O-Ring Rupture while Underwater?

[EricPuryear]

I've seen a couple threads where people mention their tank valve O-ring rupturing at depth. I asked at my LDS and around Haigh Quarry in IL, but nobody has experienced this themselves, and most hadn't heard of that.

So has anyone here had an O-ring rupture while underwater? If so, what exactly happens? Do you lose all your air in a matter of seconds, or is there enough time for a safe ascent? Can you hear it, or do you notice when your tank is empty? Does the escaping air affect move you around considerably? How does this affect your regulator?

Thanks

 

[liberato]

Unless you try to remove the yoke while pressurized I can't visualize how you can blow a captive O-ring. Can this really happen if the yoke is properly attached?

 

[Web Monkey]

Unless you try to remove the yoke while pressurized I can't visualize how you can blow a captive O-ring. Can this really happen if the yoke is properly attached?

I've heard of it, but have never heard of it from anybody who has personally seen it, and can't quite picture it either, unless the yoke isn't attached properly or the o-ring groove is damaged or the o-ring is the wrong size or damaged.

There just doesn't seem to be enough space for an undamaged o-ring to get through the space between the ring on the yoke and and groove on the tank.

Terry

 

[MEL-DC Diver]

Happened to me 3 weeks ago - thankfully, before I submerged. Rental tank. I replaced the o-ring, crossed my fingers, and stayed VERY close to my buddy on that dive.

 

[rainman_02]

I was on a dive boat a few weeks ago and someone's o-ring ruptured. It was on the boat, after the dive, and she started to remove the yoke before depressurizing.

*POP!*

 

[JeffG]

Seen it a couple of times when a tank/regs are pressurized for the first time (which should be above the water), never seen it happen underwater. The only possible way I could see it happening is if a yoke adapter was hit/dislodged by something.

 

[humanFish]

I’ve seen a couple threads where people mention their tank valve O-ring rupturing at depth. I asked at my LDS and around Haigh Quarry in IL, but nobody has experienced this themselves, and most hadn’t heard of that…

So has anyone here had an O-ring rupture while underwater? If so, what exactly happens? Do you lose all your air in a matter of seconds, or is there enough time for a safe ascent? Can you hear it, or do you notice when your tank is empty? Does the escaping air affect move you around considerably? How does this affect your regulator?

Thanks

Ruptured O-Rings at depth can happen. The first stage can twist a bit in place and disturb/damage the O-ring, although this may not be the only reason for failure. This is one of the reasons people like DIN valves. Always check your O-Ring for damage and abrasion before seating the first stage. If it looks chewed up, then you'll want to replace it. Keep a few handy for this purpose.

 

[Chad Carney]

O-ring extrusion usually happens at the surface where the pressure is highest due to heat, and upon turning on a fresh tank, but it doesn't always.

I have seen yoke o-rings blow many times long after assembly on the surface, and a couple times while shortly underwater. The air loss is massive, but the diver was still able to breathe and make a quick ascent. Yoke face o-rings are not truly captured, like DIN valve o-rings, which are captured to the back of the valve. Yoke o-rings are usually thinner, more delicate and often neglected. (The Challenger accident involved poor o-ring design and heat.)

I witnessed only one diver have a DIN oring extrude, and it was at about 20' down. He had previous trouble getting the DIN fitting tight due to salt build up and an over-chromed DIN wheel. He could still breathe on his ascent.

I recall a buddy diving a DIN that hissed somewhat on a whole dive... later we discovered he never had an o-ring, just tightened it brass to brass real tight, and it worked!

Chad

 

[chrispete]

As far as the tank emptying in a matter of seconds, no. The orifice in the valve will keep that from happening. I'm sure one of the engineering types here would know how to calculate exact numbers on it, but I digress.

In any case, it will be likely that a) your regs will continue to function while the tank is draining, and b) you should be close enough to your buddy to get to alternate air if the reg were to go kaput with no warning whatsoever, so a failure with air still being supplied should be able to be dealt with.

 

[liberato]

Ruptured O-Rings at depth can happen. The first stage can twist a bit in place and disturb/damage the O-ring, although this may not be the only reason for failure.

I see. To me, then, this is the only serious danger: impacting or twisting the connection. The other incidents were due to defective and ill-maintained rental equipment and user error.