Additional measures beyond analyzing, labeling, and notox procedures to help prevent incorrect deco gas switches

[rddvet]

What a stupid video. Colored hoses? Regulator labels? Seriously? This is like a time warp back to the ridiculous nonsense on the old techdiver email list 20+ years ago.

This guy isn't qualified to teach tech diving. I feel sorry for his students.

At this point I dont even have to watch his videos. I can just read the title and already know all the dumb bulls--t he's going to say.

 

[Pavao]

At this point I dont even have to watch his videos. I can just read the title and already know all the dumb bulls--t he's going to say.

Funny, as I remember having some interaction here on his videos some time ago, didn’t realize/remember it was his very first video, the bs started early.

Uploaded my first technical diving related video

Other than my artificially large looking abdomen, feel free to view and comment.

scubaboard.com

 

[Nick_Radov]

Okay then, I read through the thread, embarrassed to find I was active in it but did not immediately recall it.

The big discovery in this thread, if you go almost to the end to find it (post #48), is that evidently there was no switch to an incorrect gas on this dive. The diver was supposed to start the dive breathing from an air cylinder but instead started the dive--right from the surface--breathing his deco gas and continued with it to the bottom.

This is consistent what I said earlier in that thread--in almost every case I know of a diver toxing because of breathing an incorrect gas at depth, the problem actually occurred on the surface, usually because because of mismarked contents, and not because of a faulty gas switch at depth.

Right, which is why we follow the complete gas switch protocol on the surface if starting the dive breathing from a stage tank.

 

[Mobulai]

Yeah, like maybe? Can't solve a skills issue with gear.

The CCR has a HUD with lights, but that is too complicated.
I imagine a depth gauge with two lights

• zero lights = unit is off
• one light = unit is on but the depth is outside the set limits
• Two lights = unit is on and the depth is inside the set limits

Even in silty soup and mask off, you should be able to figure it out.

But seriously, assume a twinset with bottom mix, an AL80 with travel gas, AL80 with 50% and AL40 100% O2
That is not too many tanks to handle, but we see bad things happen. Task loading, ego, complacency, ego, fatigue, ego, communication breakdown, ego, denial, ego, hypothermia, ego and evenluck can all play a role in the accident chain of events.

Booth's law:
"The safer skydiving gear becomes, the more chances skydivers will take, in order to keep the fatality rate constant."

I can’t really say much about NoTox procedure and what is “the way” to do it properly— I’m very green on that front, I can count the number of times I did it (on a single 50% cylinder, nothing more) on both hands. I also know I can’t afford that on my regs, nor OC Trimix in sich a dive, that I will figure it out the CC way, and I would rather them “not very silty” (but who knows).

But I really do like that idea from a product design and functional saftey pov — it’s basically what I do, building autonomous systems for users that are expected to receive probable dumb input

I can see a version of the future where a “mild deco dive” can be enabled by tech for a DSD kinda diver — sorry for the horrors of liability for charter and daily boat crews, the future is scary!

 

[flymolo]

I can’t really say much about NoTox procedure and what is “the way” to do it properly— I’m very green on that front, I can count the number of times I did it (on a single 50% cylinder, nothing more) on both hands. I also know I can’t afford that on my regs, nor OC Trimix in sich a dive, that I will figure it out the CC way, and I would rather them “not very silty” (but who knows).

But I really do like that idea from a product design and functional saftey pov — it’s basically what I do, building autonomous systems for users that are expected to receive probable dumb input

I can see a version of the future where a “mild deco dive” can be enabled by tech for a DSD kinda diver — sorry for the horrors of liability for charter and daily boat crews, the future is scary!

There’s a quote from Terry Davis about complexity I’ll let you find it

 

[Mobulai]

There’s a quote from Terry Davis about complexity I’ll let you find it

I think I know which one you’re getting at — it’s an exercise in futility more or less, but my brain already started imagining it the moment it got mentioned and can’t I stop that part of my brain that does that daily (system design)
From a functional safety pov I wouldn’t sign off it, not without cell redundancy , code checks, and all the features that would make it very blown off and clunky and make it extra impractical
But still in a cyber punk kinda way, I like the idea — that it would be possible, not specifically how/why it would be used , just a side effect of being an engineer

 

[NothingClever]

@divezonescuba

First, a general observation.

I appreciate what your overall intentions are with these videos but it seems like you're developing your content without any peer or mentor review before publication. The reviews and comments you get are pretty damning but point to commonly-accepted procedures and proven techniques. However, it seems you have a stubborn streak in that you continue marching on publishing technical videos that get pilloried. It seems like the recommendations from other more experienced technical divers don't serve as any impetus to modify or evolve your approach.

There's good stubborn and bad stubborn.

