High pressure hose blowing, can it happen UW?

[Groundhog246]

The HP orifice is tiny, let's say the size of a #80 drill bit which is .013" in diameter. This means the hole is about 0.00013 sq in. Let's say an LP orifice is .25" across which gives an area of .049 sq in. The LP port at 140psi would move about 17 times the air as the HP port at 3000psi.

But the LP port will stay at 140PSI till the tank hits less than that, the 3000PSI will drop to 2000PSI and lower the volume moving through the fixed size orifice.

The original question was "can it rupture underwater?". And the answer is yes, it can and it does, but not all that often. The second part was, "what happens?" And what happens, it empties the air out of your cylinder, but not all that rapidly.

The unasked question was, "Should I buy my own reg to prevent this happening?". And I'd say, buy your own reg so that you know it maintenance history, characteristics, etc. I'd put owning my own reg ahead of owning a dive computer or BC. I do lean towards buying your exposure suit first, as it's hard to get a good fit all the time with rentals and often half the rental price for an equipment package is the wetsuit.

 

[s7595]

hose's and injury .in my job for the last 28 years I work daily with 3200 psi hoses and to my knowlage only 1 person was ever hurt ,he had the hose wraped around his body and it blew. my point is if scuba hose is as good as airless paint hose that I have over 10 years of use on ,then relax zero to nill chance of blowing.now if you are in wrecks all the time were you could cut them then yes they will fail .

 

[Damselfish]

zero to nill chance of blowing.now if you are in wrecks all the time were you could cut them then yes they will fail .

Why would you say "zero to nill chance" after examples given of them blowing? (I had one blow too, on the beach right when I opened the valve. !&^*&#^ rental gear!)

 

[midnite135]

I agree with Walter...

1# of gold and 1# of feathers are not the same weight.

Oh yea, and its Force VS Pressure in the ring this Sunday, Sunday, Sunday!

 

[midnite135]

Ack, I just realized I was still reading through my searched threads when I responded. Apologies for ressurecting the dead... no need to respond and we can watch it die again.

 

[letterboy]

NO it must live on like the exploding tank threads. . .

 

[MXGratefulDiver]

Gee Dr. K. Next time you dive, take your knife and cut your pressure gauge hose. You will find out that "it leaks very small bubbles". Not the whip of death you broadcast. :10:

Hmmm ... I had an SPG work itself loose from the hose on a stage bottle the other night. When I turned on the tank to do the switch, it emptied about 300-400 psi out of my AL40 in just the few seconds it took me to realize what was happening and turn the valve off.

It wasn't leaking very small bubbles ... it was gushing. At first, I thought my first stage had blown an o-ring or something.

... Bob (Grateful Diver)

 

[ChrisA]

you sure it was the high pressure? the HP is at tank pressure (around 3000psi) and not the low pressure (~150psi)

a hose with 150 psi with a good leak can whip around and hurt! (happend in the garage with my compressor) I would have to think that a 3000 psi hose could cut your leg or head off!

It is not as bad as you think. The inside diameter of an HP hose is very small and even if the hose is cust not all that much air comes out. I've seen this happen when my dive buddy jupped off a dive boat and his air intigrated computer was stuck on the boat's rail. The computer ripped loose. Lots of bubbles and noise but not a big deal. He just shut the valve and swam around to get back on the boat and find a replacement SPG.

 

[Mr Carcharodon]

We are on page 5 and no one has answered the original question if a hose failure is preventable by maintenance.

My guess is that typical maintenance would not prevent a hose failure in most cases. If fact typical maintenance for hoses is a quick visual inspection to see if they look “bad”. That is pretty subjective and certainly tells nothing about the inside of the hose which is probably what really where the failures start. The regulator manufactures provide recommendations for the maintenance of their parts but hose do not seem to be considered part of the regulator. Or at least I have never seen it covered in a regulator service manual. Hoses, and to a lesser extent yoke and DIN fittings, seem to be a no man’s land where no one specifies maintenance steps or a replacement interval. At least failures do not seem to be very common.

 

[oly5050user]

If you have a high-pressure hose blow underwater, it will sound like a billion screaming teapots. And, if that hose gets pushed up against your flesh, it can (will) force air under the skin, possibly causing death. A LP hose can do this too.

no way...if and when a hp hose goes and you are uw you probably would not even notice it untill you look for your spg..Happened to me during a training dive.I continued the skill portion and tour with the student and then took another one to do their skill and tour portion.My console blew off the of the hp hose fitting,no big deal..happen above water it leaks and the volume of gas is so small that the hose does not whip around at all.Takes long long time to drain out a tank that way.