Equipment failure and response: The free-flowing regulator

[AfterDark]

Very well done, thought out and practical post. Any one of those procedures can and probably would stop or slow down a free flow. Common sense with procedures and processes to build on.

If your plan is to kink the LP hose then you should install a OPV on a 1st stage HP port or the hose could possibly burst depending on the cause of the free flow. With a OPV open the bubbles would be behind you! Installing a inline shutoff valve works also, again OPV on a HP port.

My own SOP is to switch to my other regulator which is on a separate 1st stage and tank, either an ID setup or pony bottle and deal which the free flow in the same manner described by the OP and/or end the dive. Having an adjustable 2nd stage I also screw in the adjuster all the way in, sometimes that alone will stop it.

My SOP didn't come from my OW class it comes from years of doing and finding what's best for me not somebody else.

 

[TSandM]

You know, as part of Fundies, I had to demonstrate that I could reach and turn the valve on my single tank. It was very difficult to do, and required significant adjustment of my gear, as well as some changes in my exposure protection. I configure my single tank setup so that I CAN reach the valve, but there is no way on earth that I could feather the valve to allow myself to breathe while ascending. (I found that skill somewhat challenging in sidemount, where I could see and easily reach the valves!). I would not recommend any attempt to do that to a backmounted single tank diver. Sharing gas with a buddy, or making an ascent while breathing, either off the freeflowing regulator or your own backup reg, would definitely be preferable.

 

[scagrotto]

... then you should install a OPV on a 1st stage HP port

Assuming that OPV is an over-pressure valve, I think putting one on an LP port would be a better strategy.

The flow rate cannot exceed the exhaust valve capacity on a modern regulator. Stick your tongue in the mouthpiece if need be to modulate it.

That sounds like one of those things that's excellent in theory, but possibly problematic in practice. Even if the free-flow isn't a result of a too-high intermediate pressure, air is being uncontrollably delivered at about 140 psi over ambient. If that can empty almost 80CF in a couple of minutes I think the exhaust valve has to create some significant back-pressure. One thing that was definitely covered in my OW class was that alveoli can be ruptured by as little as 2 psi, so having air forced into my lungs is only very slightly more appealing than not getting any air at all. I like to think that my tongue is a highly skilled and dexterous tool, but I'm not sure I want to rely on it for such an important task without some redundancy, so keeping the reg in my mouth *and* having a good seal around it don't strike me as an ideal strategy. I'm inclined to think it's only a good choice when it's the only 2nd stage available.

 

[Searcaigh]

We were using the feathering technique with a stage last week during my Trimix class, works well.

Depending on exposure protection it can be difficult enough to reach valves on doubles, the thinner the wetsuit the better, never done valve drills with a drysuit though. With a bit of effort and use of left hand I can manage a single tank valve shutdown, but to feather the valve and breath off a FF second stage, that would be challenging.

 

[Makhno]

Ricky B mentioned pressing the purge button when not in the water -- but I didn't see any reference to the purge button during a dive (did I miss it?)

A strong current can cause a freeflow if the diver is facing into the current, because the water itself is pressing the purge button. Happened to my buddy on a hammerhead dive in a ripping current. He signaled that he had a reg problem (I could see that myself, but it never hurts to communicate) . . . I offered him my alternate, recognized the current pressing the purge button as the likely cause of the problem and signaled that he should put the palm of his hand across the 2nd stage to cover the purge button, so the current wouldn't depress the button anymore. He was agitated and upset and signaled "nah, **** it, I'm outta here" and upon his thumbs-up we aborted the dive.

He was not inexperienced at the time -- he was a recreational-level instructor and a novice tec diver with a couple hundred dives logged. It's curious how all that noise and all those bubbles tend to shut down calm, rational thinking.

Anyway, my main point was that if the regulator freeflows when you're facing into a current, try covering up the purge button.

 

[TMHeimer]

Several ways to breathe from a free flow. Another is cup hand (like open fist--make a hole), hold on mouthpiece, tip head to right and breathe. Whichever method, you won't swallow water that gets in the mouth unless you have (other?) airway control problems. Somewhat akin to breathing from a snorkel you haven't completely blasted clear.

 

[Agility]

For cold water diving two separate sets of regs (first and second stage) are standard in central Europe so that the freeflowing reg can be shut down to preserve gas and when donating air the load is still balanced between two first stages.

 

[flots am]

There is no reason to try and breath from bubbles, keep the regulator in your mouth unless you have an alternate. The flow rate cannot exceed the exhaust valve capacity on a modern regulator. Stick your tongue in the mouthpiece if need be to modulate it. Go up, the surface is your safety zone.

It always drives me crazy when people start describing all sorts of maneuvers for OW divers to perform in the event of a free-flow. It's Open Water. There is no need to handle every failure underwater. "Up" works just fine and there's all sorts of air on the surface.

The only one that's necessary is to continue breathing, surface normally with your buddy and share air if it becomes necessary.

As you said, it's not necessary (or even advisable) to remove the reg from your mouth. It's just air.

If it's annoying, blocking most of it with your tongue works fine. It's at the same ambient pressure it was before the freeflow. You'll just have more noise and bubbles.

---------- Post added April 21st, 2014 at 04:23 PM ----------

That sounds like one of those things that's excellent in theory, but possibly problematic in practice. Even if the free-flow isn't a result of a too-high intermediate pressure, air is being uncontrollably delivered at about 140 psi over ambient. If that can empty almost 80CF in a couple of minutes I think the exhaust valve has to create some significant back-pressure.

In a properly designed modern regular, it's impossible to get more air than the exhaust valve can handle. You can try it yourself in the pool if you want. Just press the purge button.

The same thing goes for BCs. Hold down the inflator and pull the pull dump at the same time. See what happens.

This isn't new stuff that nobody ever thought of before. It's engineered to work correctly.

flots

 

[TSandM]

The only reason I could see for a diver in manifolded doubles ever to have to feather a valve would be if BOTH regs froze, and stayed that way.

Sidemount divers or people using stages can see and feather a valve.

I don't think, given that this is in Basic Scuba, that the original author intended his remarks for people in doubles, sidemount, or carrying stages. He's talking about the traditional, back-mounted single tank diver. This person would have great difficulty feathering a valve, and is most likely not using redundant first stages.

 

[scubafanatic]

Ricky B mentioned pressing the purge button when not in the water -- but I didn't see any reference to the purge button during a dive (did I miss it?)

A strong current can cause a freeflow if the diver is facing into the current, because the water itself is pressing the purge button. Happened to my buddy on a hammerhead dive in a ripping current. He signaled that he had a reg problem (I could see that myself, but it never hurts to communicate) . . . I offered him my alternate, recognized the current pressing the purge button as the likely cause of the problem and signaled that he should put the palm of his hand across the 2nd stage to cover the purge button, so the current wouldn't depress the button anymore. He was agitated and upset and signaled "nah, **** it, I'm outta here" and upon his thumbs-up we aborted the dive.

He was not inexperienced at the time -- he was a recreational-level instructor and a novice tec diver with a couple hundred dives logged. It's curious how all that noise and all those bubbles tend to shut down calm, rational thinking.

Anyway, my main point was that if the regulator freeflows when you're facing into a current, try covering up the purge button.

Turning your head at a slight angle will achieve the same result, by reducing the 'effective' strength of the current that's trying to depress the purge button.