Heating systems - many deco risks?

Gobfish1

so much for my guarantees that it is completely safe,
well its nice to know there is some risk involved when I use it

thanks Alex

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Steve G

Apparently not the only gay diver in the village

http://drinkingliberally.org/blogs/o...nzee-glock.gif

http://www.scubatunes.com/audio/vol01/mp3/HiTech.mp3

AD_ward9

The heater was in salt water for several hours, inside its protective sack, rolled in a 5.5" diameter loop, then laid flat and operated again in salt water for under one hour. It was then put inside a counterlung and operated for 16 minutes, at which point it caught fire. The loop was filled with pure helium. There was no scrubber fitted and the loop temperature was under 30C. Nothing very spectacular, and nothing that should cause this sort of failure. It is not clear on the photos - our fancy lens are all away getting rechipped, but there were two separate regions that overheated enough to melt the plastic. One braid obviously got very hot, while the other braid was cold.

The tests were part of a series to control loop temperature for commercial diving applications. The first test was of external scrubber heating, the second test to control heat loss to the environment from the counterlung by heating the area between counterlung and counterlung bag, the third test to heat the gas in the counterlung by putting the heater in the counterlung itself and connecting it to a breathing machine. All tests were done on a bench: the maximum depth was about 1 foot, in artificial salt water. The unit was kept in a laboratory and not exposed to any freezing conditions. It was supplied direct from factory and had not been used previously.

The manufacturer has been advised. We are working with them and three other organisations, to introduce modifications to make the unit suitable for dive applications, both suit heating and control of rebreather loop temperature to maximise scrubber life and provide optimal temperature control of the breathing gas for "quite deep" diving.

What I am saying, is don't try this at home until a diving certified version of these products is available from a reputable company making dry suits for their business. Using motorcycle warmers for diving to keep your sensitive bits nice and warm, may cause a mime show underwater that gives out the wrong message on your proclivities .

Alex

Marc T

Hey DR JM "a cave diver hurted by a man-heater in a lot cave" sound like a nice first april joke
Hum or something like a severely burned cave diver
Well dont worry anybody the second one is for french ears only...but dont really know if the first one means anything for english ears

Richard Harris

Alex your photo is not of a Typhoon vest. Are you specifically saying you have discovered a fault with the Typhoon which is a dedicated diving unit?

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"Harry"

www.divedoc.net

nigelleggett

some divers in nova scotia have some success by using those muscle heating pads that go around your kidneys and by using your higher levels of o2 deco gasses the reaction is they heat up very nicely. a cheap solution!!!!!!

dive safe Nigel.

scubagrunt

i would personally avoid this as i have had these thing (in my gloves) go nuclear on me and I got burns. I was able to remove my glove and throw the thing away. now think of that happening in your drysuit and you cannot rip them off!! yuk. yes the higher PO2 causes the reaction to be greater. but i'm serious here it is not safe. also be aware that if you use argon in the suit they will not work well or not work at all (they need oxygen). safe diving.
mel

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mattwave

Yes I heard of a diver using the heating pad all over his body on a dive and used his 50% Deco Bottle for suit inflation. Boy did he have some bad, blistery burns.

On another note: wouldn't a warmer core temp equal more effeciant vascular circulation, thus better offgassing?



"Scuba like you love it"

AD_ward9

It is actually the material the Typhoon uses, and the problem that was found affects all other vests using electrical heating regardless of how they do it.

The manufacturers of the material are diligent in safety and we are working with them on a solution. Brute force solution, but a solution.

You need to be very clear what the Typhoon was made for: non-deco diving, where the diver can unplug it the instant it appears to be overheating. The material is not designed for deco dives or any environment where it cannot be instantly unplugged.

I personally would shelve any heating unit until the solution to this problem is out: during the most recent safety review of vest heating, dives and dive safety managers who used electrical suit heating in the later 1970s reported that people had 3rd degree burns back then (down to the bone), and nothing really has changed other than the cause of these burn outs has been identified. A lot of divers got permanent tattoos back then. A 3rd degree burn underwater is a serious matter. Why risk it when a decent undersuit works fine?

I do emphasise that a solution has been identified and is being implemented with all due haste.

Alex

Gobfish1

Alax

The Typhoon vest has a way of turning off, just disconnect from the power back,

Its on the out side of the suite ,

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Steve G

Apparently not the only gay diver in the village

http://drinkingliberally.org/blogs/o...nzee-glock.gif

http://www.scubatunes.com/audio/vol01/mp3/HiTech.mp3

AD_ward9

That is correct. That is why it has not been withdrawn I understand. Also for non-deco dives, people can go to the surface. The fire inside the unit would mean that it is not suitable for deco dives, because unplugging still leaves a severe burn.

Interesting comments from those who saw the 3rd degree burns on divers in the 1970s, that the diver did not realise they were cooking. They too had means to turn the system off. When the fire starts it burns the nerves, so the diver does not feel it after that.

Alex