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haumana ronin
May 1st, 2011, 07:52 PM
If my BCD inflator were to get stuck open, how much time to I have to disconnect/vent before it could lead to injury?

I know there are a few different factors such as depth, starting position, and how open the inflator got stuck, so what are the different scenarios that you have actually seen?:shocked2: I wouldn't think that feet down at the safety stop is a good place to be when your inflator decides open fully. Has anyone been able to stop from this depth? What is the shallowest that anyone has stopped a runaway BC incident? Has anyone had to go to their knife?:eyebrow: Would you even have time to?

What is your ascent rate with a BC fully inflating? How much does flaring reduce your ascent speed? Obviously, I don't want to test this on myself just for the heck of it.:no:

I think starting at a good depth and kicking down with a small or medium lift BC could give you some time to disconnect/vent, although, kicking down does put the BC inlet near the lowest point, so I am not sure what is best.:confused:

Is there a way to practice this besides just disconnecting and reconnecting at depth? :dontknow: Seems like this might actually lead to the aforementioned ascent, but I don't know. Would quick piking practice help at all?

I have seen the other thread with the Hat, so don't post that.:tongue2: And yes, proper BC maintenance and not holding your breath on the way up are two important things too...

:zen:

Brendon
May 1st, 2011, 08:03 PM
I would not recommend diving with a bcd as you have described. However if it happened on a dive I would disconnect it as soon as you notice it and dump air until you are neutral. At your skill level, abort the dive. How long it would take to become dangerous or lead to injury is irrelevant. There are to many variables to consider, giving out some kind of time frame before an injury would result is not worth the time spent figuring it out.

evad
May 1st, 2011, 08:18 PM
[QUOTE=haumana ronin;5870213]
Is there a way to practice this besides just disconnecting and reconnecting at depth? QUOTE]




Yes, practice it in your kitchen (without looking at it.)

fisheater
May 1st, 2011, 08:20 PM
Inflators are designed to dump faster than they inflate. So, if you dump while futzing with the hose, you have as much time as you have air. :-)


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Jax
May 1st, 2011, 08:23 PM
Inflators are designed to dump faster than they inflate. So, if you dump while futzing with the hose, you have as much time as you have air. :-)


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Practice the sequence without looking - Inflator sticks, hit exhaust button, disconnect hose. 1-2-3 Practice until it comes flawlessly without fumbling.

spectrum
May 1st, 2011, 08:25 PM
The dump valves on most BCs are designed to vent faster than the inflater can fill. That means that if you notice the valve is stuck the first thing you can do is dump air to control the situation for the instant.

Once you are into the situation disconnect the inflater hose. Many BC have a tug dump valve integral to the inflater assembly. With these you can keep tension on the inflater hose while you break the connection. Practicing this skill from time to time is your best insurance.

In all cases you need to keep the situation under control so you are venting from the highest point.

Pete

g1138
May 1st, 2011, 08:52 PM
Inflators are designed to dump faster than they inflate. So, if you dump while futzing with the hose, you have as much time as you have air. :-)


Sent from my iPhone using Tapatalk

Not if you have an Air 2. Those things inflate crazy fast compared to traditional inflators. I'd call the ratio about even.


To the OP
Here at my school we practice BC disconnects and emergency flares for such an event. For the latter we have all our students lie 13ft on the pool bottom facing up. Once they give us an OK, DM's and instructors then mash down on the students inflator until their BC auto-dumps, then we let go. We usually have to hold them down for a few seconds before this happens. For me this is fairly easy to do.
With an Air 2 it happens a lot quicker, I only have to hold the student for a brief second before I can let them go.

In reality the higher you rise the harder it'll be to kick down as your BC continues to inflate and the air expands. If you have ever swam from the bottom with 10lbs of extra weight, imagine that but 3 times harder when you're trying to swim down with a full BC.

You should be aware enough of your situation to hear or feel your BC inflating, even if you're not the one doing it. (hearing it is generally easier than feeling it IMO)

If I hear my BC start to auto-inflate I would immediately do a Dump-Tap-Dump. That is dump my air and tap hard on the inflator button, then dump again to keep me from rising. If the inflator still auto inflates I'd then go for the inflator hose and disconnect it. You then end your dive safely. If you're comfortable orally inflating to keep neutrally buoyant then do so for your safety stop. Otherwise skip it and ascend safely to the surface, end of dive.

