Double Your Burst Disk - Arguments For & Against, Please...

[wedivebc]

b. A steel tank has never exploded (don't DD alums) and good luck finding the valve after a tank does.
.

That is funny
Actually steel tanks exploding is not entirely uncommon. I am referring to the old 2250 psi tanks now but there was a picture circulating around of a car that had a tank explode inside while parked in the sun. I remember seeing an exploded steel tank on display at a dive shop. Might have been at Oceanquest in Vancouver. Toodles, you around?

 

[JS1scuba]

I don't really care for the practice. On all of my cylinders the burst disk is installed. I do make sure that the disk on the valve is the correct one for the cylinder in question. I carry spares for each type of cylinder with me in my save a dive kit. When the valve gets serviced (by a shop) I make a point of letting them know that I would be happy to have the disk replaced, and if that request means that I will need to pay a slight additional charge that I am willing to pay the cost.

I have seen one disk fail in person, it was in a shop while the cylinder was getting its first fill after an inspection. The cylinder was not mine, just coincidence that I was in the shop when the disk failed. Yes, they are really loud and it did scare the crap out of us.

I do not lay awake at night worrying if the disks on my cylinders will fail. I do not spend my entire dive worrying if the disk will fail. I am concerned for firefighters and other possible bystanders in the unexpected event of a fire. Firefighters have enough to worry about without my adding the risk of exploding diving cylinders to the mix. I also make a point of storing cylinders either full or nearly empty.

Mark Vlahos

Here Here -- way to go Mark,

I just counted how many cylinders I have in the shop that are full at the moment.
It's about 110 back there I am so glad we inspect cylinders on a regular basis. I can guarantee that if that place when on fire there would be 110 safteys all blowing off about the same time. Our fire department knows we have compressed gas cylinders here and they have visited us from time to time to inspect and check safteys. They even know i have cylinders in my house and where we keep them just so they know.

I like those guys.

Thanks Mark!

Cheers
JDS

 

[JS1scuba]

First of all for all of those using the law argument who cares about the law. Its illegal to overfill but that hasn't stopped that all the cave divers and everyone else who does it.
Secondly how often do tanks that are in Vis and hydro spontaneously explode when getting filled to a pressure that is something close to what it is rated to? Pretty much never.
Thirdly I HAVE seen burst disks hit in an overhead environment and go that way, but not just spontaneously.
Lastly if Europe isn't worried about thier firemen dieing from exploding tanks then I don't think we should be. I think the risk to you is much greater if you hit the disc on the back of your manifold against a cave ceiling then start losing all your gas and have to isolate and then exit a cave system than it is to a firefighter in this hypothetical fire.

Please go visit your local fire house and share this with them.

shaking head.......

 

[JS1scuba]

No. Typically officers pull over personal vehicles for speeding, some as part of drug interception, but scuba tanks, legal or illegal would not even cross the radar.

My truck gets looked at every time I head to Vegas and go past the check point for the Hoover Dam .... I have gotten checked at the Baltimore tunnel, and at the Chesapeak Bay bridge ....

 

[OneBrightGator]

That is funny
Actually steel tanks exploding is not entirely uncommon. I am referring to the old 2250 psi tanks now but there was a picture circulating around of a car that had a tank explode inside while parked in the sun. I remember seeing an exploded steel tank on display at a dive shop. Might have been at Oceanquest in Vancouver. Toodles, you around?

Now, come on, steel tanks from the 50's are a whole 'nother ballgame. You don't need to double disk those because you shouldn't be overfilling those in the first place!

Oh, well if there's a picture of it on the internet then it must be real!

If there has been a steel tank that's exploded I would be interested in the details.

 

[H2Andy]

My truck gets looked at every time I head to Vegas and go past the check point for the Hoover Dam .... I have gotten checked at the Baltimore tunnel, and at the Chesapeak Bay bridge ....

do you have a bumper sticker that says "Jihad Martyr On Board" or something?

:14:

 

[OneBrightGator]

My truck gets looked at every time I head to Vegas and go past the check point for the Hoover Dam .... I have gotten checked at the Baltimore tunnel, and at the Chesapeak Bay bridge ....

I was answering Andy's question in regards to Florida DOT officers.

Was your truck considered a commercial vehicle at the time? What were the circumstances of the inspections (were you pulled over individually or inspected at a roadside station)? Who did the inspections?

 

[in_cavediver]

I've seen this reason given many times for taking the risk of double disking, however, I've never seen any evidence of it actually happening.

It just makes no sense to me and the phsyics don''t support it on properly maintained equipment.

i think the genesis of the double-disk thing was to be able to pump more
air into a tank... not so much a safety thing as a "let's go further" thing

First, I have seen one go underwater, not in person but I surfaced just before the diver who lost one. It was in upstream cow. From what I recall, he said it blew at around 3000 psi in a set of 112's.

Second, Andy you're right. Its not for the safety in the direct sense but for matching the pressures of over filled tanks.

 

[Quarrior]

First, I have seen one go underwater, not in person but I surfaced just before the diver who lost one. It was in upstream cow. From what I recall, he said it blew at around 3000 psi in a set of 112's.

Second, Andy you're right. Its not for the safety in the direct sense but for matching the pressures of over filled tanks.

As I posted in my other thread, was the tank and valve properly maintained? I have the disks on my HP130's changed every year during the vis.

 

[lakewinni]

This is the first case I have heard of a burst disk failing underwater. Can you share more details?

Burst discs that are raised on the back of the manifold can be dislodged and caused to flow if impacted by a force (you swimming or scootering full force into a rock ceiling). Saw it happen once, then did a test with a junk valve I had and a hammer. I've also asked other people and heard of it happening.