Tank Valve Issue - Out of Air Incident

[AfterDark]

There's actually good reasons for backing off of full open 1/4 turn. Many industries do this. Just don't do it with a 1/4 turn valve!

Reason 1 - many valves can get stuck, i.e., they don't have a back seat, and as temperature / pressure changes, the valve can get stuck in the open position.

Reason 2 - when you check a valve open, having the 1/4 turn provides a positive indication that the valve is open. If you check the valve open and it's actually stuck closed, you'll think it's full open and go. 1/4 turn provides no restriction to flow through the valve. Though there are other checks that can detect a stuck closed valve, especially in single tank dives ... like no air ... but if your boat crew checked the valve for you on the way in and actually closed it ...

Very rare situations for which the 1/4 turn from full open has a potential safety impact but I'd rather the odds continue to be stacked in my favor whenever I dive.

Just some input from a novice diver but an experienced engineer.

Spot on. I was taught that 1st during dive training and then again in the shipyard where I worked for 19 years. Don't be surprised if the flaming starts. I was flamed by a few know it all's when I posted this in the past.

 

[boulderjohn]

T-mac: I was head down for a while (trying to photograph a particularly reticent critter)

A friend of mine was with a very experienced group doing a downward sloping swim through at the beginning of the dive when one of the divers signaled OOA. Like you, he was in a head down position. Later, they pulled the valve and found that there was no dip tube whatsoever, and the tank had quite a bit of water in it. When he had gone head down, the water had stopped the air flow. Of course, he had water in his reg as well, but the situation sounds very similar.

You will not hear the sound of a dislodged dip tube if there is no dip tube. Believe it or not, I know an extremely well known diver who does not use them because he thinks they just keep falling out and they are a PITA to replace. (Especially with doubles.) I do not share his belief, but it would not surprise me to find that leaving out a dip tube might occur more often than we would like to think with some operations.

 

[boulderjohn]

Apparently none of your studies have included accepting responsibility for your actions.

The problem comes when the attorney that the family of the deceased hires may have a different opinion about personal responsibility from yours, and a jury may agree that a paid dive professional should be expected to perform the normal role expected of a dive professional.

 

[Ayisha]

It does sound like a dip tube problem.

Friends of mine who meticulously maintain their regs were diving down south a few years ago and used their own regs with rental tanks. Suddenly for no apparent reason, one of them couldn't get any air when in a slightly head down position, which corrected when their head was up again. They opened up the reg after the dive and it was full of whiteish crud that wasn't there before. They knew the tanks were in bad condition and demanded that the tanks be vis'd/hydroed. One of the other divers in the group who didn't knowingly have his reg blocked took his reg home and maintained it and found the same whiteish stuff inside. They did tell me what the substance was, but I don't recall now. Besides the interior condition of the tanks causing blockages, they were also mad about the contaminants they were breathing all week.

There's actually good reasons for backing off of full open 1/4 turn. Many industries do this. Just don't do it with a 1/4 turn valve!

Reason 1 - many valves can get stuck, i.e., they don't have a back seat, and as temperature / pressure changes, the valve can get stuck in the open position.

Reason 2 - when you check a valve open, having the 1/4 turn provides a positive indication that the valve is open...

Spot on. I was taught that 1st during dive training and then again in the shipyard where I worked for 19 years. Don't be surprised if the flaming starts. I was flamed by a few know it all's when I posted this in the past.

Regarding doing the 1/4 turn back, I agree as well. I posted several years ago about my experiences when I decided to switch to leaving the valve fully on and had too many problems. People touched my valve and inadvertantly turned it off but I caught it since I check my own valve and watch the pressure as I breathe off it before I splash. I also had to keep explaining my decision to keep the valve open and got tired of it. Rick Murchison also posted about why it's better to do a partial turn back around that time. I rejoined the masses in turning my valve partially back.

 

[boulderjohn]

I rejoined the masses in turning my valve partially back.

Me too, if only a hair. I discovered that they can stick a bit when totally open, which can sometimes create a minor problem when trying to shut down in a hurry, as in a valve drill.

 

[Tool Belt]

The problem comes when the attorney that the family of the deceased hires may have a different opinion about personal responsibility from yours, and a jury may agree that a paid dive professional should be expected to perform the normal role expected of a dive professional.