On the other hand if I find myself beginning to rise before I realize I have a runaway inflator, then I'd disconnect my hose THEN dump my air, or I'd flare out if I were already rising too fast. I chose to do it this way instead of the reverse because I feel I can disconnect my BC hose quickly and I'd rather nip the problem in the bud first.

Generally speaking, lots of our students have a hard time disconnecting their hose (not sure if it's them or the rentals, they're a bit stiffer than normal but I've never had a problem). They have an even harder time putting it back on.

A good technique I found is to:
1) grip underneath your inflator with your right hand, so the inflator is pointed up and your hand is wrapped around both hoses.
2) Death grip it and invert your left hand over the top of the inflator.
3) Push down on the collar with your left fingers and the air pressure should pop your hose off for you. (you may need to push your inflator hose up into the inflator sometimes)

Putting it back on is trickier:
1) First I would feed a little bit of hose off the BC hose clip (if you have one). Hold the inflator up with your left hand.
2) Next with your right hand, move your inflator hose collar down and push it up onto the inflator, but not hard enough to send air spraying out of the hose.
3) Finally grasp the hose below the collar and push up until you hear air leaking from the collar, at this point slide your index finger and thumb up to assist the collar in locking onto the inflator.
4) All the while our thumb's "palm" and other three fingers should be locked around the hose and pushing up, while our left hand is pushing the inflator down onto the hose.

Give is shot in the garage with your gloves on :D

dumpsterDiver
May 1st, 2011, 09:09 PM
If an inflator started to automatically inflate, I would disconnect ASAP while dumping air. An AIR II inflator may inflate faster, but it is also about 10 times easier to disconnect in a hurry.

For me, if an inlfator was sticking and inflating the BC (more than a trickle) I would probably complete the dive without using it. Why risk hooking it back up? Not having a power inflator on a BC should not be that big of a deal to cause you to abort the dive, unless it makes you uncomfortable.

evad
May 1st, 2011, 09:20 PM
Practice until it comes flawlessly without fumbling.


Nothing "comes flawlessly without fumbling."

Frosty
May 1st, 2011, 09:38 PM
Of course theres the odvious question. Why would an inflator fault?
When you look at them they aren't exactly complicated bits of kit.
So either you've got hooked up in weed/line/mud thats jammed it up or you are diving with a really well worn inflator.
How would I deal with it? disconnect the inflator hose most likely then figure out what was jamming up the button.
Happy to be shot down in flames here

evad
May 1st, 2011, 09:44 PM
I don'tcha.

Frosty
May 1st, 2011, 09:48 PM
Well thanks for that bit of clarification. I can rest easy tonight.
Ya do know sarcasm is the lowest form of wit doncha?

CamG
May 1st, 2011, 11:28 PM
Greetings haumana on the topic of stuck open inflator it is possible to control your buoyancy with in a reasonable range of depth.
It is usually easy to catch the leak immediately as you hear the air leaking at first simply detach the hose.
When this has happened in the several times I have witnessed no one lost control of their buoyancy into a run away ascent.
In one training dive that it took place I swapped BC's with the student and orally inflated to finish the dive.

It is really not a big deal but it is important to be able to disconnect the inflater in a timely manor.
I would be very careful and not recommend taking a knife to your BC or inflator,
As others have mentioned the dump is designed to release more air than the inflator will allow in so arresting a ascent is not impossible and really pretty easy IF YOU REMAIN CALM!
Obviously your dive will be aborted and you will begin your ascent in a safe manor.
It is not a bad idea to practice detaching your inflator and orally inflating in a pool to keep the skills sharp.
I would not recommend practicing this at deep depths there is no reason to take those chances but do so in a safe manor in OW.
Training platforms at 20' would be where I would move to after the pool training!

The thought process you are developing is a good one preparing yourself for failures, the "What If's" but you must be very careful training for these.
You do not want a training scene to become a full blown emergency.
You can practice skills anywhere but always start above the water and gain familiarity with your gear.
Be responsible with gear care and preparation, diligence pays off.

Safe training,
CamG Keep Diving....Keep Training....Keep Learning!

dumpsterDiver
May 2nd, 2011, 12:25 AM
Of course theres the odvious question. Why would an inflator fault?
When you look at them they aren't exactly complicated bits of kit.
So either you've got hooked up in weed/line/mud thats jammed it up or you are diving with a really well worn inflator.
How would I deal with it? disconnect the inflator hose most likely then figure out what was jamming up the button.
Happy to be shot down in flames here

It is a relatively common scuba failure, based on my own observations, it is the most likely failure after a regulator free-flow and maybe regulator mouth pieces falling off.

