Ascending faster than 60ft/minute

[Thalassamania]

Clearly stated, I've cut and pasted it to a file to use in updating some of my handouts, thanks.

 

[Fish_Whisperer]

Thank you very much, Bob. It sounds like Henry's Law goes hand-in-hand with Boyle's Law. Nice to see how it all fits together, physiologically, as well as in an applied physics sort of way.

 

[TheRedHead]

Re: Henry's Law. Curious about the collisions that Thal was talking about in relation to microbubbles.

 

[TheRedHead]

Thank you very much, Bob. It sounds like Henry's Law goes hand-in-hand with Boyle's Law. Nice to see how it all fits together, physiologically, as well as in an applied physics sort of way.

And don't forget Dalton and Charles....

 

[MXGratefulDiver]

Re: Henry's Law. Curious about the collisions that Thal was talking about in relation to microbubbles.

A simple analogy ... if you put some dish soap in a container and put it under a faucet, you will see relatively small bubbles forming. Over time, you will notice a larger bubble among all those smaller ones. It was formed by collisions between the smaller bubbles, which then combined into the larger one.

Similar thing happens in your body tissues if the microbubbles start to collide. Offgassing in a controlled manner eliminates the bubbles before they expand, which reduces the risk of those collisions ...

... Bob (Grateful Diver)

 

[TheRedHead]

Similar thing happens in your body tissues if the microbubbles start to collide. Offgassing in a controlled manner eliminates the bubbles before they expand, which reduces the risk of those collisions ...

... Bob (Grateful Diver)

Yeah, I know all that. Just finished Advanced Nitrox and know more than I ever wanted to know about gas laws. So are you saying that the bubbles collide and stick together to make bigger bubbles? That wasn't covered.

 

[japan-diver]

Do you have links to any study with actual data showing 60fpm was too fast?

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I am still out of the office diving a bit (big holiday week in Japan) so I don't have the links available right now but will try to pass them on a bit later. The more modern doppler studies have found significant more bubbling at a rate of 60ft than at slower rates. This has been pointed out in a few posts already. During Doppler studies rates of around 30-35ft per minute had the lowest bubble scores - avoidance of bubbles is what we want -even micro bubbles can lead to more serious problems if in a great number or if you are just unlucky.

Also NAUI has already implemented teaching a deep stop to all its divers for over a year now I believe, would have to check the training updates for exactly when the offical word was passed but it was some time ago. I know we have been teaching it for a couple years now after reading Weinke's work on ascent rates and RGBM theory.

 

[CD_in_Chitown]

So are you saying that the bubbles collide and stick together to make bigger bubbles? That wasn't covered.

That is what he's saying, after collision they converge into one bubble with the sum total volume of the littler bubbles.

 

[TheRedHead]

Thanks, CD...

 

[MXGratefulDiver]

Yeah, I know all that. Just finished Advanced Nitrox and know more than I ever wanted to know about gas laws. So are you saying that the bubbles collide and stick together to make bigger bubbles? That wasn't covered.

Yep ... and I'm surprised they aren't explaining it in Advanced Nitrox ... it's a fairly important concept ...

... Bob (Grateful Diver)