My Reg incident

[cjust]

I thought I'd share my recent reg incident, please take a look at this thread for the story. (note the specific LDS is not important, it is the events that I think we can all learn from)

Since I survived unharmed, I can say that was an amazing learning experience. I have a full predive checklist, but checking the tightness of my hose connections had never been on it. I wasn't taught that and I had no idea it was something I was expected to do. I have also since learned that it is possible to crimp the hose in such a situation to preserve air. Both my buddy and I tried to crimp it at the time, but I guess we weren't doing it quite right, because neither of us could get the air to stop.

I hope anybody that sees this (or the video in the original thread) will keep it in mind on future dives. I feel like I was able to remain pretty calm throughout the ordeal which helped the situation. However, since such an event had never even crossed my mind prior, things could have been much worse if I hadn't already switched to my backup at the time the hose came apart. As it happened, I was still able to breathe while I figured out what was going on and what I needed to do. Now I feel like I will be better prepared in case of a future emergency.

 

[undefined]

I'm signing up for an equipment specialist class in response to the original thread on this. You should feel quite good about how well you dealed with the situation - keeping a level head and getting help from your buddy kept this from being a more serious situation. Thanks for sharing your experience, and reminding the rest of us to double-double check our gear.

 

[TSandM]

One of the things I was taught in Fundies was to do a bubble check before every dive. It's quick -- You simply submerge all the source of compressed gas that you have, and have your buddy take a look and see if there are any leaks. Many times, a loose hose, or a failing O-ring will produce "champagne bubbles" at the beginning of the dive, and you can investigate and fix the problem and avoid a bigger issue at depth.

 

[ArcticDiver]

Not trying to beat on you; others will do that I'm sure. BUT a proper predive and entering the water protocol will help eliminate this kind of problem.

-When you hook up your regs check all the connections to be at least finger tight.
-Breathe through all your regs as soon as you connect them to their respective tanks. Check the pressure gauge as you do so.
-Immediately after entering the water do TS&Ms bubble check. I was introduced to this on my first wreck dive and have found it to be very useful.
-Breathe through your regs again immediately after entering the water.

Now there are circumstances where the mix or the enviromental conditions make breathing through all your regs on the surface or immediately after entering the water an unwise thing. In those case do the check before a malfunction would be a critical event.

Shop techs are human. They make mistakes. Expect them.

 

[RJP]

Shouln't this post be in Lessons Learned?

 

[redacted]

One of the things I was taught in Fundies was to do a bubble check before every dive. It's quick -- You simply submerge all the source of compressed gas that you have, and have your buddy take a look and see if there are any leaks. Many times, a loose hose, or a failing O-ring will produce "champagne bubbles" at the beginning of the dive, and you can investigate and fix the problem and avoid a bigger issue at depth.

The problem is that a loose connection between the hose and a 2nd stage is not going to leak initially. By the time it does start to leak, that connection is already half way off. In addition to a bubble check, you need to check that (and other screw in assemblies) by hand to make sure they are more secure than finger tight. Unless, of course, you intended to leave that connection only finger tight to enable swapping out of malfunctionaing 2nds during a dive.

 

[james croft]

It has been my experience that regs that fail often do so after being serviced. There are many reasons this happens but it is very important that you go over your equipment and bubble test it and check connections before diving it.

I learned this the hard way. I had a Conshelf 14 overhauled and did not check it. I was going to make a dive in relatively fast moving water in a river. I added additional weight to hold me to the bottom as I was conducting a search. I had not yet learned to do a vacuum test of my reg by trying to breath on it with the air cut off. I did test my reg with the air on and breathed from it. It breathed wonderfully and very quietly. Wow, I thought, they did a good job on the overhaul. This is the sweetest breathing reg I had used.
I was in about 8-10 feet of water and jumped in from a boulder we were using to work from. I had vented my air out of my horsecollar bc to allow me to sink quickly before the current carried me too far downstream. My first breath underwater was nothing but water and I began choking. Very short dive. There was no exhaust valve installed in the second stage. While the LDS screwed this up badly and it was inexcusable, I learned a valuable lesson. I began to learn how regs worked, how to work on them, got the manuals and now work on my own regs. It has made me a lot better diver and has saved many dives from being called due to minor problems.

My department issues me regulators and I must take them to be overhauled, but I always double check them before use. ALWAYS test your regs with the air off and if you can suck any air from the second stage, there is a leak somewhere. Fix it before diving it.

 

[TSandM]

I've had second stages come loose twice, both immediately after being serviced. I think when you get your regs back from being taken apart is a particularly important time to check all the connections.

Another point -- if you DO start having bubbles from a screw-in connection while you are diving, DON'T try to tighten the connection unless you depressurize it. Otherwise, the threads will slice the o-ring, and a small leak will become a big one in a hurry. (And obviously, if you are diving a single tank, the only way to depressurize the connection is turn your gas off, which is not a good idea unless you have good conditions and a well-trained buddy to air-share with while this is all going on. Much better to abort and make a controlled ascent.)

 

[redacted]

I've had second stages come loose twice, both immediately after being serviced. I think when you get your regs back from being taken apart is a particularly important time to check all the connections.

Another point -- if you DO start having bubbles from a screw-in connection while you are diving, DON'T try to tighten the connection unless you depressurize it. Otherwise, the threads will slice the o-ring, and a small leak will become a big one in a hurry. (And obviously, if you are diving a single tank, the only way to depressurize the connection is turn your gas off, which is not a good idea unless you have good conditions and a well-trained buddy to air-share with while this is all going on. Much better to abort and make a controlled ascent.)

I believe it would be OK to retighten a leaking 2nd stage hose connection without depressurizing. It is unlikely to cause any damage to the o-ring which will normally just stay in the groove where it is installed. Pressures there should not be high enough to cause the that o-ring to extrude. If that O-ring does partially dislodges from the groove it is sitting in then damage could occur, but the leak should be reduced or at least contained by snugging up the connection by hand. That is one of the o-rings most divers should have in their save-a-dive kit. If hand tightening does stop the leak, there should be no reason to abort the dive.

It is not like the hose connections at the 1st stage where a leak, especially HP, will frequenly involve extrusion of the o-ring.

Edit: My apology to TSand M. After a second claim on another thread that the o-ring would be cut, I gave it a try. I sliced it in two on the first try and decided a sample size of one is enough.

 

[ArcticDiver]

... ALWAYS test your regs with the air off and if you can suck any air from the second stage, there is a leak somewhere. Fix it before diving it.

Thanks for making this point. It is a part of my breathing test but I didn't call it out in my post.

Why just check for finger tight? Because my test is on the boat or shore before EVERY dive. Even if I just dove with the rig an hour ago I do all the tests again. In that circumstance finger tight is all a person can check.

Certainly every rig should be checked thoroughly right after servicing. But be very careful with tools and checking connections. Unless you are experienced it is all too easy to overtighten connections. I've seen some fairly dimunitive people overtighten connections to the point that within a short time after they were pressurized the connection failed.

About the bubble test: You are not checking for absence of bubbles in all cases. I dove with a guy whose rig gave off small bubbles the entire dive. According to him and the shop tech that particular brand/model of reg is supposed to give off bubbles. I don't remember which brand/model it was.