An uncontrolled inflation is an emergency, possibly more dangerous than a freeflow and it was one of the reasoans that when they were first introduced, power inflators were recommended only for experieced divers due to the perceived danger of this problem..

It is a relatively common failure that could easily cause death if handled wrong. It is an important question. I have been very disappointed when I ask new certified divers what they would do if the inflator stated filling the bc by itself and they just giiggle nervously, because they have no clue and are completely unprepared for it.

I used to like the old style of inflator, Dacor and many others used, if the inflate button got stuck, you could easily grab it, pull it back out, spin it a little and the problem was resolved immediately.

TraceMalin
May 2nd, 2011, 01:09 AM
If you invert you should be able to kick down against a fully inflated BC which will give you all the time that your muscles can give you.

I demonstrate this in classes for the students while wearing 40lb. and 60lb. lift wings. But, you'll need a good strong kick. I use the flutter kick.

If you feel yourself begin to rise and exhaled gas from your lungs and dumping from the BC or wing doesn't work, immediately invert and begin kicking with all you've got. Locate your rear or some lower dump valve on your BC which will now be the highest dump since you are inverted and begin dumping gas as you swim down. That should give you time to pop the Schrader valve on your LP inflater hose.

If the valve is stuck, there are several other actions one can take, but they require truly expert diving skill and I don't want to specifically describe these actions here. They involve shutting off gas or removing valves.

These emergencies should never be practiced on one's own without an instructor who is proficient in the skills. Most, but not all, tech instructors should be able to safely teach and lifeguard you during practice.

Scott L
May 2nd, 2011, 01:11 AM
TM, interesting. :thumb:

Frosty
May 2nd, 2011, 01:50 AM
It is a relatively common scuba failure, based on my own observations, it is the most likely failure after a regulator free-flow and maybe regulator mouth pieces falling off.

An uncontrolled inflation is an emergency, possibly more dangerous than a freeflow and it was one of the reasoans that when they were first introduced, power inflators were recommended only for experieced divers due to the perceived danger of this problem..

It is a relatively common failure that could easily cause death if handled wrong. It is an important question. I have been very disappointed when I ask new certified divers what they would do if the inflator stated filling the bc by itself and they just giiggle nervously, because they have no clue and are completely unprepared for it.

I used to like the old style of inflator, Dacor and many others used, if the inflate button got stuck, you could easily grab it, pull it back out, spin it a little and the problem was resolved immediately.
Hey thanks for that. (no sarcasm meant at all) But all that said I just cant see the mechanical reason for a simple valve to fail.
If it is as common as you say then what causes that kind of failure and what should be done to prevent it?

dumpsterDiver
May 2nd, 2011, 01:35 PM
Normal maintenance should make it unlikely, but I have seen it happen many times.

For myself, I think I have only had it happen 4-5 times, but these incidents were slow trickles that I couldn't even hear, I would have to vent the BC every 5 minutes and after the third time, maybe I begin to suspect a problem. Don't recall ever having an inflation emergency myself.

TSandM
May 2nd, 2011, 01:56 PM
Like every other moving part underwater, inflator valves are subject to corrosion and salt crystal formation, and the o-rings age and fatigue. I have serviced our inflators many times because of slow inflation leaks -- these are manageable. The old Halcyon stainless inflators were prone to a much more serious leak, which caused at least one injury of which I am aware.

But probably one of the biggest causes of massive inflator leak would be 1st stage freezeup, with the ensuing excess intermediate pressure venting through the inflator. This would be a very rapid and dangerous leak.

Frosty
May 2nd, 2011, 04:38 PM
Normal maintenance should make it unlikely, but I have seen it happen many times.

For myself, I think I have only had it happen 4-5 times, but these incidents were slow trickles that I couldn't even hear, I would have to vent the BC every 5 minutes and after the third time, maybe I begin to suspect a problem. Don't recall ever having an inflation emergency myself.

Now that makes sense-general wear n tear causing a slow leak--Kinda like a worn tap washer.Of the failures you have seen how many were of this nature and how many were emergencies?



