Reg freeze, accidents and procedures

[Patoux01]

Hey,

Got a few questions about regulators freezing up causing people to die and/or getting a ride to the chamber.
- Does anyone have "numbers" about how many accidents start with a reg freeze in his country (obviously a "cold water" country)?
- What procedures are taught in your area in order to deal with a frozen reg, both in NDL and deco dives?
- Any special equipment?


Before someone sends me off for training, I dive independent twins (sidemount) in cold (and/or deep) water and drysuit with "cold water" regs, so I should be fine . I'm just wondering what's done in other parts of the world. (note: regs don't often freeze in Australia, but it tends to happen in Switzerland where I'll go in 2 weeks)

Cheers

 

[TSandM]

I have no numbers, but freeze-related freeflows do happen here, because I've had one.

OW divers are trained to breathe off a free-flowing regulator. They are also trained to share gas. Either method should get someone through a free-flow.

I learned some ideas on how to PREVENT them after I had mine, like not breathing regs at the surface in sub-freezing temperatures, and using diaphragm regs that are environmentally sealed.

 

[BradMM]

...and using diaphragm regs that are environmentally sealed.

Sorry to hack your topic but this caught my eye. I would like to learn more about these.

 

[Dive Right In Scuba 2]

I'm not sure of statistics on this but TsandM summed it up well. Breathing from a reg above the surface when the mercury is below freezing is a big no no and a large cause of freeze ups. With you diving sidemount, if you manage your gas well it shouldn't be a huge issue if it did happen. Either isolate the offending cylinder, or feather it and breathe from it.

 

[Patoux01]

Oh I'm fully confident in my ability to shutdown a valve, it's not very hard (

). And my gas planning would probably be "I'll keep enough in each cylinder so that any of those can get me out of trouble".

It's just that some people have procedures and tank configurations that seem very strange to me. So I was wondering how it was handled in other places.
Their recommended procedure is: edit: using twins, y or H valve
1) If shallow-ish (~20m) and good vis
- switch to your backup regulator
- show your buddy the frozen reg
- have him shutdown the offending valve
- ascend, do deco as necessary
2) if deep (> 30m) and/or bad visibility
- sign out of air or go to him while breathing your backup reg
- ascend without closing the valve, while breathing off your buddy's backup reg.
- when reaching ~20m or better conditions, get the buddy to shut the valve
- end the dive, do deco as necessary

They also have kind of a ban on crossing hoses in your back (such as the typical setup for twins does). A "good cold water configuration" can be seen here page 16.
That configuration and procedure is not what is applied for the whole agency, only the recommendation of a few regions in France.

So I just started this thread out of curiosity to see what people around the world do and maybe get to compare procedures, if anyone is doing something different than "I close the valve of the frozen regulator and end the dive" (which is what I'd do both in backmount or sidemount).

 

[Michael Guerrero]

One of my deco regs free flowed once. I feathered it for the 20 minutes or so I was on the bottle. One of the situations where you can't just end the dive. Harder to do with a backmount tank.

 

[swimmer_spe]

On my final OW check dive, my reg freeflowed due too a frozen first stage reg. It actually had ice on it.

I had purchased my gear prior to thee course, and prior to learning about what a cold water reg is.

 

[Searcaigh]

Oh I'm fully confident in my ability to shutdown a valve, it's not very hard (

). And my gas planning would probably be "I'll keep enough in each cylinder so that any of those can get me out of trouble".

It's just that some people have procedures and tank configurations that seem very strange to me. So I was wondering how it was handled in other places.
Their recommended procedure is:
1) If shallow-ish (~20m) and good vis
- switch to your backup regulator
- show your buddy the frozen reg
- have him shutdown the offending valve
- ascend, do deco as necessary
2) if deep (> 30m) and/or bad visibility
- sign out of air or go to him while breathing your backup reg
- ascend without closing the valve, while breathing off your buddy's backup reg.
- when reaching ~20m or better conditions, get the buddy to shut the valve
- end the dive, do deco as necessary

They also have kind of a ban on crossing hoses in your back (such as the typical setup for twins does). A "good cold water configuration" can be seen here page 16.
That configuration and procedure is not what is applied for the whole agency, only the recommendation of a few regions in France.

So I just started this thread out of curiosity to see what people around the world do and maybe get to compare procedures, if anyone is doing something different than "I close the valve of the frozen regulator and end the dive" (which is what I'd do both in backmount or sidemount).

I have to say that I was a bit confused by your procedures until I saw the valve on the tank via the link.

For me that type of valve is not common, in reality I have only seen them in Spain and most of the time they are arranged so that one is a DIN and the other for standard A-clamp first stage.

Personally I prefer diving twins, at least the redundancy factor is there and the valves are easier to shut off without help from a buddy.

 

[Patoux01]

For me that type of valve is not common, in reality I have only seen them in Spain and most of the time they are arranged so that one is a DIN and the other for standard A-clamp first stage.

Edited.
Yes, they're quite common in France/Switzerland, I think Belgium as well. They often use them with 2 DIN valves however.

 

[Redshift]

I dive with a twinset, so in case of a regulator freezing I shut down that one and breathe from the other. It will eventually defrost and be operational again.

The configuration is always the same. I didn't read that manual you shared, but their hose routing is for a single tank, so not sure they'd change it also for doubles. Maybe they want a clear distinction between right and left to better recognize which valve to shut.

From what I have seen from the PADI specialty, keep breathing from the free-flowing reg (at least you are using some gas and not wasting it all) and go up. They are attached to a rope, so it's pretty fast to be pulled out in an emergency if needed.

To prevent freezing, as others have said, environmentally sealed regs (although at least here many people also have Mares without sealing and they seem to cope well with cold water), no breathing on the surface, definitely, no purging. Also, some people lower the IP of the first stage.

Not related to regs, but remember to open your suit after the dive before the zipper freezes