Full on, and a little off

[PfcAJ]

Always turn valves (scuba tank valves included) all the way on, and then back 1/4 turn

...why?

 

[grf88]

...why?

To reduce the surplus population.

 

[NAM001]

I am speeking from being X navy. Many systems valves did not work well being fully open. steem valves would tend to stick against the (lets call it) the full open seat making it dificult to close the valve or give the impresion thta the valve was shut already. Now from the scuba aspect. checking the valve open ends up requireing attempting to close the valve and then reopening it to the stop. If 1/4 from open then checking is simply a 1/4 opening turn to verify. So the odds of having an open valve when going from 90% open to full and back to 90% is better than 90% to closed and trusting it was reopened. I have never had problems with 90% open valves in open water. HOWEVER i have had problems with 90% open and bumping and overhead and slowly closing the valve. I have had times when a buddy thought my valve was closed and opened it. In fact it was open and he closed it then backed off 1/4 turn and voila it breathed fine till bumped. I now use one rule fits all. I operate my valves and no none else. Valves are full open to the stops. The last check is just before sliding into the straps. When on boats with crew that changes tanks for me it does not work so well but one can find the process to insure you have a guarenteed unobstructed gas flow. BTW I use H valves for my backup for this situation. It has proved is worth twice so far. Every dive exposes a new problem and need for prevention.

Would love some genuine feedback on this...

"Turn the tank fully on and then one quarter/half turn back"..

That's what I was taught...

Why...?

 

[shoredivr]

Once again, an entertaining and insightful semi-annual 1/4 turn thread. This one has way more interesting marine/chemical/engineering info.

 

[PeterNBiddle]

A few people have died because people involved in each death (diver and buddy, possibly crew) forgot which direction to turn a valve to open it. Have I got that right?

If so, it would seem to me that the only way of addressing that specific issue would be for all of us to open valves all the way, count the number of turns it takes, then back in half those number of turns.

Then the valve will always be wide open. No matter who checked it / touched it last, and no matter how suddenly confused they've become about what direction a valve goes, the valve will be open.

 

[shoredivr]

I'll be leaving mine fully open, thanks.

 

[Trace Malinowski]

The quarter turn that kills

Fully open or fully closed. 100% right. Gotta love Harry.

 

[shoredivr]

BTW I use H valves for my backup for this situation. It has proved is worth twice so far. Every dive exposes a new problem and need for prevention.

I've found that if I have my single H Valve tanks, or my Sidemount tanks, nobody wants to mess wih them anyway.

 

[RTee]

Please re-read the article in the link.

From the moment somebody (with probably great credentials but I do not know him) writes an article and states that not only he does not care about differing opinions but that he will delete them, then I tend to give it less value.

I think one has to be careful when putting all the blame of somebody's death on a 1/4 turn procedure. To me it is like saying guns kill people. Guns by themselves very rarely (unless it explodes in your face) kill people. People do. Going back to his article...no mentions of valve drills which is practiced ad nauseum during tech courses involving doubles and no mentions of dive buddy either.

I was first certified in 1978 when the standard was valve fully open than 1/4 back. Nowadays, I go to full open and then just off the stop.

 

[Nemrod]

I know what was taught and backing an open valve off from the full open stop is not unique to SCUBA. It distinguishes a closed valve from an open valve. I have seen people close a valve that was actually open because it was hard to the stop and they thought it was closed. Not everybody is mechanical and knows the righty tighty and lefty loosey or even what it means.

I do it, I do not care what other people do.

N