Likelihood of reg freezing?

[DivetheRock]

I've been told that when diving in winter, or otherwise very cold water, that it may be advantageous not to breathe through it until you get it wet first. Apparently, during the winter mths. or during cold water dives there is a good chance that the condensation from one's breath will freeze inside the reg, causing it to malfunction (i.e. you don't breathe when your under - not a good thing to have happen!!!). Would someone experienced in this matter care to elaborate on this? Is there anything one may do to prevent this from happening? Any type of solution one may put in/on the reg to keep it from freezing which would not pose a health risk? - Obviously pouring a container of anti-freeze down the reg wouldn't help your lungs any. LOL
Where I dive the water is now down to about 48-50 degrees F, and will get colder. The problerm is topside, as well. Today the air temp was 2-3 degrees C, and will get much colder.
Thanks, guys.

 

[1_T_Submariner]

I don't think it is the condensate freezing, I think it is the temp drop in the regulator 1st stage from the pressure differential. I'm not totally sure however. Hopefully some Ice divers will provide more info.

 

[DivetheRock]

Yes. That's a good explanation of the problem, too, 1 T Submariner. I never thought of that. Like you said, it would be nice to hear from an Ice diver on this.

 

[Falco]

The problem with regs frezing is caused by adiabatic cooling caused by the drastic drop in pressure in the first stage. At a constant volume,a drop in the pressure of a gas will result in a drop in the temperature of that gas. Since the pressure of the gas in you tank is lower from anywhere from 2500psi to 3500psi to the intermediate pressure (usually around 130-140psi) of your first stage there is significant cooling effect on your first stage.

This phenomenon is accentuated when you are above water since air has a lower thermal conductivity than water, so as your first stage is cooled down (ie : using your reg on the surface), the air surrounding your first stage can't "absorbe" the cold emanating from your reg. Where as underwater (even when the water is nearing freezing point), the little heat contained in the water is transfered to the first stage thus "warming" it up.

The same problem can occur with your second stage. You can witness adiabatic cooling by fully opening the valve of a full tank, ice will form around the valve.

 

[TripletDad]

I'm not Ice certified yet (give me a couple of months) but I regularly dive in water below 40 (f) with my coldest being around 37. I have regs that are designed for diving in the extremes and have ice kits for them (with some luck I will even get them installed). If your regulator is designed for cold water then you shouldn't have any issues but if it is a warm water reg or even your average reg you may have some issues. Any good ice reg will have an environmentally sealed first stage so that water doesn't come in contact with any moving parts. If you know what make model your reg is that would be helpful. If nothing else, take it into a LDS and have them tell you if it is safe to dive. I have seen more people than I care to remember get free flows from regs not designed for the environment they are in and I have less than 100 dives. Usually it will happen by about 60' (20m) or so but it could happen shallower or deeper. Not only do you blow the dive for you and your buddy but you obviously risk injury.

 

[DivetheRock]

My reg is a Genesis GS2000, TripletDad. I'm not certain if this is for cold water purposes, but I'm going to try to find out. Perhaps I should also be looking into the ice kit you speak of, as well. Falco, excellent info. Thank-you. I'll do some more research on that condition, and hopefully we'll get more input here, too. Thanks.

 

[1_T_Submariner]

Thanks for the Explanation Falco. Not to Highjack the thread but, the USS Thresher was lost at sea due to many things one of them being that the Emergency Ballast tank blow valves froze up due to the same principle you described.

The problem with regs frezing is caused by adiabatic cooling caused by the drastic drop in pressure in the first stage. At a constant volume,a drop in the pressure of a gas will result in a drop in the temperature of that gas. Since the pressure of the gas in you tank is lower from anywhere from 2500psi to 3500psi to the intermediate pressure (usually around 130-140psi) of your first stage there is significant cooling effect on your first stage.

This phenomenon is accentuated when you are above water since air has a lower thermal conductivity than water, so as your first stage is cooled down (ie : using your reg on the surface), the air surrounding your first stage can't "absorbe" the cold emanating from your reg. Where as underwater (even when the water is nearing freezing point), the little heat contained in the water is transfered to the first stage thus "warming" it up.

The same problem can occur with your second stage. You can witness adiabatic cooling by fully opening the valve of a full tank, ice will form around the valve.

 

[DivetheRock]

1 T Submariner, this freezing is serious business...serious enough to take down a ship, hey. Geeez...was this a long time ago? You'd think they would be able to avoid such a small thing as this in such a huge vehicle.

 

[Scuba Brian]

i agree with falco on the science end of the reg system. I teach open waters into the fall here in minnesota and i have had at least one reg. per class freeze up and free flow(i only take students on fall OW dives after they understand problems that may arise). Keep in mind this water is below 50 degrees F. Rarely will a enviormentaly sealed reg. freeflow, in a sealed reg. water cannot get to the first stage instead water pushes on a diaphram triggering the function of thefirst stage, reducing the chance of a first stage freeflow. Running through the regulator is a heat exchanger that sticks out of the ends of the reg keeping the reg at the temp of the water( water even covered with ice is at least 40 degrees 37 or 38 just below the ice) keeping the moisture from freezing inside the reg. When you are trained in your open water class you are taught to exhale into your reg before you take a breath so you dont inhale sand or debrise that may have accidentaly gotten into the reg. When your trained to ice dive or dive in cold water your trained to inhale first allowing the reg. to adjust to the enviornment before exhaling moisture into the reg. Luckily regulators are a one way downstream system, meaning that if they do freeze up they will free flow instead of cutting off the air supply. Also if you are ice diving or in any overhead enviornment you'll need a redundant air system(pony bottle) also with a sealed first stage and a reg with a heat exchanger slung around your neck.

Hope this helps,

Brian Day
PADI MSDT#198541

P.S. I dive an APEX atx200 which is designed for extreme conditions.

 

[TripletDad]

A quick look on Genesis's site seems to imply that the GS2000 has the DAD system. If it does, that is a sealed system and you should be good. I would always recommend double checking with an expert but based on what I'm seeing it should be OK.

Good Luck