Like every other moving part underwater, inflator valves are subject to corrosion and salt crystal formation, and the o-rings age and fatigue. I have serviced our inflators many times because of slow inflation leaks -- these are manageable. The old Halcyon stainless inflators were prone to a much more serious leak, which caused at least one injury of which I am aware.

But probably one of the biggest causes of massive inflator leak would be 1st stage freezeup, with the ensuing excess intermediate pressure venting through the inflator. This would be a very rapid and dangerous leak.
Wouldn't first stage freezeup cause the oposite effect.Ie no air? or your second stage to suddenly freeflow?
The danger refered to is a sudden return to the surface but don't all BC's have an emergency dump to prevent overinflation? so it can only fill to max.

Doesn't propper washing of your gear prevent crystal formation?
Doesn't regular maintainence prevent the o ring failure?

Hey again guys please this isn't some "smartalec kid" trying to prove you guys wrong or anything idiotic like that This is a genuine desire to understand.

dumpsterDiver
May 2nd, 2011, 05:35 PM
Now that makes sense-general wear n tear causing a slow leak--Kinda like a worn tap washer.Of the failures you have seen how many were of this nature and how many were emergencies?



Wouldn't first stage freezeup cause the oposite effect.Ie no air? or your second stage to suddenly freeflow?
The danger refered to is a sudden return to the surface but don't all BC's have an emergency dump to prevent overinflation? so it can only fill to max.

Doesn't propper washing of your gear prevent crystal formation?
Doesn't regular maintainence prevent the o ring failure?
Hey again guys please this isn't some "smartalec kid" trying to prove you guys wrong or anything idiotic like that This is a genuine desire to understand.

NO NO NO. Regular maintenance REDUCES but never prevents gear failures. You need to move away from the idea of "prevention" and more toward "trying to make it less likely that stuff fails".

Put a brand new hose on your regulator... It is probably more likely to blow on the first dive than a one year old hose that has done 100 dives...

Saudi-Diver
May 2nd, 2011, 05:58 PM
Dumpster Diver has very eloquently summed up every equipment failure I have ever had. The spectacular failures have all been with recently serviced or new equipment. Usually you get loads of warning of an issue, a reg starts to Free flow a little in current or an inflator starts to sneakily inflate your BCD. Familiarity with your equipment is a good thing. Also if it feels wrong but you cannot put your finger on whats wrong trust your instincts, its wrong.

Frosty
May 2nd, 2011, 06:58 PM
well thar you go -I learned something today. Thanks guys

haumana ronin
May 2nd, 2011, 09:44 PM
If my BCD inflator were to get stuck open, how much time to I have to disconnect/vent before it could lead to injury?

**cut**

What is your ascent rate with a BC fully inflating? How much does flaring reduce your ascent speed? Obviously, I don't want to test this on myself just for the heck of it.:no:




To the OP
Here at my school we practice BC disconnects and emergency flares for such an event. For the latter we have all our students lie 13ft on the pool bottom facing up. Once they give us an OK, DM's and instructors then mash down on the students inflator until their BC auto-dumps, then we let go. We usually have to hold them down for a few seconds before this happens. For me this is fairly easy to do.
With an Air 2 it happens a lot quicker, I only have to hold the student for a brief second before I can let them go.

Sounds like a neat exercise. How fast were they rising with a full BC? Do all of them successfully disconnect? What about lung over expansion for new student divers who might be holding their breath in the excitement of it all?

************************************************
OK, so practice on land, then in the shallows, then with a prewarned buddy or instructor in the deep. Practice until it becomes easy without looking. Part of my original question remains though: how fast? Tenth, quarter, half, one, or how many seconds? I did it in OW, though at chest level, but there was never a target time and I was futzing with it a while.

And stabilize depth either by venting while finning down and by venting while disconnecting the power inflator. At all times keep venting to maintain depth, which is easy since dump valves are faster than inflators. A dump-fill-dump might be enough to work the valve shut if it is not a rapid emergency. OK

And truthfully, if it happened and I caught it soon enough, I would probably leave it disconnected and continue the dive.:cool2: After inflating to level out my initial descent and venting a couple times during the dive, the BCD just seems like a handy place to hang weight pouches....

:zen:

windapp
May 2nd, 2011, 10:12 PM
If it is as common as you say then what causes that kind of failure and what should be done to prevent it?

