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

[mr_v]

You are looking at over a dozen colors just for standard gasses. That is without getting into the best mix crowd.

Color coding is a shortcut. It may also not be the best one -- there are colorblind divers.

Here is the real question: how might a life support system prevent a diver from breathing an unsafe gas in case if the diver did not perform a proper gas procedure? Industrial designers and human factor engineers have been resolving similar issues for decades. Scuba diving is lagging in that area mostly due to costs and conservatism. Think about the time it took to accept enriched air and rebreathers in caves.

 

[Manatee Diver]

Here is the real question: how might a life support system prevent a diver from breathing an unsafe gas in case if the diver did not perform a proper gas procedure?

Probably impossible, regs are too simple. But the DIR gas switch procedure with a buddy has three different checks that you are going to breath the proper gas. Two by the diver and once by the buddy.

 

[crofrog]

Probably impossible, regs are too simple. But the DIR gas switch procedure with a buddy has three different checks that you are going to breath the proper gas. Two by the diver and once by the buddy.

3 by the diver to verify mix. MOD label, gas analysis sticker and gas interruption check.

And you don’t switch until your buddy tells you he’s verified

 

[flymolo]

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.

I didn’t read all of these but the ones I looked at describe different use cases than the one being discussed here

 

[happy-diver]

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.

 

[Mobulai]

Could you provide a link to this?

I tgink it was blue hole instructor fatality — I’ll find the thread and edit with link

Error - Blue hole fatality

I came across a post on Chinese social media called 小红书 , but I couldn't find any corresponding reports in English-language news sources. According to the post, it appears that a Tech instructor was leading a group of students on a technical dive to the Dahab blue hole in Egypt. Tragically...

scubaboard.com

TLDR: instructor switched to/ has been using deco gas at depth (arch, 56~60m)

 

[iliketopetsharks]

So here is the problem, just in standard gasses you have nine different gasses.

Standard gasses:
32%
30/30
21/35
18/45
15/55
12/65
10/70

Deco only:
100%
50%

Many of the standard gasses will need two different colors one for bottom and another for deco. You are looking at over a dozen colors just for standard gasses. That is without getting into the best mix crowd.

You also need to factor in color loss at depth.

ETA: I forgot that the safe depths are also different for CCR. They typically go to the next deeper gas for their bailout.

This.
Now you'd need to memorize, or worse, make a note which color corresponds to what gas. And you're going to label the cylinder anyway, so what advantage would color-coding have?
And the comparison to hospitals, chemical plants, etc. is questionable. MOD is a 2 or 3 digit number, doesn't get much simpler than that.

 

[crofrog]

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.

Post some picks of your kit all setup for a technical dive

 

[SelfDiver]

Post some picks of your kit all setup for a technical dive

I have some gear pics on onlyfins
Trip Report - Bonaire shallow 50m dives

 

[eightytwenty]

I have some gear pics on onlyfins
Trip Report - Bonaire shallow 50m dives

This is weenie stuff. Replacing sensible solutions with convolutions at every step of the way.