....particularly if a witness sees you turn the air on and you perjure yourself at trial.........

 

[dumpsterDiver]

The problem comes when the attorney that the family of the deceased hires may have a different opinion about personal responsibility from yours, and a jury may agree that a paid dive professional should be expected to perform the normal role expected of a dive professional.

Is it the DM's responsibility to check every single divers tank valve before they hit the water? I'm not sure I understand your comment?

As for me turning the divers valve open when we were stuffing her onto the platform and before i knew if she embolized.... Well I suppose if I were asked specifically, I would say that I opened here valve to ensure that I could operate her BC, if she were to fall off the platform.

 

[Hatul]

Is it the DM's responsibility to check every single divers tank valve before they hit the water? I'm not sure I understand your comment?

As for me turning the divers valve open when we were stuffing her onto the platform and before i knew if she embolized.... Well I suppose if I were asked specifically, I would say that I opened here valve to ensure that I could operate her BC, if she were to fall off the platform.

I've been in situations where well meaning boat staff check my valve just before I jump in, and it always makes me a little nervous, as I'm afraid they could turn the handle the wrong way and close an open valve.

 

[Garth]

!!! Has anyone tried reaching their valve? Maybe you could try that?

 

[Hetland]

There's actually good reasons for backing off of full open 1/4 turn.


Reason 1 - many valves can get stuck, i.e., they don't have a back seat, and as temperature / pressure changes, the valve can get stuck in the open position.

Stuck open is better than not delivering gas. The vast majority of folks I dive with dive a fully open valve. Out of thousands of tanks, not a single one of them has reported their valve sticking open. I imagine that modern scuba tank valves are built a little better than they were decades ago.

Reason 2 - when you check a valve open, having the 1/4 turn provides a positive indication that the valve is open. If you check the valve open and it's actually stuck closed, you'll think it's full open and go. 1/4 turn provides no restriction to flow through the valve. Though there are other checks that can detect a stuck closed valve, especially in single tank dives ... like no air ... but if your boat crew checked the valve for you on the way in and actually closed it ...

or, you could just pay attention to your valve. Standard valves open in one direction.

Very rare situations for which the 1/4 turn from full open has a potential safety impact but I'd rather the odds continue to be stacked in my favor whenever I dive.

Thousands of tanks with no stuck valves, yet I've had a roll-off which resulted in no air. That 1/4 turn makes rolling off that much easier. Show me real examples of modern scuba valves getting stuck open, and I might give this a second thought, but again, a valve stuck open is better than sucking air through one that's closed.

Spot on. I was taught that 1st during dive training and then again in the shipyard where I worked for 19 years. Don't be surprised if the flaming starts. I was flamed by a few know it all's when I posted this in the past.

Hopefully you aren't taking this as a flame. I think "stuck valves" were more of a problem with scuba tanks years ago. If you've had a modern valve in decent condition stick, I'd love to hear about it.... It probably won't change my practice, but I'll certainly try to learn from it.

One of the other divers in the group who didn't knowingly have his reg blocked took his reg home and maintained it and found the same whiteish stuff inside. They did tell me what the substance was, but I don't recall now. Besides the interior condition of the tanks causing blockages, they were also mad about the contaminants they were breathing all week.

Aluminum oxide? Apparently there was water getting inside the tanks. Time to pick a new dive op, as they probably have compressor problems too.

Regarding doing the 1/4 turn back, I agree as well. I posted several years ago about my experiences when I decided to switch to leaving the valve fully on and had too many problems. People touched my valve and inadvertantly turned it off but I caught it since I check my own valve and watch the pressure as I breathe off it before I splash. I also had to keep explaining my decision to keep the valve open and got tired of it. Rick Murchison also posted about why it's better to do a partial turn back around that time. I rejoined the masses in turning my valve partially back.

I've had good luck telling folks not to touch my gear, but most of the ops I use regularly host tech divers... which means they probably understand not to mess with your gear when you tell them to. I've also never had someone question me about my valve preference, but if they did, I'd simply tell them it was my tank, and I was going to dive it fully opened whether they liked it or not.