1/4 Turn on Valves - What are the various DIR agencies' take on this?

[WhiteSands]

This article explains why it is potentially life-threatening:

The Quarter Turn That Kills | Cave Diver Harry

An incident where someone actually died because of this:

Edgewater diver who drowned at Blue Spring still had air in tank | News-JournalOnline.com

What are the various agencies' take on this?

 

[Dhboner]

My valves are full open or full closed.

 

[WhiteSands]

Come to think of it, since the 1/4 turn SOP was devised to prevent damage to the valves (as you can't really tell if it's open or closed just by looking), this problem is quite easily solved.

You can just look at the SPG, and one can tell immediately if the valve is fully opened or closed. This negates the need for the 1/4 turn procedure.

 

[deadbilly]

OK, I'll bite.

You can just look at the SPG, and one can tell immediately if the valve is fully opened or closed

Nope. Try this: turn your valve on. Look at the SPG. Turn your valve off. Look at the SPG. Report back to us any changes that you may have noticed. (This admittedly snarky response has nothing to do with the quarter turn discussion, as to that: just don't do it).

 

[WhiteSands]

OK, I'll bite.



Nope. Try this: turn your valve on. Look at the SPG. Turn your valve off. Look at the SPG. Report back to us any changes that you may have noticed. (This admittedly snarky response has nothing to do with the quarter turn discussion, as to that: just don't do it).

I don't have a tank so can't try it, but I'm guessing it'll show pressure because of pressurization in the lines. Then just press the purge button for a second, then check the SPG.

 

[lindenbruce]

I open my valves all the way, the back them off from fully open by no more than a quarter turn. Reason is two fold. If for some reason my valve gets jammed in an overhead environment AND I have a need to close it down in case of a second stage failure the valve won't be jammed open from said impact. Granted this is very unlikely. Second, if for some reason I have to close a valve in an emergency and I happen to turn it the wrong way, the fact I turned it only a small amount before the handle stops will help remind me to turn it the other way to close it.

In both circumstances, if the valve is fully open and it gets jammed or in a sudden attempt to close it in the even of a leak, there is the possibility for the valve to get jammed open. Which could cause further stress adding to an already bad situation to begin with.

As far as Acetylene tanks go, the reason those get opened a quarter turn is for safety. If your have a fire between you and the tank, like from a failed hose or other connection, it is a simple act to close the valve cutting off the supply of flammable gas as quickly as possible. How that practice made it into scuba I have no clue.

Just my thoughts. B.

 

[eelnoraa]

In my DIR fundamental, we are specifically told to turn the valves on all the way, and don't do the 1/4 turn back from full open.

 

[Pullmyfinger]

This. ^

OP: You can reach back and check them.

 

[Instructor_Tom]

Back gas is open all the way!!


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[gsk3]

I'm pretty sure there's no official take on this, and that each instructor teaches according to their own teachings.