Regulator Use in Cold Water

[Dustin_360]

Hi All-

I’m new to Scubaboard…. Anyway I have a question about using regulators in cold water. I recently purchased the Aqualung Mikron from my LDS. I was looking at the regulator and it has stamped on it >10C (which is 50deg F)

How cold can the water be while I can safely use this regulator? Do I really not want to use it in water colder than 50 deg F? Do I need to take into consideration outside air temp? At what point do I need a cold water reg?

I plan on doing most of my diving in warm places such as Arizona, Mexico and the Caribbean. The colder places I plan to dive infrequently are the Pacific in Washington State near Canada and the Atlantic around New York area. I’m wondering how late in the year I will be able to dive in the colder areas assuming I have proper exposure protection.

 

[Web Monkey]

Hi All-

I’m new to Scubaboard…. Anyway I have a question about using regulators in cold water. I recently purchased the Aqualung Mikron from my LDS. I was looking at the regulator and it has stamped on it >10C (which is 50deg F)

How cold can the water be while I can safely use this regulator? Do I really not want to use it in water colder than 50 deg F? Do I need to take into consideration outside air temp?

Cold-water freeflow is caused by ice forming inside the regulator (generally the first stage). The ice is caused when the pressure inside the first stage drops from tank pressure (3000PSI) to Intermediate Pressure (~140PSI), causing adiabatic cooling.

If the amount of cooling exceeds the amount of warming from the surrounding water, ice will form inside the regulator after the temperature inside the first stage drops below freezing. This usually causes the first stage to stick open, which makes the IP exceed the pressure rating of the second stage, causing a freeflow.

The problem is that the amount of cooling depends on how much air you're using. A 90 pound teenage girl might be able to use your reg down into the 40 degree range, while two panicked football players sharing air might end up with a freeflow at 60 degrees. Although there might be one, I'm unaware of any standard measurement technique or conditions for regulator temperature ratings. It might be something as unscientific as "The marketing department thought 50 degrees was cold."

At what point do I need a cold water reg?

Your second question is easy. If you plan on diving in any water that causes you to ask the question, then you need an actual cold water reg. You might be just fine with your current reg, until someone else has a freeflow or runs OOA and goes to you to share. Now you have two divers sucking on your reg, and at least one (maybe two) are hoovering at a pretty good rate. This isn't the time to find out exactly what the limits of your reg are. In a cold-water emergency, you want to know that your reg will be just fine.

Terry

 

[UncleJoes]

wow, awesome answer! Couldn't have said it any better!

 

[Dustin_360]

Web Monkey – Thanks for the explanation. It sounds like this is the exact opposite of what happens to air as it goes through a compressor. I looked on Wikipedia and there is a pretty decent article on the Adiabatic process.

On a cold water 1st stage what is done to prevent the regulator from sticking open?

If you have a non cold water 1st stage and it starts to freeflow because of the adiabatic process (in cold water)… Will that create a runway effect freeflowing the reg until all air is exhausted from the tank?

 

[rstofer]

The current theory is that environmentally sealed diaphragm regulators are the way to go for cold water. Some regulators have a special cold water kit.

Oceanic, for instance, states in the Owner's Manual that NONE of their piston first stages should be used below 50 deg F and that there are NO cold water kits that will work around the problem.

Some cold water first stages have, in addition to the sealed diaphragm, additional cooling fins (or heating fins, in this case). Some second stages also have cooling fins where the hose connects to the regulator internals. The more metal the better for second stages.

If the first stage fails and overpressures the second stage(s), you could get some pretty dramatic effects. I would imagine it could empty the tank a lot faster than you might want.

If you want to dive in cold water, get the right equipment. You just can't negotiate your way around the fact that some regulators do not perform well in cold water. They don't, they won't and they won't for you.

If you go to the AquaLung site, cold water regulators have a snowflake icon in the description.

If you care what the US Coast Guard, US Navy and NOAA chose for their cold water regulator, it is the Oceanic Delta 4/FDX 10.

If I were buying a cold water regulator, I would consider the ScubaPro Mk17/G250V. I did buy a couple of the DiveRite Hurricane regs.

But I just added an Oceanic CDX5 first stage to my old Oceanic Omega II second stages as I prefer these old regs.

