Doubles?

[super7]

What he say....................can you repeat that.

Nope.
But, if I have the whole procedure drilled in, it should be easy for me to write it out in a similar fashion.

 

[JeffG]

Some agencies, that I shall leave nameless, teach shutting down the post on the reg you are currently breathing first as statistically that is the reg most likely to fail. You then breathe the reg down and if the bubbles stop, the leak is in that reg. If not, you turn it back on and turn the other post off and breathe that reg down. If the bubbles stop this time, the leak is in that reg. If the bubbles do not stop, you close the isolator as the leak is in the manifold, burst discs or neck o-rings of the tank.

Thats the problem of learning on the internet.

You have the "nameless" agency procedure all wrong.

The problem with the above method in my opinion is that it works fine for small pleasantly bubbly sorts of leaks that pose no immediate threat of catatrophic gas loss. But for large leaks, you are going to waste an awful lot of gas before you get around to isolating and given that a ruptured busrt disc can empty a full set of doubles in about 3 minutes, you are potentially losing 1/3rd of your gas every minute and you may not have the gas to lose if the failure occurs at max penetration where you used 1/3rd getting there and will lose another third automatically in the tank with the ruptured disc or extruded neck o-ring. In that case, one half of the gas you loose before you isolate comes out of the only 1/3 you have left to get out of the overhead, so the sooner you isolate the better.

Given that your starting point is wrong...this is all just gibberish.

 

[texdiveguy]

Nope.
But, if I have the whole procedure drilled in, it should be easy for me to write it out in a similar fashion.

.................

 

[ianr33]

First of all, the most common leak requiring a shutdown is a freeflow - in which case you (obviously) just shut down that post and breathe off the other reg...
Likewise for any other "up-front" leaks - SPG, BC inflator, Dry suit valve, burst hose you can see, etc...
For a mystery leak - one you can hear but not see:

(1) Catastrophic leak - a sudden BIG leak (if a BIG leak isn't sudden you'll have already taken care of it before it gets big ) - Shut down all three valves.
(1.a) Leak continues - leak is either burst disk or tank o-ring or somewhere in the manifold - leave isolator closed, open both tank valves. Determine which side is leaking, breathe off the leaking tank until it is exhausted, then switch to the other tank; abort dive.
(1.b) Leak stops - leak is at first stage or beyond. Open primary valve.
(1.b.1) Leak resumes - shut down primary valve, open secondary valve and breathe off secondary reg; open isolator; abort dive.
(1.b.2) Leak doesn't resume - breathe off primary; open isolator; abort dive

(2) Leak smaller than catastrophic but more than "minor irritant" - shut down primary reg; breathe it down
(2.a) Leak stops - switch to secondary reg; abort dive
(2.b) Leak continues - open primary reg, shut down secondary, switch to secondary, breathe it down
(2.b.1) Leak stops - switch to primary reg; abort dive
(2.b.2) Leak continues - open secondary valve; isolate; determine which side's leaking, breathe that tank 'til depleted, switch to other tank; abort dive

(3) "Minor irritant" leak - be prepared to handle condition (1) or (2); abort decision depends on the dive.

The preferred team approach to a catastrophic leak on your buddy's system is to hand your buddy your primary while you do all the valve stuff.
If your buddy does that for you, great, but be prepared to do it all yourself.

Rick

That makes me really appreciate my new sidemounts

 

[mark99]

For a mystery leak - one you can hear but not see:

(1) Catastrophic leak - a sudden BIG leak (if a BIG leak isn't sudden you'll have already taken care of it before it gets big ) - Shut down all three valves.
(1.a) Leak continues - leak is either burst disk or tank o-ring or somewhere in the manifold - leave isolator closed, open both tank valves. Determine which side is leaking, breathe off the leaking tank until it is exhausted, then switch to the other tank; abort dive.
(1.b) Leak stops - leak is at first stage or beyond. Open primary valve.
(1.b.1) Leak resumes - shut down primary valve, open secondary valve and breathe off secondary reg; open isolator; abort dive.
(1.b.2) Leak doesn't resume - breathe off primary; open isolator; abort dive

The preferred team approach to a catastrophic leak on your buddy's system is to hand your buddy your primary while you do all the valve stuff.
If your buddy does that for you, great, but be prepared to do it all yourself.

Rick

This would be an efficient way to do it, but it requires the extra step of executing an effective air share prior to the shutdowns. I believe your goal is to save as much time=gas as possible. That would be accomplished by going directly to the valve shutdown routine (however it is taught) while still breathing your own backgas. If you fail to solve the problem in the shutdown sequence and lose all the gas, you can then execute the air share. For a major "mystery leak" (one behind your head) NAUI teaches to isolate first and then proceed to diagnose with individual valve shutdowns.

