Overbreathing your regulator

[redacted]

I have not seen the regulator I can't overbreath - if I get silly enough. Chasing turtles at 60 fsw seems to work pretty well even with my Mk20/S600. My Mk2/R190 would get me to overbreathing in 1 to 2 knot currents. Cure is reduce your level of effort and catch your breath. Key is to know your limits so you will not be surprised when you exceed them. Knowing what is coming and how to handle it should allow you to avoid the panic that will cause real problems.

 

[LeFlaneur]

Aha, thanks for the info. I don't think I've ever experienced the feeling of not being able to get enough air out of my reg.

For me it is kind of the opposite problem. At times I seem to inhale too hard, and my reg continues to trickle air even after the inhale. A twist back on the breathing sensitivity knob rectifies this but I figure I'm probably being overly enthusiastic on my inhale and wasting air.

Not the same thing as "overbreathing" but probably related in that it is ineffecient breathing technique.

 

[Hank49]

In terms of what happens to the reg when one is overbreathing:
If it is a piston 1st stage, wouldnt the piston just stay open the whole time? Can anybody approzimate how fast one breathes when overbreathing?[/QUOTE

The piston stem pushes away from the seat when the pressure in the cylinder head is less than 140 psi or so (9.5 bar). This happens when you breath or press your inflator button. As soon as you stop inhaling the pressure reaches 9.5 bar again and pushes the piston stem down to the HP seat and stops the airflow. Over breathing occurs if you have a clogged screen coming into your reg from the tank or if the demand for air flow is greater than the opening at the hp seat can deliver, say if two people are heavily panting from the reg.....like if they were swimming from a large shark....or swimming toward a beautiful mermaid. And, unbalanced (OOOPS. BALANCED iI MEAN) piston regs generally have higher flow rate than unbalanced.

 

[MikeFerrara]

If the needle on your IP gauge is not moving, either the gauge or the regulator has got problems.

Some swing on the needle of the IP gauge is entirely normal even on a very high performance regulatorthat has just been serviced. In fact the drop in IP pressure is crucial as it is that pressure differential that causes the regulator to function.

While an IP gauge will and should drop some when you breath the SPG (HP rather than IP) should NOT. If it does it means that you're taking gas faster than it can move from the tank through the valve. A common cause of this is a valve that's not all the way open. Not good.

 

[simbrooks]

Not an expert on this, but the way i have had it explained to me is that there are generally two possibilities for the phrase "over-breathing the reg" to be used:
Mechanical - already covered to some extent above, the reg isnt balanced and as such cant cope at deeper depths, particularly with two divers sucking away - solution avoid $100-150 regs
Physiological - kind of touched upon, but not in a lot of detail. As you get stressed (by whatever, exersion, panic, etc) you start breathing more rapidly and shallow which doesnt flush our your CO2. The level of CO2 in your system is what makes you want to breathe, so as the level begins to increase as you produce it by breathing naturally (except it gets let our usually) and arent getting rid of it, you feel starved of air - causing you to breathe even more rapidly, nice downward spiral going on here. Solution - stop, breathe, think, act (with some more breathe put in throughout for good measure - but long and deep) to try to recompose yourself and flush that CO2 out - as slightly eluded to above. IMO this is the more common problem and people feel that they are overbreathing a good reg, when it is capable of delivering far more than they and a OOA diver might need.

 

[The Chairman]

There was a situation a few years ago in Blue Spring. After pleading with a group of divers to NOT bring lights into Blue Spring, two out of three did anyway... one light each. The third diver accompanied them down into the cave zone sans light. Once by cork rock, she had her mask blown off by the current which the other two divers failed to notice. At this point she hyperventilated and felt that she had completely run out of air. Since her "buddies" were doing their own thing, they failed to notice her quick exit out of the chamber. rapidly ascending @ 120 ft to the surface in a paniced flight, she found her self with "issues" on the surface. Scared, in pain, and completely freaked out, she called for help. A park ranger made his way down the embankment to assist her, and her buddies were up just in time to see the pair leaving the boil area. The ranger called for evacuation to a chamber (Florida Hospital) and soon she was on her way to recovery. The park then tried to investigate the light issue. It is my understanding that possession of these lights were denied and that they were not found. Based on the testimony of the injured diver, a citation was issued anyway.

BTW, the injured diver still holds to her claim of being OOA, even though she had over a 1000 psi in her tank. It was obvious, that the act of panic, coupled with a poorly performing low end regulator worked together to give her this impression. If you are ever curious as to my COMPLETE INSISTANCE to everyone abidingby the no light rule in Blue Spring. This could have been a complete tragedy that was easily avoidable by simply obeying the rules and avoiding a "trust me" dive.

 

[Seadeuce]

Having experienced the sensation of "Beating my Reg" more than once, I would like to state that, yes, the source of the problem can be mechanical, psychological, or both.
If it begins as mechanical it will soon become psychological.

The Stop/Breathe/Think/Act advice is solid, but I will add a bit here.

You can stop, close your eyes, talk to yourself (mentally of course), and while you're doing this you can help the breathing part by lightly pressing on the purge valve. This will give you a greater flow of air than would be deliverable at that depth, and will give immediate relief.

Not mentioned in the books, but then a lot of diving delights aren't.

Hope it helps someday.

Seadeuce

P.S. You must remember to do it at the time as well - not as easy as you might think!

 

[DA Aquamaster]

In terms of what happens to the reg when one is overbreathing:
If it is a piston 1st stage, wouldnt the piston just stay open the whole time? Can anybody approzimate how fast one breathes when overbreathing?

With an unbalanced reg, the orifice size is much more limited than it can be on a balanced design. In an unbalanced reg, a larger orifice means a greater change in IP as the tank pressure decreases. So as a practical matter, the orifice size is limited to a fairly small diameter to keep the IP change within tolerable limits. This is needed to prevent an excessive inhalation resistance from the second stage during a portion of the dive (the beginning of the dive with an unbalanced diaphragm reg and the end of the dive with an unbalanced piston reg). The smaller orifice consequently presents a limitation on flow rate.

One of the major advantages to balancing a first stage is the removal of most of the effect of tank pressure on the valve and the increased IP stability that results. The increased IP stability in turn allows an increase the size of the high pressure orifice and an increase in flow rate.

 

[scubatexastony]

over-balanced reg, made for deeper diving, sealed for better longivity and cold water diving. BTW, these regs actually increase the IP by 20-30psi on greater depths. i.e. 155-165 psi ^ambient

 

[matt_unique]

Having experienced the sensation of "Beating my Reg" more than once, I would like to state that, yes, the source of the problem can be mechanical, psychological, or both.
If it begins as mechanical it will soon become psychological.

The Stop/Breathe/Think/Act advice is solid, but I will add a bit here.

You can stop, close your eyes, talk to yourself (mentally of course), and while you're doing this you can help the breathing part by lightly pressing on the purge valve. This will give you a greater flow of air than would be deliverable at that depth, and will give immediate relief.

Not mentioned in the books, but then a lot of diving delights aren't.

Hope it helps someday.

Seadeuce

P.S. You must remember to do it at the time as well - not as easy as you might think!

Sometimes just for the hell of it I breath like this for a few seconds....hold the purge and pull the reg away from your mouth directly below of course. You have to be careful doing this in cold water as this may induce a real free flow from freezing.

--Matt