Low pressure hose failure

[deepstops]

Turning my valve on/off is one of my weekly drills and I don't find it arduous at all. But that was with a free flow in mind. With 83 seconds or whatever it takes for the tank to empty on an LP failure, I wasn't sure whether this kind of action would make much difference.

That's good, it an important consideration and a useful skill, even for single tank recreational divers.

Any 'inconveniences' to expect with folding over the hose? Like the hose exploding etc.?

And excuse my ignorance, but on a technical level, what is the difference with a HP hose jamming on and a 'failure' of this kind that will empty a tank so quickly? Is jamming on more likely sand etc. where this kind of failure is structural. Sorry if I'm asking dumb questions, but it's the only way I learn.

J

The original poster's failure COULD have been caused by a HP seat problem that allowed the IP (normally 125-145 psi depending on the reg) to go way too high and blew the hose apart but it's more likely the hose had a defect when it was made (as has already been stated). I'd still check my first stage IP to rule it out.

Folding the hose over is a viable option and won't cause any other failure provided the IP isn't running away.

 

[Salmonboy97]

Glad to hear everything worked out OK in the end. Thanks for a very useful post!

 

[ShakaZulu]

Wow, thanks for letting us know about this...one more thing to add to my checklist. I think diving is more dangerous than flying

 

[TSandM]

Kudos to your buddy, for being there, and being competent, and for you for keeping your head in a real OOA scenario.

We should all be prepared for such things. They are rare, but they do happen.

 

[49thdiver]

Good point, I have since replaced the reg, done an imtermediate pressure test, and even gone for a dive with the same first stage. It all worked flawlessly. Not to say that it did not stick but it is not now, I wonder would the 2nd stage free flow under such a high pressure situation like a stuck open first stage. I woul dlike to think so, but perhaps not.

Anyone know ?

The original poster's failure COULD have been caused by a HP seat problem that allowed the IP (normally 125-145 psi depending on the reg) to go way too high and blew the hose apart but it's more likely the hose had a defect when it was made (as has already been stated). I'd still check my first stage IP to rule it out.
.

 

[49thdiver]

I think diving is more dangerous than flying

Eh I don't think so, if I had a comparable failure to this at 1000ft above water, I don't think I would be making anyposts today. But I don't fly accept underwater, so what do I know.

Cheers

 

[wreckchick]

IMO, the 2nd stages would start leaking way before a hose would blow apart due to high IP.

Rachel

 

[Texfrazer]

IMO, the 2nd stages would start leaking way before a hose would blow apart due to high IP.

Acutally, the low pressure hose can fail before any noticable 2nd stages leak.

That's what happened to me when (a long time ago in a galaxy far, far away) I was just learning to work on regs and I mistakenly hooked a low pressure line up to an old parkway first stage high pressure port by mistake.

As I opened the valve, I had just noticed a very slight leak when BLAM, I've got a low pressure hose whipping back and forth after having failed and blown apart in the middle. I felt really dumb (and the guy teaching me was rolling on the floor with laughter).

Anyway, I had way less than a second before the hose blew, thus there was not enough time to recognize what was wrong.

However, if there was just a little creep occurring that slowly raised the pressure, then I would also agree that the 2nd stages should leak first.

Best to you, Peter, for not bolting to the surface and for having a good dive buddy!

 

[Rick Murchison]

IMO, the 2nd stages would start leaking way before a hose would blow apart due to high IP.

Change "would" to "should" and you've got it just right.

Rick

 

[wreckchick]

Change "would" to "should" and you've got it just right.

Rick

Thanks, Uncle Ricky

R