The other concern is that you would have one sequence if the buddy donated air to you and a different sequence if the buddy was not immediately available. IMO it's better to learn just one routine and have it drilled in so in a crisis situation it's automatic.

 

[texdiveguy]

Isolator is shut down first, then diagnose the issue, correct problem or shut down appropriate post and then re-open isolator if warranted. Keeping it simple.

 

[JeffG]

Isolator is shut down first, then diagnose the issue, correct problem or shut down appropriate post and then re-open isolator if warranted. Keeping it simple.

Works good when diving solo.

or you could

diagnose the issue, correct problem or shut down appropriate post.
If you cannot determine where the issue is coming from, shutdown right post.
If that doesn't fix it. Isolate and get help from team mate.

Assumption: You are diving as a team. If you are not, then the isolation first is a better option.

(this is one of those DIR procedures that should not be used in a non-DIR dive environment)

 

[Rick Murchison]

This would be an efficient way to do it, but it requires the extra step of executing an effective air share prior to the shutdowns. I believe your goal is to save as much time=gas as possible. That would be accomplished by going directly to the valve shutdown routine (however it is taught) while still breathing your own backgas. If you fail to solve the problem in the shutdown sequence and lose all the gas, you can then execute the air share. For a major "mystery leak" (one behind your head) NAUI teaches to isolate first and then proceed to diagnose with individual valve shutdowns.

The other concern is that you would have one sequence if the buddy donated air to you and a different sequence if the buddy was not immediately available. IMO it's better to learn just one routine and have it drilled in so in a crisis situation it's automatic.

I guess I wasn't clear. With a buddy it's a race to see who can get to 'em first. Most of the time that means the buddy sees the leak and you shutting down your valves, hands you his primary and takes over the shutdown/troubleshooting because he can see where the leak's coming from and you can't. You do not delay valve shutdown to effect an air share. The only change in the order of things would be because the buddy can identify exactly where the leak is and just set the valves properly without going through the ID steps.
My procedure with a major leak is to shut down all three valves immediately and then begin the troubleshooting process, which saves gas (statistically in a third of the cases) over shutting down only the isolator and then one post at the time... but on the grand scale of things that's a nit. If you want to shut down only the isolator and then commence the troubleshooting one valve at a time I wouldn't fault the procedure - even though I like mine better
Rick

 

[texdiveguy]

Works good when diving solo.

or you could

diagnose the issue, correct problem or shut down appropriate post.
If you cannot determine where the issue is coming from, shutdown right post.
If that doesn't fix it. Isolate and get help from team mate.

Assumption: You are diving as a team. If you are not, then the isolation first is a better option.

(this is one of those DIR procedures that should not be used in a non-DIR dive environment)

Or you could isolate on either solo or team dive. Isolate first, protecting 'your' gas is the first priority regardless of number of divers around you......we are always fling solo. Always seek out and accept team members assistance when needed. Do what works best for you in the situation....there are varying takes on this topic and they all have the same objective in mind.

 

[mark99]

I guess I wasn't clear. With a buddy it's a race to see who can get to 'em first. Most of the time that means the buddy sees the leak and you shutting down your valves, hands you his primary and takes over the shutdown/troubleshooting because he can see where the leak's coming from and you can't. You do not delay valve shutdown to effect an air share. The only change in the order of things would be because the buddy can identify exactly where the leak is and just set the valves properly without going through the ID steps.
My procedure with a major leak is to shut down all three valves immediately and then begin the troubleshooting process, which saves gas (statistically in a third of the cases) over shutting down only the isolator and then one post at the time... but on the grand scale of things that's a nit. If you want to shut down only the isolator and then commence the troubleshooting one valve at a time I wouldn't fault the procedure - even though I like mine better
Rick

Please don't think I'm being argumentative here, but I want to make sure people reading this thread understand that there is a big difference between our techniques in handling this emergency, and that they need to decide which way they want to go and practice practice practice ahead of time. I agree that the valve shutdown sequence is a "nit" as you say, and can be accomplished according to whatever protocol the diver learned. What is not a small deal is the idea that you are going to have your buddy actively attempting to diagnose your problem and shut down your valve(s). Personally the way I learned was that each diver only handled his own valves, and the buddy stood by to assist with an air share if needed. Of course the buddy could signal the diver in distress as to where the problem was if he could see it.

You can see how our different techniques could get us into some confusion if you were helping me with my valves and I didn't know what you were doing. So each doubles diver should make sure he knows in his own mind (and practices) the shutdown sequence, and communicates in advance with his buddy how this emergency would be handled.

Mark