottles, which is common among divers, but not so much among the general public. Though, it's possible that's more common in Britain.
     
    Jarzi and FinnMom like this.
  9. Dan_T

    Dan_T Great White

    # of Dives: 500 - 999
    Location: Texas
    3,548
    1,711
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    Cracking open the valve to breathe periodically makes sense. I haven’t read any detail on how they used the oxygen tanks. Those large oxygen tanks have different fittings than that of Scuba tanks, so you won’t be able to connect Scuba regulator.
     
  10. Centrals

    Centrals Barangay Pasaway

    # of Dives:
    Location: Hong Kong
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    By your definition how would you call a tank of 32%O2?
    An O2 tank should only contain O2 and nothing else. This is certainly NOT first world problem. It is identification problem.
     

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