Air break on rebreather, how to proceed?

[Agro]

How do you make air brakes on a rebreather? Do you switch to OC air? Do you change to low setpoint? Which setpoint? How long do you make air brakes, how long do you stay on high oxygen?

Theorie about deep stops, deco and air brakes seem to have changed. So I wonder what's state of the art.

 

[tbone1004]

I was really confused when I opened this up because I was thinking like a speed brake, than an air break. Very important distinction.

The most efficient way to do it is to switch to OC. Flushing the unit is fine if you have a mountain of oxygen available.

I run my units manually, so I don't have to "switch" setpoints.

Now. I follow 15:5 give or take a few minutes on each side. You can choose to either breathe the unit down with ppO2 that is going to drop naturally as your body offgases as well as consumes O2, you can do dil and o2 flushes to rapidly swing it, or you can switch to OC.

The important part is getting your ppO2 down as much as you can in order to help your lungs. I would argue that it's more important if you run really high ppO2's on your rebreather like 1.3/1.4 to make sure you're taking those air breaks.

 

[STIDVC]

I was really confused when I opened this up because I was thinking like a speed brake, than an air break. Very important distinction.
.

Thought the same !

 

[Superlyte27]

You don't need to do air breaks on CCR.

 

[tbone1004]

You don't need to do air breaks on CCR.

why not?

 

[The Chairman]

You don't need to do air breaks on CCR.

Every now and then, my loop gets so hot on my SF2, that I bail to get cooled down for a bit. Not a problem in a cave where I'm surrounded by appropriately cool water, but in the summer on a reef, it can get too warm for me.

 

[broncobowsher]

OK, so I am not the only one wondering what air brakes had to do with CCR?

The air breaks when sitting on deco sucking down 1.6 PPO2 diving OC, OK I get it. I am never at a PPO2 of 1.6 except for a brief moment when I am checking the O2 cells for current limiting. Just keep a 1.1ish PPO2

 

[Superlyte27]

why not?

Well, for a dozen reasons. But let's start with why you think you need to, and I'll counter those points.

Also, why do you think you really need air breaks on OC. There's one real reason and one reason that is BS.

 

[tbone1004]

Well, for a dozen reasons. But let's start with why you think you need to, and I'll counter those points.

Also, why do you think you really need air breaks on OC. There's one real reason and one reason that is BS.

even on CCR, my lungs and sinuses do not feel good when at the higher ppO2's for very long and I start coughing if I don't take them. It's worse with the dry gas on OC, but it still happens on CCR. Same reason air breaks are standard for chambers

 

[Superlyte27]

even on CCR, my lungs and sinuses do not feel good when at the higher ppO2's for very long and I start coughing if I don't take them. It's worse with the dry gas on OC, but it still happens on CCR. Same reason air breaks are standard for chambers

Valid reason. What PPO2 are you running? If you're doing the standard "Do not exceed 1.3 PPO2" that the training manuals say, you shouldn't have a problem. Although, individual physiology can very quite a bit. If you're running your PPO2 to 1.5 or 1.6 during deco, then yes, I could see the need for an Air Break, but I would stay on CCR, and just lower my setpoint.