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

[divezonescuba]

Given some recent technical diving deaths involving incorrect deco gas switches, the following video may be useful for some new technical divers. The most recent two are a technical diving instructor and a diver who attempted a deco gas switch while doing a deep air dive.

The video discusses additional measures beyond properly analyzing and labeling deco cylinders and following accepted gas switch procedures. These are extra measures that can be employed to minimize the possibility of an incorrect procedure in the event of an emergency or debilitated state such as narcosis.

 

[Tracy]

Or you could teach and use proper no tox procedures.
Just a thought.

Your video states that teams don't prevent switching to the wrong gas because a guy was diving with 9 students and did it wrong.
Diving with 9 students has nothing to do with team diving. They are practically opposite of each other.
Team no tox gas switches prevent breathing the wrong gas. Ignoring the procedures leads to accidents. A yellow hose isn't going to change that when it gets installed on a different bottle and you are used to going by color instead of doing a proper gas switch.

 

[mr_v]

@Tracy , I respectfully disagree with the spirit of "just teaching proper no tox procedures."

While some items in the video are questionable - I am not going to hunt for a yellow hose! - labeling regulators is on the right track. If you label tank/reg combos while analyzing the gases, a proper gas switch procedure becomes more streamlined. Typically, you'd switch the electronics first, then match perform the gas switch double verifying the gasses as labeled on the tank/reg.

 

[boulderjohn]

The most recent two are a technical diving instructor and a diver who attempted a deco gas switch while doing a deep air dive.

Could you provide a link to this?

 

[inquis]

I learned a long time ago about the concept of single-source information. *Assuming the primary record is easily accessible*, additional copies are useless at best and erroneous/misleading at worst. If the switch process cannot be trusted to simply look at the tank label, how can it be trusted to a) look at the regulator label and b) even install that secondary label?

NOTOX works. It has actually caught a below-MOD situation for me. (O2 was dropped next to my primary reel at 30 ft. On auto pilot, I started to switch when I arrived at the bottle but realized the error when steps 1 & 2 conflicted.)

 

[Tracy]

@Tracy , I respectfully disagree with the spirit of "just teaching proper no tox procedures."

While some items in the video are questionable - I am not going to hunt for a yellow hose! - labeling regulators is on the right track. If you label tank/reg combos while analyzing the gases, a proper gas switch procedure becomes more streamlined. Typically, you'd switch the electronics first, then match perform the gas switch double verifying the gasses as labeled on the tank/reg.

A reg is a reg is a reg. I can't count how many times a reg has had an issue at the dive site or on the boat and is immediately switched with another functional regulator. Outside of some having a bc hose installed on them, all of my stage/deco regs are the same and can be used for any purpose. They are not color coded specifically because they could be swapped for a different use and that would cause confusion.

Who teaches and why would you switch your electronics PRIOR to the gas switch?
A no tox switch verifies the regulator in your hand is connected to the tank you are reading the label on. A buddy check of the MOD verifies that you aren't reading incorrectly and have the correct tank. It is then turned on and you start breathing from it. Then you would switch your computer to the gas you are breathing.
When you are only carrying one deco or stage bottle, it is very easy to get complacent with the procedure. If you allow that to happen, consequences can happen in later dives with multiple gases.

Also, I didn't say "just teach proper procedures"
I said teach AND USE them.
Students emulate their instructor. Instructors with crap procedures generate students who emulate them.

 

[Capt Jim Wyatt]

I agree with @Tracy. I also teach and believe that the gas switch on the computer should be done after the actual gas switch is done. Universal NOTOX procedures when practiced in the water will prevent switching to the wrong gas.

Color coding hoses seems at first glance a good second line of defense. As @Tracy pointed out and as I have seen countless times hoses have to get changed at the last minute. So what was a yellow hose is now a black hose creating confusion. That colored hose change will have no effect on a NOTOX switch properly executed.

YMMV.

 

[Manatee Diver]

deep air dive.

Sounds like the first mistake right there.

 

[boulderjohn]

Sounds like the first mistake right there.

Yes, it does, and that is why I asked for a link to the story. I don't know of one like it myself--or maybe I have forgotten it. The recent tech instructor and student double fatality did not involve a gas switch, so he must be talking about a different incident.

 

[Pavao]

A reg is a reg is a reg. I can't count how many times a reg has had an issue at the dive site or on the boat and is immediately switched with another functional regulator. Outside of some having a bc hose installed on them, all of my stage/deco regs are the same and can be used for any purpose. They are not color coded specifically because they could be swapped for a different use and that would cause confusion.

Who teaches and why would you switch your electronics PRIOR to the gas switch?
A no tox switch verifies the regulator in your hand is connected to the tank you are reading the label on. A buddy check of the MOD verifies that you aren't reading incorrectly and have the correct tank. It is then turned on and you start breathing from it. Then you would switch your computer to the gas you are breathing.
When you are only carrying one deco or stage bottle, it is very easy to get complacent with the procedure. If you allow that to happen, consequences can happen in later dives with multiple gases.

Also, I didn't say "just teach proper procedures"
I said teach AND USE them.
Students emulate their instructor. Instructors with crap procedures generate students who emulate them.

Yes, this 100%.

Color coding is what is more likely to get people to switch to wrong gas, as Tracy pointed out, many of us have a bag of regs which all looks like, pick any they’ll serve the same function.

Color coding is bad because it leaves plenty room to poke holes in the procedure and make it fall apart real quick.

This is the first time I hear of switching computer before gas.

When I was teaching AN/DP with a single deco gas, the day of the first dive(simulated deco) I’d hammer into the students about properly labeling the cylinder, big stickers, MOD type, I’d mention that several times during our analyzing, prepping, briefing… it was intentional, because we would be bringing 50% to switch at 70ft, except that for myself, I’d sneak my O2 bottle, always in plain view for the student to have a chance to notice it at any time, bringing on boat, gearing up, the whole dive… then at 70ft when it comes time to switch I’d turn to them for the buddy verification, they’d always “ok” away for me to switch, even though the cylinder says “20 OXYGEN”, I’d do this to drive the point how easy it is to get complacent and robotic about it.