Richard

 

[Web Monkey]

On a cold water 1st stage what is done to prevent the regulator from sticking open?

Some manufacturers like Atomic, pack the inside of the second stage with a non-freezable grease, and others maintain a slight positive pressure to keep water out. Some regs like diaphragm regs supposedly aren't (as?) susceptable to cold-water freeflows, although I've never actually looked into if it's true, or why.

If you have a non cold water 1st stage and it starts to freeflow because of the adiabatic process (in cold water)… Will that create a runway effect freeflowing the reg until all air is exhausted from the tank?

Yep. That's pretty much exactly what you get.

FWIW, it will freeflow until the cooling caused by the pressure differential is no longer sufficient to keep the inside of the reg frozen (as the tank empties, the cooling effect is reduced). Usually this is pretty close to "empty", but it can actually stop while there's some breathable air left.

Some people dive with doubles, so the freeflowing reg can be shut down and allowed to thaw, while breathing the other reg. OTOH, there's no reason the second reg can't freeflow too.

Terry

 

[tfsails]

To put it simply, you can use a cold-water reg in warm water and it'll act just fine. You can't do the reverse without running some risk of freezup.

 

[DevonDiver]

One very important consideration is surface or 'dry' breathing.

Many cold-water freeflows originate from icing that occurs before you enter the water. Primarily, this is because divers conduct a standard pre-dive safety check in cold air temps. Nreathing off a 'dry' regulator can cause the initial icing, which then becomes more severe as the dive begins, leading to freeflow on descent.

My advice is to postpone breathing from the regulators (to check function) until you are in the water and the 1st stage is submerged. This can be done at the surface, or just below the surface.

 

[Web Monkey]

One very important consideration is surface or 'dry' breathing.

Many cold-water freeflows originate from icing that occurs before you enter the water. Primarily, this is because divers conduct a standard pre-dive safety check in cold air temps. Nreathing off a 'dry' regulator can cause the initial icing, which then becomes more severe as the dive begins, leading to freeflow on descent.

My advice is to postpone breathing from the regulators (to check function) until you are in the water and the 1st stage is submerged. This can be done at the surface, or just below the surface.

No offense intended, but if the reg needs to be coddled like that, it's not up to the task. Emergencies don't happen at convenient times. If you can't stuff a reg in your mouth at any moment and breathe like you're climbing Mt. Everest, without causing problems, the reg isn't up to the task.

Although breathing on the surface increases cooling (actually decreases heating from the surrounding water), it really shouldn't be an issue. Not breathing on the surface prevents a great number of pre-dive safety checks, which include breathing on all the regs and checking that the BC and drysuit inflators work.

Terry

 

[reeldreams]

Delta 4 the new cold water reg
The National Oceanic and Atmospheric Administration announced its new regulator pick. In the June issue of Undercurrent, we wrote about NOAA's new rules and regulations for government divers in response to the death of two Coast Guard divers in Alaska last summer. One major change was giving the boot to all regulators Coast Guard divers had previously used for cold-water diving. After testing of multiple regulators, NOAA found Oceanic's Delta IV to be the most reliable.

"It consistently came up first for meeting all our criteria, and it won't freeze up in cold water," says Lieutenant Eric Johnson of the NOAA Diving Program. The Delta IV is an environmentally sealed diaphragm regulator and its first stage has Oceanic's Dry Valve Technology, designed to stop moisture and contaminants from entering and to prevent corrosion of internal components. NOAA bought 350 of the regulators and now requires its 500 divers to use that model when diving in water temperatures of 50 degrees or less. Johnson says the Navy's experimental dive unit is using them, too. The Delta IV is also commercially available for sport divers; Oceanic's suggested price is $570.

Cold-water divers should definitely invest in a good regulator that won't freeze up underwater. Two people died last April because of that problem. Jason Balsbough and Daniel Frendenberg, both age 21, and Sherry Eads, 43, went diving in a quarry in Gilboa, Ohio, where the water temperature was 38 degrees. Another diver called 911 to report the divers were down. Balsbough had regulator problems but was able to surface by himself. Frendenberg and Eads were too deep and their regulators were too iced for them to breathe.