I have to ask: How many had a fire in their dry suit using 50%

[ajduplessis]

I doubt any possibility of a fire,but stranger things has happened.

Why would you be inflating from a deco bottle? I would also assume that when using 50 for this purpose you are ascending? Why the need to inflate if you are going up?

 

[KenGordon]

Because there is helium in the back gas and it is not good for staying warm in a dry suit.

 

[kr2y5]

I doubt any possibility of a fire,but stranger things has happened.

Why would you be inflating from a deco bottle? I would also assume that when using 50 for this purpose you are ascending? Why the need to inflate if you are going up?

See #9, the reason was to possibly avoid the added clutter of having to carry yet another bottle in a sidemount configuration, on top of other things that are already butt-mounted.

 

[boulderjohn]

I doubt any possibility of a fire,but stranger things has happened.

Why would you be inflating from a deco bottle? I would also assume that when using 50 for this purpose you are ascending? Why the need to inflate if you are going up?

I have learned through this thread that this is being done by some sidemount divers because of the difficulty of carrying a suit inflation bottle. I have never seen it done myself.

I assume it is because they do not want to inflate with the trimix they are breathing. I have had some recent thoughts on that.

I was taught to use a separate suit inflation bottle as soon as i started with trimix. I used argon when I could get it, but it was usually air. I used one on every trimix dive I did for years. A few years, I was setting up my gear on a dive boat during my annual winter stay in Florida, and I overheard a conversation next to me. They were laughing abut the fact that they used to use separate suit inflation bottles. I later took a stroll around the boat. Every diver except me was inflating with back gas.

When I interned on a trimix class pursuant to becoming an instructor, I had to fly to the location. I conferred with the instructor ahead of time about what I needed to bring, what I could rent, and what I could borrow. When I asked about the argon bottle, he almost laughed and told me to use my back gas. He did not own one, either for himself or to loan to me. We did all our dives using back gas, with mixes up to about 60% helium.

This past year when I was in Florida for that annual winter stay and got ready for my first trimix dive, I pulled out my full argon bottle and realized I had left the regulator in Colorado. I dived that day inflating with my back gas, and I did the same on every other dive that winter. I lived. Of course, all the above water temperatures were in the low 70s. Since then, my diving has been in the high 50s, and I have used back gas for that as well. No problem.

I suppose that if I were on a really long dive, it would make a difference.

 

[Akimbo]

The question came up in the context of cold water sidemount diving. There are not as many convenient places to carry tanks as in backmount. I heard of divers using deco gas to avoid the need to carry a separate inflation bottle to keep their configuration more streamlined. I have not heard (not until now) of anyone doing the same with heating equipment, though, hence the OP in the other thread.

Got it. I'm not sure about the value of heated underwear on a presumably long duration shallow dive (as imposed by a 50/50 mix), especially in moderately cold water (PNW). It strikes me that added insulation would be more effective overall than carrying enough battery power to last on that long of a dive. No active heating (ignition source) = no problem even with 100% O2.

 

[BRT]

I'm willing to bet that you could start a fire in a dry suit with 21% with enough ignition. You certainly could light your undergarments on shore with a match and no dry suit. Probably burn better at 100'.

 

[kr2y5]

Got it. I'm not sure about the value of heated underwear on a presumably long duration shallow dive (as imposed by a 50/50 mix), especially in moderately cold water (PNW). It strikes me that added insulation would be more effective overall than carrying enough battery power to last on that long of a dive. No active heating (ignition source) = no problem even with 100% O2.

True. Most people only use it during decompression due to the concern about failure (and the impact it has on decompression). One can also extend the battery life using a Pitkin, by keeping output at 30%.

 

[cool_hardware52]

Run your suit on back gas unless you are diving Helium Mixes. With He get a suit bottle and fill it with air or argon depending on how you want to believe about the benefits of Argon.

From a thermal stand point avoiding He is the key. I use argon, but I have a few 1000 cuft around for Tig welding.

Worried about redundant source of suit gas in case you have to shut down a post or your suit bottle fails / runs out? Add a LP hose to the other post, or use your wing LP hose to add a squirt and turn the dive.

Really paranoid? Add an oral inflate on the arm of your suit.

Kinda hard to see why you ever want to put deco gas in your suit.

Tobin

 

[sealark]

I always had my doubts about that story but we heard it during USN First Class Diving School in the early 1970s. This was not that long after the Apollo and EDU (USN Experimental Diving Unit) fires and a lot was being discovered and developed about proper oxygen handling. Obviously chamber fires were and are still the MAJOR concern.

Don't doubt it any more it happened in 1965 at EDU which was next to first class diving school I was in first class school shortly after the fire that killed divers. On my duty nights we spent a few hours in the chamber cleaning up the inside of the burned chamber. I was in class 1666. Washington Navy yard. Just reread your post I see where you posted about the fire at EDU, sorry

 

[Jack Hammer]

High humidity and dampness levels in a drysuit from condensation and sweat leave me less concerned about a %50 mix causing an explosion.