Second, with regards to this specific video, although you say these proposed techniques don't replace a proper protocol, you spend all the listener's time on ancillary measures that a proper gas switch protocol gets lost in the extraneous.

Green mouthpieces < blink, blink > ?

If I'm not mistaken you were a Sapper. Would you ever for a second advise a young Combat Engineer to simply measure and mark lengths of time fuse for different non-electric breach requirements without conducting a burn test for the lot of time fuse you've been supplied with? Probably not. Because time fuse is hygroscopic, more than just snipping the first six inches, it should be periodically burn tested to account for the effect of absorbed moisture, too. Would you tell young Combat Engineers at the beginning of their tropical/sub-tropical coastal deployment they only need to burn test once in the beginning and from then on they can simply measure and take for granted the burn rate? Probably not. In both situations, you either end up with a premature det and WIA/KIAs or a delayed det and the loss of surprise with the same result - friendly WIAs/KIAs. What's the right answer? Test to confirm the rate of burn during pre-combat checks and ensure the breach team is using redundant ignition during pre-combat inspections to account for a possible failure during the assault. Marking the time fuse for burn times is a secondary technique but it is NOT the proper procedure.

I think you'd have been better served demonstrating a NOTOX drill and then at the end briefly adding some additional techniques you've developed but being realistic about how quickly your techniques can be rendered immaterial with predictable and likely changes in conditions. As it stands, the video could lead developing tech divers to rely on ancillary equipment solutions rather than focusing on deliberate procedural skills with second person confirmation.

I have never in 20 years of forum use ever had to put people on Ignore but ScubaBoard has totally changed my outlook. I hope you can improve your content so that I don't have to add you to that roster. Your intentions are noble but execution needs improvement.

 

[Manatee Diver]

The big discovery in this thread, if you go almost to the end to find it (post #48), is that evidently there was no switch to an incorrect gas on this dive. The diver was supposed to start the dive breathing from an air cylinder but instead started the dive--right from the surface--breathing his deco gas and continued with it to the bottom.

This is consistent what I said earlier in that thread--in almost every case I know of a diver toxing because of breathing an incorrect gas at depth, the problem actually occurred on the surface, usually because because of mismarked contents, and not because of a faulty gas switch at depth.

For some reason there are people don't do gas switch procedures on the surface. It is how we lost Andrew Ainslie two years ago, he started on his oxygen bottle instead of his stage.

 

[PfcAJ]

This thread is great. Get some popcorn.

Color coding is right. It is cost prohibitive to do it correctly.

NASA Preferred Practices already provide for color marking rationale
https://extapps.ksc.nasa.gov/Reliability/Documents/Preferred_Practices/dfe5.pdf


MIL-STD-1247
https://www.expresscorp.com/wp-content/uploads/2023/02/MIL-STD-1247D.pdf
Has a section (5.1.1) for marking different hoses with different colors.

Navy TABLE III. Titles and color codes for compressed gas cylinders
https://www.navyadvancement.com/assets/Docs/MIL-STD-101C.pdf
And Lawrence Berkeley National Laboratory Cylinder Size and Colour Chart Medical Applications (Praxair)
https://amo-csd.lbl.gov/downloads/Gas_Cylinder_Size_Praxair_Overview.pdf
US FDA 21CFR201.328 (Sec. 201.328) Labeling of medical gas containers
CFR - Code of Federal Regulations Title 21
The list goes on and on, but there is no rule on sport SCUBA cylinder marking.

NFPA color coding of breathing gasses highlights the issue with costs and labeling
NFPA Health Care Pipe Label Standards

It is a known problem that correct marking is an economic burden, even in professional healthcare facilities.
I am not making this up. this isn't just like my opinon dude.

Infinite funds would have the tank, first stage, hose, SPG, and second stage color coordinated.
In addition, each label should include min and max depth because it is being used in a pressurized environment.

Your slate (And $1,000 Shearwater) would have each gas switch color coded as well. The pressure transmitter should be able to determine if the diver is breathing the correct/wrong tank.
If we were doing this correctly it would be unthinkable strokery to use the GREEN 1st stage+Hose+SPG+2nd stage on anything BUT the green tank at the green depth.

Human factors engineering has already designed controls for these possible mistakes. The NO TOX procedure is a cheaper workaround.

The color coding Chris is proposing only looks insane to you because you are using a warped frame of reference.

Ever have to swap a reg underwater? I have. Instant breakdown of color code nonsense.

You’re switching to the *tank*. The reg is just how you get to it. This is why MOD works and everything else crumbles under real life conditions

 

[mr_v]

To recap the thread: A member proposes unconventional ideas to supplement a standard procedure, and everyone tells the member about how the idea is bad and will not work. All despite the fact that the proposal has roots in human factors and industrial design. Is it perfect? Probably not, but neither is groupthink.

Ya'll have a wonderful time!