Any valve that is pushed back by a spring or air-return can fail when the friction of the valve exceeds the force of the spring. This is usually caused by contamination like sand or silt. I had air-pilot return valves fail on my in a manufacturing situation when the synthetic compressor oil over-expanded the buna rubber o-rings. Of course, if this happenes in your scuba equipment, your air is really really bad.


Wouldn't first stage freezeup cause the oposite effect.Ie no air? or your second stage to suddenly freeflow?


A regulator (in its simplest form) is essentially a valve that has a preloaded spring pushing it open against air pressure coming from the downstream flow. If the valve froze, it could freeze in any position, open or closed, or somewhere in between.

TSandM
May 3rd, 2011, 12:30 AM
When my buddy and I did our first dive with Andrew Georgitsis, we got about five feet underwater when Andrew grabbed my buddy's inflator and mashed on it. He went head down, kicked down, and opened his butt dump. He was able to remain underwater until I was able to help him with a more permanent solution to the problem (and no, it was not removing Andrew :) ). So, if you respond promptly to an autoinflating BC, you probably have a lot of time to solve the problem. If you do not recognize what the issue IS, not so much.

You are correct that a BC can only inflate to the pressure that pops the OPV -- but that's a tremendous amount more air than you need, even at deep depths, so a full BC is going to be a powerful force to lift you to the surface.

Freezing in a first stage may cause the piston not to seat smoothly, which means the first stage will continue to allow high pressure gas out of the tank, even when the second stage valve is closed. That excess pressure will blow out somewhere . . . usually as a freeflow, but on occasion, it may blow through the BC or drysuit inflator.

vladimir
May 3rd, 2011, 12:58 AM
I have seen the other thread with the Hat, so don't post that.:tongue2: And yes, proper BC maintenance and not holding your breath on the way up are two important things too...

:zen:You've seen the hat, but have you seen Deep Sea Supply's valve flusher (https://www.deepseasupply.com/index.php?product=1301)? It looks like a good idea to me, and I would have one if I had a garden hose. They also make a handy little tool for disassembling inflators (https://www.deepseasupply.com/index.php?product=1302), which I do have, and which works well.

BluewaterSail
May 3rd, 2011, 01:02 AM
This thread is timely for me, as I have been mulling it over in my mind.

This past Friday, the night dive from my AOW was ended early because this happened to another participant. The diver had an unusual Aqualung bcd, which has a lever mounted on bcd itself to inflate, rather than a button on a hose. Her computer somehow got wedged in, and the lever was jammed to the open position. Having accidentally dropped her flashlight while trying to unjam the lever, she had no option but to surface and swim back to the shore. With the rest of us following once we figured out what happened.

Ever since that, I have been going over scenarios in my mind.

Also, as I observed in my offshore sailing in the past, its usually not one thing going wrong that gets you, its that it starts a series of unfortunate events that further complicate the situation.

dumpsterDiver
May 3rd, 2011, 08:45 AM
.

Also, as I observed in my offshore sailing in the past, its usually not one thing going wrong that gets you, its that it starts a series of unfortunate events that further complicate the situation.

Definitely true in diving as well.

Frosty
May 3rd, 2011, 03:57 PM
Definitely true in diving as well.
It applies in other "worlds" too. =The day you forget your dive knife is gonna be the day you need it.

CoolTech
May 3rd, 2011, 04:20 PM
If my BCD inflator were to get stuck open, how much time to I have to disconnect/vent before it could lead to injury?

I know there are a few different factors such as depth, starting position, and how open the inflator got stuck, so what are the different scenarios that you have actually seen?:shocked2: I wouldn't think that feet down at the safety stop is a good place to be when your inflator decides open fully. Has anyone been able to stop from this depth? What is the shallowest that anyone has stopped a runaway BC incident? Has anyone had to go to their knife?:eyebrow: Would you even have time to?

What is your ascent rate with a BC fully inflating? How much does flaring reduce your ascent speed? Obviously, I don't want to test this on myself just for the heck of it.:no:

I think starting at a good depth and kicking down with a small or medium lift BC could give you some time to disconnect/vent, although, kicking down does put the BC inlet near the lowest point, so I am not sure what is best.:confused:

Is there a way to practice this besides just disconnecting and reconnecting at depth? :dontknow: Seems like this might actually lead to the aforementioned ascent, but I don't know. Would quick piking practice help at all?

I have seen the other thread with the Hat, so don't post that.:tongue2: And yes, proper BC maintenance and not holding your breath on the way up are two important things too...

:zen:4 ft.

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