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

[CuzzA]

That disc plug actually had 4 holes.

 

[John C. Ratliff]

That disc actually had 4 holes.
View attachment 377694

Interesting. Thanks.

Okay everyone, we just learned something. Even with opposing holes, these tanks will move during a Overpressure disc blowout. Maybe CussA's idea of tying these critters down is not a bad one. We used to place these tanks into a barrel of water during filling. Now, they are filled in place in a vertical position. It seems that there is some vulnerability to this filling procedure.

In an industrial setting, high pressure cylinders are not left standing without restraints.

Http://osha.oregon.gov/oshapubs/factsheets/fs09.pdf

SeaRat

 

[andrewy]

it happens. it is scary and loud. however much nicer to be on top when it happens. this is a reason cavers double up disks. Also important to have proper rating diskas and replace them now and then .. which reminds me

 

[John C. Ratliff]

it happens. it is scary and loud. however much nicer to be on top when it happens. this is a reason cavers double up disks. Also important to have proper rating diskas and replace them now and then .. which reminds me

Some cave divers seek to abrogate the safety factors of an Overpressure relief valve in the mistaken (in my mind) belief that there is a real possibility of this valve releasing underwater inside a cave. But what they really are doing is setting these cylinders up to become bombs in the event of a car fire. These Overpressure relief valves are designed to safely release the pressure inside a high pressure cylinder during a fire which engulfs the cylinder before the cylinder would rupture. This is why the older overpressure relief valves had cores of lead; they would melt and release the gas in a fire. Should there be a vehicular fire, and a tampered cylinder exploded, the vehicle operator may be liable for both fines and damages, as transporting altered cylinders across state lines is (I believe) illegal.

SeaRat

 

[KevinNM]

IIRC, Burst disks are a US/Canada thing, and I don't hear many stories about the hundreds of European divers killed by exploding tanks.

 

[CuzzA]

Interesting. Thanks.

Okay everyone, we just learned something. Even with opposing holes, these tanks will move during a Overpressure disc blowout. Maybe CussA's idea of tying these critters down is not a bad one. We used to place these tanks into a barrel of water during filling. Now, they are filled in place in a vertical position. It seems that there is some vulnerability to this filling procedure.

In an industrial setting, high pressure cylinders are not left standing without restraints.

Http://osha.oregon.gov/oshapubs/factsheets/fs09.pdf

SeaRat

SeaRat,

Having now seen this with my own eyes I think securing the tank during filling is a good idea. I don't think it has to be anything elaborate. Just something to keep them upright.

In my case since the valve knob took the brunt of the force when it landed I could imagine there was a possibility the valve could have broke, o ring extruded, or worse the nipple/threads of the tank could have cracked maybe even sending the valve and tank off in opposite directions as projectiles or in the latter outcome the tank could actually explode if there was actually damage to the integrity of the tank from an impact.

I'm only speculating on those scenarios and it would probably be a one in a million chance that happens during a burst disc failure, but nevertheless, aside from the human safety factor it also eliminates further damage to someones tank. Something simple like a pelican rack or roll control brackets would likely keep the tank in place.

Surely I'm not the first one to experience a disc failure during filling so I'd be curious to hear accounts from others who have.

 

[andrewy]

Some cave divers seek to abrogate the safety factors of an Overpressure relief valve in the mistaken (in my mind) belief that there is a real possibility of this valve releasing underwater inside a cave. But what they really are doing is setting these cylinders up to become bombs in the event of a car fire. These Overpressure relief valves are designed to safely release the pressure inside a high pressure cylinder during a fire which engulfs the cylinder before the cylinder would rupture. This is why the older overpressure relief valves had cores of lead; they would melt and release the gas in a fire. Should there be a vehicular fire, and a tampered cylinder exploded, the vehicle operator may be liable for both fines and damages, as transporting altered cylinders across state lines is (I believe) illegal.

SeaRat

John dont disagree, thats why GUE divers dont smoke seriously though steel tanks will rapture not explode. aluminium tanks will go KABOOM and if you have 100 or 50 % deco bottles in a car they will make the whole new show, proper burst disks or not. 100% O2 will burn anything.

 

[Doby45]

John dont disagree, thats why GUE divers dont smoke seriously though steel tanks will rapture not explode. aluminium tanks will go KABOOM and if you have 100 or 50 % deco bottles in a car they will make the whole new show, proper burst disks or not. 100% O2 will burn anything.

Must be the reason we are seeing fewer and fewer steel tanks.

 

[Bob DBF]

All of the sudden after about 30 seconds I got a gut feeling that he should not be anywhere near tanks when they're being filled.

I get that feeling anytime my kid, or anyone else's, gets near anything dangerous. You never know what a kid will do, and you never know if someone will screw up when handling dangerous equipment around a kid (who has no idea of watching out for his own safety).

Good call

Bob

 

[kelemvor]

In Florida the 3 shops I've looked at in any detail all are set up so the customer can get their tanks filled in their vehicles, and it's often 2 sets of 130 doubles that they are filling.

I've certainly seen that in the cave country region. In my area (Tampa Bay) all the shops have buckets or bins and the tanks get strapped in. The tanks are vertical and the bungee straps are mainly to keep tanks with round bottoms upright in the bin. I've no ide if the bungees are strong enough to keep a tank from flying away as was seen here.

Certainly shakes my confidence in burst disks. I was under the impression they allowed "safe" release of gas. I wouldn't call a tank flying around the shop "safe".

I would expect the shop to replace the valve since they damaged it when in their care. Maybe not a blown disk if that was all that had happened, but it wasn't. Honestly I'm surprised they didn't volunteer to replace the valve that was damaged while in their care. If my car blew up while the mechanic was working on it, I'd expect the shop to replace the car...