Close Call at the LDS and a High Pressure Reminder...

[cerich]

This discussion of burst discs brings up a question some divers I know were discussing/arguing around the bar recently.
If a recreational Nitrox fill <=40% was to rupture a burst disc in the sun in a boat. How much of a hazard would that create in regards to fire on board? Bearing in mind oils, fuel and electrics etc.

it won't unless there is already one (fire) happening.

higher close to pure Oxygen % however during the burst disc event you have have a combustion event possibly. That would suck. If the combustion event happens in the valve, the rapid burn is very likely to be called an explosion

 

[CuzzA]

let me fix that for ya

You paid to have them O2 cleaned, if the valve as taken apart properly for a O2 clean, the disc would have been replaced.

You didn't get what you thought you got.

Really glad your child wasn't injured.

I have had burst discs go many times in my career, never saw a tank hit the ceiling I have however had the escaping gas do a good job of blowing the dust off, moving stuff off shelves etc. I would bet the ceiling tile was hit by air, not the tank. I could be wrong.

No, that would be silly for the tank to hit the ceiling tile. I stated it left the ground by about a foot as it flipped. The air escaping the burst disk was enough to blow out the ceiling tile 10 feet above it.

The point I was trying to make is either the tank flipping violently and/or the air escaping would be enough to possibly injure someone, especially a three year old child.

 

[cerich]

Perhaps you and @KDAD are reading a different thread or you both need to work on your reading comprehension skills as I never once said the tank was flying around the shop. The tank DID NOT just tip over. Had it tipped over it would have been impossible to damage the knob and valve stem. There was nothing else near it that it hit. The tank was off the ground sideways and landed on the knob. A failed flip is the best way I can describe it.

Apparently you two think compressed gas is no big deal, but I wonder if you have small children or are willing to put YOUR face next to a burst disc letting go. I recall a recent thread on here where either a valve o ring extruded or burst disc let go at night and the op was in his garage trying to find the source among tanks and consequently put his hand in front of the gas escaping and it basically tattooed air into his hand and under his skin.

that is not what he is saying, he is saying that the damage (other than your valve) was the gas escaping, and it is not as dangerous as it may appear to somebody who has never experienced a burst disc failure.

That said, there is real danger, hearing, gas could blow something into a eye, gas could get a eardrum etc. The falling tank is a very real danger as well, because it isn't just falling, it has energy beyond weight and gravity behind, especially to a toddler.
The shop (and parents) should NEVER let children around he tank fill station, in fact in many places it's illegal to have kids around them under 16. Florida has laws regards that BTW.

My 10 year old has a literal office in my building and likes to hang around here, but the warehouse and fill station are off bounds, and she knows it.

When a burst disc goes, move away and stay away until there is no sound of gas escaping. The tank filler (who is supposed to be there while filling the tank, not wandering around the shop) should immediately shut down filling and vent the panel..and move away. Not futz with the tank. You may think it is a burst disc, it could be something else and potentially go boom. Also as you pointed out, gas under 3000psi of pressure will not just tattoo skin, it can do some really bad cutting as well

 

[cerich]

No, that would be silly for the tank to hit the ceiling tile. I stated it left the ground by about a foot as it flipped. The air escaping the burst disk was enough to blow out the ceiling tile 10 feet above it.

The point I was trying to make is either the tank flipping violently and/or the air escaping would be enough to possibly injure someone, especially a three year old child.

agree

 

[cerich]

Rated 4000, intent to fill to 3500 which normally cools to about ~3200.

umm..what kind of tank did you intend to get filled to 3500 cool to 3200?
If a alm 3000 psi rated tank, stop.

they should be filled to 3200 max, cool to 2900-3000. I once hydro'd about 200 7 year old alm tanks that were in resort use, and got that 3500 fill treatment. Over half of them failed eddy testing and at least 15% the actual hydro.

It's a REALLY bad idea to fill alm 3000 psi tanks to 3500 psi. Frankly it's still rare to have a explosive issue, however it is MUCH more likely by a order of magnitude.

Given what happens when they do fail, it simply is absolutely not worth it

 

[CuzzA]

umm..what kind of tank did you intend to get filled to 3500 cool to 3200?
If a alm 3000 psi rated tank, stop.

they should be filled to 3200 max, cool to 2900-3000. I once hydro'd about 200 7 year old alm tanks that were in resort use, and got that 3500 fill treatment. Over half of them failed eddy testing and at least 15% the actual hydro.

It's a REALLY bad idea to fill alm 3000 psi tanks to 3500 psi. Frankly it's still rare to have a explosive issue, however it is MUCH more likely by a order of magnitude.

Given what happens when they do fail, it simply is absolutely not worth it

C'mon Chris, everyone knows I dive fat steels. Haha... LP108's to be exact.

 

[cerich]

C'mon Chris, everyone knows I dive fat steels. Haha... LP108's to be exact.

umm... here is here my experience and actions deviates from "best practices".

My steel get the same. That said, I don't do stuff like double disc or bolt the burst disc assembly. I properly overhaul valve and new burst disc every time.

 

[Caveeagle]

C'mon Chris, everyone knows I dive fat steels. Haha... LP108's to be exact.

I love my LP108s (OMS112).. Want another set...

 

[cerich]

I love my LP108s (OMS112).. Want another set...

I had three sets of them doubled and a set of 104's doubled..now I have two sidemount sets and divested myself of two sets of doubles. Yet mostly use my LP 85's SM now

 

[CuzzA]

umm... here is here my experience and actions deviates from "best practices".

My steel get the same. That said, I don't do stuff like double disc or bolt the burst disc assembly. I properly overhaul valve and new burst disc every time.

Indeed. It was clearly an oversight. From now on my valves will get new burst discs at hydro. In fact, all of my tanks were due for hydro over the winter so I took that opportunity to switch everything over to DIN so everything has new hardware including burst discs.

For any readers it's a good lesson in that if you're going to own your own gear, the buck stops with you to ensure you are knowledgeable enough to know what does and doesn't need to be addressed. Which goes for most things in life.