Free-flowing Regulator

[Dochueb]

...Now, what concerns me most is your comparison to drinking from a fire hose. Was that just an analogy as to the volume of air that you had to deal with or were you drinking water during the process? If you were drinking water, your technique has a certain amount of flaw in it.
-curt-

Indeed it was just an analogy. I didn't get any water to speak of.



The experience was more like: "This is a crap-load of air :icon10: -- kinda scary :11: -- I should probably start breathing now -- wait, I have been breathing -- kinda cool -- why am I not sucking water into my lungs and dying? :hanged: -- don't think such thoughts under water! :shakehead -- just go with it - you seem to be oxygenating your brain :brain: or you couldn't be having this internal converation with yourself -- kinda cool...:banana: "


Thanks for indulging my internal dialogue.

DocHueb

P.S. The Smilies were not present during the actual internal dialogue -- as this may have been a sign of that I was not, in fact, adequately oxygenating my brain...

 

[Damselfish]

ok, that gets my award for "Best use of smilies in a post."

 

[Web Monkey]

They all have one. It's on the tank, however when it's off, it's harder to breathe.

You can breathe a freeflow as long as it's running, then share with your buddy, however in very cold water, sharing with your buddy may cause his to freeflow.

In cold water, first stage freeflows are caused by ice buildup inside the first stage, caused by the expansion (and cooling) of air as it changes pressure from a few thousand PSI (tank pressure) to 150PSI or so (depends on manufacturer). The amount of cooling (and ice buildup) and the probability of a freeflow changes with the amount of air being used, so a first stage that was doing just fine with one diver, may or not be able to handle two without freeflowing.

Terry

here's a question or though ... does any manfucturer have a 2nd stage that the air can be cut off to stop a free flow without affecting the rest of the rig. It seems to me that a simple valve installed on the 2nd stage to cut off air would solve the problem.

 

[gdive]

That's because SSI does not list it as a required skill. The thought being why would you sip off of the primary if you have a functioning alternate by your side. I have taught breathing off the reg when I instructed for PADI and stress switching to alt when teaching SSI. However, I tend to agree MORE with the latter.

Hmm, funny this topic just came up for me for the first time last night. Breathing from a free flow reg was never mentioned let alone practiced in my OW (SSI)? I guess maybe I'll have to try one of these days at a safety stop.

On a side note, my step father was certified about 15-20 years ago, and he was mentioning some pool drill they did where one diver had to "catch" the bubbles from their buddy with a funnel and breath from that for a length of the pool?? While I'm sure it's an interesting party trick, I wonder where that would be usefull in the real world! Should I attach my funnel with a bungie, or a double ender? lol

Thanks,
Jason

 

[gdive]

Courious why you would not just switch to your alt and surface.

I had to abort a dive last weekend in Coz due to a free-flowing reg. I was 20 minutes into a dive at around 35 fsw. I took a breath and noticed that air was still flowing slightly when I stopped inhaling. After my next breath it started flowing. Fortunately, I'd been reviewing skills lately due to DM training, so it was not too big a deal (although I probably ascended a bit too fast -- my focus was on breathing from the fire hose rather than ascent rate).

So bottom line, it probably won't happen to you, but it's important to know how to respond if it does!

Dave

 

[gdive]

Slightly incorrect. It is NOT required by SSI nor is it listed as an optional skill on their slates.

The high pressure seat in all regulators is a thin piece of neoprene that seats against the brass cone. Failure of this part is not common but does happen in all regulators regardless of price or newness or having just been serviced. This causes high pressure air to go down the hose and the second stage to free-flow. The downstream valve design is done so the air will vent safely and still be breathable in the event of a high pressure leak. Which ever second stage (primary or octopus) that is tuned the most sensitive will free flow first. This is an important skill that is reqired by PADI and SSI among others. To delete it is a standards violation.

The instructor may also use the free-flow exercise to show how to properly vomit at depth. Another useful skill.

Breathing through a funnel, breathing from a tank without a regulator, breathing from a regulator without a second stage, BCD rebreathing, and buddy breathing with a snorkel for 200 yards are all skills that old timers talk about. So were pushups with weightbelts and tanks on. As well as surface dives with a wetsuit and no weights.

They are still great party games and such but have no place in entry level training.

 

[MikeFerrara]

Technique...

The sipping technique taught by some agencies is poorly thought out IMO. It requires you to use one hand to hold the reg so you can let excess air escape through your partially open mouth. You might need both hands to deal with things so just keep the reg in your mouth and let the exhaust valve deal with air you don't want. Stay horizontal and turn your head to the side so the bubbles don't knock your mask loose or something and so you can see.

 

[knotical]

In our classes we only simulate a free-flow, and do so by holding the purge button in. Since the hand is already there, it is used to hold the reg in place too.

A variant of Mike’s technique could be to hold on with your teeth and let your lips flop and act as a second exhaust valve. Maybe I’ll experiment with a doctored second.

I’ve been told, but do not know, that a worst case actual (not simulated) failure could deliver more air than could be handled by these techniques. The pressure in the intermediate hose is a hundred and some-odd psi above ambient, and a first stage failure could provide much higher pressure yet. In that case, I might be thankful I’m holding on to my second stage.

 

[Dochueb]

In the event of a high pressure seat failure - most common cause of an uncontrollable free flow...

If this is the most common cause, would breathing off the Octo work -- or would the Octo just begin free flowing as well?

 

[RP Diver]

If this is the most common cause, would breathing off the Octo work -- or would the Octo just begin free flowing as well?

If you blow a first stage seat, high pressure air is going to both seconds. That is why you are taught how to deal with it, because there is usually no other option but using it to get to the surface, or to get to your buddy's alternate. In cold climate freeze-ups, it may be different, but this is how it is taught in a responsible OW class.